Training Manual on Inverter Technology

Renewable Energy Technologies in Asia:
A Regional Research and Dissemination Programme
PHASE II
For Photovoltaic Applications
Training Manual
Prepared by
Solar Laboratory
01 Mac Dinh Chi St., 1 District
Ho Chi Minh City
SR Vietnam
CONTENTS
Page
Lesson 1
Overview of Development of Inverter.
By Phys. Trinh Quang Dung
01
Lesson 2
Renewable Hybrid Power Supply Unit Smart 1000
a combination of Charger - Inverter UPS Unit
By Phys.Trinh Quang Dung
Eng. Nguyen Truong Duc
Eng. Le Sy Thang
09
Lesson 3
Sine-Square and Sine-Modification Inverter
By Eng. Tran Phi Cong
26
Lesson 4
High Frequency Inverter.
By Eng. Nguyen Truong Duc
Eng. Tran Phi Cong
35
Lesson 5
True Sine Inverter.
By Eng. Le Si Thang
42
Lesson 6
Computer Designing of Inverter.
By Eng. Nguyen Truong Duc
50
REGIONAL TRAINING COURSE ON ‘INVERTER TECHNOLOGY” 16 -20 October, 2000 HCM City Vietnam
LESSON 1
OVERVIEW OF DEVELOPMENT OF INVETER
I. BRIEF HISTORY AND TECHNICAL DEVELOPMENT
1.1 Motor Generator Inverter:
Since 1940 inverter has appeared and the first uses were in the Second World War.
This time together with a development of electronic lamps, the need of high DC
voltage had been requested. During the time of world war’s II when Navy Ships ran
on DC power only then DC source was urgently needed.
That time, the Invertor was Rotary Inverter. In fact this was a motor generator,
which could convert 12 VDC, 27 VDC, into
110 VAC, 220 VAC and it was only way to
convert DC voltage into AC voltage.
The most popular brand of that era was
Redi – Line. Over half of century passed but
Redi – Lines still appear in use in the country
- side around us. These rugged units were
quite reliable, strong enough and produced
AC voltage with a low efficiency about 50%.
The Rotary Inverter had many disadvantages
as very high start current of 20A – 30A and no
stable out put voltage. It also could not have
start up surge capacity, which limited applications of inductive loads as fan, pump,
compressor etc… Because of their quite high reliability, Blue Bird Rotary Inverter
still had been produced until the late of 1970’s and early 1980’s.
1.2 Electronic Sine Square Inverter.
Trip-lite company founded in 1992 was the first produced a unique automobile
headlight, which has been Invented by Graham Tripped. Later, the product line
expanded to include Electronic Inverter. In that era, the early units used mechanical
vibrator to oscillate DC power into square waveform AC, the mechanic vibrator
when it oscillates which turning on and off continuously contact-points to make
square wave current. This kind of Inverter could response only one defined load and
short lifetime because of contact points easy damaged.
Solid-state semiconductor devices were born in middle of 20 century, which
supported to new generations of Inverte: Full –
Electronic Inverter in the early 1960’s. The solidstate transistors replaced the mechanical vibrator,
which maintains longer lifetime of the unit. This
1
event declared a termination of Rotary Inverter Technology as well as mechanic
vibration system. Since this point, the motor – generators no longer produced
anywhere. Although that, unregulated square wave design of this kind Inverter could
not go over and many technical problems were still open as unstable output voltage,
no surge power, no frequency control etc…
This time Inverter could response only for resistive loads but they was not possible
to run reactive loads as motor, Ice – creamaker, pump, microware oven etc… These
weak points limited applications of Inverter and they had almost fallen in forgetting
of people.
Later on a design of frequency control was applied to allow a steady draw, which
had improved the time-by-time and formed modified sine wave, which is still very
popular for today.
On basic of this technology, Tripp lite has produced power Inverter, UPS devices
(Uninterruptible Power Supply). The company provides products in worldwide
market.
In 1979 Vanner inc. introduced the first 1000W sine modified wave Inverter
thanks to it’s parented power transistor drive technique. That time it was a big
achievement and subrising, because of an unheard efficiency of 87%. The first
application of this Inverter was used in ambulances. Few years later, the application
was expanded into various types of vehicles including remote television vans. After
that following the market request, product line expanded with 2200W and 3000W
Inverter.
After the world energy crisis in 1973, Renewable Energy Sources have been
mentioned and attracted energy policy markers. One of the urgent request was how
to produce high quality AC electricity from RE and one again the companies,
researchers, engineers have jumped in a competition of Inverter Technology.
During 1980’s there were two companies manufacturing Inverter in USA for the
world market: Heart interface and GTO Electronics. There were some others in
Europe and Asia but they were small. In 1986 Heart split off to form Trace
Engineering, which later became a famous Inverter manufacture in the world. The
Heart Inverter had a battery charger /converter built in and was the pioneer reached
highest efficiency that time over 90%. Another strong point of it’s specification was
the surge power had got three times.
In 1986 one of the Inverter models included a microprocessor control was
mentioned. On the technical point of view, we could classify that the first generation
Inverters used Metered Darlington Technology. This special circuit metered base
current to power a transistor proportional to load. The magnetic design increased
efficiency. Second – generation Inverters used FETs (Field Effect Transistors), since
FETs have almost no switching losses, efficiency was markedly improved.
In the last decade of 20th century, the Inverter Technology has strongly developed
with a big worldwide competition. In 1987 Exeltech was founded and manufactured
High Frequency Sin Ware Inverter. It claims the first redundant Inverter system,
“hot” swappable capability and modular design. This kind of Inverter do not used big
transformator that why they have quite small size, much lighter and convenience for
mobile application.
Stat-power Technologies Corporation head quartered in British, Columbia,
Canada was founded in 1988 also manufactured M.S.W Inverters using High
Frequency design. The company provided portable power for remote regions.
2
In 1990 IC (Integrated circuits) were applied which allowed the creation of
energy management system and microprocessor in Inverter Technology. The first
microprocessor controlled Inverter/Charger was introduced in 1993. The advantages
of M.S.W Technology are efficiency and relatively economical cost although that the
M. S. W Inverter however, still cannot run all kinds of loads because of poor peak
voltage regulation and the fact that the AC output is not a pure sin wave. Beside this,
M. S. wave Inverter also makes interference to loads in some cases.
Trace Engineering developed and patented improvements to the modified sine
wave technology in their sine wave series Inverter. While not a true sine wave, the
output is a multi – step approximation that
results in fewer load incompatibilities. The
charger is more efficient and results lower
AC. This sine wave series Inverter still has
several other features as including an
automatic generator start/stop, a battery
temperature sensor and three independency
set voltage relays. Trace Engineering has
covered big part of the global market that
why in South Africa the name “Trace” it
means “Inverter”
In 1995 Stat-power introduced a pure sine
PV Series Inverter
wave
Inverter/Charger
using
high
Frequency Switching Techniques, they were successful in producing a high output
charger with a power factor approaching “1”. This is almost not distortion at the DC
port in both Inverter and charger mode which could be viewed as a technological
milestone. Pure Sine Wave Inverter opens a new era and any limitation of use is
remained. Although that Pure Sine Wave Technology just in start, we expect a quick
development to sweep out some barriers as high cost, difficult to maintained etc…
and catching a potential world market. The Pure Sine Wave Inverters have given
good chance for grid – connected design as well as synchronous of several Pure Sine
Wave Inverter to increase power. We could say that since 1995 a “boom” of
competition for Inverter manufacturing. Millions solar roofs, thousands of wind
farms, micro-hydro projects which have requested big amount of Inverters. Thanks
to the revolution of Renewable Energy in world wide together with big
manufactures, a lot of new electronic companies as Steca, Leomics, AST, Zenit have
jumped in the exciting market. Nowadays appearing a variable service of Inverters
as Inverter for solar pump, for AC solar module for grid – connected use etc…
The smallest Inverter is one supplying for AC
module which size is only
108 x108 x30mm or 220x70x20mm. Output
power only 80W – 100W and catching an
efficiency of 94%. They are introduced by Trace
Engineering USA and OK service company of
Neither Land.
3
The larger pure sine Inverter has already built up to a of power of 20 KVA and
surge power 200% . It runs big advanced micro processor control with soft start. The
efficiency gets over 90%. Stable output voltage and frequency, full protection for
overload and short circuit, current mode control, automatic low battery shutdown to
protect
battery,
variable speed fan cooling. It’s
weight is 250 kg
and could operates in poor
condition up to 450C and relative
humidity 95%.
AC Module Inverter
II. DEVELOPMENT
INVERTER IN VIETNAM
During 1985 –1990
on network and three
all main cities. An urgent
power from battery or an
electronic company Divu
and introduced Divu
with a max power of
surge power and responded only for resistive loads.
Vietnam had not enough Electricity
nights per week were black out in
of Market request was given: AC
Inverter. During 1987 – 1990 an
HCM City jumped in product – line
Inverter. It was sin square Inverter
300w. The quality was poor, no
SPECIFICATIONS OF LEONICS TRUE SINE INVERTER
The efficiency was low about 60%. Later on in short time the imported Inverters from Taiwan
AND South East Asia and Copy imported – Inverter covered quite small and poor market that
time there for Divu company also stopped their product.
4
A serious research and good design of Inverter has been done
by AST Company during 1986 – 1989. In 1990 AST Company
put it’s products in local market with two ranges: 300W and
600W sin modified wave Inverter with stabilizes output voltage
220V ± 5% and full – protection system.
Since 1995 thanks to open – door policy, the economic of
Vietnam going on fastly and Renewable Energy Sources as solar,
wind, micro hydro have strongly developed. One again Inverter
has become “hot” request for remote, mountainous regions as well as on Island and country side
A lot of electronic companies have put in market their Inverters as RoBo, Solar, Hansin
etc…. The common disadvantages of the Market – Inverter are poor quality, high stand by
current or low efficiency. AST company is still pioneer among them for quality and the
company has continuously done research and improved design and quality. AST is also leading
ahead in manufacturing UPS devices and Auto Stabilizations. The company networks have
distributors and agencies along the country and sell out 5000 products/month approximately.
Solarlab is a National Laboratory belongs to Vietnam National Center for Sciences and
Technologies. It is a pioneer and leader of PV development of Vietnam. To serve own activities,
Solarlab has researched on Inverter – Technology since 1990 and has Introduced the first “
SOLARSTAT” equipment in the Solar Station and Cultural House at Tam Thon Hiep District
HCM City in Vietnam end of 1990.
The SOLARSTAT kept “Industrial Model and Design” issued by Department of Invention and
Properties of Vietnam during 1992 – 1998. The SOLARSTAT is a
heart of Battery Charging Center
and Cultural House, It consists of
four Charging Channels by solar
modules and a built in sin square
Inverter of 300W. Later on,
Solarlab
has
continuously
developed and improved quality of
it’s Inverters with 500W and
1000W. The Inverters of Solar lab
SOLAR START
manufactured specially for PV.
Applications that why the quality
and energy saving are priorities. The stand by current of Solarlab’s
Inverter usually was 2/3 of the market Inverter and high surge
power. During last 10 years. Solar lab put in operation about 60
SOLARSTAT along the country. In 1993 nine SOLARSTATs
Certification of Solar start
were exported to Republic of Mali in Africa according cooperation
with FONDEM France and one SOLARSTAT was exported to Lao P.D.R in order of MOSTE
Vietnam in 1997. The SOLARSTATs provide electrical power for various PV. Applications as
Telecommunication repeaters, Satellite – Para ball Receiver – Transmitter Cultural Houses, Solar
House, and Local Radio Broadcasting Center etc…
In 1996 Solar lab designed a first High Frequency Inverter in Vietnam following a research
program funded by Sida Sweden. The product
was 50W only but it could not become a real
product because of lacking imported FETs
Since 1997, AST Company and Tectrans
Viet Enterprise has joined to design and
manufactured Smart product with the range of
300W, 500W and 1000W. For short time of 2
years, Smart 300, 500 and 1000 were
improved much good design and quality. It is front of Smart
back of Smart
5
a Hybrid Power Supplied unit built in a power - full good sine modified Inverter. Surge power
gets 200% and unheard efficiency of 90% Full protection as well as UPS function guaranteed.
Frequency controlled, stabilized AC output voltage ± 5%, Hybrid Charging Control process and
Battery Metter System are very competitive advantages of the Smart product – line. Smart 1000
run all kinds of load as: water pump, photocopy machine, glass cutter etc… Especially it
response also fun, refregenerator too. 2000’s is a good start of the product -line of smart with 14
units were exported to Thailand, Philippine and Germany.
APPENDIX: SMART SYSTEM
6
7
Grid-connected Inverter
8
REGIONAL TRAINING COURSE ON “INVERTER TECHNOLOGY” 16-20 OCTOBER, 2000 HCMC
LESSON 2
RENEWABLE HYBRID POWER SUPPLY UNIT SMART 1000
I. INTRODUCTION:
Smart 1000 is a Renewable Hybrid Power Supply Unit, which has manufactured by
AST electronic CO. & TECTRANS VIET Enterprise. It is an intelligent equipment, which
has many advantages and conveniences for Use.
The UPS function allows Smart 1000 can operates everywhere catching network.
Especially in the domain of communication and informatics applications the continuous
power all of time is very important fact. Which guarantee dropping out communication
signal and losing database.
On input source, Smart has a wide range of choice whatever: grid reconnected, Solar
module, Wind, micro hydro generator as well as Diesel generator… which makes Smart
becomes a power source everywhere and every time.
You know, solar radiating is everywhere in Vietnam and almost everywhere in the
world. Furthermore, Solar power is a renewable and infinite power. Therefore Producers of
Smart has designed Smart 1000 use solar power is a basic power source. Besides, others
renewable are Wind power, hydroelectric power has been used too.
Smart 1000 can use in mountainous, remote area as well as in island... In mountainous
where has much solar radiating and waterfalls you can use solar power and hydroelectric
power to charge battery and use other applications. In coastal region or island where have
much solar radiating and wind you can use solar power and wind power. With countryside
you can use solar power and diesel generator…
Now, in Vietnam Smart 1000 has used on cultural boats and health service boats.
Smart 1000 has been exported to some countries in ASIA. For example: Thailand,
Philippine … and it’s going to export to Germany on next time. It expect a big market
future thanks its advantage
II. DESIGN AND OPERATION
2.1 Description
Mobile independent hybrid power station for 12V DC and 110/230V AC, 50 Hz,
built-in mains charge (AC 230 V) and solar charger regulator (DC 12V) for solar modules
up to 500Wp (40A) charging capacity, DC/AC inverter (modified sine wave) with rated
9
power capacity: 1000 W (surge power capacity = 2000 W), built-in uninterrupted power
supply (UPS) device for safe supply during power cuts, multiple connections for 12V DC
power charging systems (wind, hydro, generator), main and battery voltage indicator,
charging current indicator, system protection for low and overload, 12V DC mains
adaptor, switch-able 1.5–3–4.5–6 –7.5–9–12V, 1 cigarette lighter socket for 12V DC and 4
AC safety sockets for 110/230V, system mounted in a roller rack in ready-to-use
performance for direct connection of 12V DC battery bank (180Ah – 400Ah); weight
without battery bank ≈ 30 Kg.
Smart 1000 is a mobile intelligent hybrid power supply and control unit for AC and DC
appliances in home, offices and remote dwellings. It’s an AC power source for anytime
and everywhere
Smart 1000 is an ideal and unique equipment for reliable energy supply in isolated area
with selected and approved components, guaranteeing: high power quality, high reliability,
quiet operation, multiple possibilities.
Smart 1000 is a ready-to-connect unit, simple to install, easy to use and requires no
maintenance. Charging power sources for Smart 1000 are besides grid or generator - a set
of two qualities certified solar modules in combination with a sophisticated and highly
efficient wind generator.
Smart 1000 is capable of supplying power for: Lighting, Refrigeration, Air
Conditioning, House hold Appliances, Tools, Communication Equipment, Radio, TV,
Video, Computer, Charging Facility for DC source, etc.
Smart 1000 is used with Power sources Renewable Energies: Solar Module 100Wp300Wp, Wind power Air 403, Micro Hydro Gurgler PT02 (150W-300W), Grid 220V, and
Generator 500W-3000W.
Hybrid Power Station is a hybrid power supply uses different sources of renewable
energies. The equipment consists of three parts as following:
Charger Regulator
* Solar & Grid
* Power
12 VDC
Storage System
For Loading:
- TV
- Lighting
- Computer
- House appliances
U.P.S / Inverter
12V / 220 VAC
220V 50Hz(60Hz)
Fig
ure 1: The Block Scheme of Hybrid Power Station
10
The charging process of Charger Regulator for Solar and Grid is built in. And the
Generator, Micro Hydro, Wind had the control charging regulator themselves.
The full protection system allows the equipment auto-operates to against most of
troubles keeping high reliability of the equipment.
§ Energy charging
The charging of Hybrid Power Station can be applied with many variable kinds up to
local conditions such as Grid, Diesel Engine, Micro Hydro, Wind or Solar Generator. We
can use single or Hybrid Energy Power at the same time for charging. However, the most
important charging principle is a total charging current must not to be over a limit of:
30Amax for H.P.S Smart 1000
The user should read carefully the catalogues when charging with Wind, Micro Hydro
before connecting into H.P.S Smart 1000.
TECTRANS-VIET is willing supply Synchronous Renewable Energy Sources such as
Solar, Wind, Micro Hydro sources that are suitable with the equipment Smart
For charging we must connect in exactly positions. Grid connects to AC-in, Solar into
Solar-in, Wind or Micro Hydro into Wind/ Hydro-in, Generator into Generator in. The
important note is a right connection to ⊕ and of DC sources. For Grid charging, turn on
AC power contact to Charger.
§ Use DC power:
To use DC power, turning on the contact DC power ON, lighting indicator indicates
12V DC is on DC-out. When Battery voltage gets lower than 10.5V, empty indicator
lighting on and DC source auto cutting off to protect Battery Bank. When the Battery Bank
is full charged, DC source will auto Reset (or press Reset button).
DC source can also supply from contact cigarette in the backside, note follow correct
pole ⊕ and printed in equipment.
§ Use AC power:
The UPS/ Inverter provides a continuing power of 500W or 1000W with voltage
220V AC ± 5% 50Hz (or 60Hz) for: TV, Video, Lighting, Computer use. Surge power is
1000Wmax with and 1500Wmax with Smart 1000 SS in 5 seconds. Inverter supplies AC
110V - 220V with Sine modification waveform. So, when use H.P.S for running motors
which have high inductive characteristic, please carefully ask expert about the equipment.
When the Smart connects to a Grid power, AC source connected directly with
network. If the AC source suddenly interrupts the UPS function will be auto-change to
Inverter within 1 second.
When AC source disconnect by overload or short circuit, please check carefully and
repair to be sure troubles overcame, and turn off AC contact then turn on, AC source will
be reset.
When using with invertors, the loading must turning on slowly to avoid suddenly
heavy loading for Smart.
11
§ Indication systems:
AC Power: lighting at ON position and AC voltage.
DC Power: lighting at ON position and DC voltage.
Charger: ° Grid Power Led will be lighting if charges by Grid on AC - in 220V AC.
° Solar Power Led will be lighting if charging by Solar Modules on Solar in
12 V DC.
° Diesel Power Led will be lighting if charging by Generator 12VDC on
Diesel input.
° Wind / M. Hydro Led will be lighting if charging by Wind or Micro Hydro,
Generator ON Wind / M.Hydro in 12VDC
Battery: ° Full Led (100%) will be lighting if the voltage of Battery Bank is 12.5V.
° Normal Led (60%) will be lighting if the voltage of Battery Bank is 12V.
° Low Led (30%) will be lighting if the voltage of Battery Bank is 11V.
° Empty Led (10%) will be lighting if the voltage of Battery Bank under
10.5V and cut off DC-out.
Ammeter: showing charge – current into Battery Bank if equipment is charging by any
energy sources: 50Amax for Smart 1000
VDC meter: show voltage in the two pales of Battery Bank from Storage Systems
capacity 200 AH / 300 AH.
VAC meter: show voltage 220V AC ± 5%, 50 Hz or 60 Hz. This voltage will appear
when inverter is using or the Smart connecting to Grid.
§ Protection systems:
Smart 1000 is high reliability with full protection systems, includes:
> Against overload and short circuit on outside.
> Against inverse charging on Solar in.
> Against overcharge.
> Against exhausted Battery Bank.
Low voltage
disconnection
2.2 Design
2.2.1 Block Scheme
Oscillator
50 Hz
UPS
controller
220V AC
INPUT
12V DC
OUTPUT
Ejection
controller
protection
block
220V AC
OUTPUT
Driver and
Tower
Solar Regular
V DC
INPUT
Diesel source
Wind/M. hydro
Rectifier
DC
Ampere
Meter
Charging indicator
system
Overcharge
Protection
Battery
12state
Indicator system
Store battery
Bank 12V DC
100/200 Ah
Transformer
inverter
DC
Voltage
Meter
AC
Voltage
Meter
AC
AC
Ampere
Amper
Meter
e
110V AC
OUTPUT
2.2.2 Block function
• Solar regular, Diesel source, Wind / M-hydro block: there are energy charging sources,
the charging of Hybrid power station can be applied with many variable kinds up to local
conditions such as Solar, Diesel, win and Micro Hydro.
• Charging indicator system block: include Leds such as Solar Power Led, Generator
power Led… to indicate energy charging and charging state. For example: Solar Power
Led lighting if charging by Solar Modules, Generator power Led lighting if charging by
Diesel generator…
• DC Ampere meter block: show current charge for battery.
• Overcharge Protection block: Overcharge Protection.
• Battery state indicator system: include Leds to indicate Battery state. When battery is
full, the FULL LED will be lighting. When voltage of battery is low the LOW LED will be
lighting…
• DC voltage meter: display battery voltage.
• Store battery bank block: Battery bank from storage systems capacity 100/200Ah
• Low voltage disconnection block: disconnect to load when battery is Low voltage
• Oscillator 50 Hz block: change DC voltage input to 50Hz potential pulse.
• Ejection controller protection block: against overload and short circuit on outside
• Driver and power amplifier block: control power amplifier to amplify 50Hz potential
pulse before it goes into transformer. To intensify output capacity
• Transformer Inverter block: change 50Hz potential pulse to 110/220V AC output
• AC voltage meter: display AC voltage output.
• UPS controller block: control UPS mode. When the Smart connects to a grid power, AC
source connect directly with network. If AC source suddenly interrupts the UPS function
will be auto-change to Inverter within 1 second.
2.3 Principle Circuit
2.3.1 Main circuit
OPTO
220V AC IN
Gate
1k
220/50v
Vcc
RELAY 1
K
A
IN
TRANS
C1815
Vcc
470/0.5w
Gate
5k6
RELAY 2
OUT
1K
1k
15v AC
220V AC IN
TRANS
13
+B
MAIN CIRCUIT
SW
LM317
3.3/1W
10/5W
10/5W
D613
Vin
A1013
2
Vcc
560
1
220/50v
6k8
470k
+Vout
ADJ
100/100v
3
6k8
220/50v
2k2
6k8
9v
6k8
6k8
103
5k
10
103
3v
TS
1MF
15k
18v
1MF
2k2
C1815
15k
Text
4007
Text
103
10MF
15V
2k2
C1815
6v
R6
100MF
100
(60N06 * 6)
1K
A1015
R1
4054
10
2k2
4054
10/5W
C1815
+B
6V
R6
100MF
(60N06 *6)
100
1K
A1015
4054
10
4054
4M/250v
R1
Main circuit contains Power supply circuit and associate circuits to apply power and
associate other circuit together.
Power supply circuit: In Principle of Inverter changes DC to AC voltage. To do that,
it needs a stable oscillator 50 Hz. So that, request for power supply is voltage and current
supply must is very stable. Therefore in Power supply circuit must have Voltage stabilizer
and current stabilizer.
In circuit, power supply on B+ through A1013, C1815 and D613 transistor to pin 1 of
LM317 will create a voltage and current stable on output pin 3
2.3.2 Oscillatory circuit
14
An oscillation at 12800 Hz was created IC 555 on pin 3 and conducted to pin 1 of IC
4520. After that, it will be divided to have a signal with 800 Hz frequency. This signal was
send pin 9 and on output at pin 14 we have a signal with 50 Hz frequency.
Then it will be modulate to have DR1, DR2 signals. They are conducted to two
amplifier-powers. Each one contains six mosfet-transistors (60N06). They were in parallel
together. DR1, DR2 signals drive two amplifier-powers to have a sine signal with 50 Hz
frequency. Amplifier-powers’ outputs were conducted to primary coil of transformer and on
secondary coil we have a 220/110V AC.
15
50HZ800HZ
DAT CS
IN/LINE
DONG BO
4
2
R
CVolt
TRIG
5
10K
68K
1
Q
DIS
GND
8
VCC
THR
GND
GND
3
6
VCC
104
10
3K9
9
DIODE
RES1
POT1
U?C
LM324
10K
10K
10MF
470K
12
8
CAP
13
RES1
R
DIODE
10K
U?A
4520
Q3
Q2
Q1
Q0
14
5K6
220K
GND
6
5
4
3
GND
10K
2
1
7
DIODE
U?D
LM324
EN
CLK
GND
7
555
CAP
POT1
U?
ZENER3
GND
VCC
R
U?B
4520
14
13
12
11
7
Q3
Q2
Q1
Q0
10K
U?
DIODE
100K
33K
GND 51K
DIODE
5
6
CAP
U?B
MC4558
6V
47K
6V
3K3
470K
DIODE
103
3K3
470K
3
1
2
7
6V
A
ELECTRO1
DIODE
LM393
1
U?B
LM393
2
3
LM324
5
11
6
4
U?A
8
4
47K
104
GND
6V
103
220K
68K
7
10K
103
U?
12
13
1
2
10K
6V
22K
U?D
4011
10K
8
GNDCAP
9
104
VCC
11
3
U?
5
GND
U?B
4011
RES1
222
DIEU CHE
DR2
16
U?C
4011
10
POT1
RES1
6
47K
U?A
4011
4
GND
5K6
222
DR1
RES1
PLUG
VCC
OSC CIRCUIT
U?B 220K
LM324
EN
CLK
5
DIODE 4.7MF
6
LED
15
U?
SCR
VCC
10
9
U?
2.3.3 Transfer circuit
Function of this circuit is to transfer between inverter and UPS mode. In circuit we
used OP-AMP LM339 makes comparing circuit to detect signal from grid electricity. Duty
of this circuit control relay 1 and relay 2 to decide automatically supply energy to load from
grid electricity or Inverter. Transistor A1013 will control charging battery from grid
electricity.
TRANSFER CIRCUIT
820K
14
8
6
VR02
33K
VCC
NPN
10K
5K6
LM339
12
10K
GND
104
4
4
4K7
U?A 220K
104
15
22MF
LM324
14
GND
Z
Z1
Z0
Y
Y1
Y0
3
5
330K
LM339
DIODE
VCC
GND
10K
NPN
GND
DIODE
1
2
U?B
13
12
X1
X0
X
DIODE
13
10
0.47MF
11
6K8
3
D
11
CAP
9
10
11
6
C
B
A
INH
2
1
104
7
VEE
VCB
DIODE
560K
10K
GND
6V
51K
U?
10K
DIODE
VCC
U?
GND
5
7
6
4053
LM324
DIODE
6V
D
2K2/1.2W
14
VCC
LM324
100K
100K
104
C
10
100K
8
9
GND
10K
51K
DIODE
47K
13
51K
BD2
12
104
1K
TRANS1
223
10K
BD1
LM324
2.3.4 Display circuit
Showing operation state of system by leds. In this circuit, we used OP-AMP LM339
compare input signals with correlative reference signals. They will control leds when input
signals change.
DISPLAY CIRCUIT
4007
+B
1.5K
10MF
TS
Charging
GRID
3V
10K
1MF
1.5k
10K
3
17
TS
Full
5
10K
2
4
1.5k
12
6V
LM339
Normal
TS
1.5K
Normal
.5k
TS
800HZ
C1815
5K6
102
51K
10K
10K
A
5
2
SYN
NPN
GND
VCC
3
2K7
220K
4
50hz
U?
A1015
5K6
LM339
LM339
PLUG
DIODE
680K
10MF
22K
2K2
39K
22K
10MF
33K
TS
CHARGE
9
7
1
2K2
1K
C
1K5
B
2K2
DIODE
104
COMPARE
103
5K6
5K6
120K
VR01
1M
0.47MF
IN/LINE
VCC
B> C
2.3.5 DC and charging control circuit.
Function of this circuit is to control charge for battery. It can cut off overload and
overcharge state.
When voltage of battery is low, A1015 transistor will active to control charging for
battery.
When battery is full on LM393’s output has a signal to control C1815 transistor on
pin B and this transistor active to supply 12V DC to load. At the time, it cut off charging for
battery.
CHARGE CONTROL CIRCUIT
DIODE
SCR
PLUG
B1K5
47MF
PLUG
A1013
U?
TRANS3
SCR
9V
RES1
GND
4K7
GND
33K
GND
DIODE
GND
DIODE
1K/1W
U?B
U?D
TRANS3
PLUG
5
12
7
14
13
6
5K6
224
47K
LM324
RES1
LM324
330K
6V
PLUG
2K2
220MF
3K3
PLUG
U?
DIODE
1K5
DIODE
C1815
U?
18
1
2
DIODE
GND
47K
GND
33K
330R
22K
RES1RES1
15K
LED
50K
39K
11
PLUG
10K
8K2
3
LM324
12V
2K2
U?A
47MF
PLUGDIODE
VCC
33K
100K
4
ZENER2
GND
DIODE
1
33MF
GND
2
GND
VCC
3K9 3K3
GND
U?
2.4 Circuit board.
All circuits of Smart were divided into several small circuit boards. It is easy to fit
and repair. Include:
- Main board.
- Osc board.
- Transfer board.
- Charge board.
- DC out board.
- Display board.
- AC charge board.
2.4.1 Main board.
It’s the motherboard to combine several small circuit boards together. For example:
OSC board, transfer board and charge board.
19
2.4.2 OSC board.
It contain oscillator and divide circuit to create a signal at 50 Hz frequency.
20
2.4.3 Transfer board.
It contains transfer circuit.
21
2.4.4 Besides, we have some circuit boards. For example: charge board, DC out board,
Display board and charge board.
22
23
24
2.5 Technical specification.
Equipment
Smart
1000 SS
AC Voltage
DC Voltage Wave form
Power Continue
Surge
Sine
230V/110V ±
Modificatio
1000 W
5%
10,5 V ÷14V
n
50 Hz or 60 Hz
Battery
Bank I Charge
300 Ah
1500W/5sec 400 Ah
35A max
Integrated control-battery system in “plug and play” performance installed a mobile
roller rack, optional 12 or 24 DC.
• Powerful battery bank: 12 – 180 to 400Ah.
• High cycle charge battery bank in low maintenance or maintenance-free performance.
• Built-in DC/AC inverter 230/ 110V, optional in 50 or 60 Hz performance, 1000W
continuous power, 2000W peak surge power.
• 12V system with step wave inverter
• Built-in main charge (230V) and solar charge regulator optional 12V DC for solar
module up to 5000W charging capacity
• Built-in uninterrupted power supply (UPS) device activated when connected with public
grid.
• Multiple connections for 12V DC power charging system (Wind, Hydro, Generator)
• Mains and battery voltage indicators. Protection against
• Current indicator for AC grid charging and DC charging source.
• Battery protection against over and low load.
• Multiple outlets for 230/110V AC and 12V.
• Prepared for direct connection with selected solar, Wind, and Hydro generators.
25
REGIONAL TRAINING COURSE ON ‘INVERTER TECHNOLOGY” 16 -20 October, 2000 HCM City Vietnam
LESSON 3
SINE SQUARE AND SINE MODIFICATION INVERTER
More and more technologies, or circuit designs have involved in the quest for creating
higher power AC from low voltage DC sources. This lesson will examine some design
techniques in which we already done.
I. LOW FREQUENCY TRANSFORMER BASED INVERTER.
The following technologies are based on low frequency switching of the low DC
voltage, applying the DC pulses to a step- up transformer. Two common technologies are
the PUSH_PULL technology is suitable for production of Square and Modified Square
ware and sine-ware outputs.
The block diagram of a low frequency transformer based inverter is shown below.
12VDC
BATTEY
12VAC
Low frequency
Transistor
Switches
120VAC
Low frequency
Transformer
AC Loads
(Push-pull or Bridge)
SQUARE WARE AND MODIFIED SQUAREWAVE INVERTER.
It is called SQUAREWAVE INVERTER because of its shape of the
output waveform.
(See figure 1)
120 VAC RMS
Figure 1,Square Wave output Wave
Square wave inverter were the “ Original Electronic “ inverter .The first versions such
as Tripplits used a mechanical vibrator type switch to break –up the low DC voltage into
pulses are then applied to a step-up transformer. With the advent of semiconductor
switch, the mechanical vibrator was completely replaced by “ Solid-state “ transistor
switches.
Figure 2 is a common circuit referred to as “ PUSH_PULL “ technology to produce a
square wave output.
26
Transformer
Trasistor Switch
Battery
Negative
AC Output
Square Wave
Battery
Poaitive
Battery
Negative
Trasistor Switch
Figure 2.
The basic theory of a Push-Pull design is as follow: the top Switching transistor
closed and causes current to flow from the battery negative through the up-half primary
transformer to the battery positive. This action indices a step-up voltage on the secondary
side of the transformer. (See figure 4A). After a period of time, the switch Flip-Flop.
The top switch opens and then the bottom switch closes allowing current to flow in the
appositive direction. (See figure 4B) This cycle continues and higher AC voltage is
obtained from secondary port of the transformer.
The Turn radio of transformer decides the output voltage, the more turns on
secondary side, the higher voltage is obtained.
(Figure 4A + 4B).
Transistor Switch Closet
Battery negative
Battery negative
induced curent
CurentFlow
Battery positive
AC output
Square wave
AC output
Square wave
Battery positive
CurentFlow
induced curent
Battery negative
Battery negative
Figure 4A
Figure 4 b
Transistor Switch Closet
The major problem with the Push-Pull approach is that the current in the transformer
has to susdely reverse directions. This cause a large reduction in efficiency as well as
potential for large transients, thus degrading the waveform, Another drawback is the
transformer that require for the Push-Pull design must have two-primaries,
The output pulse is directly related to battery voltage Since the radio of transformer is
fixed, any charge in battery voltage would effect the peak output voltage .for square
wave, RMS voltage is equal to peak voltage and as a result power output is depended on
battery voltage.
Finally, most square wave inverters have mediocre efficiency (typical about 80 %)
and the idle draw is relatively high.
II. MODIFIED SQUARE WAVE INVERTERS.
The addition of an extra winding in the transformer along with few other parts allows
output of a MODIFIED SQUAREWAVE (often referred to as a modified SINE-WAVE
by marketing types) while still utilizing a push-pull technology)
27
170Vol Peak
120VAC RMS
Pulse height equal to battery
voltage times the turn radio of
the output transformer and
dependent on battery voltage
Figure 5 Modified Square Wave and Off-Time.
The switching cycle is identical to that described in the section on square wave
inverters, except for one additional step .In the switching cycle, another step is added
which clear out the transformer reducing the problems associated with the suddeed
change in current direction. This is accomplished by the off time shorting winding shown
in figure 6 .As one switch opens and before the second switch closes, the switch across
the shorting winding closes, effectively removing the current from the transformer. This
would be like slowing a car to stop and then shifting to reverse, much better than the
situation mentioned previously. Off-time shorting provides a better zero crossing of the
waveform, which equates to better zero crossing of the waveform, which equates to better
ability to operate electronic devices. Improved efficiency and lower total harmonic
distortion of the waveform are other benefits.
Several manufactures accomplish off –teme shorting by placing a solid –siste switch
directly across the AC output lines. This approach works, however the switch is not
isolated from the AC output line, and as a result it is subject to abuse from transients,
which can be caused by reactive loads (I.e. electric motor) Utilizing a shorting winding in
the transformer is preferable due to the isolation provided from the AC output
Transistor Switch
Battery negative
Battery positive
AC output
Square wave
Transistor Switch
Battery negative
Transistor Switch
Figure 6 Push-Pull
The major advantage to a modified square wave is the ability to regulate RMS
voltage by means of varying the pulse width, and off-time period. The pulse width
variation method of regulation is referred to as pulse width modulation or PWM
The idea behind RMS regulation is to keep the area inside the wave from equal at all
times (figure 7A). Since the peak voltage, or pulse height is a product of battery voltage
and the transformer ratio, when the prak* voltage increases the area inside the pulse will
increase if the pulse width remains the same. With a square wave inverter, nothing can be
28
affected about this increasing RMS voltage. But PWM control allows the width of the
pulse to be narrowed, thus maintaining a constant area in sine the waveform (Figure 7 B)
Peak voltage
Peak voltage
Peak voltage
120VAC RMS
C
On the other hand, ifA the battery voltage decrease,
the RMS voltage would also
B
Nominal Battery Voltage
High Battery Voltage
Low Battery Voltage
decrease if the pulse width remains the same .In this case .RMS voltage regulation may
be achieved by the pulse width (Figure 7C).
Changing of pulse –width accomplished by controlling the on and off time of the
transistor switch. Realistically, there is a point where the zero time is no longer presented
as the pulse –width is increase and essentially a square wave is present. Beyond this, the
RMS voltage becomes unregulated.
Modified square wave inverters are great improvement over square wave types they
offer good voltage regulation, lower total harmonic distortion and better overall
efficiency. Electric motors operate much better from a modified square wave and most
electronic equipment will operate with less problems
III. DESIGN AND OPERATION
3.1 General Specification of an Inverter
The most important specifications are following:
1. Input voltage
2. Output voltage
3. Output power
4. Stability of the output frequency under loading condition
5. Stability of the output voltage under loading condition.
6. Wave form on output gate and deformation.
7. Efficiency
8. Protection scheme (overload, low input voltage etc…)
Nowadays on the market there are several types of Inverter using SCR or transistor.
Some type are using transformation, some not using transformation.
Example: The type using SCR gives high efficiency, impulse – resistance capacity
is higher but the exciting cut – off under heavy power is more complicate and it
involves an over current during the starting that make SCR unable to cut – off. The
output impulse is not sinusoidal; getting a sinusoidal impulse will make high loss in
the filter. The type-using transistor is limited by output power but the circuit is more
simple and is easy to operate. It unable to give a good impulse, bad efficiency at the
line polarity, good impulse at the on – off polarity. The types not using transformation
29
have disadvantage in low output power and high cost, due to not using transformation
the current loss is low under the not – loading condition.
3.2 Classification & block scheme
There are some Inverter-types as following:
a. Using SCR series inversion
b. Using SCR parallel inversion
c. Using impulse inversion
d. Using current feed – back transistor
e. Using voltage feed – back transistor
f. Using both current and voltage feed – back transistor
g. Using feed – back transistor with separate exciter or using amplifier –
exciter IC for transistor.
h. Using high frequency DC Inverter with an exciter to Control Mospet
Generally, in three types using SCR the output impulse is rectangular. To have a
sinusoidal impulse it needs a filter.
Types 4, 5, and 6, using transistor give output impulse almost sinusoidal, it’s
frequency and form tightly depends on the load.
Type 7 gives rectangular output impulse almost sinusoidal, it’s frequency is
relatively stable under the various loading condition but the form is strongly depends
on the load.
Analyzed the advantages and disadvantages of above presented types. The step
– method may use. Transistor has following advantages:
- More economical, low cost
- Good output impulse form: The filter is simple, low harmony distortion.
- High frequency stability
- High efficiency due to the transistor operates at D condition.
- Possible of stabilization of the output voltage by means of limiting the exciting
impulse amplitude for transistor.
General block – scheme:
This scheme is now using in SOLAR LAB
30
Fig. 1 Block scheme of an Inverter
- Block 1: Multi – Harmony oscillator or oscillator outputting a rectangular
50Hz impulse.
- Block 2: Single circuit stabilizer, used to create impulse amplitude for each
half – period of excitation. It is possible to control amplitude by means of feed –
back from block 3, 4.
- Block 5a, 5b: Excitation cascade for the power output transistor.
- Block 6a, 6b: Power transistors, connected depending on the output power
- Bock 7: consists of under – voltage and over current protections and an
accumulator charger.
- LC: Output filter (AC)
3.3 Electrical Circuit Scheme
The actual Inverter scheme is showed below: Oscillator creating Q1, Q2. IC 4047
with capacitor C1 and adjustable resistor VR1 creates an impulse with frequency of
100 Hz at position 13 and then this frequency will be divided into 50Hz at position
10, 11.
Single circuit stabilizer consists of: Amplifier IC 4081 and transistors Q7, Q8,
Q9, Q10.
To create an impulse with amplitude is that enough for the excitation cascade.
To control the impulse amplitude of the single stabilizer, a voltage of 10V is
taken from transformation, and then via a rectifier is passed to the position 9 and 10
(U 2). The amplifier takes signal from 7 gives to 2, 6 (U 3). By this way the impulse
amplitude giving to the stabilizer is stable. Excitation cascade of power transistor is a
31
transistor H 1061. Power transistors are connected by Darlington type, each side
consist of three transistor s 3055 with a disturbance protection
Output transformation is winded such as suitable for the voltage of 12V or 24V.
Voltage at the outlet is 110V and 220V; the power must reach the range of 300W ÷
500W
A regulator for adjusting the output voltage is available here. There is also a
batteries protection circuit for the case of overload and voltage drop lower then 11V.
Voltage for the power cascade (6) is feeded directly because of heavy current.
Voltage for the oscillator and blocks 1,2,3,4,5 is given from the relay.
The protection circuit controls relay winding. As the voltage becomes lower
than 11V. The control transistor will cut – off the voltage to the relay, so the blocks
1,2,3,4,5 will not operate, in consequence the Inverter will stop working.
To make the Inverter work again, it needs to charge the battery and push the
SET button for feeding the relay. When the relay is energized, it’[s contacts will be
closed, so block 1,2,3,4,5 will be energized and it make the Inverter work again.
32
33
REGIONAL TRAINING COURSE ON ‘INVERTER TECHNOLOGY” 16 -20 October, 2000 HCM City Vietnam
LESSON 4
HIGH FREQUENCY INVERTERS
I. INTRODUCTION:
High frequency inverter is another approach to creating higher power AC from low
DC voltage. The name HIGH FREQUENCY refers to the speed at which the transistors
switch on and off.
II. OPERATION:
This type of inverter creates low DC voltage from battery power through a transistor
switching stage to change it to AC square wave and then apply it to a high frequency
step-up transformer (which made-up of by Ferrite core) to creates high AC voltage. Now,
this high AC voltage is then be rectified (change back to DC), apply to a low frequency
switcher (H-BRIDGE) creates Utility power AC.
II.1 Block diagram: (Figure 1)
Battery
12VDC
High
Frequency
Transistor
Switches
High
Frequency
Transforme
r
High
Frequency
Rectifier
High Frequency Switcher
170VDC
Low
Frequency
Transistor
Switches
120VAC
AC
Load
(Bridge)
High frequency inverters may be either modified square or sine wave output.
Drawbacks to the high frequency approach are poor source ability for starting motors
and other reactive loads, and the fact that there is transistor switches on the AC output
which are not isolated from the AC load. Transients, which may be created by reactive
loads, can cause failure in the output transistors. Additionally in general the battery
negative is not isolated from the AC outlet neutral in a High Frequency inverter.
The transistor-switching configuration is a H-BRIDGE switch layout with the
transformer replaced the high voltage power supply, often utilizing a fly back
configuration (Figure 12). The high voltage switcher takes a low voltage DC input and
produces a higher voltage DC output. The positive and negative ends of the high voltage
supply are then alternately connected to the AC output lines by the bridge and output is
pulse width modulated. This provides excellent voltage regulation.
.
Transistor Switch
170Volts
Transistor Switch
HighVoltage
Switcher
+
-
35
0 Volts
AC Output
Modified Square Wave
Figure 2: HF Inverter with H-BRIDGE Technology
The voltage being switched in a HF inverter is the high voltage DC .In a low
frequency transformer based H-BRIDGE; the low voltage from the battery was switched
through a transformer. Off time shorting is provided in the high frequency approach by
closing the two transistors across the AC output on the Zero volt side of the high voltage
switcher. Remember, the switcher must off-time short between switch changes.
The three figures below show the states of the switches in one cycle of the high
frequency inverter. Since the H-BRIDGE switcher has already been discussed only a
graphic depiction of the output switch states and current flow is shown.
Figure 3, 4,5
Transistor Switch
Curent flow
170Volts
0 Volts
HighVoltage
Switcher
+
AC Output
Modified Square Wave
-
Transistor Switch
Battery Positive
Battery Negative
Figure 3
AC
Output
Transistor Switch
170Volts
HighVoltage
Switcher
+
0 Volts
-
Transistor Switch
AC
Output
Battery
Positive
Transistor
Switch
Battery Negative
Curent flow
Figure 4
36
170Volts
HighVoltage
Switcher
0 Volts
The main advantage behind frequency switchchers is the very light in weight and
physical size is small.
Disadvantages of HF inverters are poor surge ability due to the characteristics of the
switching power section supplying the bridge (limits their usage to motor load) Lack of
isolation between the transistor and AC loads makes them very vulnerable to transients
caused by reactive loads since there is no transformer to isolate and act as a “ flywheel “
to oppose fast changes in output current. HF inverter exhibits high idle current because
the high voltage switcher runs constantly and this also often causes interference with
TV’s radios. etc.
II. 2 Sine wave output inverters
Just as with modified square wave and square wave output inverters, multiple
approaches and topologies have deloped to produce sine wave output inverters. These
inverters are desirable in that they will run loads more like the utility grid. The downfall
is complexity and expense in building some types of this inverter. A Sine wave is shown
in figure 14 along with several key points of the waveform.
II. 3 Rotary inverters
The earliest type of DC to AC inverters was the ROTARY INVERTER. Essentially
this piece of equipment was a DC motor that turned an AC generator. The rotary inverter
has the advantage of producing a very nice sine wave output at the expense of low
efficiency (typical 60 %) and very kigh idle power consumption.
II. 4 Ferro-resonant transformer inverters
The Ferro-resonant sine wave output inverter takes advantage of the inductive
characteristics of certain transformers. An inductor is a coil of wire that has the ability to
store energy and to oppose changes in current within a circuit. An inductor acts like a
magnetic “ Flywheel “. In other words if voltage is suddenly applied to inductor, the
inductor will react by attemping to slowdown the resulting current rise. Conversely, if the
current is already flowing through the inductor and is suddenly removed, the inductor
will reacts by releasing it stored current and attempt to stop the current from going to
zero. (The electromotive field force of inductor expands and collapses) As the result the
fall time of the current is prolonged. This reaction acts to impede the changes in current.
Unfortunately, inductance causes the transformer to have a relatively low efficiency
(Typically about 50%) and the waveform is very sensitivity to loads
37
II. 4. 1 Circuit description:
Right in center of circuit is IC 1, controlling the “PWM” Pulse width
modulation) .It contains a saw tooth generator, 2 differential amplifiers and a
comparator to modulate the PWM. It also has a comparator to control the cut-off
timing, a 5 v reference and 2 output control: push-pull or 1 of 2. The components at
pin 5 and 6 are to put the operation frequency of converter on 25 KHz. This
frequency is selected to get the Max output from transformer. . The PWM puts the
pulse which has the width change from pin 9 and 10, these pins are damped by 3
parallel of IC 2 to trigger the gate of Mosfet Q1 + Q2 through 10 Ohm resistor
Mostfet Q1 + Q2 energizers the primary of transformer T1. Which is connected
to +12V, each mosfet is energized by a square wave so that when Q1 is conducted,
Q2 is opened and when Q1 Is opened, Q2 is conducted. The ratio of transformer
increases the output voltage from the secondary coil of Transformer.
2 zener diodes ZD1 + ZD2 keep Q1 + Q2 from over-voltage. This zener diode
operates as follow: When mosfet opened, transformer will have a transient voltage
on the drain of mosfet. When this voltage is over the breakdown voltage of Zener
(75v) is reacts by turn on the mosfet to keep the transient voltage… The silicon
diode that is in series with zener diode are to control the negative voltage.
BOÄÑAÛ
O DC-DC
GOÙ
I ' H ' SOÙ
NG VUOÂ
NG
B3
340v
Q5
Q3
B5
R1
B4
+12V
+12V
T1
Q1
~
-
B1
Q4
+
B6
+
~
Q2
Q6
R2
B7
100
385vw
B2
0v
R
B8
B1-Boäkích ñoâ
i
B4,B5,B6,B7,Boäkích coå
ng caù
ch l i
II. 4. 2 Feedback
voltage;
B8-Boäsinh soù
ng xung vuoâ
ng ñi eà
u chæ
nh
B2-Boäkhuyeá
ch ñaïi quaùdoø
ng
B3-Hoà
i tieá
p caù
h li
The voltage divider which is consists of R1 = 1.2 M ohm and R2 = 3.3 K ohm
are used to control the current of high voltage DC from the converter and to
energized the operation amplifier IC5a. This OP-AMP energizes IC 4 (optocoupler). This IC4 isolates the output voltage from input and energizes IC3b another OP-AMP IC5b (inside LM358) s not used.
- Trim pot VR1is used to adjust DC from IC4 in order to have high voltage out.
- Voltage DC from VR1 is amplified by IC 36 and feed through differential
amplifier IC! Across Diode D8 to control the trigger PWM of mosfets when
DC voltage is over +340v, energized voltage decrease, pulse-width increases
until output voltage is corrected.
38
- Notice that 12V is not feed to IC5 and HV of IC4 because HV of IC4 is
needed to be free. There fore these pins are supplied an isolated DC voltage by
Transformer T2. This transformer is energized at frequency of 1 MHz through
C=. 0047 Mf by Q 15 + Q 16 .The secondary of TX T2 is rectifier by bridge
D20 –D23 (1n4148) and filtered by 0,1 Mf. Output voltage is regulated by
zener diode ZD7 = 12V before supply to IC4 and IC5.
II. 4. 3 Current limited
The drain pins of inverter DC – IC3a controls DC. It controls the dropping
voltage across R=430 M ohm that is connected between Q1 + Q2 and negative port
(0V). IC3a amplifier this dropping voltage by 391 and only small amount voltage
drops across resistor just before over current happen. The output of IC 3 is feed Ed
back to pin 16 of IC 1 through diode D7. This would stop the comparator voltage of
IC3 when the current over 30A.
II. 4. 4 Stand-off time
In the push-pull class of inverter, there would be stand off time, if not the mostfet
or power transistor would short. This action can easily happen because 2 mosfet can
open at same moment. The comparator of stand off time at pin 4 controls the output
of the push-pull at pin 9 & 10 occur at the same time by delaying the output when
one pin are low from the other.
The standoff time increases when the first charge to start first C =10 Mf
between 13, 14 and 4 discharge. This action causes the stand off time 100 % at pin 9
and 10.When capacitor charges through R=47k to ground, standoff time discharge
to ground level. To prevent the over-voltage of the battery, it is necessary to keep
the level of pin 2 of IC1 at low. Check the voltage of battery by a voltage divider
10K –12K when the voltage of battery below 10V, the output port of 9 + 10 is close
to turn off the circuit.
II. 4. 5 The h output
Q3
BUK655
Q5
BUK655
340V
1N4148
1N4148
1N4148
1N4148
T3
T5
1.2M
Y
100
pf
240VAC
output
220k
220k
100
pf
100mf
Q4
1N4148
BUK655
Q6
1N4148
BUK655
1N4148
1N4148
T4
T6
3.3k
100
pf
X
220k
220k
560
pf
39
560
pf
100
pf
560
pf
560
pf
As mentioned above 4 mosfet are connected in “ H “ figure through HV. Mosfet
Q Q3 - Q4 - Q5 - Q6 are trigged by the trigger of analog transformer to isolate
from low voltage, the gate trigger of Q3 is include transformer T3, Diode Ñ + D10,
Transistor Q7, Zener diode ZD3, R = 220 Ohm and capacitor C = 100 mf.
To energize Q3, the frequency of 1 Mhz is apply to primary of T3, The output
voltage from secondary ports are rectified by Diode D and filtered by C = 100 mf.
The DC output is fed back through D1o to gate of Q3. When Zener diode ZD8
zener at 15V of gate Q3 -- then T3 open. .
To de-energize Q3, 1Mhz signal is turn off, but this action is not fast enough.
Q7 operates - Capacitor 100 Mfd charges through 220 K – until base of Q7 turn
below 0.7 v to the Emitter -- Q7 rapidly opened to ground the capacitor voltage of
gate Q3 to turn it off immediately.
As previous described Q3 + Q6 are push – pull and Q4 + Q5 are push-pull. The
series transformer T3 + T6 --- T4 + T5 are energized sequently.
To energize transformer T3 + T6, it is necessary to have the series of 1 MHz
signal every 10 us in only 70% time (T1 = 70%) = 7 us .IC5 oscillated series 50 Hz
that is needed for 1 Mhz. IC6 is a timer circuit 7555 that vibrates at 1 KHz and
trigged IC 6. A decade counter CD 4017 with 10 output that decode 5 –6 – 7 0f IC 8
were connected to OR circuit by diodes D17, D18, D19, to control the high output
of NAND (IC10a) Three high output in only 10% or 30% of time. After reversed
by IC 10a, the output is high in 0% of time as already dad IC 10a triggers pin 8 + 11
of IC 10 b + IC 10c, pins 1 + 13 of IC 10b + IC 10c are connected to complement
output Q + Q every time it get clock-pulse from 5 of IC 8 every 10 us the reset
input of IC 10b + IC 10c are connected to 1MHz oscillator IC 7 incorporated with
another timer LM 7555. IC10b and IC10c can only send signals 1MHz when other 2
inputs are high. This occurs in 70% of time in each 10us sequently.
The supply voltage is 12 VDC from the battery through Fuse 30A is connected
directly to transformer T1. The low path is connected to switch S1 and resistor 10
Ohm; Capacitor 2200 mf in parallel with supply path is used to regulate the current
to inverter. One LED in parallel with supply is to inform the power supply is on and
remember LED must be in series with resistor 2.2K Ohm.
This document s include:
- Schematic diagram of Inverter
- PC board for assembling.
40
REGIONAL TRAINING COURSE ON ‘INVERTER TECHNOLOGY” 16 -20 October, 2000 HCM City Vietnam
LESSON 5
TRUE SINE INVERTER
I. INTRODUCTION.
After almost 50 years of development, nowadays sine modified Inverters technology
is still popular and covered the global market. These Inverters are quite simple, easy for
manufacturing, maintenance and an economic price, although that, disadvantages of
this kind of inverter are many. First of all they response only for resistive loads. The
inductive and relative loads could not run on them as fan, motor, pump, compressor act
… One being technical baries is unregulated sine square wave and uncontrolled
frequency which not allow to make sixnonization among them to increase power from
several Inverter as well as grid connected.
Today, a lot application need high confident frequency – band and accurate
synchronization and big power act... The sine-modified wave could not response well.
True sine wave has been born in this situation to put away all limitations of S.MW
Inverter. True sine wave technology is a mille – store of development, which satisfies
all requirement of development global market. Every kinds of loads, no limited power
range, high confident frequency –band and high efficiency of over 90% are basic
advantages of true sine wave inverter. It also response well for high technology
equipments in field of telecommunication, informatics without any interference. T.S.W
Inverter is ideal product for renewable energy development with grid-on /off
technology.
II. DESIGN AND OPERATION
Design idea: For creating a standard AC source from 12VDC is quite complicated
with several requirements such as: Stable voltage, low coefficient of distortion, and no
drop – power and high conversion efficiency. Transmitting energy from DC source
with frequency 0Hz into AC 50Hz. It could not use line near method but it must carry
by high frequency more than 20kHz then on output it is filtered to get energy 50Hz.
42
1. Block of scheme:
Feedback
Modulator
2
Oscillator creating
standard sine
signal 50Hz
3
Waveform
correction
5
4
Oscillator creating
trigger pulse 20Khz
Low voltage
9
Protector
Overload
10
Indicator
Driver
6
Feedback
Output
220V/50Hz
8
Filter
7
Amp -power
1
Battery 12V
Operation of working blocks:
- Block 1: Battery 12 VDC is a DC power source for changing and supplying
energy to other working blocks.
- Block 2: Creating standard sine signal 50Hz it is most important block using as a
basic signal.
- Block 3: This is the most important to have true sine form reference and
compensation feedback signal from load with standard sine signal to
create appropriate wave 50Hz to distribute to splitting two channel.
- Block 4: Oscillate for creating triangle puls with high frequency 20kHz, carrying
sine wave 50Hz to output terminals of the regulation blocks.
- Block 5: Modulation of appropriate wave and triangle pulse 20kHz to get square
pulse 20kHz with different width.
- Block 6: Driving square pulse 20kHz to fit input pulse of power amplifier.
- Block 7: Power – amplifier consists of two branches operates by driving pulses
to create output power. This block decides working power of inverter.
43
- Block 8: 50Hz filters, filtering high frequency signal into frequency signal
50Hz which be feedback to block 3 for recorrection of waveform.
- Block 9: Disconnecting power when getting any trouble as overload, low
voltage, short circuit to protect inverter.
- Block 10: Indicator indicating all working states of inverter.
Operation of the blocks are controlled by waveform on output of each.
2. Design:
2.1. Design principle:
Block scheme consists of two parts:
- Regulation / controlling block
- Power amplifier block
2.1.1 Usually the regulation-controlled block is designed in following scheme
which is easy finding out devices on market. There are many ways of design
to get standard sine signal some design methods are introduced hereby.
a. Analog method:
The circuit use two IC 1458 to create sine function the first gate create
square wave 50Hz, two following gates create triangle wave from square wave
and calibrate incorrect wave form. The fourth gate amplifier signal to combine
isolated resistance output.
The circuit design is simple, devices are easy to find out competitive price.
Although that, accurate of circuit is not high and it needs to use Bi – power
source crested standard sine. The balance of passive elements is very difficult.
b. Digital method:
44
BoÄPHAÙ
T SOÙ
NG KIEÅ
U BÖÔÙ
C
Vcc
8
4
3
7
6
5
Q 2
¼
4042
D
7555
2
8
7
D
Q
10
13
¼
4042
D
Q
¼
4042
14
11
D
¼
4042
Q
4
1
IC 555 oscillates to create startup pulse (ck). Out put gate F.F using
responding resistance to pull up getting step wave. It is called step wave
creative circuit. After that, they are carried out to calibrated circuit them we
have standard sine
U
U
t
t
R1
Vi
op-am
R2
V out
Following advanced technology today, some manufacturer order makes special
compact devices for themselves. It is a security way of knows how and it makes
difficulty for maintenance of lacking replaced devices on the market.
2.1.2 Power amplifier:
There are many designs to do power amplifier. The most important for
designer is getting optimum design which must follow the devices appearing on
the market. We propose some schemes for choice
a. Half – bridge inverter
Unfiltered
Output
Filter
45
Filtered
Output
With this scheme, which gives high quality of waveform, high transmitting speed
waveform has not been split of in channels. It requests transistor devices Bi–pole,
which can stand in high voltage.
b. Full – bridge inverter
Unfiltered
Output
Filtered
Output
Filter
Speed of change has shape of half – bridge but output waveform was
channel split off. This circuit is well for big power range, allowing using lower
voltage devices and saving energy. But UPS devices are suitable for this circuit
2.2 Principle Scheme: consists of:
-
Sine wave oscillator board
Modulator board
Chopper board
Power amplifier board
3. Definite principle of operating block:
3.1 Circuit creates sine wave
IC 555 oscillates to create square wave 50Hz to make clock pulse IC 2
(4520), this pulse is taken carried out by gate Q0 of IC2 with frequency 20kHz. It
drives modulator and recorrect waveform. Output gate Q1 of IC2 makes pulse
clock for IC3 to create pulse 800Hz on output gate Q3 and pulse 50Hz is taken out
at sixth pin of IC4, which is a signal to drive IC6.
Op-amp 1 amplifies feedback Voltage from load past to fourteenth pin of
IC6. At pin14, 13, and 12 of IC6 can be display switch, when pin 14 links 13 opamp 2 amplifies IC5 has function to decode BCD 3 line into out 8 lines
combining op-amp 2 to create step sine wave which has amplitude Vp – p = 12V.
3.2 Modulator and channel splitting off (see above principle diagram)
46
IC1 recorrects step wave form to become standard sine wave 50Hz. IC2 takes
out feed back signal from load to reference and compensate with standard sine
signal then creating distortion sine wave as following chart:
IC 3 Osculate to create triangle pulse high frequency 20kHz. This signal goes
together detective sine wave into IC4 IC5 to modulate and channel splitting of A
and B channels which driver 2 power amplifying channels.
III. TECHNOLOGICAL PARAMETERS:
DC input voltage: 9V – 14.5V
distortion rat < 3 %
AC output voltage: 220C AC ±5%
P = 1000W (if overload 1500W, Inverter stands 1.5s and overload to 2000W to be
50ms)
Stable frequency f = 50Hz ± 0.5%
47
REGIONAL TRAINING COURSE ON ‘INVERTER TECHNOLOGY” 16 -20 October, 2000 HCM City Vietnam
LESSON 6
COMPUTER DESIGNING OF INVERTER
I. INTRODUCTION:
Designing with the support of computer has developed so long, it assists us to save
much of time. Design with the support of computer reach the high exactness if being done
by hand it is very difficult to reach, it is the tool for quick design. One of the works,
which the electronic worker should do well, is to draw the printed circuit board to weld
and install all kinds of electric circuit. If having to do this work in craft there will be a lot
of restrains. Presently there have been a lot of software running on computer which can
be in charge well this work.
I.1 Software used to design electricity, electronics.
The software which are used to design the electronic circuit there are many,
normally they combine in couple to be a group that is Orcad/SDT for Schematic design
tool called SDT, to be used commonly with Orcad/PCB to compare and create the
premise for Orcad/PCB when establishing the Printed Circuit Board called PCB. It
means that Orcad/PCB will base on the draw of Orcad/SDT to design automatically
the circuit lines, location of the accessories in order later to give a printed circuit board
in the preeminent manner.
It can stipulate the names of the following software:
- Software: PROTEL-AUTOTRAX OF AUSTRALIA.
- Software: CIRCUIT MAKER which is the computer program for drawing design - imitation of the electric circuit running on WINDOWS.
- ULT CAP SCHEMATIC DESIGN TOOL.
- ULT PAK of Lab Center.
- SMART.
- QUICK ROUTE running on the media of Windows.
- Easy Professional with the sub-program.
* Pulsar for imitation.
* Analyzer for analysis and imitation of the linear circuit.
* Z match for analysis of the Smith diagram in high frequency.
I.2 Software used in Vietnam
There are a lot of software lists, but we collect Orcad due to the following reasons:
- Orcad imported into Vietnam so long, there are many users therefore it has been
propagated widely.
- There are so many software in the market, easily for set-up.
50
--
- Orcad does not require about the structure of machinery. It can run on IBM, PC
XT, AT Computer or relevant circuits suitable with IBM.
In the field of electricity and electronics the software of ORCAD for designing
electronic circuit, this software settles for two basic matters for making the electric
drawing that is Orcad STD-Schematic Design Tool and designing Orcad PCB Printed
Circuit Board but this software is just in the form of drawing with a preeminent design
to automatically run the networks to connects the accessories with each other.
In order to calculate the design of the electronic circuit we should use further
PSPISE. It has the effect to settle the mathematics for circuit theory.
Capacity of Orcad is also very strong:
- To have capacity for automatic and manual design.
- To have a big library.
- It can be revolving and symmetric partially.
- It can be elastic the connecting wire and bus when moving the objectives.
- It can move and wipe the objectives or blocks.
- It can carry out repeating the orders quickly.
- It can display the squared net.
- There are 05 launching levels.
- The user can foist over 100 adding-up orders.
- Not to limit the classified drawings.
- It can display directly the directories of library.
- Statement can set up in horizontal line and it can set up in vertical line.
- It can print on the paper of size from A to E and there are a lot of particulars you
will refer further.
For the old software Orcad running in the environment DOS therefore if wanting to
use it we should study some orders, nowadays we have had Orcad running in the
environment of Windows therefore the use is easier.
II. DESIGN:
II.1. Design of Inverter.
We will use the software to draw Electronic Circuit: Orcad/SDT in order to carry
out drawing 01 simple Inverter.
In order to be able to draw the electric circuit of Inverter by computer we should
understand function and usage of the orders in menu:
Again
Block
Conditions
Delete
Edit
Find
Get
Hardcopy
Jump
Library
Macro
Place
51
--
Quit
Repeat
Set
Tag
Zoom
After appearance in the left corner of the screen a menu board is arranged to
lengthwise. There are three ways to develop the orders in Menu as follows:
1- To press the key of the initial character of that order.
2- To use the arrow key to move the light bar to the order which we want to call and
press Enter key.
3- To use MOUSE to move the arrow and order which we want to call and to click
the left knot of MOUSE.
4- A lot of main orders in Menu with the subordinate orders and various effects.
From subordinate Menu, when wanting to return main Menu, press ECS key until main
Menu re-appears (or to click the right knot of Mouse).
II.2. The design steps of Inverter.
II.2.1 Design of block diagram:
Inverter is the machine to transform electricity from DC to AC so it should have
the frequency oscillator 50Hz, this signal need to be sufficiently big to excite for the
capacity of transistors together with transformer (to excite for these transistors to
turn off/on to the rhythm 50Hz) to create the secondary rate of the revolving voltage
transformer therefore in circuits should have the impulse amplitudes rating between
primary and secondary rate of the transformer output depending on the DC voltage
input from the said conditions we can construct the block diagram of an inverter as
follows:
Block diagram of Inverter:
1
2a
3
4
5a
6a
LOAD
2b
5b
6b
7
52
--
Block 1: Multi-harmony oscillator or oscillator outputting a rectangular 50 Hz
impulse.
Block 2: Single circuit stabilizer, used to create an impulse amplitude for each halfperiod of excitation. It is possible to control amplitude by means of
feedback from block 3, 4.
Block 5a, 5b: Excitation cascade for the power output transistor.
Block 6a, 6b: Power transistors, connected depending on the out put power.
Block 7: Consists of under-voltage and over current protections and an accumulator
charger.
LC: Output filter (AC).
From the said block diagram we commence to design the electric circuit.
Block 1: Oscillator creating Q, Q:
In order to create two signals of opposite phases for frequency 50Hz we have
more various ways, we can use the oscillating circuit to combine between transistors
and accumulator, inductive wire, resistance, or usage of IC 555, but these circuit
should be settled in stability the complex frequency therefore I see that we can use
IC4047 to make the oscillating circuit and also dividing frequency, we have the
signal in the position 13 with frequency 100Hz divided into 50Hz to position No.:
10 and 11 but opposite with the remaining phase. So, in order to draw the said
circuit we commence the following steps:
Step 1: Drawing IC
a- Pressing Enter for three times to call main Menu
b- From main menu - collect Get
c- From the Get dialog line, to type 4047 and press Enter
on the screen appearing symbol IC
d- To use Mouse or arrow to move the symbol to the location where you want to
set-up and press P key. The symbol will change the color. To move cursor out the
location for continuity to call other accessories, to press <ESC> key to escape
and Enter to return main Menu.
VCC
Y
U1
Y
1
RST
RX
CX
RCC
13
11
10
OSC
RET
+T
-T
AST
AST
Q
Q
4047
9
2
1
5k
VR1
1
+ .33
C1
3
12
8
6
4
5
1
Y
1
Y
+ .1
C2
1
Y
Step 2: To draw resistor, rheostat:
53
--
10k
R1
a- From main Menu to call Get
b- From the dialog line to type into Resistor or R and Enter. The screen appears
the symbol of resistor and subordinate menu
c- To use mouse or arrow key to move the symbol to location where needing to
locate and pressing P key, the symbol will change the color in case wanting to
rotate the symbol we press R key (Routate) to rotate the symbol and to press P
key for location
d- To move cursor out the location to call continuously the other accessories. To
press ESC key to escape and Enter to call main Menu.
Step 3: To draw Vr
a- From main Menu to collect get
b- From the dialog line to call Get, to type into Vr and Enter.
The screen appears the symbol of rheostat and subordinate menu
c- To use Mouse or arrow key to move the symbol to the foot of R and press P
key. The symbol will change color, if needing to rotate the accessory to press R
key
d- To move cursor out the location to call continuously the other accessory.
4/. To draw accumulator C1, C2.
a- From main Menu, to collect get
b- From dialog line Get, to type into Cap and Enter.
The screen appears the symbol of accumulator and subordinate menu
c- To use Mouse or arrow key to move the symbol to foot 1 and 3 of IC to press
key (when needing to press R key to collect the characteristic pole of the
accumulator) to press P key the symbol will change color
d- To use Mouse or arrow key to move the symbol to foot 5 of IC to press P key
the symbol will change color (when necessary to press R key to collect
characteristic pole of the accumulator).
Step5: To draw Mass of accumulator and IC
a- From main Menu to call Get,
b- From dialog line Get, to type into GND power and Enter. The screen appears
the symbol mass and subordinate menu
c- To press arrow key or Mouse to move the symbol to the foot of IC
d- To press P key to confirm. The symbol will change the color
e- To move cursor out the location to call continuously the other accessories, to
press ESC key to escape and Enter to return main Menu.
Step 6: To mark Vcc
a- From main Menu, to collect Place. A subordinate menu appears
b- To collect power. The screen appears symbol Vcc at the location of cursor and
a subordinate menu
c- To use arrow key or mouse to move the symbol to any location near IC and to
collect place (pressing P key) the symbol will change color
54
--
d- To move cursor out the location to call the other components, to press ESC to
escape and Enter to return main menu.
Step 7: To draw circuit line:
a- From main menu, to collect Place to appear subordinate menu
b- From subordinate menu, to collect Wire or BUS or Dashed line (accordingly)
and appear a order line. Begin Find jump Zoom Escape.
c- To use Mouse or arrow key to move cursor to the point for commencing
drawing. For example to draw the line connecting the feet 9, 12, 8 and mass,
to locate cursor at the foot No. 9 of IC and to press <B> key (begin > the
screen appears the order line. Begin End New Find Jump Zoom escape
d- To use Mouse or cursor to draw circuit. When drawing a white line appears
following the location of cursor moving. (To connect to foot 12, foot 8 then
connect mass located before that), to press key <End> the drawing line will
change color
e- To press key ESC to escape and enter to return main menu
f- To repeat the practices from a to e to draw the other circuit lines
Step 8: To draw the point connecting circuit:
a- From main menu to collect Place appearing subordinate menu
b- From subordinate menu, to collect Junction
c- The screen appears the symbol at the position of cursor and subordinate menu:
place Find Jump Zoom escape
d- To use Mouse or cursor to move cursor to the location which wanting to
collect (for example the cutting point between foot 12 with the connecting line
of foot 9 and mass and to press P key the symbol will change color.
e- To continue moving the symbol to point of foot 8 to cut with the connecting
line between foot 9 and mass and to press P key the symbol will change color.
f- To move cursor out the location to press ESC key to escape and Enter to return
main menu.
Step 9: Remark the exit and entry port of the circuit:
a- From main menu, to collect Place to call subordinate menu
b- From subordinate menu, to collect TEXT
c- From question <Test?> to type into oscillation and Enter the screen will appear
the word oscillation at the location of cursor and order line. Place Orientation
value larger smaller find Jump Zoom escape
d- To use arrow key or Mouse to move the word to fixed location and press <P>
key. Then to move cursor to the other location. To press ESC to escape and
Enter to return main menu.
II. 2 Save of drawing
In order to save the drawing, to carry out the practices as follows:
1. From main menu, to collect Quit to call subordinate menu.
55
--
2. From subordinate menu, to collect Write to file.
3. From the dialog Write file? To type into the name which wants to name for the
drawing in attachment of the enlarging part and Enter the drawing save into an
information book.
Note * If calling not correctly the name of accessory, in same screen it will
inform the words <NOT FOUND>. Therefore, if not to understand clearly what the
accessory wants to call, from the dialog Get? To press Enter key to call library.
From the dialog <Which library?> to collect Device.Lib. to collect continuously
Serene order the list will appear for reference.
* Or from main menu to call Library, a page of item listed the names of
component concerning the drawing, we can refer and collect correctly the names of
the desired components.
56
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