Analysis and Implementation of DSP Based Speed Control of Three

Transcription

Analysis and Implementation of DSP Based Speed Control of Three
ISSN(Online): 2320-9801
ISSN (Print): 2320-9798
International Journal of Innovative Research in Computer
and Communication Engineering
(An ISO 3297: 2007 Certified Organization)
Vol. 3, Special Issue 2, March 2015
Analysis and Implementation of DSP Based
Speed Control of Three Phase Induction
Motor
E.Baraneetharan1, P.Raghuraman2
Associate Professor, Cauvery College of Engineering and Technology, Tiruchirappalli, Tamil Nadu, India
UG Student, Gnanamani College of Technology, Namakkal, India
ABSTRACT: In this paper we analyse the speed control of induction motor in various control techniques and
implement the new controller depends on intelligent techniques. In recent years, the field oriented control of induction
motor drive is widely used in high performance drive system .It is due to its unique characteristics like high efficiency,
good power factor and extremely rugged. These intelligent controllers are used to accomplish the control of preferred
speed. Putting into practise of this processor it is interfaced with embedded system. So as real-time control also
obtained and the total harmonic distortion diminishes fully by this method. This scheme leads to be able to adjust the
speed of the motor by control the frequency and amplitude of the stator voltage. The ratio of stator voltage to frequency
should be kept at constant. Associate to other controller like PID, Fuzzy, DTC control, Single Artificial Neuron
Network (SANN), Single Pulse Width Modulation inverters (SPWM), Constant V/F methods and Hysteresis
Comparators, this method stimulate enhanced operation of preceding modus operandi. By this DSP based controllers
we minimize the switching frequencies, Harmonics and need of filter circuits, 50 – 70 % of resonance frequencies and
over all time response of the controlling strategy.
I.INTRODUCTION
In this paper we analyse the speed control of induction motor in various control techniques and
implement the new controller depends on intelligent techniques. In recent years, the field oriented control of induction
motor drive is widely used in high performance drive system. It is due to its unique characteristics like high efficiency,
good power factor and extremely rugged. By controlling of three phase induction motor various techniques are in
progress. Still we are lagging to control the three phase induction motor in rural areas. The controlling point, level of
voltage and flux will induced other drawbacks in the motor. The efficiency, regulations are getting poor by
conventional techniques. To improve switching speed, rising time, settling time & peak over shoot of the response to be
achieve by our proposed intelligent modules operation. The THD is 75–80% reduced. So as the resonance also
minimized in this technique. The DSP processor (TMS320F28027) is used for our proposal. The accuracy, reliability
and compact of this are better when comparing with other. Induction motors are used in many applications such as
HVAC, Industrial drives control, automotive control and etc., in recent years there has been a great demand in industry
for adjustable speed drives. Recently, Fuzzy logic control has found many applications in the past decade. Fuzzy Logic
deals with problems that have vagueness, uncertainty and use membership functions with values varying between 0 and
1. This means that if the reliable expert knowledge is not available or if the controlled system is too complex to derive
the required decision rules. Development of a fuzzy logic controller becomes time consuming and tedious or sometimes
impossible. In the case that the expert knowledge is available, fine-tuning of the controller might be time consuming as
well. Real time implementation of MATLAB interface for speed control of induction motor drive using DSP processor
is quite new. The aim of this paper is to show the dynamics response of speed with design the fuzzy logic controller to
control a speed of induction motor and to design the real time implementation of MATLAB interface for speed control
of induction motor drive by using DSP processor.
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77
ISSN(Online): 2320-9801
ISSN (Print): 2320-9798
International Journal of Innovative Research in Computer
and Communication Engineering
(An ISO 3297: 2007 Certified Organization)
Vol. 3, Special Issue 2, March 2015
II.BLOCK DIAGRAM
In our scheme, it leads to be able to adjust the speed of the motor by control the frequency and amplitude of the stator
voltage. The ratio of stator voltage to frequency should be kept at constant. The rectifier circuit and inverter
Fig 1.1 Block diagram of DSP based control
circuits are used to give the correct variations of pulse signals to the corresponding PWM generators. MATLAB based
DSP TMS320 series processor is used here to give continues and non varying switching pulses to reduce the switching
losses in the resonance part. We are implemented three phase induction motor for the efficient control of speed in this
trial.
IC Voltage Regulators
Voltage regulators comprise a class of widely used ICs. Regulator IC units contain the circuitry for reference
source, comparator amplifier, control device, and overload protection all in a single IC. IC units provide regulation of
either a fixed positive voltage, a fixed negative voltage, or an adjustable set voltage. The regulators can be selected for
operation with load currents from hundreds of Milli amperes to tens of amperes, corresponding to power ratings from
milliwatts to tens of watts. A fixed three-terminal voltage regulator has an unregulated DC input voltage, VI, applied to
one input terminal, a regulated DC output voltage, Vo, from a second terminal, with the third terminal connected to
ground. The series 78 regulators provide fixed positive regulated voltages from 5 to 24 volts. Similarly, the series 79
regulators provide fixed negative regulated voltages from 5 to 24 volts.
 For IC’s, Micro Controller,
LCD ---------------- 5 volts.
 For alarm circuit, op-amp,
relay circuits ----- 12 volts.
Induction Motor
One of the mature control systems of induction motor is the field oriented control method. The FOC method is widely
used and presents some high standards in modern industrial drives. A continuous trend in IM drives is to increase the
reliability of the drive system. One solution is to decrease the amount of normally used sensors. Because of noises and
other disadvantages the troublesome device in some of industrial drive system is the speed sensor. Therefore, in most
modern IM drives speed sensor elimination is required. Instead of a speed sensor, different methods for speed
calculation are proposed in the literature. Comprehensive reviews of the IM sensor less drives are given, indicating that
some problems with the sensor less control are persistent, so new solutions are still needed. Current work efforts are
dedicated particularly to zero or very low speed range or to very high performance drives. Another problem in electrical
drives is system sensitivity to inaccuracy and changes of motor equivalent circuit parameters. Most of the FOC systems
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78
ISSN(Online): 2320-9801
ISSN (Print): 2320-9798
International Journal of Innovative Research in Computer
and Communication Engineering
(An ISO 3297: 2007 Certified Organization)
Vol. 3, Special Issue 2, March 2015
are very sensitive to that inaccuracy so some parameters should be estimated on-line. Also, robust structures of the
control and estimation schemes are generally researched. The integral part of numerous FOC systems is the stator
current controller. Different methods for current control are presented in the literature. Good results of current control
are reported for predictive current based controllers. In this paper PCC is implemented in the IM speed sensor less
system with field oriented control method. In the FOC system instead of linear PI current controllers, predictive current
controllers may be used. The current control algorithm previously presented was modified by using the observer system
instead of simple load model [5]. With such approach, better results were recorded. To avoid the system complication
for the PCC, the back EMF calculation was integrated to flux and speed observer for FOC IM drive.In this project, new
results as well as the new solution for integration of a motor choke in the current controller are presented. The proposed
drive is speed sensor less and robust on motor parameters changes. The obtained results confirm that the system works
properly without parameters estimation, even in very low speed ranges. Both simulation and experimental
investigations for 5.5 kW IM drive is presented.The project circuit module is shown in above figure. The 230V AC
Supply step- Downed by 12V AC supply by use of step down transformer. The 12V AC supply given to the Bridge
Rectifier.This Circuit has four diode named as D1 to D4 which is responsible for the rectification of 12V AC to 12V DC
supply.
After this rectification the output DC supply given to the filter circuit. For purpose of filter is reducing the Harmonics.
It reduce the Harmonics and given to the voltage regulator. The process of Voltage Regulator 7805, Regulate the 12V
DC into 5V DC supply. Hence this rectified and regulated voltege which operates the DSP Processor
(TMS320F28027). So 5V supply given to the DSP Processor. Normally DSP Processor working at 5V DC supply.
That’s why here we implementing the Voltage Regulator and it regulate the output DC supply through the rectifier.
DSP Processor using a SVPWM Algorithm (Space Vector Pulse Width Modulator).In DSP Processor inputs (VCC) are
given to the voltage regulator output. Another input of DSP Processor (XTAL1, XTAL2) given to the crystal oscillator.
Crystal oscillator is used to given the clock frequency in DSP controller. This DSP Processor Based Speed control of
Induction Motor fully depends or based on MATLAB Programming.
III.
CIRCUIT DIAGRAM
Fig 2.1 Circuit Diagram of DSP Based Three Phase Induction Motor
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79
ISSN(Online): 2320-9801
ISSN (Print): 2320-9798
International Journal of Innovative Research in Computer
and Communication Engineering
(An ISO 3297: 2007 Certified Organization)
Vol. 3, Special Issue 2, March 2015
The output terminal of DSP Processor (PC0, PC1, PC2, PC3, PC4, and PC5) thoroughly connected with driver
system. In This driver system consist of Opto coupler driver’s. Thus the output of a DSP haves 8 ePWM modulator.
For our convenience, here we are use 6 ePWM and it is triggered with the 5V supply from the processor to the Opto
coupler. When the opto coupler receives the trigger the 12V DC supply is drived by Opto coupler by use of Rectifier.
The purpose of this supply is used to give the working process of Opto coupler producing 15V DC output supply. This
output given by the MOSFET for a triggering purpose. The input side of inverter the 230V AC supply is given. That
230V AC supply converted by 230V DC supply by use of Bridge rectifier. At the period of conversion some resonance
losses will occurred, that will controlled by resonance controller (Inductor).
After, this conversion the Single Phase voltage will convert the Three Phase Voltage by the use of MOSFET. Finally,
the output 3Ф 440V is given to the induction motor. In between of this inverter and Induction Motor switching losses
(resonance) will produce that will controlled by resonance controller in each phase.
The induction motor speed rate will feed backed by using of tacho generator. This tacho generator placed on DSP
Processor (PA0). In the DSP Processor PI comparator also used. That willcompare input speed and output speed of a
both MATLAB and Induction Motor. In that have any Variation means it will correct that and run the motor with
preferred speed. That means it will reduce the whole resonance and harmonics losses and give the pure form of Output
speed. Finally, our prospect output of an induction motor will get.
Fig 2.2 MATLAB circuit for our proposal
DSP Processor
The F2802x Piccolo family of microcontrollers provides the power of the C28x core coupled with highly
integrated control peripherals in low pin-count devices. This family is code-compatible with previous C28x-based code,
as well as providing a high level of analog integration. An internal voltage regulator allows for single-rail operation.
Enhancements have been made to the HRPWM module to allow for dual-edge control (frequency modulation). Analog
comparators with internal 10-bit references have been added and can be routed directly to control the PWM outputs.
The ADC converts from 0 to 3.3-V fixed full-scalrange and supports ratio-metric VREFHI / VREFLO references. The
ADC interface has been optimized for low overhead and latency.
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ISSN(Online): 2320-9801
ISSN (Print): 2320-9798
International Journal of Innovative Research in Computer
and Communication Engineering
(An ISO 3297: 2007 Certified Organization)
Vol. 3, Special Issue 2, March 2015
IV.
RESULT
In this system we observed a performance in both MATLAB and Hardware kit. All over that it is flexible for
future enhancement. Experimental results shows that greater Peak Over Shoot, Less Ripples, Good Transient and also
avoid the Total Harmonics Distortion (THD) and Resonance Frequencies. Competently, it will control the Induction
Motor Speed with a perfect controlling operation.
Motor Speed at 1300 RPM
Motor Speed at 950 RPM
Motor Speed at 600 RPM
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ISSN(Online): 2320-9801
ISSN (Print): 2320-9798
International Journal of Innovative Research in Computer
and Communication Engineering
(An ISO 3297: 2007 Certified Organization)
Vol. 3, Special Issue 2, March 2015
What ever the speed which is given as the input to the Real time matlab simulator the processor makes the motor to
revolute at the given constant speed at any various load changes.
This DSP controller can perform large and complex computation with any desired degree of accuracy at very
high speed, easily programmable so they are more versatile. It have better resolution. It eliminates the number of firing
circuits and power electronics components. So fast response & simple to construct. The Efficiency is improved. So we
may isolate the circuit for any other applications also. The rejection of disturbance signals gives more accuracy. The
overall stability of the system is improved sensitively. It is Used as speed regulators. There is a absence of distortion
and ripples. So we may use these controllers for the accuracy of all types of control circuits in remote areas. The time
delay of the circuit is better. Therefore it may utilize for all type of power full loads. Also used in pumps and turbines
for improve the efficiency and in conveyors in all type of industries.
ANALYSIS & DISCUSSION
Time (sec)
S.No
Type of Controller
1. PI Controller
Settling time
Rising time
% THD
Point of view
The PI controller has low
precision of speed regulator
debases the performance of the
whole system.
3.2
1.5
54.42
2
1.2
59.82
0.58
0.48
62.74
4. DTC Technique
0.6
0.4
77.53
5. SPWM Technique
0.6
0.4
83.74
6. V/F Characteristics
2.5
1.5
50
7. Hysteresis Comparator
1.5
1.3
61
0.45
0.40
52.61
2. PID Controller
3.
8.
Fuzzy Logic Controller
(FLC)
SVPWM Inverter With
DSP Based Controller
V.
Time
consuming
is
high
comparing other controllers &
techniques
Time consuming retuning even if
applied to a similar plant in other
location
It needs an external DSVM
technique with two equal time
intervals and 12 new voltage
vectors.
(DSVM = Discrete Space Vector
Modulation).
Resonance Frequency Losses will
Highly Induced
This V/Fcomparator producing
time delay Highly
Hysteresis comparator technique
which is using sensor less control
of BLDC motor drive of an
automotive fuel Pumps only.
More compact for all type of
loads in different swift.
CONCLUSION
The progress in science and technology is a non-stop processes a new things and new technology being invented. As
the technology grows day by day, we can imagine about the future in which thing we may occupy every place. The
proposed system based on DSP processor is found to be more compact, user friendly and less complex, which can
readily be used in order to perform. Though it is designed keeping in mind about the need for industry, it can extended
for other purpose such as commercial and research applications. MATLAB 12b is used for better simulation and make
to simulate the process effectively. This is more suitable for three phase induction motors with 2 HP, 440 v, 50 Hz
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ISSN(Online): 2320-9801
ISSN (Print): 2320-9798
International Journal of Innovative Research in Computer
and Communication Engineering
(An ISO 3297: 2007 Certified Organization)
Vol. 3, Special Issue 2, March 2015
ratings. This is implemented and got effective result in Hardware kit shown in pictures. Due to probability of high
technology (DSP Processor) used this Analysis and Implementation of DSP Based Speed Control of Three Phase
Induction Motor is fully software controlled with less hardware circuit. The feature makes this system is the base for
future system.The principle of the development of science is that “nothing is impossible”. So we shall look forward to a
dazzling and erudite world.
REFERENCES
1.
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2. P.Tripura and Y.srinivasa Kishore babu, 2011. Fuzzy Logic Speed Control of Three-Phase Induction Motor Drive, Guntur. Vol-60, ISSN:
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