Low Cost Pure Sine Wave Solar Inverter Circuit

Low Cost Pure Sine Wave Solar Inverter Circuit
Cameron DeAngelis and Luv Rasania
Advisors: Prof. Yicheng Lu and Rui Li
Circuit Diagram
Background
q Solar energy is readily available. However, the DC voltage
generated by a solar panel must be inverted to an AC voltage
to be compatible with our electric grid.
q Modern pure sine wave inverters are very expensive, often
ranging above $100.
Goal
q Our goal is to create a pure sine wave solar inverter circuit
while maintaining a low cost.
555 TIMER CIRCUIT
DECADE
COUNTER
IC
H-BRIDGE CIRCUIT
LOW-PASS FILTER
TRANSFORMER
Results
q The circuit will have a 12V DC input from a solar panel and a
120V AC output at 60 Hz.
Research Challenges
q Maintaining a relatively high power efficiency
q Obtaining a pure sine wave output from a square wave input
Methodology
q A clock signal for the circuit will be generated through the use
of a 555 timer IC.
q The clock signal will control a decade counter IC which is
responsible for optimization of the waveform and triggering of
the H-bridge circuit.
q The H-bridge circuit will provide a square wave output similar
to that of a modified sine wave.
q A passive filter circuit will keep power dissipation low while
properly integrating the square wave into a pure sine wave.
q A transformer will be used to achieve the correct output
voltage.
Voltage (V)
q Implementing a cost-effective control strategy for the circuit
Time (s)
q The circuit and obtained 120V 60hz output signal are shown above. Note the signal has
minimal distortion and resembles a pure sine wave.
q Modern sine wave inverters create a very similar output; however at $50, our design is half
the price.
References
[1] http://www.townofmorristown.org/index.asp?Type=B_BASIC&SEC=%7B623F5519-152C-489E-838C
[2] http://ehelion.net/projects/digitalclock/555timer.html
[3] http://www.technologystudent.com/elec1/count1.htm