Inverters are the device which converts DC (direct current) to AC (alternating current), and gives High woltage and current from low power battery source.
Inverters are very helpful to operate electrical appliances during power cut or shortage, Inverters can be classified based on the output terms like, Square wave, Modified sine wave and Pure Sine wave output Inverter.
The square wave inverter are very simple and easy to make but that is not suitable for sensitive Electric appliances, Modified sine wave inverters are gives output as close as to the sine wave but not pure as much we have receive from wall outlet. PWM (Pulse Width Modulation) signal based inverters are produce output as pure sine wave and it can be used for any electric appliance that meets the inverter output range.
Simple and powerful PWM inverter circuit diagram designed with IC SG3524 (Regulating Pulse Width Modulator) gives upto 230V AC from 12V DC supply.
PWM Inverter Circuit diagram
Construction and Working
This Inverter circuit contains three stages,
- PWM Switching Pulse Generator
- Switching Device
- Step up Output Driver
The PWM switching pulse generator is the main part of this circuit, which is responsible to produce PWM pulse according to the sine wave reference . The IC SG3524 gives fixed frequency PWM that can be varied by RT and CT element values.
Output from Emit1 and Emit2 pins are directly fed into Switching device that is constructed by N channel MOSFET IRFZ44, the Q 1 and Q2 are drive by Emit1 output. Q3 and Q4 MOSFET are drive by Emit2 output from SG3524.
The step up Output driver contains a transformer 230V primary to 12-0-12V secondary with 2 Amp current rating and this transformer connected in Reverse to step up the voltage output. Sample output is taken by the small circuit to give the reference feedback to PWM regulator SG3524.
- Change the RT and CT value to get required output.
- Use Heat sink over the MOSFETs