Pure Sine wave Inverter Implementation Methodology .

Block Diagram

Explanation of Each Block :

1). Square Waves using PWM IC

It is voltage control PWM controller integrated circuits. It is used with Dc to DC converter part to control output voltage and for switching of MOSFETS connect to push pull converter.  Voltage control method use feedback voltage by comparing it with reference value to set duty cycle of PWM. PWM IC has built in MOSFET driver while with microcontroller you have to use MOSFET driver. 

2). Push Pull DC-DC Converter

Push pull converter is like a buck converter but it has two drive winding isolation transformer.It can be used as step up or step down purpose depending on the turn’s ratio of high frequency transformer. It is used to convert 12 volt DC into 311 volt DC which is a peak of 220 AC voltages. It is preferred here because it can handle high power. 

3). FILTER

Push pull converter steps up DC from 12V to 311V which may have ripples so we use rectifier to make output smooth. Push pull topology require smaller filter than other dc to dc converter typologies.

4) SPWM Using Microcontroller and MOSFET Driver Circuit 

I  have generated SPWM using Pic microncontrller which will create a 50 hz sine wave in h bridge circuit. Mosfet driver circuit is used to drive the MOSFET in H bridge as signal generated from microcontroller has magnitude of 5 volt and we need 8 to 12 v signal to drive MOSFET properly so for that purpose we need MOSFET driver circuit .I have used IR2112 for high and low side of Bridge circuit.

5) MOSFET H-Bridge Circuit

In pure sine wave inverter 311 volt is used as input voltage supply from dc to dc converter using push pull topology to H-Bridge .Control signals are generated through microcontroller which drive the MOSFET. H Bridge is used to generate positive and negative cycle of AC voltage. H bridge switches selection also depend on power rating of power inverter

6) LC Filter

Output of H bridge is fed to LC filter to remove harmonics from output. Neat and clean sine wave output can be obtained by using proper LC filter.Single tuned filter has been used that allows only 50Hz to pass