# Please need help for sine wave inverter.

#### Muzamil Farid

Joined Nov 24, 2015
4
I am working on sine wave inverter and i really need serious help,It will be heavily appreciated, I am controlling H-bridge(High side P channel,Low side N-channel) via SPWM signals and 50HZ Square Pulses.The first leg controlled by SPWM and other leg controlled by 50HZ square waves, I am confused about the functioning of P-channel Mosfets, How are they conducting?.What is the criteria of conduction? The source of high side p mosfets is 12V dc to be converted to 220V,50Hz sine wave,My confusion is that output distorted Sine wave will have a peak of 12V?. After implementing on proteus I am getting 0v between two outputs of H-bridge.

#### Dodgydave

Joined Jun 22, 2012
9,876
So am i confused, your using square waves making a sine wave, lets have a circuit diagram please....

#### Muzamil Farid

Joined Nov 24, 2015
4
So am i confused, your using square waves making a sine wave, lets have a circuit diagram please....
Thanks for the reply, Actually i surveyed on the internet and found the designs using 50HZ Sqaure waves on the right leg of bridge, I am obtaining Sine waves from SPWM control signals,The only explanation i could find of using 50HZ Sqaure wave was that it controls polarity and PWM signal controls amplitude of output wave,I

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#### alfacliff

Joined Dec 13, 2013
2,458
yes the output will be 12 volt square aves. a transformer is used to step up the voltage to the out put you want.

#### Dodgydave

Joined Jun 22, 2012
9,876
Is L1 a transformer?, if so the secondary winding is not drawn, that will step up the voltage to 220V ac, or whatever its designed to give out, dont see the point of C1 .

#### Muzamil Farid

Joined Nov 24, 2015
4
Is L1 a transformer?, if so the secondary winding is not drawn, that will step up the voltage to 220V ac, or whatever its designed to give out, dont see the point of C1 .
L1 is the inductor used with C1 as low pass filter to remove unwabted harmonics from output

#### Dodgydave

Joined Jun 22, 2012
9,876
L1 is in the wrong place, it should be in series with the positive supply.