Transformerless inverter using SG 35xx

[ATIKU]

Pls I need your help

1.Pls help me check the transformerless inverter circuit using SG 35xx will it really works in real practical

2. One of my mentors said it will work but by changing the bootstrap input to 12v and when I change it to 12v my AC output is around 82v instead of 230v AC

Pls help am confused

 

[BradtheRad]

Located in the schematic is an H-bridge, made from bjt's or mosfets or both. Its power source is 300 V via batter ies. It's unclear what bias voltage turns those components On & Off. To accomplish that purpose bias needs to be at the correct level during one-half of the cycle, and correct level during the other half. All but one appear to be N-devices. N-devices require a different biasing schedule than P-devices. At certain positions in your schematic, a P-device may be a suitable choice rather than an N-device. I could be wrong.

 

[FvM]

There are several issues with the circuit. Obvious point is that Q1 and Q2 are shorting UC1525 outputs and respectively low side gate voltage. Using 300 V DC bus as bootstrap supply will immediately destroy transistors in a real circuit. High side gate drivers must have high voltage rating, presently used MPSH10 are low voltage RF transistors. Why not using bootstrap driver IC?

I would also suggest to draw the circuit in a regular H-bridge form, I guess many readers don't even recognize high- and low-side transistors.

 

[FvM]

Besides generating correct gate drive voltage levels, it's also necessary to provide dead-time between high and low side gate activation.