Hello
I am working on a 230V inverter from a 350-450V supply voltage. For now, I am only working with 30V while I am configuring the dsPIC and the hardware.
The dsPIC makes the right PWM. For now, I put a large 200ns dead time between the PWM signals. Unfortunately, I cannot explain the short-circuit from the power bus (The logic circuits have their own power supply). When I try an half-bridge alone, I don't have any problem, the gate and output signals are ok. But when I want to use the full bridge, the problem occurs. The problem disappears when I disconnect the LC filter. I don't have any load for now, except the output filter.
In these first tests, I have used the converter in an open loop configuration with 50% PWM duty cycle.
Do you have a clue to help me ?
Please find attached the schematic below. "Iout_bridge" outputs on a current sense resistor connected to ground.
There is no series inductance (just a common mode choke) and there are capacitors at the ouput . For sure one can expect high current peaks with high dV/dt edges.
Do you really use 0603 capacitors and 1206 resistors as snubber for 450V DC? If so, then I expect the next problem...