single phase inverter

[fadhel93]

I have a project that inverts DC to AC. I have a problem as I increase the load, ripple occure in the DC bus voltage and the output signal become distorted.


this is the circuit diagram

 

[KlausST]

Hi,

This is only a snipet of a schematic. No information about bulk capacitors, power source, current, freqzency....

And there is no question. What do you want to know?

Klaus

 

[fadhel93]

The power source is 70v from DC to DC converter, and the mosfet drivers are fed with 20KHz PWM from mbed microcontroller, the Inverter is designed to handle 100watt, the question is why when I increase the load, the output signal is distorted. and ripple occure in the DC bus voltage (even when I supply the inverter from bench power supply)

 

[BradtheRad]

What pattern of Ampere waveform is drawn from your DC supply?

When the power section draws large bursts of current, many times per second, it is liable to create ripple on the supply to the control section.

It might help you diagnose the trouble if you feed separate power leads to the different sections.

Also, consider installing a large value capacitor across the power leads where they connect to your circuit board.

 

[Orson Cart]

your DC source is not sufficiently powerful, you need caps across your bridge...