I am a student working on a university project. I need help figuring out how I can supply 18 PWM signals to 18 gate drivers, in a 3-phase inverter.
The inverter is built up of 3 half bridges, with 6 transistors per half bridge, 3 on the high side and 3 on the low side.
The gate driver takes a simple HIGH/LOW signal, and has a built in signal inverter for low side. The switching frequency is at 24kHz. I want a I/O expander or a slave microcontroller to supply the PWM, as the main controller sits quite a bit away from the 3-phase bridge. My wish is to turn off some of the transistors when the inverter is running at a low load to improve efficiency.
As far as I am aware, using GPIO pins is out of the question, so I need dedicated PWM pins, my issue is that I don’t have enough PWM outputs.
I have been looking at I/O expanders, but the vast majority I found only gave GPIO. I have also been looking at LED drivers, but I am not sure if they are the best choice.
Another option might be using AND gate logic, supplying the PWM to one input, and the ON/OFF command to the other input. This way I might be able to reduce the PWM to 6 outputs.