Hi SgtWookie,

Just thought you'd like to know that the 3 phase inverter finally turned the alterantor!

I used some more heavy duty gate drivers capable of delivering 2A to the gate.. left in the 100Ω gate resistor and it worked perfectly.. When I applied 12v to the rotor of the alternator, it stopped dead though... but that turns out to be a too high frequency (450hz)... I experimented and found that 25hz works... I'm not sure if thats the optimal frequency but hey maybe its got something to do with voltage/frequency... but I'll have to go and research that a bit.

Thankyou so much for all of your help... the car headlamp setup was an inspiration... it was invaluable!

Cheers
Shaun

 

Hi SgtWookie,

Just thought you'd like to know that the 3 phase inverter finally turned the alternator!

Great news!

I used some more heavy duty gate drivers capable of delivering 2A to the gate.. left in the 100Ω gate resistor and it worked perfectly..

Well, if the gate drivers are capable of delivering 2A, then you really should reduce the series gate resistors to take advantage of their improved current carrying capability.

When I applied 12v to the rotor of the alternator, it stopped dead though... but that turns out to be a too high frequency (450hz)...

You're not changing the direction of current through the rotor, are you? It should just go one way, with a "flywheel" diode to let the current continue flowing when the MOSFET cuts off.

I experimented and found that 25hz works... I'm not sure if thats the optimal frequency but hey maybe its got something to do with voltage/frequency... but I'll have to go and research that a bit.

It's been a good while and many other projects between, and I'm afraid I don't remember the particulars. It would help if you'd post updated schematics and explanations of what signals you had going where.