Thread: Power MOSFETs
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Old 14th May 2019, 11:24 pm   #51
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Default Re: Power MOSFETs

Originally Posted by M0FYA Andy View Post

I'm not sure what the way forward is, other than to stick with rotary machines...

Ah, the quest to replace the rotating machine with an electronic equivalent.

I faced exactly this issue wanting to test the simple alternator & dynamo regulators. The PWM in these results from the fact that the regulator becomes enclosed in a feedback loop with the electromagnetic properties of the particular rotating machine, including the hysteresis and delays that occur at the output when the field voltage is manipulated.

So outside this environment, on a bench, only simple threshold tests can be performed on the regulator module, you cannot know its operating frequency. This is one of the many reasons why modern versions went to fixed frequency pwm, there were other reasons such as needing LRC (load response control).

In the end I designed and built an "alternator and dynamo emulator" to test regulators fully without the need for the rotating machine. As far as I know it remains the only one published anywhere. Apparently there was one in the USA, but there was nothing technical published on its operating theory.

The article is here:
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