PWM motor controllers, Half bridge, no bridge, etc
So I have been experimenting with PWM and motor controllers and I now have some questions.
I understand an H-bridge is good for reversing an electric motor. But what is the main purpose of an half bridge? Is it to get forward motor voltage and freewheeling?
I ordered a driver chip but the wrong one came so I was unable to test out a half bridge using 2 N channel fets. So I hooked up a large DC fan from Vcc to the Drain of the mosfet and was able to get a variable motor controller up to about 23amps at 16v (I didn't run it and harder as my fuse is 25Amp).
I only had a single 3A diode in parallel with the motor to help protect the mosfet. I am assuming this is required for power mosfets?
So my next question is. What is wrong with just using a low side mosfet for running this motor? Do I need a high side to provide freewheeling, braking, or is that for protecting the low side mosfet?
The mosfets are 75v 75amp continuous rated and I have a few I'd like to parallel to test a 200 amp motor at 36-48v but I want to understand whats going on better so I don't destroy expensive mosfets.
Well, if it's just a single half-bridge, one big advantage is the ability to physically place it away from the other half-bridge so that you can use physically larger heat sinks.
If it's a full H-bridge IC, the power rating will be much smaller than a half bridge; there just is not sufficient area available to dissipate the heat.
If you have a question, please start a thread/topic. I do not provide gratis assistance via PM nor E-mail, as that would violate the intent of this Board, which is sharing knowledge ... and deprives you of other knowledgeable input.
|bridge, controllers, half, motor, pwm|
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