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Open loop regen braking

Posted: Sep 28 2019 9:07am
by johnrobholmes
I'm doing some thinking about how regen braking can be implemented without a current sensor. For simplicity, i consider an h bridge. Typically, it seems that regen braking is done by reversing the bridge from state A to B, but without a current sensor it will reverse motor direction once bemf is extinguished.

My thought is that we could have a "dumb" regen brake that bounces between low side or high side fets in the on state (probably high side with low side body diodes conducting?). With some dead time in between to prevent recirculating the current within the bridge.

Thoughts or resources would be appreciated!

Re: Open loop regen braking

Posted: Sep 28 2019 9:16am
by johnrobholmes
My Google fu of ES finally resulted in this thread from Justin which suggests that bouncing the low side fets will get my result without knowing motor or current direction. Only half the strength of a full brake, but I'm attempting to do this blindly without feedback or modeled motor parameters.