Yes Rony ....it is absolutely correct - I wanted regen braking and it was the reason why I made such a circuit. And it works 100%

I started the thread to get help for a full bridge motor controller because I use a relay for forward and reverse, but the drop out of the relay is about 21V and draws approximately 380 mA, so I vill replace the relay with a full bridge controllers.

I was hoping that someone had a good circuit as they had good experience with.

Most of the thread was about the circuit that I have made and which works very well. but many had comments that it should be made in a different way ... I do not understand why ? - it works as I want it !!!!

 

You can lay the blame on me for taking your thread off on a tangent. I learn from my mistakes.

I learned why a logic-level P-channel MOSFET was replaced by an N-channel MOSFET on the high-side driver.

I also learn why the lower MOSFET is required:

1) to charge the bootstrap capacitor,

2) to provide regenerative braking,

3) to provide a freewheeling diode.

 

YES Rony .... it is absolutely correct .....that was the reason why I made this circuit because I wanted regen braking.

I started this thread because I wanted some help to make a full bridge moror controls, I now use a relay for forward and reverse, but the relay has a drop out of about 21 V and uses about 380 mA - therefore I will replace the relay with a full-bridge controls

Most of the thread has been about many commented on my motor controller and proposed to make it in a different way

I do not understand why when it works 100% as I want it and have now done so for more than one year ???

So back to my thread. Does anyone have experience with a good full bridge motor controller?

Tonny

 

You can lay the blame on me for taking your thread off on a tangent. I learn from my mistakes.

I learned why a logic-level P-channel MOSFET was replaced by an N-channel MOSFET on the high-side driver.

I also learn why the lower MOSFET is required:

1) to charge the bootstrap capacitor,

2) to provide regenerative braking,

3) to provide a freewheeling diode.

It is quite ok ... we all learn every day .... it's the meaning of life


Tonny

 

Please explain how a half-bridge can provide regenerative braking?
When the low side switch is on, the motor is SHORTED, it will stop, but no regeneration is possible.

 

Scratch the term regenerative braking before someone starts nitpicking.
We all know what we're talking about. Resistive braking might be the better term.

Edit: Oops, someone beat me to it.

 

It is hard for me to explain, but think inductive kick first then which way current flows then inductive kick again.

 

I had a dream about how to show it. Attached is a simulation showing about 75% throttle on level ground changing to 50% going down a hill.
So the motor starts and the current builds up in the motor and your humming along. The bottom FET is clamping the inductive kick from the motor, but that's cool it's in the same direction to drive the motor.
Once at the top of the hill the throttle is reduced to 50%. Now the bottom fet is on long enough to brake the motor and current flows in the opposite direction due to the back emf. When the bottom fet turns off the voltage on the driven terminal spikes plus due to the inductive kick from the brake. This is what is fed back into the battery.