Hey everyone
i'm working on a small project , its about controlling speed of a brushed dc motor using 4 quadrant chopper ,
what i don't understand is how to control the speed of the motor when its acting like a generator (the shaft of a DC motor is turned by an external force).
This is an unusual requirement - what exactly are you trying to do ? A little more detail about the objectives might help in getting a correct solution.
Hey everyone
i'm working on a small project , its about controlling speed of a brushed dc motor using 4 quadrant chopper ,
what i don't understand is how to control the speed of the motor when its acting like a generator (the shaft of a DC motor is turned by an external force).
If you actually apply an external torque rather than drive the motor with fixed speed, there's no principle difference between motoric and generatoric mode. You control the speed by setting the motor voltage. That's what every motor inverter or DC chopper involving recuperation does, in so far I don't think it's unusual.
In a H-bridge the voltage is set by the PWM duty cycle. But this does only work with a correct PWM modulation scheme involving synchronous switching. Some "poor mans" PWM schemes found in DIY projects don't work in generatoric mode.