Modeling motor control

[Ether]

Originally Posted by Al Skierkiewicz

Neither controller provides a discharge path during the OFF period. It is this phenomena that gives the Jag it's apparent linear response.

The FETs in both the Tan and the Black Jags have a zener diode to provide a path for the current to keep flowing through the motor during the OFF portion of the cycle.

http://www.chiefdelphi.com/forums/sh...30&postcount=9

The Jag's linear response is due to its higher switching frequency, which creates an effectively flatline current waveform whose amplitude (which is the average since the wave is flat) varies linearly with the voltage duty cycle.

The Vic's slow switching frequency allows to current to decay to zero during the off portion. The average value of this sawtooth waveform does not vary linearly with the voltage duty cycle, so neither does the motor torque.