Originally Posted by howardcano

If the battery ESR and MOSFET on-resistance are sufficently low, then the voltage output from each ESC terminal will be at either zero or the full battery voltage while the MOSFETs are on. They essentially act only as switches. At full throttle, they are on for the entire length of each commutation phase (no PWM).



The motor back-EMF is sinusoidal for each phase. Commutation makes this appear to the battery as a rectified 3-phase signal (DC with the tops of each sinusoid superimposed). The current has a similar appearance, but with maximums where the back-EMF is minimum (disregarding other effects from inductance, etc.) Again, this is for full throttle (no PWM).



Putting caps in parallel does divide the ESR for the combination. But this usually won't result in any perceptible increase in "punch" (power), as the commutation frequency is too low for the caps to supply current for a significant length of time.