Common Mode Voltage from a PWM drive question
Common Mode Voltage from a PWM drive question
(OP)
I read the comment in an article "common-mode voltage arising from the non-sinusoidal current produced by an inverter's power-switching circuitry.".
This doesn't make sense to me. It's the current that produces the common mode voltage? I thought it was the inverter switching the voltage on and off that produced the common mode voltage.
This doesn't make sense to me. It's the current that produces the common mode voltage? I thought it was the inverter switching the voltage on and off that produced the common mode voltage.





RE: Common Mode Voltage from a PWM drive question
RE: Common Mode Voltage from a PWM drive question
Usually motor providers ask to use a filter to limit this.
Also using suitable special ferrite-kind rings for the 3-phase output limit this problem.
RE: Common Mode Voltage from a PWM drive question
But common mode voltage wouldn't be a problem on it's own. Unfortunately you can never avoid the parasitic capacitances and hence you will also see common mode currents flowing.
A sinewave filter intended to get sinusoidal currents will also adress this topic, but at a big penalty in cost and efficiency. Common mode issues can be adressed by much more simple filters.
RE: Common Mode Voltage from a PWM drive question
Gunnar Englund
www.gke.org
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Half full - Half empty? I don't mind. It's what in it that counts.
RE: Common Mode Voltage from a PWM drive question
That's a very nice explanation - thanks for sharing.
dpc
David Castor
www.cvoes.com
RE: Common Mode Voltage from a PWM drive question
Thanks for all the help!!!