Motor Drive with Higher than neccessary DC Bus

[digi001]

Are there any complications for the design of a 3 Phase AC Induction Motor controller with a DC Bus that is 2-3 times higher than it needs to be. Example 1000V DC Bus but only 300V Max Motor.

 

[chuckey]

Voltage ratings of switches!! also, you are going to apply 1000V pulses to a motor which is only rated at 300V? You can keep the pulse widths down so the motors power dissipation is kept under control, but then you will have increased switching losses and high frequency high voltages to keep under control. Seems problematic to me.
Frank

 

[mtwieg]

Primary concern would be flashover on the windings. Also, your ripple current will likely be significantly higher, resulting in more losses. Overall efficiency will be relatively poor.

 

[digi001]

what if you use an output LC filter before the motor to reduce the voltage?

---------- Post added at 14:10 ---------- Previous post was at 14:07 ----------

Voltage range of switches shouldnt be an issue. Real experiment would be using 800V DC bus for Motor 0-200V using 1200V IGBT.

 

[mtwieg]

Yes an LC filter will help with ripple, and with overvoltage. But such an LC filter may be very large and costly. It all depends on the specifics of the VFD and the motor in question.