# High switching frequency



## edin (Sep 16, 2012)

Hey all,

I'm trying to source a controller for a ~50kW peak brushless DC motor with 8 pole pairs. We want to run it up to ~5000rpm, and I'm having trouble finding a controller that will handle a switching frequency that high. Sevcons go to 500Hz, which means I'm limited to 3750 rpm. Anyone know of a controller that can handle 500A+ and a high switching freq?

Thanks!
Eric


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## major (Apr 4, 2008)

edin said:


> I'm trying to source a controller for a ~50kW peak brushless DC motor with 8 pole pairs. We want to run it up to ~5000rpm, and I'm having trouble finding a controller that will handle a switching frequency that high. Sevcons go to 500Hz, which means I'm limited to 3750 rpm. Anyone know of a controller that can handle 500A+ and a high switching freq?


Hi edin,

First off, switching frequency generally refers to the frequency of modulation and for VFDs can be anywhere from 2k to 20kHz. What you're concerned with is called the fundamental or output frequency. Industrial VFDs will easily go to 120 Hz; some to 300 Hz and a few to 400 Hz. A few high end versions can do 800 or maybe 1200 Hz in V/f only. It looks like maybe Sevcon and some other EV drive controllers (?) can do 500 Hz. I don't know of any drive capable of higher.

How about posting photos and specs for that 50 kW 16 pole motor?

Regards,

major


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## edin (Sep 16, 2012)

Oops, sorry for my mistaken terminology. Still very much a n00b when it comes to this stuff. No photos of motor yet...they're currently being designed and tested, so no hard specs either, unfortunately.


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