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Participant

Join Date: Feb 2007
Posts: 3

New Motor Technology need a Drive

02/14/2007 11:57 AM

I have built a large air core motor from technology licensed to me. The motor only has I2R losses in the windings and hysteresis, iron core, eddy current and short circuit current losses have been eliminated. I need a drive (preferrably a 3 phace IGBT brushless drive) that switches at 20 KHZ or above, 160 volts minimum and 125 amps of peak power. Commutation is either hall-effects or CEMF feedback. Can anyone direct me to a company that offers a drive such as this?

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Pathfinder Tags: Brushless energy efficient motor
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Power-User
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#1

Re: New Motor Technology need a Drive

02/14/2007 1:17 PM

You can look here on GlobalSpec. You'll have to register, but once you do you can put exactly those specs into the search form (the yellow sidebar) and GlobalSpec will find drives that meet your specs from a variety of suppliers. GS doesn't sell the stuff, but can put you in touch with the manufacturer or distributor.

You don't say whether this is a synchronous or asynchronous machine, but since its an ironless machine I'm assuming it's a synchronous PM type machine (the most common type of ironless machine). The first spec you can select on the globalspec search form is which type of motor. The second set of choices lets you specify the drive parameters as shown below:


Good luck!

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Participant

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#2
In reply to #1

Re: New Motor Technology need a Drive

02/14/2007 4:57 PM

Thanks Steve for your direction. I have tried various search engines and with the current requirements of the motor, plus the fact that without the losses, the mechanical time constant approaches the electrical time constant, I have been unable to find an IGBT drive that will switch this fast. The motor will actually follow the switching frequency is it is less than 20 KHZ

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#3
In reply to #2

Re: New Motor Technology need a Drive

02/14/2007 5:11 PM

20 kHz is awfully fast for a conventional hard-switched inverter at that power level. We built some IGBT inverters that switched that fast in my previous life (I ran a power conversion group at GE Corporate Research & Development), but they were soft-switched inverters that we custom-built. Here's a good place for some basic information: http://www.powerdesigners.com/InfoWeb/design_center/articles/SSI/ssi.shtm

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Participant

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#4
In reply to #3

Re: New Motor Technology need a Drive

02/14/2007 8:37 PM

Steve,

I read your article and believe that a soft-switched drive as is described in the article would at least get my motor in the ballpark. I did initially run the drive with an 18 KHZ drive when it was created.

Do you know of any company that manufactures such a drive. It doesn't have to be on-the-shelf, just someone with this capability. (I interfaced many DC 300 and other GE drives in my past CNC engineer life. Also was at Erie a few times)

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#5
In reply to #4

Re: New Motor Technology need a Drive

02/15/2007 11:32 AM

I don't know of any commercial soft-switched drives, but I've been out of the industry for about 10 years now so I'm not a reliable source of information !

Do you need high bandwidth servo performance from this motor? If not, I wonder if you could just add some inductance in the phase legs to slow down the time constants - at some loss of efficiency?

Another option might be to buy an inverter with a much higher rating than you need, that could tolerate the increased switching losses of running at high frequency. That would take some careful analysis of the inverter to make sure it's actually capable of running at such high frequency.

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