Energy efficient motor drives

Devices created by International Rectifier could be found at APEC under the Infineon Technologies moniker because Infineon acquired IR not long ago. One of the demos featured IR motion control chips powering an A/C unit made in China. The PFC and compressor inverter, fan inverter, and speed controller for both fan and compressor motors used Infineon/IR chips. The speed controller used a sensorless scheme — sensorless control uses the fact that motor windings aren’t all electrically identical, so a sufficiently intelligent controller can track the position of individual windings. But one component you would find in the A/C control was a GaN FET. An Infineon engineer explained that, at least so far, motor controllers typically can’t take advantage of these devices because the high dV/dt that GaN devices make possible (about 5 kV/& #956;sec) generally exceed the insulation capabilities of most motor windings.

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