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Some AC drive traction units do not appear to gear change. Why?

April 26, 2017AC appear drive Gear traction units

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Some AC drive traction units do not appear to gear change. Why?

1 Answer

0

10 Posted

Most new inverter drive systems are based on IGBT (transistors) switching devices. Even high voltage IGBTs can now be switched at higher frequencies without excessive losses. By operating at a higher switching frequency (>1kHz) continuously, the PWM waveform can be asynchronous (not tied to the motor synchronous frequency) without undue additional distortion. This removes the need for a mode changing PWM strategy in order to keep the switching frequency synchronous.