Electric power conversion equipment.

摘要

A two level inverter with switching elements having a higher switching frequency than GTO thyristors provides a continuous control over substantially the full range of output voltages. The inverter comprises as its pulse modes an asynchronous bipolar modulation mode, a multi-pulse mode of an overmodulation mode, and a one pulse mode. Advantageously, the multi-pulse mode and the one pulse mode are arranged to be changed, to enable a continuous control of the output voltage and reduce tone changes in the magnetic noise. <IMAGE>