| 摘要 |
An improvement in a power drive is disclosed that allows four quadrant operation with reduced harmonics. The power drive has a multiphase, non phase shifted transformer with a single common input connected inductive reactance. Multiple series connected power cells are utilized, each configured for four quadrant operation and having a multiphase input and a single phase output, each controllable to reduce harmonics in both the input source line and the output line. Each power cell includes a three phase input converter, a smoothing filter, and a single phase output converter. A method for operating the power drive includes the steps of selectively controlling switching events at the input and output of each power cell such that switching events in respective power cells are spaced apart in time thereby reducing harmonic components. The method can be implemented using pulse width modulation control based upon interdigitated carrier signals which control the input and output of each power cell.
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