Magnetic filter

摘要

A magnetic filter filters substantially all of the harmonic frequency currents from a plural-phase power circuit. The power circuit may have three power lines which conduct three currents in a first current set and three power lines which conduct three currents in a second current set. The second current set is displaced from the first current set by a predetermined phase shift. The current sets have a fundamental frequency and a plurality of harmonic frequencies of the fundamental frequency. The magnetic filter may include two transformers each of which has three windings. A first transformer may receive two currents from the first current set and one current from the second current set. A second transformer may receive one current from the first current set and two currents from the second current set. The magnetic filter may also include a phase-shifting coupling transformer having six input phases for receiving the six currents. The transformer may also have three output phases which conduct an output current set. The power circuit may include three power lines for the first current set and three power lines for the second current set. Alternatively, the power circuit may include a first inverter having three power lines for conducting three currents in the first current set and a second inverter having three power lines for conducting three currents in the second current set.