| 摘要 |
In an adjustable a.c. power supply for an air-conditioner system, comprising a first frequency converter 9A for driving a compressor motor 6A of a first air-conditioner 7A, a second frequency converter 9B for driving a compressor motor 6B of a second air-conditioner 7B, and a common a.c. power supply 2 for delivering an a.c. power to the both frequency converters, a rectifier 3B included in at least one frequency converter 9B is constructed as a controllable rectifier and the rectifier 3B included in the second frequency converter 9B is subjected to phase-control so that a synthetic higher harmonic current of the two frequency converters when viewed from the a.c. power supply is reduced. By conducting a phase-control of the rectifiers in a manner that, e.g., one rectifier 3A has a phase-control angle of zero degrees and the other rectifier 3B has a phase-control angle of 30 degrees, a load current from the a.c. power supply 2 is permitted to have a waveform closer to a sine wave, i.e., a waveform in which higher harmonic components are further reduced. |
