| 摘要 |
PURPOSE:To improve the efficiency of a vibration type compressor by driving the compressor by the AC power supply of a frequency that the mean current of a current flowing to the compressor becomes minimum. CONSTITUTION:An averaging circuit 22 averages the current flowing to a vibration type compressor 1 detected by a current detector 20. A minimum current controller 24 gradually varies the oscillation frequency of an oscillator 21 at each predetermined time, and so variably controls the oscillation frequency of the oscillator 21 that the means current obtained from the circuit 22 becomes minimum. The AC voltage of a frequency that the mean current of the current flowing to the compressor 1 becomes minimum is automatically generated, and the compressor 1 is driven by its AC power. Accordingly, the compressor 1 is always driven by the AC power near a maximum efficiency. Thus, the efficiency of the compressor 1 is improved. |
