| 摘要 |
PROBLEM TO BE SOLVED: To prevent reduction of efficiency of a linear compressor following any load variation by detecting a phase difference of the output voltage of an AC power supply from the phase of an electric current following from the AC power supply to a linear motor and correcting the frequency of the output voltage of the AC power supply by a value corresponding to this detected value so as to hold the frequency to the resonant frequency of a piston. SOLUTION: When power is supplied from AC electric power supply 1 to drive a linear compressor 30, the output voltage V of the power supply 1 and the electric current 1 are detected by a voltage detector 2 and an electric current detector 3 respectively. In a phase detecting part 5, erecting timings, etc., of waveforms of a voltage value V and an electric current value I are calculated and depending upon those results, a phase difference of the electric current 1 to the electric voltage V is calculated. Next, a frequency correction amount and a frequency control amount corresponding to the phase difference are counted out by a calculation/control part 6 and frequency control signals corresponding to those amounts are outputted to the power supply 1. Thus, even if the resonant frequency of the piston is varied owing to load variation, the frequency of the output voltage is so controlled as to be always equal to the resonant frequency. |
