DRIVE UNIT FOR MOTOR-DRIVEN COMPRESSOR

摘要

PROBLEM TO BE SOLVED: To obtain a drive unit by which a motor-driven compressor is stabilized with reference to a large change in a power-supply voltage by a method wherein a pulse-width control means is provided with a pulse-width compensation and delay means by which a pulse width is corrected stepwise in every correction time so as to become a prescribed value according to a voltage range detected on the basis of a detection signal. SOLUTION: A voltage-zone detection part 16 detects the voltage of a bettery 11 in every prescribed voltage zone, and a detection result which specifies in which zone the voltage of the battery 11 is situated is output to a pulse-width control part 18. Then, a pulse-width correction and delay part 19 is instaled at the pulse-width control part 18, and the pulse width of the pulse of a pseudo AC voltage is corrected stepwise in every prescribed voltage by the pulse-width correction and delay part 19 so as to be output to a DC-AC conversion circuit 13 in such a way that it becomes a prescribed pulse width according to a voltage zone on the basis of the detection result of the voltage detection part 16. A voltage which is applied to a motor-driven compressor 21 is corrected by the DC-AC conversion circuit 13.