| 摘要 |
PURPOSE:To make use of the capacity of a commutatorless motor at its maximum by a method wherein the change speed of the number of revolutions of a compressor and the number of revolutions of the commutatorless motor is detected and a change in the change amount per unit time of a voltage applied to the commutatorless motor is adjusted in such a way that the change speed of the number of resolutions coincides with a target change speed. CONSTITUTION:When a compressor 3 reaches a definite speed, a rotor-position detection circuit 5 detects the magnet-pole position of a rotor, it sends the position to a microcomputer 6, and the applied voltage of a commutatorless motor (MT) is adjusted by a chopping circuit 7. For example, when the number of revolutions of the MT is increased and reaches a definite speed, the MT is changed over to a closed-loop control operation, and the number of revolutions 51 is detected from the position of the rotor and stored in a memory in the microcomputer 6. After a prescribed time, the number of revolutions 52 is detected again. When the increase degree of the number of revolutions per unit time exceeds a target increase speed, the change rate of an applied voltage is lowered by one step. When it is less than the target increase speed, the change rate of the applied voltage is increased by one step. |
