| 摘要 |
PURPOSE:To prevent vibrations and noises by computing acceleration by correcting the detected value of position change obtained with the rotational- position detecting circuit in a compressor motor with time, and making the output of the motor approximately equal to the torque of a changing load based on said acceleration. CONSTITUTION:A commercial power source 3 is rectified 4, and a DC voltage Ed is obtained. An inverter 6 is driven with said DC voltage Ed, and AC voltages VA to VC are generated. Thus a compressor motor 7-1 is rotated. A position detecting signal 10S for a rotor is obtained in a phase detector 10 out of the voltages VA to VC by using a filter circuit. The signal 10S is inputted into a microcomputer 9. The microcomputer 9 has a CPU 9-1, a ROM 9-2, a RAM 9-3 and high speed input/output ports HSI and HSO. The data in the RAM 9-3 are operated in the CPU 9-1 using the program in the ROM 9-2, and a rotating speed is obtained. The result is outputted through a current control part 11 and a base driver 12, and the gates of transistors TR1 to TR6 are controlled. In this way, the output of the motor is made approximately equal to the torque of a changing load, and the vibration and the noises of the compressor are prevented. |
