| 摘要 |
PURPOSE:To operate a synchronous motor with high effect even in the case the number of revolutions and a load change are large by leading and lagging the output signal of a phase detector to meet the rotating speed and the load change of the motor. CONSTITUTION:The 180 degrees time measuring counter 501 of a phase angle control circuit 5 counts the block pulses of a reference clock circuit 504 from the rise to the fall of the signal of a phase detector 4. Its counted value becomes the input data of a lag angle and lead angle deciding circuit 52, which calculates the number of the revolutions of a synchronous motor from the counted value. The circuit 52 also inputs voltage and current signals of a power source. The circuit 52 has a lag angle and lead angle map to be decided according to the number of the revolutions, the voltage and the current, and decides the lag angle and the lead angle according to the number of the revolutions, the voltage and the current. Thus, the motor can be operated with a high efficiency even when the number of the revolutions, the voltage and the current are large. |
