| 摘要 |
PURPOSE:To ensure high responsivity and stable operation regardless of the magnitude of phase difference, by adjusting commutation cycle through propor tion or integration according to the difference between target zero crossing time and actual zero crossing time, so that zero crossing pulses will be generat ed at the target zero crossing time. CONSTITUTION:An arithmetic unit 26 is fed with zero crossing pulses Zr as an interrupt signal, and determines the next commutation cycle based on the difference between target zero crossing time and actual zero crossing time so that zero crossing pulses Zr will be generated at the target zero crossing time. The arithmetic unit 26 allocates commutation control signals AU-BL according to the state of counter-electromotive force signals ZA-ZC. The determined commutation cycle is fed from the arithmetic unit 26 to a second output register 30. This ensures stable operation with high responsivity even if the difference between actual zero crossing time and target zero crossing time is large, that is, phase difference is large. |
