| 摘要 |
PURPOSE:To avoid the decline of a motor efficiency caused by the delay of the rise of a winding current from a commutation timing in an inverter which facilitates that, in order to drive a brushless motor with PWM(pulse width modulation) control, the rotor rotating position of the motor is recognized by waveform synthesis from the terminal voltage of the motor winding and a recognition waveform having commutation timing information is formed and the commutation timing of the winding is obtained in accordance with the recognition waveform. CONSTITUTION:A current applied to a three-phase bridge circuit 13 is detected by a shunt resistor 32. A time corresponding to an electrical angle of 30 degrees from the rise time of a recognition waveform is used as a reference timing. The reference timing is corrected so as to have a detected current minimum and the commutation timing of a motor winding is determined. |
