| 摘要 |
A method of determining the position of a rotor of a permanent-magnet motor. The method includes sequentially exciting and freewheeling a winding of the motor. The winding is freewheeled for a freewheel period in response to current in the winding exceeding a current limit. The method also includes measuring a parameter that corresponds to either the magnitude of current in the winding at the end of the freewheel period or the interval between the start or end of the freewheel period and the time at which current in the winding exceeds the current limit. The measured parameter is then compared against a threshold and the rotor is determined to be at a predetermined position when the measured parameter is less than or greater than the threshold. |
