Patent ID: 9543866
Date: 2017-01-10
CPC Classifications: H02P

Claim:
1. A motor drive controller for controlling a motor having multiple phases, the motor drive controller comprising: a comparison reference voltage generator that generates a predetermined constant voltage as a comparison reference voltage; a counter-electromotive voltage comparator that compares the comparison reference voltage with a counter-electromotive voltage of each phase of the motor; and a rotation state detector that detects a rotation state of the motor based on positive/negative polarities of counter-electromotive voltages of other phases with respect to the comparison reference voltage at the time of an occurrence of a zero cross between the counter-electromotive voltage of any one phase and the comparison reference voltage, wherein the number of the phase of the motor is three, and wherein the rotation state detector detects that the motor is in forward rotation at a predetermined speed or higher in a case where, when a zero cross between the rise of the counter-electromotive voltage of any one phase and the comparison reference voltage occurs, the counter-electromotive voltage of another phase leading the phase is positive with respect to the comparison reference voltage, and the counter-electromotive voltage of another phase retarding the phase is negative with respect to the comparison reference voltage.