Patent ID: 8564229

Claim:
A motor controlling device for controlling a brushless motor having a plurality of phases based on magnetic pole signals output by a plurality of magnetic pole signal output sections each corresponding to one of the phases, the device comprising: an abnormality determining section that determines whether a magnetic pole signal output by each magnetic pole signal output section is an abnormal magnetic pole signal; a signal generating section, wherein when the abnormality determining section determines that at least one of the magnetic pole signals is an abnormal magnetic pole signal, the signal generating section generates a simulated signal corresponding to the abnormal magnetic pole signal based on the normal magnetic pole signals other than the abnormal magnetic pole signal and the rotational state of the brushless motor; a motor controlling section that controls the brushless motor based on the simulated signal and the normal magnetic pole signals when the signal generating section generates the simulated signal; and an edge detecting section for detecting rising edges and falling edges of each magnetic pole signal, the brushless motor having three phases, wherein, when the abnormality determining section determines that one of the three magnetic pole signals is an abnormal magnetic pole signal while the rotation of the brushless motor is accelerating, the signal generating section: sets a time point at which a rising edge of the simulated signal occurs such that a rising edge interval is shorter than a first time interval, the first time interval being a period from when a rising edge of a first magnetic pole signal of the normal magnetic pole signals occurs to when a falling edge of a second magnetic pole signal of the normal magnetic pole signal occurs, and the rising edge interval being a period from when a falling edge of the second magnetic pole signal occurs to when a rising edge of the simulated signal occurs, and sets a time point at which a falling edge of the simulated signal occurs such that a falling edge interval is shorter than a second time interval, the second time interval being a period from when a falling edge of the first magnetic pole signal occurs to when a rising edge of the second magnetic pole signal occurs, and the falling edge interval being a period from when a rising edge of the second magnetic pole signal occurs to when a falling edge of the simulated signal occurs.