Patent ID: 8736208

Claim:
A motor control device that controls a three-phase brushless motor including a rotor and field coils, comprising: a driving circuit that includes three series circuits each formed by connecting two switching elements in series corresponding to three phases, where the series circuits are connected in parallel between a power supply and a ground, and regenerative diodes are connected in parallel to the respective switching elements; and a controllable region identifying unit configured to identify a rotor rotation angle region in which driving of the three-phase brushless motor is possible as a controllable region when one of the switching elements has short-circuit faulted; wherein when the rotor of the three-phase brushless motor is rotated in a state where all switching elements other than the switching element that has short-circuit faulted are off, in a case where a rotor rotation angle region in which a load current flows in neither of two normal phases is defined as a possible region, a rotor rotation angle region in which a load current flows in either one of the two normal phases is defined as an indeterminate region, and a rotor rotation angle region in which a load current flows in both of the two normal phases is defined as an impossible region, the controllable region identifying unit is arranged to identify a region consisting of the possible region and the indeterminate region or the possible region as the controllable region.