MOTOR CONTROL DEVICE AND ELECTRIC POWER-STEERING DEVICE AND VEHICLE USING SAID MOTOR CONTROL DEVICE

摘要

This invention makes it such that even if a malfunction occurs in a motor drive circuit, drive control of a polyphase electric motor can be continued without an electromagnetic brake acting on said electric motor. This invention includes a main motor drive circuit that performs drive control for the aforementioned polyphase electric motor, a backup motor drive circuit that performs drive control for said polyphase electric motor if a malfunction occurs in the main motor drive circuit, and a malfunction diagnosis unit that diagnoses malfunctions in the main motor drive circuit and the backup motor drive circuit. This invention has a normal drive state in which the polyphase electric motor is driven by the main motor drive circuit alone and a backup drive state in which, if the result of a diagnosis performed on the main motor drive circuit by the malfunction diagnosis unit indicates a malfunction in said main motor drive circuit when in the aforementioned normal drive state, motor current from the malfunctioning phase output unit is interrupted and the polyphase electric motor is driven by switching from the interrupted phase output unit to the phase output unit for the same phase in the backup motor drive circuit.