Motor control apparatus

An upper switching device and a lower switching device in an electric-power conversion unit are separately driven to close by an upper closing command signal and a lower closing command signal, respectively, generated by a calculation control unit; in response to occurrence of an excessive current abnormality or an excessive voltage abnormality, upper and lower selection circuits and a penetration prevention circuit provided in a signal path select an upper three-phase short-circuiting command signal or a lower three-phase short-circuiting command signal, or an upper-and-lower six-phase cutoff command signal, and a penetration prevention time prohibits upper and lower switching devices from being concurrently closed; when an excessive voltage abnormality occurs, the three-phase short-circuiting command signal is immediately generated, without an advanced cutoff operation being performed. As a result, excessive-voltage breakage of the circuit components is prevented.