Motor control device

A motor control device that controls energization of an electric motor, comprising:

• a board that radiates heat generated during energization to a heat sink;
• a plurality of switching elements that are mounted on the board and provide a power converter which supplies an electric power to the electric motor;
• a drive circuit IC that is mounted on the board and includes a pre-driver which outputs a drive signal to the plurality of switching elements;
• a control circuit IC that is mounted on the board and includes a current control unit which calculates a command signal to the pre-driver based on an output command to the electric motor;
• a first temperature sensor and a second temperature sensor that detect temperature at one or two places in at least one of the heat sink, the board, the control circuit IC, the drive circuit IC, the switching element and the electric motor;
• a temperature information processing unit that performs a predetermined process using temperature information on at least one of a first detected temperature detected by the first temperature sensor and a second detected temperature detected by the second temperature sensor;
• and
• an abnormality determination unit that determines an abnormal state of the first and second temperature sensors based on a first detected temperature equivalent amount of the first temperature sensor and a second detected temperature equivalent amount of the second temperature sensor, wherein:
• the first detected temperature equivalent amount is defined by an output value of the first temperature sensor or the first detected temperature calculated by converting the output value of the first temperature sensor;
• the second detected temperature equivalent amount is defined by an output value of the second temperature sensor or the second detected temperature calculated by converting the output value of the second temperature sensor;
• a temperature deviation is defined as an absolute value of a difference between the first detected temperature equivalent amount and the second detected temperature equivalent amount;
• an out-of-normal-range state is defined by a state where the temperature deviation exceeds a normal deviation threshold, and it is impossible to determine which one of the first and second temperature sensors is abnormal;
• when the abnormality determination unit determines that both of the first temperature sensor and the second temperature sensor are normal, the temperature information processing unit uses at least one of the first detected temperature and the second detected temperature;
• when the abnormality determination unit determines that one of the first temperature sensor and the second temperature sensor is abnormal and the other of the first and second temperature sensors is normal, the temperature information processing unit uses one of the first detected temperature and the second detected temperature which is obtained from the one of the first temperature sensor and the second temperature sensor as a normal temperature sensor;
• and
• when the abnormality determination unit determines that both of the first temperature sensor and the second temperature sensor fall in the out-of-normal-range state, the temperature information processing unit uses one of the first detected temperature and the second detected temperature which meets a predetermined condition.