There is obtained an electric-power conversion apparatus that prevents it that the temperature of a semiconductor switching device reaches a breakage temperature and hence the semiconductor switching device is broken and that realizes continuity of driving. The electric-power conversion apparatus includes a temperature sensor that detects a temperature of semiconductor switching device, and a temperature rising rate determination unit that compares a predetermined first threshold value with a temperature rising rate calculated based on a temperature detection value detected by the temperature sensor and determines that the temperature rising rate has exceeded the first threshold value; when the temperature rising rate determination unit determines that the temperature rising rate has exceeded the first threshold value, protective operation for suppressing an output of an electric-power conversion unit is performed.

a permanent magnet synchronous motor diagnostic device includes: a negative-sequence current calculator that calculates a negative-sequence current, based on magnitudes of a plurality of phase currents flowing through a permanent magnet synchronous motor that rotates a load; and a deterioration diagnoser that diagnoses deterioration of a plain bearing supporting the permanent magnet synchronous motor, based on the negative-sequence current.

An abnormality diagnosis system configured to diagnose an abnormality of an electric drive system mounted on a mobile body to drive a motor for moving the mobile body, includes: an information acquisition unit configured to acquire a motor output information which is information related to an output state of the motor; an output state determination unit configured to determine whether the output state of the motor is in a low output state that does not contribute to a movement of the mobile body by using the motor output information; and a diagnosis execution unit configured to diagnose an abnormality of the electric drive system when it is determined that the motor is in the low output state.

A motor control system includes a main control unit, a power supply unit, and a driving unit. The main control unit obtains sampling data of a motor and a power supply signal from the driving unit, generates a motor control signal according to the sampling data, and outputs a safety enable signal when determining that motor drive is abnormal according to the sampling data or when determining that power supply to the driving unit is abnormal according to the power supply signal. The power supply unit supplies power to the main control unit, monitors a state of the main control unit, and outputs a safety cut-off signal when the power supply unit or the main control unit is abnormal. The driving unit drives the motor according to the motor control signal, and switches to a safe path when receiving any one of the safety enable or safety cut-off signal.

A current detection unit includes current detection elements provided to phases on a high potential side of an upper arm element or on a low potential side of a lower arm element. A detection target element is the upper arm element or the lower arm element to which the current detection elements are provided. A target duty is a duty ratio of the detection target element. The control unit includes a current acquisition unit, an energization control unit, and an abnormality determination unit. The current acquisition unit acquires a current detection value from the current detection unit. The abnormality determination unit performs an abnormality determination based on the current detection value. The abnormality determination unit varies a determination threshold, which is used for the abnormality determination based on the current detection value, according to the target duty.

A current measurement apparatus for a three-phase inverter, according to one embodiment of the present invention, comprises: a current detection element connected to a lower end of one of three lower switches constituting the inverter; a current measurement unit measuring currents by using the current detection element and the two lower switches that are not connected to the current detection element; and a current correction unit for correcting, on the basis of the relationship between a first current value measured by means of the current detection element and second and third current values measured by means of the two lower switches, the second and third current values.

A motor control device includes a motor, a drive circuit, a current detection unit, and a control unit. The motor has a plurality of phases of motor windings. The drive circuit is provided on a low potential side of the motor windings. The current detection unit has current detection resistors corresponding to each phase, and is provided on a low potential side of the drive circuit. The control unit includes an actuator control unit and an abnormality diagnosis unit. The abnormality diagnosis unit determines that the current detection unit is abnormal, when a difference between a maximum current, which is a maximum value of the phase current when a same duty ratio is commanded to each phase, and a minimum current, which is a minimum value of the phase current when a same duty ratio is commanded to each phase, is equal to or greater than an abnormality determination threshold.

A motor control device includes a motor, a drive circuit, a current detection unit, and a control unit. The motor has a plurality of phases of motor windings. The drive circuit is provided on a low potential side of the motor windings. The current detection unit has current detection resistors corresponding to each phase, and is provided on a low potential side of the drive circuit. The control unit includes an actuator control unit and an abnormality diagnosis unit. The abnormality diagnosis unit determines that the current detection unit is abnormal, when a difference between a maximum current, which is a maximum value of the phase current when a same duty ratio is commanded to each phase, and a minimum current, which is a minimum value of the phase current when a same duty ratio is commanded to each phase, is equal to or greater than an abnormality determination threshold.

A method and position sensor system for detecting an error of a position sensor system are provided. The method and position sensor system implementing the steps of: determining the period length of three previous signal periods of the position signal, comparing the period lengths of the three previous signal periods of the position signal to detect a constant velocity position signal, a constant accelerating or decelerating position signal or position signal with a constant jerk, predicting the period length of the next signal period of the position signal, transferring the predicted period length of the next signal period to a predicted position signal for the next signal period, and comparing the predicted position signal with the actual position signal to detect errors in the position signal of the next signal period.

A method and position sensor system for detecting an error of a position sensor system are provided. The method and position sensor system implementing the steps of: determining the period length of three previous signal periods of the position signal, comparing the period lengths of the three previous signal periods of the position signal to detect a constant velocity position signal, a constant accelerating or decelerating position signal or position signal with a constant jerk, predicting the period length of the next signal period of the position signal, transferring the predicted period length of the next signal period to a predicted position signal for the next signal period, and comparing the predicted position signal with the actual position signal to detect errors in the position signal of the next signal period.