Parameters relating to rotation of a motor (2) measured every constant time are acquired and the moving average of each constant interval of the parameters is calculated. The calculated moving averages are input to a training model trained so as to output a temperature of magnets attached to a rotor (7) of the motor (2) when the moving averages of the parameters relating to rotation of the motor (2) are input, and an estimated value of the magnet temperature output from the model is acquired. Next, the acquired estimated value of the magnet temperature is output.

A controller for a rotary electric machine may include: at least one memory that stores a temperature prediction data in which a relationship among a rotational speed of a rotary electric machine, a torque information of the rotary electric machine, a temperature of the rotary electric machine at a reference time point, and a temperature of the rotary electric machine after an estimation calculation period elapses from the reference time point, and at least one processor that, at every estimation calculation period, sets the last calculation time before the estimation calculation period as the reference time point, and, by referring to the temperature prediction data, calculates an estimation value of temperature of the rotary electric machine after the estimation calculation period elapses from the last calculation time.

A rotating machine control device for controlling a rotating machine having a stator winding and a field winding includes a current command generation unit which generates a current command value on the basis of the temperature of the rotating machine. The current command generation unit includes a constraint condition setting unit which calculates a constraint condition on the basis of a torque command, stator winding voltage, stator winding current, and field winding current, an optimization calculation unit which calculates and outputs the current command value, using the constraint condition and an evaluation function, and a constraint condition update unit which updates the constraint condition on the basis of the temperature of the rotating machine. The current command generation unit calculates and outputs the current command value, using the updated constraint condition.

An arrangement for determining a temperature of an electric machine includes a supply unit for operating the electric machine, with a first temperature of the electric machine computed with a first thermal model of the electric machine in the supply unit, and a computing facility connected to the supply unit by way of a data transmission channel, with a second temperature of the electric machine computed with a second thermal model of the electric machine in the computing facility. The supply unit and the computing facility communicate by way of the data transmission channel so as to enable the computing facility to determine the second temperature of the electric machine with the second thermal model even when no current is supplied to the supply unit.

A rotor temperature monitoring method and system for a permanent magnet synchronous motor are provided. According to the method and system, an a-phase line current and a b-phase line current of a stator of a permanent magnet synchronous motor are obtained as a first line current and a second line current; further, a line voltage between the a-phase and the b-phase of the stator is obtained and a rotating speed of the rotor of the permanent magnet synchronous motor is obtained; and then, the first line current, the second line current, the line voltage, the rotating speed of the rotor, an inductance parameter of the permanent magnet synchronous motor and a temperature characteristic equation of a permanent magnet of the rotor are substituted into a preset rotor permanent magnet temperature expression to calculate and obtain the temperature of the rotor.

A rotor temperature monitoring method and system for a permanent magnet synchronous motor are provided. According to the method and system, an a-phase line current and a b-phase line current of a stator of a permanent magnet synchronous motor are obtained as a first line current and a second line current; further, a line voltage between the a-phase and the b-phase of the stator is obtained and a rotating speed of the rotor of the permanent magnet synchronous motor is obtained; and then, the first line current, the second line current, the line voltage, the rotating speed of the rotor, an inductance parameter of the permanent magnet synchronous motor and a temperature characteristic equation of a permanent magnet of the rotor are substituted into a preset rotor permanent magnet temperature expression to calculate and obtain the temperature of the rotor.

A temperature estimating apparatus for a synchronous motor comprises: a voltage command generating unit for controlling d-phase current by increasing or decreasing d-phase and q-phase voltages; a voltage acquiring unit for d-phase and q-phase voltages when the d-phase current is varied; a rotating speed detecting unit for the synchronous motor; a current detecting unit for the d-phase and q-phase currents; a winding temperature acquiring unit; a winding resistance converting unit for winding resistance from winding temperature; an inductance calculating unit for d-axis inductance based on the variation of the d-phase current and the q-phase voltage and on the rotating speed; a counter electromotive voltage constant calculating unit from the q-phase voltage, the varied d-phase current, the rotating speed, the q-phase current, the winding resistance, and the d-axis inductance; and a magnet temperature estimating unit for estimating magnet temperature based on the counter electromotive voltage constant.

To estimate a magnet magnetic flux or a magnet temperature with higher accuracy during a three-phase short circuit operation, than in a case only a d-axis current is used. A control device includes a phase short circuit unit for short-circuiting three-phase terminals of a permanent-magnet-type synchronous machine having a permanent magnet. During three-phase short circuit operation in which the three-phase terminals are short-circuited by the phase short circuit unit and the permanent-magnet-type synchronous machine is operated, the control device estimates a magnet state of the permanent magnet on the basis of a d-axis current, a q-axis current and a magnetic characteristic.

An inverter control device that controls an inverter unit that converts a DC voltage from a converter unit to an AC voltage and supplies the AC voltage to the DC motor includes a storage unit that stores therein information regarding a synchronization-loss limit; a synchronization-loss limit-current calculation unit that calculates the limitation value on the synchronization-loss limit current on the basis of the magnet temperature of the DC motor, the bus voltage to be applied to the inverter unit, and the information regarding a synchronization-loss limit; and a control unit that compares the primary current to be input to the converter unit with the limitation value and that, when the primary current exceeds the limitation value, outputs an adjustment command to adjust the operating frequency of the DC motor such that the primary current becomes equal to or less than the limitation value.

An inverter control device that controls an inverter unit that converts a DC voltage from a converter unit to an AC voltage and supplies the AC voltage to the DC motor includes a storage unit that stores therein information regarding a synchronization-loss limit; a synchronization-loss limit-current calculation unit that calculates the limitation value on the synchronization-loss limit current on the basis of the magnet temperature of the DC motor, the bus voltage to be applied to the inverter unit, and the information regarding a synchronization-loss limit; and a control unit that compares the primary current to be input to the converter unit with the limitation value and that, when the primary current exceeds the limitation value, outputs an adjustment command to adjust the operating frequency of the DC motor such that the primary current becomes equal to or less than the limitation value.