Provided is a method of assessing rotor temperature during operation of a permanent magnet synchronous machine, including a stator having at least one winding set, the method including: providing reference flux linkage values for different rotor and stator temperature values and current values of an operating winding set; measuring an actual rotor temperature value; measuring an actual stator temperature value; measuring an actual current value of an operating winding set; deriving and storing reference flux linkage values for a given set of operating conditions, in particular, by means of a reference run; deriving a reference flux linkage value (for the measured actual rotor and stator temperature values and the measured actual current value of the operating winding set) using the flux model; obtaining a voltage value; deriving an estimated flux linkage value; deriving a rotor temperature offset; and assessing the rotor temperature based on the rotor temperature offset.

The invention relates to a method and device for operating an electric machine (10) for outputting a predefined torque and a predefined rotational speed, comprising the following steps: providing (420) a first and a second operating mode for the operation of the electric machine (10); detecting (430) a temperature of the electric machine (10); and operating the electric machine (10) in the first operating mode (440) if the detected temperature falls below a threshold value, and operating the electric machine (10) in the second operating mode (450) if the detected temperature corresponds with the threshold value or exceeds same. During the operation of the electric machine (10) in the second operating mode (450), with the resulting output of the predefined torque and the predefined rotational speed, the magnetic stator flux of the electric machine (10) is reduced compared with the magnetic stator flux of the electric machine (10) during the operation of the electric machine (10) in the first operating mode (440), with the resulting output of the predefined torque and the predefined rotational speed.

In the present invention, an electric motor model comprises: a model of a coil of a stator; and a model of a temperature detector for detecting the temperature of the coil. A parameter such as a thermal capacity is included in the electric motor model. Provided is a parameter setting unit comprising a parameter calculation unit that calculates a parameter so that a change in the temperature of the model of the temperature detector corresponds to a change in the actual temperature. The parameter calculation unit includes an evaluation unit that evaluates the temperature of the model of the temperature detector, the temperature having been calculated using the temporarily set parameter. The evaluation unit evaluates the temperature of the model of the temperature detector without evaluating any variables besides the temperature of the model of the temperature detector.

A power conversion device control system includes a power conversion device configured to supply electric power to a rotary electric machine, and a control device configured to control the power conversion device, wherein the control device controls the power conversion device through synchronous control in which a carrier frequency of the power conversion device is proportional to a rotational speed of the rotary electric machine when a temperature of a permanent magnet provided in the rotary electric machine is higher than a predetermined threshold value, and controls the power conversion device through non-synchronous control in which a carrier frequency of the power conversion device is not proportional to a rotational speed of the rotary electric machine when a temperature of the permanent magnet is the predetermined threshold value or less.

A vacuum pump according to an embodiment of the present invention includes a pump main body, a first temperature sensor, a motor, and a control unit. The pump main body includes a rotary shaft and a metal casing portion. The first temperature sensor is attached to the casing portion and detects a temperature of the casing portion. The motor includes a rotor core including a permanent magnet and attached to the rotary shaft, a stator core including a plurality of coils, and a can that houses the rotor core. The control unit includes a driving circuit and a correcting circuit. The driving circuit supplies the plurality of coils with a driving signal for rotating the motor on a basis of a pre-set induced voltage constant. The correcting circuit corrects the induced voltage constant on a basis of an output of the first temperature sensor.

Provided are methods for monitoring temperatures of permanent magnets disposed on rotors of permanent magnet motors. Also provided are vehicle drivetrains including permanent magnet motors and controllers operable to monitor temperatures of permanent magnets used in these motors. A magnet temperature is determined based on the rotational speed of the motor and also based on the open circuit voltage of the motor at this rotational speed. The motor may be specifically calibrated to determine its response to magnet temperature changes for any rotational speed. During operation, an inverter connected to the motor and controlling motor's operation may pause its switching for a period of time and check the open circuit voltage of the motor during this period. The corresponding rotor speed may be obtained from other sensors. The controller uses this information to determine the magnet temperature and, in some embodiments, to perform various control operations to avoid overheating.

A vehicle and method of controlling the same are provided in which the performance of an electric motor is prevented from being degraded by efficiently and more accurately calculating the temperature of a permanent magnet within the electric motor to adjust the amount of power supplied to the electric motor. The vehicle includes an electric motor having a stator, a rotor, and a permanent magnet and a sensor that measures the temperature of the electric motor. An inverter drives the electric motor and a controller generates a predetermined heat quantity by supplying power to the electric motor to calculate the temperature of the permanent magnet based on the temperature of the electric motor at a predetermined point measured using the sensor. When the temperature of the permanent magnet exceeds a predetermined temperature, the controller reduces the supply of the power.

A vehicle and method of controlling the same are provided in which the performance of an electric motor is prevented from being degraded by efficiently and more accurately calculating the temperature of a permanent magnet within the electric motor to adjust the amount of power supplied to the electric motor. The vehicle includes an electric motor having a stator, a rotor, and a permanent magnet and a sensor that measures the temperature of the electric motor. An inverter drives the electric motor and a controller generates a predetermined heat quantity by supplying power to the electric motor to calculate the temperature of the permanent magnet based on the temperature of the electric motor at a predetermined point measured using the sensor. When the temperature of the permanent magnet exceeds a predetermined temperature, the controller reduces the supply of the power.

To provide a three phase duplexing motor for electric power steering apparatus that can manage increase in a supply current and can manage influence on motor, when increasing a supply current to the three phase windings of the normal set. An three phase duplexing motor for electric power steering apparatus sets 0 to a supply current to three phase winding of abnormality occurrence set, and increases a supply current to three phase windings of the normal set, with a preliminarily set increase upper limit current value as an upper limit.

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.