Examples include a method for detecting the evolution of the magnetic state of a permanent magnet rotor. The method includes, during a first and a second time interval, applying a respective direct current command signal to the motor to estimate a respective stator resistance value, and applying a respective alternative voltage command signal corresponding to a specific direct axis stator current value to the motor while measuring respective stator phase current values. The method also includes determining respective rotor flux parameters as a function of the measured respective stator phase current values and of the estimated respective stator resistance values. The method further includes comparing the respective rotor flux parameters. The first and second time intervals are separated by a time period which exceeds at least 100 times any one of a first or second interval length.

An electric motor for viscous pumping, wherein the electric motor is a brushless DC motor configured to be driven by a low DC voltage of around 40-60 VDC, and includes: a rotor with permanent magnets; a stator with a stack of laminations and windings wound therearound; and a controller to provide electronic commutation of electric current flowing through the windings; wherein the windings and the stack of laminations are configured to handle at least 1 kW of continuous electric power from the controller, and the controller includes a feedback circuit including a rotation sensor coupled to the rotor and having an angular resolution of at least 1/500th of a revolution to allow the controller to control the torque generated by the electric motor to a corresponding extent.

An electric motor control device includes an inverter circuit, which has a power conversion circuit configured of six switching elements, and a switching control circuit that controls the switching elements in such a way as to be turned on or off, wherein, when it is determined that the inverter circuit is in an abnormal state, an execution of a three-phase short-circuiting process, whereby all upper side switching elements or all lower side switching elements are turned on, or a six-switch opening process, whereby all the switching elements are turned off, is selected based on a temperature of at least one permanent magnet of an electric motor, in accordance with an operating state of the electric motor.

A control apparatus includes: a rotor temperature estimation unit estimating a temperature of a rotor based on stator temperature information from a first temperature sensor for identifying a temperature of a stator, refrigerant temperature information from a second temperature sensor for identifying a temperature of refrigerant used to cool an electric motor, and rotation speed information about the rotor from a resolver for identifying a rotation speed of the rotor; and an electric motor control unit controlling at least one of an output characteristic and a drive condition of the electric motor based on the temperature of the rotor estimated by the rotor temperature estimation unit.

An iron loss reduction control apparatus for motor permanent magnet overtemperature protection is provided. The apparatus includes: a permanent magnet temperature prediction unit configured to predict a temperature of a permanent magnet in a motor based on a driving state of the motor; a first iron loss reduction unit configured to adjust a switching frequency of a switching element in an inverter providing a driving power to the motor based on the temperature of the permanent magnet; and a second iron loss reduction unit configured to adjust a current command of the motor based on the temperature of the permanent magnet.

The present invention relates to a conveyor system comprising: a drive machine, a conveyor control unit configured to control operation of a conveyor device, a sensor array comprising at least one sensor mounted to the drive machine and adapted to measure one or more properties of the drive machine, a processing unit associated with the drive machine, wherein the processing unit is connected to the sensor array and configured to obtain and process measurement data from the sensor array to generate in-formation about an operation of the drive machine, and a communication channel between the conveyor control unit and the processing unit. The conveyor system may be an elevator system, an escalator system or a moving walk system.

A method for estimating a magnet temperature of a rotor magnet within a rotary electric machine includes, while a rotor of the electric machine is stationary, injecting a high-frequency voltage component onto a control voltage of the electric machine, via a controller, to generate an adjusted voltage command, and extracting a high-frequency component of a resulting current as an extracted high-frequency component. The method also includes calculating an inductance value of the electric machine using the extracted high-frequency component of the resulting current. The magnet temperature is estimated using the calculated inductance value and an angular position of the rotor. The method includes controlling an operation of the electric machine using the estimated magnet temperature. An electric powertrain uses the electric machine and controller noted above.

A driving apparatus includes: an inverter unit generating a three-phase alternating-current voltage from a direct-current voltage in accordance with a drive signal based on a voltage command and outputting the three-phase alternating-current voltage to a permanent-magnet motor, the permanent-magnet motor including a permanent magnet; a current detection unit detecting a motor current flowing through the permanent-magnet motor; and a control unit generating the voltage command to control an operation of the inverter unit and estimating a temperature of the permanent magnet to perform a protection operation on the inverter unit on the basis of the motor current and an overcurrent protection threshold. The control unit sets the overcurrent protection threshold on the basis of a magnet temperature estimated value of the permanent magnet and any one of a control computation period of the control unit, an output voltage frequency of the inverter unit, and a carrier frequency based on the output voltage frequency of the inverter unit.

To provide a controller for rotary electric machine which can estimate a transitional temperature with good accuracy, while considering the heating amount and the heat radiation amount due to copper loss and iron loss which change according to the operating point of rotational speed and torque, and suppressing the increase in arithmetic load. A controller for rotary electric machine, at calculation timing of every estimation calculation period, by referring to a temperature prediction data in which a relationship among a rotational speed, a torque information, a temperature at a reference time point, and a temperature after lapse of the estimation calculation period from the reference time point, calculates an estimation value of temperature after lapse of the estimation calculation period from the last time calculation timing, corresponding to the present rotational speed, the present torque information, and the estimation value of temperature calculated at the last time calculation timing.

A wiper device is provided. A boost control unit, if a duty ratio has reached an upper limit value determined in advance, and if the rotational speed of a motor is less than a target rotational speed, varies an advance angle and an energization angle associated with the energization of the motor in accordance with the target rotational speed. An overtemperature protection unit monitors a load state of the motor, and, upon detecting a high-load state, performs a first protection control for decreasing the rotational speed of the motor. A demagnetization protection unit, upon receipt of an operating signal from a wiper switch when the temperature detected by means of a temperature sensor exceeds a first threshold and the first protection control is being performed, performs a second protection control for fixing the advance angle and energization angle of the motor by prohibiting the operation of the boost control unit.