Method for reconfiguring an electric machine including a rotor arranged to rotate with an angular speed (), the electric machine being arranged to pass from a first configuration (config.sub.1) to a second configuration (config.sub.2), the method comprising the steps of: a) determining in real-time a real speed threshold (.sub.real_th) depending on the current operating condition of the electric machine; b) checking if the angular speed () of the rotor is greater than said real speed threshold (.sub.real_th); c) in positive case, no reconfiguration is performed from the first configuration (config.sub.1); d) in negative case: d.1) determining the current configuration of the electric machine; d.2) selecting a reconfiguring decision method; d.3) deciding whether to reconfigure the electric machine or not and, in positive case, reconfiguring the electric machine.

A control system for generating a modified torque command for a rotating electrical machine in a battery electric vehicle (BEV) includes a microprocessor, capable of reading executable commands stored in non-volatile memory, configured to electrically connect to an inverter, determine a rated maximum current of the rotating electrical machine, receive sensor input indicating a temperature or estimating the temperature of at least one portion of the BEV, output a modified maximum current based on the received sensor input, and generate a torque command to the rotating electrical machine based on the modified maximum current.

An electric machine assembly has an electric machine having a stator and a rotor. The rotor has a rotor temperature and is configured to rotate at a rotor speed (). The stator has stator windings at a stator winding temperature (t.sub.S) and the electric machine defines a number of pole pairs (P). A controller is operatively connected to the electric machine and is configured to receive a torque command (T*). The controller has a processor and tangible, non-transitory memory on which is recorded instructions for executing a method for determining a total permanent magnetic flux (.sub.T) as a function of the rotor temperature. Execution of the instructions by the processor causes the controller to determine a high-speed magnetic flux factor (.sub.H) and a low-speed magnetic flux factor (.sub.L).

The controller for an actuator that is driven by a brushless motor estimates the temperature of the magnet in the brushless motor on the basis of an electric current value and a rotation speed thereof which are obtained by supplying power to rotate the brushless motor in a reverse direction, and limits current flowing through the brushless motor during forward rotation so as to prevent the magnet temperature from rising beyond an allowable maximum temperature. Limiting the current flowing through the brushless motor on the basis of the estimated magnet temperature makes it possible to drive the brushless motor while preventing the magnet temperature from rising beyond the allowable maximum temperature without providing the brushless motor with any temperature sensor for detecting the magnet temperature therein.

Techniques for motor magnet degradation controls and diagnostics are disclosed. An exemplary technique determines q-axis current, d-axis current, q-axis voltage, and/or d-axis voltage of a permanent magnet motor based upon sensed current and voltage information of the motor. This information is utilized to determine flux information. The flux information is utilized in evaluating collective state conditions of a plurality of motor magnets and evaluating localized state conditions of a subset of the plurality of motor magnets. The evaluations can be used to identify degradation or damage to one or more of the magnets which may occur as a result of elevated temperature conditions, physical degradation, or chemical degradation.

Rotor flux control in a permanent magnet (PM) electric machine involves controlling fluid flow through the rotor based on the torque versus speed operating point of the PM machine. When the torque at a given speed falls below a predetermined threshold, the rotor receives a reduced fluid flow compared to when the torque is above the threshold. Fluid flow through the stator is controlled in an inverse manner relative to the rotor's fluid flow such that when the rotor experiences reduced fluid flow, the stator receives an increased fluid flow. This approach enables efficient control of the rotor's magnetic flux, enhancing the performance and efficiency of the PM electric machine during various operating conditions.

A drive system for a brushless DC motor having a rotor includes at least one permanent magnet and a stator including at least one phase winding. The system has a drive circuit including a switch associated with the winding for varying the current passing through the winding; a rotor position sensor arranged to sense the position of the rotor; and a controller arranged to provide drive signals to control the switch. The drive system is further arranged to receive a temperature signal that has a value dependent upon the temperature of the at least one magnet of the rotor. The controller is arranged to vary the phase of the current passing through the winding relative to the rotor position dependent upon the temperature of the rotor magnet.

Techniques for motor magnet degradation controls and diagnostics are disclosed. An exemplary technique determines q-axis current, d-axis current, q-axis voltage, and/or d-axis voltage of a permanent magnet motor based upon sensed current and voltage information of the motor. This information is utilized to determine flux information. The flux information is utilized in evaluating collective state conditions of a plurality of motor magnets and evaluating localized state conditions of a subset of the plurality of motor magnets. The evaluations can be used to identify degradation or damage to one or more of the magnets which may occur as a result of elevated temperature conditions, physical degradation, or chemical degradation.

An electric machine assembly has an electric machine having a stator and a rotor. The rotor has a rotor temperature and is configured to rotate at a rotor speed (). The stator has stator windings at a stator winding temperature (t.sub.S) and the electric machine defines a number of pole pairs (P). A controller is operatively connected to the electric machine and is configured to receive a torque command (T*). The controller has a processor and tangible, non-transitory memory on which is recorded instructions for executing a method for determining a total permanent magnetic flux (.sub.T) as a function of the rotor temperature. Execution of the instructions by the processor causes the controller to determine a high-speed magnetic flux factor (.sub.H) and a low-speed magnetic flux factor (.sub.L).

In order to highly accurately estimate a temperature of a permanent magnet to be used for a rotor of a motor, provided is a motor control device for a vehicle including a motor as a drive power source, in which an estimation mode setting section sets, when a predetermined condition for estimating the temperature of the permanent magnet to be used for the rotor of the motor is established under a state in which the motor generates drive power to run the vehicle, a current flowing through the motor to 0, and a permanent magnet temperature estimation section estimates the temperature of the permanent magnet based on an induced voltage of the motor in a period during which the current flowing through the motor is 0.