Techniques and apparatus for determining the temperature of a permanent magnet on a rotor of an electrical motor. An example techniques involves determining a first set of parameters for controlling the electrical motor. A temperature of the rotor during a runtime of the electrical motor is determined, based at least in part on the first set of parameters and a first back-electromotive force (back-emf) associated with the electrical motor. A first estimate of a magnetic flux of the permanent magnet is determined based on the temperature of the rotor. An operation of the electrical motor is controlled based at least in part on the first estimate of the magnetic flux of the permanent magnet.

Electric motors and methods of controlling electric motors are described herein. The electric motors include a mobile component having at least one permanent magnet coupled thereto and a stator spaced apart from the mobile component. The stator includes at least one stator pole having a ferromagnetic core and a coil wrapped around the ferromagnetic core. The ferromagnetic core is naturally attracted to the at least one permanent magnet. The motors also include a magnetic position control system configured to monitor a position of the at least one permanent magnet relative to the stator and controllably deliver an electric pulse to the coil of each stator pole to generate a repulsive magnetic flux on the ferromagnetic core to cancel an attraction force between the ferromagnetic core and the at least one permanent magnet to control movement of the mobile component.

Described examples include a method that includes setting a reference i.sub.q signal in a field-oriented control of a motor such that the field-oriented control modulates power from a power supply using a modulator to apply a torque on the motor that is opposite to a kinetic energy applied to the motor. The method also includes setting a reference i.sub.d signal in the field-oriented control such that the motor current provided to the power supply is reduced.

Described examples include a method that includes setting a reference i.sub.q signal in a field-oriented control of a motor such that the field-oriented control modulates power from a power supply using a modulator to apply a torque on the motor that is opposite to a kinetic energy applied to the motor. The method also includes setting a reference i.sub.d signal in the field-oriented control such that the motor current provided to the power supply is reduced.

Complicated system fault diagnosis method and system based on a multi-stage model are provided. The method includes: establishing an integer-order mathematical model, a 0.1-level fractional order mathematical model, and a 0.01-level fractional order mathematical model of a permanent magnet synchronous motor system; designing an integer-order status observer based on the integer-order mathematical model, designing a 0.1-level fractional order status observer based on the 0.1-level fractional order mathematical model, and designing a 0.01-level fractional order status observer based on the 0.01-level fractional mathematical model; corresponding residual values can be obtained by the observers and compared with corresponding threshold values to judge whether there is a fault. The system includes first through third modules. Observers with different accuracy degrees are set up and the permanent magnet synchronous motor system is diagnosed through the observers. The fault diagnosis method and system are mainly used in motor diagnosis.

According to some embodiments, a method for controlling a motor comprises generating a stall threshold based on a torque generating current parameter associated with the motor. A motor stall condition is identified based on a torque generating voltage parameter associated with the motor violating the stall threshold. Operation of the motor is adjusted responsive to identifying the motor stall condition.

A method for magnetizing a soft magnet in a rotor of a variable-flux memory motor (VFMM) includes: generating a first pulse of electric current that has a duration of equal to or more than 0.1 millisecond (ms) and equal to or less than 2 ms; and applying the first pulse to a stator winding of the VFMM to set a magnetization state of the soft magnet to a first magnetization state.

A motor device 100 includes an SPM motor 1 that includes a stator 2 including an iron core 21 and a plurality of windings 23 wound on the iron core 21, and a rotor 3 which is rotatable with respect to a rotation axis and in which a plurality of permanent magnets 33 are mounted along a circumferential direction to form a plurality of magnetic poles in the circumferential direction; and a power supply unit 5 that supplies a current to the plurality of windings 23 of the SPM motor 1. Each of the plurality of magnetic poles is oriented such that directions of axes of easy magnetization are concentrated toward a stator side, and the current supplied from the power supply unit is a trapezoidal wave.

The technologies described and recited herein pertain to a permanent magnet motor having multiple voltage taps so that the motor may run in multiple configurations, e.g., a low-range and a high-range, and have multiple optimal operating points.

Systems, methods, and apparatus for secondary windings to modify a permanent magnet (PM) field of a permanent magnet synchronous generator (PMSG) are disclosed. In one or more embodiments, a disclosed system for a PMSG comprises a permanent magnet (PM) of the PMSG to rotate and to generate a permanent magnet field. The system further comprises a plurality of stator primary windings (SPW), of the PMSG, to generate primary currents from the permanent magnet field. Further, the system comprises a plurality of stator secondary windings (SSW), of the PMSG, to draw secondary currents from a power source, and to generate a stator secondary winding magnetic field from the secondary currents. In one or more embodiments, the permanent magnet field and the stator secondary winding magnetic field together create an overall magnetic field for the PMSG.