An electric machine includes a stator having a stator winding disposed thereon. A rotor is electromagnetically exposed to the stator. A field winding and an induction winding are disposed on the rotor. A rectifier is electrically coupled to the induction winding and the field winding. Upon application of a voltage to the stator winding, the stator winding produces a first rotating magnetic field and a second rotating magnetic field that has a different spatial frequency than the first rotating magnetic field. The first rotating magnetic field interacts asynchronously with the induction winding to produce an alternating current in the induction winding. The rectifier changes the alternating current to a direct current that is supplied to the field winding. The field winding interacts synchronously with the second rotating magnetic field.

An electric machine includes a stator having a stator winding disposed thereon. A rotor is electromagnetically exposed to the stator. A field winding and an induction winding are disposed on the rotor. A rectifier is electrically coupled to the induction winding and the field winding. Upon application of a voltage to the stator winding, the stator winding produces a first rotating magnetic field and a second rotating magnetic field that has a different spatial frequency than the first rotating magnetic field. The first rotating magnetic field interacts asynchronously with the induction winding to produce an alternating current in the induction winding. The rectifier changes the alternating current to a direct current that is supplied to the field winding. The field winding interacts synchronously with the second rotating magnetic field.

A method includes adjusting currents of a plurality of windings of a motor through a plurality of power converters coupled to the plurality of windings so that the number of poles and the number of phases of the motor are dynamically adjustable, and injecting a plurality of high-order harmonic currents into the plurality of windings of the motor through controlling the plurality of power converters to improve a performance index of the motor.

A method includes adjusting currents of a plurality of windings of a motor through a plurality of power converters coupled to the plurality of windings so that the number of poles and the number of phases of the motor are dynamically adjustable, and injecting a plurality of high-order harmonic currents into the plurality of windings of the motor through controlling the plurality of power converters to improve a performance index of the motor.

A pole-number-changing rotary electric machine includes: a rotary electric machine; an n-group inverter; and a control unit for controlling the n-group inverter, wherein the control unit controls current phases of a current flowing through stator coils such that a current phase degree of freedom, which is a number of current phases per pole pair controllable by the n-group inverter, is equal to a number of groups n×a number of phases m/2 at a time of high polarity driving and the number of groups n×the number of phases m at a time of low polarity driving, where the number of groups n is a multiple of 4 and the number of phases m is a natural number of 3 or more and relatively prime to the number of groups n.

A pole-number-changing rotary electric machine includes: a rotary electric machine; an n-group inverter; and a control unit for controlling the n-group inverter, wherein the control unit controls current phases of a current flowing through stator coils such that a current phase degree of freedom, which is a number of current phases per pole pair controllable by the n-group inverter, is equal to a number of groups n×a number of phases m/2 at a time of high polarity driving and the number of groups n×the number of phases m at a time of low polarity driving, where the number of groups n is a multiple of 4 and the number of phases m is a natural number of 3 or more and relatively prime to the number of groups n.

An electrical induction motor may include a stator with a plurality of circumferentially spaced slots, and N windings installed in the slots and each configured to be connected between two current inputs from an inverter, with a phase angle difference between the two current inputs equal to H×180°/N, wherein H=a harmonic of a current drive waveform supplied by the inverter to the windings. Each of the N windings may be installed in the plurality of slots to form a top layer of winding and a bottom layer of winding, with a phase angle of the current flowing through the top layer of winding in each slot being aligned with a phase angle of current flowing through the bottom layer of winding at a first, higher harmonic, and out of alignment at a second, lower harmonic.

An electrical induction motor may include a stator with a plurality of circumferentially spaced slots, and N windings installed in the slots and each configured to be connected between two current inputs from an inverter, with a phase angle difference between the two current inputs equal to H×180°/N, wherein H=a harmonic of a current drive waveform supplied by the inverter to the windings. Each of the N windings may be installed in the plurality of slots to form a top layer of winding and a bottom layer of winding, with a phase angle of the current flowing through the top layer of winding in each slot being aligned with a phase angle of current flowing through the bottom layer of winding at a first, higher harmonic, and out of alignment at a second, lower harmonic.

Disclosed is a drive train including a drive shaft, a drive machine, and a planetary gearbox having three drives and three outputs, wherein one output is connected to the drive shaft, one drive is connected to the drive machine, and a second drive is connected to an electric differential drive. The differential drive can be connected directly to a network without a frequency converter, in order that the operation of the drive train is possible without a frequency converter.

A method and system of performing a pole switching operation in a multi-phase machine include operating the multi-phase machine in a first configuration with a first number of poles, where the first number of poles is based on a first number of phases in the first configuration and a number of stator slots allocated for each winding in the multi-phase machine. The method and system also include receiving a signal indicating the pole switching operation in the multi-phase machine. In response to receiving the signal, the method and system include operating the multi-phase machine in a second configuration with a second number of poles, where the second number of poles is based on a second number of phases in the second configuration and the number of stator slots allocated for each winding in the multi-phase machine.