Abstract: Various examples are provided related to machines utilizing heavy rare earth (HRE) free permanent magnets. In one example, a rotor assembly including a rotor core having a plurality of rotor slots and magnets positioned within the plurality of rotor slots. At least a portion of the magnets are free of heavy rare earth (HRE) elements. The magnets can include a combination HRE segments and HRE-free segments or can be free of HRE elements. The rotor assembly can be included in an electric machine such as, e.g., a permanent magnet (PM) machine.

Abstract: Various examples are provided related to direct current circuit breakers and their control methods. In one example, among others, a hybrid direct current circuit breaker (DCCB) includes an ultrafast mechanical switch (UFMS) connected in series with a commutating switch (CS) or auxiliary circuit breaker (ACB); a main breaker (MB) including a series of ? semiconductor switching stages in parallel with the UFMS and CS or ACB; and control circuitry that can turn off individual switching stages in a defined order in response to opening contacts of the UFMS. The switching stages can be turned off based upon a dielectric strength across the contacts as they open. In another example, a method includes opening contacts of an UFMS connected in series with a CS or ACB; and turning off individual switching stages of a series of ? semiconductor switching stages connected across the UFMS and the CS or ACB.

Abstract: Disclosed herein is a modular, scalable, and galvanically isolated power electronics converter topology for medium voltage AC (MVAC) to DC or high voltage AC (HVAC) to DC power conversion. A disclosed modular converter can comprise a low-voltage direct current bus and a centralized controller configured to regulate the low-voltage direct current bus. The modular converter can further comprise a plurality of three-phase blocks connected in series. Individual three-phase blocks of the plurality of three-phase blocks can comprise a plurality of single-phase modules connected in an input-series output-parallel configuration. The modular converter can further comprise a filter connected between a grid input and the plurality of three-phase blocks and a pulse-width modulator configured to generate encoded gate pulses for the individual three-phase blocks of the plurality of three-phase blocks.

Abstract: Various examples are provided related to direct current circuit breakers and their control methods. In one example, among others, a hybrid direct current circuit breaker (DCCB) includes an ultrafast mechanical switch (UFMS) connected in series with a commutating switch (CS) or auxiliary circuit breaker (ACB); a main breaker (MB) including a series of ? semiconductor switching stages in parallel with the UFMS and CS or ACB; and control circuitry that can turn off individual switching stages in a defined order in response to opening contacts of the UFMS. The switching stages can be turned off based upon a dielectric strength across the contacts as they open. In another example, a method includes opening contacts of an UFMS connected in series with a CS or ACB; and turning off individual switching stages of a series of ? semiconductor switching stages connected across the UFMS and the CS or ACB.

Abstract: Various examples are provided related to 3D airgap electric machines and winding embedded liquid cooling. In one example, an electric machine includes a stator assembly with stator windings supported by a stator core and an outer rotor assembly includes a radial plate surrounding the stator assembly and an endplate at a first end of the radial plate adjacent to the first end of the stator core. The stator windings can include a first portion extending along an axial length of the stator core and a second portion at a first end of the stator core that extends radially inward towards a shaft of the electric machine. The radial plate can include magnets distributed about the radial plate. In another example, a stator assembly includes stator windings supported by a stator core with a winding support including cooling channels distributed between the stator windings. The winding support can be nonmagnetic.

Abstract: Various examples related to shifted fractional pitch wye-delta multilayer windings and their use in AC machines. In one example, a winding includes a first wye-delta winding with first wye and delta windings for each phase and a second wye-delta winding with second wye and delta windings for each phase. The first and second wye windings for each phase are connected in series and the first and second delta windings are connected in series, and formed wye and delta windings are connected in a wye-delta configuration thereby providing an electrical phase shift between the two windings. The windings are interdigitated to provide a physical shift between the first and second wye windings and the first and second delta windings. Such windings can be used in, e.g., permanent magnet synchronous machines, synchronous machines, reluctance machines, and induction machines.

Abstract: Various examples related to stator and rotor configurations for the improvement in torque density and/or efficiency in AC machines are presented. In one example, a bar wound stator includes a stator core with winding slots; a first group of bar type conductors in the winding slots adjacent to a proximal end adjacent to a rotor air gap surface of the stator core; and a second group of bar type conductors in the winding slots adjacent to a distal end adjacent to a back-iron section of the stator core. The first group of bar type conductors having a first cross-sectional area and the second group of bar type conductors having a second cross-sectional area greater than the first cross-sectional area. In another example, a motor includes the bar wound stator and a rotor such as, e.g., a permanent magnet rotor. The motor can be utilized in hybrid or battery electric vehicles.

Abstract: Various examples are provided related to machines utilizing heavy rare earth (HRE) free permanent magnets. In one example, a rotor assembly including a rotor core having a plurality of rotor slots and magnets positioned within the plurality of rotor slots. At least a portion of the magnets are free of heavy rare earth (HRE) elements. The magnets can include a combination HRE segments and HRE-free segments or can be free of HRE elements. The rotor assembly can be included in an electric machine such as, e.g., a permanent magnet (PM) machine.

Abstract: A power electronic converter can utilize exemplary double synchronous unified virtual oscillator control (DSUVOC) logic or circuitry to convert direct current to alternating current that is input into a power grid. An exemplary DSUVOC controller of the present disclosure includes a double synchronous space vector oscillator component, a sequence extraction component, a fault detection component, a pre-synchronization component, a virtual impedance component, a terminal voltage compensation component, and/or an active damping component, wherein the double synchronous unified virtual oscillator controller is capable of controlling a grid following or a grid forming power electronic converter enabling synchronization and fault ride-through under both balanced and unbalanced conditions.

Abstract: A power electronic converter can utilize exemplary double synchronous unified virtual oscillator control (DSUVOC) logic or circuitry to convert direct current to alternating current that is input into a power grid. An exemplary DSUVOC controller of the present disclosure includes a double synchronous space vector oscillator component, a sequence extraction component, a fault detection component, a pre-synchronization component, a virtual impedance component, a terminal voltage compensation component, and/or an active damping component, wherein the double synchronous unified virtual oscillator controller is capable of controlling a grid following or a grid forming power electronic converter enabling synchronization and fault ride-through under both balanced and unbalanced conditions.

Abstract: Disclosed herein are methods, systems, and devices for providing power conversion between a direct current (DC) source and an alternating current (AC) power grid. According to one embodiment, a power converter device includes a transformer having a first winding and a second winding. The power converter device further includes zero voltage switch circuitry and zero current switch circuitry. The zero voltage switch circuitry is electrically coupled to the first winding, and configured to be electrically coupled to a DC voltage source via a first port and a second port. The zero current switch circuitry is electrically coupled to the second winding of the transformer and configured to be electrically coupled with an AC power grid.

Abstract: Disclosed herein are systems and methods for progressively switched solid-state direct current circuit breakers (“DCCBs”). According to one embodiment, a progressively switched solid-state DCCB includes a fault-sensing device to sense a fault condition in the current provided to a load is disclosed. A controller is configured to receive fault-sensing information from the fault-sensing device and provide control signals for progressively switching the DCCB based on the fault-sensing information. At least two stages, each include two or more series connected power electronic switches, two or more power electronic switches configured to interrupt control current flow through the power electronic switches responsive to receiving one of the control signals, and a voltage clamping device configured to clamp a voltage across the two or more power electronic switches when current flow through the switches is interrupted.

Abstract: Disclosed herein are methods, systems, and devices for providing power conversion between a direct current (DC) source and an alternating current (AC) power grid. According to one embodiment, a power converter device includes a transformer having a first winding and a second winding. The power converter device further includes zero voltage switch circuitry and zero current switch circuitry. The zero voltage switch circuitry is electrically coupled to the first winding, and configured to be electrically coupled to a DC voltage source via a first port and a second port. The zero current switch circuitry is electrically coupled to the second winding of the transformer and configured to be electrically coupled with an AC power grid.

Abstract: Various examples related to shifted fractional pitch wye-delta multilayer windings and their use in AC machines. In one example, a winding includes a first wye-delta winding with first wye and delta windings for each phase and a second wye-delta winding with second wye and delta windings for each phase. The first and second wye windings for each phase are connected in series and the first and second delta windings are connected in series, and formed wye and delta windings are connected in a wye-delta configuration thereby providing an electrical phase shift between the two windings. The windings are interdigitated to provide a physical shift between the first and second wye windings and the first and second delta windings. Such windings can be used in, e.g., permanent magnet synchronous machines, synchronous machines, reluctance machines, and induction machines.

Abstract: A motor control system is provided. The motor control system includes a motor, a position sensor, a current sensor, and a control module. The motor has a rotor and a stator. The motor generates an output torque based on a phase current applied to the motor. The output torque generated by the motor creates a torque ripple that is within a predefined range. The position sensor monitors the motor to determine a rotor position. The current sensor monitors the motor to determine the phase current. The control module is in communication with the motor, the position sensor, and the current sensor. The control module includes a lookup table that stores values of phase current commands. The control module determines a phase current command from the lookup table based on the rotor position and the phase current.

Abstract: A motor control system is provided. The motor control system includes a motor, a position sensor, a current sensor, and a control module. The motor has a rotor and a stator. The motor generates an output torque based on a phase current applied to the motor. The output torque generated by the motor creates a torque ripple that is within a predefined range. The position sensor monitors the motor to determine a rotor position. The current sensor monitors the motor to determine the phase current. The control module is in communication with the motor, the position sensor, and the current sensor. The control module includes a lookup table that stores values of phase current commands. The control module determines a phase current command from the lookup table based on the rotor position and the phase current.

Abstract: Provided is a method of indirect position estimation in three-phase switched reluctance machines. The method may comprise providing a three-phase switched reluctance machine. A three-phase switched reluctance machine may comprise a rotor and three phases. The method may further comprise producing data about the machine, setting threshold current values for at least a first phase; and sensing rotor position. Sensing rotor position may comprise applying a sensing pulse voltage sufficient to induce a pulse current having some maximum amperage in the first phase, determining the amplitude of the maximum amperage of said pulse current with respect to the thresholds for the first phase, and determining the sector of the rotor based upon the amplitude of the maximum amperage of the pulse current in the first phase.

Abstract: Provided is a method of indirect position estimation in three-phase switched reluctance machines. The method may comprise providing a three-phase switched reluctance machine. A three-phase switched reluctance machine may comprise a rotor and three phases. The method may further comprise producing data about the machine, setting threshold current values for at least a first phase; and sensing rotor position. Sensing rotor position may comprise applying a sensing pulse voltage sufficient to induce a pulse current having some maximum amperage in the first phase, determining the amplitude of the maximum amperage of said pulse current with respect to the thresholds for the first phase, and determining the sector of the rotor based upon the amplitude of the maximum amperage of the pulse current in the first phase.

Abstract: In one method for controlling an electric motor, current turn-on and turn-off rotor-position angles for each motor phase are chosen to substantially maximize the absolute value of average motor torque when the motor is operating in two different quadrants of motor torque and motor speed. The first quadrant has positive motor torque and positive motor speed. The second quadrant has negative torque and positive speed. The third quadrant has negative torque and negative speed. The fourth quadrant has positive torque and negative speed. In another method, the motor is operated in at least one of the first and third quadrants and in at least one of the second and fourth quadrants, wherein the absolute value of motor speed is limited when the motor is operating in the first or third quadrants but not in the second or fourth quadrants. In one example, the motor operates a vehicle brake caliper.

Abstract: Disclosed herein is a method for parameter identification in a switched reluctance electric machine comprising: operating the switched reluctance electric machine in response to a desired command; and measuring an actual operating characteristic of the switched reluctance electric machine. The method also includes: modeling the switched reluctance electric machine to formulate an estimated operating characteristic based on the desired command; comparing the actual operating characteristic and the estimated operating characteristic to formulate an error there between; and determining a parameter estimate for the switched reluctance machine based on the error and a previous parameter estimate.