Abstract: An internal permanent magnet machine (“IPM machine”) of the type used, for example, with traction motors and hybrid electric vehicles, includes a rotor with an additional air barrier provided above the first magnet barrier in the same rotor slot. Each magnet only fills a portion of each cavity, thereby defining the air barriers. The added air barrier above the permanent magnet of the first layer acts as a barrier to the first layer magnet and lowers the magnet flux.

Abstract: Methods and apparatus are provided for improving operational characteristics of a concentrated winding machine. According to an example embodiment, an apparatus comprises stator teeth having distal ends, the stator teeth arranged in an annular fashion about an axis to define stator slots between adjacent teeth and slot openings between the distal ends of the adjacent teeth, the stator teeth structured to prevent relative movement between adjacent teeth. The apparatus further comprises magnetic wedges structured to be inserted between the distal ends of the adjacent teeth to close the slot openings.

Abstract: A bar-wound stator includes a plurality of bar-type conductors disposed within the plurality of slots, wherein, within each slot, at least one of the bar-type conductors has an orientation that differs from the remaining bar-type conductors within that slot by a predetermined angle. For example, conductors with rectangular cross-sections can be inserted such that the conductors closest to the inner surface of the stator are rotated ninety degrees with respect to the remaining conductors.

Abstract: Systems and methods are provided for identifying a fault condition in stator windings in an electric motor. A method comprises applying a first signal at a first electrical angle to the stator windings and measuring a second signal from the stator windings in response to the first signal. The method further comprises determining a measured response for the electric motor at the first electrical angle based on the second signal and obtaining a nominal response for the electric motor at the first electrical angle. A fault condition is identified when a magnitude of the difference between the measured response and the nominal response is greater than a threshold value.

Abstract: A method of detecting a phase winding fault in a multi-phase electric machine is executable via a motor controller, and includes measuring feedback signals of the machine, including each phase current, and generating reference phase voltages for each phase. The method includes calculating a predetermined voltage value using the feedback signals and reference phase voltages, and comparing the voltage value to a corresponding threshold to determine the fault. A control action is executed when the voltage value exceeds the corresponding threshold. The voltage value is one or more of: a ratio of a normalized negative sequence voltage to a modulation index, an RMS voltage for each phase, and total harmonic distortion of each phase current. An apparatus detects the fault, and includes a motor controller and an algorithm as set forth above. The apparatus may include a voltage inverter for generating a multi-phase alternating current output for powering the machine.

Abstract: An electric motor includes a rotor and a stator assembly concentrically located about the rotor. The stator assembly includes a stator stack and a plurality of spaced apart stator teeth extending radially from the stator stack. The plurality of stator teeth defines a plurality of stator slots. Each stator tooth defines a stator tooth tip.

Abstract: Permanent magnet motors with improved torque ripple and methods for designing the same have been provided. The permanent magnet motor can include a stator having a hollow core and defining a plurality of slots; a winding disposed in each of the slots; a rotor rotatably disposed inside the hollow core of the stator; and a plurality of permanent magnets supported by the rotor. Each of the slots has a slot opening, and at least one of the slot openings can be off-center with respect to the respective slot.

Abstract: Methods and apparatus are provided for reducing torque ripple in a permanent magnet motor system comprising a permanent magnet motor coupled to an inverter. The method comprises the steps of receiving a torque command, generating a torque ripple reduction signal in response to the torque command, modifying operational control signals in response to the torque ripple reduction signal to generate reduced ripple operational control signals, and providing the reduced ripple operational control signals to the inverter for control of the permanent magnet motor.

Abstract: A method of detecting a phase winding fault in a multi-phase electric machine is executable via a motor controller, and includes measuring feedback signals of the machine, including each phase current, and generating reference phase voltages for each phase. The method includes calculating a predetermined voltage value using the feedback signals and reference phase voltages, and comparing the voltage value to a corresponding threshold to determine the fault. A control action is executed when the voltage value exceeds the corresponding threshold. The voltage value is one or more of: a ratio of a normalized zero sequence voltage to a modulation index, an RMS voltage for each phase, and total harmonic distortion of each phase current. An apparatus detects the fault, and includes a motor controller and an algorithm as set forth above. The apparatus may include a voltage inverter for generating a multi-phase alternating current output for powering the machine.

Abstract: An assembly for providing electrical insulation in a stator core of a vehicular electric machine is provided. The stator core has a channel and the assembly comprises a first conductive element disposed through the channel, and a second conductive element disposed through the channel and substantially adjacent to the first conductive element. The assembly also comprises a first electrically insulating film having a first end residing between the first and second conductive elements.

Abstract: Systems and methods are provided for a motor having a concentrated winding construction with reduced torque ripple. A motor comprises a stator including a plurality of tooth segments disposed circumferentially to establish a hollow core and a rotor rotatably disposed inside the hollow core. The plurality of tooth segments define a plurality of slot openings associated with a plurality of slots. Each slot of the plurality of slots has a slot opening and at least one slot opening of the plurality of slot openings is asymmetric with respect to the plurality of slot openings.

Abstract: A bar-wound stator includes a plurality of bar-type conductors disposed within the plurality of slots, wherein, within each slot, at least one of the bar-type conductors has an orientation that differs from the remaining bar-type conductors within that slot by a predetermined angle. For example, conductors with rectangular cross-sections can be inserted such that the conductors closest to the inner surface of the stator are rotated ninety degrees with respect to the remaining conductors.

Abstract: Methods and systems for evaluating a permanent magnet motor are provided. The method includes the steps of spinning a rotor of the permanent magnet motor; determining a total harmonic distortion of the permanent magnet motor; and comparing the determined total harmonic distortion of the permanent magnet motor with a baseline total harmonic distortion.

Abstract: A permanent magnet machine includes a stator having a hollow core, a rotor rotatably disposed inside the hollow core, and a plurality of multilayered permanent magnets embedded in the rotor. Each multilayered permanent magnet has opposite first and second ends, and includes a first magnet disposed at the first end, and a second magnet disposed at the second end and coupled to the first magnet. The second magnet has higher magnet strength than the first magnet, and also has lower high-temperature stability than the first magnet.

Abstract: Systems and methods are provided for identifying a fault condition in stator windings in an electric motor. A method comprises applying a first signal at a first electrical angle to the stator windings and measuring a second signal from the stator windings in response to the first signal. The method further comprises determining a measured response for the electric motor at the first electrical angle based on the second signal and obtaining a nominal response for the electric motor at the first electrical angle. A fault condition is identified when a magnitude of the difference between the measured response and the nominal response is greater than a threshold value.

Abstract: A rotor for an electric machine includes a plurality of magnet stacks having at least five permanent magnets formed into a skew pattern within each of the magnet stacks. The skew pattern has a skew angle and at least two skew steps, and is an angle of rotation about the axis between individual magnets adjacent to the skew steps. The skew pattern may be an axially-symmetric V-shape. The plurality of magnet stacks may have five, six, or eight permanent magnets therein. The number of skew steps may be equal to two or three. The skew angle may be calculated as 360 degrees, divided by the number of skew steps plus one, multiplied by the least common multiple of the number of rotor poles and the number of the plurality of stator slots.

Abstract: In general, the various embodiments are directed to a permanent magnet machine (“PM machine”), and more specifically an internal permanent magnet machine (“IPM machine”) that includes rotor magnets configured asymmetrically with respect to the rotor periphery, thereby producing an averaging effect similar to that achieved through traditional skewing of the rotor magnets. In alternate embodiments, the span, placement and/or shape of the magnets may vary from one pole to the next.

Abstract: A powertrain is provided that includes an engine as well as a transmission having an input member and an output member. The powertrain also includes a motor/generator that has an energizable stator, a first rotor and a second rotor (i.e., a dual rotor motor). Both of the rotors are rotatable via energization of the stator. A first torque-transmitting mechanism, referred to as the engine clutch, is selectively engagable to connect the engine for common rotation with one of the first and the second rotors. A second torque-transmitting mechanism, referred to as the motor clutch, is selectively engagable to connect the first rotor for common rotation with the second rotor. The transmission input member is continuously connected for common rotation with the other of the first and second rotors.

Abstract: Methods are provided for forming/inserting a magnet in a rotor. One method includes coating a plurality of magnetizable particles with a non-metallic material, inserting the coated particles in a rotor, and magnetizing the coated particles. Another method includes inserting a plurality of magnetizable particles into a rotor, submersing the rotor in motor varnish or another viscous, non-metallic material to coat the particles, and magnetizing the particles. Yet another method includes inserting a plurality of magnetizable particles in a rotor, inserting a non-metallic material into the rotor, mixing the particles and non-metallic material to form a mixture, curing the mixture to coat each particle with non-metallic material, and magnetizing the particles.

Abstract: An apparatus includes a multi-phase inverter, a fault detector to indicate a detection of a fault, a sensor to provide a speed signal indicative of whether a speed of a PM motor is greater than a transition speed, and a controller. The controller is operable to apply either an open-circuit response or a short-circuit response to the multi-phase inverter. The open-circuit response is applied when the speed of the PM motor is greater less than the transition speed and a fault is detected. The short-circuit response is applied when the speed of the PM motor is less greater than the transition speed and the fault is detected. The transition speed is either a fixed predetermined speed or an adjusted predetermined speed.