Gm Global Technolgoy Operations, Inc.

Brian J Gallert

Brian A Welchko

Brent S Gagas

Jiyu Zhang

Young Joo Lee

Kerrie M Spaven

Khwaja M Rahman

Wei D Wang

Anno Yoo

Daniel J Berry

Paul F Turnbull

Timothy J Alfermann

Matthew D Laba

Kibok Lee

Brian Schulze

Michael Duncan Swartz

Stephen M Garza

A method and system are contemplated for determining a final speed and position of a motor used in an electric vehicle. The final speed and position is calculated as a function of a sensed position when a resolver of a position system is available and as a function of a sensorless position when the resolver is unavailable.

Sensorless backup for motor speed and position

Examples described herein provide a computer-implemented method that includes receiving data from an electric motor of a vehicle, the electric motor comprising a stator and a rotor. The method further includes performing a motor health degradation analysis to determine whether a degradation of the electric motor has occurred. The method further includes performing a stator health degradation analysis to determine that a stator degradation has occurred. The method further includes performing a rotor health degradation analysis to determine that a rotor degradation has occurred. The method further includes implementing a corrective action for the vehicle e responsive to determining that the degradation of the electric motor has occurred and at least one of the stator degradation or the rotor degradation has occurred.

Detecting degradation within electric motors

A method of monitoring a propulsion system of a vehicle includes determining a health indicator from a diagnostic signal based on electrical outputs from a resolver connected to an electric motor of the propulsion system, the diagnostic signal related to a resolver offset and/or a resolver wobble, calculating a reference value based on values of the health indicator determined during a first time period, and monitoring the health indicator over a second time period, where the monitoring includes continuously or periodically calculating a trend value of the health indicator over a plurality of cycles. The method also includes comparing each trend value to the reference value and estimating a difference between the trend value and the reference value for each cycle, predicting whether a fault will occur based on the difference, and based on the predicting indicating that a fault will occur, outputting a fault indication.

Prediction of resolver malfunctions

A method, apparatus, and control system are described for operating a multiphase motor drive system including a rotary electric machine and an inverter. An AC choke filter is arranged proximal to output leads from the inverter. A reference temperature associated with the AC choke filter is determined along with an operating point of the electric machine. Operation of the inverter is controlled based upon a temperature of the AC choke filter, the reference temperature, and an operating point of the electric machine. This includes modifying a switching frequency and a PWM type in a manner that reduces the AC choke filter temperature by reducing the occurrence of switching events to protect the AC choke filter based on temperature feedback.

Method and system for controlling common mode electric current in an electric machine

The concepts described herein provide a method, apparatus, and system for controlling an inverter by modifying duty cycles of the PWM control signals in a manner that achieves a minimum duration between consecutive switching events in the inverter, which serves to reduce common mode current in the bearing(s) of an attached rotary electric machine. To minimize the effect of additional current and voltage ripple into the system, the minimum switching duration is defined in relation to a modulation index and geometric location near the sector boundaries of the respective inverter voltage space vector diagram.

Method and system for controlling an electric machine

A diagnostic system for a resolve of a motor and a method of diagnosing the resolver. The diagnostic system includes an x-phase winding, a y-phase winding, and a processor. The x-phase winding generates an x-phase voltage and the y-phase winding generates a y-phase voltage. The processor obtains the x-phase voltage and the y-phase voltage, determines an adaptive cosine envelope from the x-phase voltage and an adaptive sine envelope from the y-phase voltage, determines an adaptive magnitude from the adaptive sine envelope and the adaptive cosine envelope, determines a magnitude average based on the adaptive magnitude, determines a fault of the resolver when a ratio of the adaptive magnitude and the magnitude average is greater than a threshold, and transmits a signal based on the fault.

Adaptive resolver envelope diagnostic

An electric powertrain system includes an electric machine having a rotor and stator. The stator has multiple phase legs, each respective one of which includes a single phase lead connected to two or more parallel stator windings. The stator thus has multiple phase leads collectively conducting phase currents. A rotary output member is connected to the rotor and connectable to a load. A traction power inverter module (TPIM) is electrically connected to the phase legs. Current sensors collectively measure the phase currents. Each respective current sensor is connected to a different phase lead. A controller in communication with the current sensors and the TPIM, in response to a commanded current and the measured phase currents, detects a threshold variation in the measured phase currents indicative of a phase current imbalance fault, and selectively changes a thermodynamic state of the electrified powertrain in response to the fault.

Current imbalance fault mitigation for rotary electric machine with parallel stator windings

In an example, a system is disclosed. The system includes a rotor position estimation module configured to generate an adjustment signal to adjust a desired torque signal for a motor. The rotor position estimation module includes a sensor offset estimation module configured to estimate an offset position of a sensor based on (1) a motor current signal indicative of a current to rotate a rotor within the motor, (2) a motor voltage signal indicative of a voltage applied to a power inverter that provides the current to the motor, and (3) a motor parameter. The sensor can be disposed on the rotor. The rotor position estimation module also includes a speed adjustment module configured to generate the adjustment signal based on the estimated offset position.

System and method for estimating rotor sensor offset

An electric motor includes a rotor and a stator. The stator is fixed with respect to the drive-unit housing and includes windings, and the rotor is configured to rotate inside the stator about an axis. An air gap is defined between the rotor and the stator. The electric motor also includes an end-ring fixed to the rotor for rotation therewith. The electric motor is cooled by gravity feed via a fluid flowing onto and past the stator windings, from the windings to the rotor, and from the rotor back to the stator. The end-ring includes an annular channel configured to catch the fluid flowing from the windings to the rotor and divert the fluid away from the air gap as the fluid flows from the rotor back to the stator, thereby limiting spin losses in the electric motor. An electro-mechanical drive-unit employing the above-described electric motor is also disclosed.

Electric motor

A hub assembly for an electric machine includes a rotor hub and a machine rotor. Rotation of the machine rotor generates an electromagnetic (EM) field. The hub assembly includes a resolver rotor that encodes an angular position of the machine rotor as a set of resolver signals. An EM field barrier ring between the resolver rotor and the rotor hub adds a magnetic barrier between the machine rotor and the resolver rotor to reduce noise in the resolver signals. The resolver rotor may be bonded to the EM field barrier ring. The EM field barrier ring may have an L-shaped cross section, and may be press-fitted into a pocket of the rotor hub. A vehicle includes a transmission having an input member and an electric machine having a rotor shaft connected to the input member of the transmission. The electric machine includes the hub assembly noted above.

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Waterford, MI, United States of America

Brian J Gallert