Gm Global Technology Operations LLC

Brent S Gagas

Brian A Welchko

Kerrie M Spaven

Yiran Hu

Song He

Dwarakanath V Simili

Brian J Gallert

Xin Jing

Caleb W Secrest

Bojian Cao

Wei Wang

Shifang Li

Shiming Duan

Anno Yoo

Daniel J Berry

Vinod Chowdary Peddi

Aubrey Walter Downs, Jr

Ruixing Long

Todd M York

Tanvi Nagarale

Christopher L Jones

James M Faucett

Vehicles and related systems and monitoring methods are provided for detecting a loss of isolation on one side of a power converter. One method involves monitoring a normalized voltage input to a power conversion module coupled to the electric motor, in response to the normalized voltage exceeding a diagnostic activation threshold, determining a first number of instances of a range between successive extremas of the normalized voltage exceeding a loss of isolation range threshold over a diagnostic window of time, and automatically initiating a remedial action when the first number is greater than a loss of isolation detection threshold.

Vehicle systems and loss of isolation detection methods

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

Presented are control systems for operating dual-independent drive unit (DIDU) powertrains, methods for making/operating such systems, and electric-drive vehicles with fault management and mitigation for DIDU axles. A method of operating a motor vehicle with a DIDU axle includes monitoring first and second drive units (DU) that are independently operable to drive respective road wheels via respective axle shafts of the DIDU axle. A vehicle controller receives an indication of a fault condition in the first DU from a fault sensing module and responsively determines a fault type for the fault condition. The controller ascertains the vehicle's current speed and determines a respective torque limit for each of the DIDU drive units based on the fault type and current vehicle speed. Torque output of the first DU is concomitantly constrained to a first torque limit while torque output of the second DU is constrained to a second torque limit.

Intelligent vehicles and control logic for managing faults for dual-independent drive unit axle powertrains

A control system for a rotary electric machine includes an inverter including a plurality of power switches, a heat exchanger, first temperature sensors arranged to monitor the power switches, a second temperature sensor arranged to monitor the heat exchanger, and a controller. An expected power loss is determined based upon electric current, switching functions, and electrical characteristics of the power switches. A plurality of power capacity terms are determined based upon the expected power loss in the inverter, the temperatures of the power switches, and the temperature of the heat exchanger. The inverter is controlled based upon the aforementioned power capacities.

A diagnostic system for a vehicle includes a vehicle system configured to operate the vehicle in a normal operating mode and a boosted mode. In the boosted mode, the vehicle system increases at least one of a maximum motor torque, a maximum engine torque, and a maximum battery power available to the vehicle. A wear estimation module is configured to collect wear data associated with a component of the vehicle while being operated in the boosted mode, estimate, based on the collected wear data, wear of the component caused by being operated in the boosted mode, and generate a prediction of a remaining lifetime of the component based on the estimated wear of the component.

Methods and apparatus for propulsion system prognostics due to boosted operation

A method for controlling transient operation of a variable flux machine (VFM) includes, during a shunt angle transition, receiving a commanded and measured shunt angle when operating in a predetermined operating region, e.g., maximum torque per ampere or field weakening. The method includes calculating d-axis and q-axis delta current terms (ΔIand ΔI) required to maintain an output torque level of the VFM through a duration of the shunt angle transition, then applying the required ΔIand ΔIterms as feed-forward terms to adjust a d-axis current (I) term and a q-axis current (I) term from a respective lookup table. In this manner the controller maintains the output torque level of the VFM during the shunt angle transition. An electric powertrain includes the VFM, a TPIM, and the controller. A PM machine may be controlled by substituting temperature for shunt angle.

Open-loop control for transient operation of a rotary electric machine

The disclosure includes a control system for a multi-phase electric machine that includes an inverter configured to transfer electric energy from a rechargeable energy storage device (RESS), and phase current sensors. A controller includes an executable instruction set to monitor, via the phase current sensors, the phase currents, and detect that one of the phase currents is outside a linear measurement range of a respective one of the phase current sensors. An extrapolated current for the respective one of the phase current sensors is determined based upon the phase currents from others of the phase current sensors. A current extrapolation routine evaluates the respective one of the phase current sensors. A fault is detected in the respective one of the phase current sensors based upon the current extrapolation routine and the extrapolated current.

Method and system for monitoring a current sensor

An electric drive system, method and apparatus includes a rechargeable energy storage unit, a power inverter, and a rotary electric machine. Transfer of electrical power between the rechargeable energy storage unit and the rotary electric machine is governed by a pulse width modulation (PWM) switching frequency, which is one of a non-six-step switching mode or a six-step switching mode. Executable instructions determine a rotational speed, a torque command, a torque direction, a bus voltage, and a hysteresis band, determine a modulation index command in response to the rotational speed, the torque command, the torque direction, and the bus voltage, and command operation of the rotary electric machine in one of the non-six-step switching mode or the six-step switching mode employing the modulation index command.

Electric drive system and method

Control of an AC motor includes rotation over an operating speed range with the output from an inverter by operating the inverter at switching frequencies that vary in proportion to rotor speed. The operating speed range is parsed into a plurality of speed regions and the switching frequencies within each operating speed region may correspond to a respective pulse ratio that is different from the respective pulse ratio corresponding to an adjacent speed region.

Electric vehicle sound enhancement

A method for controlling operation of a rotary electric machine includes receiving, via a bandwidth-partitioning harmonic compensation regulator (HCR) of a controller, a commanded torque and rotational speed of the electric machine, and calculating, via the HCR in response to enabling conditions, a dq harmonic compensation current and a dq harmonic compensation voltage for one or more predetermined harmonic orders using the commanded torque and the rotational speed. The harmonic compensation current and voltage cancel torque ripple and current ripple in the one or more predetermined harmonic orders. The method may include injecting an acoustic tone at a predetermined harmonic order. The method additionally includes adding the dq harmonic compensation current and voltage to a dq current and voltage command, respectively, to generate adjusted dq current and voltage commands. The electric machine is then controlled using the adjusted dq current and voltage commands.

Bandwidth-partitioning harmonic regulation for improved acoustic behavior of an electric drive system

A method for increasing a default electric stall torque limits in a motor vehicle having an electrified powertrain inclusive of a traction power inverter module (TPIM) connected to an electric traction motor includes receiving vehicle level inputs via a controller. The controller is programmed with the default electric stall torque limits. The method includes selecting an inverter control strategy, via the controller, as a selected inverter control strategy in response to the vehicle level inputs, the strategy including temporarily increasing the default electric stall torque limits while applying a pulse width modulation (PWM) type at a corresponding PWM switching frequency. The method also includes controlling an output state of the TPIM and the electric traction motor over a calibrated duration, via the controller, using the selected inverter control strategy. A motor vehicle includes the controller, road wheels, TPIM, and traction motor.

Electric drive stall torque enhancement based on vehicle level inputs

An electric drive system includes a rechargeable energy storage unit, a power inverter, an electric motor and a controller having a processor and tangible, non-transitory memory on which instructions are recorded. A transfer of electrical power between the rechargeable energy storage unit and the electric motor is governed by a pulse width modulation (PWM) switching frequency. The controller is configured to determine a current switching frequency based in part on a PWM type, a PWM switching frequency style and an inverter direct current voltage. A PWM scalar is determined based in part on the current switching frequency and a maximum value of a control reference frequency. The controller is configured to transmit a command signal to regulate the transfer of electrical power based in part on the PWM scalar, the PWM switching frequency being proportional to a product of the PWM scalar and the control reference frequency.

Electric drive assembly with dynamic control of pulse width modulation switching

Presented are high-voltage electrical systems with optimized pulse width modulation (PWM) control, methods for making/using such systems, and vehicles with enhanced electric drive capabilities via PWM type and frequency control. A method of operating an electrical system includes an electronic controller determining a PWM region layout with multiple PWM regions arranged in a torque-speed curve calibrated to an electric motor and power inverter. The controller selects one of the PWM regions based on a speed and torque of the motor, and selects a PWM type based on this selected PWM region. The controller selects a PWM switching frequency style based on the selected PWM region, and selects a PWM switching frequency based on the selected PWM region, switching frequency style, and PWM type. The controller commands a power inverter to regulate transfer of electrical power between a rechargeable battery and the motor based on the PWM type and switching frequency.

Enhanced electric drive vehicle operation via pulse width modulation (PWM) type and frequency control

A method for controlling transient operation of a rotary electric machine in an electric powertrain or other electrical system includes, during a shunt angle transition occurring during a maximum torque per ampere (MTPA) control region, determining an estimated output torque of the electric machine via a torque estimation block using d-axis and q-axis current commands and an additional value, i.e., an actual shunt angle or a machine temperature. The method includes subtracting the estimated output torque from a commanded output torque to derive an adjusted commanded torque value or torque error, and calculating, from the torque error, a delta d-axis current command and a delta q-axis current command. The method includes adjusting d-axis and q-axis current commands using the delta commands to produce adjusted d-axis and q-axis current commands, which are then used as closed-loop feedback control terms by the torque estimation block.

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Ferndale, MI, United States of America

Brent S Gagas