US-12623550-B2 - Dual motor torque monitoring

US12623550B2US 12623550 B2US12623550 B2US 12623550B2US-12623550-B2

Abstract

Systems and methods for dual motor torque monitoring are provided. One method includes determining torque errors for a first motor, determining torque errors for a second motor, determining combined torque errors for the first motor and the second motor, determining a torque fault based on the torque errors for the first motor, the torque errors for the second motor and the combined torque errors, and executing a predetermined function based on the torque fault. In one example, the predetermined function may include transmitting a torque fault notification message from a motor control unit processor to a vehicle control system processor.

Inventors

Armin Teymouri
Younes Sangsefidi
Mehrdad Yazdanian
CHIA-CHOU YEH

Assignees

RIVIAN IP HOLDINGS, LLC

Dates

Publication Date: 20260512
Application Date: 20240109

Claims (19)

1 . A method for dual motor torque monitoring by a motor controller unit, the method comprising: determining, by a first processor, a first motor speed and storing the first motor speed in a memory; determining, by a second processor, a second motor speed and storing the second motor speed in the memory; receiving, by a supervisory processor, a first torque command for the first motor from a vehicle control system processor over a communication link; receiving, by the supervisory processor, a second torque command for the second motor from the vehicle control system processor over the communication link; determining, by the supervisory processor, torque errors for a first motor based at least in part on the first motor speed stored in the memory and the first torque command; determining, by the supervisory processor, torque errors for a second motor based at least in part on the second motor speed stored in the memory and the second torque command; determining, by the supervisory processor, combined torque errors for the first motor and the second motor; determining, by the supervisory processor, a torque fault based on the torque errors for the first motor, the torque errors for the second motor, and the combined torque errors; and transmitting, by the supervisory processor, a torque fault notification message to the vehicle control system processor over the communication link, the torque fault notification message including the torque fault.
2 . The method of claim 1 , wherein: the torque errors for the first motor include a first model torque error and a first loss torque error; and the torque errors for the second motor include a second model torque error and a second loss torque error.
3 . The method of claim 2 , wherein: the first model torque error is determined based on a first current model for the first motor; the first loss torque error is determined based on a first voltage model for the first motor; the second model torque error is determined based on a second current model for the second motor; and the second loss torque error is determined based on a second voltage model for the second motor.
4 . The method of claim 2 , wherein: the first model torque error is determined based on the first torque command, a first model torque estimate, and a first model torque limit; and the first loss torque error is determined based on the first torque command, the first model torque estimate, a first loss torque estimate, and a first loss torque limit.
5 . The method of claim 4 , wherein: the second model torque error is determined based on the second torque command, a second model torque estimate, and a second model torque limit; and the second loss torque error is determined based on the second torque command, the second model torque estimate, a second loss torque estimate, and a second loss torque limit.
6 . The method of claim 1 , wherein the combined torque errors for the first motor and the second motor include a combined model torque error and a combined loss torque error.
7 . The method of claim 6 , wherein: the combined model torque error is determined based on the first torque command, a first model torque estimate, the second torque command, and a second model torque estimate; and the combined loss torque error is determined based on the first torque command, the first model torque estimate, a first loss torque estimate, the second torque command, the second model torque estimate, and a second loss torque estimate.
8 . The method of claim 7 , wherein: the combined model torque error is further determined based on a first model torque limit and a second model torque limit; and the combined loss torque error is further determined based on a first loss torque limit, a second loss torque limit, a first motor speed, a second motor speed, and a motor speed limit.
9 . A motor controller unit (MCU), comprising: a first processor, coupled to a first motor and a memory, the first processor configured to determine a first motor speed and store the first motor speed in the memory, wherein the memory comprises one or more memories; a second processor, coupled to a second motor and the memory, the second processor configured to determine a second motor speed and store the second motor speed in the memory; and a supervisory processor, coupled to the first processor, the second processor, and the memory, the supervisory processor configured to: receive, from a vehicle control system processor over a communication link, a first torque command for the first motor; receive, from the vehicle control system processor over the communication link, a second torque command for the second motor; determine torque errors for the first motor based at least in part on the first motor speed stored in the memory and the first torque command, determine torque errors for the second motor based at least in part on the second motor speed stored in the memory and the second torque command, determine combined torque errors for the first motor and the second motor, determine a torque fault based on the torque errors for the first motor, the torque errors for the second motor, and the combined torque errors, and transmit a torque fault notification message to the vehicle control system processor over the communication link, the torque fault notification message including the torque fault.
10 . The MCU of claim 9 , wherein: the torque errors for the first motor include a first model torque error and a first loss torque error; the first model torque error is determined based on the first torque command, a first model torque estimate, and a first model torque limit; and the first loss torque error is determined based on the first torque command, the first model torque estimate, a first loss torque estimate, and a first loss torque limit.
11 . The MCU of claim 10 , wherein: the first model torque error is determined based on a current model for the first motor; the first loss torque error is determined based on a voltage model for the first motor.
12 . The MCU of claim 10 , wherein: the torque errors for the second motor include a second model torque error and a second loss torque error; the second model torque error is determined based on the second torque command, a second model torque estimate, and a second model torque limit; and the second loss torque error is determined based on the second torque command, the second model torque estimate, a second loss torque estimate, and a second loss torque limit.
13 . The MCU of claim 12 , wherein: the second model torque error is determined based on a current model for the second motor; and the second loss torque error is determined based on a voltage model for the second motor.
14 . The MCU of claim 12 , wherein: the combined torque errors for the first motor and the second motor include a combined model torque error and a combined loss torque error; the combined model torque error is determined based on the first torque command, the first model torque estimate, the first model torque limit, the second torque command, the second model torque estimate, and the second model torque limit; and the combined loss torque error is determined based on the first torque command, the first model torque estimate, the first loss torque estimate, the first loss torque limit, the second torque command, the second model torque estimate, the second loss torque estimate, the first motor speed, and the second motor speed.
15 . A method for dual motor torque monitoring by a motor controller unit, the method comprising: determining, by a first processor, a first motor speed and storing the first motor speed in a memory; determining, by a second processor, a second motor speed and storing the second motor speed in the memory; receiving, by a supervisory processor, a first torque command for the first motor from a vehicle control system processor over a communication link; receiving, by the supervisory processor, a second torque command for the second motor from the vehicle control system processor over the communication link; determining, for a first motor, a first model torque error, and a first loss torque error; determining, for a second motor, a second model torque error, and a second loss torque error; determining a combined model torque error, and a combined loss torque error; determining a torque fault based on the first model torque error, the first loss torque error, the second model torque error, the second loss torque error, the combined model torque error, and the combined loss torque error; and transmitting a torque fault notification message from the supervisory processor to the vehicle control system processor over the communication link, the torque fault notification message including the torque fault.
16 . The method of claim 15 , wherein: the first model torque error is determined based on the first torque command, a first model torque estimate, and a first model torque limit; and the first loss torque error is determined based on the first torque command, the first model torque estimate, a first loss torque estimate, and a first loss torque limit.
17 . The method of claim 16 , wherein: the second model torque error is determined based on the second torque command, a second model torque estimate, and a second model torque limit; and the second loss torque error is determined based on the second torque command, the second model torque estimate, a second loss torque estimate, and a second loss torque limit.
18 . The method of claim 17 , wherein: the first model torque error is determined based on a first current model for the first motor; the first loss torque error is determined based on a first voltage model for the first motor; the second model torque error is determined based on a second current model for the second motor; and the second loss torque error is determined based on a second voltage model for the second motor.
19 . The method of claim 17 , wherein: the combined model torque error is determined based on the first torque command, the first model torque estimate, the first model torque limit, the second torque command, the second model torque estimate, and the second model torque limit; and the combined loss torque error is determined based on the first torque command, the first model torque estimate, the first loss torque estimate, the first loss torque limit, the second torque command, the second model torque estimate, the second loss torque estimate, a first motor speed, and a second motor speed.

Description

INTRODUCTION The present disclosure relates to electric vehicles (EVs). More particularly, the present disclosure relates to dual motor torque monitoring for EVs. SUMMARY Embodiments of the present disclosure advantageously provide systems and methods for dual motor torque monitoring. In certain embodiments, a method for dual motor torque monitoring includes determining torque errors for a first motor, determining torque errors for a second motor, determining combined torque errors for the first motor and the second motor, determining a torque fault based on the torque errors for the first motor, the torque errors for the second motor and the combined torque errors, and executing a predetermined function based on the torque fault. In certain embodiments, the predetermined function includes transmitting a torque fault notification message from a motor control unit processor to a vehicle control system processor. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 depicts a diagram of an example electric vehicle, in accordance with embodiments of the present disclosure. FIG. 2 presents a block diagram of example components of an EV, in accordance with embodiments of the present disclosure. FIG. 3 presents a block diagram illustrating an exemplary dual motor torque monitoring software architecture, in accordance with embodiments of the present disclosure. FIGS. 4A, 4B present block diagrams illustrating exemplary functionality for a torque monitor (TM) module for motor 1, in accordance with embodiments of the present disclosure. FIGS. 5A, 5B present block diagrams illustrating exemplary functionality for a TM module for motor 2, in accordance with embodiments of the present disclosure. FIGS. 6A, 6B present block diagrams illustrating exemplary functionality for a TM module for motor 1 and motor 2, in accordance with embodiments of the present disclosure. FIG. 7 presents a block diagram illustrating exemplary functionality for a TM module for fault triggering, in accordance with embodiments of the present disclosure. FIG. 8 depicts flow chart illustrating functionality associated with dual motor torque monitoring, in accordance with embodiments of the present disclosure. DETAILED DESCRIPTION Generally, electric vehicles (EVs) may be classified into different categories based on the architecture of the propulsion system. All-electric vehicles (AEVs), also known as full-electric vehicles (FEVs) or battery electric vehicles (BEVs), are propelled by AC motors that are connected to gearboxes that drive the wheels. The AC motors are powered by a DC battery pack that must be periodically recharged at a charging station. Hybrid electric vehicles (HEVs) and plug-in hybrid electric vehicles (PHEVs) are also propelled by AC motors that are powered by a DC battery pack, but additionally incorporate an internal combustion engine that drives a generator to recharge the DC battery pack. Some HEVs and PHEVs may also connect the internal combustion engine to a common gearbox or transmission to drive the wheels. An electric drive unit (EDU) combines an AC motor, a gearbox, and a motor control unit (MCU) into a single mechanical package. The MCU includes, inter alia, a processor, a controller, etc., and an inverter that converts DC power provided by the battery pack to AC power provided to the AC motor. The inverter controls the speed and torque of the AC motor by adjusting the AC motor voltage frequency (proportional to speed) and the AC motor current (proportional to torque). Many EVs use Permanent-Magnet Synchronous Motors (PMSMs), which are powered by continuous sinusoidal AC current and use permanent magnets in the rotor (whose N-S axes may be axially aligned with the output shaft) and electromagnets in the stator. Other EVs use asynchronous AC induction motors, which use electromagnets in the both the rotor and the stator. Synchronous reluctance motors (SynRM) and internal permanent-magnet IPM SynRMs may also be used. A single-motor EV provides either front-wheel drive or rear-wheel drive, and has a front EDU connected to the front wheels or a rear EDU connected to the rear wheels, respectively. The EDU has a single AC motor, a single gearbox connected to a limited-slip differential, and a single MCU. The differential is connected to each front wheel or each rear wheel. A dual-motor EV provides all-wheel drive, and has a front EDU connected to the front wheels and a rear EDU connected to the rear wheels. Each EDU has a single AC motor, a single gearbox connected to a limited-slip differential, and a single MCU. The front EDU differential is connected to each front wheel, and the rear EDU differential is connected to each rear wheel. A quad-motor EV also provides all-wheel drive, and has a front dual motor EDU connected to the front wheels (front axle), and a rear dual motor EDU connected to the rear wheels (rear axle). In other words, a quad-motor EV has two motors per axle. Each dual motor EDU has two AC motors, two gearboxes, and tw