Dual Motor Torque Allocation for Thermal-Limited Steering Drives
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Solution Overview
Problem
Conventional dual motor drive assemblies in steer-by-wire systems face challenges in managing temperature differences between motors, which can lead to overheating and reduced performance.
Innovation Solution
A dual motor drive assembly with a torque allocation arrangement that adjusts torque demands based on temperature measurements, allowing for a maximum total torque that is the sum of individual motor torque limits, and switching between opposing and same-direction torque modes based on a threshold total torque value adjusted by temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If thermal management limits motor torque demand to prevent overheating, then motor temperature is controlled, but total torque output is reduced
Solution Approach 1:
The patent combines the thermal management functions of two motors into a unified system where torque demands are coordinated based on individual temperature measurements. When one motor is thermal limited, the other motor compensates by providing additional torque, merging their capabilities to maintain total torque output while controlling individual motor temperatures.
Solution Approach 2:
The system dynamically changes the torque demand parameter for each motor based on its temperature measurement. The torque allocation arrangement continuously adjusts torque demands in response to temperature changes, allowing motors to operate at optimal power levels without exceeding thermal limits.
2Temperature
If torque is allocated to balance motor temperatures, then thermal management is improved, but torque response time may be delayed
Solution Approach 1:
The system implements continuous feedback by measuring individual motor temperatures and using these measurements to dynamically adjust torque allocations. The torque allocation arrangement receives temperature feedback from both motors and automatically redistributes torque demands to balance thermal loads, creating a closed-loop control system that responds in real-time to thermal conditions.
Data Source
AI summary
A dual motor drive assembly comprising a housing, a shaft rotatably mounted to the housing, a first gear rotatably connected to the shaft, first and second motors, each having an output driving a respective output gear, the output gears being engaged with the first gear, a torque allocation arrangement for allocating torque demands to each of the first and second motors, a measurement arrangement for measuring first and second temperature relating to the first and second motors respectively, a torque limit allocation arrangement for allocating a maximum torque limit based on the first and second temperature respectively, wherein a maximum total torque is equal to the sum of maximum torque limits of the first and second motors, wherein in a first mode the allocated torque demand to each of the motors is to provide opposing torques to the shaft, and in a second mode to provide torques in the same direction to the shaft, wherein the torque demand allocations change from the first mode to the second mode at a threshold total torque value, and the threshold total torque value is adjustable based on the maximum total torque.