Dual Motor Drive Assembly With Threshold Torque Sharing
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Solution Overview
Problem
Conventional dual motor drive assemblies in handwheel actuators for vehicles face issues with high electrical losses and mechanical stress due to motors operating at maximum torque, leading to overheating and reduced durability, as they often require one motor to run at 100% capacity to meet torque demands.
Innovation Solution
A dual motor drive assembly with a controller that allocates torque demands below the maximum output for each motor, allowing both motors to work together before reaching 100% capacity, reducing electrical losses and mechanical stress by adjusting torque directions and demands based on threshold values that can be fixed or variable depending on operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If one motor runs at maximum torque output to meet high torque demands, then the required torque can be provided, but electrical losses and mechanical stress increase significantly
Solution Approach 1:
The patent divides the torque demand into two separate motors instead of using one motor at maximum capacity. Each motor operates at a threshold torque demand (e.g., 50% of maximum), and when both motors operate at their threshold levels, the combined torque meets the total demand without either motor reaching maximum output, thereby reducing electrical losses proportional to the square of the current.
2Power
If one motor runs at maximum torque output, then the required torque can be provided, but mechanical stress on components increases
Solution Approach 1:
The torque demand is segmented across two motors, each operating at a reduced threshold level (e.g., 50% of maximum). This distribution reduces the mechanical stress on individual motor components and associated mechanical parts, as stress is proportional to the torque applied by each motor rather than one motor bearing the full load.
3Power
If motors operate at maximum output torque for extended periods, then high torque demands are met, but overheating occurs and reliability decreases
Solution Approach 1:
By segmenting the torque demand across two motors operating at threshold levels rather than one motor at maximum capacity, the thermal load on each motor is reduced. Since electrical losses and heat generation are proportional to the square of the current, operating at lower currents significantly reduces overheating risk and extends the duration motors can operate reliably without derating.
Solution Approach 2:
The system changes the operating parameters of the motors by introducing a threshold torque demand (e.g., 50% of maximum) rather than allowing motors to operate continuously at maximum output. This parameter change enables sustained operation without overheating while still meeting variable torque demands through coordinated control of multiple motors.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach extends the range of torque demands that can be met without either motor running at maximum output, reducing electrical losses, mechanical stress, and the risk of overheating, thereby enhancing the assembly's reliability and durability.
Implementation Method 1
a first motor (10) with a rotor (101) and stator (102), and a second motor (11) with a rotor (111) and stator (112)
Data Source
AI summary
A dual motor drive assembly includes a housing, a shaft rotatably mounted with respect to the housing, a first gear connected to and configured to rotate with the shaft, first and second motors, each having an output driving a respective output gear. The output gears are engaged with the first gear. The dual motor drive assembly also includes a controller for allocating torque demands to each of the first and second motors, wherein a threshold torque demand is assigned to each motor, the threshold torque demand being lower than the maximum torque output of the motor.