Hub Motor Torque Vectoring With MCU-Based Slip Ratio Control
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Solution Overview
Problem
In hub motor drive systems, existing torque vectoring systems face challenges in evaluating torque distribution and change, leading to inadequate real-time torque calculation and protection functions, particularly due to direct calculation by the vehicle control unit without considering current changes in motor control units, resulting in mismatched wheel motor operations and insufficient slip ratio control.
Innovation Solution
A torque vectoring system that includes a drive module for measuring specified parameters and a control module, which calculates target motor torque for each wheel motor based on total torque requests and steering angles, using a motor control unit instead of a vehicle control unit, allowing for improved real-time calculations and evaluation of torque distribution, with a shared cooling loop and prioritization of slip ratio control modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the vehicle control unit directly calculates target motor torque without considering current changes in motor control units, then the calculation process is simple, but the torque distribution evaluation capability is insufficient and real-time performance is inadequate
Solution Approach 1:
The system divides the control architecture into multiple independent control units, each responsible for specific wheel motor control. The motor control units are segmented from the vehicle control unit, with each having independent current detection and torque calculation capabilities. This segmentation enables distributed torque distribution evaluation while maintaining overall system coordination.
Solution Approach 2:
The system implements feedback mechanisms where motor control units continuously detect current changes and feed this information back to the vehicle control unit. The vehicle control unit receives real-time current data from each motor control unit and uses this feedback to dynamically adjust torque distribution calculations, ensuring accurate evaluation of torque distribution and change.
2Device complexity
If the vehicle control unit directly calculates target motor torque, then the control architecture is centralized, but one wheel motor may be in drive mode while the other is in power generation mode causing protection function interference
Solution Approach 1:
The control system is segmented into independent motor control units for each wheel motor, allowing each unit to independently manage its motor's operating mode (drive or power generation). This segmentation prevents conflicts where one motor is in drive mode while another is in power generation mode, as each control unit can make independent decisions based on real-time conditions.
Solution Approach 2:
The system dynamically adjusts the operating modes of individual wheel motors based on real-time vehicle conditions and torque requirements. Each motor control unit can switch between drive and power generation modes independently, allowing the system to optimize performance and avoid protection function interference that would occur with fixed centralized control decisions.
3Speed
If the vehicle control unit calculates target motor torque without real-time current data, then the calculation is faster, but the slip ratio control cannot be achieved
Solution Approach 1:
The system implements real-time feedback of current data from each motor control unit to the vehicle control unit. This feedback mechanism provides the necessary current information for slip ratio calculation and control while maintaining fast response times. The continuous current data flow enables accurate slip ratio control without significantly impacting torque calculation speed.
Solution Approach 2:
The motor control units continuously detect and prepare current data in advance, maintaining a real-time record of current changes. This preliminary action ensures that when the vehicle control unit needs to calculate target motor torque, the current data is already available, enabling both fast calculation and accurate slip ratio control without delay.
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 solution enhances real-time torque vectoring, prevents mismatched operations, and prioritizes safety by reducing target motor torque when slip ratios exceed thresholds, improving system simulation and integration feasibility by decentralizing calculations and protecting components more effectively.
Implementation Method 1
the power output unit and each wheel motor of the vehicle may share a cooling loop, the cooling loop may be provided with a pump for driving a cooling medium to circulate in the cooling loop
Data Source
AI summary
A torque vectoring system for a hub motor drive system uses a motor control unit instead of a vehicle control unit to conduct torque vectoring calculation, so that a target motor torque can be obtained more reasonably and the real-time property is improved. In addition, as it is unnecessary to conduct calculation with the vehicle control unit, torque distribution and torque change can be evaluated on a testbed of the motor control unit prior to integrating the torque vectoring system into the vehicle.