Electric Vehicle Motor Torque Control for Shifting Precision
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Solution Overview
Problem
Existing motor torque control systems for electric vehicles with transmissions lack precision in shifting control, leading to reduced shifting quality due to the inability to generate negative torque and rely on engineer experience for torque determination.
Innovation Solution
A motor torque control method that determines power-on up-shift and power-off down-shift strategies by calculating target angular acceleration and corresponding maximum and minimum motor torque values, allowing for precise control of motor output torque to improve shifting quality and responsiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If motor torque control is based on engineer experience rather than theoretical calculations, then the control system is simpler to implement, but shifting precision and quality deteriorate
Solution Approach 1:
The patent applies parameter changes by transitioning from experience-based torque values to theoretically calculated torque parameters. The controller calculates target angular acceleration and uses it to determine maximum and minimum motor torque values through specific formulas, changing the control parameter from empirical to calculated, thereby improving shifting precision.
Solution Approach 2:
The patent implements feedback control by continuously monitoring the actual motor torque and comparing it with the calculated target torque values. The controller adjusts the motor torque in real-time based on the difference between actual and target values, ensuring precise shifting control through closed-loop feedback.
2Ease of operation
If the motor generates only positive torque like internal combustion engines, then the control system is simpler, but shifting quality and responsiveness deteriorate
Solution Approach 1:
The patent applies dynamics by enabling the motor to dynamically switch between positive and negative torque generation. The controller determines the direction and magnitude of torque based on shifting requirements, allowing the motor to adapt its torque characteristics dynamically, which improves shifting responsiveness and quality.
Solution Approach 2:
The patent changes the torque parameter from unidirectional (positive only) to bidirectional (positive and negative). By calculating and controlling both maximum positive torque and minimum negative torque values based on target angular acceleration, the system achieves faster and more precise shifting performance.
3Loss of time
If clutch control of the transmission is used to reduce shifting time, then shifting speed improves, but shifting precision and quality deteriorate
Solution Approach 1:
The patent replaces mechanical clutch control with electrical motor torque control. Instead of relying on mechanical clutch engagement and disengagement to manage shifting, the system uses the motor's ability to generate positive and negative torque to directly control the shifting process, improving both precision and quality.
Solution Approach 2:
The patent changes the control parameter from clutch engagement timing to motor torque magnitude and direction. By calculating optimal torque values based on target angular acceleration and using the motor's bidirectional torque capability, the system achieves precise control over shifting speed and quality simultaneously.
Data Source
AI summary
Disclosed herein is a motor control system and method for a vehicle with a transmission comprising for improving the quality of shifting, by improving precision in shifting control with precise and active motor torque control by calculating a maximum and a minimum motor torque in response to determining a power-on up-shift for increasing a shifting gear and a power-off down-shift for decreasing the shifting gear in shifting of the vehicle.