Electric Vehicle Torque Control Preventing Backlash NVH
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Solution Overview
Problem
Current drive systems in electric vehicles face challenges in preventing backlash and associated noise, vibration, and harshness (NVH) issues due to rapid torque changes, which affect responsiveness and safety, as existing methods only compensate for backlash rather than preventing its occurrence.
Innovation Solution
A torque control method that determines required torque based on vehicle state and performs front and rear wheel torque distribution to maintain positive torque values, avoiding the backlash band and minimizing direction changes, thereby preventing backlash and enhancing responsiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If torque change rate is set to be high to improve acceleration responsiveness, then acceleration responsiveness is improved, but backlash and NVH issues occur in the drive system
Solution Approach 1:
The control method performs preliminary action by maintaining a minimum positive torque threshold before backlash occurs. The controller continuously monitors torque values and ensures torque remains above a predetermined positive threshold, preventing the drive system from entering the backlash region where torque approaches zero or becomes negative. This proactive approach eliminates backlash before it can occur rather than reacting after it happens.
Solution Approach 2:
The invention applies parameter changes by dynamically adjusting the torque command to maintain it above a predetermined positive threshold value. When the torque command approaches the backlash region (near zero or negative values), the controller modifies the torque parameter to stay within the safe operating range, thus preventing backlash while allowing rapid torque changes for responsive acceleration.
2Object-affected harmful factors
If torque change rate is reduced to prevent backlash, then NVH is improved, but acceleration responsiveness deteriorates
Solution Approach 1:
The control method performs preliminary action by maintaining a minimum positive torque threshold before backlash occurs. The controller continuously monitors torque values and ensures torque remains above a predetermined positive threshold, preventing the drive system from entering the backlash region where torque approaches zero or becomes negative. This proactive approach eliminates backlash before it can occur rather than reacting after it happens.
Solution Approach 2:
The invention applies parameter changes by dynamically adjusting the torque command to maintain it above a predetermined positive threshold value. When the torque command approaches the backlash region (near zero or negative values), the controller modifies the torque parameter to stay within the safe operating range, thus preventing backlash while allowing rapid torque changes for responsive acceleration.
3Object-affected harmful factors
If conventional backlash compensation control is applied, then NVH is reduced, but vehicle responsiveness deteriorates due to chronic torque changes
Solution Approach 1:
The control method performs preliminary action by maintaining a minimum positive torque threshold before backlash occurs. The controller continuously monitors torque values and ensures torque remains above a predetermined positive threshold, preventing the drive system from entering the backlash region where torque approaches zero or becomes negative. This proactive approach eliminates backlash before it can occur rather than reacting after it happens.
Solution Approach 2:
The invention applies parameter changes by dynamically adjusting the torque command to maintain it above a predetermined positive threshold value. When the torque command approaches the backlash region (near zero or negative values), the controller modifies the torque parameter to stay within the safe operating range, thus preventing backlash while allowing rapid torque changes for responsive acceleration.
Data Source
AI summary
A method of controlling torque of a drive system of an electric vehicle includes determining, by a controller, required torque according to a vehicle driving state while the vehicle is driven, and determining a total torque command based on the determined required torque, and performing, by the controller, a front wheel and rear wheel torque distribution process on the total torque command, so that a front wheel torque command and a rear wheel torque command following the total torque command are determined.