Motor Torque Control Apparatus for Electric Vehicle Tip-In Jolting
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Solution Overview
Problem
Electric and fuel cell vehicles experience jolting and noise during acceleration or tip-in operations, particularly at low speeds, which degrade ride comfort and require a motor torque control solution to mitigate these issues.
Innovation Solution
A motor torque control apparatus and method that includes a limiter, L-mode and D-mode control units, and a switch unit to selectively apply slew rate variable maps, limiting the torque increase rate and feeding back the intermediate torque signal to adjust the slew rate, thereby reducing jolting and noise during tip-in operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the motor torque is rapidly increased during tip-in operation to improve acceleration response, then the acceleration response is improved, but jolting and noise occur degrading ride comfort
Solution Approach 1:
The patent applies preliminary action by pre-defining multiple slew rate variable maps (first through fourth maps) corresponding to different vehicle speed ranges and operation modes. These maps are prepared in advance and selected based on the current vehicle state, allowing the torque signal to be smoothly limited without real-time complex calculations, thus improving acceleration response while preventing jolting and noise through pre-planned torque increase rate limitations.
Solution Approach 2:
The patent implements dynamics by making the slew rate limit variable rather than fixed. The system dynamically selects different slew rate variable maps based on vehicle speed ranges and operation modes (regenerative braking vs. non-regenerative braking). This dynamic adaptation allows the torque increase rate to be optimized for each operating condition, achieving both fast response and comfort across different driving scenarios.
2Object-affected harmful factors
If the slew rate is strictly limited to reduce jolting and noise, then ride comfort is improved, but the response to acceleration is degraded
Solution Approach 1:
The patent applies parameter changes by varying the slew rate limit parameters according to different vehicle operating conditions. Instead of using a single fixed slew rate limit, the system changes the limit parameters by selecting from multiple pre-defined slew rate variable maps that correspond to different vehicle speed ranges and operation modes. This allows the torque increase rate to be appropriately adjusted for each condition, achieving both comfort and response performance.
Solution Approach 2:
The system dynamically adjusts the slew rate limit based on real-time vehicle state detection. By monitoring vehicle speed and operation mode, the system dynamically selects the most appropriate slew rate variable map, making the torque limitation adaptive rather than static. This dynamic approach ensures that the torque increase rate is optimized for each specific operating condition.
3Device complexity
If a single slew rate map is used for all operation modes, then the control system is simple, but the torque control is not optimized for different operation modes causing suboptimal performance
Solution Approach 1:
The patent applies segmentation by dividing the torque control system into multiple segments corresponding to different operation modes and vehicle speed ranges. Instead of using a single unified slew rate map, the system segments the control space into four distinct slew rate variable maps, each optimized for specific operating conditions. This segmentation allows each map to be relatively simple while collectively providing optimized control across all operating modes.
Solution Approach 2:
The patent implements universality by designing a multi-functional slew rate selection mechanism that can adapt to different operation modes (regenerative braking and non-regenerative braking) and vehicle speed ranges. The switch unit and determination unit work together to make the control system universal, capable of handling multiple operating scenarios with a unified architecture that selects from pre-optimized maps, achieving both simplicity and performance.
Data Source
AI summary
A motor torque control apparatus and method are provided for reducing jolting and noise caused by an acceleration or tip-in operation in an electric or fuel cell vehicle and for improving response to acceleration by the acceleration or tip-in operation. The motor torque control apparatus includes a limiter operative to limit a slew rate of a final torque signal applied to a motor of the vehicle based on a maximum slew rate selected from one of two previously-input slew rate variable maps. Specifically, L-mode and D-mode control units select the slew rate according to slew rate variable maps of an L mode and of D mode, respectively. A switch unit connects one of the L-mode and D-mode control units to the limiter based on a current operation state of the vehicle. The control units select the slew rate based on the torque signal output by the limiter.