Drive Motor Torque Control for Tip-in Shock Reduction
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Solution Overview
Problem
Electric and fuel cell vehicles experience shocks and noise during tip-in and tip-out due to motor torque changes, particularly at low speeds, which affect ride comfort and require effective torque control solutions.
Innovation Solution
A torque control apparatus and method for a drive motor that determines whether an input torque is rising or falling, selects and adjusts torque rates using specific rate maps based on shift modes, and adjusts the torque rates to reduce shock and noise by employing a controller with limiter and supply sections to manage torque changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If motor torque is changed rapidly during tip-in or tip-out, then motor response speed is improved, but shock and noise increase affecting ride comfort
Solution Approach 1:
The patent applies dynamics by making the torque change rate adaptive rather than fixed. The controller dynamically adjusts the torque change rate based on real-time operating conditions (vehicle speed, acceleration request, regenerative braking status) to balance response speed and ride comfort. This is achieved through continuous monitoring and adjustment of the torque command signal during tip-in and tip-out transitions.
Solution Approach 2:
The patent changes the parameter of torque change rate based on different operating conditions. By modifying the torque change rate parameter according to vehicle speed, acceleration requests, and regenerative braking status, the system optimizes both response speed and comfort. Different torque change rates are applied in different operational scenarios to prevent shock and noise while maintaining adequate responsiveness.
2Loss of energy
If regenerative braking is applied during tip-in at low speed, then energy recovery is improved, but shock and noise increase
Solution Approach 1:
The patent uses feedback by continuously monitoring vehicle speed, acceleration requests, and regenerative braking status to determine when to apply or limit regenerative braking. The controller adjusts the torque change rate based on feedback from these sensors, reducing the torque change rate when regenerative braking is active at low speeds to minimize shock and noise while still enabling energy recovery.
3Object-affected harmful factors
If different torque rate maps are applied to tip-in and tip-out, then ride comfort is improved, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the torque control into separate maps for tip-in and tip-out operations. Each map contains optimized torque change rates for specific scenarios (acceleration, deceleration, regenerative braking). This segmentation allows tailored control strategies for different operational modes, improving ride comfort while keeping each map relatively simple and manageable.
Data Source
AI summary
A torque control apparatus and method for a drive motor is provided. The torque control method includes determining whether an input request torque is a rising torque or a falling torque. In addition, a controller is configured to select one of a rising rate map and a falling rate map based on a result of the judgment on the input request torque. Further, the controller is configured to adjust a rising rate of the rising torque using the rising rate map or a falling rate of the falling torque using the falling rate map.