EV Control Device Regenerative Braking Vibration Suppression
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Solution Overview
Problem
Electric motor vehicles experience vibration in the front-back direction when decelerated using regenerative braking force, especially when the vehicle comes to a stop, due to the inability to effectively manage regenerative braking force.
Innovation Solution
A control device for electric motor vehicles that detects the accelerator operation amount, calculates a motor torque command value, and adjusts feedback torque based on a disturbance torque estimate to converge the motor torque command value to the disturbance torque when the vehicle stops, using a combination of feedback and feedforward torque control to manage regenerative braking force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If regenerative braking force is increased to improve deceleration performance, then deceleration capability is improved, but vehicle body vibration occurs when the vehicle stops
Solution Approach 1:
The control device dynamically adjusts the regenerative braking force based on real-time vehicle speed and acceleration information. As the vehicle approaches stop, the control system modifies the braking force magnitude to prevent vibration, while maintaining effective deceleration at higher speeds. This dynamic adjustment resolves the contradiction between deceleration performance and vibration suppression.
Solution Approach 2:
The control device uses feedback from speed and acceleration sensors to continuously monitor vehicle state during deceleration. When the vehicle approaches stop, the feedback signal triggers adjustment of the regenerative braking force to eliminate vibration. This closed-loop control ensures both effective deceleration and vibration-free stopping.
2Object-affected harmful factors
If regenerative braking force is reduced to suppress vibration, then vehicle body vibration is suppressed, but deceleration performance deteriorates
Solution Approach 1:
The control device dynamically adjusts the regenerative braking force based on real-time vehicle speed and acceleration information. As the vehicle approaches stop, the control system modifies the braking force magnitude to prevent vibration, while maintaining effective deceleration at higher speeds. This dynamic adjustment resolves the contradiction between deceleration performance and vibration suppression.
Solution Approach 2:
The control device uses feedback from speed and acceleration sensors to continuously monitor vehicle state during deceleration. When the vehicle approaches stop, the feedback signal triggers adjustment of the regenerative braking force to eliminate vibration. This closed-loop control ensures both effective deceleration and vibration-free stopping.
3Measurement precision
If feedback torque is increased to improve stopping control, then stopping precision is improved, but system complexity increases due to disturbance torque estimation
Solution Approach 1:
The control device uses the vehicle's existing sensors (speed and acceleration sensors) to estimate disturbance torque, rather than requiring additional dedicated sensors. The system leverages available data to calculate feedback torque, achieving precise stopping control without significantly increasing system complexity. This self-service approach uses existing resources to solve the control precision problem.
Data Source
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AI summary
A control device for electric motor vehicle uses a motor as a traveling drive source and is configured to decelerate by a regenerative braking force of the motor when an accelerator operation amount decreases or becomes zero. The control device detects the accelerator operation amount, calculates a motor torque command value, and controls the motor on the basis of the motor torque command value calculated. The control device detects a speed parameter proportional to a traveling speed of the electric motor vehicle and calculates a feedback torque for stopping the electric motor vehicle on the basis of the speed parameter detected. The control device also estimates a disturbance torque acting on the motor and converges, as the speed parameter is reduced, the motor torque command value to the disturbance torque on the basis of the feedback torque when the accelerator operation amount decreases or becomes zero and the electric motor vehicle stops shortly. The control device furthermore adjusts the feedback torque according to the disturbance torque.