Electric Vehicle Damping Control via Resonance Frequency Filtering
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Solution Overview
Problem
Existing damping control devices for electric vehicles with transmission systems in the drive system between a motor and a drive wheel face practicality issues due to changing resonance frequencies with varying transmission gear ratios, particularly when a motor with small mass is coupled to the system, leading to difficulties in absorbing resonance and affecting riding comfort.
Innovation Solution
A damping control device that includes a detector, bandpass filter, and calculators to detect and calculate a damping torque for the drive system, using a bandpass filter to extract vibration components at resonance frequencies and calculate a target damping torque by subtracting an offset value from the calculated damping torque, which is then added to the motor torque to control the motor's drive state and reduce resonance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a motor with small mass is coupled to the drive system, then the device complexity is reduced, but the resonance absorption capability deteriorates
Solution Approach 1:
The patent replaces the mechanical resonance absorption capability (which depends on motor mass) with a control system that uses sensors, processors, and actuators to detect and counteract resonance vibrations through active control, thereby maintaining small motor mass while achieving effective resonance suppression
Solution Approach 2:
The patent implements a feedback control mechanism where sensors detect vibration components at resonance frequencies, the processor calculates the detected resonance, and the system applies counteracting torque to the motor shaft to actively suppress resonance, enabling effective resonance absorption without increasing motor mass
2Object-affected harmful factors
If damping control is applied to reduce resonance, then riding comfort is improved, but acceleration and deceleration performance may be affected
Solution Approach 1:
The patent applies damping control selectively only to the resonance frequency components detected by the bandpass filter, while leaving other frequency components (including those related to acceleration and deceleration) unaffected, thereby improving riding comfort without compromising acceleration and deceleration performance
Solution Approach 2:
The patent uses vibration detection and analysis to identify resonance frequency components, then applies targeted damping control at these specific frequencies while maintaining normal motor operation at other frequencies, achieving localized resonance suppression that preserves overall vehicle performance
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution effectively reduces resonance in the drive system without preventing acceleration and deceleration, improving riding comfort by damping the resonance frequency without the need for multiple plant models for different transmission gear ratios, and is applicable to vehicles with both engines and fuel cells.
Implementation Method 1
resonance occurs due to elasticity (torsion) of a drive system between the motor and the drive wheel
Implementation Method 2
a bandpass filter configured to pass a vibration component in a resonance frequency band of the drive system
Implementation Method 3
calculate a damping torque for damping resonance of the drive system with a motor torque
Data Source
AI summary
A damping control device for an electric vehicle including a motor and a transmission in a drive system between the motor and a drive wheel includes a detector, a bandpass filter, first to third calculators, and a controller. The detector detects a rotation speed of the motor. The bandpass filter passes a vibration component included in the detected motor rotation speed, in a resonance frequency band of the drive system. The first calculator calculates a damping torque for damping resonance of the drive system with a motor torque, based on the passed vibration component. The second calculator calculates, as a damping torque offset value, an average value of the calculated damping torque for a predetermined time. The third calculator calculates a target damping torque. The controller controls a drive state of the motor.