Electric Vehicle Torque Controller Vibration Damping
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Solution Overview
Problem
Existing electric vehicle controllers face challenges in preventing torque vibration while achieving vibration damping, particularly when the vehicle's transmission characteristic deviates from its identification model, leading to resonant vibrations in the output torque.
Innovation Solution
A controller for electric vehicles that employs a band pass filter characteristic in both torque command value and motor revolution speed filtering treatments, using an attenuation coefficient larger than the identification value of the transmission characteristic model to calculate a torque command value, thereby suppressing torque vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a filter with transmission characteristic H(s)/Gp(s) is used to calculate torque command value, then vibration damping effect is achieved, but torque vibration occurs when vehicle transmission characteristic deviates from identification model Gp(s)
Solution Approach 1:
The patent changes the parameter of the filter's transmission characteristic from H(s)/Gp(s) to H(s)/Gz(s), where Gz(s) is a modified model with adjusted attenuation coefficient. This parameter change allows the filter to maintain vibration damping effectiveness while preventing torque vibration caused by model deviation, as the modified transmission characteristic better matches the actual vehicle dynamics.
2Measurement precision
If the attenuation coefficient in the filter model is set to match the identification value, then the filter accurately represents the system, but torque vibration occurs due to phase and gain differences when the actual transmission characteristic deviates from the model
Solution Approach 1:
The patent applies beforehand cushioning by pre-modifying the filter model's attenuation coefficient to anticipate and compensate for potential deviations between the identification model and actual vehicle transmission characteristics. This proactive adjustment prevents torque vibration before it occurs, rather than reacting to model mismatches after they cause problems.
Solution Approach 2:
The patent modifies the attenuation coefficient parameter in the filter model to create a more robust transmission characteristic that accounts for real-world variations. By adjusting this key parameter, the filter maintains stability and prevents torque vibration while still providing effective vibration damping across different operating conditions.
Data Source
AI summary
A controller of electric vehicle includes: sensor sensing vehicle information; torque target value setter; torque command value calculator; first paragraph calculator implementing first filtering treatment of the torque command value, the first filtering treatment including transmission characteristic having hand pass filter characteristic; second paragraph calculator implementing second filtering treatment of motor revolution speed which is one of pieces of the vehicle information, the second filtering treatment including: the transmission characteristic having band pass filter characteristic, and model of a transmission characteristic between: torque input to the vehicle, and the motor revolution speed; torque target value calculator calculating the second torque target value. Based on the first torque target value and the second torque target value, the torque command value calculator calculates the torque command value. In the second filtering treatment, the second paragraph calculator uses attenuation coefficient which is larger than identification value of the model of the transmission characteristic.