Torque Control System for Electric Vehicle Vibration Suppression
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Solution Overview
Problem
Existing control systems for electric vehicles require high torque control performance to effectively suppress undesired vibration caused by disturbance torque, which is not achieved at low speed low torque conditions due to low controllability of the inverter.
Innovation Solution
A control system that adjusts the reference torque based on vehicle speed, using a vehicle speed calculation section and a control unit with a reference torque correction section to change the torque when the vehicle is in a given speed range, thereby reducing the time spent in resonance induction speed ranges and minimizing vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If high torque control performance is used to suppress disturbance torque, then vibration restraining effect is improved, but torque control performance becomes difficult to achieve at low speed low torque conditions
Solution Approach 1:
The patent changes the reference torque parameter dynamically based on vehicle speed. When the vehicle speed enters a predetermined speed range that induces resonant vibration, the reference torque is decreased or increased and then returned to its original level, thereby changing the torque parameter to avoid the resonance condition and suppress vibration without requiring high torque control performance
Solution Approach 2:
The control system predicts the entry into resonance induction speed ranges and takes preliminary action by adjusting the reference torque before the vibration occurs. The vehicle speed is continuously monitored, and when it approaches the problematic speed range, the reference torque is modified in advance to prevent resonant vibration from occurring
2Object-affected harmful factors
If reference torque is adjusted to avoid resonance induction speed ranges, then vibration suppression is improved, but system complexity increases
Solution Approach 1:
The patent uses pre-defined maps that store the relationship between vehicle speed and corrected torque values. Instead of implementing complex real-time calculations, the system copies proven torque correction strategies from pre-calculated maps, simplifying the control logic while maintaining effective vibration suppression
Solution Approach 2:
The patent introduces a vehicle speed calculation section as an intermediary that continuously monitors speed and triggers reference torque correction only when the speed enters the predetermined range. This intermediary mechanism simplifies the control flow by acting as a gatekeeper that activates torque correction only when necessary, rather than continuously adjusting torque based on complex vibration sensors
Data Source
AI summary
A control system for an electric vehicle has a vehicle speed calculation section that calculates a speed of the electric vehicle and a control unit that controls an inverter of an electric motor to provide road wheels with a predetermined reference torque in accordance with a manipulated value of an accelerator pedal, wherein the unit has a reference torque correction section that changes the reference torque from an original value and then returns the changed reference torque to the original value when a calculated speed of the electric vehicle is in a given speed range.