Electric Motor Torque Correction for Drive Train Oscillation Damping
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Solution Overview
Problem
Electric vehicles experience pronounced drive train oscillations, particularly during starting, due to irregular torque from the electric motor, rotational speed sensor, and closed-loop control effects, leading to juddering and resonance, which conventional methods fail to adequately address without compromising vehicle acceleration or driver response.
Innovation Solution
A method involving a closed-loop control system that calculates a correction torque for the electric motor setpoint torque based on the current rotational speed, using a bandpass filter to extract the rotational speed interference signal and a three-point closed-loop controller to determine a correction factor, allowing for electronic damping of oscillations without mechanical intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If mechanical damping or decoupling via clutch is used to prevent drive train oscillations, then oscillation damping is improved, but device complexity and response time worsen
Solution Approach 1:
The patent replaces mechanical damping systems (clutches, mechanical decoupling devices) with an electronic control system that calculates a corrected setpoint torque for the electric motor. This electronic torque correction compensates for oscillations without requiring additional mechanical damping components, thus reducing device complexity while maintaining oscillation damping effectiveness.
Solution Approach 2:
The patent implements a feedback control mechanism where the actual motor torque and rotational speed are continuously monitored, oscillation components are detected, and a correction torque is calculated and applied in real-time. This closed-loop feedback system enables active oscillation compensation without mechanical damping devices.
2Stability of the object's composition
If strong limitation of torque gradients is applied to reduce excitation of the spring system, then oscillation damping is improved, but productivity and response behavior worsen
Solution Approach 1:
The patent dynamically adjusts the setpoint torque parameters of the electric motor based on detected oscillation conditions. Instead of applying strong limitation to all torque gradients, the system selectively modifies torque commands only when oscillations are detected, preserving acceleration performance while damping oscillations. The correction torque is calculated as a function of the difference between actual and desired torque, allowing adaptive parameter adjustment.
Solution Approach 2:
The patent implements a dynamic torque correction system that adapts to changing driving conditions. The correction factor is calculated based on real-time oscillation detection and varies with operating conditions, allowing the system to provide strong damping when needed while maintaining full acceleration capability during normal operation. This dynamic approach avoids the performance penalties of static torque limitation.
Data Source
AI summary
A method for damping juddering in the drive train of a vehicle having an electric motor as the drive motor, and a vehicle having a closed-loop control system to carry out the method. The method includes calculating an electric motor setpoint torque for actuating the electric motor from an electric motor request torque which corresponds to a current request for a torque, and calculating a correction torque as a function of the electric motor request torque and a correction factor which is determined from a rotational speed of the electric motor.