Rotary Electrical Machine Torque Oscillation Compensation

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Solution Overview

Problem

Torque oscillations in a motor vehicle's traction chain cause substantial shaking during electric travel due to the rigidity of the kinematic chain, particularly the drive shaft and universal joints, leading to discomfort for passengers.

Innovation Solution

A method for controlling a rotary electrical machine that involves generating a set point torque, determining a pulsed compensation torque to counteract these oscillations, combining it with the set point torque, and applying the resulting modified torque to the machine, using a pass-band filter and gain based on the speed signal and damping factor to adjust the compensation precisely.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the thermal engine is switched off and the clutch is opened during electric travel, then energy efficiency is improved and emissions are reduced, but torque oscillations and vehicle shaking increase due to the rigidity of the kinematic chain

Engineering Contradiction:

Improveenergy efficiencyVSAvoidtorque oscillations

Core Design Contradiction:

Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The control method applies a compensating pulsed torque in advance to counteract the anticipated torque oscillations. The controller generates a compensation torque signal that is added to the setpoint torque, creating a preliminary counter-action that prevents the oscillations from propagating through the rigid kinematic chain during electric travel modes.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The invention utilizes periodic pulsed torque compensation that matches the frequency of the natural oscillations in the drivetrain. By applying compensating torque pulses at the resonant frequency of the mass-spring system (drive shaft and universal joints), the system effectively dampens the oscillations without requiring continuous thermal engine operation.

Inventive Principle:

Principle #19Periodic action

2Object-affected harmful factors

If the clutch remains engaged to provide natural damping, then torque oscillations are reduced, but the ability to operate in pure electric mode is compromised

Engineering Contradiction:

Improvetorque oscillationsVSAvoidelectric mode operation

Core Design Contradiction:

Object-affected harmful factorsVSAdaptability or versatility

Solution Approach 1:

The invention replaces the mechanical damping function of the engaged clutch with an electronic control system. The controller substitutes the physical connection and friction-based damping of the thermal engine with an electronically generated compensating torque signal, allowing the clutch to remain disengaged while achieving similar vibration suppression效果.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The control system acts as an intermediary between the electrical machine and the drivetrain, inserting a virtual damping element through software control. The controller processes speed signals, determines compensation torque based on detected oscillations, and injects counter-torque commands to the electrical machine, effectively mediating the interaction between the electric motor and the rigid kinematic chain.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Power

If a rigid kinematic chain is used for efficient power transmission, then mechanical efficiency is improved, but resonance frequency issues and vehicle shaking increase

Engineering Contradiction:

Improvemechanical efficiencyVSAvoidresonance frequency

Core Design Contradiction:

PowerVSStability of the object's composition

Solution Approach 1:

The invention introduces dynamic control to the previously static rigid kinematic chain. By continuously monitoring the speed signal and adjusting the compensating torque in real-time based on detected oscillations, the system transforms the rigid mechanical system into a dynamically controlled system that can adapt to varying resonance conditions across different operating speeds and gear ratios.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The control method changes the effective parameters of the kinematic chain by superimposing compensating torque that alters the dynamic characteristics of the system. The compensation modifies the effective stiffness and damping parameters of the drive train, allowing the rigid chain to operate efficiently while suppressing resonance at critical speeds and gear transitions.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS11654776B2Method for controlling a rotary electrical machine in order to compensate for the torque oscillations of a traction chain of a motor vehicle

Publication Date: 2023.05.23 VALEO EQUIP ELECTRIC MOTEUR

AI summary

A method for controlling a rotating electrical machine of a motor vehicle is disclosed. The motor vehicle includes a thermal drive chain including a heat engine connected to a gearbox by means of a clutch. The electrical machine is integrated in the thermal drive chain or in a drive chain independent of the heat engine. When the clutch is open and the rotating electrical machine operates in motor mode in order to ensure the electrical operation of the motor vehicle, the method includes: generating a setpoint torque corresponding to a desire of the driver to accelerate; determining a pulsed compensation torque for torque oscillations generated by the drive chain; combining the setpoint torque and the previously determined pulsed compensation torque in order to obtain a resulting modified setpoint torque; and applying the resulting modified setpoint torque to the rotating electrical machine.