Regenerative Braking Control for Powertrain Oscillation Mitigation

Solution Overview

Problem

Electric vehicles experience powertrain oscillations during regenerative braking, leading to unpleasant noise and potential damage, as existing systems often react after oscillations occur rather than proactively mitigating them.

Innovation Solution

A vehicle system that includes a controller capable of predicting future powertrain oscillations based on wheel speed and total brake torque inputs, which reduces regenerative brake torque prior to oscillation events to prevent damage and improve efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If regenerative braking is applied during vehicle operation, then energy recovery and fuel economy are improved, but powertrain oscillations occur causing noise and potential damage

Engineering Contradiction:

Improveenergy recoveryVSAvoidpowertrain oscillation

Core Design Contradiction:

Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The controller performs preliminary action by predicting future powertrain oscillation events based on current wheel speed and brake torque inputs before they actually occur. The system calculates predicted oscillation magnitude and timing, then proactively reduces regenerative brake torque in advance of the predicted oscillation event, preventing the harmful oscillations before they can damage the powertrain while still maintaining energy recovery during normal operation

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements feedback by continuously monitoring wheel speed and brake torque inputs, using this feedback to update predictions of future powertrain oscillation events. The controller adjusts regenerative brake torque based on this feedback loop, reducing torque when oscillation is predicted and maintaining or increasing torque when oscillation is not anticipated, thereby optimizing both energy recovery and powertrain protection

Inventive Principle:

Principle #23Feedback

2Reliability

If regenerative brake torque is reduced to prevent powertrain oscillation, then powertrain damage is mitigated, but energy recovery efficiency decreases

Engineering Contradiction:

Improvepowertrain durabilityVSAvoidenergy recovery efficiency

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The controller performs preliminary action by predicting future powertrain oscillation events based on current wheel speed and brake torque inputs before they actually occur. The system calculates predicted oscillation magnitude and timing, then proactively reduces regenerative brake torque in advance of the predicted oscillation event, preventing the harmful oscillations before they can damage the powertrain while still maintaining energy recovery during normal operation

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system applies dynamics by continuously adjusting regenerative brake torque in real-time based on predicted oscillation conditions. The controller dynamically modulates the regenerative brake torque command, increasing it when oscillation is not predicted to maximize energy recovery, and reducing it when oscillation is anticipated to protect the powertrain, thereby optimizing the balance between energy recovery efficiency and powertrain durability

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS8712616B2Regenerative braking control to mitigate powertrain oscillation

Publication Date: 2014.04.29 FORD GLOBAL TECH LLC

AI summary

A vehicle is provided with at least one wheel and a motor that is coupled to the wheel. The motor is configured to provide regenerative brake torque. The vehicle also includes at least one controller that is configured to predict future powertrain oscillation based on input indicative of a wheel speed and a total brake torque. The controller is also configured to control the motor to reduce the regenerative brake torque prior to the powertrain oscillation.