Electric Motor Deceleration Control for Reliable Regenerative Braking

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Solution Overview

Problem

Friction brakes in motor vehicles contribute significantly to the vehicle's mass and require large installation space, and their deceleration process results in energy loss and environmental pollution, while existing electromotive deceleration methods lack reliability due to component failures.

Innovation Solution

A method for controlling an electromotive drive that uses an electric motor to convert rotational energy into electrical energy with varying efficiencies, allowing for reliable deceleration torque generation without relying on battery capacity, and dissipating excess energy as heat when necessary.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If friction brakes are used for deceleration, then reliable deceleration is achieved, but vehicle mass increases and installation space is required

Engineering Contradiction:

Improvedeceleration reliabilityVSAvoidbrake mass

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The patent combines the friction brake system with the electromotive drive system into an integrated deceleration system. The controller coordinates both the friction brake and the electric motor (operating in generator mode) to work together for vehicle deceleration, allowing the friction brake to be downsized while maintaining overall deceleration reliability through the combined effect of both systems.

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If friction brakes are used for deceleration, then deceleration function is provided, but energy is lost as heat and environmental pollution occurs

Engineering Contradiction:

Improvedeceleration functionVSAvoidenergy dissipation

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent converts the previously harmful effect of energy dissipation in friction brakes into a beneficial effect by using the electric motor as a generator during deceleration. The kinetic energy that would have been wasted as heat is instead converted into electrical energy that can be stored in the battery, transforming energy loss into energy recovery while the friction brake handles only the remaining deceleration requirement.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Loss of energy

If electromotive drive is used for deceleration with energy recuperation, then energy recovery is achieved, but reliability decreases due to component failures

Engineering Contradiction:

Improveenergy recoveryVSAvoiddeceleration reliability

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The patent prepares for potential failures of the electromotive drive components by maintaining the friction brake system as a backup deceleration mechanism. The controller is designed to automatically switch to or supplement friction brake usage if the electric motor or battery system fails, ensuring that deceleration reliability is maintained regardless of the status of the energy recuperation system.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

4Loss of energy

If battery capacity is increased for better energy recuperation, then energy recovery improves, but vehicle mass increases

Engineering Contradiction:

Improveenergy recuperation capacityVSAvoidbattery mass

Core Design Contradiction:

Loss of energyVSWeight of moving object

Solution Approach 1:

The patent applies partial action by using the friction brake system to handle a portion of the deceleration task, thereby reducing the energy recuperation demand on the battery. This allows the battery to be sized for moderate energy recovery capacity rather than requiring large capacity to handle all deceleration energy, reducing battery mass while still achieving meaningful energy recovery.

Inventive Principle:

Principle #16Partial or excessive action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables reliable deceleration torque provision, reduces brake size and weight, and recovers energy efficiently, minimizing environmental impact by utilizing the electric motor's cooling system to dissipate excess energy.

Implementation Method 1

the electric motor is actuated such that the rotational energy of the vehicle wheel is converted into electrical energy

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a large portion of the rotational energy is to be converted into heat which accumulates in the electric motor and its peripherals

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Data Source

PatentUS12502982B2Method for controlling an electromotive drive of a motor vehicle

Publication Date: 2025.12.23 CONTINENTAL AUTOMOTIVE TECHNOLOGIES GMBH

AI summary

A method for controlling an electromotive drive of a motor vehicle. At least one of the motor vehicle wheels can be driven by an electric motor of the electromotive drive and the electromotive drive has at least one energy source for the electric motor. The method includes: identifying a request for applying a deceleration torque to the vehicle wheel, identifying status of the electromotive drive, selecting an operating mode of the electric motor according to the identified status, and controlling the electric motor in the selected operating mode for applying the deceleration torque. In a first operating mode, the electric motor is controlled such that the rotational energy of the vehicle wheel is converted at a first efficiency into electrical energy. In a second operating mode, the electric motor is controlled such that the rotational energy of the vehicle wheel is converted at a second efficiency into electrical energy.