Electric Motor Shut-off Path Verification Without Mechanical Spinning

Solution Overview

Problem

In hybrid electric vehicles, testing the effectiveness of electric traction motor shut-off paths is challenging, especially at vehicle startup, as spinning the motor for torque shutoff path checks can be impractical and cause audible noise.

Innovation Solution

A method involving injecting currents into a three-phase electric motor, applying short or open circuits, and calculating the rate of current decay to verify the shut-off path without physically spinning the motor, using a predefined sequence to test all three phases with a single test.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the motor is spun to test shut-off path effectiveness, then the shut-off path can be verified, but the test becomes time-consuming and generates audible noise

Engineering Contradiction:

Improveshut-off path verificationVSAvoidtest duration

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces the mechanical spinning method with an electrical testing method. Instead of physically rotating the motor to induce current for shut-off path verification, the system injects test currents directly into the motor windings and measures the decay characteristics. This electrical substitution eliminates the need for mechanical motion, thereby reducing test time and eliminating audible noise while maintaining verification reliability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent performs preliminary current injection and system configuration before the actual shut-off path measurement. The test current is pre-established in the motor windings, and the measurement system is prepared in advance. This preliminary setup allows the shut-off path to be verified by simply observing current decay after injection, rather than requiring time-consuming motor spinning and current induction procedures.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If the motor is spun to test shut-off path effectiveness, then the shut-off path can be verified, but audible noise is generated that concerns drivers

Engineering Contradiction:

Improveshut-off path verificationVSAvoidaudible noise

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the mechanical spinning method with an electrical testing method. Instead of physically rotating the motor to induce current for shut-off path verification, the system injects test currents directly into the motor windings and measures the decay characteristics. This electrical substitution eliminates the need for mechanical motion, thereby reducing test time and eliminating audible noise while maintaining verification reliability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If conventional shut-off path testing is performed at vehicle startup, then motor safety can be ensured, but the test may be impossible in some instances

Engineering Contradiction:

Improvemotor safety verificationVSAvoidtest applicability at startup

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent replaces the mechanical spinning method with an electrical testing method. Instead of physically rotating the motor to induce current for shut-off path verification, the system injects test currents directly into the motor windings and measures the decay characteristics. This electrical substitution eliminates the need for mechanical motion, thereby reducing test time and eliminating audible noise while maintaining verification reliability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent enables the motor control system to perform self-diagnosis at startup without requiring external testing equipment or motor spinning. The system uses its own power electronics to inject test currents and measure decay characteristics, allowing the motor to verify its own shut-off path functionality. This self-service capability ensures broad applicability across different vehicle startup conditions.

Inventive Principle:

Principle #25Self-service

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 effective verification of electric traction motor shut-off paths without motor spinning, reducing noise and improving efficiency in hybrid electric vehicle powertrains.

Implementation Method 1

The motor is spun and the current induced by the moving magnets or windings can be measured

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS7545111B2Testing inverter driven electric motor shut-off path

Publication Date: 2009.06.09 FCA US LLC

AI summary

A method for testing electric motor shut-off including injecting current into an electric motor, applying at least one of a short or an open to the electric motor for a predetermined length of time, calculating the rate of decay of the current and comparing rate of the decay with a predetermined decay criteria. In one implementation, a predefined sequence of opening and short circuiting the electric motor is used, and the shut-off path tests for the motor three phases can be verified with one test.