Motor Peak Performance Testing Under High-Speed Skin Effect

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Solution Overview

Problem

Existing methods for testing motor performance in new energy vehicles do not adequately consider the skin effect at high speeds, leading to uneven current density and higher temperature rises in stator slots, which affects the maintenance of maximum copper loss density.

Innovation Solution

A method and device that adjust the maximum allowable power supply current when the motor reaches a predetermined rotational speed, accounting for the skin effect to maintain constant copper loss density by decreasing current with increasing speed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If rectangular flat wires are used in the motor, then slot fill rate and quality control are improved, but skin effect at high speeds causes uneven current density and higher temperature rise

Engineering Contradiction:
Improveslot fill rateVSAvoidskin effect
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent adjusts the maximum allowable power supply current as a variable parameter based on rotational speed. At low speeds, higher current is permitted; at high speeds, current is reduced to compensate for skin effect, maintaining constant copper loss density throughout the operating range.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If traditional performance testing methods are used considering only voltage and current limitations, then testing simplicity is maintained, but peak performance cannot be accurately determined due to unaccounted temperature rise at high speeds

Engineering Contradiction:
Improvetesting method complexityVSAvoidpeak performance measurement
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent transforms the static current limit into a dynamic parameter that varies with rotational speed. The testing method dynamically adjusts the maximum allowable current based on the motor's operating speed, enabling accurate peak performance measurement across the entire speed range while maintaining test feasibility.

Inventive Principle:
Principle #15Dynamics

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

The method and device ensure that the maximum copper loss density remains constant with increasing rotational speed, addressing the skin effect and providing accurate peak performance testing beyond traditional voltage and current limitations.

Implementation Method 1

since the rectangular flat wires have a strong skin effect at high speeds, the current density in conductors in a stator slot is severely uneven, which will lead to a higher temperature rise of the motor at high speeds

Methodology Applied
Scientific EffectSkin effect: Skin Effect

Data Source

PatentEP4339631B1Method and device for testing peak performance of motor
Publication Date: 2026.01.21 SCHAEFFLER TECHNOLOGIES AG & CO KG
  • EP4339631B1 patent drawingFigure 1
  • EP4339631B1 patent drawingFigure 2
  • EP4339631B1 patent drawingFigure 3

AI summary

The present invention provides a method and device for testing the peak performance of a motor. The method comprises: a test step of setting a maximum allowable power supply current of the motor, and testing the peak performance of the motor by using the set maximum allowable power supply current; an adjustment step of adjusting the set maximum allowable power supply current when the rotational speed of the motor reaches a predetermined rotational speed in the process of testing the performance of the motor according to the set maximum allowable power supply current, such that the current decreases with the increase of the rotational speed of the motor; and a test step of continuing to test the peak performance of the motor by using the adjusted maximum allowable power supply current. Hence, maximum copper loss density can be maintained substantially constant with the increase of the rotational speed of the motor.