Motor Controller Current Transition to Reduce EV Charging NVH

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Solution Overview

Problem

The rapid reduction of motor winding current when a charging pile stops supplying power leads to poor noise, vibration, and harshness (NVH) features in electric vehicles due to mechanical structure slipping and rebounding.

Innovation Solution

A powertrain with a motor controller that gradually decreases motor current by switching from direct current power supply to power battery supply, using three bridge arms with switching transistors to control the current flow, thereby reducing torque release and slipping sound.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the charging pile stops supplying power actively, then the charging process can be ended, but the motor winding current reduces rapidly causing poor NVH features

Engineering Contradiction:

Improvecharging efficiencyVSAvoidNVH (noise, vibration, harshness)

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a motor controller as an intermediary device between the charging pile and the motor winding. This controller actively manages the current flow during charging termination, transitioning from direct charging pile power supply to controlled motor controller power supply. This intermediary mechanism allows gradual current reduction rather than abrupt interruption, thereby resolving the NVH issue while maintaining charging functionality.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent implements dynamic control of the motor winding current during the charging termination process. The motor controller dynamically adjusts the current magnitude and timing, switching between different power supply modes (charging pile direct supply vs. motor controller supply) based on real-time conditions. This dynamic approach enables smooth current transition that prevents mechanical structure slipping and rebound, improving NVH performance.

Inventive Principle:

Principle #15Dynamics

2Loss of time

If the motor winding current is reduced rapidly when charging stops, then the charging process ends quickly, but torque release reduces rapidly to zero causing mechanical structure slipping and rebound

Engineering Contradiction:

Improvecharging termination timeVSAvoidmechanical structure stability

Core Design Contradiction:

Loss of timeVSStability of the object's composition

Solution Approach 1:

The patent applies preliminary action by having the motor controller prepare and manage the current transition before the charging pile fully disconnects. The controller anticipates the charging termination and begins managing current flow in advance, ensuring a controlled transition that maintains torque and prevents mechanical instability. This preliminary management of current flow avoids abrupt changes that would cause slipping and rebound.

Inventive Principle:

Principle #10Preliminary action

3Adaptability or versatility

If a power supply circuit reuses motor winding to boost voltage from charging pile, then voltage matching between 220-500V charging pile and 600-800V power battery is achieved, but NVH performance deteriorates when power supply stops

Engineering Contradiction:

Improvevoltage adaptabilityVSAvoidNVH (noise, vibration, harshness)

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent implements multi-functionality by enabling the motor controller to serve multiple purposes: during charging, it manages power flow and voltage boosting; during charging termination, it controls current reduction to maintain NVH performance. This universal control mechanism handles both voltage adaptation and NVH management within a single integrated system, resolving the contradiction between voltage adaptability and NVH performance.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

This solution effectively improves the NVH performance of electric vehicles by slowing down the current decrease and maintaining torque, reducing mechanical structure slipping and noise.

Implementation Method 1

Methodology Applied

Scientific EffectElectrical switching:

Data Source

PatentUS20250100393A1Powertrain, control method for motor controller, and electric vehicle

Publication Date: 2025.03.27 HUAWEI DIGITAL POWER TECH CO LTD

AI summary

This application provides a powertrain, a control method for a motor controller, and an electric vehicle. The powertrain includes a motor controller and a drive motor, the motor controller includes three bridge arms connected in parallel, and a bridge arm midpoint of one of the three bridge arms is configured to connect to the other end of the direct current power supply. In response to that the direct current power supply switches from outputting a direct current to stopping outputting the direct current, an upper bridge arm switching transistor of one bridge arm of the other two bridge arms of the three bridge arms is turned on and a lower bridge arm switching transistor of the other bridge arm of the other two bridge arms is turned on. The power battery is configured to supply power to one phase winding and another phase winding, to reduce slipping sound.