Electric Motor Control System Switching Multi-Pulse and One-Pulse Modes

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Solution Overview

Problem

Conventional electric vehicle control devices fail to adequately minimize motor noise and vibration while improving fuel efficiency.

Innovation Solution

A control system that switches between multi-pulse and one-pulse control modes based on electric power loss and noise of the electric motor, using a controller to determine the optimal control mode by referencing specific criteria related to rotation speed, voltage input, and torque command values, and acquires an electric current index to ensure the electric current does not exceed a threshold during switching.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If multi-pulse PWM control mode is used, then fuel efficiency is improved, but motor noise and vibration increase

Engineering Contradiction:

Improvefuel efficiencyVSAvoidmotor noise and vibration

Core Design Contradiction:

Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The control system dynamically switches between multi-pulse PWM control mode and synchronous single pulse control mode based on the inverter frequency. When the inverter frequency is within a specific frequency band that causes excessive noise and vibration, the system switches to synchronous single pulse control mode. When the frequency is outside this band, the system uses multi-pulse PWM control mode for better fuel efficiency. This dynamic adaptation resolves the contradiction by selecting the appropriate control mode according to operating conditions.

Inventive Principle:

Principle #15Dynamics

2Object-affected harmful factors

If synchronous single pulse control mode is used, then motor noise and vibration are reduced, but fuel efficiency deteriorates

Engineering Contradiction:

Improvemotor noise and vibrationVSAvoidfuel efficiency

Core Design Contradiction:

Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

Inventive Principle:

Principle #15Dynamics

3Use of energy by moving object

If control mode switching is implemented without considering electric current threshold, then fuel efficiency is improved, but motor durability decreases due to excessive current

Engineering Contradiction:

Improvefuel efficiencyVSAvoidmotor durability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The control system incorporates feedback mechanisms to monitor the inverter frequency and electric current output. The controller compares the inverter frequency with a predetermined frequency band and switches control modes accordingly. Additionally, the system monitors the electric current output and prevents switching to synchronous single pulse control mode when the current exceeds a predetermined threshold, thereby protecting motor durability while maintaining fuel efficiency benefits.

Inventive Principle:

Principle #23Feedback

4Device complexity

If control mode switching is implemented without electric current monitoring, then device complexity is reduced, but motor durability decreases

Engineering Contradiction:

Improvecontrol system complexityVSAvoidmotor durability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS11190125B2Control system, vehicle system, and control method

Publication Date: 2021.11.30 HONDA MOTOR CO LTD

AI summary

A control system includes a power inverter configured to convert direct current (DC) power into alternating current (AC) power, an electric motor configured to be driven using the AC power output by the power inverter, and a controller configured to control the AC power by performing switching between multi-pulse control and one-pulse control on the basis of electric power loss of the electric motor and the power inverter and noise of the electric motor, the controller being a control device configured to control the power inverter.