Space Vector Modulation for Inverter EMI and CMV Reduction

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Solution Overview

Problem

Existing power converters generate significant electromagnetic interference (EMI) noise, particularly in aerospace applications like aircraft propulsion, necessitating bulky passive EMI filters and requiring improved active EMI mitigation techniques.

Innovation Solution

A modified space vector modulation (SVM) scheme that maps switching states onto a two-dimensional hexagonal space vector diagram, identifies and removes redundant vectors contributing to common mode voltage (CMV), and introduces a fourth vector to balance dc-link capacitors, optimizing the switching sequence to minimize CMV without additional circuitry.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If passive EMI filters are used to reduce EMI noise, then EMI attenuation is improved, but the filter size and weight increase

Engineering Contradiction:

ImproveEMI noiseVSAvoidfilter weight

Core Design Contradiction:

Object-affected harmful factorsVSWeight of stationary object

Solution Approach 1:

The patent replaces the mechanical/passive EMI filter system with a software-based control system that uses modified space vector modulation algorithms to actively mitigate EMI noise at its source, eliminating the need for bulky passive filters

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent extracts and removes the harmful common mode voltage component from the output of the voltage source inverter through software-based modulation control, preventing EMI noise generation rather than filtering it afterward

Inventive Principle:

Principle #2Taking out (Extraction)

2Ease of operation

If conventional space vector modulation is used to control inverter switching, then output voltage control is achieved, but common mode voltage and EMI noise are generated

Engineering Contradiction:

Improvevoltage controlVSAvoidcommon mode voltage

Core Design Contradiction:

Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent modifies specific aspects of the space vector modulation algorithm to locally optimize for reduced common mode voltage while maintaining overall voltage control functionality, by selectively choosing switching states that minimize CMV

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the modulation parameters and switching state selection criteria in the SVM algorithm to minimize common mode voltage generation while maintaining the desired output voltage control performance

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS20250309758A1Space vector modulation for EMI mitigation in power converters

Publication Date: 2025.10.02 COLLINS AEROSPACE IRELAND LTD

AI summary

A method of implementing a space vector pulse width modulation scheme. The method includes: mapping switching states for an n-phase, where n is an integer, multi-level inverter onto a two-dimensional hexagonal space vector diagram; identifying redundant vectors in the space vector diagram and removing redundant vectors associated with a common mode voltage current contribution of more than a predetermined threshold; identifying a location in the space vector diagram of a voltage reference vector; identifying a sector of the space vector diagram defined by four vectors within which the voltage reference vector is located; and determining duty cycles and switching states associated with the four vectors to synthesise the voltage reference vector.