Integrated Inverter Filter Merging Common and Differential Mode

Solution Overview

Problem

Existing inverter filters require separate common mode and differential mode filters, which are costly and large in size, and do not effectively manage common mode currents in low voltage systems.

Innovation Solution

An inverter filter design that integrates a differential mode filter with a common mode filter function using a node, inductors, capacitors, and resistors, where the common mode filter comprises a resistor and capacitor in series with the node grounded, reducing common mode currents at a lower cost.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If separate common mode filter and differential mode filter are used, then common mode currents are filtered, but the size and cost increase significantly

Engineering Contradiction:

Improvecommon mode currentsVSAvoidfilter size

Core Design Contradiction:

Object-affected harmful factorsVSVolume of stationary object

Solution Approach 1:

The patent combines the common mode filter and differential mode filter into a single integrated filter unit. The common mode inductor and differential mode inductors share the same magnetic core structure, allowing both filtering functions to be performed by one compact device rather than requiring separate filter components.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The integrated filter structure serves multiple functions simultaneously: the common mode inductor filters common mode currents while the differential mode inductors filter differential mode currents, and both share a common magnetic core and capacitor arrangement, making the filter multi-functional and space-efficient.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Object-affected harmful factors

If separate common mode filter and differential mode filter are used, then common mode currents are filtered, but the cost increases significantly

Engineering Contradiction:

Improvecommon mode currentsVSAvoidfilter cost

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent combines the common mode filter and differential mode filter into a single integrated filter unit. The common mode inductor and differential mode inductors share the same magnetic core structure, allowing both filtering functions to be performed by one compact device rather than requiring separate filter components.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The integrated filter structure serves multiple functions simultaneously: the common mode inductor filters common mode currents while the differential mode inductors filter differential mode currents, and both share a common magnetic core and capacitor arrangement, making the filter multi-functional and space-efficient.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If traditional separate filters are used, then filtering function is provided, but the structure is complex and occupies more space

Engineering Contradiction:

Improvefiltering functionVSAvoidfilter structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the common mode filter and differential mode filter into a single integrated filter unit. The common mode inductor and differential mode inductors share the same magnetic core structure, allowing both filtering functions to be performed by one compact device rather than requiring separate filter components.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The filter design nests the differential mode inductors within the same magnetic core structure as the common mode inductor, creating a compact nested arrangement where components are efficiently packed together to reduce overall filter size and structural complexity.

Inventive Principle:

Principle #7Nested doll (Nesting)

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 integrated filter design significantly reduces common mode currents while maintaining a compact and cost-effective solution, addressing the size and cost issues of traditional filters.

Implementation Method 1

an inductor electrically connected between the first terminal and the second terminal

Methodology Applied

Scientific EffectElectromagnetic Induction: Electromagnetic Induction

Implementation Method 2

a first capacitor electrically connected between the inductor and the node

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 3

The common mode or zero sequence loop of current flow that is largely orthogonal in terms of energy or power transfer to the intended differential three-phase power circuit

Methodology Applied

Scientific EffectParasitic Capacitance: Parasitic Capacitance

Implementation Method 4

a resistor, and a second capacitor electrically connected in series with the resistor between the node and the third terminal

Methodology Applied

Scientific EffectJoule Heating: Joule Heating

Data Source

PatentUS8325500B2Inverter filter including differential mode and common mode, and system including the same

Publication Date: 2012.12.04 EATON INTELLIGENT POWER LTD

AI summary

An inverter filter is for a plurality of phases. The inverter filter includes a node; a differential mode filter including for each of the phases a first terminal, a second terminal, an inductor electrically connected between the first terminal and the second terminal, and first capacitor electrically connected between the inductor and the node. The inverter filter also includes a third terminal structured to be grounded, and a common mode filter. The common mode filter includes a resistor, and a second capacitor electrically connected in series with the resistor between the node and the third terminal.