Measuring Shunt With Annular Magnetic Core for Decoupling

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing measuring shunts for parallel-connected half-bridges of electronic switches in power converters lack effective decoupling and accurate current measurement, often relying on costly inductors and suffering from voltage gradient issues.

Innovation Solution

A measuring shunt with a resistance element and an annular magnetic core that provides inductance for decoupling and includes auxiliary contacts for improved measurement accuracy, allowing four-wire measurement and filtering of voltage gradients.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If inductors are used to decouple electronic switches in parallel half-bridges, then decoupling performance is improved, but cost increases

Engineering Contradiction:

Improvedecoupling performanceVSAvoidcost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent combines the measuring shunt function with the decoupling function into a single integrated component. The measuring shunt includes a resistance element for current measurement and an annular magnetic core that provides inductance for decoupling parallel half-bridges, eliminating the need for separate inductors and reducing overall system cost.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The measuring shunt is designed to perform multiple functions simultaneously: it measures phase currents through its resistance element and provides decoupling for parallel half-bridges through its magnetic core's inductance. This multi-functional design reduces component count and system complexity while maintaining performance.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Device complexity

If conventional measuring shunts are used without additional decoupling components, then device complexity is reduced, but decoupling of parallel half-bridges is insufficient

Engineering Contradiction:

Improvecomponent countVSAvoiddecoupling effectiveness

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The measuring shunt integrates both measurement and decoupling functions in one component. The magnetic core surrounding the resistance element provides the necessary inductance for decoupling parallel half-bridges, while the resistance element maintains its current measurement capability, achieving both goals without additional components.

Inventive Principle:

Principle #5Merging (Combining)

3Device complexity

If standard two-wire measurement is used, then device complexity is low, but measurement accuracy deteriorates due to voltage gradients

Engineering Contradiction:

Improvemeasurement circuit complexityVSAvoidcurrent measurement accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The measuring shunt divides the measurement function into separate terminals: two main contacts for current flow and two auxiliary contacts for voltage measurement. This segmentation allows four-wire measurement where the voltage measurement circuit draws minimal current through the auxiliary contacts, eliminating voltage drop errors and improving measurement accuracy.

Inventive Principle:

Principle #1Segmentation

4Reliability

If the magnetic core is placed close to the resistance element, then inductance is increased for better decoupling, but voltage induction at measurement points increases causing measurement errors

Engineering Contradiction:

Improvedecoupling performanceVSAvoidmeasurement signal accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The measuring shunt separates the current path (through main contacts and resistance element) from the voltage measurement path (through auxiliary contacts). The four-wire measurement configuration ensures that voltage sensing currents are minimal, reducing the impact of magnetically induced voltages from the magnetic core on measurement accuracy.

Inventive Principle:

Principle #1Segmentation

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

Enables accurate current measurement and decoupling of electronic switches in parallel half-bridges without additional components, while reducing voltage gradients and enhancing overall functionality.

Implementation Method 1

The magnetic core extending around the resistance element imparts to the measuring shunt an inductance that can be used to decouple electronic switches in half-bridges connected in parallel

Methodology Applied

Scientific EffectInductance: Inductor

Implementation Method 2

A magnetic core which extends in an annular manner around the middle section of the resistance element

Methodology Applied

Scientific EffectMagnetic field: Magnetic Field

Implementation Method 3

a resistance element with two main contacts and a middle section extending between the main contacts for conducting an electric current between the two main contacts through the middle section

Methodology Applied

Scientific EffectElectrical resistance: Electrical Resistance

Data Source

PatentUS11385262B2Measuring shunt

Publication Date: 2022.07.12 SIEMENS AG

AI summary

A measuring shunt includes a resistance element and a magnetic core. The resistance element includes two main contacts and a middle section extending between the main contacts for conducting an electrical current between the two main contacts through the middle section. The magnetic core extends in an annular manner around the middle section of the resistance element.