Integrated Current Sensing Transformer for Dual Loop Circuits

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Solution Overview

Problem

Current sensing transformers are not cost-effective or compact when used to measure currents in two loop circuits, as they require multiple transformers, increasing the volume and weight of electronic devices.

Innovation Solution

An integrated current sensing transformer with a bobbin, magnetic core assembly, and multiple winding elements allows sensing of two test loop circuits using a single transformer, reducing the need for multiple devices and minimizing size and weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If two separate current sensing transformers are used to measure currents in two loop circuits, then the current sensing function is achieved, but the volume and weight of the electronic device increase

Engineering Contradiction:

Improvecurrent sensing functionVSAvoiddevice weight

Core Design Contradiction:

ReliabilityVSWeight of stationary object

Solution Approach 1:

The patent combines two separate current sensing transformers into a single integrated transformer that can sense currents in two different loop circuits simultaneously. The integrated transformer includes a bobbin with a magnetic core assembly and multiple winding elements (first primary winding element, second primary winding element, and secondary winding element) that enable dual circuit sensing functionality in one device, thereby reducing the overall weight and volume compared to using two separate transformers.

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If two separate current sensing transformers are used to measure currents in two loop circuits, then the current sensing function is achieved, but the volume of the electronic device increases

Engineering Contradiction:

Improvecurrent sensing functionVSAvoiddevice volume

Core Design Contradiction:

ReliabilityVSVolume of stationary object

Solution Approach 1:

The patent combines two separate current sensing transformers into a single integrated transformer that can sense currents in two different loop circuits simultaneously. The integrated transformer includes a bobbin with a magnetic core assembly and multiple winding elements (first primary winding element, second primary winding element, and secondary winding element) that enable dual circuit sensing functionality in one device, thereby reducing the overall volume compared to using two separate transformers.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If two separate current sensing transformers are used to measure currents in two loop circuits, then the current sensing function is achieved, but the cost increases

Engineering Contradiction:

Improvecurrent sensing functionVSAvoidnumber of components

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

Inventive Principle:

Principle #5Merging (Combining)

4Ease of operation

If a resistor-based current sensor is used to measure current, then the current measurement is simple, but power loss increases due to heat generation

Engineering Contradiction:

Improvemeasurement simplicityVSAvoidpower loss

Core Design Contradiction:

Ease of operationVSLoss of energy

Solution Approach 1:

The patent replaces the resistor-based current sensing method with a transformer-based current sensing method. Instead of using a test resistor that converts current to heat (causing power loss), the invention uses electromagnetic induction through primary and secondary winding elements to sense current. This substitution eliminates the need for power-dissipating resistors while maintaining current measurement capability, thereby reducing energy loss.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 solution effectively senses currents in two loop circuits with reduced cost, volume, and weight, providing proportional sensing currents without the inefficiencies of multiple transformers.

Implementation Method 1

The magnetic core assembly is partially embedded into the receptacle for providing a closed path of magnetic flux

Methodology Applied

Scientific EffectMagnetic flux: Magnetic Field

Implementation Method 2

The secondary winding element is wound around the bobbin for outputting a sensing current when either the first test current or the second test current is sensed

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS7671580B2Integrated current sensing transformer and current sensing circuit using such transformer

Publication Date: 2010.03.02 DELTA ELECTRONICS INC(CN)

AI summary

An integrated current sensing transformer includes a bobbin, a magnetic core assembly, a first primary winding element, a second primary winding element, a secondary winding element. The bobbin has a receptacle therein. The magnetic core assembly is partially embedded into the receptacle for providing a closed path of magnetic flux. The first primary winding element is wound around the bobbin for inputting a first test current therein. The second primary winding element is wound around the bobbin for inputting a second test current therein. The secondary winding element is wound around the bobbin for outputting a sensing current when either the first test current or the second test current is sensed. The magnitude of the sensing current is directly proportional to the magnitude of the first test current or the second test current.