MEMS Current Sensor Flexible Substrate Non-Contact Measurement

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Solution Overview

Problem

Traditional current sensors are limited by their large size, need for an external electric source, and inability to measure multiple conductor wires, making them unsuitable for efficient energy management in residential and industrial settings.

Innovation Solution

A micro-electro-mechanical system (MEMS) current sensing apparatus with a flexible substrate, an MEMS sensing unit, and a readout circuit that uses Faraday's law of induction to measure current flow in conducting wires without contact, featuring a conductor coil with high magnetic permeability and a C-shaped clamp for secure attachment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional current sensors are used to measure energy usage, then current detection can be achieved, but the device size becomes large and requires external electric sources

Engineering Contradiction:
Improvecurrent detection capabilityVSAvoidsensor size
Core Design Contradiction:
Measurement precisionVSVolume of moving object

Solution Approach 1:

The patent replaces traditional mechanical/electronic current sensors with a MEMS-based sensing unit that utilizes electromagnetic induction. The sensing unit comprises a conductor coil that detects current through induced electromagnetic fields rather than direct electrical contact, enabling compact integration while maintaining measurement capability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the operating principle from direct electrical measurement to electromagnetic field-based detection. By using Faraday's law of induction, the system transforms the measurement approach, allowing the sensor to operate passively without external power sources and achieve miniaturization through MEMS fabrication techniques.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If traditional current sensors are used, then current measurement is possible, but the sensor requires external electric sources to operate

Engineering Contradiction:
Improvecurrent measurement capabilityVSAvoidexternal electric source requirement
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The MEMS sensing unit operates passively by harvesting energy from the electromagnetic field generated by the current-carrying wire itself. The conductor coil in the sensing unit is induced by the magnetic field from the wire, generating voltage without requiring any external power source, thus making the sensor self-powered.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces active electronic sensing circuits that require power with a passive electromagnetic induction-based sensing unit. This substitution eliminates the need for external electric sources while maintaining measurement functionality through fundamental electromagnetic principles.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If traditional current sensors are used, then single wire measurement can be achieved, but the sensor cannot be applied to multiple conductor wires

Engineering Contradiction:
Improvesingle wire measurement capabilityVSAvoidmulti-conductor measurement capability
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The MEMS current sensing apparatus is designed with a flexible substrate and adjustable sensing unit that can accommodate multiple conductor wires of varying shapes and sizes. The flexible substrate allows the sensor to conform to different wire configurations, enabling universal application across single or multiple conductors without requiring different sensor types.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent introduces flexibility and adaptability through the flexible substrate and adjustable mounting mechanisms. The sensing unit can be positioned and configured dynamically to suit different wire arrangements, whether single or multiple conductors, making the sensor versatile for various electrical configurations.

Inventive Principle:
Principle #15Dynamics

4Volume of moving object

If MEMS sensing unit with conductor coil is used, then compact size is achieved, but the coil linewidth must be precisely controlled for optimal performance

Engineering Contradiction:
Improvesensor compactnessVSAvoidcoil linewidth control
Core Design Contradiction:
Volume of moving objectVSManufacturing precision

Solution Approach 1:

The patent optimizes the conductor coil geometry by making the linewidth parallel to the wire larger than the linewidth perpendicular to the wire. This asymmetric design enhances the coupling between the coil and the magnetic field from the wire, improving sensitivity while remaining compatible with standard MEMS fabrication capabilities.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The conductor coil is designed with non-uniform linewidth characteristics, with the parallel dimension being larger than the perpendicular dimension. This local quality variation optimizes the magnetic coupling in the critical direction while maintaining manufacturability through conventional MEMS processes.

Inventive Principle:
Principle #3Local quality

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 MEMS current sensing apparatus provides a compact, non-contact, and passive solution for accurately measuring current flow, enabling efficient energy management and reducing energy waste by integrating seamlessly with conducting wires of varying shapes and sizes.

Implementation Method 1

a sensing unit outputting a response to a electromagnetic field induced by a current flowing in the conducting wire

Methodology Applied
Scientific EffectFaraday's law of induction: Electromagnetic Induction

Implementation Method 2

a conductor coil having a material of magnetic permeability therein

Methodology Applied
Scientific EffectMagnetic permeability: Magnetic Field

Data Source

PatentEP2439544B1MEMS current sensing apparatus
Publication Date: 2015.10.28 IND TECH RES INST
  • EP2439544B1 patent drawingFigure 1
  • EP2439544B1 patent drawingFigure 2
  • EP2439544B1 patent drawingFigure 3

AI summary

The invention discloses an MEMS-based current sensing apparatus including: a flexible substrate joined onto an conducting wire; a sensing unit formed of an MEMS structure and disposed on the flexible substrate, the sensing unit outputting a response to a electromagnetic field induced by a current flowing in the conducting wire; and a readout circuit disposed on the flexible substrate and coupled to the sensing unit, the readout circuit monitoring the response to the electromagnetic field and calculating the amount of the current flow.