Wireless Power Feeder Non-Resonant Driving

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Solution Overview

Problem

Current wireless power feeding technologies using magnetic field resonance face inefficiencies due to unwanted resonance frequencies and increased capacitor size, which affects power transmission efficiency and size constraints.

Innovation Solution

A wireless power feeder system that supplies AC current to a feeding coil at a drive frequency coinciding with the resonance frequency of the receiving coil, eliminating the need for a resonance circuit on the power feeding side and reducing dielectric loss by not forming a resonance circuit with the feeding coil, allowing high-efficiency power transmission without the feeding coil resonating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a resonance circuit is formed on the power feeding side to achieve magnetic field resonance power transmission, then power transmission efficiency is improved, but unwanted resonance frequencies are generated causing interference

Engineering Contradiction:

Improvepower transmission efficiencyVSAvoidunwanted resonance frequencies

Core Design Contradiction:

Loss of energyVSObject-generated harmful factors

Solution Approach 1:

The patent removes the resonance circuit (capacitor) from the power feeding side, extracting only the necessary resonance function to the power receiving side. This eliminates the source of unwanted resonance frequencies while preserving the beneficial magnetic field coupling effect for power transmission.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of making both the power feeding side and power receiving side resonate at the same frequency, the patent inverts the approach by making only the power receiving side resonate while the power feeding side operates without resonance. This reversal eliminates the dual-resonance problem while maintaining power transmission efficiency.

Inventive Principle:

Principle #13The other way round (Inversion)

2Volume of stationary object

If the resonance frequency is set to a low frequency band to reduce capacitor size, then device size is reduced, but dielectric loss increases

Engineering Contradiction:

Improvecapacitor sizeVSAvoiddielectric loss

Core Design Contradiction:

Volume of stationary objectVSLoss of energy

Solution Approach 1:

The patent removes the capacitor from the power feeding side entirely, eliminating the source of dielectric loss associated with low-frequency resonance circuits. The resonance function is extracted and relocated to the power receiving side, allowing the power feeding side to operate without the harmful effects of large capacitors.

Inventive Principle:

Principle #2Taking out (Extraction)

3Loss of energy

If the drive frequency tracks the resonance frequency fr1, then power transmission efficiency is maximized, but the drive frequency may accidentally track the unwanted resonance frequency fr2

Engineering Contradiction:

Improvepower transmission efficiencyVSAvoidfrequency tracking accuracy

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

By removing the resonance circuit from the power feeding side, the patent eliminates the mechanism that generates the unwanted resonance frequency fr2. This leaves only the desired resonance frequency fr1 (at the power receiving side) for the drive frequency to track, ensuring accurate frequency tracking without accidental deviation to fr2.

Inventive Principle:

Principle #2Taking out (Extraction)

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

This approach enables high-efficiency wireless power transmission by eliminating unnecessary resonance points and reducing the size and cost of the power feeder, while maintaining high power transmission efficiency even at varying inter-coil distances.

Implementation Method 1

feeds power from a feeding coil to a receiving coil by wireless based on a magnetic-field resonance phenomenon between the feeding coil and receiving coil

Methodology Applied

Scientific EffectMagnetic field resonance: Resonance

Implementation Method 2

a power transmission control circuit that supplies AC current at a drive frequency to the feeding coil so as to make the feeding coil feed AC power

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS9058928B2Wireless power feeder and wireless power transmission system

Publication Date: 2015.06.16 TDK CORP

AI summary

A wireless power feeder 116 feeds power from a feeding coil L2 to a receiving coil L3 by wireless based on a magnetic field resonance phenomenon between the feeding coil L2 and receiving coil L3. A power transmission control circuit 200 supplies AC current at a drive frequency fo to the feeding coil L2. The feeding coil L2 outputs AC power in substantially a non-resonant state with respect to circuit elements on the power feeding side. Then, power is supplied to a receiving coil circuit 130 by a magnetic field resonance between the feeding coil L2 and receiving coil L3.