Wireless Power Receiver Impedance Control

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Solution Overview

Problem

Current wireless power feeding technologies, particularly the magnetic field resonance type, face challenges in accurately controlling the magnitude of receiving power, leading to inefficiencies due to varying factors affecting the power transmission state and impedance adjustment methods.

Innovation Solution

A wireless power receiver system that includes a receiving coil, a loading circuit, and a power controller with a measurement unit and an adjustment unit to optimize impedance, allowing real-time adjustment of receiving power by measuring and adjusting resistance and reactance components in the loading circuit to maximize power transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If magnetic field resonance type wireless power feeding is used to achieve high power transmission efficiency in intermediate range, then power transmission efficiency is improved, but receiving power control precision deteriorates

Engineering Contradiction:

Improvepower transmission efficiencyVSAvoidreceiving power control precision

Core Design Contradiction:

Loss of energyVSMeasurement precision

Solution Approach 1:

The patent implements a feedback control mechanism where the power controller continuously measures the receiving power and adjusts the impedance of the loading circuit based on the measured value. This closed-loop feedback system enables precise control of receiving power while maintaining high transmission efficiency through magnetic field resonance.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent changes the impedance parameter of the loading circuit to control the receiving power magnitude. By adjusting the impedance (including resistance and reactance components), the system can precisely control the amount of power received while operating in magnetic field resonance mode for high efficiency.

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If impedance adjustment is performed to control receiving power magnitude, then receiving power control is improved, but device complexity increases

Engineering Contradiction:

Improvereceiving power controlVSAvoidimpedance adjustment mechanism complexity

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The power controller performs multiple functions: it measures receiving power, calculates optimal impedance values, and adjusts the loading circuit impedance. This multi-functional approach consolidates control operations into a single device, improving ease of operation without proportionally increasing overall system complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system automatically adjusts its own impedance based on measured receiving power without requiring external intervention. The power controller self-regulates the loading circuit impedance to maintain optimal power transfer, enabling autonomous operation and simplifying user interaction.

Inventive Principle:

Principle #25Self-service

3Stability of the object's composition

If variable capacitor is adjusted based on map assumption to maintain receiving power, then power stability is improved, but measurement precision deteriorates

Engineering Contradiction:

Improvereceiving power stabilityVSAvoidreceiving power measurement accuracy

Core Design Contradiction:

Stability of the object's compositionVSMeasurement precision

Solution Approach 1:

The patent replaces the mechanical map-based adjustment approach with an electronic calculation and control system. The power controller electronically calculates the optimal impedance based on real-time measurements and automatically adjusts the loading circuit, eliminating the need for pre-programmed maps and improving measurement precision through direct electronic control.

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

Enables precise adjustment of receiving power to maximize transmission efficiency, ensuring consistent and optimal power delivery even with changes in the inter-coil distance or other environmental factors.

Implementation Method 1

receives, at a receiving coil, AC power fed from a feeding coil by wireless using a magnetic field resonance phenomenon between the feeding coil and receiving coil

Methodology Applied

Scientific EffectMagnetic field resonance phenomenon: Resonance

Implementation Method 2

a loading coil that is magnetically coupled to the receiving coil to receive the AC power from the receiving coil

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS9356449B2Wireless power receiver, wireless power transmission system, and power controller

Publication Date: 2016.05.31 TDK CORP

AI summary

A wireless power receiver receives, at a receiving coil, AC power fed from a feeding coil by wireless using a magnetic field resonance phenomenon between the feeding coil and receiving coil. The wireless power receiver includes a loading circuit and a power controller. The loading circuit includes a loading coil that is magnetically coupled to the receiving coil to receive the AC power from the receiving coil and a load that receives the AC power supplied from the loading coil. The power controller includes a measurement unit and an adjustment unit. The measurement unit measures the receiving power of the load. The adjustment unit brings the receiving power close to its maximum value by changing the impedance of the loading circuit.