Wireless Power Transmitter Impedance Control for Coupling Variations

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Solution Overview

Problem

Existing wireless power transmission systems face reduced power transmission efficiency due to varying coupling states between the transmitter and receiver, as impedance on the load side is fixed, leading to inefficiencies in power transfer.

Innovation Solution

A method is developed to detect the coupling factor between resonant coils and control the impedance of the load accordingly, ensuring stable power transmission by adjusting the transmission power based on the detected coupling state, thereby improving power transmission efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If impedance of load side is fixed in wireless power transmission system, then device complexity is reduced, but power transmission efficiency deteriorates as coupling state varies

Engineering Contradiction:
Improveimpedance control complexityVSAvoidpower transmission efficiency
Core Design Contradiction:
Device complexityVSLoss of energy

Solution Approach 1:

The patent applies dynamics by transitioning from fixed impedance to dynamically adjustable impedance on the load side. The system continuously monitors coupling state and adjusts impedance in real-time to match optimal values, enabling the system to adapt to varying coupling conditions and maintain high power transmission efficiency throughout the power transfer process.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements parameter changes by modifying the impedance parameter of the load side based on detected coupling state. By changing impedance values according to coupling conditions, the system optimizes power transfer efficiency dynamically, resolving the contradiction between device complexity and energy loss.

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If impedance of load side is adjusted according to coupling state, then power transmission efficiency is improved, but device complexity increases

Engineering Contradiction:
Improvepower transmission efficiencyVSAvoidimpedance control system complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent employs feedback by implementing a closed-loop control system that detects coupling state and uses this information to adjust impedance on the load side. The feedback mechanism enables automatic optimization of power transmission efficiency without requiring complex manual intervention, balancing the trade-off between efficiency improvement and system complexity.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system applies self-service by enabling the wireless power transmission system to automatically monitor its own coupling state and adjust its impedance accordingly. This self-regulating capability allows the system to optimize its own performance without external control, reducing the burden on external control systems while maintaining high efficiency.

Inventive Principle:
Principle #25Self-service

3Stability of the object's composition

If coupling factor is detected and transmission power is controlled accordingly, then power transmission stability is improved, but measurement and control complexity increases

Engineering Contradiction:
Improvepower transmission stabilityVSAvoiddetection and control system complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent uses feedback by implementing a detection and control loop that monitors coupling factor and adjusts transmission power based on detected values. This feedback mechanism ensures stable power transmission by continuously adapting to coupling variations, while the automated nature of the feedback loop minimizes the complexity burden.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system applies preliminary action by detecting coupling state in advance and proactively adjusting transmission power before significant efficiency losses occur. This predictive approach maintains power transmission stability by preparing the system for upcoming coupling variations, reducing the complexity of real-time emergency corrections.

Inventive Principle:
Principle #10Preliminary action

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 enhances power transmission efficiency and stability by dynamically adjusting impedance in response to coupling variations, resulting in improved frequency-to-power transmission efficiency characteristics.

Implementation Method 1

a transmission resonant coil unit (22) including a transmission resonant coil (L2), a capacitor (C2) and a resistor (R2), wherein one terminal of the transmission resonant coil (L2) is connected to one terminal of the capacitor (C2) and the other terminal of the transmission resonant coil (L2) is connected to one terminal of the resistor (R2)

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a reception resonant coil unit (31) including a reception resonant coil (L3), a capacitor (C3) and a resistor (R3)... a coupling factor between the transmission resonant coil (L2) and the reception resonant coil (L3)

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP2761724B1Wireless power transmitter
Publication Date: 2019.12.04 LG INNOTEK CO LTD
  • EP2761724B1 patent drawingFigure 1~2
  • EP2761724B1 patent drawingFigure 3
  • EP2761724B1 patent drawingFigure 4

AI summary

Disclosed is a wireless power transmitter which transmits power through a wireless power receiver to a load side. The wireless power transmitter includes a power source for generating AC power; a transmission coil for wirelessly transmitting the AC power to a reception coil of the wireless power receiver; and a detecting unit for detecting a coupling state between the transmission coil and the reception coil.