Wireless Power Transmission Device Frequency Control

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Solution Overview

Problem

Existing wireless power transmission systems face challenges in maintaining both constant voltage output and high transmission efficiency, especially when the load impedance or environmental conditions change, due to mismatch between the resonant frequency for maximum efficiency and the required voltage for charging devices.

Innovation Solution

A power transmission device with an oscillator, power transmission antenna, memory for required voltage values, and a control circuitry that adjusts the output time ratio and frequency of AC power to converge received voltage, current, or power within stipulated values, while determining the frequency for maximum efficiency, ensuring efficient power delivery to varying loads and environments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the resonant frequency is adjusted to maximize transmission efficiency, then the energy transmission efficiency is improved, but the output voltage may deviate from the required voltage for the power receiving device

Engineering Contradiction:
Improvetransmission efficiencyVSAvoidvoltage stability
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent applies parameter changes by adjusting the resonant frequency and coupling coefficient as controllable parameters to optimize both transmission efficiency and voltage output. The control circuit varies these parameters dynamically to achieve maximum efficiency while maintaining voltage within acceptable ranges for the power receiving device.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements feedback control by monitoring the actual voltage output and transmission efficiency, then adjusting the resonant frequency and coupling coefficient accordingly. The control circuit uses feedback signals from the power receiving device to maintain optimal operating conditions despite load variations or environmental changes.

Inventive Principle:
Principle #23Feedback

2Loss of energy

If the coupling coefficient is increased to improve power transfer efficiency, then the transmission efficiency is improved, but the system becomes more sensitive to load fluctuations and environmental changes

Engineering Contradiction:
Improvetransmission efficiencyVSAvoidload adaptation capability
Core Design Contradiction:
Loss of energyVSAdaptability or versatility

Solution Approach 1:

The patent applies dynamics by making the coupling coefficient adjustable rather than fixed. The control circuit dynamically modifies the coupling coefficient based on real-time operating conditions, including load variations and environmental factors, allowing the system to adapt while maintaining high transmission efficiency.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent uses parameter changes by varying the coupling coefficient and resonant frequency to optimize performance under different operating conditions. This allows the system to maintain high efficiency while adapting to load fluctuations and environmental changes through controlled parameter adjustment.

Inventive Principle:
Principle #35Parameter changes

3Loss of energy

If the resonant frequency is optimized for maximum efficiency at a specific load, then the transmission efficiency is improved, but the system cannot maintain efficiency when the load impedance changes

Engineering Contradiction:
Improvetransmission efficiencyVSAvoidimpedance matching capability
Core Design Contradiction:
Loss of energyVSAdaptability or versatility

Solution Approach 1:

The patent applies parameter changes by adjusting both the resonant frequency and coupling coefficient in response to load impedance variations. This dual-parameter adjustment allows the system to maintain optimal transmission efficiency across a wide range of load conditions rather than being optimized for a single operating point.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements dynamic adaptation by continuously monitoring load impedance and adjusting the resonant frequency and coupling coefficient accordingly. This dynamic control enables the system to maintain high transmission efficiency despite changes in load characteristics or environmental conditions.

Inventive Principle:
Principle #15Dynamics

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 solution enables stable voltage output and maximized transmission efficiency across different load impedances and environmental changes, preventing damage to charging devices and optimizing power transfer.

Implementation Method 1

a power transmission antenna that transmits the AC power output from the oscillator, for output to a load of a power receiving device

Methodology Applied
Scientific EffectElectromagnetic coupling: Electromagnetic Induction

Implementation Method 2

two resonators are magnetically coupled by way of leakage (evanescent tail) of vibration energy generated in space in the perimeter of the resonators (antennas)

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 3

a technology which transmits electric power wirelessly (noncontact), using a new method called resonant magnetic coupling

Methodology Applied
Scientific EffectResonant magnetic coupling: Resonance

Implementation Method 4

two resonators are magnetically coupled by way of leakage (evanescent tail) of vibration energy generated in space

Methodology Applied
Scientific EffectMagnetic coupling: Magnetic Field

Data Source

PatentEP3032698B1Wireless power-transfer system and power-transmission device
Publication Date: 2018.10.24 PANASONIC HOLDINGS CORP
  • EP3032698B1 patent drawingFigure 1A~1B
  • EP3032698B1 patent drawingFigure 2A
  • EP3032698B1 patent drawingFigure 2B

AI summary

A power transmission device in a wireless power transmission system according to the present disclosure includes: an oscillator that outputs AC power converted from the DC power via a first output end connected to the first switching device and a second output end connected to the second switching device; a power transmission antenna that transmits the AC power output from the oscillator, for output to a load of a power receiving device; memory that holds a predetermined value indicating required voltage of the power receiving device; a receiving circuit that receives the voltage supplied to the load of the power receiving device; and a control circuitry that changes an output time ratio of power of the AC voltage output from the oscillator, by using the first switching device and the second switching device to change times at which voltage at the first output end of the oscillator and voltage at the second output end are to be of the same potential, changes a frequency of voltage of the AC power output from the oscillator and determines a frequency of AC power where efficiency of the AC power is greatest, and converges at least one of the received voltage, current, and power, to a range of the predetermined value, and outputs AC power of which the efficiency is greatest to the load.