Resonant Wireless Power Circuit for Stable Output Voltage

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Solution Overview

Problem

Existing wireless power transmission systems for customer premise equipment (CPE) face challenges in maintaining stable output voltage due to dynamic changes in load, leading to untimely power system shutdowns due to slow response times in loop control adjustments.

Innovation Solution

The implementation of a wireless power transmission system using series resonant circuits with a transmitter and receiver, where the transmitter includes a DC/AC inverter circuit, a resonant inductor, and a compensation inductor, and the receiver includes an AC/DC rectifier circuit, a resonant inductor, and a compensation inductor, allowing for electromagnetic induction and maintaining a constant voltage output by adjusting the operating frequency based on resonant frequency and coupling coefficient calculations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If loop control is used to maintain stable output voltage, then output voltage stability is improved, but response time becomes slow causing power system shutdowns

Engineering Contradiction:
Improveoutput voltage stabilityVSAvoidresponse time
Core Design Contradiction:
Stability of the object's compositionVSLoss of time

Solution Approach 1:

The patent changes the operating frequency parameter of the transmitter to match the resonant frequency of the series resonant circuit. By operating at resonant frequency, the system achieves both fast response to load changes and stable output voltage without the delays associated with loop control. The frequency is calculated based on the coupling coefficient and resonant frequency parameters.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent utilizes electromagnetic resonance in the series resonant circuit, which operates at a specific resonant frequency. This resonance phenomenon enables the system to respond rapidly to load changes while maintaining stable voltage output, eliminating the slow response problem of conventional loop control methods.

Inventive Principle:
Principle #18Mechanical vibration

2Device complexity

If wireless power transmission is implemented, then installation complexity is reduced, but maintaining stable output voltage under dynamic load becomes difficult

Engineering Contradiction:
Improveinstallation complexityVSAvoidoutput voltage stability
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The patent calculates and adjusts the operating frequency based on the coupling coefficient between transmitter and receiver coils, and the resonant frequency of the series resonant circuit. This parameter adjustment enables stable output voltage under dynamic load conditions while maintaining the wireless transmission advantage of reduced installation complexity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system incorporates feedback mechanisms where the calculated operating frequency is continuously adjusted based on coupling coefficient measurements and resonant frequency detection. This feedback loop ensures stable output voltage is maintained even as load conditions change, without requiring complex wired installations.

Inventive Principle:
Principle #23Feedback

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 ensures a stable output voltage that is independent of the receiver's load, enabling dynamic response and preventing power system shutdowns by maintaining a constant voltage operating frequency, even with changes in load conditions.

Implementation Method 1

power at the transmitter is transmitted to the receiver through electromagnetic induction between the first resonant inductor and the second resonant inductor

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

series resonant circuits with a transmitter and receiver, where the transmitter includes a DC/AC inverter circuit, a resonant inductor, and a compensation inductor

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP4068571B1Wireless energy transmission system
Publication Date: 2023.12.13 HUAWEI DIGITAL POWER TECH CO LTD
  • EP4068571B1 patent drawingFigure 1~2A-1
  • EP4068571B1 patent drawingFigure 2A-2
  • EP4068571B1 patent drawingFigure 2A-3~2A-4

AI summary

This application provides a wireless power transmission system. The system includes a transmitter and a receiver, where the transmitter includes a DC/AC inverter circuit, a first resonant inductor, a first capacitor, and a first compensation inductor that are connected in series; and the receiver includes an AC/DC rectifier circuit, a second resonant inductor, a second capacitor, and a second compensation inductor that are connected in series; and power at the transmitter is transmitted to the receiver through electromagnetic induction between the first resonant inductor and the second resonant inductor, and the AC/DC rectifier circuit is configured to provide the rectified power to a load of the receiver. This solution is applicable to a wireless power supply scenario or a wireless charging scenario.