Single Inductor Tuner and Rectifier for Wireless Power Transfer

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Solution Overview

Problem

High quality factor (Q) magnetic resonance wireless power transfer (WPT) receivers are vulnerable to stability and sensitivity issues due to frequency drifts, component tolerance variations, environmental effects, and misalignment, which degrade power transfer capability.

Innovation Solution

A compact circuit structure with a central inductor coupled between switching networks, which senses tuning conditions to adaptively generate a time period for charging and rectifying energy, using the same circuit for both tasks, thereby enabling automatic tuning and efficient energy transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a high quality factor (Q) resonant circuit is used in the WPT receiver, then the maximum power delivery capability is improved, but the system becomes highly sensitive to frequency drifts, component variations, and misalignment, degrading stability

Engineering Contradiction:
Improvemaximum power deliveryVSAvoidstability against frequency drift and mismatch
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent implements a dynamic tuning mechanism that continuously adjusts the resonant frequency of the receiver circuit to track the transmitter frequency. The controller modifies switching parameters in real-time based on detected frequency deviations, transforming the static high-Q circuit into a dynamically adaptive system that maintains optimal resonance despite environmental variations and component tolerances.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent employs a feedback control system where the controller monitors the resonant circuit's operating conditions and adjusts the switching parameters accordingly. This closed-loop feedback mechanism detects frequency drift and component variations, then compensates by modifying the switching frequency or duty cycle to maintain optimal power transfer and circuit resonance.

Inventive Principle:
Principle #23Feedback

2Adaptability or versatility

If separate tuning and rectification circuits are used, then the system can handle tuning conditions and power conversion independently, but the overall device complexity increases

Engineering Contradiction:
Improveindependent tuning and rectification controlVSAvoidnumber of separate circuits
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines the tuning function and rectification function into a single integrated circuit structure. The same switching network and controller that perform frequency tuning also execute the rectification process, eliminating the need for separate dedicated tuning circuits and simplifying the overall system architecture while maintaining independent control capabilities.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The controller and switching circuit are designed to perform multiple functions: frequency tuning, resonance optimization, and power rectification. This multi-functional design allows a single circuit element to serve multiple purposes, reducing the total component count and system complexity while preserving the ability to independently control tuning and power conversion operations.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 solution enhances the stability and efficiency of high Q resonant WPT receivers by dynamically adjusting the resonant circuit's reactance, improving power transfer capabilities while maintaining a compact design.

Implementation Method 1

couple the inductor with the resonant circuit to charge the inductor from the resonant voltage during a first portion of time

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

couple the inductor between the resonant tank and the output energy buffer in order to rectify the energy from the resonant tank to the output buffer during a second time portion

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 3

Magnetic resonance wireless power transfer (WPT) has become a reliable technology for contactless power delivery

Methodology Applied
Scientific EffectMagnetic resonance: Resonance

Implementation Method 4

a transmitting coils is energized by an alternating current producing a magnetic flux that is linked to one or more other receiving coils

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3528365B1Turner and rectifier apparatus for wireless power transfer receiver
Publication Date: 2020.07.22 NAPTILUS TECH LAB SL
  • EP3528365B1 patent drawingFigure 1~2
  • EP3528365B1 patent drawingFigure 3~4
  • EP3528365B1 patent drawingFigure 5~6

AI summary

A tuner and rectifier circuit for wireless power transfer receivers is provided using a single inductor and two switching networks. The single inductor is used for energy exchange between the receiver resonant circuit and an output energy buffer network wherein the rectification function is met. The tuning state of the receiver resonant circuit is tracked and the inductor is accordingly coupled with the receiver resonant circuit after an adaptive time period to inject an inductive reactance to the tank for tuning purpose.