Interleaved Rectifier Impedance Matching for Wireless Power

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Solution Overview

Problem

Wireless power systems face challenges in efficiently transmitting power due to the wide range of impedances and harmonic content, which affects the matching of impedance and efficiency in wireless power receivers.

Innovation Solution

The implementation of an interleaved rectifier with imbalanced reactive components in the impedance matching network to mitigate impedance mismatch caused by harmonic content, reducing peak current and thermal issues, and optimizing power transfer across a wide range of battery voltages.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a conventional rectifier is used in a wireless power receiver, then the system can operate with a simple structure, but the impedance mismatch caused by harmonic content reduces power transfer efficiency

Engineering Contradiction:
Improvepower transfer efficiencyVSAvoidrectifier structure complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The rectifier is divided into multiple parallel rectifying circuits (first rectifying circuit, second rectifying circuit, etc.) that process different harmonic components of the received wireless power signal. Each rectifying circuit is tuned to a specific frequency (fundamental frequency, third harmonic frequency, fifth harmonic frequency), allowing selective and efficient rectification of different frequency components while maintaining overall system efficiency.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If the impedance matching network is designed for a single frequency, then the circuit design is simplified, but the wide range of battery voltages causes impedance mismatch and reduces efficiency

Engineering Contradiction:
Improvebattery voltage range adaptationVSAvoidimpedance matching network complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The impedance matching network is designed to handle multiple frequency components (fundamental frequency and harmonic frequencies) simultaneously through parallel resonant circuits. Each resonant circuit is tuned to a specific frequency, enabling the network to adapt to a wide range of battery voltages and loading conditions while maintaining efficient power transfer across varying operating conditions.

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

3Power

If high power is transmitted to handle large voltage ranges, then the power transfer capability is improved, but thermal issues and component stress increase

Engineering Contradiction:
Improvepower transfer capabilityVSAvoidthermal issues
Core Design Contradiction:
PowerVSTemperature

Solution Approach 1:

The power transfer task is segmented across multiple parallel rectifying circuits operating at different frequencies. By distributing the power processing across multiple circuits rather than using a single high-power circuit, the thermal load and component stress are reduced while maintaining the overall power transfer capability needed for large battery voltage ranges.

Inventive Principle:
Principle #1Segmentation

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 configuration leads to improved efficiency, reduced stress on components, and a smaller footprint by balancing currents and impedance, ensuring efficient power transfer and reduced thermal issues across varying power levels and battery voltages.

Implementation Method 1

a multi-frequency resonant circuit having a first resonant frequency and a second resonant frequency, the second resonant frequency being different than the first resonant frequency, the multi-frequency resonant circuit to receive energy having a first frequency and a second frequency, the second frequency being different than the first frequency

Methodology Applied
Scientific EffectElectromagnetic Induction: Electromagnetic Induction

Implementation Method 2

an interleaved rectifier including a first rectifying circuit and a second rectifying circuit, the first rectifying circuit to receive the energy having the first frequency from the multi-frequency resonant circuit and to provide first rectified energy, the second rectifying circuit to receive the energy having the second frequency from the multi-frequency resonant circuit and to provide second rectified energy

Methodology Applied
Scientific EffectRectification: Diode

Data Source

PatentEP3504769B1Wireless power transfer systems having interleaved rectifiers
Publication Date: 2020.12.16 WITRICITY CORP
  • EP3504769B1 patent drawingFigure 1~2
  • EP3504769B1 patent drawingFigure 3~4
  • EP3504769B1 patent drawingFigure 5A~5B

AI summary

A wireless power receiver (300) is coupled to an impedance matching network (C3A', C3A'', C3B', C3B''), the impedance matching network having a first output node (N3) and a second output node (N4). Coupled to the first output node (N3) is a first branch having a component (L4A, C4A) with a first positive reactance (X4A) and a second branch having a component (L4B, C4B) with a first negative reactance (X4B), wherein an absolute value of the first positive reactance (X4A) is different from an absolute value of the first negative reactance (X4B), and coupled to the second output node (N4) is a third branch having a component (L4C, C4C) with a second positive reactance (X4C) and a fourth branch having a component (L4D, C4D) with a second negative reactance (X4D), wherein an absolute value of the second positive reactance (X4C) is different from an absolute value of the second negative reactance (X4D).