Resonance Matching Circuit Timing Adjustment for Inverter Efficiency

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Solution Overview

Problem

Voltage type inverter circuits used in contactless charging systems face efficiency drops when connected to parallel resonance circuits, as they fail to perform zero-cross operations, leading to decreased transmission efficiency and potential overload or no load issues due to environmental changes.

Innovation Solution

A resonance matching circuit is designed with a timing adjustment circuit and parallel transformer devices, which includes series capacitive elements and adjustment coils to maintain efficiency by adjusting resonance frequencies and enabling zero-cross operations, ensuring the inverter circuit operates effectively even with parallel resonance circuits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a parallel resonance circuit is connected to the voltage type inverter circuit, then the electric field coupling unit is less affected by environmental changes, but the inverter circuit cannot perform zero-cross operation and transmission efficiency decreases

Engineering Contradiction:
Improvestability against environmental changesVSAvoidtransmission efficiency
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

A series resonance circuit is introduced as an intermediary between the voltage type inverter circuit and the parallel resonance circuit. This intermediate series resonance circuit enables the inverter to perform zero-cross operations while the parallel resonance circuit maintains stability against environmental changes, thus resolving the contradiction between reliability and energy loss.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The resonance circuit is segmented into two distinct parts: a series resonance circuit connected to the inverter and a parallel resonance circuit connected to the load. This segmentation allows each part to fulfill its specific function - the series part enables zero-cross switching for efficiency, while the parallel part provides environmental stability.

Inventive Principle:
Principle #1Segmentation

2Loss of energy

If a series resonance circuit is provided on the load side of the voltage type inverter circuit, then zero-cross operation can be performed, but the electric field coupling unit is easily affected by environmental changes

Engineering Contradiction:
Improvetransmission efficiencyVSAvoidstability against environmental changes
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The resonance circuit is divided into two functional segments: a series resonance circuit for enabling zero-cross operations and a parallel resonance circuit for providing environmental stability. This segmentation allows both contradictory requirements to be satisfied simultaneously.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Both series and parallel resonance circuits are merged into a single resonance matching system, combining the advantages of zero-cross capability from the series circuit with the environmental stability from the parallel circuit.

Inventive Principle:
Principle #5Merging (Combining)

3Adaptability or versatility

If the state of contact between the electric device and the electric field coupling unit is inappropriate, then no load may be caused, but if the electric device has a very large amount of charge, an overload may be caused

Engineering Contradiction:
Improveadaptability to different contact statesVSAvoidprotection against no load and overload
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The control unit monitors the operational state of the inverter circuit and dynamically adjusts the switching timing based on feedback signals. This feedback mechanism enables the system to adapt to different contact states and prevents both no-load and overload conditions by optimizing the zero-cross switching timing.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The switching timing of the inverter is made dynamic rather than fixed, allowing the system to adapt its operation based on real-time conditions. This dynamic adjustment enables the system to handle varying contact states and charge levels safely.

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 resonance matching circuit maintains transmission efficiency of the voltage type inverter circuit when connected to a parallel resonance circuit, preventing efficiency drops and ensuring stable operation across varying loads, with experimental results showing improved efficiency up to 93.1% compared to direct connections.

Implementation Method 1

a resonance matching circuit is designed with a timing adjustment circuit and parallel transformer devices, which includes series capacitive elements and adjustment coils to maintain efficiency by adjusting resonance frequencies

Methodology Applied
Scientific EffectResonance: Resonance

Implementation Method 2

parallel transformer devices, which includes series capacitive elements and adjustment coils

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3771070B1Resonant rectifier circuit
Publication Date: 2022.07.20 SUMIDA CORP
  • EP3771070B1 patent drawingFigure 1
  • EP3771070B1 patent drawingFigure 2

AI summary

An object of the present invention is to provide a resonance matching circuit that does not decrease transmission efficiency of a voltage type inverter circuit even when the resonance matching circuit is connected to a parallel resonance circuit. A resonance matching circuit 1 according to the present invention used in a power supply system 100 that supplies electric power by an electric field coupling method. The resonance matching circuit 1 includes an inverter circuit 10 that functions as a voltage source, parallel transformer devices 30 and 40 that are connected in parallel to the inverter circuit 10 and transmit a current supplied from the inverter circuit 10, and a timing adjustment circuit 20 that is located between the inverter circuit 10 and the parallel transformer devices 30 and 40 and adjusts an input timing of a pulse current supplied by the inverter circuit 10.