Variable Reactor Inductance Control for Wireless Power Misalignment

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Solution Overview

Problem

When misalignment between power-transmitting and power-receiving coils occurs, existing wireless power-supplying systems face challenges in supplying desired power without exceeding the withstanding voltage of elements in the voltage converter or inverter circuit, leading to inefficient power transfer.

Innovation Solution

A wireless power-supplying system that includes a variable reactor in the filter circuit, switchable by a switching element, which adjusts inductance or capacitance to maintain optimal power transfer and prevent voltage exceeding the withstanding limits, using a control unit to monitor and adjust the reactor settings based on received power and voltage levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If voltage is stepped up using the chopper circuit to supply desired power when coil misalignment occurs, then power supply capability is improved, but the voltage may exceed the withstanding voltage of the capacitor in the voltage converter

Engineering Contradiction:
Improvepower supply capabilityVSAvoidvoltage withstanding limit
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent applies dynamics by making the inductance value changeable during operation. The inductance value is dynamically adjusted based on the coupling state between coils, allowing the system to adapt to misalignment conditions while maintaining safe voltage levels. The control unit changes the inductance value of the reactor in response to detected voltage conditions, enabling continuous operation without exceeding component limits.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements parameter changes by modifying the inductance value of the reactor based on operating conditions. When the coupling state deteriorates or voltage approaches the withstanding limit, the control unit adjusts the inductance parameter to optimize power transfer while preventing voltage overload. This parameter adjustment resolves the contradiction between maintaining power supply capability and staying within safe voltage limits.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If the inductance value of the reactor is made changeable to improve power transfer under misalignment, then power supply flexibility is improved, but device complexity increases

Engineering Contradiction:
Improvepower transfer adaptabilityVSAvoidcircuit configuration complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent introduces an intermediary element - the control unit - that manages the complexity of variable inductance control. Rather than requiring complex hardware modifications to achieve variable inductance, the control unit serves as an intelligent intermediary that adjusts the reactor's inductance value based on feedback from voltage and coupling state detection. This centralized control approach simplifies the overall system architecture while enabling adaptive power transfer.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent implements feedback control where the control unit continuously monitors the voltage across the capacitor and the coupling state between coils. Based on this feedback information, the control unit automatically adjusts the inductance value of the reactor to maintain optimal power transfer. This closed-loop feedback mechanism enables adaptive control without requiring complex manual intervention or overly sophisticated hardware designs.

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

Enables efficient power delivery to the power-receiving device without exceeding the withstanding voltage of the voltage converter or inverter circuit elements, even with significant coil misalignment, ensuring reliable and targeted power transfer.

Implementation Method 1

a wireless power-supplying system that supplies power from a power-transmitting device including a power-transmitting coil to a power-receiving device including a power-receiving coil using magnetism

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

the element which is disposed from the receiving-side pad to the filter circuit is a reactor in the filter circuit, and the reactor is a variable reactor

Methodology Applied
Scientific EffectInductance adjustment: Inductor

Data Source

PatentEP3157118B1Power-transmitting device and contactless power-supplying system
Publication Date: 2021.03.24 IHI CORP
  • EP3157118B1 patent drawingFigure 1
  • EP3157118B1 patent drawingFigure 2
  • EP3157118B1 patent drawingFigure 3~4

AI summary

When a voltage across an element of a voltage converter or an inverter circuit (3) has reached an upper limit of a withstanding voltage of the element and it is determined that received power of a power-receiving device (R) has not reached a target value, an instruction for changing at least one of inductance and capacitance of an element which is disposed from a receiving-side pad to a filter circuit in the power-receiving device (R) is transmitted from a power-transmitting device (S) to the power-receiving device (R) so as to satisfy a condition that the received power approaches a target value.