Variable Frequency Non-Contact Power Supply for Efficiency

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Solution Overview

Problem

Conventional non-contact power supplying devices experience reduced efficiency due to variations in the coupling state between the power-feeding and power-receiving sides, as the input frequency of the oscillator is fixed, leading to inefficiencies in electric power transmission.

Innovation Solution

The frequency of AC power is adjusted based on the impedance viewed from the power-feeding side within a predetermined range, using a frequency-variable unit to detect and set the optimal frequency for high power-transmission efficiency, even if the coupling state changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the input frequency of the oscillator is fixed at a common resonant frequency, then the system is simple to operate, but the power transmission efficiency is reduced when the coupling state between power-feeding and power-receiving sides varies

Engineering Contradiction:
Improvefrequency control simplicityVSAvoidpower transmission efficiency
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The patent applies dynamics by transitioning from a fixed frequency oscillator to a variable frequency oscillator that dynamically adjusts its operating frequency based on real-time impedance detection. The control unit continuously monitors impedance and modifies the oscillator frequency to maintain optimal coupling conditions, thereby resolving the contradiction between operational simplicity and transmission efficiency.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements parameter changes by varying the frequency parameter of the oscillator in response to impedance changes. The control unit detects impedance variations and adjusts the frequency parameter accordingly, allowing the system to adapt to different coupling states and maintain high power transmission efficiency across varying operating conditions.

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If the frequency of AC power is adjusted based on impedance detection, then the power transmission efficiency is maintained, but the device complexity increases due to additional frequency control mechanisms

Engineering Contradiction:
Improvepower transmission efficiencyVSAvoidfrequency control structure
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent applies universality by designing the control unit to perform multiple functions: impedance detection, frequency analysis, and oscillator control. This multi-functional approach consolidates what could be separate complex subsystems into a single integrated unit, maintaining power transmission efficiency while minimizing the increase in overall device complexity.

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

Solution Approach 2:

The patent implements feedback by creating a closed-loop control system where the control unit continuously monitors impedance, compares it to optimal values, and adjusts the oscillator frequency accordingly. This feedback mechanism enables automatic adaptation to coupling state changes without requiring complex manual intervention or additional detection structures on the power-receiving side.

Inventive Principle:
Principle #23Feedback

3Device complexity

If a fixed resonant frequency is used for both power-feeding and power-receiving sides, then the system configuration is simple, but the transmission distance is limited due to coupling state variations

Engineering Contradiction:
Improvesystem configurationVSAvoidpower transmission distance
Core Design Contradiction:
Device complexityVSLength of moving object

Solution Approach 1:

The patent applies dynamics by enabling the power-feeding side frequency to dynamically track optimal coupling conditions across varying distances. The variable frequency capability allows the system to maintain resonance and high transmission efficiency over extended distances by adapting to changes in coupling state, thereby extending the effective power transmission range without significantly complicating the system configuration.

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

This approach maintains high power-transmission efficiency and extends the distance over which power can be transmitted effectively, without requiring additional detection structures on the power-receiving side, by dynamically adjusting the frequency in response to changes in the coupling state.

Implementation Method 1

a power-feeding resonator 12 which generates a magnetic field from the alternating-current power inputted by the oscillator 11

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

electric power is transmitted with the non-contact state by using a technique of electromagnetically resonating a power-feeding side and a power-receiving side at a common resonant frequency

Methodology Applied
Scientific EffectElectromagnetic resonance: Resonance

Data Source

PatentEP2405556B1Non-contact power supplying device and non-contact power supplying method
Publication Date: 2019.01.23 NISSAN MOTOR CO LTD
  • EP2405556B1 patent drawingFigure 1A
  • EP2405556B1 patent drawingFigure 1B
  • EP2405556B1 patent drawingFigure 2A

AI summary

A non-contact power supplying device includes a power-receiving resonating means set to have a predetermined resonant frequency; a power-feeding resonating means set to have a resonance frequency equal to the predetermined resonant frequency; an oscillating means configured to input an alternating-current power into the power-feeding resonating means; an impedance detecting means configured to detect impedance within a predetermined frequency range as viewed from a power-feeding side; and a frequency-variable means configured to set a frequency of the alternating-current power. The oscillating means is configured to supply electric power to the power-receiving resonating means by producing a resonance between the power-receiving resonating means and the power-feeding resonating means. The frequency-variable means is configured to set the frequency of the alternating-current power in accordance with a value of the impedance detected by the impedance detecting means within the predetermined frequency range.