Wireless Power Feeder Bi-Directional Current High Voltage

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Solution Overview

Problem

Current wireless power feeding systems using magnetic field resonance type face challenges in safely handling high voltage inputs, particularly due to the risk of damaging switching elements like MOSFETs, and require additional components such as capacitors for resonance circuits, which can lead to power loss and increased costs.

Innovation Solution

A wireless power feeder design that allows bi-directional current flow in the first coil, eliminating the need for a resonance circuit and enabling high voltage application directly to the coil, with a power transmission control circuit that includes a bridge rectification circuit and capacitors to charge AC power, allowing for high input voltage utilization and voltage adjustment through winding ratios and inductance settings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a resonance circuit with capacitor is used to protect MOSFETs from high voltage, then switching elements are protected, but device complexity and power loss increase

Engineering Contradiction:
Improveprotection of switching elementsVSAvoidadditional capacitor components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent removes the capacitor component from the resonance circuit, extracting the harmful element that causes complexity and power loss. The circuit is redesigned to function without the capacitor, eliminating the technical contradiction between protection and complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the circuit parameters by removing the capacitor and adjusting the MOSFET switching timing to achieve safe operation with high voltage input without requiring additional protective components, thereby reducing device complexity while maintaining reliability.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a resonance circuit with capacitor is used, then voltage control is achieved, but power loss and cost increase

Engineering Contradiction:
Improvevoltage controlVSAvoidpower loss
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The capacitor is extracted from the circuit, eliminating the source of power loss associated with resonance circuits. The patent achieves voltage control through alternative means that do not require energy-dissipating components.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The circuit is designed to utilize the inherent properties of the coil and MOSFET switching to achieve voltage control without requiring additional active components like capacitors, making the system more efficient and self-sufficient.

Inventive Principle:
Principle #25Self-service

3Power

If commercial power supply with high voltage is used, then power transmission capability increases, but switching elements may be damaged

Engineering Contradiction:
Improvepower transmission capabilityVSAvoidswitching element safety
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent employs dynamic MOSFET switching control to manage the high voltage from commercial power supplies. By dynamically adjusting the switching timing and duration, the circuit can safely handle high voltage inputs while maintaining power transmission capability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The MOSFETs are switched periodically with controlled duty cycles to manage the high voltage input. This periodic switching action allows the circuit to process high voltage commercially available power supplies while protecting the switching elements through controlled exposure times.

Inventive Principle:
Principle #19Periodic action

4Reliability

If AC adapter is used to reduce voltage, then switching elements are protected, but power loss and cost increase

Engineering Contradiction:
Improveswitching element protectionVSAvoidpower loss
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent eliminates the need for external voltage reduction devices like AC adapters by redesigning the circuit to directly handle high voltage inputs. This removes the source of power loss associated with voltage conversion while maintaining switching element protection.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The circuit performs its own voltage management functionally through MOSFET switching control, eliminating the need for separate voltage reduction components. The system serves itself by handling high voltage directly without external intervention.

Inventive Principle:
Principle #25Self-service

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 safe wireless power feeding even with high voltage inputs, reducing the risk of switching element damage and eliminating the need for additional components like capacitors, thus enhancing power transmission efficiency and adaptability to varying commercial power supply voltages.

Implementation Method 1

When AC power is fed to the exciting coil, current also flows in the feeding coil according to the principle of electromagnetic induction

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

When the feeding coil generates a magnetic field to cause the feeding coil and receiving coil to magnetically resonate, large current flows in the receiving coil

Methodology Applied
Scientific EffectMagnetic field resonance: Resonance

Implementation Method 3

a power transmission control circuit that includes a bridge rectification circuit and capacitors to charge AC power

Methodology Applied
Scientific EffectRectification:

Data Source

PatentEP2309620B1Wireless power feeder and wireless power transmission system
Publication Date: 2022.04.13 TDK CORP
  • EP2309620B1 patent drawingFigure 1
  • EP2309620B1 patent drawingFigure 2
  • EP2309620B1 patent drawingFigure 3

AI summary

Power is fed from a feeding coil L2 to a receiving coil L3 by magnetic resonance. An oscillator 202 alternately turns ON/OFF switching transistors Q1 and Q2 to cause AC current IS of drive frequency fo to flow in a transformer T2 primary coil Lb. The AC current IS causes AC current I1 to flow in an exciting coil L1 and causes AC current I2 to flow in the feeding coil L2.