Inductive Power Transmission Device with Control Circuit for No-Load Loss Reduction

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Solution Overview

Problem

Inductive battery chargers experience high energy losses during no-load conditions, limiting their efficiency and compliance with energy consumption regulations, and are typically limited to specific supply voltages, restricting their use across different markets.

Innovation Solution

A power transmission device with a control circuit that monitors a resonant circuit to detect the presence of a target device, enabling zero voltage switching for efficient energy transfer during load conditions and minimizing amplification during no-load conditions, while a dimming circuit converts a wide range of input voltages to a constant operating voltage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the resonant circuit operates continuously to enable inductive energy transfer, then energy transfer capability is maintained, but energy losses increase significantly under no-load conditions

Engineering Contradiction:
Improveenergy losses under no-load conditionsVSAvoidenergy transfer capability
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent implements periodic detection cycles where the control circuit alternates between detection phases (when no target is present) and charging phases (when a target is detected). During detection phases, the resonant circuit operates at reduced power or in standby mode, while during charging phases it operates at full power. This periodic operation resolves the contradiction by maintaining energy transfer capability when needed while minimizing energy losses during no-load conditions.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system dynamically adjusts the operating state of the resonant circuit based on real-time detection of target device presence. The control circuit monitors coupling conditions and transitions the resonant circuit between different operational modes (standby, detection, charging). This dynamic adaptation allows the system to maintain reliability when targets are present while reducing energy losses when targets are absent.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If the power transmission device is designed for a specific supply voltage, then circuit design is simplified, but adaptability to different markets and applications is limited

Engineering Contradiction:
Improveoperating voltage rangeVSAvoidcircuit design complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent designs the power transmission device with a universal power input stage that can accept a wide range of supply voltages (e.g., 90-264 VAC). The circuit incorporates voltage detection and adaptive control mechanisms that automatically adjust operating parameters based on the detected input voltage. This universal design approach enables the device to adapt to different market voltage standards without requiring voltage-specific model variations, thereby improving adaptability while managing complexity through integrated control.

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

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 solution significantly reduces energy losses under no-load conditions and allows the device to operate across a wide range of input voltages, enhancing efficiency and compliance with energy regulations.

Implementation Method 1

a resonant circuit connected to the first stage and adapted to generate an oscillating voltage from the operating voltage so as to generate a magnetic field for contactless transfer of energy

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a magnetic coupling between the base part and the mobile part can be obtained so as to allow energy transfer from the base part to the mobile part

Methodology Applied
Scientific EffectMagnetic coupling: Electromagnetic Induction

Data Source

PatentEP2808975B1Inductive power transmission device
Publication Date: 2018.09.19 FRIWO GERAETEBAU GMBH
  • EP2808975B1 patent drawingFigure 1(a)~1(b)
  • EP2808975B1 patent drawingFigure 2
  • EP2808975B1 patent drawingFigure 3

AI summary

The present invention provides a power transmission device for inductive energy transfer. The power transmission device comprises a first stage (210) adapted to be connected to a supply input voltage and adapted to convert the supply input voltage to an operating voltage. The power transmission device further includes a second stage (220) comprising a resonant circuit (221) connected to the first stage and adapted to generate an oscillating voltage from the operating voltage so as to generate a magnetic field for inductive transfer of energy from the power transmission device to a target device. A control circuit (230) is connected to the second stage. The control circuit is adapted to detect a parameter value of the second stage and is adapted to start or stop amplification of the resonant circuit based on the detected parameter value.