Inductive Power Transfer Distance Sensing for Axial Offset Detection

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Solution Overview

Problem

Existing inductive power transmission systems face challenges in accurately determining the axial offset between the transmitter and receiver, which affects the estimation of power transmission, and are prone to inefficiencies due to foreign objects that can cause heating and safety hazards.

Innovation Solution

A system and method that utilize a control unit to record secondary power data and frequency parameters to determine the actual distance between the primary and secondary devices using a distance characteristic field, which includes reference data correlations, allowing for precise distance determination and detection of foreign objects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If inductive power transmission is performed without accurate distance determination, then power transmission can occur, but power transmission accuracy deteriorates due to unknown axial offset

Engineering Contradiction:

Improvedistance determination accuracyVSAvoidpower transmission accuracy

Core Design Contradiction:

Measurement precisionVSPower

Solution Approach 1:

The system measures secondary power data during operation and uses this feedback to determine the actual distance between primary and secondary devices. The control unit adjusts power transmission based on the determined distance to maintain accurate power delivery despite varying axial offsets.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system changes operational parameters (frequency and power) to determine distance characteristics. By measuring secondary power data at different frequency parameters and comparing with reference data, the system calculates the actual distance and adjusts transmission accordingly.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If foreign objects are present in the electromagnetic field, then power transmission continues, but harmful effects increase due to heating of foreign objects

Engineering Contradiction:

Improvepower transmission continuityVSAvoidheating of foreign objects

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The system uses the presence of foreign objects, which alter the electromagnetic field and secondary power characteristics, as a detection mechanism. By analyzing changes in secondary power data and distance characteristics, the system identifies foreign objects and can adjust or stop transmission to prevent harmful heating.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Measurement precision

If distance determination is performed using reference data correlations, then distance measurement precision improves, but device complexity increases due to control unit processing requirements

Engineering Contradiction:

Improvedistance measurement accuracyVSAvoidcontrol unit complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

Reference data correlations are pre-established and stored in the control unit before operation. During power transmission, the system simply compares measured secondary power data against these pre-stored reference correlations to determine distance, avoiding complex real-time calculations and reducing processing complexity.

Inventive Principle:

Principle #10Preliminary action

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 accurate power transmission by accounting for axial offsets and foreign objects, enhancing efficiency and safety by minimizing heating risks and reducing maintenance needs.

Implementation Method 1

the primary device is arranged and designed to inductively transmit power, via a primary oscillating circuit, to a secondary oscillating circuit of the secondary device

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS20260095070A1System for inductively transmitting power from a primary device to a secondary device, primary device, and method for operating such a system

Publication Date: 2026.04.02 TURCK HOLDING GMBH

AI summary

An inductive power transmission system is provided, comprising a primary device; a secondary device; and a control unit; wherein the primary device is arranged and designed to inductively transmit power, via a primary oscillating circuit, to a secondary oscillating circuit of the secondary device during power transmission; wherein the control unit is designed to record secondary power data of the secondary device and a frequency parameter of the primary device; wherein the control unit is designed to determine an actual distance between the primary device and the secondary device based on a distance characteristic field, the recorded secondary power data and the recorded frequency parameter; and wherein the distance characteristic field includes reference secondary power data as a function of reference frequency parameters and as a function of reference distances.