LC Oscillating Circuit Foreign Object Detection
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Solution Overview
Problem
Inductive power transfer systems face challenges in detecting foreign objects made of metal, which can cause power losses and heating issues, posing safety risks and potential fires due to induced currents.
Innovation Solution
An object detection system utilizing an LC oscillating circuit with a driving circuit that generates an alternating current voltage matching the resonant frequency, allowing for sensitive detection of foreign objects by measuring changes in input power and resonant frequency shifts, independent of the power transfer field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an LC oscillating circuit is used for foreign object detection in an inductive power transfer system, then detection sensitivity is improved, but the detection reliability deteriorates due to interference from the power transfer field
Solution Approach 1:
The system separates the detection function from the power transfer function by using distinct circuits: an LC oscillating circuit for detection and a primary winding for power transfer. This segmentation allows independent optimization of each function and prevents interference between them.
Solution Approach 2:
The patent introduces a detection winding as an intermediary element that couples to the LC oscillating circuit. This intermediary allows the detection system to sense foreign objects without directly interacting with the powerful electromagnetic field generated by the primary winding, thus maintaining sensitivity while avoiding interference.
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 system provides robust, reliable, and sensitive detection of foreign objects, minimizing false positives and reducing installation space, while ensuring safe operation by decoupling detection sensitivity from environmental conditions and power transfer field effects.
Implementation Method 1
a detection winding can be part of a LC oscillating circuit
Implementation Method 2
The varying magnetic field generated by the primary unit and a secondary unit may induce current in the foreign objects made of metal
Implementation Method 3
The primary winding structure generates a primary electromagnetic field which is received by a vehicle-sided secondary unit
Implementation Method 4
This current can e.g. be generated at least partially by the mutual induction between the primary winding structure and the secondary winding structure
Data Source
AI summary
An object detection system for an inductive power transfer system, for transferring power to a vehicle on a surface of a route. The object detection system comprises at least one LC oscillating circuit and at least one driving circuit. An input side of the driving circuit is connected to a power supply circuit and an output side of the driving circuit is connected to the at least one LC oscillating circuit. The driving circuit provides an alternating current voltage to the at least one oscillating circuit. The object detection system comprises at least one means for capturing an input power to the driving circuit provided by the power supply circuit and the object detection system comprises at least one detection means for detecting a foreign object depending on the captured input power.