Inductive Charging Metal Object Detection via Hybrid Sensor Modes
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Solution Overview
Problem
Conventional metal object detection methods for inductive vehicle charging are hindered by strong magnetic fields during energy transmission, leading to inefficient detection and increased charging time due to the need for frequent switching and additional losses.
Innovation Solution
A hybrid approach combining passive and active metal object detection methods, allowing for reliable detection both during and outside energy transmission, using a sensor coil structure with both passive electronic evaluation and active electronic sensor systems, and a control facility to switch between modes, reducing complexity and hardware requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If active metal object detection is performed during energy transmission, then detection capability is improved, but the strong magnetic field causes detection inaccuracy and requires frequent switching
Solution Approach 1:
The system dynamically switches between passive and active detection modes based on whether energy transmission is occurring. During energy transmission, passive detection is used to avoid magnetic field interference. When energy transmission stops, active detection is activated for more accurate metal object detection. This dynamic mode switching resolves the contradiction by adapting the detection method to the operational state.
Solution Approach 2:
The control facility acts as an intermediary that coordinates between the energy transmission system and the detection system. It manages the timing and mode of detection operations, ensuring that passive detection occurs during energy transmission while active detection occurs during idle periods, thereby resolving the conflict between detection accuracy and magnetic field interference.
2Measurement precision
If active metal object detection is performed during energy transmission, then detection capability is improved, but additional losses and charging time increase
Solution Approach 1:
The system performs active metal object detection periodically during idle periods when energy transmission is not occurring. This periodic active detection complements the continuous passive detection during energy transmission, maintaining safety without interrupting the charging process and avoiding additional charging time.
3Measurement precision
If complex field characterization is used for metal object detection, then detection precision is improved, but device complexity increases
Solution Approach 1:
The detection system is segmented into two distinct modes: passive detection during energy transmission and active detection during idle periods. Each mode uses appropriately simplified characterization methods suited to its operational context, avoiding the need for complex full-field characterization in both modes simultaneously and thereby reducing overall system complexity.
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 precise and efficient metal object detection without the need for complex field characterization, minimizing environmental influences and maintaining low additional hardware requirements, thus ensuring safe and efficient energy transmission.
Implementation Method 1
The primary coil is supplied with an alternating current and subsequently transmits a high frequency magnetic alternating field. This magnetic alternating field generates a corresponding alternating current in a receiver coil
Implementation Method 2
a sensor coil structure having a number of sensor coils; a passive electronic evaluation system, which is configured so as in the passive detection mode to evaluate a current that is induced in the sensor coil structure
Implementation Method 3
an active electronic sensor system, which is configured so as in the active detection mode to generate a magnetic sensor field for an active MOD procedure
Implementation Method 4
The magnetic fields that occur in the air gap during the transmission procedure are suitable for inducing electrical eddy currents in any metal or electrical conductive objects that are located in the air gap. Ohmic losses cause these so-called foreign objects to heat up
Data Source
AI summary
The invention relates to an inductive charging device for a vehicle and to a method for monitoring an inductive charging device for a vehicle, wherein a metal object is detected in each case. The method has the steps of: carrying out a passive metal object detection, MOD, while a battery of a vehicle (1) is inductively charged by generating an electromagnetic field in order to induce a charge current (I2) in a receiving coil structure (2) of the vehicle (1); and carrying out an active MOD at points in time at which no inductive charging process is being carried out.