Arc Segment Eddy Current Coils for Wireless Power Alignment Error Detection
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Solution Overview
Problem
Axial misalignment of resonant inductive wireless power transfer coils significantly reduces magnetic coupling and efficiency, making it difficult to achieve precise alignment for efficient power transfer, particularly in applications like electric vehicle charging.
Innovation Solution
The introduction of arc segment eddy current coils superimposed on the primary induction coil, connected to a bridge rectifier and switching elements, which communicate through a sequencer to detect and correct alignment errors by reducing magnetic flux variations, allowing for precise determination of alignment error magnitude and direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If resonant inductive wireless power transfer is implemented, then power transmission capability is improved, but coil alignment precision deteriorates
Solution Approach 1:
The detection system is segmented into multiple arc segment eddy current coils arranged in different orientations (first set in first orientation, second set in second orientation). This segmentation allows independent detection of alignment errors in different directions, enabling precise identification of misalignment without affecting the overall power transmission capability of the resonant inductive system.
Solution Approach 2:
Arc segment eddy current coils are introduced as intermediary detection elements between the primary and secondary coils. These intermediary coils detect magnetic flux variations caused by misalignment and convert them into measurable signals, enabling precise alignment detection without directly interfering with the main power transfer path.
2Measurement precision
If arc segment eddy current coils are added for alignment detection, then alignment detection precision is improved, but device complexity increases
Solution Approach 1:
The detection function is merged with the existing resonant inductive power transfer system by superimposing arc segment eddy current coils on the primary coil structure. The bridge rectifiers and switching elements are integrated into the existing circuit architecture, allowing alignment detection to be performed using the same physical platform without requiring completely separate detection hardware.
Solution Approach 2:
The primary coil serves multiple functions: it acts as both the power transmission coil and the structural base for mounting the arc segment eddy current coils. The system simultaneously performs wireless power transfer and alignment detection, eliminating the need for separate dedicated detection hardware and reducing overall device complexity.
3Measurement precision
If sequential switching of switching elements is used for detection, then detection accuracy is improved, but detection time increases
Solution Approach 1:
The switching elements are activated in a sequential periodic manner, with each switching element being turned on for a predetermined time period in turn. This periodic activation allows the system to measure magnetic flux variations from different arc segment coils at different time intervals, enabling accurate determination of alignment error magnitude and direction through time-based differentiation of the periodic signals.
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
This solution enables accurate detection and correction of axial misalignment, ensuring efficient wireless power transfer by minimizing magnetic flux variations and providing clear alignment feedback to operators, thereby enhancing the efficiency and reliability of resonant inductive power transfer systems.
Implementation Method 1
arc segment eddy current coils superimposed on the primary induction coil
Implementation Method 2
Each arc segment eddy current coil connects to a bridge rectifier
Implementation Method 3
resonant inductive wireless power transfer
Implementation Method 4
Magnetic coupling between the primary induction coil and a secondary induction coil transfers energy
Implementation Method 5
Resonance applied to the primary induction coil increases primary side inductor current producing a corresponding increase in the magnetic flux in the secondary inductor current
Data Source
AI summary
A method for detecting induction coil alignment error in resonant induction wireless power apparatus includes an eddy current coil array superimposed upon the primary induction coil, a switching device for each eddy current coil, a voltage detector such as a low power rectifier connected to the secondary induction coil, an analog-to-digital converter, primary and secondary side micro-controllers, and, in a vehicle charging embodiment, a vehicle operator interface. During coil alignment, the primary side induction coil operates at low power. Eddy current flows in an eddy current coil only if the associated switching device is switched on.