Wireless Power Receiver Control for Variable Coil Gaps
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Solution Overview
Problem
Existing non-contact power transmission systems face challenges in maintaining appropriate power control and abnormality detection due to changes in the gap between power transmission and reception coils, which can be influenced by vehicle size, tire replacement, suspension changes, and loading capacity, affecting power suppliability and detection accuracy.
Innovation Solution
A non-contact power transmission system that includes a power reception unit, a power conversion unit, a current sensor, and a control device to detect mutual inductance and adjust power conversion based on current output, allowing for appropriate power control and abnormality detection by restricting output when the mutual inductance falls below a threshold, and implementing short-circuiting to manage coil intervals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the gap between power transmission side coil and power reception side coil changes due to vehicle variations, then power suppliability changes, but abnormality detection becomes difficult
Solution Approach 1:
The system measures the actual mutual inductance between the coils and feeds this information back to the control device. Based on this feedback, the control device adjusts the power transmission level adaptively, allowing reliable operation across varying coil gaps while maintaining accurate abnormality detection through continuous monitoring of the mutual inductance values.
2Loss of energy
If mechanical adjustment of relative position between coils is used to control coupling coefficient, then transmission efficiency is adjusted, but system complexity increases
Solution Approach 1:
The patent replaces mechanical adjustment mechanisms with electrical control. The control device adjusts the transmission efficiency by controlling the power transmission level electrically based on measured mutual inductance, eliminating the need for mechanical position adjustment while achieving the same goal of optimizing transmission efficiency.
3Ease of operation
If power transmission is performed without mutual inductance measurement, then system operation is simple, but appropriate power control cannot be performed
Solution Approach 1:
The system performs self-diagnosis by automatically measuring its own mutual inductance and using this information for adaptive power control. This self-service approach maintains operational simplicity while achieving precise power control, as the system autonomously adjusts its operation based on real-time measurements without requiring complex external control mechanisms.
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 control and abnormality detection even with varying coil gaps, ensuring efficient power transmission and reducing current flow by short-circuiting coils when necessary, thus maintaining system stability and efficiency.
Implementation Method 1
a power reception side coil receiving AC power transmitted from a power transmission side coil in a non-contact manner
Implementation Method 2
acquires a mutual inductance between the power transmission side coil and the power reception side coil on the basis of a detection value of a current
Data Source
AI summary
A non-contact power transmission system includes a power reception unit, a received power conversion unit, a current sensor, and a control device. The power reception unit includes a secondary side coil for receiving AC power transmitted in a non-contact manner from a primary side coil of a power transmission device. The received power conversion unit converts AC power received by the power reception unit into DC power. The current sensor detects a current output from the received power conversion unit. The control device acquires a mutual inductance between the primary side coil and the secondary side coil on the basis of a detection value of the current output from the current sensor and controls the received power conversion unit in accordance with the mutual inductance.