Power Transmission Control Device Adaptive Threshold Detection
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Solution Overview
Problem
Existing non-contact power transmission systems face challenges in accurately detecting data and determining the presence of foreign objects or detachment due to variations in element constants such as power supply voltage or coil inductance, leading to inconsistent threshold voltages and incorrect detection.
Innovation Solution
A power transmission control device that includes an amplitude detection circuit, A/D conversion circuit, and control circuit, which performs A/D conversion of detected voltage after a given period has expired from when the voltage exceeds a provisional voltage, using digital data to determine reference threshold voltages for data detection, foreign object detection, and detachment detection, thereby stabilizing the detection process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed threshold voltage is used to detect data transmitted by load modulation, then the detection process is simple, but the detection accuracy deteriorates due to variations in element constants such as power supply voltage or coil inductance
Solution Approach 1:
The patent applies preliminary action by measuring the induced voltage amplitude before data detection and using this measurement to dynamically determine the threshold voltage. The control circuit measures the amplitude of the induced voltage signal in the primary coil, performs A/D conversion, and sets the threshold voltage based on this preliminary measurement. This ensures that the threshold voltage automatically adapts to variations in power supply voltage or coil inductance before actual data detection occurs, resolving the contradiction between simple detection process and high detection accuracy.
2Measurement precision
If the threshold voltage is adjusted dynamically based on element variations, then the detection accuracy improves, but the device complexity increases due to additional control circuits
Solution Approach 1:
The control circuit performs multiple functions: it measures the induced voltage amplitude, performs A/D conversion, determines the threshold voltage dynamically, and detects data transmitted by load modulation. By integrating these functions into a single control circuit, the patent achieves high detection accuracy through dynamic threshold adjustment while minimizing the increase in device complexity. The same control circuit that manages power transmission also handles detection functions, making the system multi-functional without requiring separate dedicated detection hardware.
3Device complexity
If a simple comparator is used to detect induced voltage, then the device structure is simple, but the detection reliability deteriorates due to element constant variations
Solution Approach 1:
Before using the comparator to detect data, the system performs preliminary measurement of the induced voltage amplitude and dynamically sets the threshold voltage based on this measurement. This preliminary action ensures that the comparator operates with an accurate, adaptive threshold that compensates for element constant variations, thereby maintaining high detection reliability while keeping the overall structure relatively simple.
Solution Approach 2:
The system implements feedback by measuring the actual induced voltage amplitude and using this measurement to adjust the threshold voltage for subsequent data detection. The control circuit continuously monitors the amplitude and adapts the threshold accordingly, creating a closed-loop feedback mechanism that enhances detection reliability without requiring a completely complex detection circuit structure.
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 solution enables accurate and stable detection of data transmission and foreign object or detachment events even with variations in element constants, preventing incorrect reference threshold voltage detection and ensuring reliable operation.
Implementation Method 1
non-contact power transmission system transmitting power from the power transmission device to a power reception device by electromagnetically coupling a primary coil and a secondary coil
Implementation Method 2
an amplitude detection circuit that detects amplitude information relating to an induced voltage signal of the primary coil
Data Source
AI summary
A power transmission control device provided in a power transmission device of a non-contact power transmission system includes an amplitude detection circuit that detects amplitude information that relates to an induced voltage signal of a primary coil, an A/D conversion circuit that performs A/D conversion of the amplitude information, and a control circuit. The A/D conversion circuit performs A/D conversion of a detected voltage detected by the amplitude detection circuit at a conversion timing and determines digital data relating to a reference threshold voltage, the conversion timing being a timing after a given period has expired from a timing when the detected voltage has exceeded a provisional voltage. The control circuit performs at least one of data detection that detects data that has been transmitted from a power reception device by means of load modulation, foreign object detection, and detachment detection using the digital data relating to the reference threshold voltage.