Power Transmission Control Device for Stable Load Detection
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Solution Overview
Problem
Existing non-contact power transmission systems face challenges in accurately detecting changes in secondary-side loads due to variations in element constants like power supply voltage or coil inductance, and environmental changes affect detection accuracy.
Innovation Solution
A power transmission control device that includes a drive clock signal generation circuit, a driver control circuit, a waveform adjusting circuit, and a pulse width detection circuit to detect changes in secondary-side loads by measuring pulse width information, allowing for stable and accurate load detection without individual voltage and current detection methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If threshold voltage comparison method is used to detect load changes, then detection simplicity is improved, but detection accuracy deteriorates due to variations in element constants
Solution Approach 1:
The patent changes the detection parameter from voltage amplitude to pulse width. By measuring the duration of the rectified voltage pulse rather than its amplitude, the system becomes insensitive to variations in element constants like coil inductance and power supply voltage, while maintaining simple detection circuitry.
2Measurement precision
If individual voltage and current detection methods are used, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent merges voltage and current detection into a single pulse width measurement. The rectified voltage signal's pulse width inherently reflects the load condition, eliminating the need for separate voltage and current sensing circuits while maintaining accurate load detection.
Solution Approach 2:
The rectified voltage signal serves as an intermediary that indirectly provides load information through its pulse width characteristic. This mediator approach simplifies the detection system by using a single signal that encodes load conditions in its temporal rather than amplitude characteristics.
3Adaptability or versatility
If monitoring means measures current pulse duration, then foreign object detection capability is improved, but detection accuracy deteriorates under environmental changes
Solution Approach 1:
The patent changes the measurement parameter from current amplitude to voltage pulse width. This parameter transformation makes the detection immune to environmental factors like temperature changes that affect current characteristics, while preserving the ability to detect foreign objects through load modulation.
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 stable and accurate detection of secondary-side load changes, ensuring reliable data transfer and improved detection accuracy by simplifying the configuration and combining with amplitude detection methods.
Implementation Method 1
non-contact power transmission system transmitting power from the power transmission device to the power reception device by electromagnetically coupling a primary coil and a secondary coil
Data Source
Figure 1A~1B
Figure 2
Figure 3A~3B
AI summary
A power transmission control device (20) provided in a power transmission device (10) of a non-contact power transmission system includes a drive clock signal generation circuit (25) that generates a drive clock signal that specifies a drive frequency of a primary coil (L1), a driver control circuit (26) that generates a driver control signal based on the drive clock signal and outputs the driver control signal to a transmission driver (12), a waveform adjusting circuit (32) that outputs a waveform adjusting signal of an induced voltage signal of the primary coil (L1), a pulse width detection circuit (33) that receives the waveform adjusting signal and the drive clock signal and detects pulse width information relating to the waveform adjusting signal, and a control circuit (22) that detects a change in secondary-side load (40) based on the detected pulse width information.