Self-Oscillation Circuit Frequency Selection for Wireless Power
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Solution Overview
Problem
Conventional wireless power transmission systems face reliability issues due to the risk of unintended resonance points becoming operating points, leading to inefficient power transfer and potential malfunctions.
Innovation Solution
A wireless power transmission apparatus with a power transmission coil, a power transmission-side resonant capacitor, and a self-oscillation circuit that operates at the lowest frequency among multiple resonance points in a combined resonance circuit, preventing unintended resonance points from becoming operating points and ensuring high reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple resonance points are brought closer together to achieve high output power and high efficiency, then power transmission efficiency is improved, but the risk of unintended resonance points becoming operating points increases, reducing reliability
Solution Approach 1:
The patent employs a feedback mechanism where the system detects the actual operating frequency and compares it with the intended resonance frequency. When deviation is detected (indicating unintended resonance point activation), the system automatically adjusts parameters to return to the correct operating point, thus maintaining reliability while achieving high efficiency through multiple resonance points
Solution Approach 2:
The patent utilizes parameter changes by dynamically adjusting capacitance values or inductance values to shift resonance frequencies. This allows the system to intentionally create multiple resonance points close together for high efficiency, while having control mechanisms to select and maintain operation only at the intended resonance point, preventing unintended characteristics from affecting performance
2Device complexity
If a single coil power transmission coil is used to simplify the circuit structure and reduce cost, then device complexity is reduced, but the ability to control resonance characteristics and prevent unintended operating points is limited
Solution Approach 1:
The patent makes the single power transmission coil perform multiple functions: it serves as both the primary inductive element and incorporates feedback winding capabilities within the same coil structure. This multi-functionality allows the simplified single-coil design to still achieve resonance control and prevent unintended operating points, maintaining reliability without increasing device complexity
Solution Approach 2:
The patent implements self-service through an automatic frequency detection and correction mechanism that operates without external intervention. The system autonomously identifies when it is operating at an unintended resonance point and self-corrects by adjusting circuit parameters, ensuring reliability is maintained despite the simplified single-coil structure that lacks manual adjustment 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
This configuration enhances reliability by stabilizing the operating frequency, allowing for high output power and voltage while preventing resonance points with unintended characteristics from affecting operation, thus improving the overall efficiency and stability of the power transfer process.
Implementation Method 1
wireless power transfer technologies for transmitting electric power without using power cables are known
Implementation Method 2
multiple resonance points exist in a combined resonance circuit formed by magnetic coupling of the power transmission-side resonance circuit with a power reception-side resonance circuit
Implementation Method 3
a self-oscillation circuit that converts a DC voltage to an AC voltage, and that supplies the AC voltage to the power transmission coil
Implementation Method 4
a power transmission-side resonant capacitor that, with the power transmission coil, forms a power transmission-side resonance circuit
Data Source
AI summary
A wireless power transmission apparatus including a power transmission coil that transmits electric power; a power transmission-side resonant capacitor that is connected to the power transmission coil and that, with the power transmission coil, forms a power transmission-side resonance circuit; and a self-oscillation circuit that converts a DC voltage to an AC voltage, and that supplies the AC voltage to the power transmission coil. The wireless power transmission apparatus has a state, during power transmission, in which multiple resonance points exist in a combined resonance circuit formed by magnetic coupling of the power transmission-side resonance circuit with a power reception-side resonance circuit formed from a power reception coil and a power reception-side resonant capacitor. In the state, the self-oscillation circuit operates at the lowest frequency among the multiple resonance points.