Wireless Power Transmission Frequency Control via Current Detection
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Solution Overview
Problem
Existing wireless power transmission systems face instability in rectifier output due to unmonitored load states and are hindered by limitations in wireless communication, leading to potential disruptions and slow response times in controlling output voltage.
Innovation Solution
A wireless power transmission system that adjusts the driving frequency of the power feeding coil to match the resonance frequency of the power receiving side LC resonance circuit, establishing a proportional relationship between the alternating current in the power feeding coil and the rectifier output voltage, allowing for stable output voltage control without relying on wireless communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wireless communication is used to monitor the power receiving side state, then the control can be implemented, but the control speed is limited and disruptions may occur
Solution Approach 1:
The patent extracts the control function from the wireless communication-dependent system by using the current detection circuit to directly detect the alternating current in the power feeding coil. This extraction eliminates the need for wireless communication feedback, thereby resolving the contradiction between control reliability and control response speed.
Solution Approach 2:
The patent introduces a current detection circuit as an intermediary device that directly measures the alternating current in the power feeding coil. This intermediary provides immediate local feedback to the controller, enabling high-speed control without relying on wireless communication, thus resolving the contradiction between control stability and response speed.
2Ease of operation
If the driving frequency is adjusted to match resonance frequency, then the proportional relationship between current and output voltage is established, but the system complexity increases
Solution Approach 1:
The patent implements feedback by using the current detection circuit to detect the alternating current and the controller to adjust the driving frequency based on the detected current and the proportional relationship with output voltage. This feedback mechanism enables automatic output voltage control without manual intervention, resolving the contradiction between ease of operation and device complexity.
Solution Approach 2:
The patent changes the driving frequency parameter to match the resonance frequency of the power receiving side LC resonance circuit. This parameter change establishes a proportional relationship between the alternating current and rectifier output voltage, simplifying control operations despite the added frequency adjustment capability.
3Stability of the object's composition
If constant alternating current control is implemented, then stable rectifier output voltage is achieved, but the measurement and control complexity increases
Solution Approach 1:
The patent implements self-service by using the current detection circuit to automatically detect the alternating current and the controller to automatically adjust the driving frequency and maintain constant current. This self-service mechanism achieves stable output voltage without external intervention, resolving the contradiction between stability and measurement control difficulty.
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 approach maintains stable output voltage and enables high-speed response to load state changes without using wireless communication, ensuring consistent power delivery and efficient control of the rectifier output.
Implementation Method 1
a power feeding coil which receives an electric power to generate an AC magnetic field
Implementation Method 2
a power receiving side resonance capacitor which constitutes a power receiving side LC resonance circuit together with the power receiving coil
Data Source
AI summary
A wireless power transmission system includes a power feeding device and a power receiving device, wherein the power feeding device includes: a power feeding coil which receives an electric power to generate an AC magnetic field; an inverter for supplying an alternating-current power under a predetermined driving frequency to the power feeding coil; a current detection circuit for detecting a peak value of an alternating current flowing in the power feeding coil; and a controller for controlling the alternating current flowing in the power feeding coil. The power receiving device includes: a power receiving coil for receiving electric power wirelessly via the AC magnetic field; a power receiving side resonance capacitor which configures a power receiving side LC resonance circuit together with the power receiving coil; and a rectifier for rectifying the electric power received by the power receiving coil.