Multi-coil Wireless Power Transmission with Phase Cancellation
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Solution Overview
Problem
Contactless electric power transmission systems face challenges in reducing leakage magnetic fields, which interfere with external devices, especially when high-power transmission is required for charging high-capacity batteries, as the increased radio frequency current enhances leakage magnetic field intensity, necessitating a solution to minimize interference while maintaining efficient power transfer.
Innovation Solution
The implementation of a system with multiple power transmitters generating magnetic fields of opposite phases and frequency hopping, where the frequency shift is limited by an upper shift width to maintain the leakage magnetic field reduction effect, combining magnetic-magnetic field cancellation and spread spectrum processes to reduce leakage magnetic field intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-power contactless power transmission is performed to charge high-capacity batteries in short time, then power transmission speed is improved, but leakage magnetic field intensity increases causing interference with broadcasting and wireless communication
Solution Approach 1:
The patent divides the power transmission system into multiple independent power transmission circuits (at least two circuits). Each circuit transmits power through its own coil, allowing the total power to be distributed across multiple channels. This segmentation enables high-power transmission while reducing the magnetic field intensity per circuit, thereby minimizing leakage magnetic field interference with external devices.
Solution Approach 2:
The patent changes the operational parameters by using multiple power transmission circuits operating at the same or different frequencies. By distributing the power transmission across multiple circuits, the system achieves high-power transmission without proportionally increasing the leakage magnetic field intensity of any single circuit, thus resolving the contradiction between transmission speed and magnetic field interference.
2Object-generated harmful factors
If multiple power transmission circuits are used to reduce leakage magnetic field, then magnetic field interference is reduced, but system complexity increases
Solution Approach 1:
The patent combines multiple power transmission circuits into a unified control system managed by a single controller. The controller coordinates the operation of all circuits, managing power distribution and frequency allocation centrally. This merging approach reduces system complexity by providing centralized control rather than requiring independent management of each circuit.
Solution Approach 2:
The controller in the patent serves multiple functions: it controls power transmission across all circuits, manages frequency allocation, monitors power reception, and coordinates the operation of multiple coils. This multi-functionality reduces the need for separate control systems for each circuit, thereby reducing overall system complexity while maintaining the benefits of multiple transmission channels.
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 effectively reduces leakage magnetic field interference while ensuring stable and efficient power transmission by canceling magnetic fields and spreading the frequency spectrum, thereby preventing increased magnetic field intensity during frequency shifting.
Implementation Method 1
a power transmission circuit generates a radio frequency (high-frequency) current with a predetermined frequency. A power transmission coil is excited by the radio frequency current and power is transmitted through a magnetic field generated by the excitation
Implementation Method 2
The power transmitters sequentially shift frequencies of respective magnetic fields to the same value at the same timing. A shift width of each of the frequencies for one-time shifting is limited by an upper limit value
Data Source
AI summary
An electric power transmission device as an aspect of the present invention includes a plurality of power transmitters configured to respectively generate magnetic fields. Phases of the respective magnetic fields are set such that the respective magnetic fields cancel out each other. The power transmitters sequentially shift frequencies of the respective magnetic fields to the same value at the same timing. A shift width of each of the frequencies for one-time shifting is limited by an upper limit value.