Wireless Power Tuning Circuit for Stable Parallel Resonance
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Solution Overview
Problem
Conventional wireless power feeding systems using series resonant circuits face efficiency losses due to resonance frequency fluctuations caused by the position and posture of the power reception device, leading to increased costs and complexity, while parallel resonant circuits are deemed unsuitable for wireless power feeding due to voltage spikes and efficiency limitations.
Innovation Solution
A wireless power feeding system employing a parallel resonant circuit on the power feeding side with a driving method and resonance frequency adjustment technique, utilizing a switch circuit and control circuit to manage the power feeding coil's magnetic flux and resonance frequency, ensuring high efficiency and low heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a series resonant circuit is used for wireless power feeding, then power transmission capability is improved, but resonance frequency fluctuations occur due to position and posture changes of the power reception device, leading to efficiency losses
Solution Approach 1:
The patent changes the fundamental circuit configuration parameter from series resonant to parallel resonant circuit. This parameter change allows the system to maintain stable resonance frequency despite position and posture variations of the power reception device, thereby preventing efficiency losses while maintaining power transmission capability.
Solution Approach 2:
The patent inverts the conventional approach by using a parallel resonant circuit instead of a series resonant circuit on the power feeding side. This inversion of the circuit topology resolves the issue of resonance frequency fluctuations caused by coupling variations, achieving stable power transmission without efficiency penalties.
2Reliability
If a parallel resonant circuit is used for wireless power feeding, then voltage spikes occur leading to efficiency limitations and unsuitability for power transmission
Solution Approach 1:
The patent introduces dynamic control through a driving circuit that periodically switches the power feeding coil between connected and disconnected states. This dynamic operation prevents continuous voltage buildup in the parallel resonant circuit, eliminating voltage spikes while maintaining effective power transmission capability.
Solution Approach 2:
The patent implements periodic switching of the power feeding coil connection through a driving circuit. This periodic action creates controlled transient states that prevent sustained voltage spikes in the parallel resonant circuit, enabling reliable power transmission while maintaining voltage stability.
3Loss of energy
If resonance frequency adjustment is implemented to maintain efficiency, then device complexity and cost increase
Solution Approach 1:
The patent employs a parallel resonant circuit that inherently maintains stable resonance frequency without requiring external adjustment mechanisms. The circuit self-regulates its resonant characteristics despite variations in coupling conditions, eliminating the need for additional frequency adjustment devices and reducing system complexity.
4Length of stationary object
If series resonant circuit is used, then power transmission over distance is achieved, but heat generation increases due to efficiency losses
Solution Approach 1:
The patent changes the circuit configuration parameter from series to parallel resonant circuit, which inherently maintains stable resonance frequency over varying distances. This parameter change eliminates efficiency losses that would otherwise convert to heat, enabling long-distance power transmission without excessive heat generation.
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 system achieves high power feeding efficiency with reduced losses and heat generation, capable of transmitting energy over a wider range and distance with improved reliability, making it suitable for multiple power receivers.
Implementation Method 1
a power feeding coil for generating a magnetic flux... electrical energy is supplied from the power feeder to the power receiver by the electromagnetic induction
Implementation Method 2
a power feeding side resonant capacitor forming a parallel resonant circuit in combination with the power feeding coil... utilizing a resonance phenomenon
Data Source
AI summary
A system for performing wireless power feeding using an existing electronic device. In the present invention, a power feeder has a power feeding coil. A power receiver has a power receiving coil, a power receiving circuit unit, and a load. Electromagnetic induction using a resonance phenomenon causes the power feeder to supply an electric energy to the power receiver. A switching circuit enables the power feeding coil to periodically repeat turning on (driving state) and turning off (resonant state) of power supply. A resonant frequency of the power receiver is substantially a period combining a time of the driving state and a time of the resonant state. A resonant frequency of the power feeder is substantially a period of the time of the resonant state, and a tuning adjusting circuit performs adjustment of a resonant capacitor and a coil.