Noncontact Power Supply Frequency Control for Efficiency
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Solution Overview
Problem
Noncontact power supply systems face efficiency declines when the coupling coefficient between transmission and reception coils dynamically changes, making it difficult to maintain energy transmission efficiency.
Innovation Solution
A noncontact power supply apparatus with a power reception device featuring a resonance circuit, voltage detection circuit, and transmitter, and a power transmission device with a control circuit that adjusts the switching frequency of AC power supplied to the transmission coil based on measured output voltage, ensuring soft switching operation and optimal energy transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the coupling coefficient between transmission coil and reception coil is very low, then power transmission distance or flexibility is improved, but energy transmission efficiency deteriorates due to increased resonance current
Solution Approach 1:
The patent applies dynamics by making the resonance frequency of the reception side adjustable rather than fixed. The control circuit dynamically changes the resonance frequency based on the detected coupling coefficient, allowing the system to adapt to varying transmission distances and conditions while maintaining efficient power transfer and preventing excessive resonance current.
Solution Approach 2:
The patent implements feedback by having the control circuit continuously detect the coupling coefficient between transmission and reception coils, then use this information to adjust the resonance frequency of the reception side capacitor. This closed-loop control ensures the system operates at optimal efficiency across different coupling conditions.
2Ease of operation
If constant voltage output is achieved in SP method by selecting appropriate capacitance values, then compatibility with electric appliances is improved, but applicability in dynamic coupling environments deteriorates
Solution Approach 1:
The patent resolves this contradiction by making the resonance frequency dynamic rather than fixed. The control circuit adjusts the resonance frequency of the reception side based on real-time coupling coefficient detection, enabling the system to maintain constant voltage output for appliance compatibility while adapting to dynamic coupling conditions that would otherwise render fixed capacitance selections ineffective.
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 solution effectively suppresses energy transmission efficiency declines even with dynamic changes in the coupling coefficient, maintaining efficient power transfer by controlling the switching frequency to match the resonance frequency of the reception coil.
Implementation Method 1
a method of supplying power by electromagnetic induction is known
Implementation Method 2
a resonance circuit that includes a reception coil that receives electric power from the power transmission device and a resonance capacitor connected in parallel with the reception coil, the resonance circuit resonating at a first frequency
Data Source
AI summary
A power reception device 3 of a noncontact power supply apparatus 1 has a resonance circuit 20 that resonates at a first frequency, a voltage detection circuit 27 that measures an output voltage from the resonance circuit 20 and calculates a measured value of the output voltage, and a transmitter 28 that transmits a signal including information about the measured value of the output voltage to a power transmission device 2. The power transmission device 2 of the noncontact power supply apparatus 1 has a transmission coil 13 for supplying power to the power reception device, a power supply circuit 10 that supplies AC power having an adjustable switching frequency to the transmission coil 13, a receiver 14 that receives the signal including the information about the measured value of the output voltage, and a control circuit 16 that controls, in accordance with the measured value of the output voltage, the switching frequency so that the transmission coil 13 and the power supply circuit 10 can continue a soft switching operation.