Contactless Power Converter Control at Fixed Resonant Frequency
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Solution Overview
Problem
Resonance-based contactless power transfer systems face inefficiencies due to variations in system frequency caused by changes in load power during charging cycles, affecting power transmission efficiency.
Innovation Solution
A contactless power transfer system that includes a first power converter to convert direct current power to alternating current power at a system frequency, a first power exchanger coil to transmit this power via a magnetic field, and a controller to adjust the operating state of the power converter based on sensed voltage or current, thereby varying the alternating current power to match changing load requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the system frequency is varied to match changing load power requirements during charging cycles, then the load power requirements are met, but the power transmission efficiency deteriorates
Solution Approach 1:
The patent applies parameter changes by varying the duty cycle of the power converter instead of changing the system frequency. The duty cycle modulation allows the system to adapt to different load power requirements while maintaining a fixed resonant frequency, thus preserving power transmission efficiency while meeting varying load demands
Solution Approach 2:
The system dynamically adjusts the power converter's operating parameters (duty cycle) in response to changing load conditions. This dynamic control enables the system to maintain optimal efficiency by keeping the resonant frequency constant while adapting the power delivery through duty cycle variations
2Loss of energy
If the system operates at a fixed frequency to maintain power transmission efficiency, then the efficiency is preserved, but the ability to adapt to varying load power requirements is limited
Solution Approach 1:
The patent changes the controlled parameter from frequency to duty cycle. By modulating the duty cycle of the power converter while maintaining fixed frequency operation, the system achieves both high efficiency (through frequency stability) and adaptability (through duty cycle adjustment to match varying load power requirements)
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 maintains power transfer efficiency by operating at a fixed system frequency despite varying load power, improving overall contactless power transfer efficiency.
Implementation Method 1
transferring the alternating current power from the first power exchanger coil to the second power exchanger coil at the system frequency via a magnetic field
Implementation Method 2
The resonance based coupling systems employ resonant coils, which are operated at a system frequency to transmit power between the two locations via a magnetic field
Data Source
AI summary
A contactless power transfer system is provided. The contactless power transfer system includes a first power exchanger coil configured to exchange power. The contactless power transfer system also includes a first power converter operatively coupled to the first power exchanger coil and configured to convert a direct current power to an alternating current power at a system frequency. The contactless power transfer system further includes a controller configured to control an operating state of the first power converter to vary an alternating current power provided to the first power exchanger coil at the system frequency.