Multi-Module Capacitive Wireless Power Transfer System
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Solution Overview
Problem
Capacitive wireless power transfer systems face challenges in achieving high power transfer levels at high efficiencies while maintaining fringing electric field strengths within safe limits, due to low coupling capacitance and high electric field strengths, which poses safety hazards and design complexities.
Innovation Solution
A multi-module capacitive wireless power transfer system employing phase-shifted capacitive modules with matching networks, inverters, and rectifiers to achieve high power transfer densities while reducing fringe electric field strengths through field cancellation and reactive compensation, using distributed plates and shunt reactive networks to mitigate parasitic capacitances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If capacitive WPT systems use high electric field strengths to achieve high power transfer levels, then power transfer density is improved, but safety hazards increase due to fringing field exposure
Solution Approach 1:
The system divides the capacitive power transfer into multiple independent modules, each operating at lower individual field strengths. The modules are arranged in an array where their combined effect achieves the required total power transfer density while each module's fringing fields remain below safety thresholds.
Solution Approach 2:
Multiple capacitive modules are combined in a phased array configuration where their electric fields are superimposed constructively in the coupling region to achieve high power transfer, while their fringing fields cancel or remain low in surrounding areas, maintaining safety compliance.
2Productivity
If capacitive WPT systems operate at high frequencies to increase power transfer density, then efficiency is improved, but parasitic capacitances and losses increase
Solution Approach 1:
The system segments the high-frequency power transfer into multiple lower-power modules operating in parallel. This segmentation reduces the parasitic capacitance effects in each individual module while maintaining the aggregate power transfer density through coordinated operation of all modules.
Solution Approach 2:
The system optimizes operating parameters including frequency selection within ISM bands, plate geometry, spacing, and material properties to maximize power transfer density while minimizing parasitic losses. Matching networks are designed to compensate for residual reactance and optimize the operating point.
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 greater than 90% efficiency and 50 kW/m² power transfer density with significantly reduced electric field strengths, ensuring safety and high power transfer capabilities across various applications, including electric vehicle charging.
Implementation Method 1
capacitive WPT systems, which utilize electrically coupled pairs of metal plates for power transfer. Each contactless plate-pair forms a capacitor, which when excited by an ac source and suitably compensated, can transfer power wirelessly.
Implementation Method 2
A multi-module capacitive wireless power transfer system employing phase-shifted capacitive modules with matching networks, inverters, and rectifiers to achieve high power transfer densities while reducing fringe electric field strengths through field cancellation
Data Source
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AI summary
A capacitive wireless power transfer (WPT) architecture that provides for dynamic (i.e., in motion) and/or stationary power transfer is provided. In various implementations, for example, the capacitive WPT architecture can achieve high power transfer levels at high efficiencies while maintaining fringing field strengths within acceptable safety limits. In one implementation, for example, a multi-module capacitive wireless power transfer system provides a capacitive charging system, such as for, but not limited to, charging electric vehicles (EV). In another implementation, a capacitive wireless power transfer module is provided. The module, for example, comprises a plurality of first coupling plates adapted to be coupled to a power source via an inverter; a plurality of second coupling plates adapted to be coupled to a load and to the plurality of first coupling plates for receiving wireless power and a matching network adapted to provide reactive compensation and gain.