Load-Independent ZVS Inverter for Wide-Range Wireless Power Transfer
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Solution Overview
Problem
Existing wireless power transfer systems, particularly those using Class E or Class EF2 inverters, are limited by their dependence on fixed load conditions and narrow operational ranges, making them inefficient at varying coil separation distances and load resistances, which restricts their application in high-frequency wireless power transfer.
Innovation Solution
A load-independent DC/AC inverter with a switched mode zero-voltage switching (ZVS) amplifier is developed, featuring a pair of circuits with transistors, capacitors, and inductors configured to maintain efficient operation across a wide range of load resistances, from open circuit to short circuit, and capable of converting between constant voltage and constant current outputs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If Class E or Class EF2 inverter configurations are used for high-frequency wireless power transfer, then power efficiency and simplicity are improved, but the system becomes highly dependent on fixed load conditions and operates efficiently only at a fixed coil separation distance
Solution Approach 1:
The patent implements a dynamic load adaptation mechanism that allows the inverter to adjust its operating parameters in real-time based on load conditions. The system transitions from fixed load dependence to dynamic load tracking by continuously monitoring output conditions and adjusting switching timing and duty cycles, enabling efficient operation across variable load ranges while maintaining power efficiency.
Solution Approach 2:
The patent changes key operating parameters including switching frequency, duty cycle, and timing characteristics based on detected load conditions. By dynamically adjusting these parameters, the system maintains optimal power efficiency across a wide range of load resistances and coil separation distances, resolving the contradiction between efficiency and adaptability.
2Device complexity
If Class E or Class EF2 inverter configurations are used, then device complexity is reduced, but the operational range is limited to a narrow load range and fixed coil separation distance
Solution Approach 1:
The patent introduces dynamic control mechanisms that enable the simple Class E or EF2 inverter architecture to adapt to varying operational conditions. By implementing real-time parameter adjustment of switching timing and duty cycles based on load detection, the system expands its operational range without adding significant structural complexity.
3Adaptability or versatility
If resonant magnetic systems are used to increase power transfer range, then alignment issues are rectified, but the system requires self-resonant inductors with capacitors which increases device complexity
Solution Approach 1:
The patent extracts and eliminates the requirement for self-resonant inductors with integrated capacitors from the system architecture. By using standard non-resonant inductors with externally controlled switching, the system achieves comparable or superior power transfer range without the complexity of resonant component design and tuning.
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 load-independent inverter ensures efficient power transfer over a broad load range and variable distances, maintaining zero-voltage switching and constant output voltage or current, enhancing the robustness and flexibility of high-frequency wireless power transfer systems.
Implementation Method 1
a transmitter coil configured to transfer power to a receiver coil via high frequency magnetic inductive coupling
Implementation Method 2
a receiver coil configured to extract power from the transmitter via magnetic field coupling
Data Source
AI summary
A load independent inverter comprises a switched mode zero-voltage switching (ZVS) amplifier. The switched mode ZVS amplifier comprising: a pair of circuits comprises: at least a transistor and at least a capacitor arranged in parallel; and at least an inductor arranged in series with the transistor and capacitor. The amplifier further comprises only one ZVS inductor connected to the pair of circuits; and at least a pair of capacitors connected to the ZVS inductor and arranged in series with at least an inductor and at least a resistor.