Switching Receiver Resonant Gate Drive Wireless Power
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Solution Overview
Problem
Conventional wireless power transfer systems suffer from power losses due to diode voltage drops and gate drive losses, especially at high switching frequencies, which reduce efficiency and are exacerbated by the use of miniaturized coils with high quality factors.
Innovation Solution
The implementation of a switching-type receiver using resonant gate drive and zero voltage switching in both the transmitter and receiver, which reduces power losses by recovering energy used for charging and discharging the gate capacitance of transistors through an LC oscillating circuit, allowing for higher switching frequencies and lower power losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional wireless power transfer systems use diodes for rectification, then power transfer can be achieved, but power losses occur due to diode voltage drops
Solution Approach 1:
The patent extracts and removes the diode rectification stage from the conventional wireless power transfer system. Instead of using diodes for rectification, the system employs synchronous rectification using active switches (MOSFETs or IGBTs) that are controlled to conduct during appropriate half-cycles, eliminating the voltage drop losses inherent in diode-based rectification.
Solution Approach 2:
The patent changes the operating parameters of the rectification process by transitioning from passive diode conduction to active switch-controlled conduction. The active switches are driven with gate signals that optimize the timing and duration of conduction, allowing for lower voltage drops and improved efficiency, especially at high switching frequencies.
2Productivity
If conventional systems operate at high switching frequencies, then power transfer speed increases, but gate drive losses increase
Solution Approach 1:
The patent implements feedback control mechanisms where the state of the active switches and the resonant tank circuit is continuously monitored. This feedback allows for optimization of the gate drive signals, adjusting timing and duration to minimize switching losses while maintaining high-frequency operation. The system adapts the gate drive parameters based on real-time circuit conditions.
Solution Approach 2:
The patent utilizes periodic switching action synchronized with the resonant frequency of the tank circuit. By timing the gate drive signals to coincide with the natural oscillations of the resonant circuit, the system achieves efficient power transfer at high frequencies while minimizing the energy required for gate driving, as switches are turned on and off at optimal moments in the oscillation cycle.
3Volume of moving object
If miniaturized coils with high quality factors are used, then system size decreases, but power losses are exacerbated
Solution Approach 1:
The patent replaces the conventional mechanical/diode-based rectification system with an electronic active switch-based system. This substitution allows for more precise control of the power transfer process, enabling the system to efficiently handle the high Q-factor characteristics of miniaturized coils without the parasitic losses that would otherwise be exacerbated by the coil's high quality factor.
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 approach enables wireless power transfer systems with reduced power losses, allowing for higher efficiency and the use of miniaturized coils with higher quality factors, leading to more effective power transfer while minimizing gate drive losses.
Implementation Method 1
The first coil adapted to be inductively coupled to a third coil in a power receiver, the second coil adapted to be inductively coupled to a fourth coil in the power receiver
Implementation Method 2
The implementation of a switching-type receiver using resonant gate drive and zero voltage switching in both the transmitter and receiver, which reduces power losses by recovering energy used for charging and discharging the gate capacitance of transistors through an LC oscillating circuit
Data Source
AI summary
A system includes a power receiver including an oscillator with a first coil and a second coil. The oscillator includes a first field effect transistor (FET) having first gate, first source, and first drain terminals, the first drain terminal coupled to the first coil, the first coil adapted to be inductively coupled to a third coil in a power transmitter. The oscillator also includes a first capacitor coupled to the first coil. The oscillator includes a second FET having second gate, second source, and second drain terminals, the second gate terminal coupled to the first capacitor, the second source terminal coupled to the first source terminal, and the second drain terminal coupled to the second coil, the second coil adapted to be inductively coupled to a fourth coil in the power transmitter. The oscillator includes a second capacitor coupled to the first gate terminal and coupled to the second coil.