AVR Rectifier Circuit for Fixed-Frequency WPT Coupling Compensation
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Solution Overview
Problem
Existing wireless power transfer (WPT) systems face challenges in maintaining high efficiency and power transfer capability across varying coupling conditions, especially at high frequencies, due to changes in coupling reactance.
Innovation Solution
The implementation of an active variable reactance (AVR) rectifier circuit, which comprises reactive components and appropriately controlled rectifiers, allows for continuous variation of compensating reactance while maintaining soft-switching, effectively addressing changes in coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the operating frequency is increased to decrease WPT system size, then system size is reduced, but maintaining soft-switching across wide operating conditions becomes difficult
Solution Approach 1:
The patent applies dynamics by making the compensating reactance adjustable and adaptive rather than fixed. The system dynamically adjusts the compensating reactance value based on operating conditions to maintain resonance and soft-switching at high frequencies, resolving the contradiction between size reduction and reliable operation.
Solution Approach 2:
The patent changes the parameter of compensating reactance to adapt to varying operating conditions. By adjusting this parameter, the system maintains resonance at high frequencies while preserving soft-switching characteristics, enabling both compact size and reliable operation.
2Adaptability or versatility
If traditional frequency tracking is used to compensate for coupling changes, then resonance frequency is maintained, but operating frequency must leave fixed ISM bands
Solution Approach 1:
The patent applies local quality by making only the compensating reactance adjustable while keeping the operating frequency fixed within ISM bands. This localized adjustment maintains resonance without requiring frequency drift, preserving both adaptability and frequency stability.
Solution Approach 2:
The system dynamically adjusts the compensating reactance value to track coupling changes while maintaining a fixed operating frequency. This dynamic compensation enables adaptability without compromising frequency stability or leaving designated ISM bands.
3Reliability
If a bank of capacitors is switched to maintain resonant frequency, then frequency stability is improved, but switch size and cost increase significantly for high power
Solution Approach 1:
The patent uses preliminary action by pre-calculating or pre-adjusting the compensating reactance value based on predicted or detected coupling conditions. This allows the system to maintain frequency stability without requiring large, complex switching networks, as adjustments are made proactively rather than reactively.
Solution Approach 2:
The system employs a dynamic compensating reactance that can be continuously or stepwise adjusted, replacing the need for large banks of capacitors and complex switching networks. This dynamic approach maintains frequency stability with simpler, more scalable components suitable for high power applications.
4Adaptability or versatility
If rectifier switch turn-on/off is phase shifted to provide compensating reactance, then continuously variable reactance is achieved, but additional losses and loss of zero-voltage switching occur
Solution Approach 1:
The patent segments the compensating reactance function from the power rectification function. By using a separate adjustable compensating reactance component, the rectifier switches can operate optimally for power conversion while the compensating reactance is independently adjusted, avoiding additional losses and preserving zero-voltage switching.
Solution Approach 2:
The patent extracts the compensating reactance function from the rectifier circuit itself and places it in a separate, dedicated component. This separation allows the rectifier to maintain optimal switching characteristics for minimal losses while the compensating reactance is independently controlled to provide the necessary adaptation.
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 AVR rectifier circuit enables high power transfer capability and efficiency in WPT systems by continuously compensating for changes in coupling reactance, even at fixed operating frequencies, thereby improving system performance across varying conditions.
Implementation Method 1
Wireless power transfer (WPT) provides convenience, enables new functionality and improves our quality of life by enabling autonomous charging in applications ranging from electric vehicles (EVs) and robotics to portable electronics and biomedical implants
Implementation Method 2
WPT systems need to operate at frequencies close to the resonance frequency of a resonant tank formed by the coupling capacitance or inductance of their coupler and the reactance of the compensation components
Implementation Method 3
the resonance frequency of a resonant tank formed by the coupling capacitance or inductance of their coupler and the reactance of the compensation components
Implementation Method 4
WPT systems need to operate at frequencies close to the resonance frequency of a resonant tank
Data Source
AI summary
In one example, an active variable reactance rectifier circuit includes an active variable reactance rectifier circuit input port and an output port. A power splitter circuit includes an input port coupled to the active variable reactance rectifier circuit input port and a pair of output ports. A first rectifier circuit includes an input port is coupled to the first power splitter circuit output port. A second rectifier circuit includes an input port coupled to the second power splitter circuit output port. A power combiner circuit includes a first input port, a second input port and an output port. The first power combiner circuit input port is coupled to the first rectifier circuit output port, the second power combiner circuit input port is coupled to the second rectifier circuit output port and the power combiner circuit output port is coupled to the active variable reactance rectifier circuit output port.