Variable Inductor Resonant Converter for Soft Switching
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Solution Overview
Problem
Existing resonant converters face challenges in increasing their resonance operation range, reducing switching losses, and decreasing stress on converter components, especially when operating outside their resonant range, leading to increased switching losses and component stress.
Innovation Solution
A zero-voltage transition zero-current transition resonant converter with a variable resonant tank is implemented, featuring a toroidal core with a winding and a DC biasing coil that allows for varying inductance by magnetic saturation, enabling expanded resonant operating ranges and reduced switching losses through controlled impedance adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If resonant converters operate outside their resonant operating range, then the converter can handle varying load conditions, but switching losses increase and stress on switches increase
Solution Approach 1:
The patent applies dynamics by making the inductance value variable rather than fixed. The resonant tank includes a variable inductor whose inductance can be adjusted dynamically to maintain resonant conditions across different operating ranges. This allows the converter to adapt to varying load conditions while staying in resonance, thereby preventing increased switching losses and component stress that would occur when operating outside the resonant range with fixed inductance.
Solution Approach 2:
The patent implements parameter changes by varying the inductance value of the resonant tank inductor. By changing the inductance parameter dynamically, the resonant frequency of the tank can be adjusted to match the switching frequency across different operating conditions. This ensures the converter operates within its resonant range regardless of load variations, eliminating the trade-off between adaptability and switching losses.
2Adaptability or versatility
If resonant converters operate outside their resonant operating range, then the converter can handle varying load conditions, but stress on converter components increase
Solution Approach 1:
The variable inductance mechanism enables the resonant tank to dynamically adjust its characteristics, allowing the converter to maintain resonant operation across a wider range of load conditions. This dynamic adjustment prevents the switches from experiencing excessive stress that would occur when operating outside the resonant range, as the converter can adapt its resonant frequency to match the switching frequency under varying loads.
Solution Approach 2:
By changing the inductance parameter of the resonant tank, the converter can maintain optimal operating conditions across different load levels. This parameter adjustment ensures that the resonant frequency aligns with the switching frequency, preventing excessive voltage and current stress on the switches that would otherwise occur when operating outside the resonant range.
3Device complexity
If fixed inductance is used in resonant tank, then the converter structure is simpler, but the resonant operating range is limited
Solution Approach 1:
The patent employs a variable inductor in the resonant tank that can dynamically adjust its inductance value. This dynamic capability expands the resonant operating range of the converter without requiring multiple fixed inductance values or complex switching mechanisms. The variable inductor provides a straightforward implementation that balances structural simplicity with enhanced adaptability.
Solution Approach 2:
The patent utilizes parameter changes by implementing a variable inductance value in the resonant tank. This allows the resonant frequency to be adjusted to match different switching frequencies and load conditions, significantly expanding the operational range. The implementation uses a practical variable inductor design that maintains reasonable structural complexity while achieving the desired versatility.
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 solution extends the resonant operating range, reduces switching losses, and decreases stress on converter components by allowing soft switching with reduced inductor size and energy storage, enhancing efficiency and performance.
Implementation Method 1
A zero-voltage transition zero-current transition resonant converter with a variable resonant tank is implemented, featuring a toroidal core with a winding and a DC biasing coil that allows for varying inductance by magnetic saturation
Data Source
AI summary
Unique systems, methods, techniques and apparatuses for a ZVT ZCT resonant converter with a variable resonant tank are disclosed. One exemplary embodiment is a system comprising a bidirectional resonant converter comprising an input/output terminal, a switching device coupled with the input/output terminal, a resonant circuit coupled with the switching device and including a variable inductor, an output/input terminal coupled with the resonant circuit, and a DC biasing circuit operatively coupled with the variable inductor. The variable inductor comprises a toroidal core, a first winding wound around the toroidal core and coupled with the switching device and the output/input terminal, a second core structured to overlap a portion of the toroidal core, and a second winding wound around the second core and coupled with the DC biasing circuit. The DC biasing circuit is controllable to vary the inductance of the variable inductor by saturating a portion of the toroidal core.