Series Resonant Converter Dynamic Capacitance Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Series resonant converter circuits face challenges in maintaining a sinusoidal resonant current waveform and efficiency when load voltage and current fluctuate, leading to increased power loss and noise, especially in discharge loads like plasma devices where load impedance changes significantly.
Innovation Solution
A series resonant converter circuit that automatically adjusts resonant capacitance in response to changing load conditions, using a half-bridge configuration with primary and secondary resonant capacitors and diodes to maintain sinusoidal waveforms and reduce power loss without the need for additional switching mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the resonant converter operates with fixed resonant capacitance, then the circuit structure is simple, but the resonant current waveform deviates from sinusoidal when load voltage and current change, causing increased power loss and noise
Solution Approach 1:
The patent applies dynamics by making the resonant capacitance adjustable rather than fixed. The resonant capacitance is dynamically changed according to load conditions (output voltage and current) to maintain optimal resonant operation. This allows the converter to adapt to varying load impedance while keeping the resonant current waveform sinusoidal, thereby reducing power loss without significantly increasing circuit complexity.
Solution Approach 2:
The patent changes the parameter of resonant capacitance based on operating conditions. By detecting output voltage and current levels, the system selects appropriate resonant capacitance values to maintain resonance at the desired frequency. This parameter adjustment ensures sinusoidal current waveform and efficient power transfer across different load conditions, resolving the contradiction between simple structure and low power loss.
2Volume of moving object
If the resonant converter operates with fixed resonant capacitance, then the device is compact, but the resonant current waveform distorts under varying load conditions, increasing noise
Solution Approach 1:
The system dynamically adjusts resonant capacitance based on load conditions to maintain sinusoidal resonant current waveform. By keeping the waveform sinusoidal across varying loads, the system minimizes harmonic distortion and noise generation without requiring a larger device volume.
Solution Approach 2:
The resonant capacitance parameter is changed according to operating conditions to maintain optimal resonance. This ensures the resonant current remains sinusoidal under different load impedances, thereby reducing noise and electromagnetic interference while keeping the device compact.
3Ease of manufacture
If the resonant converter is designed for rated voltage operation, then the design is straightforward, but it cannot efficiently handle broad load ranges with drastically changing voltage and current
Solution Approach 1:
The patent implements dynamic adaptation by adjusting resonant capacitance based on detected output voltage and current levels. This allows the converter to efficiently operate across a broad load range, from rated voltage conditions to substantially lower voltages with higher currents, while maintaining sinusoidal resonant current waveform and good power transfer efficiency.
Solution Approach 2:
The resonant converter is designed with multi-functionality to handle various operating conditions. By incorporating adjustable resonant capacitance and control circuitry that detects load conditions, the single device can efficiently serve multiple functions across different voltage and current requirements, including discharge loads, capacitor loads, and charging applications.
4Adaptability or versatility
If a medium voltage tap is provided on transformer secondary winding to switch between high voltage/low current and low voltage/high current, then both output modes are achievable, but switching requires opening housing and discharging residual charge, reducing ease of operation
Solution Approach 1:
The patent replaces mechanical switching (opening housing, manual tap switching) with electronic control. The resonant capacitance is adjusted electronically based on detected load conditions, allowing automatic transition between high voltage/low current and low voltage/high current modes without mechanical intervention. This eliminates safety concerns and operational complexity while maintaining output flexibility.
Solution Approach 2:
The system performs self-adjustment by detecting its own output voltage and current levels and automatically selecting appropriate resonant capacitance values. This self-service mechanism enables automatic adaptation to different load conditions without requiring user intervention or manual switching, thereby improving ease of operation while maintaining 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
This solution ensures a sinusoidal resonant current waveform across a broad load range, reducing power loss and noise, and preventing feedback current to the DC power supply, thereby enhancing efficiency and reliability in power conversion.
Implementation Method 1
a series resonant converter circuit that utilizes a serial resonant effect of a resonant inductance means and a resonant capacitor
Data Source
AI summary
A series resonant converter circuit that reduces power loss is provided that includes an inverter circuit having at least a pair of first and second switching elements that is connected between DC input terminals, a transformer connected to this inverter circuit, a resonant inductance means that are connected in series to a primary winding wire or a secondary winding wire of the transformer, a primary-side resonant capacitor that is connected in series to the resonant inductance means through the first or second switching element, first and second secondary-side resonant capacitors that are connected to each other in series between the DC input terminals, first and second unidirectional elements that are connected to each other in series between the DC output terminals, and a resonant inductance means that cooperates with resonant capacitance from the primary-side resonant capacitor and the first and second secondary-side resonant capacitors to resonate in series.