Resonant Flyback Converter Control Across a Wide Output Voltage Range
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Solution Overview
Problem
Existing power converters using asymmetric half-bridge flyback converters face challenges in achieving high-efficiency operation across the entire output voltage range, particularly due to the inability to effectively adjust resonance characteristics.
Innovation Solution
The power converter incorporates a transformer, a resonant circuit, and a resonant adjustment circuit, along with a controller that dynamically adjusts the resonance operation and the activation timing of the resonance compensation based on the output voltage, ensuring efficient energy transmission across the full output voltage range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a parallel capacitor mechanism is added to improve efficiency at a single output voltage, then efficiency at that specific voltage is improved, but the converter still cannot achieve high efficiency across the full output voltage range
Solution Approach 1:
The patent applies dynamics by making the resonant circuit parameters adjustable rather than fixed. The controller dynamically changes the resonant capacitance value based on the output voltage level, transitioning from a static parallel capacitor approach to a dynamic adaptation mechanism that maintains optimal resonance across the full voltage range (5V to 48V).
Solution Approach 2:
The patent implements parameter changes by varying the resonant capacitance value according to the output voltage. Different capacitance values are selected for different voltage ranges, allowing the resonant frequency to be optimized at each operating point. This resolves the contradiction by enabling both high efficiency and wide voltage range adaptability through parameter adjustment.
2Ease of manufacture
If the resonant circuit uses a fixed capacitance value, then the circuit structure is simple, but high-efficiency operation cannot be achieved across the entire output voltage range
Solution Approach 1:
The patent applies segmentation by dividing the voltage range into multiple segments, each with its own optimized capacitance value. The resonant capacitor is divided into multiple sub-capacitors that can be independently switched, creating discrete capacitance steps. This maintains relative structural simplicity while enabling efficiency optimization across different voltage segments.
Solution Approach 2:
The patent transforms the fixed capacitance structure into a dynamic one by introducing switching elements that can reconfigure the resonant capacitance based on operating conditions. This dynamic adjustment capability allows the system to maintain high efficiency across the full voltage range without significantly complicating the overall circuit architecture.
3Adaptability or versatility
If the power converter uses asymmetric half-bridge flyback structure for wide voltage output, then voltage range is expanded, but the inability to achieve high-efficiency operation across the entire range becomes a technical bottleneck
Solution Approach 1:
The patent resolves this contradiction by introducing parameter changes to the resonant circuit, specifically adjusting the resonant capacitance value according to the output voltage level. This allows the asymmetric half-bridge flyback converter to maintain optimal resonance conditions across its wide voltage range, transforming it from a structure with inherent efficiency limitations to one that can achieve high efficiency throughout the full operating range.
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 enables dynamic adjustment of resonance operations, achieving immediate and complete resonance compensation, which enhances efficiency by reducing component losses and allowing the use of components with smaller current-withstanding capabilities, thereby reducing circuit costs.
Implementation Method 1
the resonant circuit includes a resonant capacitor and a resonant inductor provided by at least the primary-side winding
Implementation Method 2
The transformer includes a primary-side winding and a secondary-side winding coupled to the primary-side winding
Data Source
AI summary
A power converter includes a transformer, a resonant circuit, a first switch and a second switch, a resonant adjustment circuit, and a controller. The transformer includes a primary-side winding and a secondary-side winding coupled to the primary-side winding. The resonant circuit is coupled to the primary-side winding, and the resonant circuit includes a resonant capacitor and a resonant inductor provided by at least the primary-side winding. The first switch and the second switch are commonly connected to a node, and the node is coupled to the resonant circuit. The resonant adjustment circuit is coupled to the resonant circuit. The controller is used to control an enabled time of the resonant adjustment circuit according to an output voltage of the power converter so as to maintain the efficiency of transmitting the energy from the primary-side winding to the secondary-side winding under a full output voltage range.