Phase-Shift Full-Bridge Converter Clamp for Lower Diode Loss
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Solution Overview
Problem
The existing phase shift full bridge (PSFB) converters suffer from increased power loss due to high peak voltages in diodes, which necessitate higher voltage specifications and reduce efficiency and economic feasibility.
Innovation Solution
Incorporating auxiliary capacitors in parallel with switches of the primary portion of the transformer, along with clamp diodes, to manage current flow and reduce voltage fluctuations, thereby minimizing power loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a traditional PSFB converter topology is used, then the converter structure is simple, but the clamp diode experiences high peak voltage leading to increased power loss and reduced efficiency
Solution Approach 1:
The patent introduces auxiliary capacitors as intermediary components connected in parallel with the clamp diodes. These capacitors serve as mediators that store and release energy, thereby reducing the peak voltage stress on the clamp diodes and lowering their power loss without fundamentally changing the PSFB converter topology
Solution Approach 2:
The auxiliary capacitors are pre-charged during specific switching intervals before the high-voltage stress periods occur. By preparing the capacitors in advance to hold charge, the system reduces the instantaneous voltage peaks that would otherwise appear across the clamp diodes, thereby reducing power loss before it occurs
2Reliability
If the voltage specifications of the diode are increased to handle higher peak voltages, then the diode can withstand the stress, but the economic feasibility and efficiency decrease
Solution Approach 1:
The auxiliary capacitors act as intermediary energy storage devices that share the voltage stress burden. By placing capacitors in parallel with the clamp diodes, the peak voltage across the diodes is reduced, allowing the use of diodes with lower (and thus more economical) voltage ratings while maintaining reliable operation
Solution Approach 2:
The patent changes the voltage parameter characteristics across the clamp diodes by introducing the auxiliary capacitors. This modifies the voltage waveform to have lower peak values, enabling the selection of diodes with optimized (lower) voltage specifications that are more cost-effective while still providing adequate reliability
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 proposed solution increases power efficiency by up to 1.15% compared to conventional PSFB converters, enhancing overall efficiency and reducing diode stress.
Implementation Method 1
an auxiliary capacitor having one end connected to a first node and the other end connected to a second node
Implementation Method 2
the diode has an increased peak voltage, due to a resonance between the resonance inductor Lr and a parasitic capacitor of the diode
Data Source
AI summary
A phase shift full bridge (PSFB) converter includes a switch portion including first to fourth switches connected in a form of a full bridge, a transformer configured to convert the output of the switch portion, a rectifying portion including at least one of a switch and a diode and configured to rectify the output of the transformer, a resonance inductor having an end connected to another end of a primary portion of the transformer and another end connected to a node between the third switch and the fourth switch, a first clamp diode having an end connected to an end of the first switch and another end connected to the other end of the primary portion of the transformer, and a second clamp diode having an end connected to the other end of the primary portion of the transformer and another end connected to another end of the second switch.