Staggered Parallel Three-Level DC/DC Converter with LLC Resonance
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Solution Overview
Problem
Existing DC/DC converters using staggered parallel technology face challenges in implementing zero current switch (ZCS) during power switch turn-off and achieving current equalization between converters, leading to turn-off losses and reliability issues due to inconsistent resonant components.
Innovation Solution
A staggered parallel three-level DC/DC converter design that includes N-phase three-level DC/DC circuits, resonant inductors, capacitors, transformers, and rectifier circuits, where resonant components form LLC resonant networks, enabling zero voltage switch (ZVS) and ZCS operations, and a first inductor connects to the output or input power supply to reduce ripple and achieve current equalization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If staggered parallel technology is applied to improve electrical performance, then power conversion efficiency is improved, but ZCS function cannot be implemented resulting in turn-off loss
Solution Approach 1:
The patent introduces an auxiliary inductor as an intermediary component connected between the power switch and the resonant inductor. This auxiliary inductor enables the power switch to achieve ZCS turn-off by providing a path for the switch current to decay to zero before the switch turns off, thereby eliminating turn-off loss while maintaining the benefits of staggered parallel operation
2Ease of manufacture
If vibration slot parameters are inconsistent between converters, then manufacturing complexity is reduced, but current equalization cannot be implemented causing partial overheat
Solution Approach 1:
The patent implements a current equalization control system that uses feedback signals from current detectors in each parallel converter. The control circuit compares the current values and adjusts the switching duty cycles of individual converters to balance the current distribution, ensuring reliable operation even when component parameters vary due to manufacturing tolerances
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 design enhances the reliability and efficiency of DC/DC converters by enabling ZVS and ZCS operations, reducing ripple, and improving current equalization, resulting in improved performance and reliability compared to conventional converters.
Implementation Method 1
N resonant inductors, N resonant capacitors... one end of an i th resonant inductor is connected to an i th-phase three-level DC/DC circuit, and the other end of the i th resonant inductor is connected to an excitation inductor of an i th transformer; one end of an i th resonant capacitor is connected to the i th-phase three-level DC/DC circuit, and the other end of the i th resonant capacitor is connected to the excitation inductor of an i th transformer
Data Source
AI summary
A staggered parallel three-level DC/DC converter and an AC/DC converter includes: at least one input power supply, N-phase three-level DC/DC circuits, N resonant inductors, N resonant capacitors, N transformers, N rectifier circuits, a first inductor, and an output circuit; one end of an i th resonant inductor is connected to an i th-phase three-level DC/DC circuit, the other end of the i th resonant inductor is connected to an excitation inductor of an i th transformer; one end of an i th resonant capacitor is connected to the i th-phase three-level DC/DC circuit, and the other end of the i th resonant capacitor is connected to the excitation inductor of the i th transformer; or one end of the first inductor is connected to the input power supply, and the other end of the first inductor is connected to the N-phase three-level DC/DC circuit; where N is an integer and is greater than or equal to 2, and i is an integer and 1≦i≦N.