A High-Gain Full-Bridge Isolated DC Converter with Multi-unit Diode Capacitor Network

Abstract

The present invention discloses a multi-unit diode capacitor network high-gain full-bridge isolated direct current converter. A transformer T is connected with an excitation inductor Lm in parallel and is connected with the leakage inductor Lk equivalent to the edge in series; an LC filtering circuit is composed of a filtering circuit Lf and a filtering capacitor Cf; and the anode of an input power supply Vdc is connected with the direct current side anode of a full-bridge inversion circuit, the cathode of the input power supply Vdc is connected with the cathode of the full-bridge inversion circuit direct current side, and a boost full-bridge inversion circuit is formed. The multi-unit diode capacitor network high-gain full-bridge isolated direct current converter can improve the voltage gain, obtain high voltage gain, reduce the voltage stress of a power device, reduce the turn ratio of a transformer, reduce the size of a magnetic element and improve the power density. The multi-unit diode capacitor network high-gain full-bridge isolated direct current converter employs the transformer leakage inductor and the circuit resonance to realize the zero current switching (ZCS) of a main power device to reduce the switch loss and improve the electric energy transition efficiency. The multi-unit diode capacitor network high-gain full-bridge isolated direct current converter has a wide application prospect in a new energy distributed power generation system.

Description

【Technical field】 [0001] The invention belongs to the field of distributed power generation such as new energy photovoltaics and fuel cells, and relates to a high-gain isolated DC conversion technology, in particular to a multi-unit diode capacitor network high-gain isolated full-bridge DC converter. 【Background technique】 [0002] The development and utilization of green energy such as solar energy and fuel cells has important strategic significance for optimizing my country's energy structure and achieving sustainable economic and environmental development. Different from traditional DC power sources, such as DC generators and storage batteries, photovoltaics and fuel cells have the characteristics of low output voltage and obvious voltage drop. One of the many technical bottlenecks in the system. [0003] Typical photovoltaic and fuel cell power generation systems are divided into two types: single-stage and two-stage. The single-stage structure inverter (DC-AC) only un...

AI Technical Summary

Problems solved by technology

However, due to the influence of parasitic parameters in the inductance loop of the main circuit and the performance of the controller, even if the duty cycle reaches the limit state close to 1, it is difficult to have a high voltage gain

The diode conducts in a very short time and bears relatively large voltage and current stress, which will inevitably lead to serious switching loss and EMI problems

Its existing technology is relatively mature and easy to implement

However, an excessively high turns ratio will affect the linearity of the transformer, cause serious magnetic flux leakage and bias problems, and increase the volume and leakage inductance, which will cause the turn-off voltage peak of the power semiconductor device, increase the voltage stress of the device, and reduce the conversion device efficiency

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