Bidirectional cascade-input cascade-output DC-DC transformation topological structure

Abstract

The invention provides a bidirectional cascade-input cascade-output DC-DC transformation topological structure. A primary side circuit comprises a DC power supply, a capacitor and a primary-side single-phase full bridge. The primary-side single-phase full bridge comprises at least one single-phase full-bridge module. Each single-phase full-bridge module comprises a first bridge arm and a second bridge arm, which are connected in parallel. The capacitor and the primary-side single-phase full bridge are connected in parallel at the two sides of the DC power supply; and bridge arm midpoints of the primary-side single-phase full bridge are connected to the input end of a high-frequency transformer. A secondary side circuit comprises a DC power supply, a capacitor and a secondary-side single-phase full bridge. The secondary-side single-phase full bridge comprises a plurality of single-phase full bridge modules; the capacitor and the secondary-side single-phase full bridge are connected in parallel at the two sides of the DC power supply; and bridge arm midpoints of the secondary-side single-phase full bridge are connected to the output end of the high-frequency transformer. In case of large current at the primary side and high voltage at the secondary side, each switch tube bears low voltage stress, charge and discharge efficiency is high, voltage rise speed is fast and the structure is simple; and in case of high voltage at the primary side and high current at the secondary side, the current stress of each switch tube is small and the output current is stable.

Description

technical field [0001] The invention relates to the technical field of voltage converters, in particular to a bidirectional cascaded input cascaded output DC-DC conversion topology. Background technique [0002] In recent years, electric vehicles have been strongly supported by national policies due to their significant advantages such as energy saving and environmental protection, and have developed well. More and more universities, design institutes and automobile companies have begun to conduct in-depth research. On-board power supply is one of the cores of new energy vehicles, and more and more micro-grids have become the power supply system for electric vehicle charging and swapping stations. Therefore, there is a need for a power converter capable of effectively utilizing new energy to generate electricity and effectively improving the quality of power supply to control charging and discharging of an energy storage system. And with the rapid development of my country'...

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Problems solved by technology

The traditional DC-DC converter adopts the working mode of hard switching, and the loss of the switching tube is the main factor affecting its working efficiency; the loss of the switching tube mainly comes from two aspects, one is that the switching tube is turned on and off due to The opening loss caused by the simultaneous existence of voltage and current; the second is the conduction loss caused by the existence of its own on-resistance when the switch tube is turned on

[0004] The current DC-DC converters mainly exist in the form of single-phase full-bridge topology. The topology current rises slowly and the charging efficiency is low. When the secondary side needs to output a large current, the current stress on the switch tube is relatively large. Big

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