Hybrid DC converter

Abstract

The present invention discloses a hybrid DC converter. The hybrid DC converter is formed by connecting a high frequency resonant converter and a dual active bridge converter in parallel, the high frequency resonant converter and the dual active bridge converter are connected end to end orderly, and the high frequency resonant converter comprises a full-bridge inverter A, a high-frequency transformer and an uncontrolled rectifier bridge. The full-bridge inverter A and the uncontrolled rectifier bridge are connected with the head end and the tail end of the high-frequency transformer respectively, the dual active bridge DC converter comprises a full-bridge inverter B, a medium frequency transformer and a fully-controlled rectifier bridge, and the full-bridge inverter B and the fully-controlled rectifier bridge are connected with the head end and the tail end of the medium frequency transformer respectively. The hybrid DC converter of the present invention combines the advantages of the high frequency resonant converter and the dual active bridge DC converter and considers the current capability of a high frequency resonant capacitor, the high frequency resonant converter only realizes the effect of clamping a terminal voltage, and the large-power electric energy transmission completely depends on the dual active bridge DC converter, thereby guaranteeing the stable terminal voltage and the power transmission capability. The converter overall adopts a closed loop PI control strategy.

Description

technical field [0001] The invention relates to a DC converter, in particular to a hybrid DC converter. Background technique [0002] With the increasing speed of social development, human demand for energy continues to increase, and the contradiction between the depletion of fossil energy and the high demand for energy in social development forces people to pay more and more attention to the development and utilization of renewable energy. Utilizing renewable energy such as scattered wind energy, solar energy, and ocean energy, and developing Distributed Generation (DG) according to local conditions is an important way to achieve "clean replacement" and "electric energy replacement". At the same time, China's photovoltaic power generation capacity will reach 4GW. However, limited by the capacity of the power system, most renewable energy has not been effectively utilized, and even the phenomenon of "abandoning wind" and "abandoning light" has occurred; on the other hand, w...

AI Technical Summary

Problems solved by technology

The soft-switching characteristics of the phase-shifted full-bridge converter are poor, and it is difficult to ensure the overall efficiency of the converter

The LLC type resonant converter can guarantee soft switching characteristics in the full load range and has constant voltage regulation capability, but in the case of high frequency, the power transmission is limited by the current capacity of the resonant capacitor

The power transmission of the DAB converter depends on the stable terminal voltage, so the control link of this type of converter is often very complicated

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