Hybrid direct current converter

Abstract

The present invention discloses a hybrid direct current converter. The converter is formed by connecting a high-frequency resonance converter and a dual-active bridge converter in parallel, the high-frequency resonance converter and the dual-active bridge converter are connected from the head to the tail, and the high-frequency resonance converter includes 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 respectively connected with the head and the tail ends of the high-frequency transformer; the dual-active bridge direct current converter includes a full-bridge inverter B, a medium frequency transformer and a fully-controlled thyristor rectifier; and the full-bridge inverter B and the fully-controlled thyristor rectifier are respectively connected with the head and the tail ends of the medium frequency transformer. The hybrid direct current converter combines the advantages of the high-frequency resonance converter and the dual-active direct current bridge converter, the current ability of the high-frequency resonant capacitor is considered, the high-frequency resonant capacitor can only bear the effect of the clamping terminal voltage, and the large-power electric power transmission completely depends on the dual-active bridge converter, and therefore, the stability and the power transmission power of the terminal voltage is ensured, and the integral closed loop PI control strategy is employed by the converter.

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. It is an important way to realize "clean replacement" and "electric energy replacement" by utilizing scattered renewable energy such as wind energy, solar energy, ocean energy, etc., and developing distributed generation (Distributed Generation, DG) according to local conditions. 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" ha...

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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