Bidirectional DC/DC converter and control method thereof

Abstract

The invention discloses a bidirectional DC / DC converter and a control method thereof. The bidirectional DC / DC converter comprises a coupling inductor, six switching tubes, three capacitors and a resonant inductor, wherein the first end of the coupling inductor serves as a low-voltage side anode, the second end of the coupling inductor is connected with the first switching tube and the first capacitor, the third end of the coupling inductor is connected with the third switching tube, the fourth switching tube and the second capacitor, the first end of the first switching tube is connected withthe second switching tube and the third capacitor as a cathode, the second end of the first switching tube is connected with the first capacitor, the second end of the first capacitor is respectivelyconnected with the third switching tube and the second switching tube, the second end of the third switching tube is respectively connected with the fourth switching tube and the second capacitor, thesecond end of the second capacitor is respectively connected with the resonant inductor and the sixth switching tube, the second end of the fourth switching tube is respectively connected with the fifth switching tube and the third capacitor, the second end of the resonant inductor is connected with the fifth switching tube, and the second end of the sixth switching tube serves as a high-voltageside anode. The bidirectional DC / DC converter of the invention has the advantages of high voltage conversion ratio, small device voltage stress, small ripple current and the like.

Description

technical field [0001] The invention relates to the technical field of DC converters, in particular to a bidirectional DC / DC converter and a control method thereof. Background technique [0002] Bidirectional DC / DC converters have been widely used in new energy grid-connected systems and energy storage systems. In order to achieve a large voltage conversion ratio, the traditional bidirectional DC / DC converter often adopts the structure of a high-frequency isolation transformer, but the structure of the high-frequency isolation transformer is relatively complicated, and its volume and cost are relatively large. Although the traditional non-isolated bidirectional DC / DC converter has a simple structure, it also has disadvantages such as small voltage conversion ratio and large device voltage stress. The invention proposes a novel non-isolated bidirectional DC / DC converter topology, which has the characteristics of high voltage conversion ratio, less device voltage stress, and ...

AI Technical Summary

Problems solved by technology

In order to achieve a high boost ratio and reduce the voltage stress of switching devices, switched capacitors are gradually introduced into bidirectional DC / DC converters, but the introduction of switched capacitors will bring inrush current, which will affect the safe operation of the circuit

[0004] Literature H.Ardi, A.Ajami, F.Kardan and S.N.Avilagh, "Analysis and Implementation of a Nonisolated Bidirectional DC–DC Converter With HighVoltage Gain," in IEEE Transactions on Industrial Electronics, vol.63, no.8, pp.4878 -4888, Aug.2016, doi:10.1109 / TIE.2016.2552139. A non-isolated bidirectional DC / DC converter is proposed, which has the advantages of high voltage conversion ratio, high efficiency, and simple control. The voltage stress is very large, which is 1 to 2 times that of the high-voltage side voltage, and the boost ratio needs to be improved, and the inductor current ripple is large

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