Coupled quasi-Z-source direct-current converter

Abstract

The invention discloses a coupled quasi-Z-source direct-current converter. The converter comprises two independent direct-current capacitors, a direct-current half bridge and a three-winding coupling inductor. The direct-current half bridge is composed of two switching tubes. The clamping effect of the diodes is realized by utilizing the electromotive force effect of the two coupling inductors in the quasi-Z-source network, the diodes in the commutation loop are removed, and the circuit reliability is improved. The electromotive force of the output end coupling inductor is utilized to realize mutual abutting between the electromotive force of the output inductor and the voltage source of the output end when the switching tube is directly connected, thereby preventing voltage mutation at two ends of the output inductor and preventing out-of-control caused by overlarge ripple of the output current. By utilizing the effect of the coupling inductance electromotive force of the output end, when the switching tube performs complementary voltage reduction work, the coupling of the inductance enables the equivalent inductance of the output end to be larger, the corresponding output current ripple to be smaller, the design of an output side filter is reduced, and the system efficiency and the power density are improved.

Description

technical field [0001] The invention relates to a converter topology design in the field of power electronics, in particular to a coupled quasi-Z source DC converter. Background technique [0002] Since traditional voltage source converters and current source converters cannot be step-up / step-down converters at the same time, many topologies of Z-source converters or quasi-Z-source converters have been proposed in the industry. At present, the research in the quasi-Z source converter field mainly includes: the control of the quasi-Z source converter, the gain of the quasi-Z source converter, and the combination of the advantages of the quasi-Z source converter and other topologies. [0003] A conventional quasi-Z source DC converter includes two independent inductors, two independent capacitors, a diode, a DC half-bridge, and an output independent inductor. Two independent inductors and two independent capacitors are mainly responsible for the energy transfer of the half-br...

AI Technical Summary

Problems solved by technology

[0004] Conventional quasi-Z source DC converters still have the following problems: 1. In order to ensure the commutation circuit, clamp diodes are used for unidirectional isolation, which increases the loss of power electronic devices; 2. In medium and high-power high-frequency circuits, the clamp The reliability of diode isolation is very low; 3. In DC conversion, the quasi-Z source converter does not aim at how to offset the influence of the voltage source on the output side in the direct-passing interval of the switch tube, limiting its application in the field of current source; 4. Power electronics The number of devices increases, and the cost of corresponding circuit integration is extremely high

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