Bidirectional cascade voltage-increasing and decreasing direct current-alternating current converter

Abstract

The invention relates to a bidirectional cascade voltage-increasing and decreasing direct current-alternating current converter, belonging to the technical field of power electronics. The converter comprises a voltage decreasing level circuit, a direct current bus inductor, a voltage increasing level circuit and a control circuit. The voltage decreasing level circuit forms an H bridge structure by two fully-controlled devices and two diodes, so that a bipolar alternating current voltage can be generated on a direct current bus; and the voltage increasing level circuit forms an H bridge structure by four unidirectional fully-controlled switch devices, so that a bipolar alternating current voltage can be generated on an output end. In the converter, the control circuit is used for controlling the switch period mean value of the direct current bus current to be constant by properly changing the respective conducting mode of the voltage decreasing level circuit and the voltage increasing level circuit, so that the converter is guaranteed to have the voltage-increasing and decreasing capabilities, the bidirectional energy flow capability, and the direct current-alternating current converting capability.

Description

A bidirectional cascaded buck-boost DC-AC converter technical field The invention relates to a bidirectional cascaded buck-boost DC-AC converter, which belongs to the technical field of power electronics. Background technique Today, DC-AC converters are used in a wide range of commercial and industrial applications. For example, DC-AC converters are used in electric vehicle drive systems, energy storage systems, renewable energy generation systems, and more. At present, traditional voltage source converters occupy a large market share in these applications. Because the traditional voltage source converter is essentially based on the step-down DC-DC conversion circuit topology, this type of DC-AC converter can only operate in the state of step-down output. However, in many applications, such as electric vehicles, fuel cells, and photovoltaic power generation systems, DC-AC converters are required to have both boost and step-down output capabilities. Not only that, but in...

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Problems solved by technology

This solution can also overcome the cost and efficiency deficiencies of traditional boost inverters, but due to the inherent problem of insufficient control freedom in the boost or buck-boost DC-DC conversion circuit, in AC applications due to the large operating point changes, the control of the system is also very difficult

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