Inverter circuit, inverter and photovoltaic power generation system

Abstract

The invention discloses an inverter circuit that can be applied to an inverter such as a photovoltaic inverter. An embodiment of the invention further provides an inverter and a photovoltaic power generation system. Both the inverter and the inverter in the photovoltaic power generation system comprise inverter circuits disclosed in the invention. According to the inverter circuit, based on an HERIC topology inverter circuit structure, by the bridging of a third capacitor and a fourth capacitor on buses on a first vertical bridge and a second vertical bridge, in the process of converting the inverter circuit from a turn-on phase to a follow current phase, the third capacitor and the fourth capacitor can stabilize a voltage fluctuation in the HERIC topology due to different turn-off speeds of a switching tube, therefore, the resonance problem caused by the voltage fluctuation is prevented, the problem of the resonance interference is solved, the electro magnetic compatibility (EMC) of equipment and the system which can work normally in an electromagnetic environment and do not form electromagnetic disturbance which cannot be borne by any item in an environment can satisfy the requirements of EMC related standards.

Description

technical field [0001] The present application relates to the technical field of voltage conversion, in particular to an inverter circuit, an inverter and a photovoltaic power generation system. Background technique [0002] As a renewable clean energy, the photovoltaic power generation industry has developed rapidly in recent years. A photovoltaic power generation system includes multiple components such as photovoltaic modules, inverters, transformers, and cables. The inverter is the core component of the energy conversion of the photovoltaic power generation system, which plays a role in converting the direct current output by the photovoltaic modules into alternating current available for the grid. effect. At the same time, inverters are also widely used in other systems that need to convert DC power into AC power. [0003] Highly efficient reliable inverter concept, HERIC, is a highly efficient and reliable inverter concept. The HERIC topology based on this concept ha...

AI Technical Summary

Problems solved by technology

[0003] Highly efficient reliable inverter concept, HERIC, is a highly efficient and reliable inverter concept. The HERIC topology based on this concept has been widely used in photovoltaic inverter products due to its own low-cost characteristics, such as figure 1 As shown, in the prior art, a first vertical bridge and a second vertical bridge are included in the HERIC topology, wherein the two ends of the first vertical bridge are respectively connected to the first switching tube and the second switching tube, and the two ends of the second vertical bridge The two ends are respectively connected with the third switching tube and the fourth switching tube. In the first half cycle of the inverter output, the first switching tube and the fourth switching tube are closed. When entering the freewheeling stage, at this time, the first switching tube and the fourth switching tube are closed. The switch tubes are disconnected at the same time. In actual work, the disconnection speed of the first switch tube and the fourth switch tube cannot be kept completely consistent. For example, the disconnection speed of the fourth switch tube is faster than that of the first switch tube. At this time, the bus, The voltage on the first vertical bridge and the second vertical bridge will increase, and after the first switching tube is turned off, the voltage will drop again, and resonance will occur in this process

Thus affecting the ability of equipment and systems to work normally in their electromagnetic environment without causing unacceptable electromagnetic disturbance (electro magnetic compatibility, EMC) to anything in the environment, causing the results of EMC conduction and radiation test items to exceed the standard

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