A nine-level inverter

Abstract

The invention provides a nine-level inverter, which comprises two direct current boosting circuits, eight switch tubes, two inductors, six capacitance units and four anti-countercurrent devices, wherein the public end of the fifth capacitance unit and the sixth capacitance unit is connected with the public end of the first capacitance unit and the second capacitance unit; the fifth capacitance unit and the sixth capacitance unit are output filter circuits of the inverter; the public end of the first capacitance unit and the second capacitance unit is the midpoint of a direct current bus. Known from above, in the inverter, the potential of the midpoint of the direct current bus (or the anode or cathode of a direct current power supply) is more than those of the midpoints of the output filter circuits, and the anode or cathode of the direct current bus is not subjected to a leaping voltage with work frequency or high frequency relative to the ground, so the problem of leak current is avoided. In addition, the efficiency is higher due to the nine-level output and the nine-level inverter is suitable for the application fields such as photovoltaic generating.

Description

technical field [0001] The invention relates to the technical field of power electronics, in particular to a nine-level inverter. Background technique [0002] Inverters are used to convert the DC voltage output by the DC power supply into AC voltage, and are widely used in photovoltaic, wind power generation and other fields. However, due to the existence of the parasitic capacitance of the DC power supply (such as a solar panel) to the ground, there may be a problem of leakage current when the inverter is working. The leakage current problem will not only damage the output power quality and reduce the working efficiency of the inverter, but also cause harm to the human body and reduce the reliability of the inverter. [0003] At present, in order to solve the problem of leakage current, inverters with topologies such as H5, H6, and HERIC have appeared, but these inverters are all three-level inverters, so the efficiency is low. Compared with the three-level inverter, the...

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Problems solved by technology

However, due to the parasitic capacitance of the DC power supply (such as solar panels) to the ground, there may be a problem of leakage current when the inverter is working.

The leakage current problem will not only damage the output power quality and reduce the working efficiency of the inverter, but also cause harm to the human body and reduce the reliability of the inverter.

[0003] At present, in order to solve the problem of leakage current, inverters with topologies such as H5, H6, and HERIC have appeared, but these inverters are all three-level inverters, so the efficiency is low.

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