Buck-boost tri-level inverter based on Zeta

Abstract

The invention discloses a buck-boost tri-level inverter based on Zeta. The buck-boost tri-level inverter based on Zeta is formed through output-series of two improved Zeta circuits which can realize buck-boost output to realize DC / AC single-phase inversion. The basic function of the inverter is to realize buck-boost inversion, and when the input DC voltage is lower or is large in the changing range, the double Zeta buck-boost tri-level inverter can still complete the inversion function normally and can realize AC output with stable points. The buck-boost tri-level inverter based on Zeta has the advantages of being high in reliability, being simple in circuit structure, being easy for control, being high in efficiency, reducing the zero-crossing distortion of the output voltage, being long in service life, having good harmonic wave frequency spectrum, being low in the voltage stress borne by switch tubes, and being low in the loss of switches.

Description

technical field [0001] The invention relates to the field of electric energy conversion, in particular to a multi-level inverter which can be expanded to output more levels and can realize both step-up and step-down. Background technique [0002] The multi-level inverter obtains more output levels by changing its own structure, and at the same time, the voltage and current stress borne by its switch tubes are also improved. Under the condition that the switching tubes bear the same voltage and current level and work at the same switching frequency, compared with the two-level inverter, the output voltage of the multi-level inverter is closer to the sine wave, and the harmonic characteristics are better . Therefore, in high-power applications, multi-level inverters are receiving more and more attention. The main application scope includes high-voltage and high-power frequency conversion speed regulation, reactive power compensation of power system and active filter device, ...

AI Technical Summary

Problems solved by technology

However, the output AC voltage on the inverter side of the traditional voltage-type multilevel inverter topology is lower than the input voltage on the DC side, that is, it is in a step-down output state; in the field of new energy power generation, such as wind power generation, solar power generation, etc. Influenced by environmental factors such as wind strength, light intensity, and battery surface temperature, the input voltage varies greatly, and the output side needs a relatively stable AC output whether it is connected to the grid or connected to the load.

This feature limits the application of multi-level inverters in new energy applications

Using the traditional multi-level inverter will no longer meet the requirement of step-down and step-down to produce a relatively stable AC output

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