One-phase five-level inverter

Abstract

The invention discloses a one-phase five-level inverter. The one-phase five-level inverter comprises a common ground type three-level switching circuit, a filter circuit and a power frequency inversion circuit. For being realized specifically, the inverter comprises six power switches from S1 to S6, two diodes from D1 to D2, and a one-phase output filter F. The output of the inverter is five levels, and the inverter has the advantages of being high in inversion efficiency and reliability and simple in control mode. Meanwhile, through the voltage clamp mode, the inverter can eliminate high-frequency common mode current danger in a non-isolated type grid-connected inverter system effectively. Thus, the inverter is especially suitable for being applied to a non-isolated type photovoltaic grid-connected system.

Description

technical field [0001] The invention belongs to the technical field of power electronics, and in particular relates to a single-phase five-level inverter. Background technique [0002] With the intensification of the global energy crisis and environmental problems, vigorously developing renewable clean energy has become the focus of energy development in countries all over the world. Photovoltaic power generation has shown good development prospects due to its rich resources and wide distribution. However, photovoltaic power generation has problems such as high power generation cost and low energy density. Therefore, how to reduce costs and improve energy conversion efficiency has become a challenging engineering topic for photovoltaic power generation systems. [0003] In the photovoltaic grid-connected system, the photovoltaic grid-connected inverter is responsible for converting the DC power generated by the photovoltaic cell array into AC power, and then delivering it t...

AI Technical Summary

Problems solved by technology

However, there is always a high-frequency voltage disturbance in the voltage between the neutral line of the power grid and the negative pole of the DC input in this circuit. This high-frequency voltage will generate a large high-frequency common-mode current on the parasitic capacitance of the photovoltaic cell. Theoretical analysis and experiments prove that This five-level inverter solution is not suitable for non-isolated photovoltaic grid-connected systems

[0007] The solutions proposed by the above-mentioned related prior art may have problems such as high required bus voltage, poor high-frequency common-mode current suppression effect, or low conversion efficiency, etc.

Images