Novel voltage type multi-level inverter

Abstract

The invention discloses a novel voltage type multi-level inverter. When the number of input power sources is expanded from n to n+1, the number of power switch tubes is increased from 2n+2 to 2n+4, wherein n is an integer not smaller than 1, similarly hereinafter; and when voltage of the input power sources is the same, the number of output levels changes from 2n+1 to 2n+3, namely when one power source is added, two power switch tubes and two levels are added. Compared with an existing classic multi-level inverter, the novel voltage type multi-level inverter enables the used power switch tubes and isolation driving to be less, a clamping diode and a flying capacitor and the like are not required, part of the power switch tubes are be in a low-frequency working state, on-off times is little, and switching loss is reduced. According to the novel voltage type multi-level inverter, one-dimensional space vector modulation is adopted, a modulation method is simple, the computing speed is quick, redundant vectors are reasonably utilized, quality of electric energy output by the inverter is improved, and the novel inverter meets the technical requirements of renewable energy and new energy power generation and is suitable for multi-input power source occasions.

Description

technical field [0001] The invention relates to an inverter in the field of DC-AC converters of power electronics technology, in particular to a multi-level inverter with multiple input power supply voltages. Background technique [0002] Inverter refers to a power electronic converter that converts DC power into AC power through the on and off functions of semiconductor power switching devices. Its function is to compare the quality of power obtained from batteries, solar cells, fuel cells, etc. The poor DC raw power is transformed into AC power with high power quality and meeting the voltage and frequency requirements of the user load. The multi-level inverter fits the output waveform by outputting multiple levels, reduces the distortion of the output waveform, and reduces the voltage stress of the power switch tube. Therefore, the multi-level inverter is widely used in medium and large capacity applications. Traditional midpoint clamped <npc>multilevel inverters, ...

AI Technical Summary

Problems solved by technology

[0003] In order to solve the problem of large number of power switch tubes and few levels in the traditional voltage-type multi-level inverter, the present invention provides a new type of voltage-type multi-level inverter, which is different from the existing classic multi-level inverter Compared with the same number of output levels, the new voltage-type multilevel inverter uses less power switch tubes and less isolated drives, and does not need clamping diodes, flying capacitors, etc., and some power switch tubes are in low-frequency working conditions. , fewer switching times, reducing switching losses

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