Seven-level inverter circuit and control method thereof, multi-phase inverter and frequency converter

Abstract

The invention relates to the technical field of frequency converters, in particular to a seven-level inverter circuit and a control method thereof, a multi-phase inverter and a frequency converter. The seven-level inverter circuit comprises capacitors C1-C4 and power electronic switches S1-S12, wherein output of seven levels is realized through opening and closing of the power electronic switches. Compared with the seven-level inverter circuit in a related technology, the seven-level inverter circuit has the advantages that a small number of components are used, the components are normal and readily available and the connection structure is simple, so that the topological structure of the seven-level inverter circuit is simplified and the cost of the seven-level inverter circuit is reduced. Since the topological structure of the seven-level topological circuit is simplified in the embodiment of the invention, the cost of the seven-level inverter circuit is reduced; thus the topological structures of the multi-phase inverter and the frequency converter including a plurality of seven-level inverter circuits are simple and the cost is reduced.

Description

technical field [0001] The invention relates to the technical field of frequency converters, in particular to a seven-level inverter circuit and a control method thereof, a multi-phase inverter and a frequency converter. Background technique [0002] Inverter (Variable-frequency Drive, VFD) is a power control device that uses frequency conversion technology and microelectronics technology to control AC motors by changing the frequency of the motor's operating power supply. The frequency converter is mainly composed of rectification (AC to DC), filter, inverter (DC to AC), braking unit, drive unit, detection unit, micro-processing unit, etc. As a basic electrical equipment, it has been widely used. [0003] Frequency converters (including inverters, the same below) are divided into two types: voltage source type and current source type. Voltage source inverters are divided into 2-level, 3-level, 5-level and more levels according to the number of levels that can be output by...

AI Technical Summary

Problems solved by technology

This structure requires too many capacitors, and the voltage and capacity of each capacitor in the figure are different, the volume is too large, and the cost is too high

[0009] To sum up, it can be seen that the current common DC bus multi-level inverter has a topology structure of 7 levels that is too complicated, the cost and volume are too high, and the practicability is low

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