Three-phase three-level anpc to eliminate common mode current inverter system

Abstract

The invention discloses a three-phase three-level ANPC inverter system for eliminating common mode current. The system includes a DC power supply, a DC side circuit, a three-phase three-level ANPC inverter circuit, a filter circuit and a load. The DC power supply includes the common-mode parasitic capacitance of the DC power supply to the ground, the DC side circuit includes a common-mode inductor, the three-phase three-level ANPC inverter circuit includes the inverter main circuit and two identical support capacitors, and the filter circuit includes three identical Filter inductors, three identical filter capacitors and an inductance pulled back to the midpoint of the DC bus, the load includes three AC buses. The inverter system provided by the present invention has low cost of added auxiliary components and a small occupied volume, and can eliminate the influence of uncertain parasitic capacitance parameters of a DC power supply under high-frequency conditions, thereby realizing effective common-mode current elimination.

Description

technical field [0001] The invention relates to the field of power electronic converters, in particular to a three-phase three-level ANPC elimination common-mode current inverter system. Background technique [0002] In the inverter system, common-mode parasitic capacitance to ground commonly exists in the DC power supply. Uncertain common-mode parasitic capacitance to ground is bound to have an impact on inverter performance, which is especially serious in photovoltaic inverters. The non-isolated photovoltaic grid-connected power generation method without a transformer has quickly gained the attention of scientific researchers and industrial circles in various countries by virtue of its absolute advantages of high change efficiency, small size, light weight and low cost, and has been applied in some European countries. . However, because there is no transformer as isolation, the photovoltaic cells, photovoltaic inverters, and the grid form a common-mode loop through the c...

AI Technical Summary

Problems solved by technology

[0005] 1) When the second common-mode inductor uses a high-permeability magnetic core, the inductor is easily saturated;

[0006] 2) The common-mode parasitic capacitance of the uncertain DC power supply to the ground is not considered, that is, the influence of the common-mode parasitic capacitance of the photovoltaic array to the ground on the common-mode current suppression;

[0007] 3) In order to obtain a good common-mode current suppression effect at low frequencies, the required second common-mode inductance has a large parameter value and a large volume

[0009] 1) This circuit is not suitable for high-frequency inverter circuits;

[0010] 2) The inverter circuit is aimed at two-level circuits and is difficult to apply to three-level circuits;

[0011] 3) The common-mode parasitic capacitance of the uncertain DC power supply to the ground is not considered, that is, the influence of the common-mode parasitic capacitance of the photovoltaic array to the ground on the common-mode current suppression

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