Three-phase three-level ANPC common-mode current elimination inverter system

Abstract

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