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LCL non-isolation type grid-connected inverter system

An inverter, non-isolated technology, applied in the field of LCL non-isolated grid-connected inverter system, to achieve the effects of easy implementation, improved grid current quality, and reduced voltage stress

Inactive Publication Date: 2016-10-19
NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, the low leakage current solution for non-isolated grid-connected inverters is still a problem worth exploring

Method used

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  • LCL non-isolation type grid-connected inverter system
  • LCL non-isolation type grid-connected inverter system
  • LCL non-isolation type grid-connected inverter system

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] The following is a detailed description of the LCL non-isolated grid-connected inverter system of the HERIC circuit combined with the inverter, such as figure 2 The shown HERIC circuit includes a first bridge arm, a second bridge arm and a switch unit; the switch unit includes a switch tube Q 5 and Q 6 ; The above switch tube Q 5 The emitter is connected to the midpoint A of the first bridge arm, and the above-mentioned switching tube Q 6 The emitter of the second bridge arm is connected to point B, the switch tube Q 5 The collector and switch tube Q 6 connected to the collector; the inverter is connected to the filter, specifically, the inverter side inductance is divided into two identical inductances connected in parallel; the upper inverter side inductance is connected to the switching tube Q 5 The emitter, the lower inverter side inductor is connected to the switching tube Q 6 the emitter.

[0026] In this embodiment, the LCL filter capacitor C f1 with C f...

Embodiment 2

[0038] Such as image 3 Shown is the structure diagram of the LCL non-isolated grid-connected inverter system combined with the H5 topology, including the first bridge arm, the second bridge arm and the switching unit; the switching unit includes the switching tube Q 5 ; The switching tube Q 5 The emitter of the inverter is connected to the upper ends of the two bridge arms, and the collector is connected to the positive end of the photovoltaic panel; the inverter topology is connected to the filter, specifically, the inverter side inductance is divided into two identical inductances connected in parallel, The upper inverter side inductance is connected to point A of the first bridge arm, and the lower inverter side inductance is connected to point B of the second bridge arm; the filter capacitor C of the LCL type filter f1 with C f2 Node H 1 Connect with point O.

Embodiment 3

[0040] Such as Figure 4 Shown is the structure diagram of the LCL non-isolated grid-connected inverter system combined with the H6 topology, including the first bridge arm, the second bridge arm and the diode D 1 、D 2 ; The first bridge arm includes a switching tube Q 1 , Q 3 and Q 5 ; The second bridge arm includes a switching tube Q 2 , Q 4 and Q 6 ; The diode D 1 The anode and cathode of the switch are respectively connected to the switch Q 4 the emitter and Q 3 collector; the diode D 2 The anode and cathode of the switch are respectively connected to the switch Q 3 the emitter and Q 4 The collector of the inverter; the inverter topology is connected to the filter, specifically, the inverter side inductance is divided into two identical inductances connected in parallel, the upper inverter side inductance is connected to point A of the first bridge arm, and the lower inverter side is connected to point A of the first bridge arm. The inductance on the transforme...

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Abstract

The invention discloses an LCL non-isolated grid-connected inverter system, which includes an inverter, a photovoltaic cell, an LCL filter, and a public power grid; the photovoltaic cell includes a photovoltaic cell panel and a DC bus filter capacitor; the DC The bus filter capacitor includes a first DC bus filter capacitor and a second DC bus filter capacitor connected in series; the DC bus filter capacitor is connected in parallel with the photovoltaic panel; the LCL type filter includes an inverter side inductor, a grid side inductor and The filter capacitor, the inductance on the inverter side is divided into two identical inductances connected in parallel, respectively connected to the middle point of the inverter bridge arm; the inductance on the grid side is divided into two identical inductances connected in parallel, connected to both ends of the inductance on the inverter side , and connected to the public power grid; the filter capacitor is connected between the inverter side inductance and the grid side inductance, which includes a first filter capacitor and a second filter capacitor connected in series; the middle point of the two filter capacitors is connected to the DC bus input end.

Description

technical field [0001] The invention relates to an LCL non-isolated grid-connected inverter system, which belongs to the technical field of power electronic conversion and control. Background technique [0002] Non-isolated grid-connected inverters have the advantages of high efficiency and low cost, and have become the current development trend. Due to the large area of ​​photovoltaic panels, there is a large parasitic capacitance between the photovoltaic array and the ground. In the isolated scheme, there is no physical connection between the photovoltaic cells and the grid, so there is no leakage current problem; , Power grid, and the earth form a high-frequency leakage current loop. The generation of high-frequency leakage current will bring conduction and radiation interference, increase the harmonics and loss of the incoming current, and even endanger the safety of equipment and personnel. According to the German standard DINVDE0126-1-1, when the instantaneous ground...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02M7/48H02M7/5387H02M1/32
CPCY02E10/56
Inventor 汤雨柏杨徐飞
Owner NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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