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A dual-buck grid-connected inverter that can eliminate common-mode leakage current

A leakage current, double step-down technology, applied in the direction of converting AC power input to DC power output, electrical components, photovoltaic power generation, etc., can solve the problems of high price, reduce power density, increase inverter cost, etc., and achieve high power density, improved reliability, and the effects of eliminating common-mode leakage current

Inactive Publication Date: 2019-02-01
SOUTHWEST PETROLEUM UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0033] The purpose of the present invention is to overcome the deficiencies of the prior art, to provide a dual step-down grid-connected inverter that can eliminate the common-mode leakage current, and to solve the traditional DFGI’s requirement of leakage current, which requires the addition of expensive large-volume filter capacitors. The problem of increasing inverter cost and reducing power density

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  • A dual-buck grid-connected inverter that can eliminate common-mode leakage current
  • A dual-buck grid-connected inverter that can eliminate common-mode leakage current
  • A dual-buck grid-connected inverter that can eliminate common-mode leakage current

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Embodiment Construction

[0071] Further describe the technical scheme of the present invention in detail below in conjunction with accompanying drawing:

[0072] It can be seen from the background technology that the root cause of the common-mode leakage current in the traditional DFGI is that the effective common-mode voltages of the positive half-cycle mode I and mode II are different, and the high frequency changes with the transition between mode I and mode II. To solve this problem, this embodiment does not have a filter capacitor C f In the case of DFGI, a switch tube S is connected in series at the positive end of the DC power supply of the traditional DFGI 5 ,Such as Figure 5 shown.

[0073] Dual-buck grid-tie inverter to eliminate common-mode leakage current, including freewheeling diode D 1 、D 2 、D 3 、D 4 , switch tube S 1 , S 2 , S 3 , S 4 , S 5 , filter inductance L 1 , L 2 , L g , where L g is the grid side filter inductance;

[0074] Photovoltaic DC input voltage u in T...

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Abstract

The invention discloses a double step-down grid-connected inverter capable of eliminating common-mode leakage current. The positive end of the photovoltaic DC input voltage uin is connected to S5, the other end of S5 is connected to D1, D2, S3, and S4 respectively, the positive end of D1 is connected to S1 and L1 respectively, the positive end of D2 is connected to S2 and L2 respectively, and S3 One end of D3 is connected to the positive end of D3, the negative end of D3 is connected to one end of L1 and Lg respectively, the other end of Lg is connected to one end of grid voltage ug, S4 is connected to the positive end of D4, the other end of ug, L2 The other end and the negative end of D4 are grounded, and S1 and S2 are connected to the negative end of uin. Compared with the traditional double step-down grid-connected inverter with filter capacitors, the invention has lower leakage current without filter capacitors.

Description

technical field [0001] The invention relates to the field of photovoltaic grid-connected inverters, in particular to a double-buck grid-connected inverter capable of eliminating common-mode leakage current. Background technique [0002] Grid-connected Inverter (GCI), as the core power conversion device of photovoltaic power generation equipment, requires GCI to have high power quality and reliability [1-3] . The traditional bridge GCI needs to set a dead time for the switching tubes of the same bridge arm to avoid bridge arm shoot-through, but the introduction of the dead time will increase the harmonics of the grid-connected current and reduce its power quality [4-5] . Non-isolated photovoltaic grid-connected inverter (NPGCI) has the advantages of small size, low cost and high efficiency. [6-8] . However, since there is no isolation transformer between the NPGCI photovoltaic DC side and the AC side, and there is a parasitic capacitance between the DC side and the ground...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02M7/5387H02M1/12
CPCH02M1/12H02M7/5387H02M1/0054H02M1/123Y02B70/10Y02E10/56
Inventor 代云中赵万明官子超张荣飞蒋林钟新梅谷雪琴施星瑞曾蕊周春华
Owner SOUTHWEST PETROLEUM UNIV