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Two-stage non-isolated full-bridge grid-connected inverter

A non-isolated, inverter technology, applied in the direction of converting AC power input to DC power output, output power conversion devices, electrical components, etc., can solve problems such as leakage current

Active Publication Date: 2015-12-23
HOHAI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this method requires two DC bus capacitor branches, and the withstand voltage of the second DC bus capacitor must be greater than the peak value of the grid voltage
On the other hand, the topology of the grid-connected inverter in this scheme is a traditional bridge inverter, so when using unipolar SPWM modulation, there is a problem of leakage current, and the device voltage stress of the bridge inverter is the second DC bus capacitor voltage

Method used

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  • Two-stage non-isolated full-bridge grid-connected inverter
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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0082] The two-stage non-isolated full-bridge grid-connected inverter described in Embodiment 1 includes six working modes:

[0083] Mode 1: The first power switch tube S 1 , the fourth power switch tube S 4 and the fifth power switch tube S 5 turn on, the other power switch tubes are off, and the incoming current flows through the first power switch tube in turn S 1 , the first filter inductor L f1 , power grid u g , the fourth power switch tube S 4 . third power diode D 3 The voltage stress for the second DC link capacitor C dc2 voltage value.

[0084] Mode 2: The fourth power switch tube S 4 and the fifth power switch tube S 5 turn on, the other power switch tubes are off, and the grid current flows through the fifth power switch tube in turn S 5 , the third power diode D 3 , the first filter inductor L f1 , power grid u g , the fourth power switch tube S 4 . first power diode D 1 The voltage stress for the first DC link capacitor C dc1 v...

Embodiment 2

[0098] The two-stage non-isolated full-bridge grid-connected inverter described in Embodiment 2 includes six working modes:

[0099] Mode 1: The first power switch tube S 1 , the fourth power switch tube S 4 and the fifth power switch tube S 5 turn on, the other power switch tubes are off, and the incoming current flows through the first power switch tube in turn S 1 , the fifth power switch tube S 5 , the first filter inductor L f1 , power grid u g , the fourth power switch tube S 4 .

[0100] Mode 2: The fourth power switch tube S 4 and the fifth power switch tube S 5 is turned on, the other power switches are turned off, and the incoming current flows through the third power diode in turn D 3 , the fifth power switch tube S 5 , the first filter inductor L f1 , power grid u g , the fourth power switch tube S 4 ; The first power switch tube S 1 The voltage stress for the second DC link capacitor C dc2 voltage value.

[0101] Mode 3: The fourth...

Embodiment 3

[0124] The two-stage non-isolated full-bridge grid-connected inverter described in Embodiment 3 includes six working modes:

[0125] Mode 1: The first power switch tube S 1 , the fourth power switch tube S 4 and the fifth power switch tube S 5 turn on, the other power switch tubes are off, and the grid current flows through the fourth power switch tube in turn S 4 , power grid u g , the first filter inductor L f1 , the first power switch tube S 1 .

[0126] Mode 2: The fourth power switch tube S 4 and the fifth power switch tube S 5 turn on, the other power switch tubes are off, and the grid current flows through the fourth power switch tube in turn S 4 , power grid u g , the first filter inductor L f1 , the third power diode D 3 , the fifth power switch tube S 5 .

[0127] Mode 3: The fourth power switch tube S 4 turn on, the other power switch tubes are off, and the grid current flows through the fourth power switch tube in turn S 4 , power gri...

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Abstract

The invention discloses a two-stage non-isolated full-bridge grid-connected inverter, which comprises a first direct-current bus capacitor, a second direct-current bus capacitor, a direct-current power conversion circuit, a first power switch tube, a second power switch tube, a third power switch tube, a fourth power switch tube, a fifth power switch tube, a sixth power switch tube, a first power diode, a second power diode, a third power diode, a fourth power diode, a first filter inductor, a second filter inductor and a filter capacitor, wherein the power switch tubes and the power diodes have a plurality of structures and connection modes. The two-stage non-isolated full-bridge grid-connected inverter has the characteristic that a series form is adopted by partial power switch tubes and power diodes, so that the voltage stress of a power device is only equal to the voltage of the first direct-current bus capacitor or the voltage of the second direct-current bus capacitor. The voltage stress of the power switch tubes and the power diodes is reduced, so that the cost is reduced; the efficiency is improved; and the problems in the prior art are solved.

Description

technical field [0001] The invention relates to a two-stage non-isolated full-bridge grid-connected inverter, which belongs to the technical field of power electronic converters. Background technique [0002] With the increasingly severe energy crisis and environmental pollution, new energy power generation technologies such as solar energy, wind energy, and fuel cells have become the focus of attention and research around the world. According to whether the new energy power generation system is connected to the public grid, it can be divided into two modes: grid-connected operation and independent operation. Among them, grid-connected operation is the most common way of new energy power generation application, and grid-connected inverter is a key component in the new energy grid-connected system, and it is of great significance to improve its conversion efficiency. [0003] In the traditional two-stage photovoltaic grid-connected inverter, the output power of the photovolt...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02M7/5387
Inventor 张犁吴红飞赵晋泉
Owner HOHAI UNIV
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