Common mode voltage suppression method of non-isolated t-type three-level photovoltaic grid-connected inverter

A common-mode voltage, three-level technology, applied in the field of solar photovoltaic power generation, can solve the problems of conduction and radiation interference, increase of harmonics and losses of incoming current, endangering the safety of equipment and personnel, etc.

Inactive Publication Date: 2017-08-25
XIAN UNIV OF TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Larger-amplitude common-mode currents may cause conduction and radiation interference, increase harmonics and losses of incoming current, and even endanger the safety of equipment and personnel

Method used

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  • Common mode voltage suppression method of non-isolated t-type three-level photovoltaic grid-connected inverter
  • Common mode voltage suppression method of non-isolated t-type three-level photovoltaic grid-connected inverter
  • Common mode voltage suppression method of non-isolated t-type three-level photovoltaic grid-connected inverter

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Embodiment Construction

[0070] The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0071] Such as figure 1 As shown, the circuit structure of the non-isolated T-type three-level photovoltaic grid-connected inverter includes the first parasitic capacitance C PV1 , the first parasitic capacitance C PV1 One end is connected to the ground, the first parasitic capacitance C PV1 The other end of the photovoltaic array is connected to the output voltage U dc The positive pole of the DC bus capacitor C 1 positive pole of the first switch tube S a1 The collector of the second switch tube S b1 The collector of the third switch tube S c1 The collector; PV array output voltage U dc The negative poles of are respectively connected with the second parasitic capacitance C PV2 One end of the DC bus capacitor C 2 The negative electrode of the fourth switching tube S a4 The emitter of the fifth switch tube S b4 emitter, the sixth ...

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Abstract

The invention discloses a common-mode voltage suppression method of a non-isolated T-type three-level photovoltaic grid-connected inverter, which collects the voltage of the capacitor C1 on the DC bus and the voltage of the capacitor C2 under the DC bus in real time, and obtains the voltage of the capacitor C1 on the DC bus and the voltage of the DC bus. The absolute value of the voltage difference dUdc of the capacitor C2 under the bus bar, by judging whether dUdc>dUref is true, and judging whether it is true, choose to use the large and medium zero vector synthesis method or the large, medium and small vector synthesis method or the large and small zero vector synthesis method for non-isolated T-type Three-level photovoltaic grid-connected inverter for modulation. The invention adopts three kinds of vector synthesis methods to modulate the non-isolated T-type three-level photovoltaic grid-connected inverter, which can not only balance the midpoint potential of the DC side of the three-level inverter, but also suppress the amplitude of the common-mode voltage change and frequency, thereby suppressing the common-mode current of the non-isolated T-type three-level photovoltaic grid-connected inverter, and optimizing the efficiency, volume, weight, and cost of the system.

Description

technical field [0001] The invention belongs to the technical field of solar photovoltaic power generation, and in particular relates to a common-mode voltage suppression method of a non-isolated T-type three-level photovoltaic grid-connected inverter. Background technique [0002] As an inexhaustible clean energy, solar energy has undoubtedly become one of the sustainable green energy sources. Photovoltaic grid-connected inverter is a device used to convert the direct current generated by solar energy into alternating current that meets the grid requirements through DC / AC and then connects to the grid. Its performance not only affects and determines whether the entire photovoltaic grid-connected system is reliable, safe and stable. , efficient operation, but also the main factor determining the life of the entire system. Efficiency and grid-connected current quality are two important indicators for measuring photovoltaic grid-connected inverters. [0003] The output volta...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02M7/483
CPCH02J3/38H02M1/12H02M7/483H02M1/0048H02M1/123Y02B70/10
Inventor 孙向东来璐安少亮任碧莹
Owner XIAN UNIV OF TECH
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