Cascaded multi-mode photovoltaic grid-connected inverter and modulation method thereof

An inverter and multi-mode technology, which is applied in the field of cascaded multi-mode photovoltaic grid-connected inverters and their modulation, can solve the problems of large inverter loss and low quality of inverter output power, and reduce the Loss, broaden the scope of grid connection, reduce the effect of the overall loss

An inverter and multi-mode technology, which is applied in the field of cascaded multi-mode photovoltaic grid-connected inverters and their modulation, can solve the problems of large inverter loss and low quality of inverter output power, and reduce the Loss, broaden the scope of grid connection, reduce the effect of the overall loss

CN110138005AActive Publication Date: 2019-08-16ZHENGZHOU UNIV
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  • Cascaded multi-mode photovoltaic grid-connected inverter and modulation method thereof
  • Cascaded multi-mode photovoltaic grid-connected inverter and modulation method thereof
  • Cascaded multi-mode photovoltaic grid-connected inverter and modulation method thereof

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Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0031] Inverter structure embodiment

[0032] Such as figure 1Shown is a schematic diagram of the topology structure of this embodiment, including capacitor strings 11, DC side switch groups 21, DC side switch groups 22, bridge arm switch groups 31, bridge arm switch groups 32, capacitor strings 12, and DC side switch groups 23. DC side switch group 24, bridge arm switch group 33, bridge arm switch group 34, bidirectional switch group 41.

[0033] Specifically, the capacitor string 11 is composed of two groups of equivalent capacitors C 1 and C 2 Composed in series, with photovoltaic array output unit U dc1 Parallel connection; DC side switch group 21 consists of switch tube S 1 and diode D 1 Constituted in reverse series; the DC side switch group 22 is composed of a switch tube S 2 and diode D 2 Constituted in reverse series; bridge arm switch group 31 is composed of switch tube S 3 and S 5 Constituted in series in the forward direction, and respectively anti-paralle...

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Abstract

The invention relates to a cascaded multi-mode photovoltaic grid-connected inverter and a modulation method thereof, belonging to the field of power conversion and new energy distributed grid-connected power generation. The modulation strategy can be adjusted and the working state of the switch can be adjusted to a nine-level, five-level or three-level mode according to the actual working condition, so as to optimize the quality of output waveform and reduce the overall loss. When the input power of the DC side is low, a nine-level or five-level output mode is adopted to improve the waveform quality of the grid-connection current and widen the grid-connection range. When the input power of the DC side is high, a three-level output mode is adopted to reduce the loss of the inverter and improve the efficiency of the system. Both the waveform quality of the current injected by the photovoltaic grid-connected inverter into the grid and the loss of the inverter are taken into account, whichis beneficial to improving the quality of the grid-connected power of the system and reducing the loss in the inverting process.

Description

technical field [0001] The invention relates to a cascaded multi-mode photovoltaic grid-connected inverter and a modulation method thereof, belonging to the field of electric energy conversion and new energy distributed grid-connected power generation. Background technique [0002] Energy is the material basis for the survival and development of human beings. With the development and progress of science and technology, the material life of human society has been greatly enriched, and the consumption and demand for energy are also increasing. Among many renewable energy sources, solar energy is developing rapidly due to its many advantages such as wide sources, abundant reserves, green and clean, and not restricted by the geographical environment. Photovoltaic power generation technology is an important means to effectively utilize solar energy, and it is also one of the important pillars of future electricity production. In the photovoltaic power generation system, the inve...

Claims

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Application Information

Patent Timeline
16 Aug 2019
Publication
CN110138005A
IPC
H02J3/38; H02M7/5387; H02M7/483
CPC
H02J3/383; H02M7/53871; H02M7/483; H02M1/0054; H02M7/4835; Y02E10/56; Y02B70/10
Inventors
王要强; 杜冠宇