Control method and device in photovoltaic power generation grid-connected system

A photovoltaic power generation and control method technology, applied in the direction of photovoltaic power generation, single-net parallel feeding arrangement, etc., can solve the problems that cannot really meet the requirements of the power system

Active Publication Date: 2019-12-17
THE HONG KONG POLYTECHNIC UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The control of reactive power in the above-mentioned patent application is simple and cannot really meet the requirements of the power system

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  • Control method and device in photovoltaic power generation grid-connected system
  • Control method and device in photovoltaic power generation grid-connected system
  • Control method and device in photovoltaic power generation grid-connected system

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Embodiment Construction

[0110] Embodiments of the present application will be described in detail below. It should be noted that the embodiments described here are for illustration only, and are not intended to limit the scope of the present application.

[0111] The future power grid has two salient features: one is the decentralized structure of microgrid integration, and the other is poor stability due to the high volatility and intermittency of renewable energy and small inertia.

[0112] Take solar systems as an example. In the past, distributed solar systems were free to disconnect from the main grid in the event of a low voltage failure. However, with the increasing popularity of solar energy systems in recent years, low-voltage ride-through (Low-Voltage-Ride-Through, LVRT) has become a necessary capability required by the distribution network to help photovoltaic (Photovoltaic, PV) The inverter survives the fault. Early grid regulations (such as IEEE 1547-2003) required that photovoltaic ge...

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Abstract

The invention relates to a low-voltage ride-through control method and device in a photovoltaic power generation grid-connected system. The photovoltaic power generation grid-connected system comprises photovoltaic power generation equipment; a DC-DC converter, which is connected to the photovoltaic power generation equipment; an inverter, which is connected to the DC-DC converter through a DC link capacitor; and transformation isolation equipment, which is connected to the inverter through a common grid-connected point and is connected to a main power grid. The method comprises the followingsteps: when detecting that the voltage drop of the common grid-connected point exceeds a preset threshold value, calculating an active component and a reactive component of the output current of the inverter according to the voltage drop degree and low-voltage ride-through requirements specified by a corresponding power grid, and feeding the calculated active component and the reactive component of the current to the inverter, wherein the low-voltage ride-through requirements comprise at least one of the longest time when the inverter needs to be kept networked and reactive current proportionneeding to be provided when the voltage drop of the common grid-connected point exceeds the preset threshold value. The device and method can keep higher active energy output in a low-voltage fault ofthe power grid.

Description

technical field [0001] The present application relates to the field of renewable energy power generation, and more specifically, to a control method and device in a grid-connected photovoltaic power generation system. Background technique [0002] Solar energy, water energy, wind energy, biomass energy, wave energy, tidal energy, ocean temperature difference energy, geothermal energy and other energy sources are inexhaustible and environmentally friendly energy sources, and their large-scale production and grid connection are developing rapidly. It has received strong support from national policies and resources. Taking solar power generation as an example, at first, when the voltage of the public grid-connected point drops due to a fault, the grid-connected photovoltaic inverter will directly run off-grid due to the activation of the protection device. However, the simple removal of photovoltaic devices will further reduce the active power and further reduce the grid volta...

Claims

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Application Information

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IPC IPC(8): H02J3/38
CPCY02E10/56
Inventor 何宇飞许昭
Owner THE HONG KONG POLYTECHNIC UNIV
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