Virtual synchronous generator system applied to photovoltaic power station and control method

Abstract

The invention provides a virtual synchronous generator system applied to a photovoltaic power station and a control method, which are simple and effective, and are beneficial to engineering application. The system comprises a photovoltaic inverter, a virtual synchronous machine controller and an energy storage converter DC / AC, wherein the photovoltaic inverter is used for realizing a grid-connected power generation function; the virtual synchronous machine controller is directly connected to a dispatching system; the energy storage converter DC / AC is arranged at an alternating current grid-connected point of the photovoltaic inverter or a direct current collection point of a photovoltaic array, is directly connected to the virtual synchronous machine controller and is used as an executionunit to respond to a power command of the virtual synchronous machine controller; the virtual synchronous machine controller and the energy storage converter DC / AC coordinate to realize the functionsof a virtual synchronous generator of the whole photovoltaic power station, and the photovoltaic inverter still runs in a maximum power point tracking (MPPT) mode to realize the grid-connected power generation function; and the virtual synchronous machine controller and the energy storage converter DC / AC independently construct a high-speed communication network in order to realize high-speed mutual transmission of an active / reactive power command between the virtual synchronous machine controller and the energy storage converter DC / AC.

Description

technical field [0001] The invention belongs to the field of electrical engineering, and in particular relates to a power generation system and a control method applied to a photovoltaic power station. Background technique [0002] In recent years, my country's photovoltaic power generation industry has achieved sustained and rapid development. As of the end of 2016, my country's newly installed photovoltaic power generation capacity was 34.54 million kilowatts, and the cumulative installed capacity was 77.42 million kilowatts, ranking first in the world in both new and cumulative installed capacity. Among them, the annual power generation of photovoltaic power plants is 66.2 billion kwh, accounting for 1% of my country's total annual power generation. However, when a large-scale photovoltaic power station is connected to the power system, its dynamic response characteristics and static output characteristics are significantly different from those of conventional synchronou...

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Problems solved by technology

[0003] 1) The ability of dynamic active output control of photovoltaic power plants to suppress power system frequency disturbances tends to weaken, which can easily cause frequency stability problems

[0004] 2) The ability of dynamic reactive power output control of photovoltaic power plants to suppress voltage disturbances in power systems tends to weaken, which can easily lead to voltage stability problems

[0005] 3) The fluctuation and uncertainty of the static output of the photovoltaic power station can easily cause the problem of insufficient power supply of the system;

[0006] The direct consequence of the above problems is large-scale light abandonment, and engineering applications are limited.

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