Micro-grid inverter control method based on improved virtual synchronous generator

Abstract

The invention provides a micro-grid inverter control method based on an improved virtual synchronous generator, which relates to the technical field of micro-grid inverter control. The method includesthe following steps: collecting the output parameters of a micro-grid inverter, converting the output parameters into corresponding values under a d-q coordinate system, and obtaining a mathematicalmodel of the micro-grid inverter under the d-q coordinate system; calculating the active power and reactive power output by the micro-grid inverter; using a virtual speed governor and a virtual excitation regulator to obtain the virtual mechanical power and terminal voltage of a virtual synchronous generator; obtaining a reference voltage through an improved VSG rotational inertia control algorithm; and finally, using the obtained reference voltage as the input of an improved voltage and current loop, and outputting a pulse width modulation signal to drive a power device of the micro-grid inverter so as to control the micro-grid inverter. The micro-grid inverter control method based on an improved virtual synchronous generator provided by the invention enables a micro-grid inverter under islanded operation conditions to have the ability to support the grid voltage stability and make fast frequency response.

Description

technical field [0001] The invention relates to the technical field of microgrid inverter control, in particular to a microgrid inverter control method based on an improved virtual synchronous generator. Background technique [0002] As a buffer link between distributed power sources and the grid, the microgrid can solve the problems of low predictability and instability caused by the high proportion of new energy sources entering the grid, and can improve the power quality and reliability of the grid. When a line fault occurs in the power grid, the microgrid inverter can operate in an off-grid mode (island operation). In the island operation state, the inverter is controlled by the virtual synchronous generator technology (Virtual synchronous generator, VSG), which has the advantages of large inertia and large output impedance. Although the traditional virtual synchronous generator control can make the power electronic interface type inverter have the characteristics of a ...

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Problems solved by technology

Although the traditional virtual synchronous generator control can make the power electronic interface type inverter have the characteristics of a generator, support the stability of the voltage and frequency of the microgrid, provide inertial buffer energy for the microgrid, and improve the reliability of the inverter power supply, but it cannot take into account The dynamic adjustment performance of power adjustment and frequency adjustment makes the anti-interference of the inverter output frequency poor; and the distortion rate of the output current of the microgrid inverter is large

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