Virtual synchronous generator self-synchronizing control method based on phase difference real-time regulation

Abstract

The present invention provides a virtual synchronous generator self-synchronizing control method based on phase difference real-time regulation, belonging to the new energy electric power conversion technology field. The technical steps comprises: calculating voltage phase difference [Delta][Theta] of two sides of a filtering inductor in a corresponding inverter output power; employing a phase-locked loop (PLL) to collect voltage phase information of two sides of the LC filter inductor; calculating phase angle determination signals Judge=[Delta]-[Theta]o; calculating regulation determination signals x=Judge-[Delta][Theta]; editing a conversion switch logic control module; and constructing an operation mode conversion switch logic. The virtual synchronous generator self-synchronizing control method based on the phase difference real-time regulation calculates phase angle difference corresponding to a target power value in real time, rapidly regulates voltage phase angle difference of two sides of the LC filter inductor and realizes self synchronization with the power grid with no need for power grid phase information and the presynchronization link. The virtual synchronous generator self-synchronizing control method based on the phase difference real-time regulation enhances control of the power grid side to a distributed generation to allow the distributed generation to be better serve the power grid. The virtual synchronization generator employs an uniform inner ring control structure when the virtual synchronization generator performs island / grid-connected operation so as to avoid causing stability problem caused by changing of inner ring control.

Description

technical field [0001] The invention belongs to the technical field of new energy power conversion, and in particular relates to a self-synchronization control method of a virtual synchronous generator based on phase difference real-time adjustment. Background technique [0002] The types and proportions of new energy in the power grid are gradually increasing. Distributed wind power and photovoltaics are often connected to the grid in the form of micro-grids through inverters. Whether they can smoothly switch between grid-connected and off-grid states has become one of the important goals of inverter control. . Due to the lack of inertia of the power system caused by the increase in the number of inverters in recent years, the concept of virtual synchronous generator (VSG) has gradually received attention, and the algorithm for simulating the operating characteristics of synchronous generators has been introduced into the control strategy of the inverter. Make the inverter...

AI Technical Summary

Problems solved by technology

Although there have been discussions on the switching strategy under the VSG control mode, most of the existing strategies for inverter grid connection require a "pre-synchronization" process. The default condition is that the phase of the grid side is known and can be measured

However, in practical applications, there are situations where phase measurement is difficult

Even if the phase information of the power grid can be easily measured, the information must be transmitted from the grid side to the controller, which will increase the delay time, reduce the accuracy of the information, and increase the cost

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