Active oscillation suppression method for grid-connected VSG

Abstract

The invention discloses an active oscillation suppression method for a grid-connected VSG. The method comprises the following steps: acquiring grid-connected data information of a grid-connected side in real time; performing reactive droop control to obtain a reactive control output quantity; calculating electromagnetic power output by the VSG and performing active droop control to obtain an active droop control quantity; performing transient feedback power compensation by adopting a lag link and a compensation link to obtain a transient feedback power compensation control quantity; performing virtual inertia control to obtain an active control output quantity; performing voltage and current double-loop control to obtain a PWM control signal; and controlling the grid-connected VSG by adopting a PWM control signal to complete grid-connected VSG control and active oscillation suppression. According to the invention, transient feedback power compensation is carried out by adding a lag link and a compensation link on a control loop, and innovative grid-connected VSG control is combined, so that active oscillation suppression of the grid-connected VSG is realized, the overshoot of grid connection is small, and the grid connection performance is more stable and reliable.

Description

technical field [0001] The invention belongs to the field of power electronics, and in particular relates to a method for suppressing active power oscillation of a grid-connected VSG. Background technique [0002] With the development of economy and technology, virtual synchronous generator (virtual synchronous generator, VSG) technology has been widely used in the field of power system and plays an important role. Therefore, it is particularly important to study the control of virtual generators. [0003] Grid-connected virtual synchronous generator technology is widely used in the field of power systems. The block diagram of the existing grid-connected virtual synchronous generator control system is as follows: figure 1 shown in figure 1 In the power calculation of the grid-connected side output line, the reactive power Q e and active power P e ; Usually the line impedance is inductive, so reactive power and active power can be fully decoupled, reactive power control ...

AI Technical Summary

Problems solved by technology

[0004] However, the existing grid-connected virtual synchronous generator control methods are generally realized by adding fixed damping or transient damping

However, the control method of adding fixed damping will increase the steady-state deviation while suppressing the transient oscillation; while the control method of increasing transient damping will not increase the steady-state deviation, but there is a large overshoot problem. Moreover, the transient active power overshoot under grid frequency disturbance is very large

Therefore, it can be found that the existing control of the grid-connected virtual synchronous generator by adding fixed damping or transient damping cannot take into account both the transient performance and the steady-state performance at the same time, which makes the control of the grid-connected virtual synchronous generator poor control

Images