Research On The Application Of Active Disturbance Rejection Control Technology In STATCOM

In recent years, the process of power electronic technology and control theories has promoted the development of electric power system. The use of high power nonlinear devices takes power quality problems to the power system, such as no power unbalance, harmonic and voltage sag etc. Because of the excellent compensation effect and fast dynamic response, the static synchronous compensator (STATCOM) has become an outstanding representative of the reactive power compensation devices.This paper introduces the background of STATCOM, analyzes several common topologies of multilevel inverter in STATCOM, and introduces the characteristics of each kind. This paper compares the common PWM control methods and selects the carrier phase shifted PWM method to control the STATCOM. Then introduce the reactive power compensation principle of the cascaded STATCOM, establishes the model of STATCOM in two kinds of coordinate system (a-b-c three-phase static coordinate system and d-q synchronous rotating coordinate system).The ip-iq algorithm is used in the instantaneous reactive detection technology to detect the reactive current. The paper studies the method of voltage control on DC side and decoupling control on AC side of STATCOM.The paper uses the technology of Active disturbance rejection control based on extended state observer to control STATCOM. Active disturbance rejection control technique is a kind of nonlinear robust control technology, and has great effect on nonlinear control objects. It is mainly composed of three parts, such as tracking differentiator, extended state observer, and nonlinear state error feedback control law. In this paper, an ADRC controller is designed on the basis of STATCOM model. The method of changing the system parameters and load properties is used to get the simulation waveform. The waveform shows that STATCOM has the advantages of fast response, low waveform distortion rate and no overshoot under the control of ADRC, and ultimately proved the feasibility of active disturbances rejection control technique application in STATCOM.