Research On Grid-connected Photovoltaic System Based On ADRC

Grid-connected photovoltaic (PV) generation system affected by external factors easilyand has a poor anti-interference ability. Environmental changes, power fluctuations,uncertainties of model parameters and other factors will affect the quality of output power andthe operation efficiency of system. Based on these characteristics of PV system, this paperapplies auto-disturbance-rejection-control (ADRC) with a strong anti-interference ability tothe inside and outside disturbance of system to do some relevant research and analysis. Maintasks are as follows:Firstly, this paper makes the analysis about each part’s algorithm of ADRC in details andconstructs the liner auto-disturbance-rejection-control (LADRC) with the characteristics ofless parameter to be tuned. On this basis, this paper adopts double closed loop control strategyand carries out the simulation of grid-connected control on PV system. Here, the outer loop(voltage loop) applies LADRC to maintain the stability of voltage in DC side. The inner loop(current loop) applies instantaneous current control to implement the grid inverter process.Finally, through comparing with PI control under the same conditions, the result tells us thecontrol technology of ADRC can give a better effect and reflect a control advantage andprospects in the PV system.Secondly, we know, grid-connected photovoltaic power system is a typical nonlinearsystem, is vulnerable to outside obstruction and exist many uncertain interference. Regardingthe characteristics of ADRC which does not depend on an accurate system model and is ableto guarantee control accuracy on the role of the unknown strongly nonlinear and uncertaintystrongly interference, through setting disturbance factitiously(change the light condition ofexternal environment), this paper makes anti-interference simulation test and gives thetheoretical analysis. Finally, the technology is further proposed to apply to the photovoltaicpower conditioner system (PVPC) combined reactive power compensation and harmoniccontrol, and the theoretical analysis is also given in details. These works broaden theapplication of ADRC in the PV generation system.