Design Of Linear Active Disturbance Rejection Controller For Active Power Filter

The problem of harmonic and reactive power is more serious in electric drilling rig power grids.Active Power Filter(APF)has the performance of dynamic harmonic control and reactive power compensation.Combined with its characteristics of small capacity and low voltage,APF can provide effective solutions for the harmonic and reactive power problems in electric drilling rig power grid.In view of the poor performance of filtering,current tracking and DC side voltage stabilization for APF in the electric drilling power grid using traditional control strategies,this paper takes three-phase four-wire APF as research object,uses Linear Active Disturbance Rejection Control(LADRC)in APF current tracking control and DC side voltage stabilization control,designs a first-order LADRC controller for current loop and voltage loop,and performs simulation research on the performance of APF under this control strategy.It is verified that the designed controller has good compensation performance under the power grid operating conditions of the electric drilling rig.According to the APF structure of the electric drilling rig power grid,the mathematical model of the three-phase four-wire APF in the three-phase static coordinate system is established,and the mathematical model in the synchronous rotating coordinate system is obtained through coordinate transformation.According to the three-phase four-wire power supply mode of the electric drilling rig power grid,the dq0 detection method based on the theory of instantaneous reactive power is selected.The APF double closed-loop control system is established.Based on the APF mathematical model in the synchronous rotating coordinate system,the first-order LADRC of the APF current inner loop is designed,and the parameter setting method is given.Then the stability of the closed-loop LADRC controller is analyzed.The APF power exchange model is established to illustrate the law of energy exchange between the DC side and the AC side,and the first-order LADRC of the APF voltage outer loop is designed and the parameters are adjusted.Matlab/Simulink is used to establish the simulation model of the three-phase four-wire APF of the electric drilling rig power grid,which is controlled by PI and LADRC respectively.It is verified that the dq0 detection method based on the instantaneous reactive power theory can accurately detect the harmonic components of the load current in real time.Then,PI control and LADRC control are used in the current tracking link respectively,and simulation comparison analysis is carried out to verify that LADRC is superior to PI control in filtering performance,current tracking real-time performance and anti-disturbance performance;And PI control and LADRC are used in the DC side voltage stabilization link.The comparative analysis is carried out to verify that LADRC is superior to PI control in both dynamic response speed and antiinterference performance.The final results show that,compared with the APF using the traditional control strategy,the three-phase four-wire APF designed in this paper with the double loop and the first-order LADRC controller can effectively improve the compensation performance,current tracking real-time performance and anti-interference in the electric drilling rig power grid performance.