Design Of Active Disturbance Rejection Controller For Grid Connected Inverter In Energy-fed DC Electronic Load

Energy fed DC electronic load plays a very important role in the pre factory test of DC power supply unit.It can not only simulate the complex load curve that cannot be realized by the traditional load,but also feed back the electric energy output by the power supply to be tested to the public power grid,so as to lessen the energy consumption during testing.Due to the above characteristics and advantages,increasingly stringent power test specifications,energy fed DC electronic loads have become more and more popular.As a converter connecting the load simulate unit to the power grid,the grid connected inverter improves its working performance.It can not only improve the energy feedback efficiency of the energy feedback DC electronic load,but also lessen the contaminated of the harmonic current of the feed power grid to the power grid effectively.Therefore,the research on energy DC electronic load grid connected inverter has practical engineering value and significance.This dissertation takes phase A of T-type grid connected inverter as an template to analyze its working principle.The control characteristics of power grid current under different mathematical models are analyzed in detail.Aiming at the resonance of LCL filter,the timevarying disturbance of public power grid and the coupling of power grid current in dq frame,MC-LADRC is designed in the two-phase static frame system with grid side current as the control variable.Using MC-LADRC equivalent transfer function,the dynamic characteristics,stability and immunity of the system are analyzed.The model is built in MATLAB,and the MC-LADRC is analyzed.In order to verify the correctness of MC-LADRC,it is utilized to a 10 k W grid connected inverter with energy fed DC electronic load for experimental verification.The experimental results show that MC-LADRC can achieve good control of grid connected current.The inverter operates at a power factor of no less than 0.99,and the THD of each grid connected current is controlled at about 2.8%,meeting the national standard for inverter access to public power grid.In addition,the "bandwidth" method is used to tune the parameters of the controller,which has explicit physical purport and high utilization value.