VSG Robust Adaptive Control And Voltage Harmonic Elimination Under Weak Current Network

Human development and progress can’t depart from the support of energy,energy consumption rate is with the improvement of economic and life faster and faster.In the fossil energy under the pressure of the large amount of consumption and environmental pollution problems and makes people have to give attention to new energy generation provides a way to solve the problem of massive energy consumption and environmental pollution,provides the ways to improve with the continuous development of power system and technical distributed generation will gradually dominate the power,but it brings problems to the power grid.Virtual synchronous generator（VSG）control is to introduce synchronous generator control into the inverter to make the inverter simulate the characteristics of synchronous generator to improve its performance.This thesis is based on VSG control strategy.Firstly,according to the control principle and mathematical model of SG,VSG control is designed and its topology is built.On the analysis of synchronous generator governor and excitation controller design VSG control of active and reactive voltage-frequency.The inverter is modeled and the voltage current double loop control and its related parameters are designed.Secondly,the nonlinear mathematical model of VSG is established.In order to enhance the stability of VSG,the robust adaptive control strategy is used.Considering the uncertain parameters of VSG,the parameter nonlinear mathematical model of VSG with uncertainty is determined,and the robust term and adaptive law with parameter estimation are designed.Therefore,the robust adaptive control is designed,which can well maintain the frequency and voltage amplitude of the system output in case of power fluctuation.Then,in order to solve the problem of high harmonic content in weak current network,a voltage harmonic control strategy is used.Recursive Least Square Estimation（RLSE）is designed to measure the harmonic content of the power grid,and then the voltage harmonic controller is designed.The measured harmonics are input into the designed voltage harmonic controller to reduce the harmonic content of the mesh point.Finally,VSG simulation model is built on MATLAB / Simulink simulation platform.VSG,VSG with feedback linearization control and VSG with robust adaptive control are simulated when the load power changes;The harmonic elimination of VSG under weak current network is simulated,and the simulation results are analyzed.It effectively proves the feasibility of the control strategy proposed in this thesis.