Design Of Grid Simulator Based On Double Power Sliding Mode Disturbance Observer

In recent years,with the widespread use of high-power systems,the standards for the integration of wind power systems into the grid have become higher and higher.That is to say,the wind power system is still required to continue to operate in parallel when the grid fails,so it is necessary to study its operation under different faults.But usually the output of the grid is a standard three-phase sinusoidal voltage and various types of grid faults are rare happened.Therefore,in order to test the grid-connected equipment,it is of great value to develop a grid simulator capable of simulating various types of grid faults.The main research focuses of this paper include: 1.Analyze the working principle and functional requirements of the grid simulator and design the rectifier side.2.The control strategy of the inverter side is studied and improved.3.Analyze the dead zone problem existing in the inverter and compensate it.The details are as follows:1.Firstly,the research status of wind power generation and grid simulator technology is analyzed.According to the faults existing in the current grid,the main functional requirements of the grid simulator are established,such as simulate three-phase voltage imbalance and voltage amplitude abrupt change.Besides,the rectification side of the grid simulator is introduced and the design scheme is given.2.Next,the design of the inverter side of the grid simulator is studied.An improved double-power approaching law is firstly proposed to solve the chattering problem existing in traditional sliding mode control.Then the controller is designed based on double power.Finally,the simulation proves that the double power sliding mode controller can effectively eliminate chattering.3.In the control of grid simulator,a dead zone compensation method based on DOB(disturbance observer)is proposed for the dead zone problem in the inverter side.Firstly,the principle is introduced and its function is analyzed.The simulation model is built by Simulink to verify the improvement of the current waveform after the dead zone compensation.4.The simulation model is built under the Simulink and the PHIL real-time simulation technology and FPGA development is introduced.Finally,a 10 kW physical platform is built based on PHIL simulation technology.Finally,the effectiveness of the grid simulator designed in this paper is verified on the physical platform.