Research On Simulator Based On Voltage Source Inverter For Permanent Magnet Direct Drive Wind Generator System

As the wind energy has experienced impressive growth on a global scale, ithas become more important and urgent to study and test the wind power generatorsystem in depth. Due to the uncontrollable natural characteristics of wind speed andthe expensive experiment cost, it is very difficult to conduct the experimental studyof full size wind turbine systems in the real wind farm environment. It is necessaryto develop ground-based experimental platform to simulating the wind turbinegenerator system in initial stage of research.By reading and analyzing a large amount of literature in the relevant field athome and abroad, this paper discusses the disadvantages of wind turbine simulatorusing electric motors, and by drawing from other energy sources simulators such asthe power grid and marine turbine, a novel wind turbine generator simulator using athree phase voltage source inverter (VSI) is proposed. The proposed simulatorwhich comprises the numerical models of the entire wind turbine generator systemand the voltage source inverter brings about several advantages commonly requiredin a laboratory such as simple structure, low cost, free-maintenance, portability,and safety.In the proposed simulator, the real wind turbine is replaced with thecorresponding numerical model which has been implemented in DSP with acorresponding typical torque coefficient characteristic CT(λ) described by ahigh-order polynomial curve fitting function, the virtual rotational speed of thewind turbine can be determined in real-time according to the numerical model ofthe mechanical transmission subsystem, and the permanent magnet synchronousgenerator is simulated by the numerical model of PMSG in d-q rotating frame andDSP-controlled voltage source inverter. In order to accurately control the outputvoltage and frequency of the simulator and reproduce the external electricalcharacteristics of the generator accurately, the double closed-loop PI control andvoltage-feedback control algorithms have been employed in this paper.Based on the Simulink modeling by MATLAB, an experimental platform with15kW voltage source inverter and host computer is constructed, by which theproposed algorithms are verified under different static and dynamic conditions. The simulation and experiment results show that the proposed simulator has excellentdynamic performance and high steady-state precision, and can accurately simulatethe external mechanical and electrical characteristics of the actual wind turbinegenerators. And it can be used for the experiments of the wind turbine generatorsystems in the Lab.