Study On Control Strategy Of PMSG Wind Power Generation System Based On Z-Source Inverter

Along with environmental pollution and energy shortage,developing clean new energy becomes the hot of the present study.The wind power as the longest of the fastest growing clean energy,attracts more and more researcher's attention from home and abroad.In the field of wind power,wind power generation system undertakes the important role of energy conversion,and the inverter as the core component in the system.It plays an important role of energy transfer and energy conversion,directly affect the quality of the wind power system interconnection.Due to the limitations exist in traditional voltage type inverter,in recent years,scholars have put forward the Z source inverter,and a new Z source inverter can overcomes these disadvantages and have better grid features.This article will put Z source inverter into permanent magnet direct-drive wind power generation system,and the research of the Z source inverter control strategy will improve the quality of the grid.First of all,this article through the analysis of the mathematical modeling of wind turbine is derived,which provides theory foundation for the maximum power point tracking mathematics.Through to the Z source inverter state of direct and not through mathematical analysis,the capacitor voltage,busbar voltage,through the mathematical relationship between duty ratio and other variables.Then through the method of switching function and duty ratio method for three-phase Z source inverter for mathematical modeling,and under the three-phase static coordinate system and two-phase rotating coordinate system of three-phase Z source inverter mathematical model is established,and the traditional mathematical model of the inverter has a similar place,deduce the traditional voltage type inverter current control strategy can be applied to the Z source inverter control,and it provides the theoretical basis for research.Second,when the wind turbine affected by wind speed change,wind power system power and current vulnerable to outside influence,in order to improve the stability of the system,by analyzing the basic principle of Z source,is proposed in this paper,based on the Z source wind power dead beat current inner loop control strategy.Established by stable Z capacitance voltage source network,adjusting the pass-through adjustable speed control duty ratios of maximum power point tracking(MPPT)control strategy,and the virtual flux observer orientation combined with dead beat control strategy,through the virtual flux observer orientation,coordinate transformation method to solve PLL phase-locked loop trival,poor stability of vulnerable to outside influence.Based on the Z source inverter SVPWM modulation strategies,and the comparative analysis with traditional SVPWM are simulated.At the end of the paper,using the Matlab/Simulink to build the system of wind turbine model firstly,and the analysis of the waveform is verified the correctness of the proposed MPPT control strategy.Then based on dead beat control of permanent magnet direct-drive wind power system are simulated,and the simulation waveform is analyzed.The simulation results confirm the validity of the control strategy,and the sinusoidal of side grid current waveform is good.lt has good dynamic response and stable operation,and the system can achieve unity power factor operation,etc.