Research On An Improved High Gain Switched Inductor Z-Source Inverter

Z-Source Inverters can complete the single stage rise-down function by balanced the through duty cycle D and modulation ratio M,of the inverter without the addition of other auxiliary circuits because of its unique impedance network.Thus,it has been widely concerned and studied.During the control process of Z-Source Inverter,the reliability of the system is greatly improved because there is no need to worry about the direct-through hazard of the inverter,which makes it appear in various applications.The study of Z-Source Inverter topology extension direction and the characteristics of Z-Source network under different modulation is of great significance to the study of high gain Z-Source Inverter.The research on Z-Source topology focuses on improving the boosting capacity of Z-source network,and has been few studies on the imperfection of Z-source input current.Switching inductance unit has important reference significance for reducing the Z-source volume,improving the boosting capacity of the Z-source network,and increasing the system power density.Based on the analysis of the topology of the traditional switching inductance Z-source,an improved kind of Z-source is proposed.The topology,after keeping the input current of the Z-source continuously,greatly improves the boost ratio of the Z source network,thus reducing the loss caused by the inverter pass-through.the study of many Z-Source modulation methods,although simple boost modulation is simple and easy to implement,it can no longer meet the requirements of high performance control.therefore,the Z-Source modulation ZSVMx(x =6,4,2,1)based on space vector modulation is valued.Through the analysis and comparison of the ZSVMx modulation principle and the detailed study of the inductor current ripple under ZSVM2 modulation,an improved ZSVM2 modulation method is proposed,which introduces two adjustment coefficients.Thus the direct vector distribution is carried out dynamically.Compared with the traditional method,the proposed method can greatly enhance the ripple suppression ability of inductance current.By establishing the mathematical model of the proposed topology,the boost factor of the Z-Source network and the expressions of the capacitance voltage are derived,and the basis for the selection of the main parameters in the system is given.A simulation model is built in Matlab/Simulink environment and a corresponding experimental platform is built to verify the feasibility and effectiveness of the improved method.