Research On Series Type Of Switched Inductor-Z-source Inverter

In recent years,with the increasing shortage of the main energy resources,such as oil,coal and natural gas,people pay more and more attention on environmental protectitenon,therefore,new energy development and utilization is becoming more and more popular among cencerns of people.Because the direct output of new energy power generation is unsteady DC power,the inverter plays an increasingly important role in the new energy conversion.Now,most of the inverters on the market are buck inverters.In order to prevent the simultaneous conduction of the power switch tube of the inverter bridge with the same bridge arm,there is a need to add dead zone time,however,this will heavily decrease the quality of output waveform.As a result,the Z source inverter comes into being.It has great advantages in the process of electric energy conversion,but there are still some problems which seriously restrict its application and development.In order to overcome the defects of Z source inverters,the thesis conducts in-depth researches mainly from two aspects:the topology structure and control strategy of Z source inverter.Firstly,we have studied the existing three kinds of topology structures and working principles of Z source and make a comparison among their working characteristics.Secondly,a kind of topology of series type of switched inductor-Z-source inverter is proposed for synthesizing the advantages of the three Z source inverters.Besides,its circuit structures and working principles are analyzed and made a comparison with the three previous topology of Z source inverter.Finally,the control strategy and the DSP implementation method based on SPWM and SVPWM are studied,and the influence of different shoot through injection methods on the switching times and loss of the inverter bridge power device is analyzed.This thesis gives a method to the implementation of the program and the main circuit,filter circuit,control circuit,drive circuit,sampling and protection circuit and the design scheme of auxiliary power supply,and it also complete the design work of hardware and software of the system.Finally,a simulation model and an experimental platform are built to simulate and verify the working characteristics of the system.The results show that the proposed series type of switched inductor-Z-source inverter has the advantages of high voltage capacity,low capacitance voltage stress,soft start and so on.