Research On Quasi-Z-source Topology For DC-DC Converter

Along with the rapid development of high technology,power technology has madeachievements both in the aspect of theory and product application recently.Powerequipment is not only the foundation of normal electronic equipment,but it plays animportant role in the transformation of the electrical energy and power relay.Powersupply towards to the trend of more efficient,lower cost and lower noise.The single topology structure of switching power supply have a theory defect.If itrequires a higher or lower output voltage,an additional DC-DC converter is needed.Itexists dead zone which will low the system efficiency. This paper presents aQuasi-Z-source converter that is used in DC voltage transformation,which is a newtopology derived from the traditional Z-source.The qZSI inherits lots of advantages ofthe ZSI, which can realize buck/boost conversion and power conditioning in a singlestage with improved reliability.It has the unique advantage of lower component ratingand constant DC voltage from the source and simplify control strategy.It is suited forapplications which requires a large range of gain for motor controllers or renewableenergy.The operating principle and topology structure of Quasi-Z-source converter hasbeen presented in this paper,giving design method and design principles of maincircuit,etc:parameter selection of capacitance,inductance,diode of Z-source.Small signalmodel mathematical models of the Z-Source converter are established through the StateSpace averaging method.The non-linearity and time varying equations are putted intothe linearity equations.The transfer functions are gotted and analyzed.At last,under Saber environment,the simulation model for a quasi-Z-source isestablished.The simulation and experiments are made on it.It turns out thatQuasi-Z-source converter’s output voltage regulation characteristics,output ripples,dynamic responses meeting requirements of the project.All the technical indicators aregood to meet the requirements of the Quasi-Z-source converter.The simulations andexperiments are made on the Quasi-Z-source converter.The analysis shows thecorrectness of the theory analysis and feasibility of the proposed methods.