Research On Cascade Dual Cuk Multilevel Inverter

Cascade multilevel inverter, in addition to general advantages of multilevel inverter,also has the structure is easy to modular and extended, without balancing capacitor voltage,easy to realize soft switching technology and a series of unique characteristics, hasattracted more and more attention. However, the existing cascade multilevel invertertopologies almost can only buck the input voltage and can’t meet the special demand inthe solar energy, wind energy and other large power new energy generation applications,for the reason of the input DC voltage fluctuate a lot. In order to meet the special needs,the paper proposes a novel single-stage Buck-Boost cascade multilevel inverter topology.Through analyse the basic topology construction principle of cascade multilevel, andcombine with the characteristics of Cuk converter proposes a novel topology ofBuck-Boost type cascade multilevel inverter. The proposed novel Buck-Boost typecascade multilevel inverter is composed of output series dual Cuk inverter which only hasfour active devices,topology structure is simple, the control is flexible, with a certainability to resist input power fluctuation and has the characteristics of boosting or buckingthe input voltage. Analyse the work principle of output series dual Cuk inverter andthe cascade dual Cuk multilevel inverter, on the basis of the analysis of the Cuk converterworking process calculate the main circuit parameter. Through the modeling of the Cukconverter design the controller parameters, adopte the linear voltage single loop controland nonlinear one cycle control to realize the closed loop of the inverter, and analyse theproblem of the excessive starting current in the application of one cycle control. Using thesimulation software PSIM9.0, the above conclusions are validated withsimulation analysis.Based on the theory analysis and simulation research, design and build a2kW of twodual Cuk unit cascade five level inverter prototype, the experimental results are consistentwith the theoretical analysis and simulation results to verify and feasibility of thetopology.