Performance Study Of A New Multi-level Inverter And Modulation Method Based On High-efficiency

There are some advantages in the two-stage inverter whose former consists of a boost convent.for example,the two-stage inverter can work in a wide range of DC side voltages so that the latter is more efficient,less costly and easy to control.But the former consisting of a boost has a lot of power loss and cost which will offset these advantages,so that the value of the two-stage inverter is small.In order to reduce the power loss of the two-stage inverter and improve the practical value,the study put forward three strategies:(1)Change the topology.a novel two-stage multilevel inverter is proposed in this paper.the former uses two-buck converters to provide four outputs for the latter,the special structure allowes a portion of the power to supplied directly from the power supply to the latter stage without passing through the former buck converter.the work can save a lot of current.That the twobuck Topology can reduce more 86% loss than boost topology was verified by the contrast of the former loss with the simulations by Matlab/Simulink.The latter uses Asymmetry Three-level,the structure can take advantage of the characteristics of the former to reduce the latter loss.(2)Change the modulation method.A new relying on the middle-level PWM method is proposed for the new topology taking advantage of the characteristics of the former to reduce the latter loss.we analyzed the former part,the latter switching loss and magnetic loss of the inverter and identified strengths and weaknesses of different PWM methods.The results proved that the relying on the middle-level PWM method can cut former power loss and latter magnetic loss and it was the ideal PWM method of the inverter.(3)soft switching.The paper presents a strategy for DC/DC converters such as Buck,Boost to realize soft switching.The condition of soft switching and the design considerations are analyzed in detail.An experiment has been done to prove the feasibility and validity of the topology.The strategy can apply to other converters and two-stage inverters to realize zero current switching.