Based On The The Spwm New Asymmetric Multi-level Inverter

In recent years, multilevel power conversion technology has been becoming hot point in power electronic research due to extensive outlook in high power application. Novel topologies and modulation strategies concerning multilevel converters are emerging continuously. As far as the width and depth are concerned, research on multilevel technique is advanced greatly.In the dissertation, "Multilevel Building Blocks", which is suitable for the construction of the new inverter topologies, are analyzed based on the concept of "Power Electronics Building Blocks". Then, a new kind of asymmetric multilevel topologies was introduced based on this new concept. According to their features, a SPWM control schema especially for these topologies was put forward in the thesis. After software simulation and hardware experimentation for one typical topology among them, we came to the conclusion that these topologies can work efficiently once properly controlled and the SPWM schema especially for these topologies can effectively control these circuits. Comparing with several traditional multilevel topologies which produce the same output voltage levels, the circuits of new topologies is simpler and the system efficiency is higher.In detail, the principle and features of several existing multilevel topologies are analyzed. A new kind of asymmetric multilevel topologies was proposed and the three-phase topologies are introduced too.The general control methods of multilevel inverters are also analyzed in the paper. And a SPWM control schema especially for asymmetric multilevel inverts is introduced after analyzing the principle of the common carrier PWM schema.The single and three phase systems of the inverter employing the typical asymmetric six-level inerter topology as its main circuit were developed. In detail, the systems are composed of main circuit, control circuit, buffer circuit, drive circuit, and so on. The simulation of three phase as well as single phase of the novel asymmetric six-level inverter topology has been done with MATLAB and the results are satisfactory. In the end, the experiment results are presented, which means the feasibility of the novel topology and the validity of the control schema.