Research On The Flyback Ac/ac Mode Three-level Ac/ac Converter

The Circuit topology of the Flyback AC/AC mode three-level AC/AC converter proposed in this paper has applied for patents for inventions in China(Number of Applications: 200910232474.8).Firstly, this dissertation presents technique of AC/AC converter, technique of multi-level and its application in the fields of ac/ac converter. Secondly, basing on the principle of three-level switch cell and the purpose of multi-level application, two topologies of Flyback AC/AC converter are proposed, which are Single-ended Flyback three-level AC/AC converter and Double-ended Flyback three-level AC/AC converter. Compared with the Double-ended Flyback three-level AC/AC converter, the Single-ended Flyback three-level AC/AC converter is simpler. In this paper, we choose Single-ended Flyback three-level topology to have a research on its steady principles.The transient voltage feedback control strategy is analyzed in details, the operation modes and steady principles of proposed converter are investigated in this paper., the external characteristics of this converter is given. The stress of power switches of proposed converter are also analysed. Compared with the Flyback AC/AC mode two-level AC/AC converter, the voltage stress of the power switch could be lowered by Flyback AC/AC mode three-level AC/AC converter,so it can be used to higher ac voltages.Finally, the result of the Simulink simulation and principle test of the 500VA220V±15% 50HzAC/110V50HzAC Flyback AC/AC mode three-level AC/AC converter is given. Experimental results are identical with theory analysis, so the correction and advance of this converter is further verified.