Study On Decentralizational Modeling And Control Strategy Of Hybrid Cascaded Power Electronics Transformer

Conventional Power Electronics Transformer use multi-level structure with the voltage,capacity level increases,and the control system is quite complex,and due to the increasing number of cascaded modules,the volume and cost will be doubled.These are the problems restricting the promotion and application of power electronics transformers.Based on these problems,the topology,modeling methods and control strategies of power electronics transformers was studiedFirst,several existing typical power electronic transformer(Power Electronics Transformer,PET)topology and the advantages and disadvantages are analyzed,and the resonant converter and two-level square-wave converter were introduced into the traditional cascaded power electronic transformer,a new power electronic transformer topology is proposed for medium and high voltage distribution network.Compared to the conventional PET,the volume the new topology is significantly reduced,the operational efficiency is improved,and it can operation flexibility switch to pure active and reactive power compensation modeSecond,the new topology and operating principle were discussed in detail,and the establishment of an average model of AC side and the DC side of the system,Third,on basis above,combined with the operating characteristics of the resonant converter presents a single-class unified control strategy PET simplified control system.A PET simulation system 10 kV / 1.5MW Build was built,the simulation results show that the new power electronic transformer topology and control strategy were feasibility and effectiveness.