Highly Efficient, Full ZVS, Hybrid, Multilevel DC/DC Topology for Two-Stage Grid-Connected 1500V PV System with Employed 900V SiC Devices

摘要： Highly ef?cient, hybrid DC/DC topology, consisted of a standard interleaved boost followed by a multilevel RSCC (Resonant Switched Capacitor Converter), that employs 900V SiC (Silicon-Carbide) devices, for use in emerging, two-stage, grid connected 1500V PV (Photo-Voltaic) systems is presented in this paper. Operation principle of this topology, controllability of the output voltage and power distribution among the stages in function of the input voltage is described. Partial processing of the input energy and full ZVS (Zero Voltage Switching) transitions in all the switches, over the wide range of input voltages and output power, make this topology more ef?cient in the comparison with the solutions presented in literature. Simpli?ed model of Coss for prediction of ZVS conditions in high voltage applications is presented. This model appears suf?ciently accurate, yet is also simple enough to be included in the optimization program without increasing the time consumption of calculations. Results of multivariable optimization (pareto front) for the presented topology are provided. Previousely described theoretical analysis is fully experimentally con?rmed by building and measuring a 10kW prototype of 8.26kW/kg of speci?c power and 404.6cm3 of volume occupied only by the power stage components. Euro ef?ciency of 99.48% in nominal input/output voltage conditions is achieved.