Reduced Order Modelling for Solid-State Transformers Based on Active Unity Power Factor Modules

This work is focused on modelling and simulation of input series output parallel (ISOP) multilevel Solid-state Transformers (SST) based on active unity power factor rectifier modules (PWM-UPFR). The computational burden of simulations based on commercial software blocksets drastically increases with high number of modules. This work proposes a method to reduce the simulation complexity by simplifying the rules for switching instant calculations: the branch-zero cross condition is implemented by simple algebraic rules and diode blocks can be removed from the continuous conduction mode of operation. The computational enhancement and accuracy of the proposed modelling is proved by experimental verification using a single-phase single-cell prototype.