Sensorless Control and Synchronization for Solid-State Transformers Based on Active Unity Power Factor Modules

Inhalt:
This work addresses the control of Input Series Output Parallel (ISOP) Solid State Transformers (SST) based on Pulse-Width Modulation Active Unity Power Factor Rectifier (PWM-UPFR) Modules. The synchronization of the AC current references is crucial to achieve distortion-less zero crosses. This work proposes a method to achieve optimal operation by settling a synchronization path that feeds the phase-locked loop with the PWM voltage reference (i.e., with the control action of the current loop). Conditions for avoiding positive-feedback by tuning are discussed, as well as harmonic distortion mitigation by resonant filters with anti-windup. The key performances are proved by experimental verification.