A novel cascaded multilevel converter based DSTATCOM integrated with distribution transformer

摘要

This paper presents a novel cascaded multilevel converter (CMC)-based distribution-type STATCOM integrated with distribution transformer for medium voltage application. The star-connected, n-level CMC is connected to the winding taps on the primary windings of the transformer to achieve voltage stress reduction and maintain a flexible connection voltage level. Taking full use of the spare capacity of distribution transformer, a compromise between cascaded cells count and the voltage stress is achieved. The CMC-based DSTATCOM is controlled as a controlled current source to inject compensation current to the primary windings through the taps. A modified decoupled current control is proposed to control the system. Simulation model and scale-down prototype are developed to verify the performance of the proposed integrated structure. Simulation and experimental results demonstrate the good performance of the proposed structure for reactive power compensation.