A DC Voltage Balancing Strategy Based on Active Vector Correction for Single-Phase Cascaded SST

摘要

The disadvantages in power system with traditional industrial frequency transformer can be resolved by Solid State Transformer (SST). Cascaded SST can be transformerless connected to the high voltage grid. However, the output performance and reliability of cascaded SST are seriously influenced by DC voltage balancing problem which exists in cascaded configuration. In this paper, a DC voltage balancing strategy based on active vector correction is proposed. This strategy is characterized by on-demand active power and equal reactive power among modulars. Then, a quantitative analysis method is presented to validate active power adjusting ability of the traditional and the proposed strategies. Simulation and experimental results verify the feasibility and validity of these analysis and strategy.