Simulation and Control Strategy of a 5.6~kV 17-level STATCOM Under SVG Condition

Abstract

To achieve high-voltage reactive power compensation, a 5.6kV 17-level STATCOM under SVG Condition is presented. In this paper, we use a cascaded H-bridge multilevel star-connection converter whose system structure and circuit schematic are described. Then by using the phase-shifted carrier modulation strategy and the active-reactive current decoupling method, the STATCOM performs quite well. Moreover modulation strategy of the 17-level STATCOM based on the active disturbance rejection control (ADRC) is presented and the analytical formulas are described. For implementation, control strategy for DC bus voltage balance in cascaded H-bridge multilevel converters, time average distribution method and extreme value offset method are applied in our design. Finally, simulation results demonstrate that the proposed 17-level STATCOM is capable of reactive power compensation, simultaneous controlling and balancing the DC side voltages during the work and verify that high-voltage reactive power can be accurately and effectively compensated.