Design and control of Series DC Active Filter (SDAF) for shipboard Medium-Voltage DC power system

Shipboard power system (SPS) can have either ac or dc distribution systems, or a combination of both ac and dc distribution systems. However, the Navy has identified Medium-Voltage DC (MVDC) as a long-term solution for electric power distribution to meet the high power density requirements in future shipboard power systems. Thyristor bridges are a viable front-end converter topology due to its mature technology, high efficiency, and high current capacity. In such medium-voltage dc systems providing a highly stabilized low-ripple dc-bus is crucial for the reliable operation of entire system. In this paper, a 7.5kV Medium-Voltage DC (MVDC) system based on a twelve-pulse thyristor-bridge configuration is proposed. The system incorporates a Series DC Active Filter (SDAF) to smooth out DC link ripples and improves overall system damping. Detailed design, system components and control, and simulation results for the series DC active filter system are presented in the paper.