An Amorphous Alloy Magnetic-Bus-Based SiC NPC Converter with Inherent Voltage Balancing for Grid-Connected Renewable Energy Systems
This paper presents an amorphous alloy magnetic bus-based neutral point clamped (NPC) converter for grid-connected renewable generation systems. In the proposed system, the amorphous alloy high-frequency high-power density multi-winding magnetic bus generates balanced dc supplies for the five-level 5L-NPC converter for high-quality power conversion. Compared to the traditional NPC converter topologies, the proposed magnetic bus-based architecture does not require any control circuit for voltage balancing of the series connected capacitors. The magnetic bus inherently overcomes galvanic isolation issues and may reduce the size of the boosting inductor. In this paper, a finite control set model predictive control (FCS-MPC) algorithm is derived to control the grid-connected 5L-NPC inverter for multilevel voltage synthesizing, while realizing the user-defined active and reactive power values. To verify the proposed concept, a simulation model is developed and analyzed in MATLAB/Simulink environment. To validate the technology a scale-down prototype test platform is developed in the laboratory with silicon carbide switching devices which realize high blocking voltage, low power dissipation, high switching frequency and high-temperature operation. Based on the simulation and the experimental results, it is expected that the proposed converter will have a great potential for widespread application in renewable generation systems including superconducting generator-based wind turbines.