Fpga-based Real-time Simulation of Multilevel Modular Converter Hvdc Systems

AC-HVDC-AC energy conversion systems using modular multilevel voltage-source converters (MMC) are becoming very popular to integrate distributed energy systems to the main grid. MMC AC-DC-AC converters are also being considered for large HVDC transmissions systems. Such multi-level converters pose a serious problem for HIL simulators required for control, protection design and testing due to the large number of cells that must be simulated individually using very small time steps. Such a system also requires managing a very large number of I/O channels within a few microseconds. This paper demonstrates the advantages of using a very small time step to simulate a modular multilevel converter (MMC). To do so, a hybrid simulation is done using Intel PC and FPGA. The MMC is implemented on FPGA to simulate fast transient with a time step of 500 ns to 1 μs. The AC network and HVDC bus is simulated on the PC, with a slower time step of 10 μs to 20 μs. The simulator architecture and the components simulated on the FPGA and on the PC will be discussed, as well as the method allowing the interconnection of this slow and fast system