Development of a more flexible low-level control for MMC applications

With the increasing amount of MMC (Modular Multilevel Converter) applications, the need for low-level control algorithms is also increasing. Most low-level algorithms still belong to the FPGA platform. Therefore, unless one is experienced in developing and implementing on a particular FPGA platform, addressing the need for a low-level control algorithm can be extremely difficult. In addition, the cost associated with the development environment and a testing FPGA hardware platform makes it even more difficult to develop such algorithm. This paper introduces a more flexible method of low-level controller development by using a real-time digital simulator (RTDS) as a platform. This allows the developed low-level control model to be interfaced with an FPGA based MMC simulation in the same real-time digital simulator. The flexibility and usefulness in the proposed method is shown in a comparison of the sorting algorithms in NLC(Nearest Level Control) type low-level MMC control.