Direct Multivariable Control for MMC: Digital Signal Processing and Experimental Results

Modular Multilevel Converters (MMC) have opened the road for power electronics to many new and demanding applications in the high power range. The increased degrees of freedom of MMC and the higher number of variables to be controlled have to be fully used by advanced multivariable control (MVC) concepts. Fast and independent control of all essential variables establishes a solid basis for fully electronic fault management, fault ride through and tight control of the internal arm energies of the converter. The new MVC concept - suitable for MMC with high level count - has been implemented based on FPGA-Hardware and digital signal processing of the measured values. Experimental results of the control performance, using a down scaled MMC with 96 submodules (SM), are presented.