Voltage Balancing and Energy Sorting of 17L-ZPUC-Based Modular Multilevel Converter

Z Packed U-Cell (ZPUC) converter is a novel multilevel topology that was proposed for both single-/three-phase applications and Modular Multilevel Converter (MMC) configurations. MMC is a promising topology that gained a lot of interest in the medium-/high-voltage applications due to its various features such as modularity, scalability, and reduced harmonic contents. In MMC, increasing the number of submodule (SM) per arm increases the number of generated voltage levels and results in obtaining better quality waveforms but on the expense of increasing the overall components count. However, with ZPUC-MMC a higher number of voltage levels could be generated with a reduced number of SM and then with a reduced component count. In addition, ZPUC-MMC features a fully integrated voltage balancing (VB) algorithm within the Phase-Shift Pulse Width Modulation technique, thus no additional controller is required. This paper details the integrated VB and energy sorting algorithms of ZPUC-MMC employing two ZPUC-SM in each arm. The performance of the converter along with the VB are validated with MATLAB/SIMULINK. 17 level (17L-) phase voltages are generated while the flying capacitors of each ZPUC-SM are fully balanced and regulated.