Abstract
Z packed U-cell (ZPUC) converter topology is presented in this paper as a new type of multilevel converter topology that can be operated in a single phase as well as in three-phase configurations while using a single DC source. Since each U-cell includes two switches and one capacitor, in this topology, three U-cells are needed to generate 5 or 7 voltage levels. Moreover, the configuration proposed for the ZPUC is more appropriate for high-power application modular multilevel converters (MMCs) to increase the voltage levels compared to other topologies. Accurate voltage balancing on small-sized auxiliary capacitors is due to integrated modulation strategy without using additional controllers; additionally, the reduction of total harmonic distortion (THD) in AC currents for higher voltage levels is an advantage of this configuration. A full topology sequence of operation and performance analysis of ZPUC based on the 5-L inverter is investigated in Matlab-Simulink and experimentally validated on a 3 kVA prototype. The obtained results illustrate the good dynamic performance of the proposed topology and the implemented integrated switching pattern voltage balancing.
Highlights
Multilevel converter topologies have become more popular and are progressively replacing two-level converters due to their high impacted advantages on reducing the size of harmonic filters, increased nominal power capability and component voltage stress reduction [1]
Ip is the peak of the load current, C is the capacitance of flying Capacitor (FC) in Z packed U-cell (ZPUC) converter, v is the peak to peak voltage ripple which can be selected based on permissible value in associated applications
SIMULATION RESULTS The proposed converter has been studied by simulation using MATLAB/Simulink on standalone feeding RL loads and grid connected system in order to verify the proposed topology operation as well as the proposed control method on ZPUCMMC
Summary
Multilevel converter topologies have become more popular and are progressively replacing two-level converters due to their high impacted advantages on reducing the size of harmonic filters, increased nominal power capability and component voltage stress reduction [1]. Cascaded full bridge, flying Capacitor (FC), neutral point clamped (NPC) and active neutral point clamped (ANPC) are the popular and classic topologies of multilevel converters that have been commercialized in recent years, replacing conventional converters in several industrial applications [2]–[5]. Multilevel converters present many challenges related to isolated DC sources [8], topology complexity [9], modulation techniques [10], modeling and control [11], as well as the voltage balancing challenge [12] of flying capacitors that have persuaded researchers and industries to improve and enhance their performance. Reducing the power losses in semiconductor switches and the sizes of filters are the other useful features of MMCs [15], [16]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
