Novel single-phase five-level inverter utilizing digital counter control scheme
Cajethan M. Nwosu – Anthony I. Umeogamba – Cosmas U. Ogbuka
A novel single-phase digital control circuit-based five level inverter (FLI) is presented in this paper. Based on the determined switching angle, one switching cycle of the inverter is divided into segments from which the switching sequence of the inverter switches is digitized. A programmed counter built around J-K flip flops with logic gates provided the needed switching signals for the H-bridge inverter. Proposed inverter is verified through simulation in a MATLAB/SIMULINK environment and simulation results are given. Simulation results show notable reduction in total harmonic distortion (THD) in the inverter output voltage and load current. With an RL load (of 200 W and 0.250 H), a single digit THD of 8.5, 1 % for the inverter load current is realized. Comparison of the novel control circuit-dependent FLI with the conventional and contemporary power-circuit-dependent cascaded H-bridge inverter (CHBI) show that the novel FLI is synthesized with lesser number of power circuit and control circuit components.
Keywords: multi level inverter, switching angle, flip flop, sequential logic circuits, total harmonic distortion