Real-Time Implementation of a 31-Level Asymmetrical Cascaded Multilevel Inverter for Dynamic Loads

Abstract

Among the renewable energy applications, the most popular inverters are cascaded multilevel inverters. Irrespective of numerous benefits these inverters face reliability issues due to the presence of more circuit components in the design. This has been a critical challenge for researchers in designing inverters with enhanced reliability by reducing the total harmonic distortion (THD). This paper proposes a 31-level asymmetric cascaded multilevel inverter for renewable energy applications. The proposed topology produces waveforms consisting of the staircase with a high number of output levels with lesser components with low THD. The investigations on the feasibility and performance of MLI under steady-state, transient, and dynamic load disturbances. The results are validated from a 1.6kW system which provides the proposed inverter.INDEX TERMS Multilevel inverter (MLI), total harmonic distraction (THD), staircase modulation technique.

Analytical Formulation and Minimization of Voltage THD in Staircase Modulated Multilevel Inverters With Variable DC Ratios

“…29The second and simpler OMTHD "configuration B" (cf. Section 3.A), is defined in (29), where the set of DCRs are treated as constraints instead of design variables. This configuration can be used to obtain optimum SAs when the DC source voltage values are enforced, as well as for the EDCS case, using (6).…”

“…This configuration can be used to obtain optimum SAs when the DC source voltage values are enforced, as well as for the EDCS case, using (6). The proposed OMTHD problem described by (28) or (29), can be solved using any Directsearch based global optimization algorithm, such as MATLAB's "Global Pattern Search" (GPS) [31], which was the algorithm of choice in this work, since the GPS algorithm is less sensitive than the highly stochastic Genetic Algorithm (GA), commonly employed for OMTHD [14], [17]. The novel OMTHD problem is intended for offline calculation of optimum SA and (optionally) optimum DCRs.…”

“…Recalling from Section 3.A that MTHD is simply OMTHD with the ME restrictions lifted, so the optimum SAs and (optionally) DCRs are calculated based solely on absolute minimum THD. Both problem configurations "A" (28) and "B" (29), can be used to obtain MTHD optimal variables by lifting the ME and MDCR conditions, setting and MDCR to a very large value ( −1 in MATLAB). Tables 4 and 5 for the PTHD case and in Tables 6 and 7 for the LTHD case, respectively.…”

“…The proposed generic OMTHD configurations from (28) and (29) were programmed as MATLAB scripts, employing the GPS algorithm [31]. Optimum sets of SAs and optionally DCRs for 13 different values of N were obtained for EDCS and UDCS (phase and line voltages), using 101 evaluated MI points per each N value.…”

Design and implementation of a novel asymmetrical multilevel inverter optimal hardware components

“…Also, finding their appropriate use in renewable energy systems, which include smart and micro‐grids. There is always a scope of improvement of efficiency and reduction in the harmonic distortion has always become a concern for the researchers …”