This paper develops a simple design of unit cells to be taken in use in series-connected multilevel inverters. The proposed structure not only reduces the part counts efficiently but also increases the number of generated levels in the output voltage. By aggregating the cascaded series-connected units as the basic module, the proposed structure follows one H-bridge circuit. The basic module acts as the initial stage in direct current/alternative current conversion within which all the positive and zero levels are produced. Afterwards, the H-bridge circuit affords the production of symmetric sine-wave by realizing negative levels.To assure the expected operational objectives, we developed three different algorithms to determine the magnitude of input direct current voltage sources. Moreover, to further investigate the proposed structure, different switching algorithms such the fundamental switching frequency and pulse width modulation level shifting approaches are implemented and compared with each other. Extensive numerical and experimental studies are conducted to yield in a suitable evaluation platform. The obtained results demonstrate a superior performance of the proposed structure rather than the conventional topologies.depreciate the satisfactory performance of the proposed structure for low levels output voltages. For these cases, the THD content increases. This point is easily recognized in Figure 22. However, by increasing the number of levels, we obtained a more sinusoidal and clean waveform. Thus, a higher service quality is guaranteed. This in turn increases the count of power electronics devices and Figure 18. Experimental results for the proposed nine-level structure. (a) Basic module voltage (V o1 + V o2 ), (Time/div = 5 ms), and (Voltage/div = 2 V by 1:10 probe). (b) Sinusoidal output voltage waveform. (c) Output current waveform. [Colour figure can be viewed at wileyonlinelibrary.com]
Summary
This paper presents a new structure for a quasi‐resonant switched capacitor multilevel inverter. This structure offers multiple features of the conventional multilevel structures. Moreover, regarding the provided output voltage levels, the proposed structure exploits a new quasi‐resonant basic module which helps to diminish circuit cost and complexity using fewer power components. In the proposed structure, the balancing of capacitors voltages is achieved by series and parallel connection with the voltage source and without the need to employ a complicated control system. In order to obtain higher voltage levels at the inverter ac side, a developed H‐bridge is used in which the basic module is extended horizontally in separate cells on either side. Through a quasi‐resonant inductor deployment in the basic module, current spikes of capacitors are filtered which overwhelms decreasing of capacitor value and also lengthening the capacitor lifetime besides decreasing electromagnetic interference (EMI). Coupled with extensive simulation studies, experimental analyses are conducted to validate the performance of the proposed 17‐level inverter.
This study introduces a boost multilevel inverter (MLI) based on a switched capacitor structure. The proposed inverter features high modularity as a result of which more levels and ratings of voltage can be obtained in the inverter AC terminals. The extension of this topology in both symmetric and asymmetric configurations are introduced and analysed. Taking advantage of the switched‐capacitor technique, only one DC source is utilised while the voltages of several capacitors are kept balanced without the adoption of any sophisticated balancing algorithm. A combination of two basic submodules named as boost switched capacitor submodule and dual switched capacitor submodule forms the proposed structure. Compared to the existing alternatives, the proposed one provides more voltage levels with a lower number of power switches and input DC sources. The performance of the presented MLI is verified through the MATLAB/Simulink environment. Finally, the experimental results are presented, validating the feasibility and effectiveness of the studied inverter.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.