This study presents a new multilevel inverter (MLI) with reduced devices, for low/medium-and high-voltage applications. The proposed MLI is evolved from existing cross-connected source-based multilevel inverter (CCS-MLI), results in reduced switches, driver circuits, diodes, and DC voltage sources when compared with the classical CHB, CCS-MLI, and other MLIs. Owing to reduced device numbers, the complexity, size, cost, and maintenance of the proposed topology are greatly reduced. The detailed analysis and working of the proposed topology is presented along with its comparison with classical, CCS-MLI, and other MLIs. Different algorithms are presented for selecting appropriate magnitudes of DC voltage sources to generate different voltage levels in the output. The proposed MLI is suitable for grid integration of renewable energy sources. The concept is presented through modelling and simulation in MATLAB/Simulation environment and validated through real-time simulator OPAL-RT (OP-4500).
Switched capacitors (SCs)-based modules are being increasingly used for multilevel DC to AC power conversion, especially for low input voltage applications. Many of these topologies operate in two stages involving H-bridge switches, which endure high-voltage stress. The SC 9-level module (SC9LM) presented here operates in a single stage with one DC source and two capacitors. In addition, the peak inverse voltage of all power switches is confined to the voltage of the input DC source. The proposed 9-level module ensures a reduced number of power switches. In addition, with appropriate utilisation of states, two of the eleven switches in the module operate at fundamental switching frequency, thereby minimising the switching losses. A single SC9LM achieves a voltage gain of two. The proposed module is validated through circuit analysis followed by simulation and experimental results.
A major disadvantage of two-stage topologies of switched capacitors based multilevel inverters is the use of H-bridge switches which endure high peak-inverse-voltage (PIV). In such topologies, the H-bridge stage is preceded by a levelgeneration stage which synthesises unipolar voltage levels. In this work, a bi-polar module is proposed which can synthesise nine levels at the AC terminals with a single DC input. The proposed module uses power switches with PIV equal to that of the input DC source. Use of switched capacitors in each of the proposed module enables a voltage gain of two. Such bi-polar voltage-doubler modules can be easily connected in a cascaded fashion to increase the number of levels, without involving Hbridge switches. Working modes of the module ensure that the capacitors are self-balanced. A complete analysis of the proposed module is presented. Also, experimental results are presented for validation. In addition, a comparison with other topologies has been presented.
The generation of electricity by dissociating water into H 3 O + and OH − ions through a hydroelectric cell (HEC) without liberating any toxic waste has achieved a groundbreaking feat. Nanoporous magnesium-doped SnO 2 and cobalt-doped SnO 2 materials have been prepared via a novel sol−gel method. The X-ray diffraction patterns of Mg-doped SnO 2 and Co-doped SnO 2 completely match with those of pure SnO 2 , which confirms the interstitial substitution of Mg and Co in the pristine SnO 2 . The results shown by Brunauer−Emmett−Teller theory curves illustrate the surface area of Mg-doped SnO 2 and Co-doped SnO 2 to be 46.22 and 46.81 m 2 /g, respectively, with their pore radii being ∼3 nm. The synthesized nanoparticles were pressed into square pellets of area 4.08 cm 2 . A zinc electrode was pasted on one side of each pellet and silver was painted on the other side to develop the HECs. The fabricated HECs of Mg-doped SnO 2 and Co-doped SnO 2 with 4.08 cm 2 area deliver short-circuit current, open-circuit voltage, and off-load output power of 41.69 mA, 0.787 V, and 32.81 mW and 77.52 mA, 0.454 V, and 35.19 mW, respectively. Cyclic voltammetry of both materials exhibited cathodic and anodic peaks in relation to the redox reactions taking place at Zn and silver electrodes. Nyquist curves of both HECs in the wet state confirm the ionic diffusion of split H 3 O + and OH − ions as compared to the dry state. An off-load output power of 35.19 mW delivered by the HEC of Co-doped SnO 2 with 4.08 cm 2 area is quite promising and has great potential to replace other green energy sources.
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