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This study proposes a modular high voltage gain structure for non-isolated non-coupled inductor based multi-input (NINCIBMI) dc-dc converters. Proposed topology can produce higher voltage gains per number of components (switch, diode, capacitor and inductor) than other NINCIBMI topologies. In other words, the proposed topology uses less number of components for achieving the same voltage gain. This property can lead to reduced cost, size, weight and complexity of topology. Also, proposed topology benefits from continuous input current. Despite the high voltage gain of proposed topology, it has considerably low normalised voltage stress (NVS) on its switches/diodes. Another important advantage of proposed topology is that, as the number of input units increase, the voltage gain increases too, but the NVS on switches/diodes decreases. The proposed topology is suggested for low and medium power applications. The 2-input version of proposed topology has been studied in detail and different operational modes and steady-state analyses have been presented. For a better evaluation, proposed topology has been compared with recently presented novel multi-input high step-up structures. The 2-input version has also been experimentally implemented. Obtained results confirm appropriate performance of proposed topology.

This study proposes an improved non-isolated single-inductor multiple-input buck DC–DC converter, with reduced number of components. Less component count can reduce the size, mass and cost of converter. Simultaneous or independent power transfer capability has been provided for input sources. The bidirectional power flow capability has also been provided through usage of a battery without any additional switches. This makes the topology very suitable for hybrid energy systems or hybrid electric vehicle/electric vehicle applications. Different operational modes of proposed topology have been presented. Then, a generalised relationship has been proposed for calculation of critical inductance (as an important design parameter) of proposed n-input buck topology. To make a better judgement, the proposed topology has been compared with recently presented novel topologies. Also, a simple proportional–integral based controller has been applied to regulate output voltage and assign the portion of power that each input source should provide. To confirm the validity of proposed topology and theoretical concepts, the three-input version has been modelled and simulated in PSCAD/EMTDC software and implemented experimentally. Simulation and experimental results validate proper performance of proposed topology.

This study investigates a multiple input buck dc–dc converter. Different operational modes of the converter for two-, three- and four-input sources are studied then, for each item the relation of critical inductance between continuous conduction mode and discontinuous conduction mode is calculated. Finally, a generalised relationship is proposed for calculation of critical inductance of n-input topology, which is true for any number of input sources. Experimental and simulation results in power systems computer-aided design/EMTDC are presented to validate the theoretical concepts and proposed generalised relation of converter critical inductance.

A 15-level flying capacitor multi-cell based inverter with new control method is proposed. The main benefit of this topology is minimising the number of components (switches, insulated-gate bipolar transistor (IGBTs), diodes, flying capacitors and DC sources with minimum variety number) that are used for producing the same number of output voltage levels. The proposed novel control strategy is capable of regulating voltage of flying capacitors on desired values, which results in increased number of output voltage levels. Another feature of the proposed control strategy is robustness against the load changes. Moreover, a new algorithm is presented for determining the voltage rating of flying capacitors. Simulations carried out in PSCAD/EMTDC software package and the experimental data were validated against numerical results.