High voltage gain DC-DC converters are widely used in various applications like low voltage sustainable sources. In traditional boost converters, the voltage gain is limited by high voltage stress, high current ripple, and low efficiency due to employing a high duty cycle ratio. In this paper, we propose converters that are a combination of four sub-structures, namely active switched inductor, passive switched inductor, switched capacitor cell, as well as an auxiliary switch with non-isolated configuration. The proposed structures have high voltage gain compared to the conventional either switched inductor-based or switched capacitor-based ones in addition to a low duty cycle ratio. By adding an auxiliary switch, the efficiency is improved, particularly for high voltage gains. The principle of operation and steady-state analysis are discussed in detail. Also, simulation results from PSCAD/EMTDC software are validated by a prototype built for experimental examination. The results are demonstrated that the voltage gain and efficiency could be improved by utilizing the auxiliary switch.

Inverters, as one of the key components of electrical systems, have experienced a great evolution in the last decade, and their performance improvement is a challenge even today, leading to many researches on topologies and control schemes. This study introduces a new multilevel converter topology which is able to supply bidirectional current loads. The proposed structure has fewer power electronic devices such as power switches, driver circuits, power diodes, and DC voltage sources and, can be designed in both symmetric and asymmetric structures. In order to increase the number of output levels and the proposed basic unit development, modular expansion or cascading methods can be used. This study demonstrates that the aforementioned methods have the best results in asymmetric and symmetric structures of the proposed topology, respectively. The comparison between the proposed converter and some previous topologies shows that it has better conditions with respect to the used semiconductor count, switching and conduction losses, and total blocking voltage. The operation and performance of the proposed multi‐level converter have been ascertained through simulations and verified experimentally for a single‐phase symmetric thirty‐one‐level inverter which shows the proposed converter's ability in smooth sinusoidal output voltage generation with minimum total harmonic distortion.

In this paper, a new structure for symmetric and cascade multilevel converter is presented. This structure requires the least power electronic components, gate driver circuits, power diode, and dc voltage source. The number of output levels is high. Reduction of the number of power electronic switches against voltage levels is an important factor in multilevel converters due to safety in switches, circuit size, cost, installation area, and complexity in control. To maximize the number of output level in the proposed optimized structure in order to attain different goals, such as reduction of stress on switches, the result of comparing the proposed structure and other structures present. The proposed method is robust against the switching faults in multilevel converter for dc source and the equipment. The simulation and experimental results presented in this paper show the performance of the proposed method.

This paper presents a new structure of a multilevel inverter with fewer components, which is suitable for renewable energy sources and industrial loads applications. The structure has three unequal input sources and ten switches that can generate a 15-level output voltage. Furthermore, it can be connected in cascade for increasing, even more, the number of levels and output voltage. The main feature of the proposed inverter is its very low harmonic distortion at the output voltage and current due to the control method, which is based on the nearest level control method for generating a high-quality output voltage. A typical application of this inverter is in solar cells and wind turbines. Both simulations in Matlab/Simulink and experimental results in a scaled-down prototype validate the proposed theoretical analysis.

This paper presents a dual input-port bidirectional DC/DC converter for a Hybrid Energy Storage System (HESS). The converter is non-coupled, non-isolated and it has high-gain. Thus, it does not have transformer or coupling inductances, so voltage spikes or circulating currents are not present which is reflected in its high efficiency. In addition, the DC/DC converter is totally bidirectional, so the sources can transfer the energy between them and to the load. The converter has six switches but only three of them work in each mode, so the control is relatively simple. The main applications of the proposed converter are HESS for DC microgrid applications or small electric vehicles, particularly in which the storage system is small, hence the voltage is low, but the “load” works at a much higher voltage. The article analyses the converter in steady-state and presents the small-signal model, based on that, the control loop is designed. Simulations and experimental results validate the converter.

Power industry is evolving toward high density power and therefore high frequency applications. Converters with low switching losses based on soft switching have been developed. In many of these converters, the transformers that are used, should have tuned magnetizing and leakage inductances. Hence, more accurate design methodologies should be developed. In this paper air-gap, winding overlap coefficient and core geometry are used for designing high frequency transformer with desired magnetizing and leakage inductances. Core geometry is a concept that is used by manufactures to select cores based on their power-handling capability. In this paper, instead of using complex analytical methods or time consuming and expensive FEM simulations, a methodology is proposed that uses few FEM simulations and multi-layer perceptron neural networks for designing specific magnetizing and leakage inductances, for a wide selection of cores. Moreover, the effect of core geometry on magnetizing and leakage inductances is explored. Detailed 3D-FEM simulations confirm the validity of proposed methodology. In addition, a prototype was tested and experimental results are consistent with Neural-network results.