With the expansion of renewable energy sources worldwide, the need for developing more economical and more efficient converters that can operate on a high frequency with minimal switching and conduction losses has been increased. In power electronic converters, achieving high efficiency is one of the most challenging targets to achieve. The utilization of wideband switches can achieve this goal but add additional cost to the system. LLC resonant converters are widely used in different applications of renewable energy systems, i.e., PV, wind, hydro and geothermal, etc. This type of converter has more benefits than the other converters such as high electrical isolation, high power density, low EMI, and high efficiency. In this paper, a comparison between silicon carbide (SiC) MOSFET and silicon (Si) MOSFET switches was made, by considering a 3KW half-bridge LLC converter with a wide range of input voltage. The switching losses and conduction losses were analyzed through mathematical calculations, and their authenticity was validated with the help of software simulations in PSIM. The results show that silicon carbide (SiC) MOSFETs can work more efficiently, as compared with silicon (Si) MOSFETs in high-frequency power applications. However, in low-voltage and low-power applications, Si MOSFETs are still preferable due to their low-cost advantage.

In renewable energy sources, specifically in photovoltaics systems, DC/DC converters play vital roles, as the power generated by PV systems is non-linear and changes with solar irradiance and temperature. Therefore, these systems require converters that have wide input voltage range, high voltage gain, high power range and improved efficiency. In this paper, analysis of non-isolated reduced redundant power processing converter topology is presented to evaluate its efficiency and reliability for the photovoltaic system. The proposed converter has very simple design and a low number of circuit elements. The converter is designed in such a way that it always operates in continuous conduction mode. The mathematical modeling of a 3 kW converter is presented to show the theoretical evaluation of the step-up voltage ratio of the converter. For further evaluation of the performance and efficiency of the converter, a simulation study is conducted in PSIM software. Overall converter efficiency is improved for a wide input voltage range and voltage gain, specifically for photovoltaic systems.

With the growth of renewable energy sources around the world, the demand for cost-effective and efficient converters that can operate at high frequency and have less switching and conduction loss has grown. High efficiency is one of the most difficult goals to attain in power electronic converters. Wideband switches can be used to achieve this purpose, although they add to the system’s cost. In this paper, a comparison between SiC MOSFET and Si MOSFET switches was carried out for a 3 KW I-IIB Buck-boost/Boost non-isolated reduced redundant converter for the photovoltaic system with a wide input voltage range. Mathematical calculations were used to investigate switching and conduction losses, and software simulations in PSIM were used to verify their authenticity. In high-frequency power applications, the results suggest that SiC MOSFET can work more efficiently than Si MOSFET. Si MOSFETs, on the other hand, are still preferred for small voltage and low power applications due to their lower costs.

Due to rapid increase in the installation of renewable energy resources in the grid, the use of power electronic-based devices is increasing day by day. Whenever a wind farm is installed and integrated with the grid, most of the work and control depends on its electronic converters. Whenever a grid fault occurs, it can cause significant overcurrents and overvoltage, placing the entire facility at risk. It can quickly cause the converter system to deteriorate if countermeasures are not taken. Thus, a proper protection scheme is needed to protect the generator and its converter from faults. In this paper, an asymmetrical fault analysis and protection scheme is presented in which a single line to ground fault is created, followed by a check of its effects on the DFIG, rotor circuit and converters. Then, a proper protection scheme for a crowbar circuit is designed and we assess its operation on a 1.5 MW DFIG-based industrial wind turbine model in EMTDC/PSCAD.

Due to the increase in renewable energy resources the need for highly efficient power electronics converters at flexible operating conditions has increased. The newly introduced wide bandgap switches, such as Gallium Nitride (GaN) are more suitable mechanically, thermally, and in terms of fast switching, etc. In this paper, a 3kW LLC resonant converter was designed for PV applications using GaN as switching devices. The converter was designed to achieve zero voltage switching at a wide input voltage range. The proposed system was simulated on PSIM software under different loading conditions. A performance comparison was made between GaN and Si switches. Analysis shows that the GaN converter has better performance compared to Si at higher voltages. The designed converter achieved 98.55% maximum efficiency.

The restoration of power systems is emphasized in the modern electric power system (EPS) due to complex, interconnected networks, and natural catastrophic events. However, large-scale disruptions in the power system result in a partial or complete blackout. Such events have a low probability and high impact, causing significant regional socio-economic losses. Hence, the black start (BS) resource is needed to deliver the cranking power to restart the non-black start (NBS) units, energize the path, load, and restore the complete system with parallel restoration. This paper implemented a novel optimal restoration scheme to restore the power system after partial or complete blackout. A multi-objective genetic algorithm is used to solve each island’s optimal generation unit’s start-up sequence, priority start of critical load and restoring the maximum load in minimum restoration time using an optimal transmission path with a minimum number of switching actions. A case study based on the IEEE-39 benchmark system validates the effectiveness of the proposed algorithm.