Electric utility industry is currently facing a market deregulated environment and many technological advances. In this context, the demand for electric power having higher network security, better power quality, improved system reliability, and availability is increasing every day. This complex scenario put the electric utilities under conflicting pressure between meeting the growth demands, reducing its operation cost, keeping maintenance and construction and try to provide lower rates for customers or to improve the company profits. Therefore, solutions for planning, design and operation of power systems involve the simultaneous optimization of multiple objectives, often conflicting between them. This work presents the state of the art of multi-objective evolutionary algorithms applications to electrical power systems, in order to provide the power system engineering community with the expertise about the development of multi-objective optimization paradigms and trends in the applications of multi-objective evolutionary algorithms, altogether useful for tackling down every-day electrical networks challenges.

Power boost DC-DC voltage converters have become a key element for medium-voltage DC (MVDC) applications as a link between generation and distribution grids, it is possible to classify the DC-DC converters into four families, depending on their characteristics, as well, one of the actual principal needs is to reduce the number of passive and active components needed for voltage conversions. This article presents a novel transformerles DC-DC boost-resonant converter, which is destined for the interconnection of medium and high voltage DC smart grids. The proposed DC-DC converter is composed of two inductors, a capacitor, and five IGBTs interrupters, which are responsible for the interaction between resonant and boost converters, in the same way, the resonant converter is composed of one resonant inductor and one resonant capacitor while the boost converter is composed by one boost inductor. This paper also presents the operation principle of the proposed converter, as well as its control, modular connection, and simulation to probe the behavior of the converter and an experimental 100 W prototype with 9.5 gain.

This paper presents an isolated DC-DC converter with high voltage gain that features an advanced inter-built nanocrystalline-core medium-frequency transformer (NC-MFT). The isolated DC-DC converter with an NC-MFT is specifically designed for applications such as interconnect photovoltaic (PV) systems, DC microgrids, DC loads, and DC buses, where voltage gain is one of the essential issues to consider. The NC-MFT inside the DC-DC converter is designed with a new approach that not only provides isolation but also contributes to achieving high efficiency and a higher step-up ratio. The high efficiency of the converters contributes to the integration of PV systems into DC microgrids. The converter yields a high voltage conversion ratio of 16.17. The experimental results obtained at 41.8 V/676 V and 275 W for the prototype revealed high efficiency (95.63% at full load). The experimental results validate the theoretical analysis and simulation, confirming that the converter achieves the main objective of high voltage conversion and high efficiency. These results will contribute to the interest in the use of this type of energy and its impact on the reduction in CO₂ emissions.

The power electronic transformer (PET) is an emerging technology that is quickly becoming a key component of the next-to-come power distribution networks (PDNs), due to its versatility on energy management, as well as, the improvement on the quality of the energy. PDNs are characterized by their unbalanced conditions, causing that PETs driven by conventional dq0 controls introduce current distortions on the primary winding of the transformer. Such distortion is evidenced in the 2 $\boldsymbol{\omega }$ oscillations of ${V_d}$ and ${V_q}$ acting as harmonic sources. In this sense, this article proposes a novel control approach for PETs. The key idea behind of this proposal consists of operating each phase independently, which is achieved through the enclosed rectification and the mitigation of the 2 $\boldsymbol{\omega }$ oscillations in a dual active bridge topology. The attained advantages by this control scheme are: a) balancing of the primary winding currents; b) unitary power factor; c) negligible harmonic distortion; and d) 2 $\boldsymbol{\omega }$ oscillation mitigation on the dc bus.

The focus of this paper is to report key aspects of the laboratory-level performance on a three-phase, scaled-down thyristor controlled series capacitor, TCSC, prototype. All-important issues concerned to the design and construction of the prototype are included in this work. The testing of the TCSC prototype is restricted to steady-state conditions. Several experimental cases are presented

Current applications in photovoltaic power generation and energy storage require isolated, efficient, and reliable DC-DC converter topologies. However, the design of the nanocrystalline-core medium-frequency transformer (MFT), as a key element of these isolated topologies, often overlooks the impact of specific operating conditions, such as non-sinusoidal input signals and variations in total harmonic distortion (THD). This work introduces an innovative design method customized for a high-efficiency Central-Tapped medium-frequency transformer (CT-MFT) integrated into a SiC-based central-tapped phase-shift full-bridge (CT-PSFB) converter. Unlike earlier proposals, this work considers key parameters in the transformer design, including non-sinusoidal excitation waveforms and changes in THD during converter operation. After the CT-MFT is designed, the CT-MFT/CT-PSFB structure is simulated and validated using a tailor-made prototype. The experimental results confirm the structure’s effectiveness: the CT-MFT achieves 99.65% efficiency, and the CT-PSFB achieves 94.7% average efficiency, with THD up to 22.5% and 97.66% peak efficiency.