A unified topology for the integration of electric vehicle, renewable energy source, and active filtering for the power quality improvement of the electrical power grid: an experimental validation

Electrical power grids are facing challenges concerning new linked technologies and associated contributions of power electronics, both regarding innovative topologies of power converters and advanced power management algorithms. Additionally, technologies related to renewables and electric mobility have several points in common, especially about the interface with the power grid, which allows to foresee a convergence for unified solutions in the power grid interface, without jeopardizing the functionalities and added values of each technology. Encompassing this purpose, this paper presents a unified topology, based on a three-phase structure, which, in addition to a collaborative operation with the power grid targeting the compensation of power quality problems, also enables the integration of a renewable energy source and an electric vehicle. The main contribution of this paper resides in the fact that only an interface with the power grid is necessary to involve three central features of smart grids: renewables, electric mobility, and power quality. Overall, the unified topology presents a four-quadrant structure, both in the perspective of AC and DC interfaces, offering multiple functionalities, mainly to the power grid. In the AC interface, the structure operates in interleaved mode, while in the DC interface, the structure operates in multilevel mode. The global control algorithm is presented, covering the interconnection between the mentioned technologies, as well as the details of implementation of the individual control algorithms regarding each interface. A laboratory prototype, connected to a three-phase 400 V-50 Hz power grid, was used to obtain an experimental validation for a maximum operating power of 12.5 kW, corroborating the essential advantage characteristics and the correct functioning of the presented unified topology.This work has been supported by FCT—Fundação para a Ciência e Tecnologia within the R&D Units Project Scope: UIDB/00319/2020. This work has been supported by the FCT Project newERA4GRIDs PTDC/EEIEEE/30283/2017 and by the FCT Project DAIPESEV PTDC/EEIEEE/30382/2017

Power electronics technologies and applications for EV battery charging systems

Mainly throughout the last two decades, the technologies associated with electric vehicles (EVs) have achieved a pertinent interest, both in terms of scientific and industrial perspectives [...]This work has been supported by FCT—Fundação para a Ciência e Tecnologia within the R&D Units Project Scope: UIDB/00319/2020. This work has been supported by the FCT Project newERA4GRIDs PTDC/EEIEEE/30283/2017 and by the FCT Project DAIPESEV PTDC/EEIEEE/30382/201

A novel multilevel interleaved-based PFC rectifier with modular DC interfaces

As it has been recognized, mainly over the last decades, PFC rectifiers are more and more fundamental and are increasingly present in several applications in the perspective of limiting power quality problems. In line with this reality, this paper proposes a novel topology of single-phase PFC rectifier. On the AC-side, the proposed PFC rectifier operates with sinusoidal current in phase with the voltage, but, additionally, it presents these very important advantages: Multilevel voltage operation; Interleaved-based current control; Modular design, allowing to establish n DC interfaces on the DC-side. The proposed PFC rectifier is comprehensively detailed, and the validation is carried out with a configuration that allows to have two independent DC interfaces, resulting in an operation with five different voltage levels, and in a current control with a ripple with a frequency that corresponds to four times the value of the switching frequency of each switching device. The validation was carried out addressing the operation of the proposed PFC rectifier in steady-state and transient-state.This work has been supported by FCT - Fundacao para a Ciencia e Tecnologia within the R&D Units Project Scope: UIDB/00319/2020. This work has been supported by the FCT Project newERA4GRIDs PTDC/EEI-EEE/30283/2017

The future of electrical power grids: a direction rooted in power electronics

Electrical power grids are changing with a focus on ensuring energy sustainability and enhanced power quality for all sectors. Over the last few decades, there has been a change from a centralized to a decentralized paradigm, which is the consequence of a large-scale incorporation of new electrical technologies and resultant equipment. Considering the foreseeable continuation of changes in electrical power grids, a direction rooted in power electronics with a focus on hybrid AC/DC grids, including the support of solid-state transformers and unified systems, is presented in this paper. Converging on hybrid AC/DC grids, DC grids (structured as unipolar and bipolar) and coupled and decoupled AC configurations are analyzed. On the other hand, in the context of solid-state transformers, feasible structures are analyzed, including the establishment of hybrid AC/DC grids, and the assessment of gains for boosting power quality is presented. Unified power electronics systems are also of fundamental importance when contextualized within the framework of future power grids, presenting higher efficiency, lower power stages, and the possibility of multiple operations to support the main AC grid. In this paper, such subjects are discussed and contextualized within the framework of future power grids, encompassing highly important and modern structures and their associated challenges. Various situations are characterized, revealing a gradual integration of the cited technologies for future power grids, which are also known as smart grids.This work was supported by FCT—Fundação para a Ciência e Tecnologia within the R&D Units Project Scope: UIDB/00319/2020

Guest editorial: energy storage in smart grids

Energy storage systems and smart grids cooperation is now crucial and will encourage collaborative engagement by different players in the energy market, offering sophisticated management and control approaches. Therefore, new advances and innovative solutions for such cooperation are of preeminent importance. Moreover, electric mobility should also be considered in this scenario. Electric vehicles (EVs) can be seen as distributed energy storage systems that generally need to be charged but, in some cases, can be adopted to support the grid thanks to vehicle-to-grid (V2G) and vehicle-for-grid (V4G) modes, offering advantages of controlled operation with active or reactive power. So, energy storage systems can be distinguished into aggregated and distributed structures, and they can be based on different technologies, such as batteries, fuel-cells, and super-capacitors. Furthermore, the integration of new renewable energy solutions with energy storage systems in smart grids should also be promoted. Power and energy management are crucial for the upcoming challenges and novel opportunities in smart grids. In line with this trend, this Special Issue aims to present further research on and developments in energy storage systems in smart grids, including power electronics converters, novel modulation schemes, energy and power management strategies, advanced battery packs and Battery Management Systems (BMSs). Novel renewable energy solutions are also of interest, as well as their cooperative and strategic integration with storage and EV chargers. Advanced EV services, such as V2G and V4G in the perspective of contributions to improve power quality, can also be considered. Three main topics can be found in this Special Issue: power electronic converters, converter and machine modelling and lithium-ion battery packs. In the following section, the papers accepted per each topic will be rapidly summarized along with their main achievements

Impact of electric vehicles on power quality in a smart grid context

The large dependency of the imported fossil fuels and the soaring oil prices, makes essential the look for alternatives to the traditional people transportation system. The natural bet is the electric mobility, namely Electric Vehicles (EV), and Plug-in Hybrid Electric Vehicles (PHEV). This way, in this paper is analyzed the potential impacts of the battery charging systems on the grid power quality, in a Smart Grid context. It is considered the current consumed, according to a typical electric consumption profile, and the voltage degradation for a large number of houses. Two different types of EV batteries chargers were considered: a traditional charger; and a smart charger with sinusoidal current consumption and unitary power factor. It presents simulation results of the integration of EVs and PHEVs in terms of power quality, and experimental results of a smart charger which was specially developed for EV charging and that allows mitigation of the power quality degradation.Fundação para a Ciência e a Tecnologia (FCT

New operation opportunities for the solid-state transformer in smart homes: a comprehensive aAnalysis

With the expansion of power electronics possibilities for smart homes, new perceptions for power control are emerging, suggesting new possibilities also for smart grids. In this prospect, the solid-state transformer (SST) has a substantial impact to interface smart homes with smart grids, guaranteeing high levels of power quality in both grid (consumed current) and load side (produced voltage). Nevertheless, as advanced contributions, the SST can deal with other possibilities of controllability. In such situation, an analysis of new operation opportunities for the SST into smart homes and smart grid perspectives is offered in this paper. It is discussed the SST principle of operation, with a thorough clarification concerning the proposed control algorithms, as well as an intuitive computational validation contemplating contingencies of operation about power quality effects for the load and grid side. The attained results strengthen the attractiveness of the new operation opportunities for the SST when utilized as interface between homes and smart grids.This work has been supported by FCT -Fundacao para a Ciencia e Tecnologia within the R&D Units Project Scope: UIDB/00319/2020. This work has been supported by the FCT Project newERA4GRIDs PTDC/EEIEEE/30283/2017

Model predictive control of an on-board fast battery charger for electric mobility applications

Under the necessities of reducing emissions and air pollution, and also for increasing fuel economy, automotive companies have been developing electric and plug-in hybrid electric vehicles. Since these vehicles are parked when the batteries are being charged, it is possible to use the traction power converter as on-board charger, also allowing to reduce weight, volume and costs of components in the vehicle. In this context, this paper presents a model predictive control algorithm for an on-board fast battery charging that uses the traction power converter of an electric vehicle. Simulation results and system implementation are depicted, and finally, are presented some experimental results obtained with the proposed control system.(undefined)info:eu-repo/semantics/publishedVersio

Smart transformer: a revolutionary paradigm toward sustainable power grids

Electrical power grids are evolving technologically from different perspectives, specifically, aiming to guarantee the sustainability of the power grid itself, the introduction of new and emerging technologies for the production and storage of energy, advanced communication systems, as well as higher levels of power quality for all sectors of activity (from production to consumption). Particularly, with special focus over the last two decades, power grids are undergoing a depth transformation, moving from a centralized and unidirectional architecture to a decentralized and bidirectional architecture, mainly due to the massive incorporation of new electrical engineering technologies. This change also presents an important aspect for the entire power grid: the possibility of energy storage and management according to the real-time needs. In this context, within the scope of this paper, the sustainability of power grids is considered, focusing on the new paradigms offered by the smart transformer and hybrid AC/DC power grids, including all the added value that can be established in terms of power management. Encompassed in a smart transformer context, the contextualization of the conceivable arrangements of solid-state transformers, and the various configurations of smart hybrid transformers, are evaluated from the point of view of offering advantages of improved efficiency and power quality. In addition to a theoretical introductory context, the paper presents computational validations and a comparison regarding the various configurations that can be obtained

Model predictive control of an on-board fast battery charger for electric mobility applications

Under the necessities of reducing emissions and air pollution, and also for increasing fuel economy, automotive companies have been developing electric and plug-in hybrid electric vehicles. Since these vehicles are parked when the batteries are being charged, it is possible to use the traction power converter as on-board charger, also allowing to reduce weight, volume and costs of components in the vehicle. In this context, this paper presents a model predictive control algorithm for an on-board fast battery charging that uses the traction power converter of an electric vehicle. Simulation results and system implementation are depicted, and finally, are presented some experimental results obtained with the proposed control system.(undefined)info:eu-repo/semantics/publishedVersio