Comparative analysis between different approaches for single-phase PLLs

"In press"This paper presents a comparative analysis between two distinct synchronizing circuits, which are usually applied as the core of control algorithms for single-phase power quality applications. One of these synchronizing circuits corresponds to a single-phase Phase-Locked Loop (PLL), implemented in α-β coordinates (αβ-PLL), whereas the other one corresponds to the Enhanced PLL (E-PLL). The major contribution of this paper is to present a single-phase PLL oriented to power quality applications, with a very simple structure, capable to be synchronized with the fundamental component of an input signal (voltage or current), even considering substantial disturbances, such as, frequency deviations, phase shifts, harmonic components and amplitude variations. Simulation and experimental results, involving these two synchronizing circuits submitted to three different test cases, are provided in order to compare their transient and steady-state performance. Moreover, it is also presented a comparison involving the processing speed and memory requirements of these synchronizing circuits in the DSP TMS320F28335

A flexible infrastructure for dynamic power control of electric vehicle battery chargers

This paper proposes a Flexible Infrastructure for Dynamic Power Control (FIDPC) of Electric Vehicle (EV) Battery Chargers. This infrastructure dynamically adjusts the EV battery charger current, according to the power demand of the home wherein the vehicle is plugged. An infrastructure was implemented to validate this proposal. Such infrastructure is composed by an EV battery charger and a communication system based on a Radio Frequency interface. The battery charger has nominal power of 3.6 kVA and operates with sinusoidal current and unitary total power factor, while the RF interface provides continuous data flow to the battery charger with information about the home total current consumption (rms value). Experimental tests were performed under realistic conditions to validate the concept behind the proposed FIDPC. These tests served to assess the behavior of the EV battery charger with dynamic power control on a single-phase, 230 V, 16 A, 50 Hz residential electrical installation. The experimental results confirm the quick time response of the FIDPC even when working under heavy home load variations.This work was supported by the Fundacao para a Ciencia e Tecnologia (FCT) through Project PEst-UID/CEC/00319/2013. The work of V. Monteiro was supported by the FCT agency through a doctoral scholarship under Grant SFRH/BD/80155/2011. The review of this paper was coordinated by Dr. D. Cao

Operation modes for the electric vehicle in smart grids and smart homes: present and proposed modes

This paper presents the main operation modes for an electric vehicle (EV) battery charger framed in smart grids and smart homes, i.e., are discussed the present-day and are proposed new operation modes that can represent an asset towards EV adoption. Besides the well-known grid to vehicle (G2V) and vehicle to grid (V2G), this paper proposes two new operation modes: Home-to-vehicle (H2V), where the EV battery charger current is controlled according to the current consumption of the electrical appliances of the home (this operation mode is combined with the G2V and V2G); Vehicle-for-grid (V4G), where the EV battery charger is used for compensating current harmonics or reactive power, simultaneously with the G2V and V2G operation modes. The vehicle-to-home (V2H) operation mode, where the EV can operate as a power source in isolated systems or as an off-line uninterruptible power supply to feed priority appliances of the home during power outages of the electrical grid is presented in this paper framed with the other operation modes. These five operation modes were validated through experimental results using a developed 3.6 kW bidirectional EV battery charger prototype, which was specially designed for these operation modes. The paper describes the developed EV battery charger prototype, detailing the power theory and the voltage and current control strategies used in the control system. The paper presents experimental results for the various operation modes, both in steady-state and during transients

Improved vehicle-for-grid (iV4G) mode: novel operation mode for EVs battery chargers in smart grids

The experimental validation of a novel operation mode for electric vehicles (EVs) to support the grid power quality is presented. The proposed operation mode, denominated improved vehicle-for-grid (iV4G), is directly associated with the EVs operation aiming the compensation of power quality problems associated with current harmonic distortion and reactive power, improving the total power factor of the electrical installation. Simultaneously with the proposed iV4G, where the EV injects current harmonics and provides reactive power, the EV can exchange active power with the grid (grid-to-vehicle, G2V, to charge the batteries or vehicle-to-grid, V2G, to deliver energy back to the power grid). In this paper, the proposed iV4G operation mode is experimentally validated with a developed EV battery charger prototype connected to an electrical installation of 230 V, 16 A, 50 Hz. The control strategies of the iV4G operation mode and the used prototype are described in detail along the paper. The achieved results confirm the feasibility and good performance of the proposed iV4G operation mode, working alone, and also when associated with the G2V and V2G operating modes.This work has been supported by FCT project 0302836 NORTE-01-0145-FEDER-030283. This work is also part of the COMPETE: POCI-01-0145-FEDER-007043 and FCT within the Project Scope: UID/CEC/00319/2013. This work isfinanced by the ERDF–European RegionalDevelopment Fund through the Operational Programme forCompetitiveness and Internationalisation–COMPETE 2020Programme, and by National Funds through the Portuguese fundingagency, FCT, within project SAICTPAC/0004/2015–POCI–01–0145–FEDER–016434

Experimental validation of a three-port integrated topology to interface electric vehicles and renewables with the electrical grid

This paper presents the analysis and the experimental validation of an off-board three-port integrated topology (TPIT) used to interface electric vehicles (EVs) and renewables from solar photovoltaic (PV) panels with the electrical power grid. The TPIT is composed by three power converters sharing a single common dc-link, and it can operate in four different modes towards the future smart grids: (1) The EV batteries are charged with energy from the electrical power grid through the grid-to-vehicle (G2V) operation mode; (2) The EV batteries deliver part of the stored energy back to the power grid through the vehicle-to-grid (V2G) operation mode; (3) The energy produced by the PV panels is delivered to the electrical grid through the renewable-to-grid (R2G) operation mode; (4) The energy produced by the PV panels is used to charge the EV batteries through the renewable-to-vehicle (R2V) operation mode. In addition to individual action, the reorganization of these modes results in new combined operation modes. The paper presents the proposed power theory to control the TPIT, the current control strategies to manage the currents in ac and dc sides of the TPIT, and the details of the developed TPIT prototype, including the hardware and the digital control system. Experimental results that validate the TPIT operation modes are also presented.This work has been supported by FCT – Fundação para a Ciência e Tecnologia in the scope of the project: PEstUID/CEC/00319/2013. This work has been supported by COMPETE: POCI-01-0145-FEDER-007043 and FCT – Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/2013. This work is financed by the ERDF – European Regional Development Fund through the Operational Programme for Competitiveness and Internationalisation ‐ COMPETE 2020 Programme, and by National Funds through the Portuguese funding agency, FCT ‐ Fundação para a Ciência e a Tecnologia, within project SAICTPAC/0004/2015‐ POCI‐ 01‐0145‐FEDER‐016434.info:eu-repo/semantics/publishedVersio

Bidirectional multilevel converter for electric vehicles

In this paper is presented an H-Bridge Multilevel Converter topology for Electric Vehicles (EVs) and Plug-in Hybrid Electric Vehicles (PHEVs). The topology of the presented multilevel converter allows the interface between the batteries, the electric motor of the vehicle, and the electrical power grid. Thereby, taking into account that the proposed multilevel converter requires the use of isolated voltage sources, the interface between the batteries and the multilevel converter is evaluated regarding the converter operation as a Battery Management System (BMS), controlling the charging and discharging processes. The interface between the multilevel converter and the electrical power grid is described considering a bidirectional operation. These modes of operation occur during the batteries charging process, denominated as Grid-to-Vehicle (G2V), and during the operation as Vehicle-to-Grid (V2G), that consists in delivering back to the electrical power grid a small amount of the energy stored in the batteries, in accordance with the electrical grid requirements and with the vehicle driver accordance. In both modes of operation, the waveform of the AC current of the electrical power grid is kept sinusoidal with unitary power factor, contributing to maintain a good level of power quality.FEDER Funds - Operational Programme for Competitiveness Factors (COMPETE)Fundação para a Ciência e a Tecnologia (FCT) - PTDC/EEA-EEL/104569/2008, MITPT/ EDAM-SMS/0030/200

Decision process to manage renewable energy production in smart grid environment

This research work is related to the Electric Vehicle (EV) integration in the electricity market, using the OpenADR open protocol for demand response. The proposed solution integrates a local developed EV charging system and a cloud management system, to coordinate the available energy produced from renewable energy sources, taking into account its intermittent production and the requirements of the EV charging process at home. Considering the smart mobility paradigm, all transactions processes are available at mobile devices in real-time, where users can define their usual behavior, configure the energy consumption profile at home, establish new profiles for specific days according to the EV charging process, and consult the historical transactions.This work has been supported by COMPETE: POCI-01-0145-FEDER-007043 and FCT – Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/2013.info:eu-repo/semantics/publishedVersio

Pharmacological potential of methylxanthines: Retrospective analysis and future expectations

Methylated xanthines (methylxanthines) are available from a significant number of different botanical species. They are ordinarily included in daily diet, in many extremely common beverages and foods. Caffeine, theophylline and theobromine are the main methylxanthines available from natural sources. The supposedly relatively low toxicity of methylxanthines, combined with the many beneficial effects that have been attributed to these compounds through time, generated a justified attention and a very prolific ground for dedicated scientific reports. Methylxanthines have been widely used as therapeutical tools, in an intriguing range of medicinal scopes. In fact, methylxanthines have been/were medically used as Central Nervous System stimulants, bronchodilators, coronary dilators, diuretics and anti-cancer adjuvant treatments. Other than these applications, methylxanthines have also been hinted to hold other beneficial health effects, namely regarding neurodegenerative diseases, cardioprotection, diabetes and fertility. However, it seems now consensual that toxicity concerns related to methylxanthine consumption and/or therapeutic use should not be dismissed. Taking all the knowledge and expectations on the potential of methylxanthines into account, we propose a systematic look at the past and future of methylxanthine pharmacologic applications, discussing all the promise and anticipating possible constraints. Anyways, methylxanthines will still substantiate considerable meaningful research and discussion for years to come.info:eu-repo/semantics/publishedVersio

Smart charging management for electric vehicle battery chargers

This paper proposes a smart battery charging strategy for Electric Vehicles (EVs) targeting the future smart homes. The proposed strategy consists in regulate the EV battery charging current in function of the total home current, aiming to prevent overcurrent trips in the main switch breaker. Computational and experimental results were obtained under real-time conditions to validate the proposed strategy. For such purpose was adapted a bidirectional EV battery charger prototype to operate in accordance with the aforementioned strategy. The proposed strategy was validated through experimental results obtained both in steady and transient states. The results show the correct operation of the EV battery charger even under heavy load variations.Fundação para a Ciência e Tecnologia within the Project Scope: PEst - OE/EEI/UI0319/201

iV2G charging platform

This paper describes an intelligent Vehicle to Grid (iV2G) Charging Platform for plug-in hybrid and electric vehicles that can be used at user’s home, and which includes a mobile control system. The car drivers can control remotely the charging or discharging process through a mobile communication device. This mobile communication device can also gather information about charging places, their availability and the best road paths to reach them, as well as energy market prices, informing the best periods to charge the car regarding the energy costs.Fundação para a Ciência e a Tecnologia (FCT