Integrated energy management of plug-in electric vehicles in power grid with renewables

published_or_final_versio

Efficient Digital System Management using IEEE 1451.0 Enabled Control Architecture

The IEEE and National Institute of Standards and Technology have formulated an open universal standard called IEEE 1451 for ‘Smart Transducer Interface’ with digital systems. The objectives of this paper is to propose IEEE 21450 enabled control architectures for efficient management of power system with embedded system parameters as electronic documentation. The control architecture accommodates appropriate number of transducer interface module along with transducer electronic data sheet, which enables active calibration, adaptive tuning and failure proof operation of system management

Digital control of a novel single-phase three-port bidirectional converter to interface renewables and electric vehicles with the power grid

This paper presents the digital control of a novel single-phase three-port bidirectional (STB) converter used to interface renewables from solar photovoltaic (PV) panels and electric vehicles (EVs) with the power grid. Using an appropriated power theory, the STB converter can be used to exchange ener-gy between the PVs, the EVs and the power grid in four distinct modes: (1) The EV receives energy from the power grid (G2V - grid-to-vehicle operation mode) or delivers energy to the power grid (V2G - vehicle-to-grid operation mode); (2) All the energy produced by the PV panels is delivery to the power grid; (3) All the energy produced by the PV panels is delivery to the EV; (4) The EV can receive energy simultaneously from the PV panels and from the power grid (G2V). The currents of the power grid, PV panels and EV are con-trolled through independent predictive current control strategies, which ensure good power quality levels. This paper presents the architecture of the proposed STB converter and the detailed explanation of the digital implementation of the control algorithms, namely, the power theory and the predictive current control strategies. The control algorithms were validated through computational simula-tions and experimental results.Fundação para a Ciência e Tecnologia (FCT); FEDER funds through the COMPETE 2020 – Programa Operacional Competitividade e Internacionalização (POCI) with the reference project POCI-01-0145-FEDER- 006941

A novel converter topology for applications in smart grids: technical and economical evaluation

Technological advances in smart grids significantly contribute to an energy sustainability paradigm, assisting to diminish harms associated with global warming. Some of the key challenges in smart grids are linked with power electronics applications for renewable energy sources (RES), electric mobility (EM), energy storage systems (ESS) and power quality (PQ). These applications for smart grids have a common feature: the requirement to use the full-controlled grid-side power converters. Thereby, this paper aims to contribute with a technical and economical evaluation about a novel topology of the grid-side power converter for applications in smart grids. In terms of technical features, the proposed converter is classified as: (a) Bidirectional, allowing a bidirectional power flow with the electrical grid; (b) Symmetrical, allowing the operation with two distinct applications in the dc-side (e.g., RES, ESS, or EM); (c) Multilevel with nine levels, allowing high levels of PQ for the grid-side. With the objective to establish an accurate case-study, throughout the paper, the technical and economical evaluation is also performed based on the comparison between the proposed topology and the conventional ones. Considering an economical evaluation, the paper presents a cost estimation study concerning the implementation costs of the proposed topology, assuming realistic conditions of operation for applications in smart grids. Based on the entire evaluation for a real operating power range, the obtained results show the operational convenience of the topology in accordance with different applications in smart grids.This work has been supported by FCT – Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/2019. 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.Mr. Tiago Sousa is supported by the doctoral scholarship SFRH/BD/134353/2017 granted by the Portuguese FCT agency. This work is part of the FCT project POCI-01-0145-FEDER-030283

Model predictive current control of a proposed single-switch three-level active rectifier applied to EV battery chargers

This paper presents a model predictive current control applied to a proposed new topology of single-switch three-level (SSTL) active rectifier, which is exemplified in an application of single-phase battery charger for electric vehicles (EVs). During each sampling period, this current control scheme selects the state of the SSTL active rectifier that minimizes the error between the grid current and its reference. Using this strategy it is possible to obtain sinusoidal grid currents with low total harmonic distortion and unitary power factor, which is one of the main requirements for EVs chargers. The paper presents in detail the principle of operation of the SSTL active rectifier, the digital control algorithm and the EV battery charger (where is incorporated the SSTL active rectifier) that was used in the experimental verification. The obtained experimental results confirm the correct application of the model predictive current control applied to the proposed SSTL active rectifier.This work was supported in part by the FCT–Fundação para a Ciência e Tecnologia in the scope of the project: PEst UID/CEC/00319/2013. Vítor Monteiro was supported by the scholarship SFRH/BD/80155/2011 granted by the FCT agency

New opportunities and perspectives for the electric vehicle operation in smart grids and smart homes scenarios

New perspectives for the electric vehicle (EV) operation in smart grids and smart homes context are presented. Nowadays, plugged-in EVs are equipped with on-board battery chargers just to perform the charging process from the electrical power grid (G2V – grid-to-vehicle mode). Although this is the main goal of such battery chargers, maintaining the main hardware structure and changing the digital control algorithm, the on-board battery chargers can also be used to perform additional operation modes. Such operation modes are related with returning energy from the batteries to the power grid (V2G- vehicle-to-grid mode), constraints of the electrical installation where the EV is plugged-in (iG2V – improved grid-tovehicle mode), interface of renewables, and contributions to improve the power quality in the electrical installation. Besides the contributions of the EV to reduce oil consumption and greenhouse gas emissions associated to the transportation sector, through these additional operation modes, the EV also represents an important contribution for the smart grids and smart homes paradigms. Experimental results introducing the EV through the aforementioned interfaces and operation modes are presented. An on-board EV battery charger prototype was used connected to the power grid for a maximum power of 3.6 kW.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 Ǧ 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

Optimal scheduling of PEV charging/discharging in microgrids with combined objectives

While renewable power generation and vehicle electrification are promising solutions to reduce greenhouse gas emissions, it faces great challenges to effectively integrate them in a power grid. The weather-dependent power generation of renewable energy sources, such as Photovoltaic (PV) arrays, could introduce significant intermittency to a power grid. Meanwhile, uncontrolled PEV charging may cause load surge in a power grid. This paper studies the optimization of PEV charging/discharging scheduling to reduce customer cost and improve grid performance. Optimization algorithms are developed for three cases: 1) minimize cost, 2) minimize power deviation from a pre-defined power profile, and 3) combine objective functions in 1) and 2). A Microgrid with PV arrays, bi-directional PEV charging stations, and a commercial building is used in this study. The bi-directional power from/to PEVs provides the opportunity of using PEVs to reduce the intermittency of PV power generation and the peak load of the Microgrid. Simulation has been performed for all three cases and the simulation results show that the presented optimization algorithms can meet defined objectives

Continuous control set model predictive control of a bridgeless-boost three-level active rectifier

Over the past few decades, active rectifiers have assumed an important preponderance for numerous applications that propose to minimize power quality problems. Consequently, digital control algorithms are following this trend by contributing with a significant set of advantages. This paper presents the use of a continuous control set model predictive control (CCS-MPC) for a bridgeless-boost three-level (BB3L) active rectifier. The BB3L has a set of advantages when confronted with traditional solutions to improve power quality, where the possibility to operate with three voltage levels, sinusoidal current and unitary power factor, while using few switching devices, are the main features. Considering the multiplicity of applications for the BB3L active rectifier, the CCS-MPC is applied to obtain a robust current tracking. The BB3L is presented in detail throughout the paper and based on its mathematical model, the digital control equations are formulated, highlighting that the possibility of operating with a fixed switching frequency is the main characteristic. The results are achieved for many operating conditions, covering steady-state and transient-state, validating the accurate application of the CCS-MPC.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/EEI-EEE/30283/2017. Tiago J. C. Sousa is supported by the doctoral scholarship SFRH/BD/134353/2017 granted by FCT

Sliding mode control of an innovative single-switch three-level active rectifier

This paper presents the sliding mode control (SMC) applied to an innovative active rectifier. This proposed active rectifier is constituted by a single-switch, and operates with three voltage levels, evidencing a set of advantages when compared with conventional approaches of power factor correction topologies. Taking into account the diversity of applications for this type of power converter, the SMC is used in order to obtain a robust current tracking. Since the active rectifier is controlled according to the ac grid-side current, the error between such current and its reference is determined, and by employing the SMC, this error is minimized during each sampling period with the objective of selecting the state of the single-switch. A comprehensive description about the SMC implementation, supported by the overall operation of the active rectifier, is presented throughout the paper. The obtained computational results for a set of different operating conditions, comprising significant power ranges and sudden variations, confirm the accurate application of the SMC when applied to the proposed single-switch three-level active rectifier. A comparison is also established with other current control, allowing to confirm the precise application of the SMC strategy.This work has been supported by FCT – Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/2019. This work has been supported by FCT Project newERA4GRIDs PTDC/EEI-EEE/30283/2017, and by the FCT Project DAIPESEV PTDC/EEI-EEE/30382/2017. Tiago Sousa is supported by the doctoral scholarship SFRH/BD/134353/2017 granted by FCT

A novel multilevel converter for on-grid interface of renewable energy sources in smart grids

The on-grid interface of renewable energy sources involves a dc-ac converter for controlling the injected current. In this perspective, a novel topology of grid-tied converter is proposed, assuming as main feature the produced multilevel voltages (five-levels). The proposed grid-tied converter is intended for on-grid interfaces, which is controlled for guaranteeing sinusoidal currents for all grid voltage conditions. The dc-side can be linked directly to a dc-to-dc intermediary converter, responsible for interfacing renewable energy sources, as solar photovoltaic or wind power systems. Throughout the paper, a complete examination of the operation principle and the adopted control theory, including current control, as well as hardware project, are comprehensively presented. An accurate computational simulation validation is presented, comprising realistic operating conditions in terms of grid voltage disturbances and operating power. The obtained results prove the advantages of the proposed grid-tied multilevel converter, and establish a comparison with the classical solutions.This work has been supported by FCT – Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/2019. This work has been supported by FCT Project newERA4GRIDs PTDC/EEI-EEE/30283/2017, and by the FCT Project DAIPESEV PTDC/EEI-EEE/30382/2017. Tiago Sousa is supported by the doctoral scholarship SFRH/BD/134353/2017 granted by FCT