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The use of power electronic converters is essential for the operation of Switched Reluctance Machines (SRMs). Many topologies and structures have been developed over the last years considering several specific applications for this kind of machine, improving the control strategies, performance range, fault-tolerant operation, among other aspects. Thus, due to the great importance of power electronic converters in such applications, this paper is focused on a detailed review of main structures and topologies for SRM drives. The proposed study is not limited to the classic two-level power converters topologies dedicated to the SRMs; it also presents a review about recent approaches, such as multilevel topologies and based on impedance source network. Moreover, this review is also focused on a new class of topologies associated to these machines, namely the ones with fault-tolerant capability. This new category of topologies has been a topic of research in recent years, being currently considered an area of great interest for future research work. An analysis, taking into consideration the main features of each structure and topology, was addressed in this review. A classification and comparison of the several structures and topologies for each kind of converter, considering modularity, boost capability, number of necessary switches and phases, integration in the machine design, control complexity, available voltage levels and fault-tolerant capability to different failure modes, is also presented. In this way, this review also includes a description of the presented solutions taking into consideration the reliability of the SRM drive.
Vitor Fernão Pires; Armando José Pires; Armando Cordeiro; Daniel Foito. A Review of the Power Converter Interfaces for Switched Reluctance Machines. Energies 2020, 13, 3490 .
AMA StyleVitor Fernão Pires, Armando José Pires, Armando Cordeiro, Daniel Foito. A Review of the Power Converter Interfaces for Switched Reluctance Machines. Energies. 2020; 13 (13):3490.
Chicago/Turabian StyleVitor Fernão Pires; Armando José Pires; Armando Cordeiro; Daniel Foito. 2020. "A Review of the Power Converter Interfaces for Switched Reluctance Machines." Energies 13, no. 13: 3490.
Multi-motor driving servomechanisms are widely used in modern industry for high-performance applications involving synchronized control of position, speed, acceleration and deceleration. Several synchronous control schemes have been developed to achieve good speed or position tracking regardless of various uncertainties and load torque perturbations. However, these solutions have some disadvantages, namely the costs associated with the necessary interfaces to transmit hardware synchronization signals between multiple drives and difficulty to integrate other tools and communication networks. Recently, Industrial Ethernet network-based control systems are becoming increasingly popular for industrial applications and factory automation. To overcome some of these disadvantages this paper proposes an approach that uses a real-time Ethernet applied to a dual-motor master-slave synchronization system, without introducing significant degradation of speed or position in the application performance. With this solution the position reference from the master encoder is transmitted by the real-time Ethernet instead of the classic hardware interface. This allows the integration of different tools and the explore of other functionalities of electric drives. The performance of the proposed solution was tested using industrial equipment through several practical experiments. It was also compared with an existing solution based on hardware interfaces, to identify advantages, limitations and cost savings of using real-time Ethernet networks solutions in synchronized AC electric drives.
Armando Cordeiro; José F.M. Manuel; Vítor Fernão Pires. Performance of synchronized master-slave closed-loop control of AC electric drives using real time motion over ethernet (RTMoE). Mechatronics 2020, 69, 102400 .
AMA StyleArmando Cordeiro, José F.M. Manuel, Vítor Fernão Pires. Performance of synchronized master-slave closed-loop control of AC electric drives using real time motion over ethernet (RTMoE). Mechatronics. 2020; 69 ():102400.
Chicago/Turabian StyleArmando Cordeiro; José F.M. Manuel; Vítor Fernão Pires. 2020. "Performance of synchronized master-slave closed-loop control of AC electric drives using real time motion over ethernet (RTMoE)." Mechatronics 69, no. : 102400.
The power electronic converter design is essential for the operation of the switched reluctance motor (SRM). Thus, a fault-tolerant power converter is fundamental to ensure high reliability and extend the drive operation. To achieve fault tolerance, fault detection and diagnosis methods are critical in order to identify, as soon as possible, the failure mode of the drive. To provide such capability, it is proposed in this paper a new fault-tolerant power converter scheme combined with a fault detection method regarding the most common power semiconductors failures in SRM drives. The fast and reliable proposed diagnosis method is based on the entropy theory. Based on this theory, normalized indexes (diagnostic variables) are created, which are independent from the load and speed of the motor. Through this method, it is possible to identify the faulty leg, as well as the type of power semiconductor fault. To test and evaluate the proposed solution several laboratory experiments were carried out using a 2 kW four-phase 8 / 6 SRM.
Vitor F. Pires; Tito G. Amaral; Armando Cordeiro; Daniel Foito; Armando J. Pires; João F. Martins. Fault-Tolerant SRM Drive with a Diagnosis Method Based on the Entropy Feature Approach. Applied Sciences 2020, 10, 3516 .
AMA StyleVitor F. Pires, Tito G. Amaral, Armando Cordeiro, Daniel Foito, Armando J. Pires, João F. Martins. Fault-Tolerant SRM Drive with a Diagnosis Method Based on the Entropy Feature Approach. Applied Sciences. 2020; 10 (10):3516.
Chicago/Turabian StyleVitor F. Pires; Tito G. Amaral; Armando Cordeiro; Daniel Foito; Armando J. Pires; João F. Martins. 2020. "Fault-Tolerant SRM Drive with a Diagnosis Method Based on the Entropy Feature Approach." Applied Sciences 10, no. 10: 3516.
Reliability in the electrical drives is becoming an important issue in many applications. In this context, the reliability associated to the switched reluctance machine (SRM) is also an important area of research. One of the major problems, that strongly affect its operation, are drive power semiconductors faults. Typical power converter topologies used in SRM drives cannot handle faults in their power semiconductors. So, this paper presents a power converter topology that provides fault-tolerant capabilities to the drive under a switch fault. This power converter will be used considering that a change in the direction of the current that flows in the SRM windings does not affect the behavior of the machine. Besides that, the proposed power converter will allow to generate multilevel phase voltages in order to apply different voltage levels as function of the SRM speed. A laboratory power converter was developed to test the SRM drive in normal and faulty conditions. From the obtained results it was possible to verify the fault-tolerant capability of the drive under switch faults in different devices and failure modes. It was also possible to confirm the multilevel operation of the drive.
V. Fernao Pires; Armando Cordeiro; Daniel Foito; A. J. Pires; J. F. Martins; Hao Chen. A Multilevel Fault-Tolerant Power Converter for a Switched Reluctance Machine Drive. IEEE Access 2020, 8, 21917 -21931.
AMA StyleV. Fernao Pires, Armando Cordeiro, Daniel Foito, A. J. Pires, J. F. Martins, Hao Chen. A Multilevel Fault-Tolerant Power Converter for a Switched Reluctance Machine Drive. IEEE Access. 2020; 8 (99):21917-21931.
Chicago/Turabian StyleV. Fernao Pires; Armando Cordeiro; Daniel Foito; A. J. Pires; J. F. Martins; Hao Chen. 2020. "A Multilevel Fault-Tolerant Power Converter for a Switched Reluctance Machine Drive." IEEE Access 8, no. 99: 21917-21931.
In this paper, the development of an educational tool to improve the learning process about electrical power distribution and utilization systems in power system courses is presented. Usually, power system courses cover several concepts from the generation of electrical energy, transportation, interconnection, transformation, protection, distribution to final consumption. Most concepts are taught using theoretical circuit analysis, mathematical models and simulations in the classroom and laboratories. To improve the learning of some concepts, some technical tours to power stations and substations are made whenever possible. However, experimental exercises in power system courses are very difficult to implement due to safety reasons since most power equipment operates with high voltages. To mitigate this problem and motivate students in this area, a new power system educational tool to simulate electrical power distribution and utilization systems is proposed. The proposed system was developed using a Programmable Logic Controller (PLC) and other industrial equipment. The proposed pedagogical activities of the educational project and the results achieved with this new update are discussed in this study.
Armando Cordeiro; Vitor Fernao Pires. A Remote and On-Site Educational Tool to Improve the Learning Process of Electrical Power Distribution and Utilization Systems. IEEE Transactions on Power Systems 2019, 35, 2144 -2154.
AMA StyleArmando Cordeiro, Vitor Fernao Pires. A Remote and On-Site Educational Tool to Improve the Learning Process of Electrical Power Distribution and Utilization Systems. IEEE Transactions on Power Systems. 2019; 35 (3):2144-2154.
Chicago/Turabian StyleArmando Cordeiro; Vitor Fernao Pires. 2019. "A Remote and On-Site Educational Tool to Improve the Learning Process of Electrical Power Distribution and Utilization Systems." IEEE Transactions on Power Systems 35, no. 3: 2144-2154.
This paper presents a new three-phase battery charger integrated with the propulsion system of an electric vehicle. The propulsion system consists of a dual-inverter topology connected to an induction motor via open windings. The electrical vehicles (EV) batteries are divided by two inverters. This will result in a drive with multilevel characteristics reducing the total harmonic distortion (THD) of the voltage applied to the motor. The modularity of the multilevel inverter will be maintained since two classical three-phase inverters are used. The charger will be fed by a three-phase high power factor current source rectifier. The motor windings will take the role of the DC-inductor required by the rectifier. In this way, an intermediate storage element between the grid and the batteries of the vehicle exist. For the control system of the battery charger, we propose the use of the instantaneous power theory and a sliding mode controller for the three-phase charger input currents. Finally, to verify the behavior and characteristics of the proposed integrated battery charger and control system, several tests are be presented.
Vitor Fernão Pires; Joaquim Monteiro; Armando Cordeiro; José Fernando Silva. Integrated Battery Charger for Electric Vehicles Based on a Dual-Inverter Drive and a Three-Phase Current Rectifier. Electronics 2019, 8, 1199 .
AMA StyleVitor Fernão Pires, Joaquim Monteiro, Armando Cordeiro, José Fernando Silva. Integrated Battery Charger for Electric Vehicles Based on a Dual-Inverter Drive and a Three-Phase Current Rectifier. Electronics. 2019; 8 (10):1199.
Chicago/Turabian StyleVitor Fernão Pires; Joaquim Monteiro; Armando Cordeiro; José Fernando Silva. 2019. "Integrated Battery Charger for Electric Vehicles Based on a Dual-Inverter Drive and a Three-Phase Current Rectifier." Electronics 8, no. 10: 1199.
Microgrids are about to change the architecture and the operation principles of the future power systems towards smartness and resiliency. Power electronics technologies are key enablers for novel solutions. In this paper we analyze the benefits of a “microgrid by design” architecture (MDA), using a solid-state transformer (SST) as a low-voltage grid-former and inverter-based generation only. In this context, the microgrid stability is maintained with the help of “electrostatic energy inertia” that can be provided by the capacitor connected to the DC busbar behind the SST inverter topology. This happens in a natural way, alike the mechanical inertia in power systems with synchronous machines, however without depending on frequency and without the need of a rotational inertia. This type of microgrid always operates (both fully connected to the main grid or in islanding mode) with all the necessary mechanisms needed to maintain the microgrid stable—no matter of the perturbations in the upstream of the point of common coupling (PCC). In the case of microgrids with inverter-based generation only (including the energy storage systems), there is no mechanical inertia and different stability mechanisms need to be applied compared to the stability principle of the classical power systems. Our proposed mechanism differentiates from the recently proposed stability assessments of microgrids based on virtual synchronous generators from the control theory perspective. This paper is a continuation of our previous work where the MDA was first introduced. The use-cases and scenarios are based on realistic and yet reasonable complexities, by coupling the disturbance magnitude with the voltage stability limit in power grids. The paper finds meaningful disturbances to test the electrostatic energy inertia at the boundaries of grid stability, as guidance to understand the range of voltage variation for extreme conditions. The results show that in microgrids with inverter-based generation only and passive loads (RLC type) the operation is no longer frequency dependent. The energy of the DC busbar capacitor as electrostatic energy inertia of the MDA has a role similar to that of the rotational machines in classical grids in terms of maintaining dynamic stability, however impacting two different types of stability.
Mihai Sanduleac; Lucian Toma; Mircea Eremia; Irina Ciornei; Constantin Bulac; Ion Triștiu; Andreea Iantoc; João F. Martins; Vitor F. Pires. On the Electrostatic Inertia in Microgrids with Inverter-Based Generation Only—An Analysis on Dynamic Stability. Energies 2019, 12, 3274 .
AMA StyleMihai Sanduleac, Lucian Toma, Mircea Eremia, Irina Ciornei, Constantin Bulac, Ion Triștiu, Andreea Iantoc, João F. Martins, Vitor F. Pires. On the Electrostatic Inertia in Microgrids with Inverter-Based Generation Only—An Analysis on Dynamic Stability. Energies. 2019; 12 (17):3274.
Chicago/Turabian StyleMihai Sanduleac; Lucian Toma; Mircea Eremia; Irina Ciornei; Constantin Bulac; Ion Triștiu; Andreea Iantoc; João F. Martins; Vitor F. Pires. 2019. "On the Electrostatic Inertia in Microgrids with Inverter-Based Generation Only—An Analysis on Dynamic Stability." Energies 12, no. 17: 3274.
One of the main power quality issues that can affect variable speed drives (VSDs) is the occurrence of voltage sags on their AC power supply. Voltage sags can affect the inverter nominal operation, leading to a malfunction of the AC motor. This paper presents an inverter with resilient capability to voltage sags. The topology consists of two conventional three-phase bridge inverters arranged to require just a single DC source. This inverter is also characterized by a voltage multilevel operation, providing the full advantages of multilevel converters without the need for level balancing. Associated with this AC motor driver, a control system based on a field-oriented controller with a vector voltage modulator that will enable voltage sag ride-through capability is proposed. The proposed control system does not require any changes in the occurrence of voltage sags. To verify the characteristics of the proposed drive and control system, simulation tests are provided. Simulation results confirm the voltage sag resilient capability of the proposed multilevel converter.
Vitor Fernão Pires; Joaquim Monteiro; José Fernando Silva. Dual 3-Phase Bridge Multilevel Inverters for AC Drives with Voltage Sag Ride-through Capability. Energies 2019, 12, 2324 .
AMA StyleVitor Fernão Pires, Joaquim Monteiro, José Fernando Silva. Dual 3-Phase Bridge Multilevel Inverters for AC Drives with Voltage Sag Ride-through Capability. Energies. 2019; 12 (12):2324.
Chicago/Turabian StyleVitor Fernão Pires; Joaquim Monteiro; José Fernando Silva. 2019. "Dual 3-Phase Bridge Multilevel Inverters for AC Drives with Voltage Sag Ride-through Capability." Energies 12, no. 12: 2324.
The boost feature that characterizes Z-source and quasi-Z-source converters is usually achieved by means of a proper insertion of short-circuit states in the full DC-link. In this work, a novel pulse width modulation carrier-based strategy for a three-phase, three-level T-type, quasi-Z-source inverter is introduced, based on the addition of alternate short-circuits in the two halves of the DC-link bus. This technique achieves better performance, less electromagnetic interference, and lower harmonic distortion of the output line-to-line voltage compared to the traditional methods based on the full DC-link shoot-through. At the same time, generating the switching states is to easy implement. The proposed strategy permits the use of electronic devices with lower blocking voltage capability, thus improving converter reliability, size, and cost. The new method may be implemented in another multilevel inverter with an impedance-source network as well. A comprehensive simulation study is performed in order to validate the adopted method, with different inverter input voltages, which is taken as representative of a photovoltaic array. Comparisons are conducted with conventional strategy insertions using the same topology in order to show the improvements achieved.
Fermín Barrero-González; Carlos Roncero-Clemente; María Isabel Milanés-Montero; Eva González-Romera; Enrique Romero-Cadaval; Oleksandr Husev; V. Fernão Pires. Improvements on the Carrier-Based Control Method for a Three-Level T-Type, Quasi-Impedance-Source Inverter. Electronics 2019, 8, 677 .
AMA StyleFermín Barrero-González, Carlos Roncero-Clemente, María Isabel Milanés-Montero, Eva González-Romera, Enrique Romero-Cadaval, Oleksandr Husev, V. Fernão Pires. Improvements on the Carrier-Based Control Method for a Three-Level T-Type, Quasi-Impedance-Source Inverter. Electronics. 2019; 8 (6):677.
Chicago/Turabian StyleFermín Barrero-González; Carlos Roncero-Clemente; María Isabel Milanés-Montero; Eva González-Romera; Enrique Romero-Cadaval; Oleksandr Husev; V. Fernão Pires. 2019. "Improvements on the Carrier-Based Control Method for a Three-Level T-Type, Quasi-Impedance-Source Inverter." Electronics 8, no. 6: 677.
In this paper it is proposed a Static Synchronous Compensator (STATCOM) in which it is used a modular structure with conventional three-phase voltage source inverters to obtain multilevel operation. The inverters are connected to the transformer in an open-end winding configuration and with three independent DC links. In this structure, the inverters will be connected in a cascade configuration. Besides the multilevel operation, the system is also characterized by needing lower blocking voltages for switch ratings, since the proposed STATCOM can apply the double of the DC capacitor voltage to the transformer windings. The development of the control system for the proposed topology is also presented. The operation of the proposed topology and the performance of the developed control system will be tested through several simulation and experimental tests.
Vitor Fernao Pires; Armando Cordeiro; Daniel Foito; J. Fernando Silva. A STATCOM Based on a Three-Phase, Triple Inverter Modular Topology for Multilevel Operation. IEEE Transactions on Power Delivery 2019, 34, 1988 -1997.
AMA StyleVitor Fernao Pires, Armando Cordeiro, Daniel Foito, J. Fernando Silva. A STATCOM Based on a Three-Phase, Triple Inverter Modular Topology for Multilevel Operation. IEEE Transactions on Power Delivery. 2019; 34 (5):1988-1997.
Chicago/Turabian StyleVitor Fernao Pires; Armando Cordeiro; Daniel Foito; J. Fernando Silva. 2019. "A STATCOM Based on a Three-Phase, Triple Inverter Modular Topology for Multilevel Operation." IEEE Transactions on Power Delivery 34, no. 5: 1988-1997.
Most fuel cell electric vehicles (FCEV) require wide voltage-gain DC DC converters to increase and equalize the relatively low voltage of fuel cell stacks with DC link bus or energy storage devices (ESD), such as supercapacitors or batteries. This paper proposes two new non-isolated DC-DC converters suitable for such applications, which can be extended to other electric vehicles as well. The proposed converters combine the main characteristics of both quadratic Boost and Ćuk converters, offering high step up voltage and control simplicity using only one ground referenced active power switch. Additionally, the proposed topologies present reduced voltage stress across the active power switch when compared to other Boost converters. Considerations about the design of the proposed converters will also be presented. Experimental results obtained using a laboratory prototype validate the effectiveness and feasibility of the proposed topologies and its suitability for fuel cell electric vehicles.
Vitor Fernao Pires; Armando Cordeiro; Daniel Foito; Jose Fernando Silva. High Step-Up DC–DC Converter for Fuel Cell Vehicles Based on Merged Quadratic Boost–Ćuk. IEEE Transactions on Vehicular Technology 2019, 68, 7521 -7530.
AMA StyleVitor Fernao Pires, Armando Cordeiro, Daniel Foito, Jose Fernando Silva. High Step-Up DC–DC Converter for Fuel Cell Vehicles Based on Merged Quadratic Boost–Ćuk. IEEE Transactions on Vehicular Technology. 2019; 68 (8):7521-7530.
Chicago/Turabian StyleVitor Fernao Pires; Armando Cordeiro; Daniel Foito; Jose Fernando Silva. 2019. "High Step-Up DC–DC Converter for Fuel Cell Vehicles Based on Merged Quadratic Boost–Ćuk." IEEE Transactions on Vehicular Technology 68, no. 8: 7521-7530.
The integration of energy storage systems in power distribution networks allows to obtain several benefits, such as, the minimization of energy losses, the improvement of voltage profile and the reduction of the energy costs. However, due to the high cost of these energy storage systems, this integration must be carefully applied. Thus, this work proposes the integration of energy storage systems based on a multiobjective optimization. The type of storage systems that is considered are the batteries. These systems require electronic power converters as an interface between the batteries and the grid. Thus, this work uses those converters to supply an ancillary service, more specifically, reactive power compensation. In this way, besides the peak shaving, the optimization approach will also consider the reactive-power compensation, allowing to improve the capital investment return of these systems. The reactive power compensation considers the maximum active power of the converter, to minimize the cost of the system. In consequence, when the energy storage system is at its maximum discharge mode, the reactive power compensation function will be inhibited. Since the multi-objective optimization generates a Pareto-optimal set with a large number of solutions, an approach to support the choice of the solution is also proposed. This approach considers a new post-Pareto analysis, which is based on the sum of the ranking differences. To demonstrate the applicability of the proposed approach, a case study using the 94-bus real test feeder is presented. Three scenarios tests are also presented for the post-pareto optimality analysis, each considering different weights for the objective functions. The results show that even for a specific case where the weights are assigned for each of the objective functions, more than one solution is obtained.
V. Fernão Pires; A. Vieira Pombo; João Miguel Lourenço. Multi-objective optimization with post-pareto optimality analysis for the integration of storage systems with reactive-power compensation in distribution networks. Journal of Energy Storage 2019, 24, 100769 .
AMA StyleV. Fernão Pires, A. Vieira Pombo, João Miguel Lourenço. Multi-objective optimization with post-pareto optimality analysis for the integration of storage systems with reactive-power compensation in distribution networks. Journal of Energy Storage. 2019; 24 ():100769.
Chicago/Turabian StyleV. Fernão Pires; A. Vieira Pombo; João Miguel Lourenço. 2019. "Multi-objective optimization with post-pareto optimality analysis for the integration of storage systems with reactive-power compensation in distribution networks." Journal of Energy Storage 24, no. : 100769.
The proliferation of residential photovoltaic (PV) prosumers leads to detrimental impacts on the low-voltage (LV) distribution network operation such as reverse power flow, voltage fluctuations and voltage imbalances. This is due to the fact that the strategies for the PV inverters are usually designed to obtain the maximum energy from the panels. The most recent approach to these issues involves new inverter-based solutions. This paper proposes a novel comprehensive control strategy for the power electronic converters associated with PV installations to improve the operational performance of a four-wire LV distribution network. The objectives are to try to balance the currents demanded by consumers and to compensate the reactive power demanded by them at the expense of the remaining converters’ capacity. The strategy is implemented in each consumer installation, constituting a decentralized or distributed control and allowing its practical implementation based on local measurements. The algorithms were tested, in a yearly simulation horizon, on a typical Portuguese LV network to verify the impact of the high integration of the renewable energy sources in the network and the effectiveness and applicability of the proposed approach.
Fermín Barrero-González; Victor Fernão Pires; José L. Sousa; João F. Martins; María Isabel Milanés-Montero; Eva González-Romera; Enrique Romero-Cadaval. Photovoltaic Power Converter Management in Unbalanced Low Voltage Networks with Ancillary Services Support. Energies 2019, 12, 972 .
AMA StyleFermín Barrero-González, Victor Fernão Pires, José L. Sousa, João F. Martins, María Isabel Milanés-Montero, Eva González-Romera, Enrique Romero-Cadaval. Photovoltaic Power Converter Management in Unbalanced Low Voltage Networks with Ancillary Services Support. Energies. 2019; 12 (6):972.
Chicago/Turabian StyleFermín Barrero-González; Victor Fernão Pires; José L. Sousa; João F. Martins; María Isabel Milanés-Montero; Eva González-Romera; Enrique Romero-Cadaval. 2019. "Photovoltaic Power Converter Management in Unbalanced Low Voltage Networks with Ancillary Services Support." Energies 12, no. 6: 972.
Voltage source inverters (VSIs) are power converters that are considered essential in grid connected photovoltaic (PV) generators. There are several types of topologies for these converters. However, from the point of view of high-quality AC output voltage, multilevel inverters are considered the most adequate. Under this context, this study proposes a new structure for the three-phase DC−AC conversion stage for a grid-connected PV system. It consists of two four-leg two-level voltage source inverters that are connected to two PV generators. These inverters are associated with two Scott transformers. The secondary windings of the transformer are connected in a way that allows a series connection. Due to this, a multilevel operation will be achieved. The performance of the proposed power conditioning system will be verified through simulation and experimental results.
Vitor Fernão Pires; Daniel Foito; Armando Cordeiro. PV power conditioning system using a three‐phase multilevel pulse width modulation inverter employing cascaded Scott transformers. IET Power Electronics 2019, 12, 102 -111.
AMA StyleVitor Fernão Pires, Daniel Foito, Armando Cordeiro. PV power conditioning system using a three‐phase multilevel pulse width modulation inverter employing cascaded Scott transformers. IET Power Electronics. 2019; 12 (1):102-111.
Chicago/Turabian StyleVitor Fernão Pires; Daniel Foito; Armando Cordeiro. 2019. "PV power conditioning system using a three‐phase multilevel pulse width modulation inverter employing cascaded Scott transformers." IET Power Electronics 12, no. 1: 102-111.
Solid State Transformers (SST) may become, in the near future, key technological enablers for decentralized energy supply systems. They have the potential to unleash new technologies and operation strategies of microgrids and prosumers to move faster towards a low carbon-based economy. This work proposes a paradigm change in the hierarchically and distributed operated power systems where SSTs are used to asynchronously connect the many small low voltage (LV) distribution networks, such as clusters of prosumers or LV microgrids, to the bulk power system. The need for asynchronously coupled microgrids requires a design that allows the LV system to operate independently from the bulk grid and to rely on its own control systems. The purpose of this new approach is to achieve immune and resilient by design configurations that allow maximizing the integration of Local Renewable Energy Resources (L-RES). The paper analyses from the stability point of view, through simplified numerical simulations, the way in which SST-interconnected microgrids can become immune to disturbances that occur in the bulk power system and how sudden changes in the microgrid can damp out at the Point of Common Coupling (PCC), thus achieving better reliability and predictability in both systems and enabling strong and healthy distributed energy storage systems (DESSs). Moreover, it is shown that in a fully inverter-based microgrid there is no need for mechanical or synthetic inertia to stabilize the microgrid during power unbalances. This happens because the electrostatic energy stored in the capacitors connected behind the SST inverter can be used for a brief time interval, until automation is activated to address the power unbalance for a longer term.
Mihai Sanduleac; João F. Martins; Irina Ciornei; Mihaela Albu; Lucian Toma; Vitor Fernão Pires; Lenos Hadjidemetriou; Rooktabir Sauba. Resilient and Immune by Design Microgrids Using Solid State Transformers. Energies 2018, 11, 3377 .
AMA StyleMihai Sanduleac, João F. Martins, Irina Ciornei, Mihaela Albu, Lucian Toma, Vitor Fernão Pires, Lenos Hadjidemetriou, Rooktabir Sauba. Resilient and Immune by Design Microgrids Using Solid State Transformers. Energies. 2018; 11 (12):3377.
Chicago/Turabian StyleMihai Sanduleac; João F. Martins; Irina Ciornei; Mihaela Albu; Lucian Toma; Vitor Fernão Pires; Lenos Hadjidemetriou; Rooktabir Sauba. 2018. "Resilient and Immune by Design Microgrids Using Solid State Transformers." Energies 11, no. 12: 3377.
In many photovoltaic (PV) power plants, the PV modules are installed in trackers. In these systems, the PV modules are fixed in a mobile structure to always maintain a perpendicular position to the brightest point in the sky, obtaining in this way the maximum power from the sun, during the all day. Nevertheless, these systems are subject to problems that reduce their efficiency. Thus, visual inspection or complex methods can be used to detect this problem. However, these systems normally result in delays or are expensive. To overcome these problems, this paper proposes a new method for that detection. This, method is based on the pattern recognition analysis. Thus, through the analysis of the images of the several solar panels, the PV module that presents a problem in the tracker will be detected. The orientation of the PV modules is determined using the centroid of the PV cells after applying an image pre‐processing stage. The angle is calculated using the statistical moments or by the slope of the line joining two centroids of the PV cells that are located at the vertices of the PV module. Several test cases are presented to verify the efficiency of the proposed approach.
Tito G. Amaral; V. Fernão Pires. Fault detection in trackers for PV systems based on a pattern recognition approach. International Transactions on Electrical Energy Systems 2018, 29, e2771 .
AMA StyleTito G. Amaral, V. Fernão Pires. Fault detection in trackers for PV systems based on a pattern recognition approach. International Transactions on Electrical Energy Systems. 2018; 29 (3):e2771.
Chicago/Turabian StyleTito G. Amaral; V. Fernão Pires. 2018. "Fault detection in trackers for PV systems based on a pattern recognition approach." International Transactions on Electrical Energy Systems 29, no. 3: e2771.
V. Fernão Pires; A. Cordeiro; D. Foito; J. Fernando Silva. Corrigendum to “Three-phase multilevel inverter for grid-connected distributed photovoltaic systems based in three three-phase two-level inverters” [Solar Energy 174 (2018) 1026–1034]. Solar Energy 2018, 185, 525 .
AMA StyleV. Fernão Pires, A. Cordeiro, D. Foito, J. Fernando Silva. Corrigendum to “Three-phase multilevel inverter for grid-connected distributed photovoltaic systems based in three three-phase two-level inverters” [Solar Energy 174 (2018) 1026–1034]. Solar Energy. 2018; 185 ():525.
Chicago/Turabian StyleV. Fernão Pires; A. Cordeiro; D. Foito; J. Fernando Silva. 2018. "Corrigendum to “Three-phase multilevel inverter for grid-connected distributed photovoltaic systems based in three three-phase two-level inverters” [Solar Energy 174 (2018) 1026–1034]." Solar Energy 185, no. : 525.
A multilevel three-phase voltage source inverter (VSI) for distributed grid-connected photovoltaic system is proposed in this paper. This multilevel inverter is based on a new topology using three three-phase two-level VSIs (T3VSI) with isolation transformer. The photovoltaic panels are connected at the DC side of each three-phase VSI. The three-phase VSIs AC sides are connected to the three-phase isolation transformer with primary open-end windings, ensuring multilevel operation. The T3VSI can be modulated using existing multilevel Pulse Width Modulation (PWM) schemes. A control system designed to ensure the transfer of the energy generated by the PV generators to the grid is also presented, together with a Phase Disposition PWM (PDPWM) adapted for the multilevel T3VSI. Tests of the grid-connected PV multilevel T3VSI will be shown through simulation and experimental results. Several results obtained from experiments confirm the expected characteristics of the multilevel T3VSI photovoltaic system.
V. Fernão Pires; Armando Cordeiro; D. Foito; J. Fernando Silva. Three-phase multilevel inverter for grid-connected distributed photovoltaic systems based in three three-phase two-level inverters. Solar Energy 2018, 174, 1026 -1034.
AMA StyleV. Fernão Pires, Armando Cordeiro, D. Foito, J. Fernando Silva. Three-phase multilevel inverter for grid-connected distributed photovoltaic systems based in three three-phase two-level inverters. Solar Energy. 2018; 174 ():1026-1034.
Chicago/Turabian StyleV. Fernão Pires; Armando Cordeiro; D. Foito; J. Fernando Silva. 2018. "Three-phase multilevel inverter for grid-connected distributed photovoltaic systems based in three three-phase two-level inverters." Solar Energy 174, no. : 1026-1034.
Many applications require a DC bus supporting connections to several renewable energy sources, storage systems and loads. However, due to the intermittent nature of renewable energy sources and load variations it is essential to stabilize the voltage of the DC bus. Usually a battery is used to support the DC bus voltage, but their continuous charge and discharge cycling will affect his lifetime. Thus, the use of a storage system based in supercapacitors provides an interesting alternative to stabilize the DC power grid. In this context, this work presents a study of a storage system based in supercapacitors combined with a bidirectional quadratic DC-DC converter to support the DC bus. A full design of the controllers for the quadratic converter is also presented. The behaviour of the system will be tested through several simulation results.
Vitor Fernao Pires; Armando Cordeiro; Daniel Foito; J. Fernando Silva. Control of Bidirectional Quadratic DC-DC Converters for Storage Support of DC Power Grids. 2018 7th International Conference on Renewable Energy Research and Applications (ICRERA) 2018, 227 -232.
AMA StyleVitor Fernao Pires, Armando Cordeiro, Daniel Foito, J. Fernando Silva. Control of Bidirectional Quadratic DC-DC Converters for Storage Support of DC Power Grids. 2018 7th International Conference on Renewable Energy Research and Applications (ICRERA). 2018; ():227-232.
Chicago/Turabian StyleVitor Fernao Pires; Armando Cordeiro; Daniel Foito; J. Fernando Silva. 2018. "Control of Bidirectional Quadratic DC-DC Converters for Storage Support of DC Power Grids." 2018 7th International Conference on Renewable Energy Research and Applications (ICRERA) , no. : 227-232.
This paper presents a quasi-Z-source (qZS) converter that allows to supply multilevel voltages for the switched reluctance machine (SRM) drive. The use of qZS converter in SRM drives allows obtaining better high speed operation characteristics since higher voltages can be achieved. The proposed drive uses a qZS converter but designed in order to be possible to apply, to the SRM, different voltage levels on the magnetizing and demagnetizing stages. The presented converter also allows to regulate the output voltages and the difference between the voltage levels. Thus, it is possible to improve the efficiency of the drive, by reducing the switching frequency, as well as having better characteristics for high-speed operation. Different configurations of the converter are presented and the modulator associated to the SRM drive is described. In order to verify the features of the proposed system several results are also presented and discussed.
Vitor Fernao Pires; A. J. Pires; João Martins; Chen Hao. A Quasi-Z-Source Converter to Feed a Switched Reluctance Drive with Multilevel Voltages. IECON 2018 - 44th Annual Conference of the IEEE Industrial Electronics Society 2018, 3706 -3711.
AMA StyleVitor Fernao Pires, A. J. Pires, João Martins, Chen Hao. A Quasi-Z-Source Converter to Feed a Switched Reluctance Drive with Multilevel Voltages. IECON 2018 - 44th Annual Conference of the IEEE Industrial Electronics Society. 2018; ():3706-3711.
Chicago/Turabian StyleVitor Fernao Pires; A. J. Pires; João Martins; Chen Hao. 2018. "A Quasi-Z-Source Converter to Feed a Switched Reluctance Drive with Multilevel Voltages." IECON 2018 - 44th Annual Conference of the IEEE Industrial Electronics Society , no. : 3706-3711.