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Showing papers by "V. Fernao Pires published in 2018"


Journal ArticleDOI
TL;DR: 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 adapted for the multilevel T3VSI.

44 citations


Proceedings ArticleDOI
01 Oct 2018
TL;DR: A new multilevel topology is presented based on the T-type structure and characterized by a reduced number of power semiconductors resulting in a low cost, size and weight system for SRM drives.
Abstract: Multilevel power converters have been used in SRM drives to improve high speed operating characteristics and reduce switching frequency. Several topologies have been proposed to these drives but it requires an increased number of switches. In this paper it is presented a new multilevel topology for the SRM drives. This topology is based on the T-type structure and characterized by a reduced number of power semiconductors resulting in a low cost, size and weight system. With this topology it is possible to accelerate the magnetization and demagnetization process as well as the efficiency of the system through the reduction of the switching frequency at low speed operation. The characteristics and performance of the proposed topology will be verified through several numerical tests.

17 citations


Journal ArticleDOI
TL;DR: The obtained results allow the conclusion that the PV system harmonic compensation capability is able to attenuate the harmonics, therefore improving the voltage profile, and reducing the power losses and voltage drop on the LV distribution network.

17 citations


Proceedings ArticleDOI
01 Oct 2018
TL;DR: This paper presents a new DC-DC power converter topology with Buck- Boost operation and extended output voltage using a single power semiconductor that operates with reduced voltage stress in thePower semiconductor.
Abstract: DC-DC Buck-Boost power converters are extensively used in several applications, from renewable energy sources to most industrial equipment. Nevertheless, to achieve proper integration of certain devices it is often necessary to provide converters with extended output voltage. This paper presents a new DC-DC power converter topology with Buck- Boost operation and extended output voltage using a single power semiconductor. Additionally, this converter operates with reduced voltage stress in the power semiconductor. The performance of this power converter will be proven trough simulations and experimental tests.

13 citations


Journal ArticleDOI
TL;DR: This paper proposes a multiobjective optimization approach for the location and sizing of storage systems in distribution networks, where the objective functions are in conflict and increasing the number of systems leads to a reduction in the peak power and losses but also will increase the investment cost.
Abstract: The use of storage systems in distribution networks allows smoothing the load diagram. In fact, the cost of energy is different along the day and companies can be encouraged to use these systems, since the extra energy required to charge the storage system can be obtained in periods where the cost of the energy is lower and used in periods when the energy cost is higher. Storage systems also allow reducing losses of the lines and improving voltage profile. However, in distribution networks there are benefits in using distributed storage instead of centralized storage. Under this context, this paper proposes a multiobjective optimization approach for the location and sizing of storage systems. In this problem, the objective functions are in conflict. Increasing the number of storage systems leads to a reduction in the peak power and losses, but also will increase the investment cost. This approach allows obtaining solutions of different trade-offs with respect to the two objectives. An IEEE 69 buses and a real 94 buses test feeders are used to demonstrate the effectiveness of the proposed approach.

10 citations


Proceedings ArticleDOI
10 Apr 2018
TL;DR: This study will show the impact of the 3L-Active NPC (3L-ANPC) to the qZS inverters on the efficiency of the system as well as on the distribution of the switching losses.
Abstract: Quasi-Z-source (qZS) inverters have been found very suitable in boost operation applications. As a result, studies have focused on the three-level neutral-point-clamped (3L-NPC) qZS inverters. However, this topology has a shortcoming of loss distribution among the switches. Focus in this article is on the application of the 3L-Active NPC (3L-ANPC) to the qZS inverters. Our study will show the impact of this topology on the efficiency of the system as well as on the distribution of the switching losses. A shoot-through sinusoidal pulse with modulation adapted to the 3L-ANPC was used. A modified modulation was also implemented and tested. Several simulation tests were performed to analyze the adopted topology and modulation strategies.

5 citations


Journal ArticleDOI
TL;DR: In this paper, the authors presented a wireless energy transfer system operating at the frequency values of kHz order: modeling, simulation, and comparison with prototype measurement results, which showed an error of roughly 8.7%.
Abstract: This paper presents a wireless energy transfer system operating at the frequency values of kHz order: modeling, simulation, and comparison with prototype measurement results. Wireless energy transfer system model using finite element method was carried out to simulate the electric field and the magnetic flux density for different air gap sizes between the transmitter and the receiver coils. Results are presented and compared with the electromagnetic emission measurements radiated by the wireless energy transfer system prototype. The electric field comparison between the simulated and the prototype measurement values shows an error of roughly 8.7%. In the recent years, the interest in the wireless energy transfer technology, especially for electric vehicles batteries charging, is rapidly increasing. As a result of the increasing application of this technology in the industrial and consumer electronic products, more concerns are raised about the electromagnetic compatibility, since the wireless ener...

5 citations


Proceedings ArticleDOI
01 Oct 2018
TL;DR: A new fault detection and diagnosis method for transistor faults in a SRM drive based on symmetry indexes that are created from the analysis of the currents patterns, presenting immunity to different mechanical conditions is presented.
Abstract: To reduce the negative impacts of power converters on a machine such as switched reluctance motor (SRM) a fast and accurate fault detection method is required. Several fault types could occur in SRM drives, such as, open and short-circuit transistor faults. Thus, this paper presents a new fault detection and diagnosis method for transistor faults in a SRM drive. The method is based on symmetry indexes that are created from the analysis of the currents patterns. The proposed approach results in a fast and robust method, presenting immunity to different mechanical conditions. The characteristics of the proposed method will be verified through several simulation tests.

4 citations


Proceedings ArticleDOI
01 Oct 2018
TL;DR: 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.
Abstract: 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.

3 citations


Proceedings ArticleDOI
01 Oct 2018
TL;DR: In this paper, a voltage modulator for a dual inverter with a floating bridge is proposed to regulate and stabilize the voltage capacitor of the floating bridge, which can provide an asymmetric operation of the DC voltages.
Abstract: This paper presents a new control strategy based on a voltage modulator for a dual inverter with a floating bridge. This converter is characterized by a multilevel operation with two conventional two-level voltage source inverters and a single DC voltage source. The proposed control and modulation scheme allows a fast and robust operation of the inverter. The voltage modulator will allow the regulation and stability of the voltage capacitor of the floating bridge. It was also developed to provide an asymmetrical operation of the DC voltages (single DC source and capacitor). Due to this, high output voltage levels will be ensured. Several simulation results will be provided to show the characteristics of the proposed system.

2 citations


Proceedings ArticleDOI
20 Jun 2018
TL;DR: An EV charging system supported by RES and a storage system (supercapacitors and batteries) and the management of the storage systems, as well as an overall controller to stabilize the DC voltage bus are presented.
Abstract: It is predicted to the near future that electric vehicle (EV) charging systems will have an important impact on the electric infrastructures Thus, in order to contribute to a sustainable world, the use of renewable energy sources (RES) will play an important role to generate the required energy to the EVs However, in order to optimize the global electrical efficiency, the RES should be placed as near as possible to the EVs charging systems On the other hand, to provide stability to the system, energy storage systems, such as batteries and supercapacitors should also be considered Under this context, this paper presents an EV charging system supported by RES and a storage system (supercapacitors and batteries) It will be presented the management of the storage systems, as well, an overall controller to stabilize the DC voltage bus Several modes of the charging system operation will be presented It also be presented results of the overall system showing the effectiveness of the proposed algorithms