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Model predictive control (MPC) has been widely applied to ac electric drives over the last decade. Despite the proposed solutions, researchers are still seeking to find more effective solutions for weighting factor (WF) design, parameter dependency, current/torque harmonics, variable switching frequency, and computational complexity. This article presents a comprehensive review of the WF design techniques for finite control set MPC strategies for ac electric drives. First, the article introduces the conventional MPC techniques for electric drives over permanent magnet synchronous motors. Second, WF design methods are discussed under two main headings: WF selection and WF elimination methods. Third, the ongoing challenges and future trends are addressed by considering the current literature. Based on this review, it is obvious that each WF design method still has problems that await more effective solutions. Finally, this article reviews various WF design methods for ac electric drives, reveals the advantages and disadvantages of existing methods in terms of control performance, flexibility, design complexity, and computational complexity, and highlights future trends.

This article presents a predictive control strategy to control a photovoltaic plant based on bifacial photovoltaic (BPV) panels connected to the electrical grid through a three-phase neutral point clamped (NPC) power converter. Electricity generation plants based on nonconventional renewable energies are affected by the availability of the natural resource and grid changes. To achieve optimal use of natural resources and equipment, BPV cells must operate at the maximum power point and the currents injected into a grid must be in phase with the voltages. Due to the high number of states, one important drawback of conventional predictive control in the NPC converter is its computational burden. The proposed controller avoids the use of a cost function and can achieve the same control objectives with only 20% of the computational cost of the conventional strategy. To achieve this reduction the proposed strategy exploits the operating area of the converter, separating the possible voltages in hexagons, which results in a shape like a honeycomb. Simulation and experimental results show the feasibility of the proposed method in different operating conditions.

This article deals with the investigation of dc plasma discharge of Ar–CO gas mixture in which the relative electron density and absolute temperature were measured. Relative electron density and absolute temperature were obtained for the mixture at discharge powers between 200 and 12 000 mW, and pressures between 0.1 and 0.5 mbar employing the radiative collisional model for several Ar–CO mixtures. Behavior of the electron temperature and relative number density are discussed. The absolute number density of the 1s5 was found to be higher than that of the 1s3 level.

The main objective of this letter is to propose new circuits for multisource multilevel inverters that require fewer power switches. To address the limitations of existing multilevel inverters, which require a high number of power switches and dc voltage sources to produce a large number of voltage levels, the first designed circuit uses fewer switches, and the second circuit uses lower dc sources to generate a high number of voltage levels. Based on a comparison with other reported inverters, the new circuits produce a large number of levels with reduced power switches and dc voltage sources. The power losses and efficiency of the second proposed circuit are evaluated by software simulation and compared with other inverters. The performance of the proposed circuit is tested and evaluated using hardware results for different operation conditions.

The cascaded multilevel inverters (MLIs) are suitable topologies when a high number of voltage levels are needed. Nonetheless, cascaded topologies possess the main drawback of a high number of power switches and gate drivers that make sophisticated control, reducing efficiency, and increasing cost. This article proposes a new fundamental switched-diode topology that is capable of generating five positive-voltage levels with only three power switches, three power diodes, and three dc voltage sources. Based on a combination of the $n$ number of new fundamental topology, two cascaded topologies are proposed, which increases the number of voltage levels and decreases the number of power switches and voltage stress. The proposed cascaded topologies can operate in asymmetric dc sources, so different dc voltage source magnitudes are submitted to minimize the number of components. The main advantages of the proposed cascaded topologies are reducing the number of power switches, and gate drivers with reasonable dc voltage sources count in comparison with other state-of-the-art cascaded topologies. Furthermore, the proposed topologies reduce the cost in comparison with other recent MLI topologies. The power loss analysis and the recommended application for the proposed topologies are discussed. The simulation and experimental works are presented to verify the operation correctness of the proposed topologies.

Coupled-inductor buck-boost dc-dc switching converter has emerged as an alternative to manage power in several hybrid system architectures. This is due to features such as a noninverting voltage step-up and step-down characteristic, high efficiency, wide bandwidth, and the possibility to regulate its input or output currents as has been reported in previous works. All of them are based on a small-signal linearized model around an operating point. In this article, a model predictive control strategy is proposed to increase the operation point domain. The proposal consists in the use of the mathematical model of the system in discrete time to obtain the optimal switching state to be applied in the converter based on a cost function optimization, which simultaneously improves the current tracking and reduces the converter power losses. Experimental results validate the proposal demonstrating that this is a good alternative for the control of this kind of power converters.

ABSTRACTSeveral new high-performance power semiconductors have appeared during the last decade, being the silicon carbide (SiC) MOSFETs the most promising to be commercialised as an alternative of Si IGBT. This paper presents the performance analysis of a controller for a full H-bridge based on SiCMOSFET technology used for high frequency and medium voltage applications. The switching performance of a modular H-bridge is analysed and the efficiency/losses and temperature dissipation are experimentally measured in order to help engineers to design and develop circuits using this power semiconductor. A comparison between SiCMOSFET and Si MOSFET is also presented.

This paper proposes a generalized commutation strategy suitable for matrix-based isolated ac/ac conversion stages in solid-state transformers for use whenever there is nonnegligible leakage inductance in the isolation transformer. The standard 4-step commutation used in matrix converters can no longer be applied when transformer leakage inductance is present, as overrated switching devices or dissipative snubbers would be necessary, reducing the attractiveness of the topologies that include matrix-based isolated ac/ac stages. A case study of a single-phase ac/ac converter has been investigated in detail to demonstrate the application of the proposed commutation method to a topology that has recently been identified as the potential building block for future multimodular ac/ac converters for grid applications. The proposed leakage-inductance-tolerant commutation strategy is based on the definition of a current decoupling phase in the commutation sequence and only needs suitable timing of the commutation steps, without high bandwidth voltage or current measurements. Matching simulations and experimental results from a 3-kW laboratory scale prototype are presented to support the effectiveness of the proposed strategy.

Finite control set model predictive control can be applied to a power converter if there is an accurate existing model of the converter. The best results will be achieved if and only if the parameters and variables that make up the system are properly estimated. If this is not the case, the predictions made using these strategies may be erroneous and cause problems, such as steady-state error with respect to the assigned desired references. This paper presents a predictive control strategy with integral action that compensates for the differences between the estimated model and the inverter with the objective of achieving a zero steady-state error without requiring external loops or state observers. The proposed strategy is tested on a single-phase Z-source inverter so as to evaluate the error in both the ac and dc controlled variables with respect to their references to their cosigns. The experimental results confirm that the proposed strategy achieves a zero error in the steady state while maintaining the fast dynamic response of the classic predictive control.

Brushless doubly fed induction machines (BDFIMs) feature some important advantages, such as high reliability and low maintenance cost, over alternative solutions for brushless machine applications. This paper proposes a modulated model predictive control (MPC) algorithm for BDFIMs, which achieves a fixed switching frequency and superior system performance. An improvement of power quality is shown in this paper when compared to the conventional finite-control set-MPC. This paper examines the design and implementation of the modulation technique as well as presenting the simulation and experimental results to verify the technique’s operation.

The features and potential of predictive control techniques in power electronics applications have been demonstrated and widely studied during the last 15 years. The most remarkable advantages are the intuitive control scheme, great flexibility to cover a variety of degrees of freedom, and the straight-forward incorporation of nonlinear variables and constraints. Although this proposal with very attractive characteristics dates back to the 1970s, the experimental validation has only been possible recently, thanks to the development of modern digital controllers due to the relatively high computational burden associated with this method. The great effort of the researchers enabled a large number of publications in journals and dedicated conferences that has positioned this strategy as a viable alternative to the classical controllers. Thus, implementations based on this approach in proposals such as variable-speed drives, current, voltage, and power regulation, renewable energy generation systems, microgrids, energy storage, or electric vehicles (EVs) can be found in the literature. It is expected that the pace of developments with the predictive control keeps the current trend, because of the great opportunities in the research and industrial fields.

The Predator Launch and Recovery Element (LRE) at Balad Air Base, Iraq, was set to receive an MQ-1 Predator for a routine landing. They received word from the Predator Operations [...]

A novel predictive rotor current control scheme for a doubly fed induction generator (DFIG) is implemented to perform the DFIG grid synchronization with a fast dynamic response. With this control strategy applied to an experimental setup, the rotor currents swiftly follow the necessary reference for grid synchronization in the range ±30% of the generator rated shaft speed. The DFIG and converter discrete models are used to predict the behavior of the rotor currents. By minimizing the error between the references and the predictive rotor currents for each of the valid states of the converter, the best-suited switching state is selected and applied at the next sampling time. To validate the feasibility of implementing this approach, simulations and experiments were carried out for various shaft speed profiles.

A new power conversion system is explored in this paper aiming wind turbines rated at the megawatt level. The proposed configuration consists of a medium-voltage, permanent magnet synchronous generator connected to a low-cost three-phase diode bridge rectifier, a dc–dc four-level boost converter as the intermediate stage, and a four-level diode-clamped inverter on the grid-side. The dc-link capacitor voltages are balanced by the boost converter, and thus the control complexity for the grid-tied inverter is greatly simplified. To control the boost converter and grid-tied inverter, a simple method based on a two-step model predictive strategy is presented. In the first part of this paper, the continuous- and discrete-time modeling of the proposed power conversion system is analyzed. The control objectives such as maximum power point tracking, dc-link capacitor voltages balancing, regulation of net dc-bus voltage, reactive power generation, lower switching frequency operation, and common-mode voltage minimization are considered in the design of controller.

In this paper, a new medium-voltage power conversion system consisting of a four-level boost converter and four-level diode-clamped inverter is proposed for permanent magnet synchronous generator-based megawatt-level wind turbines. To achieve a simple and optimal control performance, a simplified two-step model predictive strategy is proposed. The high-power wind turbine requirements, which include maximum energy harvesting, balancing of dc-link capacitor voltages, net dc-bus voltage control, regulation of grid-reactive power, and the minimization of both switching frequency and common-mode voltage are expressed as cost functions. The best switching states are chosen and applied to the power converters during each sampling interval based on the minimization of cost functions. The feasibility of the proposed configuration and control scheme are verified through MATLAB/Simulink tests on a high power (5 MVA/4160 V/694 A) system and dSPACE experiments on a low power (3.6 kVA/208 V/10 A) prototype.

Abstract Ubinas volcano has had 23 degassing and ashfall episodes since A.D. 1550, making it the historically most active volcano in southern Peru. Based on fieldwork, on interpretation of aerial photographs and satellite images, and on radiometric ages, the eruptive history of Ubinas is divided into two major periods. Ubinas I (Middle Pleistocene >376 ka) is characterized by lava flow activity that formed the lower part of the edifice. This edifice collapsed and resulted in a debris-avalanche deposit distributed as far as 12 km downstream the Rio Ubinas. Non-welded ignimbrites were erupted subsequently and ponded to a thickness of 150 m as far as 7 km south of the summit. These eruptions probably left a small collapse caldera on the summit of Ubinas I. A 100-m-thick sequence of ash-and-pumice flow deposits followed, filling paleo-valleys 6 km from the summit. Ubinas II, 376 ky to present comprises several stages. The summit cone was built by andesite and dacite flows between 376 and 142 ky. A series of domes grew on the southern flank and the largest one was dated at 250 ky; block-and-ash flow deposits from these domes filled the upper Rio Ubinas valley 10 km to the south. The summit caldera was formed between 25 and 9.7 ky. Ash-flow deposits and two Plinian deposits reflect explosive eruptions of more differentiated magmas. A debris-avalanche deposit (about 1.2 km3) formed hummocks at the base of the 1,000-m-high, fractured and unstable south flank before 3.6 ka. Countless explosive events took place inside the summit caldera during the last 9.7 ky. The last Plinian eruption, dated A.D.1000–1160, produced an andesitic pumice-fall deposit, which achieved a thickness of 25 cm 40 km SE of the summit. Minor eruptions since then show phreatomagmatic characteristics and a wide range in composition (mafic to rhyolitic): the events reported since A.D. 1550 include many degassing episodes, four moderate (VEI 2–3) eruptions, and one VEI 3 eruption in A.D. 1667.

Huaynaputina comprises three vents on the floor of an avalanche caldera open in a deeply eroded stratovolcano located on the eastern edge of a high volcanic plateau. The eruption started on 19 February 1600, lasted at least 17 days and emplaced: (1) a widespread (≥ 85000 km2)pumice-fall deposit about 8 km3 in volume; (2) several thin ash-fall layers; (4) ignimbrites ca. 1 km3 in volume with proximal lag breccia on the caldera's flanks; (3) pyroclastic-surge deposits; (5) a probable co-ignimbrite ash; (6) a crystal-rich airfall deposit; (7) a late ashfall deposit. In addition, secondary ignimbrites, mostly channeled, removed the newly-erupted tephra in the valleys that drain the high plateau. Destructive debris flows swept down the canyon of Tambo river as far as 120 km to the Pacific Ocean.

This paper presents a two-output indirect matrix converter feeding an open-ended winding induction machine. The modulation strategy for the converter input stage, which provides the DC voltage for the output stages, exploits the capability of the input rectifier to produce different DC voltage levels. Moreover, this paper includes a space vector modulation strategy for the converter output stages intended to eliminate the zero sequence load voltage. Furthermore, in order to decrease commutation losses, output stage commutation will take place at reduced voltage when load voltage requirements are low. Modulation strategies and overall system operation are verified via simulation in a PSim/Matlab platform with the machine operating under an open loop V/f control strategy. Experimental results are also presented to validate the control strategies. [ABSTRACT FROM AUTHOR]