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This article presents a method for selecting the best battery sizing based on an optimal market participation strategy in a hybrid renewable power plant. The proposed formulation considers different scenarios to ensure the reserve provision compliance and includes two terms. The first one maximizes the day-ahead and automatic frequency restoration reserve (aFRR) market revenues. The second minimizes the battery degradation, accounting for both cycling and calendar ageing effects. The Iberian Electricity Market is selected as the study case, and two different market scenarios are compared: the current market scenario and the upcoming one, in which the upward and downward aFRR band offers are independent. The operation of a set of batteries is simulated until their end of life, and results reveal that energy/power ratios higher than 3 h for the current market scenario, and than 4 h for the upcoming one, are less cost effective. Regarding the best battery energy storage systems sizing, the selection varies considering incomes or profitability criteria. Moreover, keeping the current prices, in the upcoming market scenario hybrid renewable power plants are encouraged to participate more in the downward than in the upward aFRR market. [ABSTRACT FROM AUTHOR]

The control of multi-input and multioutput (MIMO) systems with multiple time delays is difficult to be done using classical control techniques, especially if the process is not open-loop stable. Model predictive control (MPC) is the natural choice in industry for this case, but its tuning and implementation are not trivial and, in general, cannot be done in the low level of the process control system. This paper aims to show a method to design MIMO filtered Smith predictors for $n \times n$ processes with multiple time delays based on the decentralized direct decoupling structure. This method allows an easy tuning of the primary controller by simplifying the problem to multiple single loops if the realizability conditions presented in the paper are met. The proposed method can also be used in MPC to remove the interactions between process variables. The effectiveness of the method is illustrated through two case studies. [ABSTRACT FROM AUTHOR]

This paper deals with the development of a magnetic lead screw (MLS) for wave energy conversion. Initially, a brief state of the art regarding linear permanent-magnet generators and MLSs is given, leading to an introduction of the MLS and a presentation of the results from a finite-element analysis used to find the magnetic forces. Furthermore, the force per magnet surface area measure is presented as a better alternative to the force density measure, which is often used for linear magnetic devices. Based on this, the overall design of a 500-kN MLS is presented focusing on the bearing supports used to compensate for the magnetic attraction forces and the resulting deflection of the rotor. In addition, in order to avoid some of the assembling-related disadvantages of using surface-mounted magnets, an embeddedmagnet topology is proposed. To demonstrate the technology, a scaled 17-kN MLS is presented together with experimental results. [ABSTRACT FROM PUBLISHER]

In the prior literature, the small-signal incremental impedance of fluorescent lamps has been characterized using a single-pole single-zero transfer function. This transfer function provides a good estimation of the lamp dynamics at rated power. However, when this model is used at low power levels, the accuracy is severely reduced, particularly at high perturbation frequencies (5–20 kHz). In this paper, a new double-zero double-pole transfer function is used to model the lamp dynamics with great accuracy even at low power levels. The best results have been obtained using a transfer function with two real zeros and a double complex pole. Using a new characterization procedure, the small-signal model of a 26-W compact fluorescent lamp has been obtained. All the terms of the transfer function (static gain, poles, and zeros) have been calculated at different power levels. Different polynomial expressions have been used to approximate these terms as power-dependent functions. The proposed characterization procedure also allows obtaining the equivalent resistance of the electrodes. This feature has been used to measure the effect of the extra heating imposed by IEC 60901 during dimmed operation. [ABSTRACT FROM AUTHOR]

Nowadays, Permanent Emergency Lighting Systems (PELSs) are widely used in many applications, including emergency exit indication and lighting in critical or strategic points. Limitation in operation hours in classical lamps (10 000-20 000 h for fluorescent lamps) implies short lamp replacement times and, therefore, high maintenance costs. This paper shows an alternative solution based on high-efficiency LEDs. The long operation life (above 100 000 h) of high-efficiency LEDs with a very simple electronics circuitry implies an interesting solution for these types of applications. A 30-lm and 1-h PELS has been built and tested. A low-cost power supply has been built and used as a battery charger and LED driver. [ABSTRACT FROM AUTHOR]

This paper deals with the use of microprocessor-based control circuits in automotive and railway lighting applications. Thus, the design and implementation of an electronic ballast for fluorescent lamps using a low-cost microcontroller (μC) is presented. The ballast has been especially developed for lighting applications in railways, where the International Union of Railways (UIC) 555 Code must be fulfilled. The μC is used to optimize the lamp ignition and supply, and to regulate lamp power against line voltage, thus fulfilling UIC 555 requirements. Also, protection features such as lamp soft reignition, overcurrent, and undervoltage are included using the μC. [ABSTRACT FROM AUTHOR]

In this paper, a low-cost electronic ballast for high-pressure sodium vapor lamps is presented. The proposed ballast is a two-stage circuit that requires only one switch and one inductor for each stage. The power-factor-correction stage is a buck dc-to-dc converter operating in discontinuous conduction mode to meet the IEC-61000-3-2 Class C requirements. The inverter stage is a low-cost nonresonant topology, based on a buck-boost inverter controlled by means of a specific current-mode control implementation. In addition, a novel and simple circuit, compatible with the presented inverter, is proposed to ignite the lamp. Furthermore, this circuit implementation provides protection against broken lamps. [ABSTRACT FROM AUTHOR]

In this paper, a novel topology to supply metal halide (MH) lamps using sinusoidal waveform with superposed third harmonic is proposed. By employing this technique, the lamp is supplied with an approximated square waveform, but it reduces the harmonic content and, therefore, electromagnetic interference and radio-frequency interference. The proposed topology is analyzed and designed for a 35-W MH lamp with ceramic discharge tube. Experimental results prove that lamp operation is stable at operating frequencies where acoustic resonances were previously observed when supplied with purely sinusoidal waveforms. In conclusion, the proposed technique could be a feasible solution for stable operation of MH lamps. [ABSTRACT FROM AUTHOR]