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When the panels in a photovoltaic (PV) array are subjected to a nonuniform irradiance level, some bypass diodes may turn <sc>on</sc>, and the overall power production might be affected significantly. An increase of the power delivered by the whole array might be obtained by means of its electrical reconfiguration, that is, the change of the series–parallel connection among the panels of...
In the photovoltaic (PV) systems, the main objective of the control strategy is to extract the maximum power from the source; usually such objective is obtained by combining the action of the MPPT algorithm with a voltage regulator used to attenuate the disturbances at the source terminals. This work proposes an automatic procedure for designing the parameters of the voltage compensation network by...
After modelling accurately the Ćuk converter operating in discontinuous inductor conduction mode, a state-feedback control strategy based in the subsequent linearized small-signal full-order model is designed. The resulting closed-loop dc-dc converter exhibits good output voltage regulation even in presence of step and high frequency perturbations in input voltage, load and control signal. The analytical...
The development on photovoltaic (PV) applications along with recent breakthroughs in power electronics and processors technologies, has became in a strong research area especially in modeling and control techniques, for which digital controllers offer some advantages over analog controllers; however their design does not always lead to accurate performances. This paper proposes to adopt an analog...
A grid-connected photovoltaic system, based on a sixth-order dc/dc converter with a non-linear compensation technique, is proposed. This solution addresses the main challenges in double-stage photovoltaic systems connected to the grid: increase the dc/dc stage voltage conversion ratio, reduce the photovoltaic voltage ripple, avoid electrolytic capacitances, and mitigate the effect of dc-link voltage...
In this paper a symbolic analysis of the equations that allow to calculate the values of the series and parallel resistances appearing in the single diode model of a photovoltaic module is presented. Such a model requires the identification of five values, that are the photo-induced current, the diode ideality factor and saturation current, the series and parallel resistances. This calculation can...
In this paper a novel multi variable maximum power point tracking algorithm is introduced. The method is suitable for distributed photovoltaic applications and, in contrast with the concept of using a power optimizer for each module working independently from the others, the architecture used in this paper is based on the adoption of a centralized controller for distributed DC/DC converters. The technique...
This paper presents a mathematical procedure for modeling rectangular (N rows with M modules each) and non-rectangular photovoltaic (PV) arrays in Total Cross-Tied (TCT) configuration operating in uniform and mismatching conditions. The proposed model uses the simple single diode representation for each PV module; then each row of the TCT array is represented as an equivalent non-linear PV circuit...
This paper proposes the use of a predictive controller to regulate a dc/dc converter interacting with a photovoltaic generator and a grid-connected inverter. The proposed solution rejects perturbations generated by environmental conditions and inverter transients. In addition, the predictive controller is able to recover from inverter wrong operation, i.e. drive dc-link voltage under the photovoltaic...
This paper analyzed the efficiency of typical fuel cell hybrid topologies to propose a selection criteria depending on the load power profile. Also, it is presented a constraints-based robust control design to regulate the fuel cell system in safe operating conditions. This controller prevents the oxygen starvation phenomena by regulating the oxygen excess ratio. Finally, simulation results show the...
In grid-connected Photovoltaic (PV) applications, DC-links based on large electrolytic capacitors are used to attenuate voltage oscillations caused by the sinusoidal power injection into the grid, where the electrolytic capacitors introduce reliability problems. This paper proposes the unified modeling of the complete PV system in typical grid-connected operation conditions to design control strategies...
An efficient pre-filter based on interleaved DC-DC boost switching converters to mitigate high-frequency harmonics injection to power sources is proposed. The main feature of the pre-filter is to mitigate the ripple of power converters input-current, improving the efficiency of the whole power conversion chain. The pre-filter optimal operating conditions are calculated, and the circuit is modeled...
Digital controllers are an interesting option for the next Voltage Regulator Module generation due to their wide programming possibilities. This paper discloses a very interested candidate to control DC-DC power converters, the Digital Signal Controller. For that matter, a study was done by carrying out simulations and experimental results. Moreover, an additional algorithm is given in order to show...
In this paper a new approach to the minimization of fuel consumption in Polymer Electrolyte Membrane (PEM) Fuel Cell (FC) systems is presented. It is mainly based on the minimization of the current produced by the FC by means of an adaptive technique, namely the Perturb and Observe (P&O) approach. The controller works in conjunction with the dc/dc converter which processes the power produced by...
Embedded microprocessors require efficient supply management systems to optimize its power consumption and to enhance their calculation potentials. Typically, the modules performing this function are known as Voltage Regulator Modules (VRMs). It is widely adapted that current-programmed regulation techniques own leveraging skills in the control of this kind of power converters. However, these strategies...
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