In this paper a second-order data-driven Active Disturbance Rejection Control (ADRC) is merged with a proportional-derivative Takagi-Sugeno Fuzzy (PDTSF) logic controller, resulting in two new control structures referred to as second-order data-driven Active Disturbance Rejection Control combined with Proportional-Derivative Takagi-Sugeno Fuzzy Control (ADRC–PDTSFC). The data-driven ADRC–PDTSFC structure was compared with a data-driven ADRC structure and the control system structures were validated by real-time experiments on a nonlinear Multi Input-Multi Output tower crane system (TCS) laboratory equipment, where the cart position and the arm angular position of TCS were controlled using two Single Input-Single Output control system structures running in parallel. The parameters of the data-driven algorithms were tuned in a model-based way using a metaheuristic algorithm in order to improve the efficiency of energy consumption.

In this paper, a new analytical approach is proposed to investigate the electrical and mechanical behavior of a low-power permanent magnet synchronous generator (PMSG) in the presence of a wind gust. The proposed model for the wind gust and wind power system was analytically investigated using the optimal auxiliary functions method (OAFM), which has proven to be a reliable tool. The reaction of the system to a wind gust was explicitly obtained, which is useful for stability analysis, protection issues, and risk assessment concerning the PMSG. A substantial reduction of computations in analytically analysing a complicated dynamical system is ensured by this new approach, through some auxiliary functions and convergence-control parameters.

In this paper we propose a strategy based on past/present values provided by each sensor of a network for detecting their malicious activity. Basically, we will compare at each moment the sensor's output with its estimated value computed by an autoregressive predictor. In case the difference between the two values is higher then a chosen threshold, the sensor node becomes suspicious and a decision block is activated.

This paper proposes an easily understandable Grey Wolf Optimizer (GWO) applied to the optimal tuning of the parameters of Takagi-Sugeno proportional-integral fuzzy controllers (T-S PI-FCs). GWO is employed for solving optimization problems focused on the minimization of discrete-time objective functions defined as the weighted sum of the absolute value of the control error and of the squared output sensitivity function, and the vector variable consists of the tuning parameters of the T-S PI-FCs. Since the sensitivity functions are introduced with respect to the parametric variations of the process, solving these optimization problems is important as it leads to fuzzy control systems with a reduced process parametric sensitivity obtained by a GWO-based fuzzy controller tuning approach. GWO algorithms applied with this regard are formulated in easily understandable terms for both vector and scalar operations, and discussions on stability, convergence, and parameter settings are offered. The controlled processes referred to in the course of this paper belong to a family of nonlinear servo systems, which are modeled by second order dynamics plus a saturation and dead zone static nonlinearity. Experimental results concerning the angular position control of a laboratory servo system are included for validating the proposed method.

Silicon-based tandem solar cells incorporating low-cost, abundant, and non-toxic metal oxide materials can increase the conversion efficiency of silicon solar cells beyond their conventional limitations with obvious economic and environmental benefits. In this work, the electrical characteristics of a metal oxide thin-film heterojunction solar cell based on a cuprous oxide (Cu2O) absorber layer were investigated. Highly Al-doped n-type ZnO (AZO) and undoped p-type Cu2O thin films were prepared on quartz substrates by magnetron sputter deposition. The electrical and optical properties of these thin films were determined from Hall effect measurements and spectroscopic ellipsometry. After annealing the Cu2O film at 900 °C, the majority carrier (hole) mobility and the resistivity were measured at 50 cm2/V·s and 200 Ω·cm, respectively. Numerical modeling was carried out to investigate the effect of band alignment and interface defects on the electrical characteristics of the AZO/Cu2O heterojunction. The analysis suggests that the incorporation of a buffer layer can enhance the performance of the heterojunction solar cell as a result of reduced conduction band offset.

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Research on silicon-based tandem heterojunction solar cells (STHSC) incorporating metal oxides is one of the main directions for development of high-efficiency solar cells. In this work, the optical characteristics of a STHSC consisting of a ZnO/Cu 2 O subcell on top of a silicon-based subcell were studied by optical modelling. Cu 2 O is a direct-gap p-type semiconductor which is attractive for application in solar cells due to its high absorptance of ultra-violet and visible light, nontoxicity, and low-cost producibility. Highly Al-doped ZnO and undoped Cu 2 O thin films were prepared on quartz substrates by magnetron sputter deposition. Thermal annealing of the Cu 2 O layer at 900˚C enhances the electrical properties and reduces optical absorption, presumably as a result of increased grain size. Hall effect measurements show that the majority carrier (hole) mobility increases from 10 to 50 cm 2 /V⋅s and the resistivity decreases from 560 to 200 Ω⋅cm after annealing. A Cu 2 O absorber layer of 2 µm thickness will generate about 10 mA/cm 2 of photocurrent under AM1.5G illumination. The optical analysis of the STHSC involved calculating the spectral curves for absorptance, transmittance, and reflectance for different thicknesses of the thin film layers constituting the ZnO/Cu 2 O subcell. The complex refractive indices of the thin films were derived from spectroscopic ellipsometry measurements and implemented in the simulation model. The lowest reflectance and highest transmittance for the ZnO/Cu 2 O subcell are obtained for a thickness of approximately 80 nm for both the top How to cite this paper: Nordseth, Ø.,

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