Parameter Estimation of Modified Double-Diode and Triple-Diode Photovoltaic Models Based on Wild Horse Optimizer

The increase in industrial and commercial applications of photovoltaic systems (PV) has a significant impact on the increase in interest in studying the improvement of the efficiency of these systems. Estimating the efficiency of PV is considered one of the most important problems facing those in charge of manufacturing these systems, which makes it interesting to many researchers. The difficulty in estimating the efficiency of PV is due to the high non-linear current–voltage characteristics and power–voltage characteristics. In addition, the absence of ample efficiency information in the manufacturers’ datasheets has led to the development of an effective electrical mathematical equivalent model necessary to simulate the PV module. In this paper, an application for an optimization algorithm named Wild Horse Optimizer (WHO) is proposed to extract the parameters of a double-diode PV model (DDM), modified double-diode PV model (MDDM), triple-diode PV model (TDM), and modified triple-diode PV model (MTDM). This study focuses on two main objectives. The first concerns comparing the original models (DDM and TDM) and their modification (MDDM and MTDM). The second concerns the algorithm behavior with the optimization problem and comparing this behavior with other recent algorithms. The evaluation process uses different methods, such as Root Mean Square Error (RMSE) for accuracy and statistical analysis for robustness. Based on the results obtained by the WHO, the estimated parameters using the WHO are more accurate than those obtained by the other studied optimization algorithms; furthermore, the MDDM and MTDM modifications enhanced the original DDM and TDM efficiencies.

Inductance Gradient Calculations of EMFY-3 Electromagnetic Launcher

<div>ASELSAN Inc. has been working on electromagnetic launch technologies since 2014. The first prototype, EMFY-1, has a 25 mm × 25 mm square bore and 3-m-length rails. The second prototype, EMFY-2, has a 50 × 50 mm square bore and 3-m-length. In this paper, a recently developed prototype, EMFY-3, is presented, which has a 50 × 75 mm rectangular bore and 6-m-length. The input energy of the PPS is doubled to 8 MJ, and the 2.91 MJ muzzle energy is obtained up to now. Rail currents, breech, and muzzle voltages are measured to investigate electromagnetic calculations. Velocity curves are captured with Doppler radar, which enables us to establish propulsive inductance gradient L0pr transients empirically. The results confirm that L0 pr is constant throughout the launch, as no significant breaking mechanism occurs with the non-magnetic containment. However, a slight variation (%2 at maximum) happens from one launch to another with different rails’ current magnitudes. The transition phenomenon is a candidate for the drop in the L0 pr, as it occurs more likely at launches with higher linear current densities.</div>

Inductance Gradient Calculations of EMFY-3 Electromagnetic Launcher

<div>ASELSAN Inc. has been working on electromagnetic launch technologies since 2014. The first prototype, EMFY-1, has a 25 mm × 25 mm square bore and 3-m-length rails. The second prototype, EMFY-2, has a 50 × 50 mm square bore and 3-m-length. In this paper, a recently developed prototype, EMFY-3, is presented, which has a 50 × 75 mm rectangular bore and 6-m-length. The input energy of the PPS is doubled to 8 MJ, and the 2.91 MJ muzzle energy is obtained up to now. Rail currents, breech, and muzzle voltages are measured to investigate electromagnetic calculations. Velocity curves are captured with Doppler radar, which enables us to establish propulsive inductance gradient L0pr transients empirically. The results confirm that L0 pr is constant throughout the launch, as no significant breaking mechanism occurs with the non-magnetic containment. However, a slight variation (%2 at maximum) happens from one launch to another with different rails’ current magnitudes. The transition phenomenon is a candidate for the drop in the L0 pr, as it occurs more likely at launches with higher linear current densities.</div>

Measurement of parameters of the superconducting non-insulated coils

The electrical characteristics of superconducting coils with non-insulated windings are studied. The procedures for measuring the parameters of uninsulated superconducting windings are described. In particular, the inductance is measured by voltage with a linear current input at a given rate. Attention is focused on the impossibility of correctly determining the inductance in a winding with an uninsulated superconductor in a normal state. It is noted that in a superconducting state at currents below the critical value, the inductance of the winding is comparable to the inductance with an insulated wire. The results of measurements of inductance, radial resistance, static current-voltage and magnetic characteristics of two tape coils with non-insulated superconducting windings, one of which had a soldered connection, are presented. Conditions for measuring the parameters of non-insulated superconducting windings are formulated when they are compared with insulated windings.

AC–DC Flyback Dimmable LED Driver with Low-Frequency Current Ripple Reduced and Power Dissipation in BJT Linearly Proportional to LED Current

In this paper, a dimmable light-emitting diode (LED) driver, along with the low-frequency current ripple decreased and the bipolar junction transistor (BJT) power dissipation reduced, is developed. This driver is designed based on a single-stage flyback converter. On the one hand, the low-frequency output current ripple reduction is based on the physical behavior of the linear current regulator. On the other hand, when the voltage across the LED string is decreased/increased due to dimming or temperature, the output voltage of the flyback converter will be automatically regulated down/up, thereby making the power dissipation in the BJT linearly proportional to the LED current. By doing so, not only the power loss in the linear current regulator will be decreased as the LED current is decreased or the LED temperature rises, but also the output current ripple can be reduced. Furthermore, the corresponding power factor (PF) is almost not changed, and the total harmonic distortion (THD) is improved slightly. In addition, the LED dimming is based on voltage division. Eventually, a 30 W LED driver, with an input voltage range from 85 to 295 Vrms and with 24 LEDs in series used as a load, is developed, and accordingly, the feasibility of the proposed LED driver is validated by experimental results.