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Öğe Ageing of Photovoltaic Cells Under Concentrated Light(Ieee, 2015) Cotfas, D. T.; Cotfas, P. A.; Floroian, D.; Floroian, L.; Cernat, MihaiA novel Automated System for Cooling and Measurement under Concentrated Light (ASCMCL) and a new method to study the accelerated ageing of photovoltaic cells by using concentrated light are presented. The measurement system created is an autonomous one that can be used without surveillance. By using the new method proposed in this paper, the time of the ageing accelerated test is significantly reduced. The measurements performed at the Solar Technology Laboratory of Paul Scherrer Institute, Villigen, Switzerland confirm the utility of the proposed system and method.Öğe Boost Converter with Active Snubber Network(Univ Suceava, Fac Electrical Eng, 2017) Himmelstoss, Felix A.; Derin, Ali Riza; Cernat, MihaiA new concept for reducing the losses in a boost converter is described. With the help of an auxiliary switch and a resonant circuit, zero-voltage switching at turn-off and zero-current switching during turn-on are achieved. The modes of the circuit are shown in detail. The energy recovery of the turn-off is analyzed and the recovered energy is calculated; an optimized switching concept therefore is described. The influence of the parasitic capacity of the switch is discussed. Dimensioning hints for the converter and the design of the recuperation circuit are given. A bread-boarded design shows the functional efficiency of the concept.Öğe Control of the Bed Temperature of a Circulating Fluidized Bed Boiler by using Particle Swarm Optimization(Univ Suceava, Fac Electrical Eng, 2012) Aygun, Hilmi; Demirel, Huseyin; Cernat, MihaiCirculating fluidized bed boilers are increasingly used in the power generation due to their higher combustion efficiency and lower pollutant emissions. Such boilers require an effective control of the bed temperature, because it influences the boiler combustion efficiency and the rate of harmful emissions. A Particle-Swarm-Optimization-Proportional-Integrative-Derivative (PSO-PID) controller for the bed temperature of a circulating fluidized bed boiler is presented. In order to prove the capability of the proposed controller, its performances are compared at different boiler loads with those of a Fuzzy Logic (FL) controller. The simulation results demonstrate some advantages of the proposed controller.Öğe Fault Detection in Synchronous Motor Drives, a Co-Simulation Approach(Ieee, 2015) Apostoaia, Constantin M.; Cernat, MihaiThis paper presents a multi-domain co-simulation based approach to identify faults in large power industrial three-phase synchronous motor drives. The goal is to develop an integrated simulation platform capable to capture faults caused by failing electronic components of the brushless exciter, as one of the key parts of these drives. The signal signature analysis is used for monitoring the operation of the excitation field fed through a full wave diode bridge rectifier with failing power diodes. Simulated faults of the synchronous machine are analyzed, focusing on one shorted rotor pole internal fault. The approach is based on the co-simulation of the synchronous motor finite element analysis (FEA) model, using ANSYS Maxwell (TM) software, with the brushless exciter and mechanical load models built with ANSYS Simplorer (TM).Öğe Improving the Energy Management of a Solar Electric Vehicle(Univ Suceava, Fac Electrical Eng, 2015) Guneser, Muhammet Tahir; Erdil, Erzat; Cernat, Mihai; Ozturk, TurgutA solar electric vehicle (SEV) is an electric vehicle (EV) with onboard photovoltaic cells charging a set of batteries for extended driving range. This study aimed to improve the energy management system of a SEV, called YILDIZ, using a fuzzy logic control system (FLC). A MATLAB based simulation model of three basic components of a solar car: solar cell modules, batteries and motor drive system was performed. An original FLC was developed. For proving its applicability, the performances of the SEV were tested by simulation, in accordance with the standard test drive cycle ECE-15. The characteristics obtained with the original Proportional Integral Fuzzy Logic Control (PI-FLC) were compared with those obtained with a classical Proportional Integral (PI) controller. Using the designed model, we calculated the range of YILDIZ with and without PV feeding which gave us an opportunity to study and compare both SEV and EV models on real race-track situation. Then the optimum speed, at any time, which enabled the vehicle to reach a chosen destination as quickly as possible, while fully using the available energy, was calculated. Proposed solutions tested on YILDIZ. Results of simulations were compared with YILDIZ run on the Formula-G race track in Izmit, Turkey.Öğe An Induction Motor Design for Urban Use Electric Vehicle(Ieee, 2016) Guneser, Muhammet Tahir; Dalcali, Adem; Ozturk, Turgut; Ocak, Cemil; Cernat, MihaiBecause of fossil fuel shortage and its damages on environment, electric vehicles (EV) are going to be more popular in science and car industry as well. So, EV's take an opportunity to spread over the traffic finally. But battery, which is the main energy supplier of the motor, has disadvantages as big volume and weight. Scientists try to enhance energy densities, ranges and quicken charging. All of research results force us to drive EV in a loop, close to charging stations for near future. So EV's should be designed by considering urban road and speed conditions as well. In this survey, we designed a new two pole 7,5 kW induction motor for a certain electric vehicle, which was designed to use urban drive. We considered urban traffic rules and conditions, while designing the motor. We simulated and verified analytical and finite element analysis of the designed induction motor. We also modelled and simulated the EV with the induction motor on MATLAB to observe control performance of field oriented control (FOC) on several urban use scenarios. According to our results, EV with designed motor can be realized and controlled.Öğe Noise and Vibration Monitoring for Premium Efficiency IE3 Three-Phase Induction Motors(Univ Suceava, Fac Electrical Eng, 2015) Nistor, Ciprian Gheorghe; Scutaru, Gheorghe; Campeanu, Radu; Cernat, MihaiThe paper presents the original SV-100 platform that enables low-cost and very high accuracy determinations of noise and vibration levels. The aim of the proposed platform is to achieve an effective integration of the two topics of this analysis: vibrations and noises. To the best of our knowledge, no low price, dedicated compact platform with embedded measuring instruments exists. For proving the practical utility of the proposed platform, two induction motors of 7.5 kW and 11 kW, respectively, in single-layer winding, at 1000 rpm, with IE3 premium efficiency were analyzed. This analysis is required because, according to IEC60034-30 standard, the IE3 efficiency standard has become mandatory for induction motors of rated power greater than 7.5 kW. Therefore, in order to improve the motor operating efficiency, the power losses caused by noises and vibrations have to be reduced. Several variants of supply were studied, i.e., by the three-phase 50 Hz network and by a three-phase inverter at 40, 50 and 60 Hz, respectively. The experimental determinations of noises are presented comparatively, by using a Bruel&Kjaer sonometer and by using the new platform SV-100. The results are compared with the IEC60034 standard.Öğe A Novel Sensorless Field Oriented Controller for Permanent Magnet Synchronous Motors(Ieee, 2014) Aygun, Hilmi; Gokdag, Mustafa; Aktas, Mustafa; Cernat, MihaiIn this paper, a Particle Swarm Optimization based PI controller (PSO-PI) is used for control the speed and the torque of a Permanent Magnet Synchronous Motor (PMSM) while a Model Reference Adaptive System (MRAS) based on an Artificial Neural Network (ANN) estimation mechanism is applied to estimate sensorless the speed. In order to show the capability of the proposed PSO-PI controller, it is compared with a Fuzzy-Logic PI controller and with a classical PI controller. The simulation results prove the usefulness of the proposed PSO-PI controller.Öğe Two Speed Single Phase Induction Motor with Electronically Controlled Capacitance(Univ Suceava, Fac Electrical Eng, 2014) Campeanu, Radu; Cernat, MihaiAn experimental exploration of using an Electronically Controlled Capacitor (ECC) in the supply system of a two speed single phase induction motor drive is presented. The ECC solution and the method with solution with a fixed value capacitor are comparatively analyzed in terms of efficiency and maximum torque availability. The losses and the over-voltages due to the electronic commutation are also analyzed. The paper proves the feasibility of the ECC solution and underlines its advantages and drawbacks. The optimal value of the switching frequency of ECC has been experimentally determined.
