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Öğe DSP implementation of a PV system with GA-MLP-NN based MPPT controller supplying BLDC motor drive(PERGAMON-ELSEVIER SCIENCE LTD, 2007) Akkaya, R.; Kulaksiz, A. A.; Aydogdu, O.This paper presents a brushless dc motor drive for heating, ventilating and air conditioning fans, which is utilized as the load of a photovoltaic system with a maximum power point tracking (MPPT) controller. The MPPT controller is based on a genetic assisted, multi-layer perceptron neural network (GA-MLP-NN) structure and includes a DC-DC boost converter. Genetic assistance in the neural network is used to optimize the size of the hidden layer. Also, for training the network, a genetic assisted, Levenberg-Marquardt (GA-LM) algorithm is utilized. The off line GA-MLP-NN, trained by this hybrid algorithm, is utilized for online estimation of the voltage and current values in the maximum power point. A brushless dc (BLDC) motor drive system that incorporates a motor controller with proportional integral (PI) speed control loop is successfully implemented, to operate the fans. The digital signal processor (DSP) based unit provides rapid achievement of the MPPT and current control of the BLDC motor drive. The performance results of the system are given, and experimental results are presented for a laboratory prototype of 120 W. (c) 2006 Elsevier Ltd. All rights reserved.Öğe A microcontroller-based stand-alone photovoltaic power system for residential appliances(ELSEVIER SCI LTD, 2004) Akkaya, R.; Kulaksız, A. A.In this study, a stand-alone photovoltaic power system was designed and implemented to operate residential ac-powered appliances such as fluorescent lambs, fans etc. Sun-tracker is implemented for improved efficiency of the system by keeping the solar module perpendicular to the sun's incoming rays. The charge method is realized with closed-loop current control of buck-boost dc-dc converter. The proposed system also uses a voltage source type PWM inverter to convert DC voltage from battery storage to supply AC loads. In the PWM method used, selected harmonies are eliminated with the smallest number of switching and an improvement in the system efficiency by reducing switching losses and providing ease of filtering on the inverter output is obtained. Charge controller and PWM inverter systems have been realized by using PIC16F873 microcontrollers. An experimental system was implemented to demonstrate the effectiveness of the proposed system. Simulation and experimental results are given to verify the system's efficiency. (C) 2003 Elsevier Ltd. All rights reserved.Öğe Protection of Ac Motors by Means of Microcontrollers(IEEE, 2000) Çunkaş, M.; Akkaya, R.; Öztürk, A.In this study, a system was designed and implemented to make protection for the current, voltage, winding temperature of induction motors. In the system, the voltage transformer with transformation ratio of 400/5V and current transformer with transformation ratio of 25/5A were connected to each phase of induction motors. The circuit was designed for measuring the winding temperature. The sampling circuit was realized that low AC signals taken from transformers secondary windings and sensed temperature values convert into DC values. Control process was implemented by using PIC 16C84 microcontroller. To input reference values and to monitor these values, the LCD's and a keypad was added to microcontroller. sampled DC values were transmitted into the microcontroller by using Analog-Digital-Converter(ADC) unit. Measured data art compared with reference values by means of software. When a low voltage, high voltage, high current, voltage and current unbalance, high winding temperature or single phasing are sensed, the system opens its normally soft starter after a trip delay. Trip and reset delays prevent nuisance tripping due to rapidly fluctuating power line conditions. Besides, data such as current, voltage, temperature which are acquired by microprocessor are transmitted to the central PC by means of RS232C series communication line. In this wry the motor data could be observed at any moment on PC monitor. The PC then shows a message corresponding to power-system fault, and alerts the operator.Öğe A Simple Control Scheme for Single-Phase Shunt Active Power Filter with Fuzzy Logic Based DC Bus Voltage Controller(INT ASSOC ENGINEERS-IAENG, 2009) Dogan, H.; Akkaya, R.In this paper, a simple control scheme of single-phase shunt active power filter for current harmonics and reactive power compensation of linear and non-linear loads, is proposed. Simplicity of the proposed control scheme is based on uncomplicated reference source current generation and fuzzy logic based do bus voltage regulation methods. Thus, complex computations are not needed. To indicate reactive power and current harmonics compensation capability in both transient and steady state, leading and lagging power factor linear loads and uncontrolled rectifier and thyristor based ac regulator non-linear loads are connected to the system. The effectiveness of the proposed control technique is verified by the simulation results.
