In this study, the common symmetrical and unsymmetrical short circuit faults in power systems are analyzed detailed. Unlike the similar studies in the literature, metallic fault conditions for unsymmetrical faults are also given in the paper additionally. For this aim, a short circuit analysis algorithm is created for the analysis of both three phase short circuit, line-to-line short circuit with fault impedance, metallic line-to-line short circuit, double line-to-ground short circuit with fault impedance, metallic double line-to-ground short circuit, line-to-ground short circuit with fault impedance and metallic line-to-ground short circuit. The obtained algorithm is established as software in MATLAB. The algorithm is applied on a sample power test system and the results are given.

In this paper, a new single phase inverter is proposed. The proposed inverter topology is obtained through modifying the well-known DC-DC buck converter to produce sine wave alternative voltage at the output. Thus, the peak value of the alternative output voltage can be provided lower than the input direct voltage value. The inverter is designed for producing alternative voltage at the output in the frequency range of 0-50 Hz. PI feedback controller is used for the control of the inverter operation. A simulation study is done for the proposed inverter and its operation in MATLAB-Simulink in order to prove its accuracy on different operation conditions. The results demonstrate that the proposed inverter can accurately produce nearly sine wave alternative voltage in various frequencies with low THD values on different operation conditions.

This study presents a new and robust single-phase inverter based on the buck-boost converter. The proposed inverter topology has minimised numbers of active and passive elements that provide less complexity and cost. Unlike similar studies in the literature, an efficient hybrid control technique is used for the control of the inverter operation. The hybrid control technique is comprised of the traditional feedback proportional-integral-derivative (PID) controller and the new proposed openloop control technique called 'control law'. This hybrid control technique provides stable and high response performance operation for the proposed inverter while the system parameters change. The proposed inverter can operate with a wide range of output frequency and output voltage value on different load conditions while satisfying <5% voltage total harmonic distortion (THD) value of the output voltage. An experimental laboratory setup with the values of 0.5 kW, 0-100 V p and 0-50 Hz is built for the proposed inverter. The experimental results demonstrate that the proposed inverter can produce high-quality output voltage with <5% THD on different input and output system parameters.

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In this paper, a new maximum power point tracking (MPPT) method based on the Fibonacci search algorithm (FSA) is proposed for the wind energy conversion system (WECS). The conventional FSA is modified according to the requirements of the WECS to improve its performance as an MPPT algorithm. The performance of the proposed method is investigated for different wind-speed profiles such as step-type and stochastically varied wind speed. Also, the modified FSA based MPPT algorithm is compared with the conventional perturb and observe (CPO) and variable-step PO (VSPO) algorithms. The simulation results approve the superior performance of the proposed method over the CPO and VSPO in terms of maximum power extracted from the system. The real-time performance of the proposed method is also investigated for varying wind conditions in the form of step-up and step-down.