To enhance the band width usage with adding cyclic prefix and pilot insertion, wavelet based OFDM is employed for performance increment using BER analysis. This also classified on AWGN, RICIAN, RAYLEIGH and NAKAGAMI channels for BER performance based on SNR. These results as numerically compared with original OFDM, FRFT-OFDM

ABSTRACT:Modern power utilities have to respond to a number of challenges such as growth of electricity demand especially in non-linear loads in power grids; consequently,That higher power quality should be considered. In this paper, DPFC which is similar to unified power flow controller (UPFC) in structure, which is used to mitigate the voltage sag and swell as a power quality issue. Unlike UPFC, the common dc-link in DPFC, between the shunt and series converter devices should be eliminated and three-phase series converter is divided to several single-phase series distributed converters through the power transmission line. And also to detect the voltage sags and find out the three single-phase reference voltages of DPFC, the synchronous reference frame method is proposed. Application of DPFC in power quality enhancement is simulated in Mat lab/Simulink environment which show the effectiveness of the proposed structure KEYWORDS: FACTS, power quality, sag and swell mitigation, distributed power flow controller.

A new soft-switching boost converter is proposed in this paper. The conventional boost converter generates switching losses at turn ON and OFF, and this causes a reduction in the whole system’s efficiency. The proposed boost converter utilizes a soft switching method using an auxiliary circuit with a resonant inductor and capacitor, auxiliary switch, and diodes. Therefore, the proposed soft-switching boost converter reduces switching losses more than the conventional hard-switching converter. The efficiency, which is about 91% in hard switching, increases to about 97% in the proposed soft-switching converter. In this paper, the performance of the proposed soft-switching boost converter is verified through the theoretical analysis, simulation, and experimental results.

The Implementation of Quasi-Z-Source Four-Leg Inverter with PV by using Model Predictive Control Scheme is proposed in this paper. In order to reduce the drawbacks of traditional three phase voltage source inverter (VSI). Photovoltaic (PV) is a term which converts the light into electricity. This topology features a wide range of voltage gain which is suitable for applications in renewable energy-based power systems, where the output of the renewable energy sources varies widely with operating conditions such as wind speed, solar irradiation and temperature. To improve the capability of the controller, an MPC scheme is used which implements a discrete-time model of the system. The controller handles each phase current independently, which adds flexibility to the system. The performance of quasi z source three-phase four-leg VSI with PV by using model predictive control (MPC) was simulated using MATLAB Simulink under balanced and unbalanced load conditions as well as single-phase open-circuit fault condition.