abtechnosolutions

Single phase sixty three level inverter using only nine switches towards THD reduction Abstract—Thispaper deals with reduced number of switches in multilevel inverter. Asymmetrical inverter has been used with the topology of cascading the fundamental unit. The grounds behind using multilevel is forenhancing the power quality and scaling down the distortions in waveforms. The output waveform attained is quite closer to sinusoidal waveform with a very low distortion. The switching is in a sequenceand flexible for increasing or cutting down the voltage levels when desired. The switching methods with pulsewidth modulation have been discussed. And a comparative study of different topologies of symmetrical as well as asymmetrical inverter of different levels has been done. Lastly, the simulated results from Simulink/MATLAB is presented. An Improved Three-Phase Five-Level Inverter Topology With Reduced Number of Switching Power Devices This paper presents an optimized topology of 3...

Control strategy of DFIG in hybrid micro-grid using sliding mode frequency controller and observer A doubly fed-induction generator (DFIG) has a significant advantage of fast dynamic frequency regulation. However, conventional virtual inertia control (VIC) design only takes frequency into account and may face secondary frequency drop during rotor speed restoration. To solve these problems, the novel decentralised control strategy is proposed for a hybrid micro-grid. Firstly, the load disturbance is considered to enhance control system accuracy, which is estimated by using the state observer based on the dynamic mathematical model. Then, the sliding mode VIC controller is designed by taking advantage of the observed disturbance value and frequency deviation for DFIG output dynamic adjustment according to the conventional frequency control (VIC) model. Furthermore, during DFIG rotor speed restoration, pitch angle control based on the mathematical model is applied for reserve capac...