International Journal of Research in Science & Technology

5-8

Authors: A.Bala Alagu Raja, S.Ajin, R.Suja, A. Subanth Williams

In this paper discussed about low voltage ride through (LVRT) scheme for permanent magnet synchronous generator (PMSG) and wind energy conversion system. Wind generation system has potential application for the grid support. The voltage of the direct driven permanent magnet wind generators (PMSG) is variable due to the intermittent nature of the wind energy. With increasing penetration of wind turbine (WTs) in the grid. Grid connection codes in most countries require that WTs should remain connected to the grid to maintain the reliability during and after a short-term fault. The controllers for grid-side converters are coordinated to provide fault ride-through capability. The generator side is forced by space vector modulation and grid implemented field oriented control (FOC).

16-19

Authors: M. Jesu Selva Berozemine, A. Chitra, M. Mahalaksmi

This paper presents the review of step down converter with efficient ZVS operation. The designed buck converter uses ZCS technique and the function is realized so that the power form is converted from 12V DC 5V DC (1A). A detailed analysis of zero current switching buck converters is performed and a mathematical analysis of the mode of operation is also presented. In order to reduce the switching losses in associated with conventional converters; resonant inductor and resonant capacitor (LC resonant circuit) is applied which helps to turn on-off the switch at zero current. The dc-dc buck converter receives the energy from the input source, when the switch is turned-on. The buck–buck converters have characteristics that warrant a more detailed study. The buck converters under discontinuous conduction mode /continuous conduction mode boundary.

25-30

Authors: Kambham Ravi Shankar, Ch. Narendra Kumar and Ch. Rambabu

In modern power system consists of wide range of electrical, electronic and power electronic equipment in commercial and industrial applications. Since most of the electronic equipment’s are nonlinear in nature these will induce harmonics in the system, which affect the sensitive loads to be fed from the system. These problems are partially solved with the help of LC passive filters. However, this kind of filter cannot solve random variation in the load current wave form and voltage wave form. Active filters can resolve this problem. However, the cost of active filters is high. They are difficult to implement in large scale. Additionally, they also present lower efficiency than shunt passive filters. One of the many solutions is the use of a combined system of shunt and active series filters like Unified Power Quality Conditioner (UPQC) which aims at achieving a low cost under highly effective control. The UPQC device combines a shunt active filter together with a series active filter in a back-to-back configuration, to simultaneously compensate the supply voltage and the load current or to mitigate any type of voltage and current fluctuations and power factor correction in a power distribution network, such that improved power quality can be made available at the point of common coupling. The control strategies are modeled using MATLAB/SIMULINK. The performance is also observed under influence of utility side disturbances such as harmonics and voltage sags. The simulation results are compared without and with UPQC for the verification of results.