Faculty Publications
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Item Recent developments in control schemes of BLDC motors(2006) Vinatha Urundady, U.; Pola, S.; KPVittalThis paper presents a technical review of published literature addressing control schemes for BLDC motors. The control methods reviewed include sensor less control, PWM techniques used, various methods for rotor position detection and initial rotor position detection methods.Item Simulation of four quadrant operation & speed control of BLDC MOTOR on MATLAB / SIMULINK(2008) Vinatha Urundady, U.; Pola, S.; Vittal, K.BLDC motors have been gaining attention from various Industrial and household appliance manufacturers, because of its high efficiency, high power density and low maintenance cost. After many research and developments in the fields of magnetic materials and power electronics, their applications to electric drives have increased to a significant extent. In this paper, the modeling of Brushless DC motor drive system along with control system for speed and current has been presented using MATLAB / SIMULINK. In order to evaluate the model, various cases of simulation studies are carried out. Test results thus obtained show that, the model performance is satisfactory.Item Interconnection of wind-solar hybrid Renewable Energy source to the 3 phase-3 wire distribution system along with power quality improvements at the grid side(Institute of Electrical and Electronics Engineers Inc., 2015) Gururaj, M.V.; Vinatha Urundady, U.; Jayasankar, V.N.Scarcity of power has been one of the nightmare issues for mankind in the modern age. Renewable Energy Sources (RES) working parallel with conventional power plants are playing a lead role in narrowing the difference between supply and demand. Among all the available renewable energy sources wind-solar hybrid systems are the most popular one. Due to their natural advantage of being complimentary to each other, they are assuring reliability to the utility. Power quality issues arising due to the usage of non-linear loads at the point of common coupling are addressed with the help of power electronic device interfacing RES to the grid. The work presented in this paper consists of Modeling and Simulation of wind-solar hybrid energy system and interfacing it to the grid through the interfacing inverter. A suitable control strategy which will add shunt active filter functionality to the RES interfacing device to the grid is also undertaken. © 2015 IEEE.Item Electrical collector topologies for offshore wind power plants: A survey(Institute of Electrical and Electronics Engineers Inc., 2016) Srikakulapu, R.; Vinatha Urundady, U.This paper gives an overview of various collector topologies for offshore wind farms. A comparative analysis of different DC and AC collector system topologies for offshore wind power plant are presented. The advantages and disadvantages of collector system topologies in terms of cost, reliability and efficiency are discussed. The paper discusses various updated collector topologies like radial, single sided ring, double sided ring, star and hybrid AC-DC etc. in AC collector systems and series, parallel, hybrid and matrix interconnected topology etc in DC collector systems. At the end alternative topologies based on bypassing method for radial, double sided topology are explained. © 2015 IEEE.Item Hybrid PV/wind energy system with a centralized DC bus architecture and power regulation(Institute of Electrical and Electronics Engineers Inc., 2016) Sherpa, L.; Vinatha Urundady, U.; Rai, B.This paper presents a model of hybrid energy system (HES) consisting of wind energy system (WES) and solar photovoltaic (PV) solar system connected with the grid and its performance is examined under load variation and systems input parameters. A centralized DC bus Architecture power generation is used for the proposed HES that includes a Shockley diode equation PV array and wind turbine driven by a PMSG, along with a separate DC-DC converters, a three-phase diode rectifier bridge, a dc bus and voltage source inverter (VSI) with a current regulated PWM. For a proper interfacing with the grid a suitable power conditioning system has to be implemented. The utility grid generally requires the generation of high quality electric power. A three-phase DCAC voltage source inverter (VSI) using IGBTs is employed in interfacing with the grid through sinusoidal pulse width modulation (PWM) techniques. The main objective in this paper is the analysis of HES interfaced with grid and with PQ control technique of VSI output and filtering out the high frequency harmonics produced at inverter terminal using LC filter. The performances of proposed HES are examined under dynamic conditions such as changes in input parameters and changes in load. The applicability of these HES is completely modeled and analyzed in MATLAB/Simulink environment and output results obtained are examined to be of satisfactory. © 2015 IEEE.Item Speed control of BLDC motor using bridgeless SEPIC PFC with coupled inductors(Institute of Electrical and Electronics Engineers Inc., 2016) Prabhu, P.; Vinatha Urundady, U.In this paper Bridgeless (BL) Sepic PFC with Coupled Inductors (CIs) is proposed for controlling the DC voltage of Three phase VSI to control the speed of BLDC motor. DC voltage control method enables 3 phase VSI to operate at fundamental frequency and thus reduces switching losses. Sepic converter provides output voltage of positive polarity and allows both step up and step down of input voltage in order to facilitate for the speed control of motor over a wide range. Discontinuous Conduction Mode (DCM) operation of Sepic converter, automatically shapes input current. Thus provides inherent Power Factor Correction (PFC). Also it eliminates the necessity of inner current loop and thereby reduces the number of sensors required. For the same power requirement, if CIs are introduced in the power circuit of BL Sepic, it results in reduction in size and cost of the system. This also gives improved efficiency due to the reduction in core loss. 500 W BL Sepic PFC with CIs is designed ensuring its operation in DCM to supply DC voltage in the range 70 V-310 V for a BLDC motor rated 375 W, 310 V and 3000 rpm. The proposed system is simulated for above range of voltages and performance is analysed. Results indicate that BL Sepic with CIs gives better performance with regard to efficiency and THD in addition to the reduction in overall size of converter. © 2016 IEEE.Item Implementation of adaptive fuzzy controller in a grid connected wind-solar hybrid energy system with power quality improvement features(Institute of Electrical and Electronics Engineers Inc., 2016) Jayasankar, V.N.; Vinatha Urundady, U.Energy demand increases rapidly, utilization of renewable energy resources plays an important role in narrowing down the supply-demand difference. Introduction of more power electronic devices and non-linear loads pollutes the grid and create power quality problems. Both the scarcity of energy problem and power quality problem can be simultaneously solved by using the grid interfacing inverter of renewable sources, as a shunt active filter. A suitable control strategy has to be used for giving grid interfacing inverter, the power of power quality improvement. Conventional PI controller can be replaced with a fuzzy controller for better control, and thus improve the system performance. In this paper, a grid connected hybrid system of wind-solar with power quality improvement features is simulated with a PI controller, and then results are compared by replacing PI with fuzzy controller. © 2016 IEEE.Item A study on hybrid Renewable Energy Source interface to the non-ideal grid at distribution level with power quality improvements(Institute of Electrical and Electronics Engineers Inc., 2016) Jayasankar, V.N.; Gururaj, M.V.; Vinatha Urundady, U.Air pollution is one of the prominent issues that we are facing nowadays. The major contributor for air pollution is the waste output of power plants which uses fossil fuels to generate power. Urbanization and industrialization have changed the lifestyle of human society and the need for electrical energy has enhanced significantly. As the conventional energy sources are not capable of serving the purpose, the researchers have turned their face towards Renewable Energy Sources (RES). Energy sources are scattered across the globe, therefore the available green energy at the distribution level is also used to generate electricity. The hybrid combination of wind/solar systems has proved to be a reliable source to the utility. For extracting maximum power from the RES, battery bank is connected across it. Due to the problem associated with the chemical batteries the wind/solar hybrid combination is directly connected to the grid. There are many issues related to the interconnection of RES to the grid which are addressed with the growth in power electronics field. However the power quality issue occurs due to the presence of non-linear loads at the point of common coupling. Shunt active filter has proved to mitigate the problems associated with the non-linear loads. Researchers have limited their work to interconnection of RES to ideal grid voltages which is not the practical case. In this paper the wind/solar hybrid system is modeled and is interconnected to the unbalanced and distorted grid. Also, RES interfacing inverter is added with shunt active filter functionality and hence overall cost curtailment of the project can be achieved. © 2016 IEEE.Item Wind-solar grid connected renewable energy system with series active self tuning filter(Institute of Electrical and Electronics Engineers Inc., 2016) Aravind, S.; Vinatha Urundady, U.; Jayasankar, V.N.In the present scenario energy resources are being used at an alarmingly high rate. In order to ensure that younger generations are not deprived of their energy usage, India now considers wind and solar as an alternative for future energy demands. In India incidence of solar energy in land area alone is 5000 trillion kilowatt hours which exceeds the energy outcome of all possible non renewable energy reserves in India. Next higher potential after solar comes from wind which can be used for both distributed generation or grid interactive power generation using on-shore or off shore technologies. Wind/solar hybrid RES is integrated to grid using grid interface inverter which contains power electronic switches operating at high frequency. This switching may induce harmonics and unbalances in voltage and current in the grid side. Moreover with the advancement in technology a large number of power electronics based loads are used which degrades quality of power in the load side. This paper deals with modeling work and simulation of wind-solar hybrid RES and interfacing it to the grid with a power quality improvement feature. The grid interface inverter also acts as hybrid series active filter (HSAF) with Synchronous Reference Frame (SRF) method employing Self Tuning Filter (STF) to mitigate problems related to voltage unbalance and voltage harmonics in the grid side. It also makes a comparison between the conventional low pass filter and self tuning filter. A reduction in Total Harmonic Distortion (THD) could be observed with Self Tuning Filter. © 2016 IEEE.Item Optimal design of collector topology for offshore wind farm based on ant colony optimization approach(Institute of Electrical and Electronics Engineers Inc., 2017) Srikakulapu, R.; Vinatha Urundady, U.Layout of offshore wind farm (OSWF) plays a major role in capital cost of its installation. The cost of OSWF depends on the cost of electrical collector system which includes, submarine cables, number of wind turbines, offshore platforms etc. The optimal design of OSWF will give better economical outcome. This paper explains the methodology for optimal design of OSWF electrical collector system and cost model of collector system. The methodology is based on the combination of Ant Colony optimization and Travelling Salesman problem. The objective is to minimize the length of submarine cable connected between wind turbines in wind farm. It will reduce the cost of cable and cable power loss. With the help of North Hoyle OSWF connected with 30 wind turbines, the optimization approach designs optimal OSWF based on minimum length of cable for radial and ring topologies. © 2016 IEEE.