STATCOM based DC Link Voltage Regulation for High Power Applications

Authors:-P. Mamatha, Shaik Mabhu Jani

Abstract:-In this paper, a simple static var compensating scheme using a cascaded two-level inverter-based multilevel inverter is proposed. The topology consists of two standard two-level inverters connected in cascade through open-end windings of a three-phase transformer. The dc-link voltages of the inverters are regulated at different levels to obtain four-level operation. The simulation study is carried out in MATLAB/SIMULINK to predict the performance of the proposed scheme under balanced and unbalanced supply-voltage conditions. A laboratory prototype is developed to validate the simulation results. The control scheme is implemented using the TMS320F28335 digital signal processor. Further, stability behavior of the topology is investigated. The dynamic model is developed and transfer functions are derived. The system behavior is analyzed for various operating conditions.

Synchronous Reference Scheme for Harmonic / Reactive Power Compensation using Hybrid Active Power Filter

Authors:-Chaitanya Tanneeru, G Ravi Kumar

Abstract:-In this Paper, a novel control strategy proposed for achieving maximum benefits like reactive power compensation and harmonics elimination in medium-voltage industrial networks using a hybrid active power filter. It proposes a hybrid filter as a combination of a three-phase, two-level, voltage-source converter connected in parallel with the inductor of a shunt, single-tuned, passive filter. This concept decreases the voltage and current stress over the elements of the active filter. Since the topology is composed of a single-tuned branch, the control algorithm also has to ensure sufficient filtering at other harmonic frequencies. We propose using a proportional-resonant, multiloop controller in order to improve the transient response and eliminate the steady state error. This controller is implemented in a synchronous-reference frame, it allows us to use half the number of resonators, compared with the solution using proportional-integral controllers in the harmonic-reference frame. The compensation performance of the proposed hybrid active power filter and the associated control scheme under steady state and transient operating conditions is demonstrated through simulations results.

DFIG based Analysis of Fault Current Characteristics under non Severe Fault Conditions

Authors:-K.Nicholaus, BHUKYA RANGA NAIK

Abstract:-In the recent times, due to environmental concerns, there is rapid growth of wind power in the electric power systems. Power system planners and operators are facing many difficulties while integrating wind power because of its inherent characteristics. To solve these difficulties there is need for various studies and models of wind turbines. Doubly Fed Induction Generator (DFIG) based Wind Turbine (WT) is one of the most popular configurations being adapted the proposed analysis method is applicable for the study of fault current characteristics of DFIG with different control strategies for low-voltage ride through. The research results are helpful to the construction of adequate relaying protection for the power grid with penetration of DFIGs.

Resistive network based resonant dc/dc converter for increasing power system efficiency

Authors:-Manoj Babu, Bhukya Ranga Naik

Abstract:-This paper presents a new topology for a highefficiency dc/dc resonant power converter that utilizes a resistance compression network (RCN) to provide simultaneous zero-voltage switching and near-zero-current switching across a wide range of input voltage, output voltage, and power levels. The RCNmaintains desired current waveforms over a wide range of voltage operating conditions.The use ofON/OFF control in conjunction with narrowband frequency control enables high efficiency to be aintained across a wide range of power levels. The converter implementation provides galvanic isolation and enables large (greater than 1:10) voltage conversion ratios, making the system suitable for large step-up conversion in applications such as distributed photovoltaic converters. Experimental results from a 200-W prototype operatingat 500 kHz show that over 95% efficiency is maintained across an input voltage range of 25–40 V with an output voltage of 400 V. It is also shown that the converter operates very efficiently over a wide output voltage range of 250–400 V, and a wide output power range of 20–200 W. These experimental results demonstrate the effectiveness of the proposed design.

DFIG based Variable Speed Wind Turbine Control to Reduce Flicker Effect using Pitch Control

Authors:- K.sameera, Shaik Mabhu Jani

Abstract:-Due to the variations wind speed variation, wind shear and tower shadow effects, grid connected wind generating systems are the sources of power which may produce fiicker during continuous operation. This paper presents a model of an high-level variable-speed wind turbine with a generator to investigate the fiicker emission and mitigation issues. An individual pitch control (IPC) strategy is proposed to reduce the flicker emission at different wind speed conditions. The IPC scheme is proposed and the individual pitch controller is designed according to the generator active power and the azimuth angle of the wind turbine. The simulations are performed on the Simulation results show that damping the generator active power by IPC is an effective means for flicker mitigation of variable speed wind generation during continuous operation.