M. Padmarasan’s research while affiliated with Sathyabama Institute of Science and Technology and other places

Analysis of the design and performance of interline dynamic voltage restorer (IDVR) is proposed in this paper. It provides economical solution to face the difficulty of voltage swell. IDVR consists of series-connected voltage compensator with DC link. This paper proposes the IDVR where the two or more DVRs are connected in multiline (different feeder) for compensating the voltage swell in the transmission line. The ability of dynamic voltage restorer (DVR) is involved to inject real power to the transmission line for long period voltage swell. One of the DVR in IDVR system compensates the voltage swell, and others are connected to the DC link which replenish the energy and maintain the DC link voltage at the desired value. Series-connected compensator compensates the source-side voltage disturbance either through voltage sag or swell, correspondingly. In this paper initially open-loop control IDVR system using PWM technique has been analyzed. The simulation result has been verified using MATLAB/Simulink.

This paper deals with the implementation of interline dynamic voltage restorer (IDVR) system using three-phase inverter integrated with PLL based MSRF controller for regulating the DC link voltage, and reducing the voltage sag. Voltage variation that frequently occurs either in the form of voltage sag or swells and it can cause major damage to the environment and distribution station. In this paper, interline dynamic voltage restorer has proposed which consist of more than one DVR's are commonly connected with the DC link capacitor of the system. Suitable control methods are developed for reduce the voltage sag in the line. Modified synchronous reference frame control has designed and implemented for both controls, and compensation of voltage sag. Conventional control method has some constraints such as high settling time of dc link voltage, and increase in harmonics that could be overcome by a new approach of MSRF based PLL has presented in this paper, which helps to compensate the voltage sag occurs in the system. Furthermore design and analysis of MSRF based IDVR is proposed to improve the efficiency, reducing the settling time of DC link voltage, reducing the harmonics distortion, and minimize the power quality issues by using MATLAB/SIMULINK.

In this paper discuss the new approach for improving displacement factor using an Interline Dynamic Voltage Restoring and Displacement Factor Controlling Device (IVDFC) in a distribution system. An Interline Dynamic Voltage Restorer (IDVR) is perpetually engaged in distribution systems to mitigate voltage sag/swell problems. An IDVR simply consists of numerous dynamic voltage restorers (DVRs) sharing a common dc link connecting independent feeders to safe electric power to critical loads. The IDVR is operated that it hold the voltage across the critical load bus terminals constant at system nominal frequency irrespective of the changes occurring in source voltages frequency. While one of the DVRs compensates for the local voltage sag in its feeder, the other DVRs reload the common dc-link voltage. For normal voltage levels, the DVRs should be bypassed. Instead of bypassing the DVRs in normal conditions, this paper proposes operating the DVRs, if needed, to improve the displacement factor (DF) of one of the involved feeders. DF improvement can be achieved via active and reactive power exchange (PQ sharing) between different feeders. To successfully apply this concept, several constraints are addressed throughout the paper. The simulation model for this system is developed using MATLAB which is shown that the voltage across the critical load is regulated completely.

In this study the conventional inverter interfacing renewable energy sources with the grid, without any additional hardware cost. Here, the main idea is the maximum utilization of inverter rating which is most of the time underutilized due to intermittent nature of RES. Based on the non-linear characteristics of PV, these thesis designs a VSS controller to realize the maximum power output of PV arrays. The output power from renewable energy sources fluctuates because of weather variations. This study proposes an effective power quality control strategy of renewable energy sources connected to power system using Photovoltaic (PV) array. If the main controller used is a PR controller, any dc offset in a control loop will propagate through the system and the inverter terminal voltage will have a nonzero average value. In this strategy both load and inverter current sensing is required to compensate the load current harmonics. The non-linear load current harmonics may result in voltage harmonics and can create a serious PQ problem in the power system network.

A variable speed cage type Induction Generator system is simulated and implemented. The complete model consists of Induction Generator, PWM converter, PWM inverter and local load. The system studied maintains constant voltage when the speed is fluctuating. The advantages of PWM rectifier and PWM inverter are utilized. Circuit model for variable speed induction generator is developed and the simulation is done with resistive load, RL load and induction motor load. PWM rectifier has improved input Power factor and PWM inverter has reduced harmonics at the output. Simulation studies performed on the circuit model for variable speed cage machine wind generation unit show that the output voltage is constant even as the load changes.

This paper deals with the simulation and implementation of Boost Power Factor Correction (PFC) Converter along with Electro Magnetic Interference (EMI) Filter. The Boost Converter of PFC Circuit is analyzed, designed and simulated with resistive load. Near unity power factor is obtained by using Boost PFC Converter with EMI Filter. The laboratory model is implemented and the experimental results are obtained. These experimental results are correlated with the simulation results.

This paper proposes a new real and reactive power coordination controller for a unified power flow controller (UPFC). UPFC has two converters, one is series converter which controls the transmission line real or reactive power flow and other is the shunt converter which controls the bus voltage or shunt reactive power and DC link capacitor voltage. In steady state, the real power demand of the series converter is supplied by the shunt converter of the UPFC. The need for reactive power coordination controller for UPFC arises from the fact that excessive bus voltage (the bus to which the shunt converter is connected) excursions occur during reactive power transfers. A new reactive power coordination controller has been designed to limit excessive voltage excursions during reactive power transfers.