K. Vijayakumar

Wind-Driven SEIGs for Supplying Isolated Loads Employing DSP Based Power Electronic Controllers

A DSP based closed-loop system has been developed for wind-driven three-phase Self-Excited Induction Generators (SEIGs) using a diode bridge rectifier (DBR) followed by an IGBT inverter. This system is meant for supplying isolated ac loads with a voltage of constant magnitude and frequency, for any operating condition of varying nature of wind speed and consumer load. The configuration and implementation of this proposed system have been fully described. The detailed method of analysing and predetermining the performance characteristics of such stand-alone systems has also been explained. Test results obtained on an SEIG operated with the controller built in the laboratory, demonstrate the successful working of both the hardware and software of the control scheme and the usefulness of the set-up as a whole for supplying isolated ac loads. With the varying nature of wind speed, a method of meeting the power balance between the wind power available and the load power requirement has also been explained with extensive Simulation studies.

A Simple Feed Forward Controller for Stand-Alone Wind-Driven Permanent Magnet Synchronous Generator

A simple feed forward controller for wind-driven Permanent Magnet Synchronous Generator (PMSG) has been proposed using low cost opamps and a MOSFET inverter. The controller automatically adjusts the pulse widths of the inverter to maintain a constant ac voltage of desired frequency despite the variations in the voltage and frequency of PMSG output. A prototype of the system has been built by fabricating the controller, an uncontrolled diode bridge and a single-phase MOSFET inverter. The controller has been tested on a 4-pole, three-phase, 110V, 5kW, 1500 rpm PMSG driven by a wind turbine in dynamic conditions. The results of the experimental study are furnished in the paper. I. INTRODUCTION It is well known that the design and development of renewable energy sources is strongly encouraged now-a-days due to fast depletion of conventional energy sources and the environmental pollution caused by them. Among various renewable energy sources, wind energy electric conversion system can produce significant quantum of electrical power output, in locations identified with fairly high/moderate wind velocity over most part of the year. Further such wind energy electric conversion systems require a suitable electrical generator to be interfaced with the wind turbine. Induction generators are the most widely used machines in wind applications.

A modified power electronic converter topology for stand-alone photovoltaic power generation system

This paper presents a modified power electronic converter topology for photovoltaic water pumping system for agricultural irrigation. The proposed topology employs a general H-bridge inverter with front end buck converter. By using the configuration with suitable firing pulse to the buck converter, any number of levels in the output of the inverter can be produced. In the proposed converter, the duty cycle of the buck converter is appropriately adjusted to produce M-level unidirectional piecewise output. The unidirectional stepped wave is inverted by an H-bridge inverter which produces a stepped AC waveform, with the level of N=2M−1. The proposed modified topology has employed with a lesser number of switches as compared to the conventional multilevel inverter topologies. The entire system was simulated using MATLAB/Simulink platform and results are furnished. Further, total harmonic distortion analysis of the proposed converter with water pumping system have been carried out and presented in this paper.