Ramji Tiwari

Design and development of a high step-up DC-DC Converter for non-conventional energy applications

In this article a high step up DC-DC Converter which is integrated with renewable energy resources is proposed. The disadvantage of conventional converters is that it has high duty ratio and high voltage stress across power devices with less efficiency. The proposed methodology uses flyback converter to obtain high static voltage gain to improve the efficiency of the converter by reducing the voltage stress across the switch and diodes. Thus by avoiding the operation of the high duty ratio and recycling of coupled inductor stored energy, the overall efficiency of the converter gets improved.

Fuzzy Logic-Based Pitch Angle Controller for PMSG-Based Wind Energy Conversion System

A comparative analysis of different types pitch angle controller is designed in this paper to achieve a steady output torque for stable wind turbine operation. The control techniques are implemented and developed to provide a uniform constant torque to the permanent magnet synchronous generator (PMSG). The wind system consists of a wind turbine, a pitch actuator and PMSG. The control strategy used are proportional-integral (PI) and fuzzy logic controller (FLC). The performance of the control strategies is investigated in terms of aerodynamic torque, generator speed and the generator power. The complete wind energy conversion system (WECS) is developed and tested using MATLAB/Simulink. The performance of the control strategies is evaluated under varying wind-speed condition. The performance of the pitch angle controllers is found satisfactory, but the strategy with fuzzy logic-based controller shows better performance as compared to PI controller.

Coordinated DTC and VOC control for PMSG based grid connected wind energy conversion system

This paper presents an output power smoothing method by a coordinate control of machine side converter and grid side converter for permanent magnet synchronous generator (PMSG) based wind energy conversion system (WECS). The WECS adopts medium voltage source converter with AC-DC-AC configuration. The output power fluctuations are compensated using direct torque control based maximum power point controller and voltage oriented control. The DC link voltage is controlled using grid side controller and the maximum power is extracted using the machine side controller of the wind turbine. The proposed controller provides effective solution for grid integration and constant power flow from the generator system to grid system. Simulation results are presented and analysed the performance of the control strategies implemented in the system.

A Study of DC–DC Converters with MPPT for Standalone Solar Water-Pumping System

In this paper, a DC/DC converter strategy is employed for solar water-pumping application. Maximum power point tracking (MPPT) control strategy is incorporated in order to extract maximum available power from the solar irradiation. In rural areas, the fields will be normally located far from the village, so it will not be able to extend the connection from the grid to such places. Thus, here standalone PV systems will be appropriate for powering pumps and other loads on the fields. In this paper, the performance of various DC–DC converters like boost, CUK, and SEPIC with MPPT techniques like P and O, fuzzy and NN (RBFN) is studied to identify the more suitable converter for the pumping application.

Comparison Between PI Controller and Fuzzy Logic-Based Control Strategies for Harmonic Reduction in Grid-Integrated Wind Energy Conversion System

In this paper, a novel fuzzy logic-based control (FLC) strategy is developed to perform multi-function strategy for smooth and controlled operation of three-phase renewable energy system (RES)-based wind energy conversion system (WECS) with grid integration. The inverter acts as an converter to infuse the power obtained from the wind energy and as a active power filter to compensate reactive power demand and load current harmonics. The control strategies in accordance with 3-phase 4-wire unbalanced load tend to appear as a balanced linear load system at grid. The control strategy is developed and validated using MATLAB/Simulink. The proposed controller is compared with PI-based controller and validate that the proposed FLC provide better efficiency by reducing harmonics.