Performance investigations on control strategies of DFIG fed wind energy system

Abstract

Humans race towards luxurious benefits over the years lead to rise in electrical power demand globally and rapid depletion of natural resources. This has lead to even more problems mainly environmental and energy crises. To cater the increasing energy demand, there is need to search for alternate paths for increasing the energy production globally without disturbing the ecological balance, one such solution is to produce energy using naturally available renewable sources. Among all the renewable energy sources available naturally such as solar, wind, hydro, wave and ocean. The power generation using wind energy is very good alternative due its advantages such as easily available, cost effective, rapidly developing, more commercialized, and well proven technology. Power generation using wind energy systems is one of the crucial sources that can empower the globe in a realistic way out of its present critical condition. According to the Global Wind Report, 2020 was the second-best year ever for the wind energy industry. Growth in 2021 will be just 1.8% lower than in 2020. More than 94 GW of capacity was added despite the COVID-19 pandemic in its second year. This strongly indicates the remarkable perseverance and expansion trajectory of the global wind energy industry. In this study, both Model Predictive Direct Torque Control (MPDTC) and Model Predictive Direct Power Control (MPDPC) strategies collectively named as model predictive direct control method (MPDCM) are developed for a grid-connected DFIG based WECS. MPDCM offers excellent performance in terms of torque, active, reactive and flux control, reduced ripples, improved power quality, reduced sensitivity to parameter variations and fast dynamic response. It also enables high-efficiency operation, improved fault ride-through capabilities, and enhanced grid integration. Detailed simulation and experimental tests are carried out to investigate the performance of the wind energy system MPDTC for two-level and three-level diode clamped rotor side converter fed DFIG based WECS. The performance of the DFIG at variable speed operations for both converter configurations is simulated in MATLAB/SIMULINK. Further the simulation study and experimentation are also carried to control active and reactive power for grid connected DFIG based WECS. Similarly, MPDPC has been implemented for two level voltage source inverter (VSI) and three level diode clamped grid side inverter. The experimental implementation for validation of simulation study of proposed MPDCM has been performed on a 5 KW slip ring induction motor by developing prototype model using WAVCET 300 R&D control board for two-level and three-level BTB converter at variable wind speeds. The results obtained shows the improvement in the overall performance of the DFIG with faster settling time and lower peak overshoot and undershoot for proposed model predictive direct methods. Through this comprehensive approach of development, simulation, and hardware validation, the study aims to contribute to the advancement of control strategies for DFIG-based wind energy systems. The goal is to enhance the system's efficiency, stability, and fault tolerance, promoting the reliable integration of wind energy into the power grid and supporting the transition to a sustainable and renewable energy future.