Research Projects

Ever increasing penetration of power electronics converter based renewable energy sources causes various concerns on stability issues for power system. This is due to less inertia of these renewable sources unlike the synchronous generators. Traditional renewable energy sources are acting as a current source so as a grid following (GFL) inverters. In case of a microgrid, the local distributed energy sources need to supply the local load, even in case of a grid failure. But, these GFL inverters can’t act as a voltage source in case of a grid outage without shifting its control algorithm. From the existing research, it is evident that the grid forming (GFM) inverters have superior performance than the conventional GFL inverters in terms of voltage stability, frequency stability in case of weak grid conditions. The global share of wind energy penetration has increased enormously. So, these wind turbines need to support the grid like conventional synchronous generators. Doubly fed Induction Generators are crucial in the wind power generation, as the market share of this DFIG is more as compared to other. But, the disadvantages of this DFIG system is its brushes. So, in this project, the authors try to select brushless DFIG (BDFIG) for the implementation. This slow progress in the BDFIG is due to the fundamental differences in power flow characteristics and operating range between BDFMs and conventional singly-fed machines. Traditional design methods found in standard textbooks—typically based on a single air-gap volt-ampere rating applicable to conventional electrical machines, but not suitable for BDFMs. Consequently, most early proof-of-concept prototypes were developed by modifying standard IMs through stator rewinding and rotor replacement. Current research on BDFM design primarily focuses on the modulation type, due to the various harmonic-related challenges it presents, including torque ripple, time-harmonic distortions, iron saturation, core losses, vibration, and acoustic noise. So, the design of the BDFIG is considered in this project. The electromechanical motion equation was established in the control algorithm to emulate the inertial dynamics using grid forming based BDFIG. Due to the imitation of the operation features of synchronous generator, the BDFIG naturally provides the desired inertial response like synchronous generator. The inertial response may be achieved with the help of energy stored in the capacitors, small supercapacitors. But big energy storage is required for frequency regulation like a synchronous generator. However, integration of battery energy storage systems at grid level is very costly. This energy reserve can be achieved by operating wind turbine always at deloading point. So, the operating point can be shifted either to increase the power to the grid or to decrease the power to regulate the frequency. The investigation will be carried out in preparing resilient control algorithm for better seamless transition between grid connected and standalone modes of operation. This proposed work involves the development of an experimental setup for a grid-forming inverter-based Brushless Doubly-Fed Induction Generator (BDFIG) for Wind Energy Conversion System. The project seeks to address critical challenges in machine design, particularly those commonly faced by grid-forming (GFM) inverters, such as synchronization and current limiting. To overcome these issues, innovative control strategies will be implemented. Furthermore, a deloaded Maximum Power Point Tracking (DMPPT) approach will be incorporated to facilitate frequency regulation and inertia emulation, thereby enhancing the system’s overall stability and its ability to support the grid.