Abstract
In the field of control, many approaches have been used to control generators, where indirect vector control (IVC) is considered one of the most prominent of these approaches due to its many advantages. This approach has a fast response time (RT) and is quite easy to realize. However, its reliance on traditional controllers makes this approach less efficient and less effective if the system parameters change. Consequently, this work proposes a new IVC approach for doubly-fed induction generators (DFIG) used in contra-rotating wind turbine (CRWT) systems. The designed IVC employs a super-twisting control to eliminate the instantaneous errors of the DFIG power using the direct calculation of the control voltage required by the rotor, which will lead to the improvement of the transient performance. In addition, a constant switching frequency is obtained using the multilevel fuzzy modified space vector modulation proposed for controlling the DFIG inverter, facilitating the design of harmonic AC filters. To evaluate the proposed solution, a digital simulation of the CRWT system was verified using MATLAB with the power of the used generator being 1.5 MW. For more accuracy, two tests were used to study the efficiency of the suggested control compared to the efficiency of the IVC in terms of getting better system features. The obtained results showed the efficacy of the designed control compared to the IVC and some of the different existing techniques in terms of enhancing system features. The suggested approach minimized torque fluctuations, active power, and current in the first test compared to the IVC approach by ratios estimated at 93%, 97%, and 98%, respectively. Also, the RT for reactive power, active power, and torque was reduced by 99.05%, 98.60%, and 98.60%, respectively, compared to the conventional IVC approach. In both tests, the designed approach minimized the harmonic distortion of the stream by ratios estimated at 18.02% and 16.22% compared to the conventional IVC approach. These obtained results were verified using empirical work, where hardware-in-the-loop simulation was used for this purpose. Accordingly, the empirical results demonstrated the validity, durability, and competence of the designed approach compared to the base IVC approach. Both the simulative and empirical results validate that the designed approach is of great importance in the field of control and renewable powers, as it can be relied upon to enhance the features of the systems. Therefore, the designed control has a promising future.