Grid-Connected SRG Interfaced With Bidirectional DC-DC Converter in WECS

• Published in: IEEE transactions on energy conversion Vol. 36; no. 4; pp. 3261 - 3270
• Main Authors: dos Santos Neto, Pedro Jose, Barros, Tarcio Andre dos Santos, Catata, Elmer Hancco, Filho, Ernesto Ruppert
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.12.2021; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Data buses; DC-DC power converters; Distributed generation; Distributed system; Efficiency; Electric potential; Energy conversion; Excitation; Filtration; Generators; Hysteresis; interface converter; Parameters; Performance enhancement; Power generation; Ripples; Rotors; switched reluctance generators; Torque; Voltage; Voltage control; Voltage converters (DC to DC); wind energy; Wind power
• ISSN: 0885-8969; 1558-0059
• DOI: 10.1109/TEC.2021.3067500

This paper presents an interfaced wind energy conversion system (WECS) using the switched reluctance generator (SRG). A bidirectional DC-DC converter is adopted as an interface stage to achieve optimal excitation voltage at the SRG side, while a voltage source converter regulates the DC-bus voltage. The SRG works with superior performance, which is characterized by a compromise between efficiency and torque ripple, using the optimal excitation parameters. In addition, the interface stage adds a filtering behavior, mitigating the voltage ripple produced by the SRG, thus improving the power quality reflected in the grid current. A comparison of optimized SRG systems, with direct connection and with interfaced connection, is conducted. Experimental results show that the interface converter improves the performance of the SRG in WECS. Although the extra converter efficiency is approximately 88%, the overall system efficiency is only reduced by up to 2.5% due to the SRG optimal parameters. Nonetheless, as advantages of the method, the torque oscillations are reduced by up to 9.5% in high speeds. Moreover, due to the converter filtering behavior, the grid current harmonic content is reduced by up to 6% in the comparison. Therefore, this research indicates that the proposed approach is a viable option for SRG in WECS, especially for scenarios where the DC-DC converter is already necessary, such as in a microgrid application.