Sensorless control of wind SRG in dc microgrid application

This paper presents an innovative and effective control strategy of Switched Reluctance Generator (SRG), operating with Vujicic-Calasan PCT1 power converter in continuous-conduction mode (CCM), for a wind energy conversion system (WECS) employed in DC microgrids. The Vujicic-Calasan PCT1 power converter, whose validity in this paper is additionally confirmed through simulations and experimental results, is based on diode bridge rectifiers and does not contain switch components. Namely, it requires four diodes and one inductance filter per machine phases as well as one excitation voltage source. By regulating the dc excitation voltage the output power of SRG can be easily controlled. A procedure for determination of the optimal excitation voltage as a function of rotor speed, that provides maximal output power for defined RMS phase current and voltage is proposed. Moreover, the obtained optimal dependences are mathematically described to be used for control of SRG in WECS. In the simulations performed to study the proposed control strategy, a realistic wind profile is used, while the turbine operation with and without pitch controller is considered. Simulations results provided for the WECS confirm that the proposed control strategy ensures system stability and fast maximal power point tracking.