PROJECT TITLE :

Research of Voltage Amplitude Fluctuation and Compensation for Wound Rotor Brushless Doubly-Fed Machine

ABSTRACT:

This paper presents an sudden fluctuation of voltage for a thirty-kW wound rotor brushless doubly-fed machine (BDFM) during a standalone power generation system. To address this issue, an improved methodology of harmonic injection is introduced. A voltage and current double closed-loop control strategy, primarily based on control winding (CW) current decoupling, is applied through the entire experiment. Consequently, the experimental outcomes are fairly aligned with the dynamic simulations in most conditions. However, the voltage fluctuation in the power winding (PW) can be observed for a certain speed vary. Harmonic analysis is then dispensed on experimental knowledge of PW voltage and CW current. A combine of interharmonic waves, that are symmetric with respect to the elemental wave, is demonstrated to exist in PW voltage and CW current. Thanks to the analysis, these harmonic conjugate waves are caused by the high-order magnetomotive force tooth harmonics and current harmonics within a particular speed range. Accordingly, the management strategy of harmonic injection is employed to effectively eliminate these harmonic conjugate waves. The experimental results additional highlight that the voltage amplitude will be maintained with less harmonic contents by our tailored control theme. Moreover, the formation and presence of harmonic conjugate waves may lead to the voltage amplitude fluctuation of BDFM within the standalone power generation system.