Field-Oriented Control of Energy-Regenerative Electromagnetic Slip Coupling

Electromagnetic slip coupling (EMSC), like other contactless transmission devices, has lots of advantages over contact transmissions such as clutch function, continuous speed regulation, and no mechanical wear. Nevertheless, the EMSC has inherent slip energy especially under the large-slip condition, which leads to low efficiency. A novel energy-regenerative EMSC was developed including wound-type EMSC and the energy-regenerative apparatus for slip energy recovery. To improve recovery efficiency of the EMSC, the field-oriented control strategy was proposed. In this case, the mathematical model of EMSC under synchronously rotating coordinate system was constructed and verified by experiment. Since direct-axis component and quadrature-axis component of current in three-phase windings of the EMSC are coupled, the feed forward decoupling control approach was employed. Space vector pulse width modulation technique was utilized to eliminate harmonic components of current in three-phase windings. Simulations and experiments were carried out to validate the proposed control strategy. The results showed that the voltage and current in three-phase windings were almost in-phase, the current only contained few of harmonic components, and slip energy of the EMSC decreased by 82.5%. In conclusion, the field-oriented control strategy is conducive to recycle the slip energy of the EMSC efficiently.