Impedance Reshaping for Inherent Harmonics in PMSM Drives With Small DC-Link Capacitor

Abstract

Sharp LC resonance peak may enlarge inherent harmonics, dominant harmonics of the supply voltage generated by a three-phase diode rectifier, around the resonance frequency, which will intensify fluctuations of the DC-link voltage and grid currents in motor drives with small DC-link capacitor. In this paper, a novel resonance suppression strategy based on inherent harmonics impedance shaping is proposed specially for three-phase input PMSM drives with small DC-link capacitor. Instead of increasing the damping of the whole system for resonance suppression, the motor side power disturbance can be reduced by designing the impedance for inherent harmonics around LC resonance frequency, based on the new model with the consideration of motor side characteristic. For damping current generation, the angle of the virtual admittance is modified to eliminate the influence of the DC-link voltage sampling delay. Experimental results show the effectiveness of the method on a prototype of electrolytic capacitorless PMSM drive.

State-of-the-Art Grid Stability Improvement Techniques for Electric Vehicle Fast-Charging Stations for Future Outlooks

“…It ensured that reactive power flowed towards the grid in such a way that the amplitude of the reference current vector was adaptable to the FCS' power rating regardless of the grid condition [80,95]. Similarly, [86,89] presented the concept of virtually varying the effective line impedance at the harmonic frequency in such a way that the influence of mismatched line impedance on nonlinear FCS load distribution was reduced [96,97]. This strategy avoids losses, while mimicking the behavior of real impedance [87,88].…”