Robust Single-Side-Current Damping Framework of High-Speed PMSM With Sine Wave Filter Based on Novel Duty-Cycle Updating Mechanism

In high-speed machine drives with sine wave filter, due to the synchronous transformation, the natural resonance in stationary coordinate will be converted into two resonances, which are located at f(res)-f(e) and f(res)+f(e) ( f(res) is the natural resonant frequency, and f(e) is the motor frequency). Theoretical analysis and experimental results suggest that traditional active damping (AD) methods with high-pass filter cannot effectively address the dual resonance issue within a specific frequency range due to digital control delay. To address this issue, this article proposes a robust single-side-current (SSC) damping framework with novel duty-cycle updating mechanism to minimize control delay. In this way, a simplified expression between the system parameters and the damping coefficients is discussed for both inverter-current feedback (ICF) and motor-current feedback (MCF) systems. Experimental results illustrate that the proposal is stable for LCL resonance within the Nyquist frequency, while exhibiting strong robustness against parameter variation.