Feature Extraction of Frequency-Mapping-Based Resonance Suppression in PMSM Drives With Low DC-Link Capacitance and Inductance

For the electrolytic capacitorless permanent magnet synchronous motor drives with low dc-link inductance, the increase of the resonant frequency and the complex coupling between the grid- and dc-side currents result in the performance reduction of the active damping method. This article proposes a suppression strategy based on the feature extraction of the grid current harmonics from frequency mapping. With the high-to-low frequency mapping, the low-frequency feature signals of grid current harmonics are applied to characterize the high-frequency resonance, which reduce the sampling and update errors caused by the higher resonant frequency. On the basis, the closed-loop control of the low-frequency feature signal is adopted to reshape the impedance relationship between the grid current and rectified voltage. Therefore, the harmonics of the grid current can be decoupled from the dc-side current, and the high-frequency resonance of the grid current can be directly controlled, which realizes resonance suppression in the low dc-link inductance drives. Experimental results verify the effectiveness of the proposed suppression strategy.