Impedance Based Stabilization Control Method for Reduced DC-Link Capacitance IPMSM Drives

The instability issue is an important concern in the reduced dc-link capacitance motor drive system, which is caused by the interaction of the LC resonance and the negative impedance of the constant power load (CPL). Harmonics of the grid current also need to be concerned to meet the requirement of the application standards. In this paper, the impedance model of the drive system is established considering the dc-link voltage fluctuation, which is applied to evaluate the drive system stability. The grid current harmonics issue could also be analyzed by the grid input impedance model. A novel grid current feedback based stabilization control method is proposed to stabilize the drive system, which could formulate the Nyquist plot of the drive system. Besides, the grid current harmonics could also be suppressed effectively by adopting the proposed stabilization control method. Experimental results are performed to verify the effectiveness of the proposed method.