An Active Damping Control Method for Reduced DC-Link Capacitance IPMSM Drives

In order to mitigate harmonics of the grid input current, passive filters are applied widely in the power electric systems. The LC resonance and the negative input impedance are important concerns in the reduced dc-link capacitance motor drive system. In this paper, an active damping control method is proposed to suppress the LC resonance by the direct damping current approach, which can formulate the pole distribution of the drive system. Different control laws have been analyzed, and the stability analysis is evaluated by the Routh–Hurwitz criterion. Meanwhile, the active damping control method is realized by the voltage command, which can overcome the limited bandwidth of the current controller. Since the generation of the direct damping current only depends on the dc-link voltage, the proposed active damping control method is robust. Compared with the virtual impedance methods, parameters can be accurately optimized by Bode diagrams after adopting the proposed active damping method. Simulation and experimental results are provided to verify the effectiveness of the proposed method.