Active Damping Control Methods for Three-Phase Slim DC-link Drive System - An Overview and Investigation

In the conventional variable speed drive, the dc-link including the dc-choke and electrolytic capacitor is bulky with limited lifetime. The slim dc-link drive is thus proposed for the lower cost and longer lifetime by using the film capacitor to replace the electrolytic capacitor and dc-choke. However, such drive system suffers from the potential instability issue, due to the negative incremental impedance characteristic caused by the constant power load behavior of the motor drive system, and the influence by the reduced capacitance. Therefore, active damping methods are very important for stabilizing such slim dc-link drives together with the benefit of low cost and high flexibility. This paper gives an overview of the state-of-the-art active damping methods for the three-phase slim dc-link drive. The main pros and cons of each method are identified. The theoretical comparison is validated through the simulation and experimental results.