Hee-Sung Lim, Seok-Kyoon Kim, and Kyo-Beum Lee, "Model-Free PZC Filter-Based Multi-Loop Speed Controller for Servo Drives via Active Damping Injection Approach," Journal of Power Electronics, in press. -SCIE > Paper

This study devises an advanced multi-loop speed feedback system equipped with model-free pole-zero cancellation (PZC) filters for the position and 

current measurements of servo drives. The proposed feedback system does not necessitate an the exact system model and renders the transfer 

function of each loop in a first order low-pass filter form by involving the active damping terms. Furthermore, the PZC filters output the desired speed 

and current information for each loop along the first order convergent system,independent of the system model. An experimental platform involving a 

500 W brushless DC motor, with a digital signal processor as the controller, validates the practical improvement of the proposed feedback system.