DC-Bus Voltage Controller Design for an SCIG using Root-locus with System Parameter Change Immunity

A squirrel cage induction generator (SCIG) system experiences the change of parameters due to variation in temperature, change of load demand, or minute variations in mechanical fabrication. Therefore, a conventional PI controller for DC-bus voltage with active front-end rectifier (AFE) is subjected to controller’s parameter tuning with system aging and load change. In this paper, a DC bus voltage control technique is realized utilizing root-locus based pole-zero placement technique. This DC-bus controller places poles and zeros at a desired location of the system root-locus, which gives the benefit of parameter invariant response. This mathematical analysis of voltage control technique and its implementation is explained in detail for SCIG. The voltage controller follows the conventional current controller design for an indirect field-oriented power control (FoPC) for a fixed speed SCIG. The overall control is investigated and tested in PLECs simulation platform, and the results are presented for various load dynamics operations.