Feedback Linearization Control Scheme for DFIG with DC-Based Converter System

Abstract

This paper proposes feedback linearization control (FBLC) scheme for the strongly-coupled DFIG with DC-based converter system which is applied in the VSC-HVDC power transmission system. This converter system consists of a stator side converter (SSC) and a rotor side converter (RSC). The stator and rotor of DFIG are connected to the DC-bus through SSC and RSC respectively. Since the voltages of rotor and stator are controlled by RSC and SSC simultaneously, the DC-based converter system is strongly coupled. Therefore, FBLC is adopted to control the strongly coupled system and linearize the system with full decoupling. FBLC controllers for RSC and SSC are designed to guarantee that DFIG operates at maximum power point (MPP) and stator flux keeps stable and the rotor current could track its reference closely and quickly in the stator flux-oriented frame. At last, the simulation is carried out. The results validate the feasibility of the proposed control scheme even if in the case of ramp-change wind speed.