Rotor side control of grid-connected wound rotor induction machine

Abstract

This paper deals with modeling, simulation and implementation of rotor side control strategies for a grid connected wound rotor induction machine. In the system under consideration. the stator is directly connected to the constant frequency three-phase grid and the rotor is supplied by two back-to-back three-phase voltage source inventers with a common OC link. Such a configuration is attractive in large power applications with limited speed range of operation. The rotor currents are controlled at any desired phase frequency and magnitude to control the active and reactive powers or the machine independently. A stator flux-oriented model of the doubly fed wound rolor induction machine is presented. The current controllers are designed in the field coordinates. Simulation waveforms exhibit excellent transient response of the current loops; the dynamics or the direct and quadrature axes are also observed to be decoupled. An experimental setup consisting of IGBT inverters and a TMS320F240 DSP-based digital controller is developed in the laboratory to implement the control algorithms. Relevant experimental waveforms are presented they are observed to be in good agreement with the simulation results.