Wound Rotor Induction Generator With Sensorless Control and Integrated Active Filter for Feeding Nonlinear Loads in a Stand-Alone Grid

This paper describes a vector control scheme for a stand-alone generator based on a wound rotor induction machine with rotor side control. The stand-alone generator refers to an isolated grid feeding a local load. The primary objective of the control scheme is to maintain constant voltage and frequency at the output of the generator irrespective of prime mover speed variation. A novel, simple, and easily implementable sensorless control scheme is proposed. The issue of power quality, which is one of the main concerns of a stand-alone generation system, is also addressed. This is done by incorporating the active filter concept in the control scheme to cancel significant harmonics. A method of unit vector generation for field-oriented control is proposed. A laboratory prototype consisting of back-to-back insulated-gate bipolar transistor converters and a TMS320F240 DSP controller is developed. Detailed experimental results are presented which demonstrate and validate the effectiveness of the proposed scheme.