Stability Analysis of a Slip Power Recovery System under Open Loop and Field Orientation Control

Slip power recovery configuration provides an attractive alternative for variable speed drives and generating systems, due to its high-efficiency and low converter rating. The core component is the doubly-excited machine. Firstly, we present a stability analysis of the doubly-excited machine with open loop voltage and open loop current control in the rotor circuit. Possibilities of open loop control are analyzed. Secondly, we present a unified model of a high-performance slip power recovery system composing of a field-orientation controlled doublyexcited machine, power converters and a dc bus in the rotor circuit. Stability of this composite system represented by the model is studied. Of special interest is when the system functions as a variable-speed motor or as a variable-speed constant-frequency generating system.