Slip-frequency controlled induction motor drives using digital phase-locked-loop control system

Current source inverter-fed induction motor drives (hereafter referred to as CSIM drives) have found wide application due to their reliable operation. They are unstable on open-loop operation over the normal speed-torque region. A step-by-step procedure is developed in this paper to fully model an angle controlled CSIM drive. The model includes such critical factors as commutation delay. The system equations are derived and cast in state-space form to employ advanced control techniques for the synthesis of stabilizers for CSIM drives.