Dynamic-performance comparison of IRFO and SFO-SM controlled drives in field-weakening region using variable-saturation regulators

This paper proposes to use variable-saturation regulators for induction motor drives operating in field-weakening region, and presents a comparative dynamic-performance analysis between the traditional indirect rotor field oriented (IRFO) control scheme and a new stator flux oriented - sliding mode (SFO-SM) control scheme. The traditional IRFO control scheme has the d-axis current component, torque, rotor flux, and speed loops with four PI-type controllers. The SFO-SM control system is a direct torque control - space vector modulation (DTC-SVM) scheme with closed loops of torque and stator flux without current PI-type controllers. Both control schemes use regulators with variable-saturation in such a way that maximum dc-bus voltage utilization is reached and overcurrent problems are prevented. The experiments are carried out using dSpace digital controllers and comparative results show that the SFO-SM controlled induction motor (IM) drive and IRFO one are characterized by similar dynamic responses in spite of structural simplicity of the SFO-SM control scheme