Dynamic Performance Comparison of IRFO and SFO-SM Controlled Drives in Field-Weakening Region Using Variable-Saturation Regulators

Abstract

This paper proposes to use variable-saturation regulators for Induction Motor (IM) 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 IM drive and IRFO one are characterized by similar dynamic responses in spite of structural simplicity of the SFO-SM control scheme.