A Comparative Study of DFOC and IFOC for IM Drive

This paper presents a comparative analysis of direct field-oriented control (DFOC) and indirect field-oriented control (IFOC). The speed control of IM drives is one of the challenging issues at low speed region, where the steady-state performance is the smoother but the dynamic response is poor. The vector control provides a smoother steady-state and transient response. In the vector control, the information of the rotor angle is essential. The rotor angle is measured from Hall sensors or by estimating with the adaptive scheme. But the installation of sensors in the machine shaft is complex and costly. The performance of DFOC and IFOC of IM fed with multi-level inverter is analyzed in the high speed and low speed operation respectively. The IFOC is suitable for low speed performance, while the DFOC for rated speed operation. The effectiveness of DFOC and IFOC is simulated using the MATLAB/Simulink environment.