Influence of parameters detuning on induction motor NFO shaft-sensorless scheme

Abstract

In this paper, the parameter sensitivity analysis of shaft-sensorless induction motor drive with natural field orientation (NFO) scheme is performed. NFO scheme calculates rotor flux position using the rotor flux vector reference only, does not require significant processor power and therefore it is suitable for low cost shaft sensorless drives. This concept also eliminates the need for sensitive stator voltage vector integration and it is usable in low rotor speed range. However, low speeds are coupled with low stator voltage amplitudes, which inflate the NFO scheme sensitivity to an error in stator resistance parameter. Similar problems can also take place if mutual inductance parameter is detuned, but this time in whole speed range. This paper investigates the influence of each parameter error on the NFO control steady state characteristics and dynamic performance.

Keywords

• AC motor drives
• NFO
• stator resistance