Title :
Improved sensorless direct torque control method using adaptive flux observer
Author :
Saberi, Hossein ; Sabahi, Mehran ; Sharifian, Mohammad B. B. ; Feyzi, Mohammadreza
Author_Institution :
Fac. of Electr. & Comput. Eng., Univ. of Tabriz, Tabriz, Iran
Abstract :
A simple structure and a quick and robust response of the direct torque control (DTC) makes it attractive in ac drives. However, in sensorless applications, a precise estimation of the rotor speed is a crucial issue as along with the torque and flux estimation. In this paper an adaptive flux observer is introduced with a stator current and flux vector components as state variables and rotor speed as an unknown parameter which is estimated by using an adaptive scheme. A non-linear inverter model is proposed to obtain a more accurate response. Also, torque, flux and current pulsations, during the steady-state conditions, are considered as the disadvantages of the classical DTC method. A combined DTC and space vector modulation strategy is presented by using fuzzy logic control (FLC). FLCs are designed to obtain a fast response in the transients, and a high accuracy during the steady-state conditions.
Keywords :
AC motor drives; fuzzy control; invertors; nonlinear systems; observers; parameter estimation; robust control; rotors; sensorless machine control; stators; torque control; DTC method; FLC; ac drives; adaptive flux observer; flux estimation; flux vector components; fuzzy logic control; improved sensorless direct torque control method; precise rotor speed estimation; sensorless applications; space vector modulation strategy; state model; stator current; steady-state conditions; torque estimation;
Journal_Title :
Power Electronics, IET
DOI :
10.1049/iet-pel.2013.0390