MRAS state estimator for speed sensorless ISFOC induction motor drives with Luenberger load torque estimation

DTC based on SVM for induction motor sensorless drive with fuzzy sliding mode speed controller

“…Relative to the expressions that define the MRAS, the different models include integrators which create error in the estimation process caused by the unspecified original situation and estimate drift due to in the measured currents. To bypass the trouble, low-pass filters are used [20][21][22][23]. 175 Figure 5.…”

“…By substituting (17) into (20), the output of the speed controller based on sliding mode technique is represented by the electromagnetic torque * . The principle of the control law (SMC) for * can be divided into two parts: equivalent control which describe the action of the control used whenever the system is on the sliding mode and switching control which guarantees the existence requierement of the sliding mode.…”

“…Using (20) gives: To guarantee that (26) will stay negative, the value of the hitting control gain β has to be at the upper bound of the lumped ambiguity d(t), i.e.…”

“…Consequently, and in order to overcome the effect of any external perturbation, the hitting control gain β has to be selected big sufficiently [8,11]. Hence, the equation (20), that define the law to control speed, will ensure the entity of the switching surface s(t) in (18) and when the function e(t)of the error arrives at the sliding surface, the system will be supervised by equation (19) that is every time invariable [26]. Farthermore, the control system will be indifferent to Δa, Δb and the perturbation .…”

“…Farthermore, the control system will be indifferent to Δa, Δb and the perturbation . An application of the sign function in the sliding mode control (20) will generate fluctuations due to the discontinuous control action that generate trouble when the system approches thesurface of sliding [27]. To solve this phenomenon, Fuzzy logic combined with sliding mode is used.…”