Mohammad Jannati

A new method for modeling and vector control of unbalanced induction motors

In general, rotating electrical machines can be modeled by an equivalent two phase machine. This means that an unbalanced 3-phase induction motor can be modeled by using an unbalanced two phase induction motor model. This paper shows this concept by modeling a faulty 3-phase induction motor in which one of its feeding phases is opened. The paper also presents a new fault-tolerant vector control (which is modified from the conventional vector control) that can be used to control a faulty three-phase induction motor. Simulation results show the good performance of the proposed method.

Modeling and vector control of unbalanced induction motors (faulty three phase or single phase induction motors)

All types of electrical machines can be modeled by an equivalent two phase machine. For example a balanced three phase induction motor can be modeled as an equivalent two phase induction motor (The dq Model). In the same way an unbalanced induction motor can be modeled as an unbalanced two phase induction motor. This paper shows this concept by modeling a faulty induction motor with one of its three feeding phases, open. Moreover the paper shows that the speed control of this faulty motor can be performed by a few modifications in the conventional vector control. This new vector control is suitable for unbalanced induction motors such as the single phase induction motor with unequal main and auxiliary windings. Computer simulation shows the good performance of the proposed method.

A new method for RFOC of Induction Motor under open-phase fault

From an energy conversion point of view, most of electrical machines including Induction Motors (IMs) can be modeled by an equivalent 2-phase machine model (d-q model). A 3-phase IM, with one of the phases opened (faulty 3-phase IM), can also be modeled by an equivalent 2-phase machine. If a conventional Rotor Field-Oriented Control (RFOC) for balanced IM is used for this faulty machine, considerable oscillations in the torque and speed will result. In this paper, a new technique for vector control of faulty 3-phase IM is presented. In the proposed method, the supposition of Lqs/Lds = (Mq/Md)2 = a2, which is normally applied in other FOC of unbalanced 2-phase IMs, is not used. Results showed that considerable improvements in the torque and speed responses are achieved, specifically in the reduction of the oscillations.

Using NSGA II multiobjective genetic algorithm for EKF-based estimation of speed and electrical torque in AC induction machines

High-performance AC drives require accurate speed and torque estimations to provide a proper system operation. The selection and quality of extended Kaiman fitter (EKF) covariance elements have a considerable bearing on the effectiveness of motor drive. Many EKF-based optimization techniques involve only a single objective for the optimal estimation of speed without giving concern to the torque. This paper presents a new methodology for the selection of EKF filters that uses non-dominated sorting genetic algorithm-II (NSGA-II) developed for filter element selection in order to investigate the concurrent optimization of speed and torque. The proposed optimizing technique for EKF-based estimation scheme is used in the combination with the sensorless direct torque control of induction motor. The multi-optimal based-EKF is tested with three regions of Pareto front curve.

A simple vector control technique for 3-phase induction motor under open-phase fault based on GA for tuning of speed PI controller

This paper discusses a simple vector control technique for vector control of faulty 3-phase Induction Motor (3-phase IM under open-phase fault) based on Rotor Flux-Oriented Control (RFOC). It is shown in the adapted system for vector control of the faulty IM, it is essential for the speed PI controller coefficients to modify. For this reason, Genetic Algorithm (GA) is employed for tuning of speed PI controller. The results of this study show that the proposed drive system have acceptable good speed and torque responses.

Modeling and RFOC of faulty three-phase IM using Extended Kalman Filter for rotor speed estimation

This research discusses d-q model and Rotor Flux-Oriented Control (RFOC) technique for faulty three-phase Induction Motor (three-phase IM when one of the stator phases is opened). In the controlling technique, two transformation matrixes are applied to the equations of faulty three-phase IM. As a result, the equations of faulty three-phase IM become similar to the balanced IM. Therefore, by employing some modifications in the conventional block diagram of the balanced IM, faulty motor control is possible. Additionally, for high performance vector control of the faulty IM, an Extended Kalman Filter (EKF) is used for motor speed estimation. Simulation results demonstrate the validity and applicability of this technique to improve performance of the faulty IM.

Rule-based supervisory control of split-parallel hybrid electric vehicle

Hybrid electric vehicles (HEVs) have been a hot topic of research over recent years due to their features whereby make them a feasible solution to tackle concerns regarding to global warming. HEVs powertrain control plays an important role to accomplish control objectives such as low emission and good vehicle performance. This paper presents a system-level simulation and rule-based supervisory control strategy of a Split-Parallel Hybrid electric vehicle (SPHEV) which can be regarded as Parallel-HEV powertrain family. Advance vehicle Simulator (ADVISOR) is used to determine the sizing and ratings of key components of SPHEV driveline to satisfy specific performance constraints. Then physical model of the vehicle of interest is developed and simulated in Matlab/Simscape environment. Subsequently, simulation results are presented and discussed in terms of their effectiveness and accuracy.

Fault-tolerant control of 3-phase IM drive (speed-sensor fault and open-phase fault)

In this paper, a fault-tolerant control strategy dedicated to star connected 3-phase Induction Motor (IM) is presented. The presented method is able to control 3-phase IM drive under healthy, speed-sensor fault and open-phase fault conditions. The proposed fault-tolerant control system is derived from an Extended Kalman Filter (to compensate speed-sensor fault) and two developed Field-Oriented Control (FOC) algorithms (to compensate open-phase fault). The performance demonstrated by the simulation results shows that, in comparison with conventional FOC, the proposed approach, provides an accurate vector control and good dynamic performance particularly in reduction of motor speed and torque oscillations.

Modeling of three-phase induction motor with two stator phases open-circuit

This paper presented a d-q model of a three-phase induction motor with two stator phases open-circuit (faulty three-phase induction motor). It is shown that with an appropriate transformation, the d-q model of faulty motor has the same structure of equation as a balanced three-phase induction motor. Based on the developed model of the faulty induction motor, simulations are carried out to study on the dynamic behavior of the faulty three-phase induction motor. The developed model for faulty 3-phase induction motor can be extremely useful in designing a controller for fault-tolerant drive system.

Modeling and speed estimation of a faulty 3-phase induction motor by using extended Kalman filter

This paper presents a modeling technique for a faulty 3-phase Induction Motor (3-phase Induction Motor IM under open-phase fault). The developed model has the same structure of equations as the balanced 3-phase model. It is shown that the model can be utilized to estimate the speed of a faulty IM based on an Extended Kalman Filter (EKF) estimation technique, which was developed for a balanced 3-phase IM. Simulation and experimental results are presented to show the validity of the proposed techniques.