Real time implementation of indirect rotor flux oriented control of a five-phase induction motor with novel rotor resistance adaption using sliding mode observer

High performance multiphase motor drive requires precise knowledge of the state quantities and the machine parameters. Access to these state quantities is through measurement using sensors whose accuracy is paramount to achieve the performance level required by industrial applications. However, the problems of the parameters variations, inaccessibility to the measurement of some states, no-observability of the machine in some regions, the cost of the sensors and their lack of precision, make this very difficult task. To address these problems, it is necessary to resort to soft sensors through the design of observers and estimators. In multiphase induction motor drive, the observation problem arises especially for rotor flux that is not accessible for measurement. About the parameters variations, the rotor resistance and the stator resistance are the most critical parameters of the machine because their influence is crucial for the control and observation. The change in the resistances can be as large as 40-50% of the rated value, which may affect the control adversely. This paper develops a new structure of an adaptive sliding mode observer based on an online estimation of the rotor resistance value in order to avoid the effect of its variation in the rotor flux oriented control. The results show convergent (the errors in the transient and steady states are 5% and 1%, respectively) behavior of the drive using the proposed control scheme for large rotor resistance variation under loaded condition. The stability of the drive is proved using Lyapunov criteria. The simulation results are validated using real time implementation. - 2018Scopu

Adaptive direct torque control using Luenberger-sliding mode observer for online stator resistance estimation for five-phase induction motor drives

Direct torque control is considered as one of the variable structure control techniques which are characterized by fast response, simplicity and provide direct control of both electromagnetic torque and stator flux by adequate selection of the inverter switches in each sampling period. In case of multiphase motor drives, the increase in voltage vectors offers flexibility to optimize the selection of the inverter switching states, thereby achieving more precise control of the torque and flux. Nevertheless, the criterion for the selection of the inverter states becomes more complex. This aspect is not considered an issue in the traditional three-phase motor drives but needs to be considered in designing the switching table of the direct torque control of five-phase induction motor. Due to the auxiliary vector plane, the low-frequency harmonics need to be eliminated and full utilization of the dc link voltage is desired. The effects of parameter variation (particularly, stator resistance) on the performance of the direct torque control. It is necessary the addition of parameter adaptation algorithm to compensate this effects. A novel direct torque control of five-phase induction motor using a new switching table combined with an adaptive variable structure observer to avoid the effects of stator resistance variations is presented in this paper. Simulation results provided show the effectiveness of the proposed control strategy

Online Adaptation of Rotor Resistance based on Sliding Mode Observer with Backstepping Control of A Five-Phase Induction Motor Drives

Multiphase electric drives have been developed due to numerous advantages offered by those machines when it compared with the conventional three-phase machines. Multiphase motor drives are considered for applications, where the reduction of power per phase for both motor and inverter and high reliability are required. High performance control techniques are developed for multi-phase drives. The performances of the high performance controller and flux observers may be degraded during the operation. Since the parameters of Induction Motor (IM) varies continuously due to temperature variation and heating. Thus it is significantly important that the value of rotor resistance is continuously observed online and adapted by the control algorithm in order to avoid detuning effects. The efficiency and performance of an induction motor drive system can be improved by online observation of the critical parameters, such as the rotor resistance and stator resistance. Among the parameters of IM, rotor resistance is a decisive one for flux estimation, and also the stator resistance becomes critical in the low-speed operation condition. This paper presents a new online estimation method for the rotor resistance of the IM for sliding mode observer. This method generally based on theories of variable structure and is useful in order to adjust online unknown parameters (load torque and rotor resistance). The presented non-linear compensator afford a voltage inputs on the articulation of stator current and rotor speed measurements, and engender an estimates for the unknown parameters simultaneously, the non-measurable state variables (rotor flux and derivatives of the stator current and voltage) that converge to the corresponding true values. Under the persistent excitation condition, the proposed method estimates the actual value of rotor resistance, which guarantees the exact estimation of the rotor flux. Non-linear Backstepping control and adaptive sliding mode observer of a five-phase induction motor drive is presented. The accuracy and validity of the method is verified by MATLAB simulation model

Torque ripples improvement of direct torque controlled five-phase induction motor drive using backstepping control

The paper proposes Direct Torque Control (DTC) of a five-phase induction motor drive with reduced torque ripple. The method presented here is the DTC-Backstepping based on the classic DTC working with a constant switching frequency of the inverter. Another remarkable aspect is the complexity of the method proposed, both in the control unit of the inverter and in the number of correctors necessary for the control of the torque. The selection table and hysteresis have been eliminated. This method significantly improves the torque and flux oscillations and improves the dynamics of the drive by making it less sensitive to load torque disturbances. The proposed method is developed and designed using Matlab/SIMULINK to show the effectiveness and performances of the DTC-Backstepping.Atif Iqbal (S-04 M-09) received the B.Sc. and M.Sc.Engineering (Electrical) degrees from Aligarh Muslim University (AMU), Aligarh, India, in 1991 and 1996, respectively, and the Ph.D. degree from Liverpool John Moores University (LJMU), Liverpool, U.K., in 2006. From 1991, he was with the Department of Electrical Engineering, AMU, where he was a Lecturer and a Reader. He is currently with the Electrical and Computer Engineering Program at Texas A M University at Qatar, Doha, Qatar. His current research interests include power electronics and multiphase motor drives. Dr. Iqbal is a recipient of the Maulana Tufail Ahmad Gold Medal for standing first in B.Sc. Eng. exams in 1991, and the AMU and the Engineering and Physical Sciences Research Council (EPSRC), Govt. of U.K. Fellowship for pursuing the Ph.D. degree at LJMU.Scopu

Online adaptation of rotor resistance based on sliding mode observer kwith backstepping control of a five-phase induction motor drives

Multiphase electric drives have been developed due to numerous advantages offered by those machines when it compared with the conventional three-phase machines. Multiphase motor drives are considered for applications, where the reduction of power per phase for both motor and inverter and high reliability are required. High performance control techniques are developed for multi-phase drives. The performances of the high performance controller and flux observers may be degraded during the operation. Since the parameters of Induction Motor (IM) varies continuously due to temperature variation and heating.Thus it is significantly important that the value of rotor resistance is continuously observed online and adapted by the control algorithm in order to avoid detuning effects. The efficiency and performance of an induction motor drive system can be improved by online observation of the critical parameters, such as the rotor resistance and stator resistance. Among the parameters of IM, rotor resistance is a decisive one for flux estimation, and also the stator resistance becomescritical in the low-speed operation condition. This paper presents a new online estimation method for the rotor resistance of the IM for sliding mode observer. This method generally based on theoriesof variable structure and is useful in order to adjust online unknown parameters (load torque and rotor resistance). The presented non-linear compensator afford a voltage inputs on the articulation of stator current and rotor speed measurements, and engender an estimates for the unknown parameters simultaneously, the non-measurable state variables (rotor flux and derivatives of the stator current and voltage) that converge to the corresponding true values. Under the persistent excitation condition, the proposed method estimates the actual value of rotor resistance, which guarantees the exact estimation of the rotor flux. Non-linear Backstepping control and adaptive sliding mode observer of a five-phase induction motor drive is presented. The accuracy and validity of the method is verified by MATLAB simulation model. 2016 Institute of Advanced Engineering and Science. All rights reserved.Scopu

A novel DTC scheme for a sensorless five-phase IM drive under open-phase fault

Purpose: This paper aims to deal with direct torque controller when the five-phase induction motor drive in faulty operation. Precisely, open-phase fault condition is contemplated. Also, the DTC is combined with a speed-adaptive variable-structure observer based on sliding mode observer. Design methodology/approach: Two novel features are presented. First, the concept of the virtual voltage vector is presented, which eliminates low-frequency harmonic currents and simplifies analysis. Second, speed information is introduced into the selection of the inverter states. Findings: Direct torque control (DTC) is largely used in traditional three-phase drives as a backup to rotor-stator flux-oriented methods. The classic DTC strategy was primarily designed on the base of hysteresis controllers to control two independent variables (speed, torque and flux). Due to the additional degrees of freedom offered by multiphase machine, extensive works have been extended on the ensemble five-phase drives in healthy operation. In addition, the ability to continue the operation in faulty conditions is considering one of the main advantages of multiphase machines. One can find in the literature different approaches treating this subject. The applicability of DTC after the appearing of a fault has not been enclosed in the literature. Originality/value: Theoretical development is presented in details followed by simulation results using Matlab/Simulink to analyze the performance of the drive, comparing with the behavior during healthy situation.Aligarh Muslim University, Engineering and Physical Sciences Research CouncilScopu

Second-order sliding mode for marine current turbine fault-tolerant control

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