Showing papers by "Navid Reza Abjadi published in 2008"

Nonlinear sliding-mode control of a multi-motors web winding system without tension sensor

Abstract: In this paper, a sliding-mode (SM) feedback linearization control system is designed for a multi-motors web winding system. At the first, an ideal feedback linearization control system is adopted in order to decouple the tensions and velocity of the web winding system. Then to enhance the performance of the control system in the present of uncertainties, a SM feedback linearization control system is applied, that comprises a SM velocity controller and two SM tension controllers. In addition an open loop tensions observer is suggested and its stability is proved. Moreover the dynamics of the motors used in the web winding system is considered. Finally, the effectiveness and capability of the proposed control strategy is verified by computer simulation.

Nonlinear decoupled control for multi-motors web winding system using the sliding-mode technique

Abstract: In this paper a nonlinear decoupled control is designed for multi-motors Web winding system. At the first, an ideal feedback linearization control system is adopted in order to decouple the tensions and velocity of the Web winding system. Then to enhance the performance of the control system in the present of uncertainties, such as electrical and mechanical parameter variation, external disturbance and unmodelled system dynamics, a sliding-mode feedback linearization control system is applied, that comprises a sliding-mode (SM) velocity controller and two SM tension controllers. Finally, the effectiveness and capability of the proposed control strategy is verified by computer simulation.

Direct torque control of a two five-phase series connected Induction Machine drive using a three-level five-phase space vector PWM inverter

Abstract: This paper describes the decoupled torque and flux control of a two series connected five-phase induction machine (IM) drive that is supplied by a three-level five phase SVPWM inverter, using a well know phase transposition in the series connection. At the first, the decoupled torque and flux controller is developed based on variable-structure control (VSC). Then, a sliding-mode (SM) flux observer in employed to estimate the stator flux; that uses a two reference frames which result in eliminating the speed adaptation. Moreover simple control strategy is introduced for three-level SVPWM inverter that can be easily implemented in practice for a two-series five phase IM drive. Finally, the effectiveness and capability of the proposed control method is verified by computer simulation.

An Adaptive Nonlinear Controller for Speed Sensorless PMSM Taking the Iron Loss Resistance into Account (RESEARCH NOTE)

Abstract: In this paper, an adaptive nonlinear controller is designed for rotor Surface Permanent Magnet Synchronous Motor (SPMSM) drive on the basis of Input-Output Feedback Control (IOFC), and Recursive Least Square (RLS) method. The RLS estimator detects the motor electromechanical parameters, including the motor iron loss resistance online. Moreover, a Sliding-Mode (SM) observer is developed for online estimation of the rotor speed and rotor position. In this control scheme, the torque reference signal is generated by a conventional speed PI controller. The effectiveness and feasibility of the proposed control approach is tested by simulation. Computer simulation results show that the errors in the estimated quantities asymptotically converge to zero. These results also show that the drive system is stable and robust against the parameter uncertainties and external load torque disturbance.