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Akbarzade M.,Islamic Azad University at Quchan | Langari J.,Islamic Azad University at Quchan | Ganji D.D.,Nushirvani Technical University of Babol
Journal of Vibration and Acoustics, Transactions of the ASME | Year: 2011

In this paper, two novel and different methods are applied to nonlinear oscillators. It has been found that the coupled method of homotopy perturbation method and variational formulation and amplitude-frequency formulation work very well for the whole range of initial amplitudes. The analytical approximate frequency and the corresponding periodic solution are valid for small as well as large amplitudes of oscillation. Contrary to the conventional methods, only one iteration leads to high accuracy of the solutions. Some examples are given to illustrate the accuracy and effectiveness of these methods. © 2011 American Society of Mechanical Engineers. Source

Heydari F.,Nushirvani Technical University of Babol | Sheikholeslami A.,Nushirvani Technical University of Babol | Firouzjah K.G.,Nushirvani Technical University of Babol | Lesan S.,Nushirvani Technical University of Babol
World Journal of Modelling and Simulation | Year: 2010

This paper presents a new predictive current control (PCC) strategy using field oriented controller (FOC) for permanent magnet synchronous motor (PMSM). The suggested technique estimates the desirable electrical torque to track mechanical torque at a fixed speed operation of PMSM. The estimated torque is used to calculate the required current of motor based on conventional FOC technique. Finally, the duty cycle of the inverter is determined to feed the PMSM at a fixed switching frequency. The performance of the control schemes is evaluated in terms of torque and current ripple, and transient response to step variations of the torque command. Numerical simulations tests have been carried out to validate the proposed method in MATLAB. Source

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