Abstract: This paper develops a robust regulator design approach to maximum power point tracking (MPPT) of a variable-speed wind energy conversion system (WECS) under the concept of perturbation and observation. The proposed perturb and observe regulators (PORs) rooted on the sliding mode method employs the optimal power curve (OPC) to realize MPPT operations by continuously adjusting rotor spe...

By means of He's homotopy perturbation method (HPM) an approximate solution of velocity eld is derived for the ow in straight pipes of non-Newtonian uid obeying the Sisko model. The nonlinear equations governing the ow in pipe are for- mulated and analyzed, using homotopy perturbation method due to He. Furthermore, the obtained solutions for velocity eld is graphically sketched...

In this paper, an intelligent control strategy based on combination of the “flatness based control technique” and the “perturbation and observation (P&O) MPPT algorithm” is developed and investigated to control a hybrid electric energy source (HEPS). This EHPS is composed of a fuel cell system (FC) and a solar panel (SP), as the main source and a supercapacitor bank (SC), as the auxiliary sourc...

For studying the difference effect on the Cosmic Microwave Background Radiation (CMB) anisotropy spectrum by scalar and tensor perturbation, we define another function Alm, which can reflect the effect of different magnetic quantum number m. For a given l, we find that the ratio relations of Alm is different for the scalar perturbation sources and tensor perturbation sources. This give a new wa...

the current paper focuses on some analytical techniques to solve the non-linear duffing oscillator with large nonlinearity. four different methods have been applied for solution of the equation of motion; the variational iteration method, he’s parameter expanding method, parameterized perturbation method, and the homotopy perturbation method. the results reveal that approximation obtained by th...

The dynamical behaviour of the forced escape oscillator, which depends on the parameter values we considered, have been studied numerically using the techniques of phase portraits and Poincar'{e} sections. Also, we employed perturbation methods such as Lindstedt's method to obtain the frequency-amplitude relation of escape oscillator.