No abstract

In this paper, a variable gain super-twisting algorithm based on a barrier function is proposed for a class of first order disturbed systems with uncertain control coefficient and whose disturbances derivatives are bounded but they are unknown. The specific feature of this algorithm is that it can ensure the convergence of the output variable and maintain it in a predefined neighborhood of zero independent of the upper bound of the disturbances derivatives. Moreover, thanks to the structure of the barrier function, it forces the gain to decrease together with the output variable which yields the non-overestimation of the control gain.

No abstract

No abstract

No abstract

This study proposes a second-order sliding-mode observer (SOSMO) of the linear induction motor to deal with the sensorless problem, considering the influence of the end effects. The proposed SOSMO required only the measured voltages and currents to provide flux, motor speed and speed-depended parameter estimation simultaneously. The stability of the system and the error convergence of the flux and the speed have been proved. The performance of the proposed observer is verified by hardware-in-the-loop test system. Furthermore, a comparative study with model reference adaptive system and Luenberger observer is presented.

No abstract

This paper proposes a robust control strategy for a hybrid battery/super capacitors power system with a single converter. In such systems, it is required to smooth the battery current considering the load power transient and the current oscillations of the DC bus delivered by the load in the context of a hybrid electric vehicle. Furthermore, constraints of all the system components, i.e. maximum current of the battery and super capacitors, state of the charge of the super capacitors and battery temperature should be taken into account. To deal with these demands, a novel cascaded voltage control loop is proposed. For the outer voltage loop, an anti-windup proportional integral controller is used to regulate the super capacitor voltage at its nominal value. On the other hand, for the inner voltage loop, an anti-windup super twisting controller is proposed to ensure the convergence of the DC bus voltage to its reference value while attenuating the external perturbation. Indeed, the specific feature of such controller is that it works like a low-pass filter which leads to attenuate the current oscillations in the DC bus.