Mehdi Tavan

Mehdi Tavan, Kamel Sabahi

It is well-known that measuring the input voltage and current, as the feedforward and feedback terms, are vital for the controller design in the problem of power factor compensation of an AC-DC boost converter. Traditional adaptive scenarios correspond to the simultaneous estimation of these variables are failed because the system dynamics is not in the classical adaptive form. In this paper, the system dynamics is immersed to a proper form by a new filtered transformation to overcome the obstacle. The phase and amplitude of the input voltage along with the input current is estimated from the output voltage with global convergent. An application of the proposed estimator is presented in conjunction with a well-known dynamic controller. The estimator and controller performances are evaluated by some realistic simulations.

Mehdi Tavan, Kamel Sabahi, Saeid Hoseinzadeh

This paper addresses the problem of state and parameter estimation for a class of second-order systems with single output. A new filtered transformation is proposed for the system via dynamic vector and matrix. In this method, the dynamics of the vector and matrix are derived by immersion and invariance technique such that the state estimation condition is guaranteed. Compared to the classical approaches that persistency of excitation (PE) condition is required for parameter convergence, the proposed method needs a weaker one, so called non-square-integrability condition, in the transformation via dynamic matrix. Simulation results are concluded for a class of regressors which are not PE but satisfy the new condition.

Mehdi Tavan, Kamel Sabahi

Input current estimation is indispensable in the sensorless control algorithms for the problem of power factor compensation (PFC) of an AC-DC boost converter. The system estimator design is challenged by the bilinear form dynamics and uncertain parameters of the system. In this paper, the system dynamics is immersed to a proper form by a new filtered transformation. Thanks to the proposed transformation, the input current, input voltage amplitude, and load conductance are globally estimated. The exponential convergent of the estimates is established in normal converter operation. An application of the proposed estimator is presented in conjunction with a well-known dynamic controller.