H∞ control of DC-DC converters with saturated inputs

A consistent framework for robust control of power converters subject to saturated inputs is presented. Usually, linear control design methods do not take into account the effects of duty-cycle saturations, which can lead to degradation of performance and even to destabilization of the converter. An illustrative example of this problem is presented and a possible solution is proposed. Such solution consists of a saturation model based on a deadzone nonlinearity and a controller design method based on a sector condition expressed in LMI form. The objective of the proposed design method is to maximize the region of stability of the closed-loop saturated system. The method has been verified with numerical simulations and it has been compared with the conventional results of the controller design method that does not consider the input saturations.