Backstepping Based Control for Fuel Cell Connected Grid System

Due to the reliability and the efficiency of the fuel cell, this energy source became a great research interest and a promising alternative of fossil sources. In fact, this paper focus on exceeding the fuel cell limits tied to the nonlinear characteristic P-I and the low supplied energy. For this reason, a double-stage converter is proposed in order to ensure the maximum power point tracking (MPPT) and to improve the energy provided by the fuel cell. The first stage is an interleaved boost that offers a high voltage gain, soft switching characteristics and reduced output ripple. Then, the second stage consists of a three-level boost converter with a reduced inductance and a switch voltage rating equal to half of the output voltage compared to the conventional boost converter. The boost stage is connected to half-bridge inverter and a T-LCL filter to adapt the FC energy and inject it into the electrical grid. Indeed, the contribution of this work is to invest the proposed converter to manage the power between the fuel cell generator and the electrical grid. Moreover, a non-linear controller based on the backstepping approach and the accurate model of the whole system, is developed despite the high order of the system. Meanwhile, an MPPT block is implemented to allow the operation of the fuel cell at its maximum power point in spite of the nonlinear characteristic. The efficiency of the controlled system is verified through numerical simulation carried out in Matlab Simulink environment.