Discrete control by sliding mode of a photovoltaic system

This paper proposes a control strategy of a maximum power point tracking (MPPT) impedance adapter coupling a photovoltaic generator to a DC motor-pump. The proposed strategy is based on the sliding mode control theory of discrete systems permitting a direct control of power converter. The stability as well as the hardiness of the system is addressed, and a control diagram is presented. This work is motivated by the need to use the maximal power of PV generator, which is a special source of finished energy that has a non-linear current-tension characteristic (I/spl I.bar/V) dependent of temperature and solar irradiance. The PV generator price is even relatively high, so the user is interested to the optimal coupling of PV generator to electromechanical loads. In fact, this system used optimal coupling in order to have maximal power during the whole operating period (during the shining sun). Some reliable simulation results are provided in the following paper in order to demonstrate the efficiency of the proposed approach.