This paper deals with modelling and control of an autonomous energy device used to automatize the 2ates of open channel irrigation systems. The conventional unidirectional boost converter is controlled to interface a photovoltaic module with a battery array and the electromechanical actuator of the gate, this allowing the operation of the system in the absence of solar irradiation. The work develops modelling of the proposed system in order to deduce a single controller regulating input voltage which is able to operate in the whole set of operation conditions of the system. The resulting system can be used to develop current or voltage outer controllers. Simulation results regarding response to different disturbances confirms its correct operation.