Contribution to Improve the Direct Torque Control in the Photovoltaic Pumping System

摘要

The paper is intended to present a method to achieve better control and optimization between the different functions of the elements of a photovoltaic pumping system. The photovoltaic panel can provide a maximum power only for defined output voltage and current. In addition, the operation to get the maximum power depends on the terminals of load, mostly a non-linear load like induction motor. We inserted an intelligent control method in the photovoltaic system. It can be used to maintain the operation of the photovoltaic panel at maximum power under variable temperature and irradiance conditions. This can be done by means of the Maximum Power Point tracking by controlling the voltage or current generator independently of the load. Firstly, the system was tested with the use of Scalar-Based methods, as the Voltage/frequency control, calculated PWM technique. However, we cannot maintain the speed optimal. Finally, we used Vector-Based methods. We have chosen the Direct Torque Control using a Controlled Space Vector Modulation. This method allows reducing ripple of the electromagnetic torque and the stator flux, it improves the stator current signal.