DSP-based Control of Standalone PV/Battery Hybrid System

This paper investigates and presents the control and energy management of a typical standalone photovoltaic/battery hybrid system. The studied system in this paper includes two DC-DC converters. The first is a DC-DC boost converter works as a maximum power point tracker for the PV array, while the other is a bidirectional DC-DC converter used to regulate the DC bus voltage and to provide the necessary energy to the load by compensating the power deficit continuously. Generally, the developed control strategies in literature for such a system are based on proportional-integral (PI) controllers due to their simplicity of implementation, or by using some advanced nonlinear control concept, however this latter requires knowledge of system parameters and exact mathematical model for the design phase, which is sometimes difficult to obtain and makes the control technique sensitive to parameter variations. In order to overcome the previously mentioned drawbacks, this paper presents a model-free control technique based on a simplified version of fuzzy logic controller (FLC), this approach allows to keep the same implementation simplicity of PI controller and to considerably reduce the complexity of the conventional FLC. Experimental studies on a test bench were conducted to prove the effectiveness of the proposed approach.