MATHEMATICAL MODELLING, DESIGN AND STABILITY ANALYSIS OF SI SIDO BOOST CONVERTER FOR PHOTOVOLTAIC APPLICATIONS

Abstract

This project describes the design of a model and controller to operate a SIDO (single inductor, dual output) DC-DC boost converter powered by solar PV. The SIDO converter uses a single inductor to produce output from one input source, which minimizes the number of components used compared to using two converters. Solar PV installations experience limitations, such as variable solar irradiance (sunlight intensity) and conditions of partial shading/temperature, resulting in irreconcilable variations of MPP for a given period of time. Therefore, in order to continuously extract the maximum power available from a solar PV array at any time, the proposed project uses an MPPT algorithm. The mathematical model of the SIDO converter utilizes linearization through state space averaging techniques and small signal approximation techniques to determine the best combination of input/output using an Interaction Measure (RGA). This enables the implementation of a decentralized PI control scheme for both outputs using internal control of the two outputs, while minimizing the amount of cross-regulation that occurs . Under normal operating conditions and also when using partial shading. The output voltage was shown to be consistent, with an output voltage of approximately 410V and 450 for the two models, at a light level of 1000 W/m². Round Model 1 produced about 600 W more than Round Model 2 when comparing the power produced, while at the same time increasing the overall efficiency of the power produced. The results of this project show the effectiveness of controlling the SIDO topology of the Decentralized PI Control using the RGA as the most appropriate method for interfacing renewable energy sources.