Projeto de um conversor CC-CC de três portas não isolado: regulador de tensão com sistema de armazenamento de energia

Abstract

In the context of three-port DC-DC converters (TPC) applications, the use of these stands out as substitutes for conventional two-port converters. They are widely adopted in renewable energy systems due to their advantages, such as higher efficiency, reduced size, and lower cost. Additionally, these converters have the ability to operate in different modes, adapting to the specific needs of the system. This study focuses on the development of a prototype of the VR-BESS convertor (Voltage Regulator - Battery Energy Storage System), which is an example of a nonisolated TPC designed for renewable energy systems with battery storage. The main objective is to present the operation of this converter and describe the prototype development process. The development process consists of several stages. First, the design of the power and control module is carried out, where the system’s operating levels are established, the main involved quantities are calculated, and the values of the components necessary for the proper functioning of the converter are determined. Next, the design and assembly of the printed circuit board are carried out. Additionally, the necessary energy sources for the system’s operation are specified. This includes the photovoltaic emulation power source, responsible for providing primary energy, and the system’s batteries, which store excess energy. After that, the programming of the DSP (Digital Signal Processor) is carried out, and the gains of the voltage and current sensors used in the prototype are measured. Finally, the performance validation of the converter is carried out through simulations and practical tests, demonstrating its ability to regulate voltage at the load and manage the charging and discharging currents of the batteries. Additionally, practical results show an average efficiency of 87.4% when the VR-BESS converter operates with a power range of 360 to 550 W delivered to the load in each operating mode. As limitations, it is noted that efficiency is compromised due to the high values of the MOSFETs’ (Rdson) resistance and also due to low heat dissipation.