Converter design for solar powered outdoor mobile robot

Abstract

This project presents a hybrid system implementing the use of solar panels and batteries to power a robot. The main aim is to integrate a charging system which allows the batteries to be charged from solar panels, wall outlet, and a deployable solar charging station. The proposed system is divided in three sections: design of solar panels, design of a battery charger and design of a DC-DC converter with fuzzy MPPT tracking system. This paper will cover only up to the design of the DC-DC converter, as further work is still pending design/results. For the design of the solar panels, different cell configurations were considered. Once the solar panels were designed and fitted to the robot, we determined the battery requirements to meet the robot power load and payload. Lithium Polymer batteries were chosen as the power source for the robot since they have a competitive power density to weight ratio. In order to extend the battery life, and simplify the load, we decided to take two battery banks. One battery is charging while the other battery is discharging. This allowed us to precisely control the battery charging profile without load variations interfering with our measurements. We used a fuzzy maximum power point tracking controller with a primary focus on regulating the power input for a lipo. Different topologies of DC-DC converters were considered and based on our literature research, it was concluded that a Buck-Boost converter is the most appropriate option when working with solar cells. The following paper discusses all the design specifications, component decisions and construction of the solar powered robot. Various technologies, not used in the robot, are included here as a literature review of the current state of the art. The goal of this paper is to summarize the tested methods and results to expedite future researchers in the correct direction.