Model Analysis of Efficiency and Energy Distribution in the Powertrain of an Electric Vehicle Equipped with a Solar Cell Battery

This article presents an analysis of implementation of a solar cell system within an electric vehicle (EV), putting emphasis on the energy efficiency and control of energy flows. In the considered system topology, interaction between the low-voltage (LV) photovoltaic system (PV system) and the high-voltage (HV) traction system is organized through the energy medium in the form of a buffer battery. Both system structure and control algorithm were designed taking into account actual efficiency characteristics of involved components in order to attain maximum energy performance of the entire system. Efficiency analysis of the PV system components allowed substantiating an idea of using a LV buffer battery, as well as proposing PV array configuration preferable from the energy point of view. Analysis also allowed to draw the essential principles for elaboration of the control algorithm, which provides maximum efficiency of energy distribution in the PV system. The article gives a description of the mathematical model developed for analyzing system operation and dynamics of its key parameters. The model calculates vehicle dynamics and essential variables of the powertrain components (batteries, traction electric drive, voltage converters, and solar cells). Control algorithm regulating energy flows within the PV system was implemented as a part of said model. To simulate actual operating conditions of PV cells, a model of the solar irradiance (SI) was employed considering specified location, season, daytime, and weather (i.e., clouds). Simulations were performed taking into account typical operating regimes of the vehicle including different levels of the auxiliary power that feeds LV onboard consumers.