I. Introduction
This paper develops a hardware-in-the-loop (HIL) setup capable of experimentally emulating the coupling between electrochemical batteries and photovoltaic (PV) arrays in real time. The current work is motivated by earlier research that shows that certain PV-battery integration topologies exhibit self-balancing behavior, meaning that differences in state of charge (SOC) between battery cells diminish with time without the need for active balancing circuitry [1], [2]. The benefits of such self-balancing behavior are (i) a significant reduction in the power electronics for battery management, as well as (ii) the cost, complexity and bandwidth requirement for achieving PV maximum power point tracking (MPPT) [3], [4]. However, there is a need for a flexible setup for demonstrating these benefits in the laboratory. This paper develops a real time HIL setup that can emulate PV arrays of different power ratings under various environmental conditions. The power generated by these simulated PV arrays is applied to physical battery cells together with a customizable load profile applied to the overall PV-battery system. Thus, the overarching objectives of this paper are to: (i) develop a HIL setup that is flexible enough to emulate new PV-battery integration topologies and (ii) perform system-specific experimental studies for design and controller development.