Develop a Supercapacitor Real Time Model for PHIL Simulation

Abstract

Energy generation devices, like solar cells and fuel cells, can rarely meet all of the dynamic behavior of variable loads, which results in load performance limitations. Therefore, energy storage devices, like batteries and supercapacitors, are introduced into the system to ensure quality power is provided under a wide range of dynamic load conditions. Hardware-in-the-loop (HIL) and power-hardware-in-the-loop (PHIL) real time simulations are among the most reliable methods for ensuring generation and storage can meet load demands in real time, because it is executed physically rather than as a purely computational exercise. My research is focused on developing supercapacitor implementations for HIL and PHIL. For supercapacitors, equivalent circuit model can adequately represent the dynamic behavior, but this kind of model can be difficult to ascribe to physical meanings, which is significant for designing and scaling-up a commercial supercapacitor device. An expression-based equivalent circuit model is used to solve this problem. Parameters in the model can be linked with configuration parameters of an actual device. A Simulink model is then loaded in our OPAL-RT real time simulator, which together with power amplifier and programmable load, allow power hardware-in-the-loop real time supercapacitor discharge simulations. The PHIL results are shown to be limited by the ± 1 V and ±3 A hardware noise. To achieve higher voltages than allowed by a single cell, multiple cells get connected in series and parallel to achieve enough voltage and power. We show how a Simulink supercapacitor module can be built with passive balancing to achieve good module performance while limiting excessive potential on individual cells.