PORTABLE LITHIUM-ION BATTERY UPS WITH BMS FUNCTION FOR RASPBERRY PI AND OTHER IOT EMBEDDED SYSTEMS

Abstract

The increasing number of IoT (Internet of Things) based embedded systems, used nowadays in every aspects of our lives, inherently generates new challenges that require specific technical attention regarding: the increasing power demand directly proportional with the rising of their computational power and wireless communication functions, a more complex and flexible UPS (Uninterruptible Power Supply) design with load sharing function, a correctly balanced BMS (Battery Management System) consistent with the battery technology used and the manufacturer technical specifications, a more stable DC to DC converter output, a smarter system fail-safe algorithm, all concentrated in a more compact form factor. Taking all that into consideration, this article addresses all the previously mentioned issues in order to design, evaluate and present a fully functional UPS prototype for most IoT embedded systems. Although the proposed UPS prototype design can also be successfully used on non-OS (Operating System) IoT embedded platforms, with minor adaptations, the focus experimentation in this article will be on the every student’s favorite, but power demanding, Raspberry Pi 4 Model B. Basically, being a complete and miniaturized OS computer, the popular Raspberry Pi 4 is a very adamant candidate for tight input DC power parameters, that work in direct correlation with the system’s stability and performance. The final goal of the proposed UPS prototype is to provide Raspberry Pi 4 with enough independent runtime, until it safely shuts down the OS, in case of an external power blackout, and start back on at an external power restore event, all in order to protect the file system stability, or the data acquisition and storage processes from corruption.