Hybrid Power Management System for LoRa Communication Using Renewable Energy

Energy management efficiency is a topical issue for Internet of Things (IoT) sensor networks because a sensor can be placed in harsh or hardly accessible places and must transmit data without maintenance. One characteristic of the LoRa technology is the high current peaks during the data transmission procedure. These current peaks can decrease the lifetime of the conventional power sources. Thus, to protect the conventional battery of the wireless sensor from degradation during fast discharging, a hybrid energy storage system can help. This article presents the design and development of a LoRaWAN sensor powered by a hybrid energy storage system and an energy management solution that can be integrated into the node. The novel solution presented integrates a 330-mW photovoltaic (PV) panel as a main source, a 4-F supercapacitor and a 230-mA small form factor Lithium battery as backup and it was tested in a real IoT application. Currently, as the most used solution to increase the battery lifetime of a LoRaWAN sensor is to reduce the communication time with the Gateway, our hybrid power management system comes with a solution for the node to be powered for a very long period of more than two years in worst case scenario configuration when the PV panel is not installed and more than ten years with hybrid power solution, without the compromise of reducing the communication time. The achieved communication distance is about 580 m with SF7 and more of 2 km with SF12 in an urban area.