Optimization of the Hybrid Energy System Dedicated to Internet of Things Devices

The energy autonomy of electronic devices used in embedded systems and by the Internet of Things determines the efficiency of these systems. This article highlights the design of a hybrid power source combining a piezoelectric energy harvester and an electromagnetic energy harvester to improve this autonomy. Simulations performed using COMSOL Multiphysics 6.2 showed the possibility of producing an output power of 4.35 mW at a resonant frequency of 46.5 Hz. This represents a significant improvement of 74% compared to the piezoelectric-only system (2.50 mW) and 135% compared to the electromagnetic-only system (1.85 mW). The hybrid system demonstrates a bandwidth of 9 Hz and a quality factor of 5.2. Parallel coupling was found to be significantly more effective than series coupling in maximizing vibrational energy recovery, demonstrating its superiority for this application. Although the hybrid system presents a trade-off between power output and bandwidth, it offers the highest energy efficiency for stable-frequency applications. According to these analyses, this optimized hybrid energy harvesting system offers several advantages over electrochemical batteries for powering low-consumption electronic devices, making them autonomous.