A wireless sensor and energy harvesting system based on piezoelectric-electromagnetic synergy in P(VDF-TrFE) films

With the rapid growth in the number of Internet of Things (IoT) nodes, developing self-powered systems that combine high energy conversion efficiency with stable power supply capabilities has become a key challenge. To address the issues of narrow operating bandwidth, poor environmental adaptability, and limited output power in traditional single-mechanism energy harvesters, this paper proposes a piezoelectric, electromagnetic hybrid energy harvester (PEEH) based on a bidirectional magnetic excitation mechanism. Guided by the finite element method, the rotor’s magnetic circuit structure was optimized to create a periodically alternating bidirectional “push-pull” magnetic excitation. This effectively suppresses asymmetric oscillations in the cantilever beam, enabling stable harmonic motion and achieving efficient electromechanical coupling with a β-phase-rich poly(vinylidene fluoride-trifluoroethylene) thin film. Thanks to this synergistic design, the PEEH achieves an output voltage of 112 V at a wind speed of 12 m/s, and its total power reaches 38.5 mW at 17 m/s. By further integrating an adaptive under-voltage lockout power management circuit, a fully self-powered wireless monitoring system was developed that enables periodic Bluetooth data transmission even under intermittent wind conditions. This study demonstrates that synergistically enhancing piezoelectric and electromagnetic energy conversion through magnetic circuit optimization can effectively improve wind energy utilization efficiency and system power supply stability, providing an efficient, stable, and grid-independent self-powered solution for next-generation wireless IoT nodes.