Intelligent resonance adaptation of piezoelectric beam harvesters for enhanced vibration energy conversion

Due to the need for sustainable and self-powered electronic systems, there is a growing interest in vibration-based piezoelectric energy harvesting. Traditional piezoelectric beam harvesters suffer from a limited resonant frequency range, and are also very frequency sensitive, which causes loss of voltage output, harvested power and conversion efficiency when operating outside of resonance. In this work, an adaptive resonance tuning solution for the cantilever piezoelectric beam harvesters for maximum energy harvesting under different vibration conditions is proposed. To continuously alter the resonant characteristics of the beam and keep it in resonance with the external vibrations, an adaptive tuning mechanism was designed, modeled, and simulated. Energy harvesting was optimized by modal analysis of the vibration mode. Adaptive and conventional configurations were compared and evaluated for their output voltage, harvested power, resonance-tracking accuracy, and conversion efficiency. The adaptive system resulted in up to 90% higher voltage output, a 71.5% conversion efficiency, and 100% harvested energy with controller errors under 1%, maintaining stable operation under varying conditions. The proposed approach can yield higher operating bandwidth, harvesting reliability, and energy conversion efficiency, which are suitable for applications such as self-powered sensors, wireless monitoring, and the Internet of Things.