Self-sensed, self-adapted and self-powered piezoelectric generator architecture by synchronous circuits of autonomous parameter tuning

Synchronous circuits are effective to enhance the performance of piezoelectric generators and further show the capability of extending the generator's bandwidth by tuning the switching parameters due to the electromechanical coupling effect. However, many studies are limited to theoretical investigations or restricted experimental conditions with externally powered controllers. Besides, a critical and unsolved challenge for the circuit controller is the sensing of the generator's dynamics for the tuning of the operation parameters of the synchronous circuits since the switching timing cannot be ensured for varied generator dynamics due to the electromechanical effect of the tunable circuit. This paper presents a new self-powered autonomous piezoelectric energy harvesting system with an integrated structural and electrical design, including a dedicated self-sensed generator and a self-adaptive synchronous interface circuit. The system can automatically tune the extraction parameters (the switching phase and the voltage flip ratio) according to the self-sensed information by utilization of a precise maximum power tracking strategy for optimized power and bandwidth. Compared to the system with the classical synchronous circuit, the proposed design demonstrates superior power harvesting capabilities (0.7125mW@0.05 g), extended bandwidth (2.5 Hz, 471 % of the conventional approach) and excellent adaptability (a tunable and self-sufficient frequency range of 10.6 Hz at 0.1 g acceleration).