A hierarchical scheduling strategy for achieving multi-source energy complementarity in self-powered systems

Ensuring long-term, stable operation of self-powered systems considering the stochastic and fluctuating nature of ambient energy remains a pivotal challenge, as existing multi-source harvesting architectures are confined to static, non-responsive paradigms. This work presents a self-powered wireless sensing system that transitions the field toward automatic, priority-driven management through a hardware-enforced, quadruple-buffered power scheduling strategy. The core of this strategy is a scheduling protocol that orchestrates energy flow in the following order: real-time photovoltaic (PV) energy, PV-stored energy, real-time thermoelectric-vibration hybrid energy, and auxiliary-stored energy. This is implemented via a dedicated circuit that enables automatic stored energy release and seamless source switching (<20 ms). A critical enabling feature is the electrical isolation between the primary and auxiliary power paths, which prevents mutual interference and resolves the impedance mismatch inherent in conventional static topologies. Experimentally, the system achieves 93 min of operation from a 10-min charge under controlled conditions, surpassing standalone PV-only and thermoelectric-only systems by 47.6% and 116.3%, respectively. Its practical viability is demonstrated by 75 min of stable field operation and consistent performance over a 10-day continuous test, with an overall system efficiency of 75%. This work provides a robust, maintenance-free power solution, demonstrating significant potential for sustainable wireless sensing in intelligent transportation and broader Industrial Internet of Things applications.