A Rectifier-Less Piezoelectric Energy-Harvesting Interface with a Sense & Track MPPT Achieving Single-Cycle Convergence and 568% Shock Power Improvement

The number of edge sensors for the Internet-of-Things (loT) has been increasing dramatically every year to feed servers and artificial intelligence (AI) with more and more data. While powering these edge devices with batteries becomes unrealistic, piezoelectric energy harvesting (PEH) provides a promising power solution when they are implemented in industry, machines, and infrastructures. In these application scenarios, there are two main types of kinetic energy: periodical vibrations with stable amplitudes and shocks with varying amplitudes. While most reported bias-flip rectifiers and associated maximum power point tracking (MPPT) techniques perform well under periodical vibration inputs [1]–[4] compared to other architectures [5]–[10], their performance decays sharply under shock conditions due to the insufficient impedance-matching speed to accommodate fast varying input amplitude [11]. To efficiently harvest energy from real-world environments where both periodical and shock excitations exist, this paper proposes a rectifier-less interface with a sense & track (SST) MPPT algorithm, which converges to a new maximum power point (MPP) in only one vibration cycle. This allows the PEH system to efficiently harvest kinetic energy from any form of vibrations with large and fast input amplitude variations.