Low-Power Design of a Self-powered Piezoelectric Energy Harvesting System With Maximum Power Point Tracking

• Published in: IEEE transactions on power electronics 2012-05, Vol.27 (5), p.2298-2308
• Main Authors: NA KONG, HA, Dong Sam
• Format: Article
• Language: English
• Subjects: Applied sciences; Circuit properties; Control systems; Controllers; Convertors; Dynamical systems; Dynamics; Electric currents; Electric, optical and optoelectronic circuits; Electrical engineering. Electrical power engineering; Electrical equipment; Electrical machines; Electrical power engineering; Electronic circuits; Electronics; Energy; Energy harvesting; Energy. Thermal use of fuels; Exact sciences and technology; Frequencies; Generators; Harvesting; Impedance; Impedance matching; Maximum power; Miscellaneous; Modulation; piezoelectric transducers; Political power; power conditioning; power conversion; Power dissipation; Power networks and lines; pulse frequency modulation; Rational use of energy: conservation and recovery of energy; Signal convertors; Tracking; Vibrations; Wireless sensor networks
• ISSN: 0885-8993; 1941-0107
• DOI: 10.1109/TPEL.2011.2172960

A low-power energy harvesting system targeting to harvest several milliwatts from vibration is presented in this paper. Several low-power design schemes to reduce power dissipation of the proposed system are described, and sources of power loss are analyzed to improve the power efficiency. A discontinuous conduction mode (DCM) flyback converter with the constant on-time modulation is adopted for our system. The DCM operation of a flyback converter is chosen as for maximum power point tracking (MPPT) to be implemented with a single current sensor. The constant on-time modulation lowers the clock frequency of the controller by more than an order of magnitude for our system, which reduces the dynamic power dissipation of the controller. MPPT, executed by a microcontroller unit (MCU), is achieved through dynamic resistive matching, and the MPPT is executed at intermittent time intervals due to a relatively slow change of the operating condition. When MPPT is not active, the MCU operates at a lower clock frequency to save power. Experimental results indicate that the proposed system harvests up to 8.4 mW power under 0.5-g base acceleration with four parallel piezoelectric cantilevers and achieves 72% power efficiency around the resonant frequency of 47 Hz.