An Upconversion Management Circuit for Low-Frequency Vibrating Energy Harvesting

摘要

This paper proposes a high-efficiency small-size upconversion management circuit for low-frequency vibrating energy harvesting. Due to low vibrating frequency (32 Hz), the transformer of a traditional matching circuit has a large inductance (9171 H) and a large size $(> 50 times 50 times 50 hbox{mm}^{3})$. An upconversion matching circuit with a smaller inductance (25.3 H) and a smaller size $(< 20 times 20 times 20 hbox{mm}^{3})$ is developed. By using the smaller size upconversion matching circuit, higher charging power and ultimate charging voltage can be obtained at a higher frequency (3.28 kHz). The matching circuit can efficiently work at a wide vibrating frequency range. In order to drive the wireless sensor with a higher consumption power (110 mW), an instantaneous discharging circuit is developed that is suitable for weak vibrating energy harvesting (406 $ muhbox{W}$). The instantaneous discharging circuit can accumulate weak energy from the vibrating transducer during a long period, and it can provide a higher power output in a very short time. While the voltage across the storing capacitor is over 0.36 V, the instantaneous discharge circuit can drive a wireless sensor with an output power of 110 mW at a distance of over 80 m. The small-size high-efficiency upconversion management circuit can be used in many other low-frequency energy harvesters.