An energy management strategy integrating high-efficiency voltage regulation and charge protection for ambient energy harvesting system

Abstract

Micro-energy harvesting technologies are expected to replace traditional chemical batteries, providing stable and continuous clean energy for low-power wireless sensors. However, the voltage generated by micro-energy harvesting systems is often irregular and chaotic, making it unsuitable for direct use in electronic devices. To address this issue, this paper proposes an adaptive duty cycle interface circuit based on the Perturb and Observe (P&O) method, aiming to reduce the fluctuation of the output voltage while also implementing charging and discharging protection control for the battery. Experimental data have verified the feasibility of the voltage regulation strategy proposed in this paper, when the input voltage is constant and the target output voltage varies within the range of 1.2 V–4.2 V, the output voltage fluctuation of the P&O-based adaptive duty cycle control strategy is limited to 0.034 V. Moreover, when the input voltage is between 1 and 50 V, the maximum fluctuation of the output voltage is 0.344 V and the maximum deviation is 9.3 %. When the wind speed is between 3 and 7 m/s, the energy conversion efficiency ranges from 24.4 % to 56.8 %. At a moderate wind speed of 7 m/s, the power generation can reach 6835.2 J/day, and 2460.68 kJ/year. To prevent battery discharge when there is no energy input and overcharging due to continuous charging, this paper uses an analog-to-digital converter (ADC) and a logic gate circuit to implement charging and discharging protection control for the battery, ensuring protection during charging and preventing battery discharge.