An Active Voltage Doubling AC/DC Converter for Low-Voltage Energy Harvesting Applications

Abstract

This paper theoretically and experimentally investigates an ac/dc converter for low-voltage vibrational energy harvesting systems. The circuit employs an active-diode-based voltage doubler, where the output is a dc voltage that is twice the amplitude of the input ac voltage. Analytical solutions for the steady-state open-circuit voltage are derived, capturing the effects of the activediode comparator hysteresis. It is shown that the hysteresis plays an important role in the rectification characteristics, circuit stability, and overall efficiency. Experimentally, the circuit is able to rectify input voltage amplitude as low as 5 mV and operates over a frequency range of 1 to 500 Hz, which spans most common mechanical vibrations. For input voltage amplitudes 250 mV or higher, the circuit exhibits >80% efficiency for a range of load resistances, delivering 0.1-10 mW of power. Additionally, the circuit successfully rectifies the voltage from a vibrational energy harvester having a highly irregular and time-varying voltage waveform.Index Terms-AC/DC converter, active diode, energy harvesting, voltage doubler.

Review of Power Conditioning for Kinetic Energy Harvesting Systems

“…Similar to synchronous bridge rectifiers, active VM typically use comparator-controlled MOSFETs, and therefore, the principles discussed in the active rectifier section are relevant here. In cases where the input voltage level is greater than 1 V, peak power efficiencies in submilliwatt designs of active voltage doubler circuits can reach up to 94% [52] in integrated designs, or 92% [53] (not including the power consumption of the comparators) when discrete components are used. The efficiency of these designs is highly dependent on the input power level as well as the load current.…”

A Compact Human-Powered Energy Harvesting System

“…), with much fewer exploring harvesting mechanical energy from humaninduced vibrations. Additionally, most interface circuits designed for vibrational energy harvesting are powered either by an external power supply or by the circuit output (Szarka, Stark, and Burrow February 2012;Chao 2011;Peters, Ortmanns, and Manoli 2007;Le et al 2006;Peters et al 2008;Lam, Ki, and Tsui 2006;Cheng et al 2009;Anton, Erturk, and Inman 2009;Mendez-Delgado and G. Serrano 2010). When used in complete vibrational energy harvesting systems, standby power of the interface circuits may drain the energy storage element and cause a startup problem after if there is a long idle time interval between two harvesting cycles.…”

A highly efficient interface circuit for ultra-low-voltage energy harvesting

“…In this case energy harvested from ambient sources offers a promising solution to the problem. And harvesting ambient vibration energy through piezoelectric (PE) means is a popular way to harvest energy [1,2]. The structure of vibrational energy harvesting system is shown as Fig.…”