PERFORMANCE EVALUATION OF VOLTAGE RECTIFIERS FOR ENERGY HARVESTING APPLICATIONS

Voltage multipliers are used to convert the low AC voltage output of energy harvesters into relatively high DC voltage for portable devices and wireless sensor nodes (WSNs) applications. DC voltage conversion is required to operate an electronic device or recharge battery. In order, to convert the low AC voltage output of the energy harvester into relatively high DC voltage, a voltage multiplier circuit need to be integrated with the energy harvester. In this study, a Prototype-1 (two-stages) and Prototype-2 (three-stage) Dickson voltage multipliers and Prototype-3 (seven-stage) Cockcroft-Walton voltage multiplier circuits are developed. The device is capable of converting a low voltage of 50 mV into 350 mV. The research focuses on the development and characterization of Prototype-1, Prototype-2 and Prototype-3 circuits. Results indicate that the determination of load resistance is important for better output power. The maximum power of 11.97 μW was obtained by prototype-3 elucidating better power compared to prototype-1 and prototype-2 and the power was obtained at an optimum load of 560 kΩ. Furthermore, a rectenna tested at different distances from the source, revealed that a prototype-2 produced a maximum power of 3.01 × 10 -6 μW, at an optimum load of 560 kΩ.