Salar Chamanian

Towards a vibration energy harvesting WSN demonstration testbed

This paper presents initial results toward the implementation of a wireless sensor network (WSN) demonstration testbed powered up by vibration energy, as part of the E-CROPS project. The testbed uses MicaZ Motes, supplied by AA batteries. The power drawn by Motes in different modes of operation are measured. Design details of an electromagnetic harvester, and experimental results of charging AA batteries with this harvester at 10 Hz vibration generated in the laboratory, are presented.

A self-powered integrated interface circuit for low power piezoelectric energy harvesters

This paper presents a CMOS integrated interface circuit for piezoelectric energy harvesters (PEH). A fully self-powered circuit, based on Synchronous Electric Charge extraction (SECE) technique, is implemented for non-resonant piezoelectric harvesters generating low power, in 10s to 100s μW range. The circuit is realized in standard 180 nm UMC CMOS technology. A switch control circuit is designed and optimized to extract maximum power independently from excitation changes of the PEH. The total power loss of the switch control circuit is reduced to 3.6 μW. The simulations with an output voltage range of 1.1 to 4 V show maximum power conversion efficiency of 83% (at 4 V) for a higher power PEH module, and maximum power conversion efficiency of 75% (at 2.6 V) for a lower power PEH module.

Triple Hybrid Energy Harvesting Interface Electronics

This study presents a novel triple hybrid system that combines simultaneously generated power from thermoelectric (TE), vibration-based electromagnetic (EM) and piezoelectric (PZT) harvesters for a relatively high power supply capability. In the proposed solution each harvesting source utilizes a distinct power management circuit that generates a DC voltage suitable for combining the three parallel supplies. The circuits are designed and implemented in 180 nm standard CMOS technology, and are terminated with a schottky diode to avoid reverse current flow. The harvested AC signal from the EM harvester is rectified with a self-powered AC-DC doubler, which utilizes active diode structures to minimize the forward- bias voltage drop. The PZT interface electronics utilizes a negative voltage converter as the first stage, followed by synchronous power extraction and DC-to-DC conversion through internal switches, and an external inductor. The ultra-low voltage DC power harvested by the TE generator is stepped up through a charge-pump driven by an LC oscillator with fully- integrated center-tapped differential inductors. Test results indicate that hybrid energy harvesting circuit provides more than 1 V output for load resistances higher than 100 kΩ (10 μW) where the stand-alone harvesting circuits are not able to reach 1 V output. This is the first hybrid harvester circuit that simultaneously extracts energy from three independent sources, and delivers a single DC output.

An adaptive piezoelectric energy harvesting interface circuit with a novel peak detector

This paper presents a fully self-powered interface circuit with a novel peak detector for piezoelectric energy harvesters (PEH). This circuit can be utilized to scavenge energy from low power environmental vibrations in 10s of μW range. Synchronous switching technique is used to extract maximum available power where switching instants are detected independently from excitation changes of the PEH. The proposed peak detector senses voltages higher than power supply for a wide frequency range of input vibration. The simulations with an output voltage range of 1 to 3.3 V show power conversion efficiency between 79% and 88% for an input power of 13.2 μW.