M. S. Bhuyan

Parametric analysis of boost converter for energy harvesting using piezoelectric for micro devices

Lower amount of power delivered from piezoelectric based ambient vibration energy harvester devices is a barrier to adopt the technology for different applications. Energy harvesting circuitry can enhance power output to provide a regulated DC supply to the end application. In this paper, various circuit simulations are carried out to investigate output power enhancement. A parametric analysis of a boost circuit simulation using Cadence OrCAD Capture PSpice software with input less than 1 V is carried out to find the optimum parameters including, the switching frequency rise and fall times, duty cycle, inductance and load capacitance value. Simulation results show that passive component based boost converter can significantly increase the voltage output of an ambient vibration based energy harvester. The output voltage increases linearly with the increase of single supply voltage input range 0.1 V to 0.5 V, to the output voltage range of 7 to 35 V. The optimum parameter found for 10 kΩ load is 100 μH inductor and 1μF load capacitor. A comparison of output performance of the boost circuit with existing literature is presented. The ease of the boost converter circuit will facilitate the development of an efficient piezoelectric energy harvesters for low power applications like automotive, healthcare portable devices, and wireless sensor networks.

Bluff body fluid interactions modelling for micro energy harvesting application

In this paper, we have presented a MEMS-based piezoelectric fluid-flow based micro energy harvester. The design and modelling of the energy harvester structure was based on a piezoelectric cantilever affixed to a bluff-body. In a cross fluid flow, pressure in the flow channel, in the wake of the bluff body, fluctuates with the same frequency as the pressure variation caused by the Karman Vortex Street. This fluctuation of pressure in the flow channel causes the piezoelectric cantilever, trailing the bluff-body, to vibrate in a direction normal to the fluid flow direction. COMSOL finite element analysis software are used for the evaluation of various mechanical analysis of the micro energy harvester structure like, physical the Stress and Strain state in the cantilever structures, Eigen frequency Analysis, Transient analysis to demonstrate the feasibility of the design. Detailed steps of modelling and simulation results of the uniform cantilever were explained. The results confirm the probability of the fluid flow based MEMS energy harvester.

Modeling and Finite Element Analysis of a micro energy harvester

Remote energy efficiency for wireless micro sensor devices in multimedia, signal processing and communication technologies is of paramount interest not only for ensuring continuous network operation despite primary battery limitations, but also for reducing carbon footprint in communication systems. Increasing demands of energy supply for micro devices, in particular, with the advance of complex multimedia tasks, and shorter communication distances as in sensors or machine-to-machine communications, energy cost of signal processing becomes comparable to transmit energy. Battery limitations can be partly alleviated by energy harvesting technology that can collect various forms of energy such as solar, wind, kinetic from ambient environment and convert into electrical energy. In this work, device modeling and Finite Element Analysis (FEA) of a Micro-Electro-Mechanical Systems (MEMS) Energy Harvester (EH) is presented. The MEMS-EH converts ambient fluid-flow into electrical energy by piezoelectric means. A layered flexible cantilever that vibrates due to the fluid-flow Kármán Vortex Street generated in the wake of a D-shaped bluff-body is modeled in COMSOL Multiphysics. Different application modes were carried out to investigate various response of the MEMS-EH and feasibility of the design. Simulation of the MEMS-EH in Laminar fluid Flow Regime showed von Mises effective stress 10.97 GPa and the maximum displacement of the cantilever tip 60 μm. The MEMS-EH has no rotating part and without any tip mass. Design guideline of the MEMS-EH model is presented in detail followed by simulation results. From the analysis, the prospects of this fluid-flow driven MEMS-EH device to function as an efficient kinetic energy conversion into electricity for micro sensor is reported.