An Ultrasonic Piezoelectric Power Generator for Public and Industrial Buildings Application

This paper presents an ultrasonic micro power generator using the piezoelectric direct effect phenomena. The micro power generator consists of 2 main elements, a movement matt including PZT elements and an energy harvesting circuit. The movement matt is made up of a four PZT elements each element creating a cantilever beam. The energy harvesting circuit is made up of an LTC3588 Evaluation Board and an LDR night light. Computer simulation and modelling using finite element analysis for the proposed generation method is discussed and used in the design and development process. Finite element analysis has been used to evaluate the PZT structure by performing an algebraic solution of a set of equations, describing an ideal model structure, with a finite number of variables. The simulation and modelling enabled to select the material and best method of operation. A prototype of the proposed generator was built and tested. This demonstrated that piezoelectric material could produce up to 36V, although the overall impedance of such devices was shown to be linear depending on the force applied with an average of 36MΩ. The Energy harvesting circuit allowed an output super capacitor to be step charged taking an average time of 35-minutes to charge and 2-minutes to discharge through the selected load.

Simulation and Modelling for a Three-Dimensional Ocean Surface Wave using and Inverse Fourier Transform

Ocean surface waves have been utilized as fundamental information in various fields of oceanic research. In this paper, we suggest a simulation and modelling technique for generating an ocean surface wave using an inverse Fast Fourier Transform (iFFT), and we subsequently verify the wave’s accuracy. The conventional method, linear superposition, requires recursive calculation because of the double summation and the time variable; to circumvent this issue, the new algorithm is presented. The Joint North Sea Wave Project (JONSWAP) spectrum is utilized for the ocean surface wave simulation example, and the parameters are the significant wave height (HS) and the zero-crossing wave period (TZ). A coordinate transform for the wavenumber domain was used to apply the inverse FFT algorithm. To verify the accuracy of the simulation result, the relative error between the input condition and the analysis result was calculated. The result for TZ is below 4% relative error, and the maximum relative error for HS is 7%. To avoid the Nyquist frequency for wave-field analysis and simulation, the minimum grid size was calculated by twice applying the maximum wavenumber.