Methodology for concurrent design of micro-power generators

The optimal performance of a micro-power piezoelectric generator for power harvesting from ambient vibrations strongly depends on the appropriate coupling among its components such as the piezoelectric element, the electrical circuit interface and the load. This coupling is governed by the different types of physical interaction phenomena occurring between such subsystems. A piezoelectric micro-power generator typically consists of a layer of active material deposited on a substrate that convert the mechanical energy from ambient vibrations into electrical energy, an interfacing circuit that usually rectifies this electrical energy and the electrical load where the harvested energy can be stored for later use or spent directly in an application. So far the research efforts in the literature have focused on the performance optimization of each of these subsystems independently, in many cases in an analytical form. Unfortunately, this approach implies a simplification of the models, ruling out most of the complex effects embedded in the dynamic behavior of the system, which does not guarantee optimal performance for the whole device once all its parts are put together. Performance is reduced in the whole device due to different effects such as dynamic loading and impedance mismatch, among others. In order to study the interaction between the subsystems of a micro-power generator, this research proposes a methodology that, by implementing the model for all components on a common a platform, allows for simultaneous analysis and design. A case study is presented and the results demonstrate the potential of the technique for cross-layer optimization of micro-power generators in connection with their associated electronics circuitry.