Research On The Energy Harvesting Technology Based On The Synchronized Charge Extraction Method

In recent years, energy harvesting technique has been rapid progress driven by the advancements of wireless technology and technological progress of low-power electronic devices. With the combination of low-power devices, the scope of application of energy harvesting has been broadened significantly.As a new type of smart material, there are broad application prospects for piezoelectric materials in the fields of energy harvesting, vibration and noise control etc. owing to their extinguish electromechanical coupling characteristics. Using piezoelectric materials to harvest energy has been become a hotspot among many research fields. Piezoelectric patch embedded in the surface of vibration structure could induce alternating voltage signals when structure is vibrated. However, the energy of AC voltage is hard to be harvested, stored or further used, so interface circuits of energy harvesting based on different minds and principles emerged naturally.The main task of this thesis is to analyze the existed Synchronized Charge Extracted (SCE) method deeply, based on which an improved scheme was proposed. Theoretical analysis supplemented related experiments were conducted to validate the availability and feasibility of novel method.First of all, working principles of classical energy harvesting and original Synchronized Charge Extracted (SCE) are introduced. Then, the original Synchronized Charge Extracted (SCE) is analyzed deeply in the non-ideal conditions, which means that the real work state of resonant circuit are considered, finding out important factors effecting harvested power. Based on the foundation just mentioned, an improved Synchronized Charge Extracted (SCE) based on novel switch control signals was proposed and analyzed theoretically, proving its availability in the aspect of increasing harvested power. All of above constituted chapter three.Secondly, experimental systems for energy harvesting were built in chapter four. Series of experiments were carried out using dSPACE simulating & controlling platform in the cantilever beam vibration system, on which piezoelectric elements were embedded. Conclusions mentioned in chapter three were testified by experiments of classical energy harvesting circuit, original SCE circuit and improved SCE circuit. For instance, the harvested power of original SCE method was independent on the load. The harvested power could be increased using improved SCE method. What's more, there exists well vibration damping effects in both of the original SCE method and the improved. Finally, considering convenience of experiment, a PCB of control system for Synchronized Charge Extracted (SCE) method were designed and fabricated by selecting low-power micro-controller MSP430 and other low-power devices in chapter five, making the controls system modular and compact, providing convenience for both original and improved Synchronized Charge Extracted (SCE) method in different experiment conditions, and reserving spaces for further updates.