自偏置DEG基础理论及关键技术研究

A class of variable capacitor power generators called Dielectric Elastomer Generators(DEG),show considerable promise for harvesting renewable energy from ambient energy and the applications of ultra-small,self-contained, and low-power sensors and actuators because they can be direct coupled to large broadband motions without gearing while maintaining a high energy density, have few moving parts, and are highly flexible,light, and form fitting. At present, DEG cannot currently realize their full potential because they require rigid and bulky external circuitry. In this study, a self-filling DEG are presented. The self-filling DEG are electrically configured to form a pair of charge pumps. They convert some of the voltage boost into additional charge. When the extra charge produced is greater than the sum of the transferred to an external load and losses, the voltage in the DEG will climb through the accumulation of generated energy. Because of the DEG's ability to produce extra filling charges without connection to an external charge reservoir after initial filling, they can be called a self-filling DEG. The DEG are modelled using a coupled electromechanical methodology where an ABAQUS finite element model is used to model the DEG and date from this model is input to a DEG LT-Spice circuit simulation. Based on above, A soft push-pulling DEG design are presented, fulfilling self-filling functions Simultaneously, capable of overcoming electrical losses. The soft DEG do not require diodes or external energy storage devices because both functions are fully integrated onto the DEG membrane. They use the inherent capacitance of DEG to integrate the energy storage function of the capacitor bank , and use dielectric elastomer switches to control the distribution of charge. Different small scale prototypes of energy harvesting devices have been developed so far. Nevertheless, theoretical limits still have to be considered. The amount of energy gain depends, beside of the mechanical setup of the device, mainly on the material parameters and the utilized energy harvesting cycle. In this study, detailed loss mechanisms are take into account to derive energy gain and efficiency models. Based on these results, the different energy harvesting cycles are combined to establish an energy-optimal cycle, in order to maximize the overall energy gain and efficiency. Then,the energy-optimal cycle can be fulfilled by solving the extremum problem of the derived energy gain.In additional, a nonlinear approach enhancing the electromechanical conversion capability of DEG, is proposed to be a solution for artificially increasing the coupling factor of electroactive dielectric elastomer materials. The method consists in adding an electrical switching device connected in parallel with the electroactive elements. The switch triggers on maxima or minima of the voltage and realizes a voltage inverse through an inductor.

介电弹性体发电机（DEG)是一种具有独特性能的新型发电机,在诸如自持性微机电系统及波浪/风能等发电领域极具应用前景。 项目针对DEG研究的两个瓶颈问题-偏置机制及发电效率开展研究：①基于现有DEG材料及经典电路理论，研究自偏置原理，建立具有升压及电荷提升特性的自偏置电路模型；利用Simulia ABAQUS及LT-Spice等仿真工具，并经实验修正，建立自偏置DEG的机电耦合模型；进行一种柔性、推拉式DEG的新型结构方案设计，在实现DEG自偏置机制的同时，无需使用"硬的"传统电子器件，以解决自偏置机制的实现与电子器件电能损耗之间的矛盾这个关键问题；②建立自偏置DEG电能增益及发电效率计算模型；组合基本发电循环，建立新的发电循环优化模型；通过求解电能增益的极值问题，研究循环优化控制方法这个关键问题；并研究一种非线性电能转换方法，提高DEG机电耦合因素；③制作样机，实验验证及优化以上理论。

介电弹性体发电机（DEG）是一种新型的发电机型式，特别适用于可持续能源利用、如海洋能/风能发电领域，具有成本低、无污染、能量转换效率高等特点，具有广阔的应用前景。本项目研究在COMSOL有限元环境中建立了DEG在单轴、剪切、双轴三种变形方式下的有限元模型，对拉力、电容变化、升压能力等方面进行了仿真分析与实验研究；其中，针对DE作为大变形超弹性材料的非线性力学特性，基于Mooney-Rivlin模型等四类超弹性本构模型，对DE材料的力学本构进行了分析研究，通过复合拟合获得了合适的本构模型并确定了其本构参数，提高了有限元模型的准确性。基于经典理论，分析了电荷泵原理，研究和建立了DEG的自偏置机理，分析了自偏置DEG的能量转换过程及输出电压变化规律，设计了基于电荷泵的新型自偏置电路，实现了自偏置功能。针对DEG发电效率问题，研究了的DEG损耗机制，基于恒电压、恒电荷和恒电场三种基本发电循环方式，研究建立了新的组合循环优化模型，并结合DEG非线性机电转换方法，探索了提高电能增益的方法和技术手段。项目针对制约DEG研究的基本理论和关键技术问题，所得成果为DEG进一步的应用基础研究提供了支撑。