基于碟式斯特林太阳能热发电机组的磁齿轮复合电机及其控制系统研究

With the raising oil prices, the debate on fossil fuels and the harder environmental legislations alternative renewable energy conversion systems are gaining more interest. Solar energy is one of the more attractive renewable energy sources that can be used as an input energy source for free piston Stirling engines. This project investigates a completely new topology for linear permanent magnet machine as an embedded generator unit in free piston Stirling engine, which is the important parts in solar dish/Stirling electric power generation systems. .The research mainly includes the following aspects: 1) To present the design and performance of a linear magnetic-geared compact machine (LMCM) with the tubular topology. Despite being naturally air-cooled, LMCM has a significantly higher power density than a liquid-cooled transverse-flux machine, whilst its power factor is similar to that of a conventional permanent magnet brushless machine. Also it has an internal overload protection. The high efficiency and low friction losses and noise are achieved by combining the actions of a speed increasing magnetic gear and a high speed permanent magnet linear brushless machine within a highly integrated magnetic circuit. 2) To describe the generator-converter arrangement, analyze the inverter switching effects and derive the switching strategy which meets the technical requirements for connecting solar dish/Stirling electric power generation system to power network. Based on the mechanism of Stirling engine and characteristics of LMCM, the relations between rectifier modulation and load impedance variation is analyzed so as to estimate the optimal translator speed of the LMCM and implement the maximum efficiency point tracking (MEPT) by an auto-disturbance-rejection controller (ADRC). A resonant control (RC) strategy is introduced into direct power control (DPC) of grid side converter. So the quasi unity power factor is obtained without the need of grid voltage phase detecting, decoupling control or rotating transformation and diminishment of the overall control bandwidth of whole system. 3) To investigate influence of translator motion and the needed power converter. One important system issue is the interaction between Stirling engine,LMCM, and converter system. The mover force affects the size of the supplying power converters, the size of the electrical machine, the amplitude of the generated power pulsations and thus the characteristics of back electromotive force. Qualitative and quantitative analysis results will be given based on the prototype experiment and theoretical derivation. .This project belongs to the applied basic frontiers of the interdisciplinary research between electric technology and thermodynamic. The research findings will lay a strong foundation to develop our own intellectual property of solar dish/Stirling electric power generation systems.

本项目针对碟式太阳能热发电机组高可靠性、高效率、低成本要求，提出一种适用于斯特林直线循环的圆筒型磁齿轮复合发电机系统，从理论分析、仿真研究和实验验证三方面，对系统运行特性与控制规律进行深入研究。 .研究内容主要包括：新型直线磁齿轮复合永磁发电机设计，其高功率密度、低噪声、高效率、无刷化特性以及自动过载保护能力非常适宜在斯特林热发电领域应用；确定适合于该发电机结构的功率变换器拓扑，通过机侧整流器的自抗扰控制策略和网侧逆变器谐振控制算法，以达到获取发电机最大效率和提高发电系统电网适应性的目的；在明确自由活塞式斯特林发动机工作机理的基础上，分析磁齿轮复合发电机及其功率变换器主要参数与斯特林热电机组运行特性的约束关系。.本项目属于电工和热工交叉学科的应用基础研究前沿，通过本项目的实施，为研制出具有我国自主知识产权的新型碟式斯特林热发电系统奠定理论与实验基础。

本项目针对碟式太阳能热发电机组高可靠性、高效率、低成本要求，提出一种适用于斯特林直线循环的圆筒型磁齿轮复合发电机系统，从理论分析、仿真研究和实验验证三方面，对系统运行特性与控制规律进行深入研究。 .研究内容主要包括：新型直线磁齿轮复合永磁发电机设计，具有双机械端口和3层气隙结构特征,其高功率密度、低噪声、高效率、无刷化特性以及自动过载保护能力非常适宜在斯特林热发电领域应用；在完成本项目提出的磁齿轮复合电机稳态性能分析的基础上，进一步改善了发电机的动态稳定性，分析了阻尼绕组对电机工作特性的影响，并建立了该新型电机的瞬态数值仿真模型，初步验证了设计方案的正确性，相关研究成果申请2项国家专利..确定适合于该发电机结构的功率变换器拓扑，通过机侧整流器的自抗扰控制策略以达到获取发电机最大效率的目的。蓄热储能环节使斯特林热电装置输出电能较为稳定，避免了因光能变化导致的电能输出不稳定，但是受工质热力特性、活塞弹性形变、气缸摩擦力等非线性因素影响，导致直线发电机动子频率产生差异，从而造成输出电压波动。本项目建立一种基于自抗扰控制器 (ADRC)的发电机单位功率因数控制策略，以达到获取发电机最大有功功率的控制目标。ADRC由线性跟踪-微分器(TD)、扩张状态观测器(ESO)和非线性状态误差反馈控制律(NLSEF) 三部分组成，通过ESO对系统状态变量和扰动信号进行同时观测，再用前馈补偿方法将扰动加以抵消。ADRC通过非线性结构配置替代传统极点配置进行控制系统设计，不依赖于被控对象具体的数学模型，通过自动补偿对象模型的失配和来自外界的扰动，实现系统的动态反馈线性化，从而提高系统的稳定性和鲁棒性。在明确自由活塞式斯特林发动机工作机理的基础上，分析磁齿轮复合发电机及其功率变换器主要参数与斯特林热电机组运行特性的约束关系。 .本项目属于电工和热工交叉学科的应用基础研究前沿，通过本项目的实施，为研制出具有我国自主知识产权的新型碟式斯特林热发电系统奠定理论与实验基础。