【作者】 朱选才；

【导师】 徐德鸿；

【作者基本信息】 浙江大学 ， 电力电子与电力传动， 2009， 博士

【摘要】 燃料电池发电是21世纪重要的分布式新能源发电方式之一。燃料电池发电系统由于具有功率密度大、效率高、噪音低、环保、适应性强,不受地域、气候限制等特点,在一些需要高功率密度和高效率电源的领域,如交通、通信、计算机网络、航空航天、国防等,有着良好的应用发展前景。本文主要针对以下三项研究内容展开：1.燃料电池发电系统结构和高效功率变换的研究；2.负载动态特性匹配的能量管理技术；3孤岛检测和保护技术。在本文的第一章中,介绍了燃料电池的基本工作原理、类型、发展和一些典型的应用；对典型的燃料电池发电系统结构作了回顾,介绍了一些典型的电路拓扑结构；对用于保护燃料电池工作寿命,提高燃料利用率的能量管理技术研究现状进行了小结；介绍了现有的一些孤岛检测方法。高效的功率变换技术是提高燃料电池容量利用率,降低整个燃料电池发电系统成本的关键。本文的第二章从燃料电池的静态和动态输出特性测试出发,根据系统要求,设计了应用于燃料电池并网发电系统的两个隔离型软开关前级DC／DC变换器,分别为采用逆阻型IGBT的电流型全桥ZCS-DC／DC变换器和采用MOSFET的电压型全桥ZVS-DC／DC变换器。以两个变换器的设计作为具体实例,从功率开关应力、输入电流纹波、变换效率和动态特性等几个方面对两个变换器设计做了对比,通过仿真或实验对分析进行了验证。然后综合比较结果确定了更适合应用于本燃料电池发电系统的结构。能量管理技术的主要功能是在系统负载变化时,提供负载功率中的高频分量,保障燃料电池的工作安全。本文的第三章从超级电容的储能利用率和对负载功率冲击抑制两方面出发,对比了燃料电池发电系统能量管理单元中不同储能元件的接入方式。通过对燃料电池动态特性的测试得到了能量管理的设计指标,分析和设计了燃料电池发电系统中的能量管理单元,包括控制环路的建模、控制器和滤波器的设计、超级电容的选择设计和能量管理算法的设计。通过仿真和实验结果对前面的分析和设计进行了验证。非检测区(Non-Detection Zone NDZ)是衡量和比较孤岛检测方法有效性的重要指标,因并网控制模式的不同,同样的孤岛检测方法所对应的非检测区存在差异。本文第四章基于分布式发电装置中常用的恒流并网控制模式,分析了两种最常用孤岛检测保护方法,高／低电压检测(OVP／UVP)和高／低频率检测(OFP／UFP)的NDZ特性,通过电路求解的方式获得NDZ边界描述方程,最后通过仿真结果进行了验证。本章还对基于频率检测的有源孤岛检测方法AFD方法进行了分析,针对AFD方法的NDZ难以在有功、无功偏差平面表示的问题,通过时域求解的方式对此类方法进行分析,获得其NDZ边界在有功、无功偏差坐标平面描述方程,并通仿真结果对分析进行了验证。本文的第五章介绍了燃料电池发电系统样机的设计,包括模块化的系统结构设计、控制架构设计、通讯设计以及变换器的控制设计,给出了燃料电池发电系统样机在独立运行和并网运行以及两种模式切换时的实验结果。更多还原

【Abstract】 In fuel cell power generating system, the DC power generated by the fuel cell is converted to AC power by power conversion technology, and then the energy is feed to the grid and local load. The fuel cell power generating system becomes one of the essential forms of the distributed power generation in 21st century. Because of the fuel cell power generation system with merits such as high power density, high efficiency, low noise, environmental protection, adaptive characteristics, the application with fuel cell has good prospects for development in the area which required in a number of high power density and high-efficiency power such as transportation, communications, computer networks, aerospace, defense, etc.The study of this dissertation is carried out in following three aspects:1. System structure and highly efficient power conversion research.2. Energy management techniques for dynamic characterize match with load transient.3. Islanding detection and protection technologies.In the first chapter, the introduction of the fuel cell’s basic working principle, types, development, and some typical applications are given. A statement reviewing typical fuel cell power generation system and topology structure are made. A summary of the technology research about energy management for guaranteeing the fuel cell operation life or improving fuel efficiency are carried out.High efficiency power conversion is the key technology to improve the utilization ratio of fuel cell capacity and reducing the cost of the entire fuel cell system. In chapter 2 of this dissertation, the static and dynamic output characteristics test of the fuel cell is given first. Two typical isolated soft switching DC/DC converters, the current-fed phase shift full bridge ZCS converter with reverse-blocking IGBT and voltage-fed phase shift full bridge ZCS converter with MOSFET, are introduced as the selection of the front-ended DC/DC converter. Following the requirement, the designs of the converters are introduced. The comparisons between the two designs are carried out from the switching stress, input current ripple, loss distribution & conversion efficiency and dynamic characterize. The simulation and experiment results are given to verify the analysis. Then, the comparison results are synthesized for the selection of the front-ended DC/DC converter.The main functions of the energy management are providing the high frequency portion of the load power through the auxiliary energy storage device technique, and then the operation safety of the fuel can be ensured. In chapter 3 of this dissertation, the comparisons among different connection mode of the super capacitor in energy management unit for fuel cell power generation system are introduced. The comparisons carried out in following two aspects:the utilization ratio of super capacitor and effects of the high frequency power compensation. The criteria and parameters for the energy management design are obtained from the dynamic test of the fuel cell, and then the energy management unit is analyzed and designed for the fuel cell power system. The analyses and designs contains the modeling the control loops, the design of the controller and filter, the design and selection of the super capacitor, and the design of the energy management algorithm and program function for the realization. The simulation results and experiment results are given to verify the analysis and designs.The Non-Detection Zone (NDZ) is the criteria for describing and comparing the effectiveness of islanding detection methods. For same islanding detection method, the NDZ will be different due to the different control mode. In chapter 4 of this dissertation, the Non-Detection Zone (NDZ) with passive islanding detection methods, such as OVP/UVP, OFP/UFP, for the DG system with the constant current control scheme are analyzed. The parameters of the point of common coupling such as the voltage amplitude and frequency are studied through mathematical derivation. The NDZ boundaries description represented in the power mismatch space re drawn base on the mathematical derivation. And the analysis is verified by the simulation results. The AFD method, as the mostly acceptable active islanding detection, is analyzed in this chapter. In this chapter, the AFD function is analyzed in the time domain, the frequency response with AFD method is obtained from the analysis. Then the NDZ boundaries of this method are first described in the power mismatch space re drawn based on the mathematical derivation. Simulation results are given to verify the analysis.In chapter 5 of this dissertation, the prototype fuel cell power generation system design is introduced, including the modular system structure design, architecture design of the control, communications design, and control designs of converters. The experiment results under grid-connected mode and stand-along mode of the fuel cell power system prototype are given.更多还原