【作者】 李艳；

【导师】 阮新波；

【作者基本信息】 南京航空航天大学 ， 电力电子与电力传动， 2009， 博士

【摘要】 新能源的开发利用是解决能源危机及环境污染问题的有效措施,但新能源受到气候和天气条件限制,大多具有电力供应不稳定、不连续等缺点。将多种新能源联合起来组成新能源联合供电系统,利用各种新能源之间或新能源与其它能源之间的互补性,可得到较为稳定的电力输出。在该系统中,采用一个多输入直流变换器(Multiple-Input Converter,MIC)代替原有的多个单输入直流变换器,可以简化系统结构、降低系统成本。本文研究MIC的电路拓扑及控制策略。目前已有文献提出了一些MIC电路拓扑,也有文献提出了MIC电路拓扑的生成方法,但还不太完善。本文首先将MIC电路拓扑分为脉冲源单元和输出滤波器两部分,提出了一系列脉冲源单元,给出了MIC的生成规则,包括脉冲源之间的组合和嵌入规则以及脉冲源和输出滤波器的级联规则。在此基础上,推导出一系列MIC电路拓扑,包括同时供电和分时供电,非隔离型和隔离型。这些电路拓扑涵盖了以前文献所提出的各种MIC,并得到了一些新的MIC电路拓扑。本文还对部分隔离型MIC电路拓扑结构进行了合理简化,并给出了简化原则。本文以双输入Buck直流变换器为例,介绍非隔离型MIC的工作原理和输入输出特性。该变换器具有电路结构简单、两种输入源既可同时向负载供电,也可独立向负载供电等优点。针对该变换器,本文分析了两只开关管开关频率相同时,其驱动信号相位与电感电流脉动的关系,提出了一种交错双沿调制方法,采用该方法可以大大减小电感电流脉动。由于MIC与单输入变换器有所不同,本文还讨论了双输入Buck变换器的主电路参数设计,并完成了一台400 W的原理样机,验证了该变换器的工作原理,并且从电感电流纹波和变换器效率两个方面验证了交错双沿调制方法的有效性。本文以双输入全桥直流变换器为例,介绍隔离型MIC在双路源同时供电和单路源独立供电两种模式下的工作原理。该变换器采用双移相控制策略,可以实现开关管的零电压开关。本文讨论双输入全桥变换器的主电路参数设计,并研制了一台800 W的原理样机,对该电路的工作原理以及软开关实现情况进行了实验验证。为了实现可再生能源的优先利用,需要对新能源联合供电系统进行能量管理。本文提出了一种新的控制策略,使新能源联合供电系统可以工作在多种模式,从而使负载功率尽可能多地由可再生能源提供,剩余功率由其它供电电源提供;而且在单路源独立工作模式下,该系统工作于电压电流双闭环,提高了动态响应速度。在多种工作模式下,控制系统中的电压闭环和电流闭环的工作情况是不同的。本文结合双输入Buck变换器,建立了该变换器和控制系统的小信号数学模型,提出了一种闭环调节器的设计方法,即在单路源供电的模式下,设计两个闭环调节器,然后在双路源供电的模式下,验证所设计的调节器是否有效。该方法保证了各种模式下系统均能稳定工作,并且可在各种工作模式之间能够平滑切换。本文最后基于一台400W的双输入Buck变换器的原理样机进行了实验验证,结果表明该设计方法是有效的。更多还原

【Abstract】 Renewable energy has been receiving more and more attentions for solving the energy crisis and environmental pollution. Most renewable energy are intermittent and random not possible at all times because they are strongly dependent on the climates and weather. But they are mutually complementary in the sense that they can be utilized simultaneously to maintain continuous delivery of power to the load, which can be named as hybrid renewable power system. In such systems, the use of a multiple-input dc/dc converter (MIC) leads to simpler circuit and lower cost, compared to the conventional use of several single-input converters. This paper focuses on the topologies and control strategies of MICs.Recently, several types of MIC topologies have been proposed and the approaches for synthesizing MIC topologies have been reported in some papers, but they are imperfect in a sense. In this paper, by decomposing converters into basic cells, namely, the pulsating source cell and the output filter, a set of the pulsating source cells and the basic rules for connecting cells are proposed. Based on which, a systematic method for synthesizing of MICs is proposed, and all of the existing MIC topologies and numerous new ones can be generated systematically, which include non-isolated and isolated ones. Furthermore, the isolated MIC topologies are simplified. Since the configuration of a double-input Buck dc/dc converter is very simple and all of the power sources can deliver power to the load either individually or simultaneously through this converter, it is chosen as an example in this paper to illustrate the operating principle and characteristics of the non-isolated MICs. In addition, this paper discusses the relationship between the inductor current ripple and the phase difference among the drive signals of the two switches, and an interleaved dual-edge modulation (IDEM) is proposed in order to minimize the inductor current ripple. As a result, the filter inductor can be reduced significantly, leading to a fast dynamic response and a high power density. The IDEM can be applied to other double-input converters. A 400 W prototype is fabricated to verify the theoretical analysis and the effectiveness of the IDEM.A specific dual-input full-bridge dc/dc converter is chosen as an example to illustrate the operating principle and characteristics of the isolated MICs. The dual phase-shift control strategy are proposed so that the converter can operate in two operation modes, in which the power sources can deliver power o the load either simultaneously or individually, and the switches realize zero-voltage-switching (ZVS). The parameters design procedure is also shown and an 800 W prototype is built to verify the theoretical analysis and the effectiveness of the control strategy.In order to utilize the renewable energy as much as possible, power management is necessary for the hybrid renewable power system. In this paper, an effective power management strategy is proposed, by which this system can operate in several operation modes and the demanded power of the load is provided by renewable power source as much as possible and the rest is provided by the other power source. Moreover, when only one source powers the load, the system operates with a dual-loop, where the voltage loop is the outer loop and the current loop is the inner one, leading to a fast dynamic response. Due to the existence of the several operation modes, the current and voltage regulators will operate in the different situations. In this paper, the small-signal model of the hybrid power system with a dual-input Buck dc/dc converter is derived, and an effective design approach of the closed-loop system is proposed. The current and voltage regulators are designed firstly when one source powers the load individually; and then they are checked when two sources power the load simultaneously. A 400 W prototype was built and experimentally evaluated. The experimental results show that the system with the designed regulators can operate stably at various operating modes and can transit smoothly among the multiple operation modes.更多还原