【作者】 汪锐；

【导师】 阚超豪； 徐海波；

【作者基本信息】 合肥工业大学 ， 电气工程（专业学位）， 2021， 硕士

【摘要】 单级高频链功率变换器通过“直流-高频交流-低频交流“三个环节实现单级功率转换,不仅去除了多级高频链变换器中间环节的滤波稳压大电容,减小体积同时降低成本,还能通过调制策略实现开关管的软开关,提高系统效率。但是传统高频链变换器开关管换流期间存在的电压过冲现象给系统稳定性带来不利影响。针对高频链变换器的稳定性问题,提出了一种无源辅助网络器件参数的优化方法。本文主要研究内容包括以下几个方面:1、介绍了单级高频链变换器的发展历史和研究背景,探讨了此类变换器的研究意义,综述了国内外研究现状,针对不同类型的变换器,分析了高频链变换器当前发展中面临的问题。2、针对单级高频链变换器在开关管换流瞬间出现的电压尖峰和寄生振荡,分析其产生的机理,针对不同原因讨论对应的抑制方法和调制策略;在此基础上,详细分析了基于无源和有源辅助网络的高频链变换器的工作模态和换流过程;最后通过PSIM仿真验证了未添加辅助网络前变换器的电压尖峰振荡现象,以及添加辅助网络后抑制作用的有效性。3、针对变换器换流时刻的电压尖峰和振荡问题,分析了无源辅助网络拓扑,构建了含无源辅助网络的高频链变换器数学模型,从传递函数的角度分析电压尖峰产生的原因;分别对有/无源辅助网络进行损耗对比分析,研究不同拓扑的损耗来源和分布,为优化辅助网络器件参数提供依据。4、通过分析变换器工作模态,推导得到高频链变换器等效数学模型和传递函数;分析了比例谐振控制器的频率特性,获得该控制器对电网系统稳定性影响的规律;比较分析了延迟环节对数字控制器设计的影响;依据数学模型,设计了并网条件下高频链变换器双环数字控制器;最后通过PSIM和Simulink仿真,验证了并网逆变器各个环节参数设计的有效性。5、搭建了基于DSP+CPLD数字控制器的200W单级高频链DC/AC变换器试验平台。试验表明,基于无源辅助网络,能有效抑制电压过冲和寄生振荡;基于有源辅助网络,能够消除电压过冲和寄生振荡,并实现部分区间软开关运行;基于所提数学模型和控制器设计结果,实现了并网条件下对电压、电流的有效控制,验证了所提方案的有效性。更多还原

【Abstract】 The single-stage high-frequency link power converter realizes the single-stage power conversion through the three stages of "DC-high frequency AC-low frequency AC",which not only removes the filter capacitor in the middle stage of the multi-stage high-frequency link converter,reduces the volume and the cost,but also realizes the soft switching of the switch tube through the modulation strategy,and improves the system efficiency.However,the voltage overshoot of traditional high-frequency link converter during switching has a negative impact on the system stability.Aiming at the stability problem of high frequency link converter,an optimization method of passive auxiliary network device parameters is proposed.The main contents of this paper include the following aspects1.Introduced the development history and research background of single stage high frequency link converter,the significance of research of this kind of converter is discussed,the research status at home and abroad were summarized,analyzed the problems in the current development of high-frequency-link converter for different types of converter.2.Aiming at the voltage spike and parasitic oscillation of single-stage high-frequency link converter at the moment of switching,the mechanism of them is analyzed,and the corresponding suppression methods and modulation strategies are discussed for different conditions;On this basis,the operation mode and commutation process of the highfrequency link converter based on passive and active auxiliary network are analyzed in detail;Finally,PSIM simulation is used to verify the voltage surge phenomenon of the converter before adding auxiliary network and the effectiveness of the suppression after adding auxiliary network.3.Aiming at the problem of voltage spike and oscillation at converter commutation time,the topology with passive auxiliary network composed of resistance and capacitance devices is analyzed and the mathematical model is established.The causes of voltage spike are analyzed from the perspective of transfer function.The power loss sources and distribution for different topologies are studied by comparing and analyzing the power loss of active and passive auxiliary networks respectively,which provides the guidance for optimizing the parameters of auxiliary network devices.4.By analyzing the working mode of the converter,the equivalent mathematical model and transfer function of the high frequency link converter are derived;The frequency characteristics of the proportional resonant controller are analyzed,and the influence of the controller on the stability of power grid system is obtained;The influence of delay on the design of digital controller is analyzed;According to the mathematical model,the double loop digital controller of high frequency link converter is designed;Finally,through PSIM and Simulink simulation,the effectiveness of parameter design of grid-connected inverter is verified.5.A 200 W single-stage high frequency link DC / AC converter test platform based on DSP + CPLD digital controller is built.Experiments show that the passive auxiliary network can effectively suppress voltage overshoot and parasitic oscillation;Based on the active auxiliary network,the voltage overshoot and parasitic oscillation can be eliminated,and some section soft switching operation can be realized;Based on the proposed mathematical model and controller design results,the effective control for voltage and current under grid connected condition is realized,and the effectiveness of the proposed scheme is verified.更多还原