本文为美国德克萨斯A&M大学（作者：MESAAD WALEED ALBADER）的硕士论文，共139页。
现代电力电子系统使用不同的电压和/或频率额定值，如可调速度驱动、微型电网、不间断电源（UPS）和高压直流输电系统。为了使电力电子系统与主电源相匹配，使用了直流链路变换器。直流链路变换器的第一级是AC/DC变换器（整流器）。整流型公用电接口存在大量谐波，由于功率因数低、谐波失真大，导致电能质量差。
功率因数校正（PFC）方案是解决谐波问题的有效方法。本文对高功率密度整流器的三种方法进行了分析。在第一项研究中，模块化三相升压整流器在DCM中工作，以增加功率密度。这种整流器的主要缺点是电源和直流链路侧的高电流纹波，从而需要较大的EMI滤波器尺寸（可能大于整流器元件尺寸）和较大的直流滤波器电容尺寸。本文提出耦合式模块化三相升压型直流整流器，电源侧和直流侧的电流相互交错，因此电流纹波大幅减小，使得EMI滤波器和直流滤波电容的元件尺寸减小，从而获得高功率密度整流。此外，还提出了优化整流模块数量以达到最大功率密度的方法。同时，每个整流器的开关功能采用谐波注入技术来减少低次谐波。直流输出电压随负载功率的变化而变化，并工作于CCM和DCM之间的边界，以实现最大功率密度跟踪。
在第二项研究中，为了克服传统单开关三相功率因数校正电路中高5阶和7阶电流谐波的缺点，提出了一种谐振式三相单开关功率因数校正电路。对于开关频率下具有高电流纹波的每个单独的低阶谐波，输入电流具有低THD。为了减小输入电流的纹波，还提出了用耦合模块整流器交错输入电流的方法。分析并推导了系统方程和工作方式，设计了所需输出电压和负载功率的电路参数、开关频率和占空比。
在第三项研究中，通过采用中频电子移相器取代低频变压器来减小系统的尺寸和重量，对现有的模块化T型连接单相PFC进行了改进。与Y、Delta和T连接的单相功率因数校正模块相比，该方法具有更高的功率密度。研究了交流斩波器的3～2相转换、系统谐波、开关技术以及系统的功率通量。
Modern power electronic systems operatewith different voltage and/or frequency rating such as Adjustable speed drive,Micro Grid, Uninterruptable Power Supplies (UPS) and High Voltage DCTransmission Systems. To match power electronic systems with the mains supply,DC link converters are used. The first stage of the DC link converter is theAC/DC conversion (rectifier). The rectifier type utility interface hassubstantial harmonics result in poor power quality due to low power factor andhigh harmonic distortion. Power Factor Correction (PFC) schemes are effectivemethods to mitigate harmonics and address this issue. In this thesis, analysesof three approaches for high power density rectifiers are developed. In thefirst study, modular three phase boost rectifiers operating in DCM are coupledin order to increase the power density. Major drawback of this rectifier is thehigh currents ripple in both the source and the DC link sides which requirelarge EMI filter size -could be larger than the rectifier component size- andlarge DC filter capacitor size. This thesis proposes coupling modular threephase boost DCM rectifiers, the currents in both source and DC link sides areinterleaved and consequently the currents ripple dramatically decreased resultsin small component size of the EMI filter and the DC filter capacitor leadingto high power density rectification. Also, optimization of the number of therectifier modules to achieve maximum power density is presented. Moreover, theswitching function of each rectifier employs harmonic injection technique toreduce the low order harmonics. And, the DC output voltage is varied with theload power such that the operation is at the boundary between CCM and DCM toachieve maximum power density tracking. In the Second study, a resonant threephase single switch PFC is presented to overcome the high 5th and 7th ordercurrent harmonics drawback in the conventional single switch three phase PFCcircuits. The input current has low THD for each individual low order harmonicswith high current ripple at the switching frequency. Interleaving the inputcurrent by coupling modular rectifiers is also presented to reduce the inputcurrent ripple. System equations and modes of operation is analyzed and derivedto design the circuit parameters, switching frequency and duty ratio for thedesired output voltage and load power. In the Third study, an advancement ofexisting modular T-connected single phase PFCs by means of replacing the lowfrequency transformer with medium frequency electronic phase shifter to reducethe size and weight of the system. The approach has higher power densitycompared with the Y, delta and T-connected single phase PFC modules. The studyexamines the 3 to 2 phase conversion, system harmonics, switching technique forthe AC chopper and the power flow of the system.
1 引言与文献综述
2 高功率密度的交错式三相DCM整流器
3 高输入电能质量、高功率密度的三相谐振整流器
4 采用两个单相功率因数校正和一个电子移相器的模块化三相功率因数校正方法
5 结论
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