导　　师： 邹云屏

学科专业： 080801

授予学位： 博士

作　　者： ;

机构地区： 华中科技大学

摘　　要： 三相PWM整流器是目前整流器领域研究的热点，由于其具有双向能量流动性，以及交流电流波形和功率因数任意可控性，应用场合越来越广泛。直接功率控制对变换器的瞬时功率直接进行闭环控制，本文主要内容即对三相电压型PWM整流器的直接功率控制技术进行全面深入的研究。 根据瞬时功率理论，推导和建立了三相PWM变换器的功率数学模型。通过分析PWM整流器的有功功率和无功功率的功率流向，阐述了其工作原理。基于数学模型，分别研究每个开关矢量在矢量空间中对瞬时功率的不同影响，提出了一种非固定18扇区矢量空间划分方法，基于这种划分方法提出了新的开关矢量表。这种开关矢量表不仅可以克服传统开关表对无功功率控制上的缺陷，获得更好的稳态和动态控制效果，而且可以对其他开关表的不足进行一定的解释，具有很强的通用性。 根据直接功率控制的特点，提出了PWM整流器交流侧电感值、直流侧电压值和直流侧电容值的设计计算方法。通过数学推导，得出了系统参数间相互关系，有利于指导系统设计。本文引入了数字控制器的实时性因子概念，来考察直接功率控制的数字化对控制效果的影响，同时给出了整个数字控制系统延迟时间的最大容忍值，并提出衡量数字控制系统效果的真实环宽的概念。死区效应也是影响波形质量的一大原因，本文通过分别分析死区时间对变换器交流侧电压和交流电流的影响，将死区时间对PWM整流器的影响归纳为死区的电压效应和电流效应，给出了这两种效应的表达式，并给出了一种优化的死区设置方法，该方法实现简单且不会增加控制器的负担。 采用滞环比较器的直接功率控制系统的开关频率不固定，是实用化过程中需要解决的一个技术问题。将采用PI调节器的直接电流� Three-phase PWM rectifiers, which have more and more widespread applications, is in a hot research area, because their ability of two-way energy flowing, as well as arbitrary AC current wave and power factor. Direct power control is a kind of method, which directly control converters' instantaneous power with closed-loop. The main content of this paper is to conduct a comprehensive in-depth study about direct power control in PWM rectifiers. According to the instantaneous power theory, the three-phase PWM rectifier's mathematical power model is established. By analyzing the energe flow of PWM rectifier's active power and reactive power, its working principle is powered on. Based on the mathematical model to examine the different effects for instantaneous power of each switch vector in the vector space, a non-fixed 18 sectors dividing method with a novel switching vector table is proposed. They not only can overcome the defects of the traditional one in reactive power control, resulting better steady-state and dynamic effects, but also can give a certain explanation to the lack of other tables. Under the features of direct power control, main circut components design methods are proposed, including: value of the AC side inductor, DC capacitor and DC side voltage. The inter-relationship between the system parameters is researched to guid system design. A concept of real-time gene is introduced to digital direct power control system, to scale the influence of the digitalized system. At the same time, the greatest tolerance value of the entire digital control system delay is given. Another concept: real hysteresis-band is also introduced to measure effect of digital control system. Dead-time is one of the most impacts on the waves' qualities. Through analysis of impact on the AC side voltage of the converter and grid current respectively, dead-time effect can be summed up as voltage-effect and current-effect to the PWM rectifier. The expressions of these two effects are dedused. The switch frequency of

关 键 词： 整流器 脉冲宽度调制 直接功率控制 瞬时功率理论 滞环控制 数字化控制 虚拟磁链定向

领　　域： [电气工程]