【作者】 刘昊；

【导师】 肖湘宁；

【作者基本信息】 华北电力大学（北京） ， 电力电子与电力传动， 2005， 博士

【摘要】 脉宽调制技术(PWM)是电压源型逆变器(VSI)的共用及核心技术,总体上讲,它的理论基础可以分为基于时域的冲量等面积原理和基于矢量空间的矢量等效原理。正弦脉宽调制(SPWM)是基于前者的代表性 PWM 方式,其实现方法简单,但它割裂了各桥臂间的固有联系,孤立地分析单个桥臂的输出状态,造成逆变器输出性能低下;基于后者的代表性 PWM 方式是空间矢量 PWM(SVPWM),它虽然将所有桥臂放在同一个空间统一看待,由此获得良好的输出性能,但其计算复杂,在逆变器电平数较多时难以实现实时控制。SVPWM 的计算复杂性掩盖了它的本质,故而人们难以建立冲量等面积原理与矢量等效原理之间的内在联系。因此在 PWM 实现方式上,缺少统一的指导思想。为此,本文开展了以下研究工作。 总结典型基于时域冲量等面积原理的 PWM 方式,明确提出相电压 PWM 和线电压PWM 的思想。在此基础上,得到一种优化线电压 PWM 方式。它不仅能够提高逆变器直流电压的利用率,还可以有效地降低开关频率。 针对于两电平 SVPWM 方式,本文首次指出传统求解方法的不彻底性。并且利用三角函数知识,将其进行化简,从而得到一种简化算法。该算法避免了常规算法在求解过程中所涉及非线性运算,并且理论计算误差为 0。通过数学推导,笔者证明优化独立 PWM方式是一种特殊形式的 SVPWM。 针对于多电平SVPWM,本文首次指出坐标系选取不当是造成计算复杂的根本原因,并建立了一种新型的非正交坐标系——KL 坐标系。在此坐标系下,得到多电平 SVPWM的统一简化算法,使得整个求解过程仅含少量的乘加运算。该算法是多电平 SVPWM 的通解,它可以“无缝”移植到任意电平阶数逆变器领域。这一部分工作奠定了多电平SVPWM 实时控制的基础。随后,笔者将多电平 SVPWM 的统一简化算法由线性调制领域扩展到过调制领域。 在 KL 坐标系下,分析多电平 SVPWM 的物理意义。对于 PWM 技术中基于矢量空间的矢量等效与基于时域的冲量等面积两种理论,本文首次利用严格的数学推导建立了它们之间的联系,并且指出 SVPWM 是线电压 PWM 的真子集。 作为供电电源与用电设备间的非线性接口电路,电力电子装置不可避免地向电网注入谐波电流。而电力电子技术的发展,为谐波的治理提供了更为丰富的手段,其中有源电力滤波器是最具有发展前景的方式之一。本文基于并联混合型 APF,开展大容量谐波与无功补偿技术的研究,力图为其实用化奠定基础。 对于并联混合型 APF,本文分析了它的基本原理,阐述了其逆变器直流电压低的工作特性。对于高压系统应用,论证了基于二极管箝位式三电平逆变器的并联混合型 APF技术优点。在此基础上,本文提出了并联混合型 APF 完整的控制策略:以无差拍控制实现对指令电流的快速、准确跟踪;以 PI 控制防止交流滤波电容的电压发生直流偏移;华北电力大学博士学位论文 2采取多种措施将逆变器直流侧电容电压的稳定控制在较小幅值。上述控制策略是 APF优质、安全运行的重要保障。针对于所提出的基于二极管箝位式三电平逆变器的混合型 APF,本文对其直流电压的稳定控制环节进行了详细分析。将该问题细化分解为两个步骤:逆变器直流侧总电压的稳定控制和基于 SVPWM 的电压均衡控制。前者等同于普通基于两电平逆变器的混合型 APF 的直流电压控制,对此笔者首次指出如使直流电压稳定,不仅需要调整电网注入的有功电流,而且必须调整所注入的无功电流;对于后者,笔者提出选择合适的冗余矢量并调整其相应持续时间的方法,并且给出了对应的控制策略表。利用无源补偿装置(滤波器或电容器)的功率优势和 APF 的控制性能优势,本文开展了谐波与无功的混合补偿研究,提出二者并联运行时 APF 所应采取的控制策略。最后,本文分析了并联混合型 APF 主要器件的参数设置,进而研制控制系统硬件平台,编写实时控制软件,构建一台 380V/50kVA 实验样机,进行实验研究。在此基础上研制一台 380V/100A 试运行装置,对某电力用户发生的谐波问题进行了有效治理。关键词:SVPWM,非正交坐标系,有源电力滤波器更多还原

【Abstract】 The PWM technology is a global technique applied to the control of voltage source inverters(VSI), and its basic theory can be classified into the pulse area equal principle based on time and equivalent vectors principle based on space. SPWM is a typical PWM mode based on the former theory and can be easily realized, whereas results in lower output capability of inverters because of dissevering intrinsic relations among bridges as well as independently analyzing the output status of each bridge. Comparatively, SVPWM is another typical PWM mode based on the latter one. Although it uniformly deposits total bridges in the same space to gain favorable output capability, it is difficult to be carried out that complicated computation and real-time control when levels of inverters increase.Complicated computation of SVPWM conceals its essence, thus internal relations between pulse area equal principle and equivalent vectors principle are difficult to be established . As a result, a uniform directive idea on realization of PWM mode does not exist. Therefore, the following researches are carried out in the paper. At first, typical PWM modes based on pulse area equal principle are summarized, PWM modes based on phase voltage and line voltage are definitely proposed, and then an optimized PWM mode based on line voltage is concluded. Not only can this mode improve dc voltage utilization ratio of inverter side, but also efficiently reduced switch frequency. As for two-level SVPWM mode, that conventional solutions are not exhaustive is firstly pointed out in the papers. After trigonometric function used in simplifying solutions, a simple algorithm is deduced. The algorithm avoids non-linearity operations relevant to the conventional algorithm during the solutions, and in theory error of computation is zero. By mathematical deduction, the author proves that the optimal common mode PWM mode is an especial form of SVPWM. As for multi-level SVPWM mode, that an unsuitable coordinate to be chosen is the essential reason that results in complicated computation is firstly pointed out in the papers, and in addition a novel nonorthogonal coordinate-- KL coordinate is established. Uniform and simplified algorithm of multi-level SVPWM mode is found out on the coordinate, which enables only a small quantity of multiplication and addition operations to be performed during the whole solutions. This algorithm is a general solution of multi-level SVPWM mode, and can be constantly applied into any level inverter fields. This part of productions are the basis of real-time control realization of multi-level SVPWM mode. the author successively extends the simplified algorithm from linear modulation fields to over-modulation fields. In KL coordinate, physics meaning of multi-level SVPWM mode is analyzed. The pulse area equal principle based on time and the equivalent vectors principle based on space to be considered, the relations between them are established by accurate mathematical deduction and a conclusion that SVPWM is a subclass of line voltage PWM is presented. As non-linear pontes circuits between the supply and the facilities, power electronic devices inevitably inject harmonics into power network. On contrary, the development of electric technology provides abundant measures that can be applied into suppressing harmonics. Among these measures, active power filter is one of the most valuable researches. The research on harmonics and reactive power compensation technology are carried out in the papers in order to provide theoretic guidance for promoting APF into practice. As for shunt hybrid APF, that operation characteristics of lower dc voltage in its inverter side are explained in details in the papers, and current tracking control course based on deadbeat control theory is implemented . In order to prevent dc offset appeared on capacitor voltage of series passive power filters, the author presents dc component modulation of output currents based on PI control. For application into high voltage network, technology advantage of shunt更多还原