南京工程学院
车辆工程系
本科毕业设计（论文）
题目：多电平逆变器设计
专业：自动化（车辆电子电气）班级： K车电气071
学号：
学生姓名：
指导教师：副教授
起迄日期：2011.2.21～2011.6.10 设计地点：车辆工程实验中心
摘要
近年来在运动控制领域多电平中压变频器的开发研究得到了广泛关注，多电平逆变器使得电压型逆变器的大容量化、高性能化成为可能，具有降低开关管耐压值，减小开关管电压应力，改善输出波形质量，提高系统的电压和功率等级等优点，研究和开发多电平逆变器，无论在技术上还是在实际应用上都有十分重要的意义。
所以多电平技术由于越来越广泛的应用于高压大功率领域。
目前，在高压大功率领域中，二极管箝位型三电平变换器是研究最多，应用最广的一种多电平拓扑结构。
[1]
本文主要对二极管箝位型三电平逆变器进行研究，以此拟作为今后进一步研究的基础。
论文首先详细地介绍了三电平逆变器的工作原理，并在此基础上详细分析了其特性，综合比较了多电平逆变电路三种典型拓扑结构的优缺点。
然后，研究了三电平逆变器空间电压矢量调制技术的基本原理，分析了空间电压矢量调制算法相对于其它方法的优点。
详细分析了空间电压矢量调制算法，并给出PWM波的计算公式和开关动作次序。
对开关矢量的作用顺序作了有利于中点电压控制的优化，使仿真和实现都比较容易。
最后，分析了三电平逆变器直流侧电容电压不平衡问题的产生。
介绍了一种实现中点电压平衡的理论。
提出了一种基于MATLAB的建模方法，并通过MATLAB/SIMULINK仿真结果验证了该方法的正确性。
采用MATLAB/SIMULINK仿真软件对所推导的三电平逆变器SVPWM调制算法进行了仿真分析，证明了该调制算法的正确性。
并与两电平SVPWM调制算法的仿真进行了比较，进一步证明了三电平SVPWM调制算法在谐波抑制和减小器件开关损耗方面的优越性。
关键词：多电平逆变器；空间矢量脉宽调制；中点平衡；MATLAB/SIMULINK仿真
ABSTRACT
Recently, with the fast development of power Electronics, micro electronic technique, computer technology and modern control theory, The multilevel inverters have got large attention in power electronic industry and the applications of the high powered A.C motors’ motion control.
Multilevel technology has become all effective and practical solution for high-voltage high-power application field. As described in many literatures, using multilevel technology, the voltage stress on switches will be reduced, the shape of output waveform will be improved and the rate of voltage and power can be increased too. Diode-clamped three-level inverter is the most widely used and investigated topology at present.
As the basis of further researches, the paper mainly focuses on the control system of diode-clamped three-level inverter.
First, the principle of two-1evel inverter is detailed to introduced，and based on it, the paper deeply analyzes fundamental principle，performance and development of three-level inverter，and compares the advantages and disadvantages of three kinds of typical multilevel circuit．
Then, the principle of the voltage vector modulating technique is studied，the advantage of the voltage vector modulating calculation is analyzed comparing with other means. The next in order，the three-1evel space voltage vector control method is analyzed in detail．The formulas about PWM pulse and the order of switches action are also presented．The order of switches action is also optimized in this text，which call be propitious to the control of midpoints voltage．At the same time，the simulating and implement can also be easier．
At last, t he production of capacitance voltage’s imbalance belongs to direct current sides of three．1evel inverter is analyzed in this text．Then, A theory which can realize the balance of midpoint’s voltage is introduced；At the same time，a modeling method found on MATLAB is hereby brought forward．and then this method’s correctness is validated by emulation results. The SVPWM modulating means of three．1evel inverters is simulated by MATLAB，and the correction of modulating means is proved．Comparing with the SVPWM modulating results of two-level inverters，The superiority is further proved，which belongs to the SVPWM modulating means of
three-level inverters at the aspects of restraining harmonic and minishing switching wastage.
Keywords：Multi-level ，Inverter，SVPWM，Neutral point palance
MATLAB/SIMULINK，Simulation。