H桥型多电平逆变器PWM调制策略及控制系统研究

发布时间：2018-06-03 22:37

本文选题：3H桥型五电平逆变器 + 调制策略　；参考：《中国矿业大学》2014年硕士论文

【摘要】：多电平逆变器(multi-level inverters)具有开关频率低、谐波含量低、输出性能好等优势而广泛运用在大功率交流调速场合。本文以3H桥型五电平逆变器及电励磁同步电机(electrical synchronous motor, ESM)为研究对象，对多电平逆变器的拓扑结构、调制策略、共模电压、功率开关器件及单元模块之间的功率平衡、死区效应、3H桥型五电平逆变器控制系统等方面展开研究。首先，分析3H桥型拓扑结构的工作模式，重点分析适用于该种拓扑结构的PWM调制策略：载波调制策略(SPWM)和空间矢量调制策略(SVPWM)。结合H桥拓扑结构，针对传统载波层叠策略(CDPWM)的各开关切换次数不一致、桥臂间输出功率不平衡等问题，本文对载波带频率变化调制策略(CVFPWM)展开研究，，仿真结果验证了该方法的可行性。但是，当其向级联多电平扩展时，存在编程实现难、开关损耗大等问题。因此，本文着重介绍载波移相调制策略(PSCPWM)，对其输出波形进行仿真验证和谐波分析，该方法可以有效解决开关损耗大、桥臂间及单元模块间的输出功率平衡等问题。由于上述调制策略的直流侧电压利用率不高，因此，可在调制波中注入零序分量，该调制策略可以提高15%的直流侧电压利用率，仿真结果验证了该方法的有效性。由于传统SVPWM存在大量的三角函数和复杂的公式计算，介绍了一种基于线电压坐标系的通用SVPWM算法，该方法实现简单、易于向高电平扩展。在此基础上分析共模电压的抑制问题，给出七段式SVPWM算法，并对其进行仿真和实验验证。在五电平调制策略的基础上，分析SPWM与SVPWM之间存在的本质关系。分析五电平逆变器在输出低压、低频时的死区效应，给出一种基于脉冲和差值电压协同补偿的补偿策略。仿真和实验验证了该方法的有效性。其次，对同步电机磁链定向控制原理进行分析，分析了三种磁链定向控制下的数学模型。介绍了电流、电压综合磁链观测器，基于Matlab/Simulink仿真环境，搭建气隙磁链定向控制下的3H桥型五电平同步电机矢量控制仿真平台，仿真结果验证了3H桥型五电平变流器带电机负载的可行性。最后，搭建了3H桥型五电平变流器平台，给出了主电路器件选型的具体步骤及控制系统软件实现流程图。并对五电平控制系统调试和实验验证，完成阻感负载和电机负载的实验。
[Abstract]:Multi-level inverters are widely used in high power AC speed regulation field due to their advantages of low switching frequency, low harmonic content and good output performance. In this paper, the 3H bridge five-level inverter and electrically excited synchronous motor (synchronous motor, ESM) are studied. The topology, modulation strategy, common-mode voltage, power balance of power switch devices and unit modules of the multilevel inverter are studied. The control system of 3 H bridge-type five-level inverter with dead-zone effect is studied. Firstly, the working mode of the 3H bridge topology is analyzed, and the PWM modulation strategies suitable for the 3H bridge topology are analyzed, which are the carrier modulation strategy and the space vector modulation strategy. Considering the H bridge topology, aiming at the problems of different switching times and unbalanced output power between the traditional carrier stacking strategy CDPWMs, this paper studies the carrier band frequency varying modulation strategy (CVFPWM). The simulation results verify the feasibility of the method. However, when it extends to cascaded multilevel, there are many problems such as difficult programming and high switching loss. Therefore, this paper mainly introduces the carrier phase shift modulation strategy (PSCPWMN), and simulates the output waveform and harmonic analysis. This method can effectively solve the problems of high switching loss, output power balance between the bridge arms and unit modules, and so on. Because the DC side voltage utilization ratio of the above modulation strategy is not high, zero sequence component can be injected into the modulation wave, and the modulation strategy can increase the DC side voltage utilization ratio by 15%. The simulation results show that the proposed method is effective. Because traditional SVPWM has a lot of trigonometric functions and complex formulas, a general SVPWM algorithm based on line voltage coordinate system is introduced. The method is simple and easy to extend to high level. On this basis, the common mode voltage suppression problem is analyzed, and a seven-segment SVPWM algorithm is presented, and its simulation and experimental verification are carried out. Based on the five level modulation strategy, the essential relationship between SPWM and SVPWM is analyzed. This paper analyzes the dead-time effect of five-level inverter at low voltage and low frequency, and presents a compensation strategy based on the synergistic compensation of pulse and differential voltage. The effectiveness of the method is verified by simulation and experiments. Secondly, the principle of flux oriented control of synchronous motor is analyzed, and the mathematical models of three kinds of flux oriented control are analyzed. The current and voltage integrated flux observer is introduced. Based on the Matlab/Simulink simulation environment, the vector control simulation platform of 3H bridge five-level synchronous motor is built under the directional control of air-gap flux. The simulation results verify the feasibility of the 3 H bridge five-level converter with motor load. Finally, the 3H bridge type five-level converter platform is built, and the specific steps of the main circuit device selection and the flow chart of the control system software are given. The experiments of resistive load and motor load are carried out by debugging and verifying the five-level control system.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM464

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