﻿ 基于空间矢量算法的三电平逆变器的研究

# 基于空间矢量算法的三电平逆变器的研究Research on Three-Level Inverter Based on Space Vector Algorithm

Abstract: This paper designs a structure of high power magnetron drive power, inverter module using a three-level inverter as a magnetron anode drive circuit. A mathematical model of the magnetron anode drive circuit was established. After mathematical analysis, the output voltage of the magnetron anode drive circuit under different switching states is derived. A simulation model was established in MATLAB, which uses SPWM and SVPWM to drive the three-level inverter. Through the comparison of simulation data, the superiority of space vector algorithm is verified from three aspects. At the same time, the waveform of the output voltage and current is obtained, which provides a theoretical basis for the subsequent application of this structure to the microwave generating device.

1. 引言

2. 磁控管驱动电源的拓扑结构

Figure 1. Anode circuit flow chart using a three-level inverter

Figure 2. Anode circuit diagram using a three-level inverter

3. 三电平逆变器的数学模型和矢量控制

3.1. 三电平逆变器的数学模型

${U}_{io}=\frac{{S}_{i}}{2}{U}_{dc}$ (1)

 (2)

Figure 3. Three-level inverter simplified model

${U}_{AN}+{U}_{BN}+{U}_{CN}=0$ (3)

$\left[\begin{array}{c}{U}_{AN}\\ {U}_{BN}\\ {U}_{CN}\end{array}\right]=\frac{1}{3}\left[\begin{array}{ccc}1& 0& -1\\ -1& 1& 0\\ 0& -1& 1\end{array}\right]\left[\begin{array}{c}{U}_{AB}\\ {U}_{BC}\\ {U}_{CA}\end{array}\right]$ (4)

${S}_{a},\text{\hspace{0.17em}}{S}_{b},\text{\hspace{0.17em}}{S}_{c}$ 表示输出线电压，则(5)式可以表示为：

$\left[\begin{array}{c}{U}_{AN}\\ {U}_{BN}\\ {U}_{CN}\end{array}\right]=\frac{{U}_{dc}}{6}\left[\begin{array}{ccc}2& -1& -1\\ -1& 2& -1\\ -1& -1& 2\end{array}\right]\left[\begin{array}{c}{S}_{a}\\ {S}_{b}\\ {S}_{c}\end{array}\right]$ (5)

$\begin{array}{c}\stackrel{\to }{U}={U}_{\alpha }+j{U}_{\beta }\\ ={U}_{A}+j\left(\frac{1}{\sqrt{3}}{U}_{B}-\frac{1}{\sqrt{3}}{U}_{C}\right)\\ =\left(\frac{2}{3}{U}_{A}-\frac{1}{3}{U}_{B}-\frac{1}{3}{U}_{C}\right)+j\left(\frac{1}{\sqrt{3}}{U}_{B}-\frac{1}{\sqrt{3}}{U}_{C}\right)\\ =\frac{2}{3}\left[{U}_{A}+\left(-\frac{1}{2}+j\frac{\sqrt{3}}{2}\right){U}_{B}+\left(-\frac{1}{2}-j\frac{\sqrt{3}}{2}\right){U}_{C}\right]\\ =\frac{2}{3}\left({U}_{A}+{e}^{j\frac{2}{3}\pi }{U}_{B}+{e}^{-j\frac{2}{3}\pi }{U}_{C}\right)\end{array}$ (6)

 (7)

${S}_{a},\text{\hspace{0.17em}}{S}_{b},\text{\hspace{0.17em}}{S}_{c}$ 的27种开关状态带入(7)式中，在αβ坐标系下画出矢量分布，如图4所示。

Figure 4. Space vector distribution

3.2. 空间矢量调制的优势

1) 直流电压利用率高

Figure 5. Output line voltage waveform

2) 总谐波畸变率小

Figure 6. Total Harmonics Distortion

3) 可以平衡中点电压

3.3. 空间矢量算法在三电平逆变器中的实现

Figure 7. Three-level inverter simulation model

Figure 8. Vector control module

Figure 9. Output voltage and current waveform

4. 结语

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[8] 袁庆庆, 伍小杰, 吴强. 低开关频率下的不对称空间矢量脉宽调制[J]. 电力电子技术, 2013, 47(5): 4-6.

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