摘 要

航空静止变流器作为新式飞机上常用的二次电源，已广泛地用于给机载设备提供稳定可靠的电能。随着飞机用电容量的增加，对航空静止变流器的容量和可靠性的要求也逐渐增加。提高其容量和可靠性的一个有效方法就是实现逆变器的并联及冗余控制。

本文首先介绍了常用于航空静止变流器的三相逆变器拓扑，对它们进行了优缺点分析和比较，由于三相四桥臂逆变器拓扑具有拓扑结构简单且能带不平衡负载，因此将其作为本文的研究对象，然后对现有的逆变器并联控制技术进行了分类和比较。

然后在abc坐标系下和αβ0坐标系下对三相四桥臂逆变器进行了建模研究，并得到了由abc坐标系向αβ0坐标系的转换公式，确定在αβ0坐标系下对三相进行独立地控制。

分析了传统的三相三桥臂逆变器的SPWM的调制策略，并推广到三相四桥臂逆变器的SPWM调制策略。在MATLAB/Simulink中搭建了三相四桥臂逆变器的仿真模型，验证理论分析结果。

接着，本文分析了两台逆变器的环流特性，明确了如何才能从根本上抑制环流的产生。对逆变器输出的有功和无功功率进行了推导研究，得出逆变器输出有功和无功与其输出电压的幅值和相位存在的量化关系。采用调节逆变器输出功率的方法实现对负载电流的均分，从而达到抑制环流的目的。推导了一种有功和无功功率的数字化检测方法，结合DSP技术实现有功功率和无功功率的在线实时计算，提高系统的响应速度。最后介绍了基于DSP的逆变器并联同步锁相技术，实现输出波形的同步。

在本文理论分析的基础之上，在两台满载功率为6kVA的三相四桥臂逆变器样机上进行了实验验证。首先得到了单台逆变器的稳态和动态特性，然后做了三相四桥臂逆变器的并联实验，实验结果验证了本文的理论分析，性能指标也达到了预期效果。

关键词：三相四桥臂； SPWM调制；环流； 并联； 同步锁相

Abstract

Aviation static inverter, which is commonly used in the new type of aircraft, has been widely used to provide stable and reliable power supply for airborne equipment. With the increase of the capacity and reliability of the aircraft, the requirement for the capacity and reliability of the static inverter is gradually increased. An effective way to improve the capacity and reliability of the inverter is to realize the parallel and redundant control of the inverter.

This paper first introduces different topologies of the three phases inverter and carries out a comparison among them, since the three phase four legs inverter’s topology is simple and it hold the unbalanced load. so the three phase four legs inverter was chosen as the research focus in the paper. Different parallel technologies have been classified and compared according to their control parameters.

The mathematical model for three phase four legs was built in abc and αβ0 coordinate system. And the conversion matrix for the transformation was derived from abc coordinate system to αβ0 coordinate system, finally the control method was realized in αβ0 coordinate system to control three phases independently.

The Sinusoidal Pulse Width Modulation stratagem was analyzed in the traditional three phases three legs inverter and was extended into three phases four legs inverter. The three phases four legs inverter simulation model was built in Matlab/Simulink, the theoretic results was verified in the simulation.

The circulation current characteristics of two inverters were analyzed, and how to restrain the generation of the circulation current is clarified. The active and reactive power of the inverter is derived, and the conclusion is obtained that the amplitude and phase of the output of the active and reactive power of the inverter has a quantitative relation with the amplitude and phase of the output voltage. By adjusting the output power of the inverter, the load current is divided equally, so as to achieve the purpose of suppressing the circulation current. A digital detection method of active and reactive power is derived, which can improve the response speed of the system by combining the DSP technology to realize the on-line real-time calculation of active power and reactive power. At last, the paper introduces the parallel synchronous phase locked technology of inverter based on DSP, and realizes the synchronization of output waveform.

On the basis of theory mentioned in this paper, experimental verification was carried out on the prototype of a three-phase four leg inverter with full load power of 6kVA. Firstly obtain the steady-state and dynamic characteristics of the single inverter, and then do the three-phase four leg inverter parallel experiment. The experimental results on the theoretical analysis provides the support of theory, performance index has reached the expected.

Key Words：Three Phase Four Legs; SPWM; Circulation Current; Parallel; Synchronization Phase-Locked Control

目录

摘 要 I

Abstract II

1 绪论 1

1.1 航空静止变流器的研究背景 1

1.2 大功率航空静止变流器拓扑 2

1.3 逆变器并联控制技术 4

1.3.1逆变器并联技术概述 4

1.3.2 逆变器并联技术按控制量分类 5

1.4 本文主要研究内容 5

2三相四桥臂逆变器建模分析 6

2.1 三相四桥臂逆变器的数学模型 6

2.1.1 三相四桥臂逆变器abc坐标系模型 6

2.1.2 三相四桥臂逆变器αβ0坐标系模型 7

2.2 逆变器调制策略 9

2.2.1 三相三桥臂逆变器的SPWM调制 10

2.2.2 三相四桥臂逆变器的SPWM调制 11

2.3 三相四桥臂逆变器仿真分析 12

2.4 本章小结 16

3三相四桥臂逆变器并联控制 18

3.1逆变器并联系统环流特性 18

3.2基于有功和无功功率控制的均流方法 20

3.3有功和无功功率的检测 20

3.4并联逆变器同步锁相技术 22

3.5本章小结 23

4 三相四桥臂逆变器并联系统的实验结果 24

4.1 6 kVA样机介绍 24

4.2 单机运行实验结果 24

4.3 并联运行实验结果 25

5 总结与展望 27

5.1 本文工作总结 27

5.2 工作展望 27

参考文献 29

致 谢 30

附录1 31

附录2 32

1 绪论

• 1. 航空静止变流器的研究背景

在飞机上的二次电源之中，航空静止变流器(Aeronautic Static Inverter, ASI) 可以将发电机或航空蓄电池的电能转换为115 V/400 Hz交流电给机载用电设备提供可靠的电能，是航空二次电源系统中不可或缺的组成部分。从飞机的层面来讲，首先航空电源系统要满足机载设备对大功率电源的需求。供电系统功率密度的提高意味着在提供相同功率的情况下其体积和重量可以降低；电源系统效率的提高意味着降低飞机上能源的损耗以及电源系统的发热；另外，飞机上的电气设备的安全稳定运行也取决于供电电源系统的高度可靠性，一旦电源系统发生故障，那么造成的损失将是巨大的^[1-3]。而且电源系统中由于存在高频开关的功率电子器件，向外辐射的电磁干扰也会对飞机上重要的通信设备造成影响。因此进一步提高航空静止变流器的功率密度(Power Density)、效率(Efficiency)、可靠性(Reliability)并降低ASI的EMI是一项重要的课题。

旋转变流机曾作为早期的航空变流器，其基本结构采用测是直流电动机-交流发电机。旋转变流机的缺点是：体积重量大，噪音大，效率低且难于维护。随着电电力电子技术的发展以及功率半导体器件的发展，20世纪70年代，随着航空静止变流器取代了笨重的旋转变流机，为飞机提供了易维护性和高可靠性的电源系统。目前在国内，大部分的航空静止变流器的电气规格为28 V输入，单相或三相交流115 V/400 Hz输出。随着飞机对电源容量要求的提高，一些新式飞机开始采用270 VDC输入，且为了减小变换器的重量，提高功率密度，一般采用两级变换方案。前级DC-DC实现升压变换的同时，也将输入与输出隔离，相当于原本的中频隔离变压器倍高频变压器所取代，前级DC-DC变换将电压升高至360 V之后供给后级逆变器，作为后级逆变器的直流输入。