中文摘要：

三电平逆变器相较于传统的两电平逆变器具有输出电压谐波畸变率小、开关管电压应力小等优点,因而在大功率场合受到了越来越多的关注.本文针对一种复合式单相三电平逆变器,对其中的分岔和混沌现象进行了深入的研究,建立了电流闭环比例控制下的一阶离散模型,得到了不同时间段内的频闪映射模型.以比例系数k,负载电阻R,负载电感L及输入电压E为变化参数,研究了三电平逆变器的分岔现象：通过分岔图和李雅普诺夫指数谱分析了慢变尺度下比例系数、负载电感、负载电阻和输入电压对系统动态性能的影响;通过折叠图直观地观测到了快变尺度下不同比例系数、负载电感所导致的分岔过程.最后搭建了Matlab/Simulink仿真模型,得到了电流闭环比例控制时电流i的时域波形,仿真结果与理论分析相一致.研究表明,正确选择单相三电平逆变器的电路参数对于其稳定运行具有重要意义.

英文摘要：

Compared with traditional two-level inverter, three-level inverter has the advantages of low output voltage harmonic distortion, and small switch voltage stress, so it attracts more and more attention in high power applications. In this paper, the bifurcation and chaos in a single-phase three-level inverter are studied. The one-dimensional discrete iterated mapping model under proportional control is established, and the stroboscopic maps in different periods of time are obtained. The bifurcation phenomena in the single- phase three-level inverter are studied when the proportional coefficient k, load resistance R, load inductance L and input voltage E are used as changing parameters. Effects of all these parameters on the system dynamical performances are analyzed on a slow scale using the bifurcation diagram and Lyapunov index spectrum. The bifurcation processes on a fast scale caused by changing values of proportional coefficient and load resistance are visually observed using folded diagram. Finally, the time-domain waveforms with different proportional coefficients are obtained by Matlab/Simulink, which corresponds with the theoretical analysis. The results show that the correct circuit parameters of single-phase three-level inverter are very important for its stable operation.