中文摘要：

本文研究了单相H桥逆变器在单极性正弦脉宽调制下的分岔和混沌行为，建立了系统在比例控制下的一阶离散映射模型，采用分岔图、折叠图和Lyapunov指数谱分析了比例系数k对系统性能的影响，通过Matlab／Simulink仿真得到了不同比例系数下的时域波形图，验证了理论分析的正确性．最后运用分岔图研究了输入电压E、负载电阻月和电感L等外部参数变化时变换器中存在的非线性行为．本文将单相H桥逆变器的混沌研究从双极性正弦脉宽调制转向单极性正弦脉宽调制，使之更具实用性，研究结果对于正确设计和调试单相H桥逆变器具有重要的指导意义和应用价值．

英文摘要：

The unipolar SPWM has been widely used in H-bridge inverter because of its superiority for lower switching loss and less electromagnetic interference as compared with bipolar SPWM. However, the nonlinear phenomena in it have not been reported. In this paper, the bifurcation and chaos in the H-bridge inverter modulated by unipotar SPWM is studied. The one-dimensional discrete iterated mapping model under proportional control is established. Effects of the proportional coefficient k on the system performance are analyzed by using bifurcation diagram, folded diagram, and Lyapunov index spectrum. The time-domain waveforms with different proportional coefficients are obtained by Matlab/Simulink, which verify the correctness of theoretical analysis. Finally, the nonlinear behavior in the inverter caused by the variation of other circuit parameters like input voltage E, load resistance R, and inductance L is investigated through bifurcation diagrams. This paper turns the chaotic research of single-phase H-bridge inverter from bipolar SPWM to unipolar SPWM, So that the proposed approach is more practical. The results have important guiding significance and application value for designing and debugging the single-phase H-bridge inverter correctly.