抑制Z-源逆变器母线电压跌落的空间矢量脉宽调制方法

摘要

在深入分析Z-源三相逆变电路工作过程中存在的二极管断流以及由此导致的直流母线电压跌落问题的基础上,导出了直流母线电压跌落的表达式,并提出一种新的空间矢量脉宽调制(SVPWM)方法.该方法根据Z-源网络中所独有的直通工作状态,在不改变硬件电路的前提下,通过合理地插入直通零矢量来避免电路的非正常工作状态,保持直流母线电压的稳定,提高逆变器的输出电压质量.在满载和轻载两种工况下,对比分析了本文SVPWM方法和传统SVPMW方法对Z-源网络的直流母线电压的影响.最后,通过仿真和实验验证了本文SVPWM方法的正确性和有效性.%Current discontinuity flowing through the diode in Z-source network will lead to DC link voltage drop.The expression of the DC bus voltage drop is derived,and then a new space vector PWM (SVPWM) control method is proposed.Based on the shoot-through state in the Z-source network,the new method avoids the abnormal working state of the circuit by inserting the shoot-through states into the control period.The method can maintain the stability of the DC bus voltage without changing the hardware circuit,and can also improve the quality of output waveforms.Under full load and light load conditions,the effects of the new SVPWM method and the traditional SVPWM method on DC bus voltages in the Z-source network inverter are analyzed.Simulations and experiments have verified the effectiveness and correctness of the new method.