死区对开环和闭环控制SPWM逆变器输出基波电压的影响

在SPWM逆变器中,为防止同一桥臂的上下两个开关器件产生直通,必须将驱动信号注入若干微秒的死区时间,这会使逆变器输出电压产生谐波电压。通过对基于瞬时输出电压反馈控制的SPWM逆变器死区效应造成的谐波电压的分析,建立了死区效应时SPWM逆变器控制模型,研究了逆变桥臂控制信号死区时间对开环与闭环控制SPWM逆变器输出基波电压的影响。分析结果表明,对于开环控制的SPWM逆变器,随着死区时间增加,逆变器输出基波电压有效值降低,输出电压谐波分量显著增加;对于单电压闭环控制的SPWM逆变器,死区时间对逆变器输出基波电压的影响与负载有关。通过仿真研究验证了理论分析的正确性。

Influence of dead-time to the output fundamental voltage of open-loop and close-loop SPWM inverter

In SPWM inverter,microsecond dead-time must be inserted into the switching signals to prevent short circuit happened between two switching apparatus,but it will cause additional harmonic voltage to the output voltage of the inverter.By analysis of the additional harmonic voltage caused by the dead-time of SPWM inverter based on instantaneous output voltage feedback control,the close-loop control model with consideration of dead-time is established,and the effects of dead-time to the fundamental output voltage of SPWM inverter are studied.The analysis results show that the output voltage decreases with the increase of the dead-time for the open-loop SPWM inverters;while for the close-loop SPWM inverter,it relates to the load.The simulation results verify the correctness of the theoretic analysis.