SPWM逆变器死区效应的研究

Analysis and simulation of the dead-time effect in the PWM converter

在ＳＰＷＭ逆变器中，为防止同一桥臂上的上下两个器件发生直通现象，必须注入若干微秒的死区时间。死区会导致逆变器的波形畸变，即死区效应，如输出基波电压降低、谐波成分增大等，这种效应随着调制频率的增大而增加，其结果是影响了高速开关器件的有效利用，降低了ＳＰＷＭ调速系统的动、静态性能，增大了低次谐波的抑制难度。文章对不同使用条件下死区时间引起的输出电压基波、低次谐波的变化规律进行了系统分析，建立了定量计算的数学模型，给出了仿真曲线，并以实验结果作了验证。所得结论对于ＳＰＷＭ逆变器的设计具有一定的参考作用。

In SPWM converter, a few microseconds dead-time must be inserted in the switching singals to prevent a short circuit. This will cause the dead-time effect of the output voltage, such as the decrease of fundamental wave, increase of the harmonic amplitudes. The dead-time effects will be more serious as the modulating frequence raises up. The static and dynamic performance of the SPWM system will go down. This will make the high speed switch devices be used not effectively, and increase the difficulty of depressing the low-order harmonics. In this paper, the variation of the output base voltage and low-order harmonics in different conditions are analyzed, the models of calculation are setup, the simulated curves are given. Experiment results show the validity of the analysis. The results will be usefull to the design of SPWM inverter.