Research on one-step-delay effect of digital control PWM inverter

This paper focused on the research on one-step-delay effect of the stability of digital control PWM Inverter. Discrete stability criterion is used to research the stability of discrete system with/without one-step-delay control respectively. The research results are shown that the one-step-delay control degrades the stability system in the high sample frequency while it may increase the stability range compared with no one-step-delay control in some low frequency band. The unique phenomenon in the low sample frequency is explained by the analysis of frequency domain and root locus. So it is deduced that the introduction of predictive control can not improve the performance of inverter in any sampling frequency. Predictive control can upgrade the performance of inverter only in the high sample frequency.