Bifurcation analysis of five-level cascaded H-bridge inverter using proportional-resonant plus time-delayed feedback

In this paper, a traditional five-level cascaded H-bridge inverter is studied and regulated by a proportional-resonant (PR) controller. In order to extend the range of the gain of PR controller, for the purpose of achieving a fast response, a time-delayed feedback controller (TDFC) is used. Similar to the pulse width modulation (PWM) current-mode single phase H-bridge inverter that exhibits bifurcation and chaos when parameters vary, we demonstrate for the first time that the cascaded H-bridge inverter also shows similar features. From the perspective of a discontinuous map, the cascaded H-bridge inverter generally displays extraordinary complexity. Moreover, a new virtual ergodic method (VEM) is proposed to establish the mathematical model of the whole system, which helps to understand the observed bifurcation phenomena. Simulation results are given to verify the analysis.