Bifurcation analysis of cascaded H-bridge converter controlled by proportional resonant

摘要

This paper is concerned with the nonlinear dynamics of Cascaded H-Bridge Converter under PR (Proportional Resonant) control. First, a stroboscopic mapping model of PWM (Pulse Width Modulation) converter is established and the corresponding dynamics, including bifurcations and chaos is investigated analytically. Taking the switching frequency, controller parameters as the bifurcation parameter, some different dynamic behaviors are identified over a wide range of some specified parameter. Moreover, the bifurcation condition is further verified based on the root locus diagram and Lyapunov exponential spectrum. Second, aiming at deriving the stability regions of PWM converter, the variable substitution approach is utilized to transform the non-autonomous converter model into an autonomous one. Then, the PR (Proportional Resonant) controller is applied to control the grid-side current, which can suppress the chaos and bifurcation in the current loop by increasing the proportional gain. Finally, the experiment results are presented to illustrate the validity of the control scheme.