Fast-Scale Bifurcation Analysis in One-Cycle Controlled H-Bridge Inverter

This paper discusses the fast-scale instability in the one-cycle controlled H-bridge inverter which is widely used in practical applications. Simulations show that the fast-scale instability which occurs around the peak value of the inductive current is a type of local instability. The discrete-time model is derived to analyze the fast-scale instability. According to the Jacobian matrix derived from the discrete-time model, the theoretical analysis shows that the fast-scale instability manifests itself as a period-doubling bifurcation occurs, which reveals the intrinsic mechanism of the instability of one-cycle controlled H-bridge inverter. Furthermore, with the approximation of the matrix exponential in the discrete-time model and based on the Jacobian matrix, the stability boundary is obtained by the analytical expression which is helpful to select the proper values of parameters for avoiding the fast-scale instability. The experiments are carried out to validate the results of the simulation and theoretical analysis. It is shown that the analysis method is able to facilitate the design of the inverter.