Stability Analysis of Voltage Controlled Buck Converter Feed From A Periodic Input

The ripples of dc input voltage belong to cascaded systems are usually close to the sinusoidal voltage, and its stability is quite different from that of dc constant voltage converters. Under the premise of no loss of generality, this article takes the output voltage of front-end converter in a cascaded system as sine wave, discusses the principle of closed-loop switching converters driven by sinusoidal input voltage, and calculates the average value of fixed-point state variables by using a discrete-time mathematical model. In addition, Filippov method is adopted to predict bifurcation by calculating the eigenvalues of Monodromy matrix belonging to the whole system, and the mechanism of nonlinear phenomena is also addressed. The results show that bifurcation points change obviously under different input conditions. Moreover, the influence of sinusoidal ripples amplitude and phase shift on bifurcation behavior is discussed, the compensation technique is used to prevent bifurcation and obtain the extended stability region of the circuit parameters. The experimental results prove the validity of the analysis.