M. Orabi, T. Ninomiya, and C. Jin (Japan)
PFC stability – nonlinear phenomena – boost converter – two-stage PFC
Power factor correction (PFC) converter circuit is a non-linear system due to the contribution of the multiplier. This non-linearity reflects the difficulty of analysis and design. Designers prefer to work in the direction toward putting some assumptions that reduce the system to a linear model. Very huge output capacitance in the output of the pre-regulator PFC boost converter is assumed to result in the constant output voltage that makes the system linear. Therefore, the stability problem can be resolved and the region of stability is determined. However, an instability phenomenon has been found in this PFC stability region that was determined depending on the linear model making us more susceptible toward it. Therefore, it becomes essential to investigate the instability of two-stage PFC converter by using a non linear model. A new practical issue for the PFC converter is introduced. The practical instability regions and the borderlines are explained. The detected unstable phenomena act as the period doubling bifurcation of the line frequency. The unstable phenomena and its dynamics are explained. The effect of the line frequency is examined. Experimental results are obtained for the pre-regulated PFC and two-stage PFC converters. Simulation results verified the experimental ones with a very good matching.
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