Simulation Technique and Mathematical Basis for Faster AC Analysis of Power Factor Correction Boost Converters

Power factor correction (PFC) boost converters are widely used for single-phase industrial ac-dc applications, where simulation is typically used for design and verification. However, running simulations with an ac source at the line frequency (50-60 Hz) can be time-consuming due to the long line period compared to the converter switching period. For PFC converters, the control loop, input impedance, and output impedance are critical to analyze the converter performance. We show that the ac analysis of the control loop and output impedance yields the same frequency response when using an ac and dc voltage source with the same rms value for a single-phase constant-frequency PFC boost converter operating in continuous conduction mode with a high power factor. The mathematical basis for this finding is derived based on a line-averaged rectified converter model. In contrast, for the ac analysis of the input impedance, an ac source must be used for the simulation. A mathematical derivation of this result is presented based on a line-averaged ac-side converter model. From these findings, the use of a dc source for ac analysis of the control loop and output impedance reduced the simulation time to less than 6.8% of that with an ac source.