Abstract: This study focuses on the research of a single-stage single-phase active power factor correction (PFC) Cuk topology AC-DC converter, with emphasis on analyzing the performance characteristics of the closed-loop Cuk PFC converter. It is shown that buck or buck-boost converters exhibit discontinuous input current under any input line voltage and output load conditions; boost converters are limited by the stress on power electronic devices caused by high voltage. The input current characteristics of the Cuk converter are similar to those of the boost converter, but it regulates the output voltage through power factor correction and inner/outer voltage control loops. When the input voltage and output load change, it can reduce the total harmonic distortion (THD) of the input current, achieve a power factor close to 1, and optimize the output voltage stability under different input/output scenarios. This paper compares the performance of open-loop Cuk rectifiers, closed-loop Cuk rectifiers, and standard diode rectifiers, develops relevant control algorithms and conducts simulation verification, and completes the design of the closed-loop Cuk rectifier in a digital environment.