This paper presents a frequency adaptive extended ripple voltage state observer (FA-ERVSO) control strategy to enhance the robustness of totem-pole bridgeless power factor correction (TPBPFC) converters against performance degradation arising from parameter mismatch in conventional ERVSO implementations during grid frequency fluctuations. By analyzing the performance degradation mechanism of a fixed-parameter ERVSO under frequency deviation, its strong dependence on frequency matching is revealed. A second-order generalized integrator phase-locked loop (SOGI-PLL) is employed for real-time grid frequency identification, and a parameter adaptation method is designed to adjust observer and controller parameters online. Simulation results at a grid frequency of 40 Hz show that the proposed FA-ERVSO reduces input current THD from 8.25% (fixed ERVSO) to 0.60% while maintaining excellent ripple suppression and dynamic response. Furthermore, the proposed strategy effectively compensates for output voltage ripple, improves input current quality, and maintains system stability under grid frequency transients and load variations, achieving adaptive adjustment of system dynamic performance in response to grid frequency changes. These features significantly enhance the adaptability and robustness of the converter in non-ideal grid conditions.