In traditional power converter control, proportional integral multi resonant odd harmonic repetitive control (PIMR-ORC) typically struggles to balance dynamic harmonic suppression with frequency adaptability. To address this, a second-order fractional odd-harmonic repetitive control (SF-ORC) is proposed. By extending the internal model and employing FIR filters to approximate fractional delays, this scheme adjusts the phase lead to track grid frequency fluctuations in real time. Furthermore, a parallel proportional branch is introduced to enhance the system's transient response. Stability analysis and parameter tuning are provided, and simulation results confirm the proposed method maintains superior dynamic characteristics and adaptability under frequency variations.