To address the prominent current-harmonic problem in electric-vehicle permanent magnet synchronous motor (PMSM) drive systems caused by the nonlinear coupling between the motor and inverter, and to overcome the limitations of existing methods—namely, selective suppression of only specific harmonic frequencies, potential fundamental-component deviation, difficult parameter tuning, and high implementation complexity—a hybrid topological fifth-order filter (HTFOF) based on a second-order generalized integrator (SOGI) is proposed. By augmenting the SOGI with a low-pass filter and a second-order filter to form a composite fifth-order structure, the proposed HTFOF strengthens the suppression of high-order harmonics while maintaining good dynamic performance. It can synchronously filter a pair of orthogonal signals, enabling simultaneous harmonic elimination in the α- and β-axis currents. Simulation and experimental results demonstrate that the proposed HTFOF effectively suppresses the DC component and the 5th, 7th, 11th, and 13th harmonics, while ensuring that the fundamental component experiences no amplitude attenuation and no phase shift. In addition, the filter features a simple structure and straightforward parameter tuning, avoids parameter coupling issues inherent in traditional multi-loop control schemes, and significantly reduces control-loop complexity. Moreover, it exhibits strong robustness over a wide speed range, with filtering performance that is minimally affected by operating conditions.