Optimal design for choppers in maglev trains were focused on with active auxiliary commutation circuit (AACC) techniques.Based on the operation principle and mathematical resonance analysis, it was shown that the resonance procedure of the proposed circuit was independent of the operational condition, which simplified circuits design constraints; Imprecise switching-on time on main device soft switches effect was also analyzed, which led to a general detection method to control the switching-on time, moreover, implementation issues were discussed to provide insight for engineers.