For the problems of output active power fluctuations and low voltage ride through in direct-driven wind power system grid-connected operation, superconducting magnetic energy storage system is added in parallel at DC-side of the converter. A novel dual closed-loop additional pulse judgment control strategy of superconducting magnet energy storage chopper is proposed, which aims to stabilize DC-side power by ensuring current level of superconducting magnet coil and making superconducting magnet energy storage charge-discharge quick and accurate. At the same time, in order to realize effective control of fluctuations caused by negative sequence components, network-side converter control strategy is improved by the introduction of resonant controller under the asymmetrical grid voltage sag condition. Simulation results show that direct-driven wind power system with the above scheme can transmit smoother real power to grid and low voltage ride through capability can be promoted.