[Objective] To reduce the harmonic content and operating losses of high-power AC/DC converter, and realize the bidirectional energy flow, this paper proposes a rectification scheme consisting of a phase-shifting transformer (3→3N) combined with multi-pulse uncontrolled rectification. [Methods] The proposed scheme employed phase-shifting technology to expand three-phase into 3N phase, resulting in a denser phase distribution on the AC side, which effectively increased the rectification pulse frequency and reduced low-order harmonics. Meanwhile, multi-path current splitting reduced the current amplitude of each branch and achieved current sharing. The uncontrolled rectifier eliminated the switching losses caused by switching devices, with only conduction losses presented, thereby further reducing the overall system losses. The proposed scheme was compared and analyzed with two other schemes: three-phase transformer+six-pulse uncontrolled rectification and three-phase transformer + insulated gate bipolar transistor (IGBT) fully controlled rectification. The total harmonic distortion (THD) was evaluated using the root mean square calculation method based on fast Fourier transform, and the conversion efficiency was calculated as the ratio of output power to input power under steady-state conditions. [Results] The simulation results showed that under identical filter parameters and load conditions, the THD of the proposed multi-pulse uncontrolled rectification scheme was the lowest, at 7.57%, which was significantly superior to 12.87% for the IGBT rectification scheme and 17.96% for the three-phase uncontrolled rectification scheme. At full load, the efficiencies of the three schemes were 91.2%, 88.2%, and 87.8%, respectively. In the upgraded phase-shifting multi-pulse uncontrolled rectification low harmonic bidirectional extended topology, the battery current could smoothly cross zero and achieved commutation. [Conclusion] The proposed multi-pulse topology achieves low harmonic distortion and low-loss operation with minimal control complexity. The hybrid scheme combined with the fully controlled structure further expands the bidirectional energy flow capability.