【目的】为降低大功率AC/DC变换器的谐波含量与运行损耗，并实现能量双向流动，本文提出了一种移相变压器(3→3N)+多脉波不控整流的整流方案。【方法】所提方案利用移相技术将三相扩展为3N相，使交流侧相位分布更加密集，从而有效提高整流脉波频率并削弱低次谐波；同时多路分流使得每一路电流幅值减小，电流得到分担。不控整流器避免了开关器件带来的开关损耗，仅存在导通损耗，进一步降低了系统整体损耗。将所提方案与三相变压器+六脉波不控整流以及三相变压器+绝缘栅双极晶体管(IGBT)全控整流两种方案进行对比分析。采用基于快速傅里叶变换的均方根计算方法评估总谐波畸变率(THD)，通过稳态下的输出与输入功率比值计算转换效率。【结果】仿真结果表明，在相同滤波参数及负荷工况下，本文所提多脉波不控整流方案的THD最低，为7.57%，显著优于IGBT整流方案的12.87%和三相不控整流方案的17.96%；在满载条件下，三种方案效率分别为91.2%、88.2%和87.8%；在升级后的移相多脉波不控整流的低谐波双向扩展拓扑中，电池电流可平滑过零并实现换向。【结论】所提多脉波拓扑在控制复杂度较低的前提下，可实现低谐波失真与低损耗运行，结合全控结构的混合方案进一步拓展了能量双向流动能力。

[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.

群众性创新科技项目(520911250002)