周荔丹 李杏 姚钢 梅柏杉

Abstract：The mathematical model of six phase permanent magnetic synchronous generator （PMSG） with winding shifted-phase 30° was established under rotating coordinate based on the vector space decomposition theory. For the control of the multi-phase modular multilevel converter（MP-MMC） to drive the multi-phase generator， the MMC topology was extended from three phase to six phase and used to drive six phase permanent magnet wind power generator. And the current decoupling control method was adopted for base-frequency current tracing and harmonics suppressing. The close-loop control strategy was taken for the MMC internal sub-module capacitor voltage balance and the cycle current restraining. Finally， the simulation model was built under the conditions of steady state and power disturbance. The simulation results show that the system meets concerning standard and its robust performance is good. And they verify that six phase PMSG can generate electricity efficiently by MP-MMC driving.

Keywords：six phase permanent magnet synchronous generator; modular multilevel converter; vector space decouple; vector control; close-loop control

0 引 言

随着陆上风电场规模趋于饱和，海上风电由于其资源丰富、对环境影响小、利用率高等优点，已成为新能源发电的主要方式之一，发展远距离大规模化的风电场，实现大功率发电机组高压直流并网成为现阶段研究热点[1-3]。为了满足大规模海上风力发电的需求，风力发电机组的单机容量和整流变换器功率等级显著提升，电机由传统的三相电机逐步向多相电机方向发展，变流器由普通的两电平、三电平向更高电平方向发展[4]。大容量、高功率密度风力发电机的高效发电以及大功率变流器高效变换等关键问题的深入研究对超大规模海上风电场的发展具有重要的意义。

与三相发电机相比，多相发电机具有转动脉矩小、功率密度高、输出功率大、容错性能良好等优点[5-6]，已成为未来海上风力发电机的主要选择之一。对多相电机的研究，较为广泛的是双Y移30°六相永磁同步电机，此结构与对称六相永磁同步电机相比电流中不含5次和7次谐波。多相电机的建模主要依据两类方法：第一类是基于d-q解耦方法;第二类是基于矢量空间解耦方法[7]。文献[8-9]将六相永磁同步电机的六相绕组分别看成两套三相绕组，把六相电机分解成两个三相电机进行分别控制，建立了双d-q数学模型，但该模型忽略了两套电机之间耦合和差异，在两套绕组dq磁链间仍存在着耦合关系[10]，在此基础上，文献[11]对建立的双d-q电机模型进行了电流补偿控制，将电流控制器的输出和补偿量进行加和作为参考电压，实现了两套绕组间电流的独立控制。……