基于MRAS的多相永磁直驱型风力发电系统无速度传感器控制策略研究

Research on sensorless control strategy of direct drive multi-phase PMSG wind power generation system based on MRAS

对采用多相永磁同步发电机的大功率直驱型变速恒频风力发电系统进行了研究。系统采用六相永磁同步发电机和多重化的AC-DC-AC变换器,以减少每个电机绕组中的电流和每个电力电子变换器中的电流。研究了一种基于模型参考自适应(Model Reference Adaptive System,MRAS)的六相永磁同步发电机无速度传感器控制策略。该策略将永磁同步发电机本身作为参考模型,将发电机的电流模型作为可调模型,设计了自适应律同时辨识永磁同步发电机的转速和转子位置。还研究了基于变步长爬山法的最大功率跟踪(Maximum Power Point Tracking,MPPT)控制策略,该策略具有动态功率跟踪速度快和稳态时速度平稳的优点。实验结果表明,上述控制策略在负载突变和转速突变时均能准确地检测到发电机的转速和转子位置;在风速变化时能准确地跟踪最大功率。

A high power direct drive variable-speed constant-frequency wind energy conversion system based on multi-phase permanent magnet synchronous generator （PMSG） is researched. In order to reduce the current of each winding and each power electronics converter, six-phase PMSG and multiple AC-DC-AC converters are used. A sensorless control strategy of six-phase PMSG based on model reference adaptive system （MRAS） is researched. In this strategy, the PMSG is regarded as reference model while the current model of PMSG is considered as adjustable model. The adaptive laws are designed so that generator speed and rotor position are estimated at the same time. Maximum power point tracking （MPPT） control strategy based on step-changing climbing method is also researched. This method has a fast dynamic response and a good steady state. Experimental results prove that the proposed method is capable of precisely estimating the generator speed and rotor position under the condition of load change and speed change. When the wind speed is changing, the proposed method can also track the maximum power point.