基于全阶状态观测器的双馈变频器低穿灭磁控制

为了解决双馈变频器低电压穿越期间定子磁链中暂态直流分量对电磁转矩的影响,以及触发转子过流保护动作,提出一种基于全阶状态观测器定子磁链观测的低穿灭磁控制方法,并对其进行了仿真验证。仿真结果表明,全阶状态观测器法观测的定子磁链都能与真实值高度吻合;全阶状态观测器法磁链观测对电机参数具有很好的鲁棒性;基于全阶状态观测器法磁链观测的灭磁控制方法效果显著,通过有效的灭磁控制,可显著改善双馈变频器的低穿性能。

风力发电机组双馈变频器与故障处理

双馈变频器在风电领域十分重要,是双馈式风力发电机组中必不可缺少的部件,其故障频发。特别是对于高穿技改后的变频器,由质量问题引起的故障十分突出。阐述变频器在风电领域的重要性、结构、作用、工作原理以及常见故障,根据现场处理变频器故障的经验,对常见故障处理方法进行了总结与整理。

探析磁环在双馈风电变频器共模抑制中的应用

在双馈风电变频器工作的过程中,转子轴上会产生较高的共模电压,此种电压有害,因此本文从磁环在双馈风电变频器中展开 抑制工作的原理入手,分析了磁环在双馈风电变频器共模抑制当中的应用细节,希望为相关工作提供合理参考。

Brushless Doubly-Fed Induction Machine as a Variable Frequency Transformer

VFT （variable frequency transformer） has been recently used as art alternative to HVDC （high voltage direct current） to control power flow between asynchronous networks. VFT consumes less reactive power than a back-to-back HVDC system, provides faster initial transient recovery, and has better natural damping capability. VFT is simply a DFIM （doubly-fed induction machine） where the machine torque controls the power flow from stator to rotor and vice versa. The main disadvantage of this VFT is the slip rings and brushes required for the rotor circuit, especially in bulk power transmission. The BDFM （brushless doubly-fed machine） with nested cage rotor machine is proved to be a comparable alternative to conventional DFIM in many applications with the advantage that all windings being in the stator frame with fixed output terminals. In this paper, the BDFM is used as a BVFT （brushless variable frequency transformer）. A prototype machine is designed and simulated to verify the system validity.