微水电是新能源的重要组成部分，但其供电质量较差，微水利用率低。为提高微水电电能质量和微水资源利用率，在传统微水发电系统的研究基础上，采用双馈发电机和双脉宽调制(pulse width modulation，PWM)变换器，分析基于交流励磁发电机和双PWM拓扑结构的可并网微水电励磁控制策略，可分为网侧和转子侧控制策略。网侧变换器采用了定子电压定向和前馈补偿控制，实现了网侧变换器直流环节电压、电流双闭环控制，有效控制了交流侧输入的有功功率；转子侧变换器采用了基于瞬时功率的开环控制，使其输出电流与电压保持同频同相，实现微水电有功和无功功率的解耦及单位功率因数并网控制。仿真实验结果表明，在亚同步转速范围内控制策略具有可行性和有效性。

Though the power supply quality of micro hydropower is poor and the utilization of micro water is low, micro hydropower is also an important part of the new energy resources. In order to improve the power quality of micro hydropower and the utilization of the micro water, on the basis of the research of traditional micro hydropower generation system, this paper adopts the doubly-fed generator and the dual pulse width modulation (PWM) converter, and analyzes the excitation control strategy for grid-connected micro hydropower based on the AC excitation generator and double PWM topology, which can be divided into grid-side control strategy and rotor-side control strategy. When it comes to the grid-side converter, it employs the stator voltage oriented and feed-forward compensation control, achieving double closed loop control of DC link voltage and current of the grid-side converter, as well as effectively regulating the AC-side input active power of the grid-side converter in the end. On the other hand, as to the rotor-side converter, it adopts open-loop control based on the instantaneous power, making the output current and voltage of the rotor-side converter keep the same frequency and phase, and realizing the active and reactive power decoupling control and the grid-connected control of the unit power factor of the micro hydropower as well. The results of simulation experiment show the feasibility and effectiveness of the control strategy in the range of sub-synchronous speed.