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.