Internal model and feedforward composite control scheme design of the brushless doubly-fed generator back to back converter

The back to back pulse width modulation converter has many advantages such as bidirectional power flow and adjustable power factor as AC-supply for doubly-fed wind power generator. When the generator-side converter working condition changes abruptly, the DC-link voltage will fluctuate significantly. To stabilize the dc bus voltage and decrease the capacitor capacity, a composite control scheme of both internal model decoupling control strategy and the load power feedforward control strategy is presented, in which the feedforward compensation can offset load disturbance. The design scheme is analyzed and compared in the small signal model and the simulation results in MATLAB/Simulink environment. It is verified that the composite control scheme can quickly realize DC voltage stability and greatly improve the control effect of the DC bus voltage. Theory and simulation prove the feasibility and effectiveness of the control scheme. © State Grid Electric Power Research Institute Press.