MULTI-LOOP SWITCHING CONTROL SYSTEM OF DOUBLY FED FAN BASED ON LOGIC SWITCH CONTROL

摘要

A multi-loop switching control system of a doubly fed fan based on logic switch control. Output variables of the doubly fed fan are selected as the rotor speed (ω _r) of a generator, stator side reactive power output (Q _s), reactive power output (Q _g) of a converter of grid side and the direct-current capacitor terminal voltage (V _dc) of a back-to-back converter. The four output variables are used to form four output feedback control channels, each of which switches between a switch controller and a conventional vector controller, and further form a four-loop switching controller. According to the switching strategy, when the electric power system of the doubly fed fan experiences a large external disturbance, the state variables and output variables of the doubly fed fan deviate from original balance points, and then the four control loops of the fan switch from the conventional vector controller to the switch controller; and under the effect of the switch controller, the state variables and output variables of the fan will return to the vicinity of the original balance points, and then the four control loops of the fan switch from the switch controller to the conventional vector controller.