Coordinated Control Based Doubly-fed Induction Fan System and Its Low Voltage Ride Through Method

Abstract

The invention discloses a doubly-fed induction fan system based on coordinated control and a low-voltage ride-through method, which is characterized in that it comprises: a doubly-fed induction fan stator winding, a doubly-fed induction fan rotor, a rotor-side converter, and An inductive superconducting fault current limiter connected in series between the rotor and the rotor-side converter; wherein, the fault current limiter includes superconducting coils and power electronic switches connected in parallel. By combining the inductive superconducting fault current limiter and improving the control technology of the double-fed induction fan rotor side converter, the superconducting fault current limiter is used to directly limit the rotor overcurrent, reduce the torque oscillation, and at the same time utilize the double-fed The reactive power output of the induction motor itself improves the low-voltage ride-through capability of the double-fed induction fan; at the same time, through the precise control of the rotor-side converter current during the fault period, the key parameter setting principle of the fault current limiter is determined, effectively reducing The impedance value of the superconducting fault current limiter used is improved, and the cost is saved.

Description

technical field [0001] The invention relates to the technical field of doubly-fed fan equipment, in particular to a doubly-fed induction fan system based on coordinated control and a low-voltage ride-through method thereof. Background technique [0002] Wind power generation is a power generation method with the largest installed capacity in new energy power generation. With the increasing penetration of wind power in the power system, the performance of wind turbines under grid faults is becoming more and more important for system stability. Common wind turbines include doubly-fed induction generators and permanent magnet direct drive generators. DFIG (double-fed induction fan) has the advantages of low cost, wide speed range, independent control of active and reactive power, etc. Due to its advantages for realizing grid integration, wind turbines based on doubly-fed induction generators are more commonly used in wind power generation. [0003] However, DFIG is sensitive...

AI Technical Summary

Problems solved by technology

[0003] However, DFIG is sensitive to grid disturbances due to its direct connection to the grid at the stator end

The occurrence of severe voltage sags and the resulting stator flux response can cause significant electrical stress on the rotor-side converter and severe mechanical stress on mechanical components such as gearboxes

This low voltage operation also inhibits the full transmission of the power generated by the doubly-fed induction generator to the grid, which will lead to a large increase in the fluctuation of the DC voltage

In order for the doubly-fed induction generator to meet the low voltage ride-through requirements, several issues must be properly resolved in the event of a fault: the first is the problem of the rotor surge current that occurs in the rotor circuit due to the stator flux response, and the second One is the problem of DC overvoltage

By introducing a superconducting fault current limiter to limit the fault current of the DFIG, although better low-voltage ride-through performance can be obtained, it does not combine the operating characteristics of the DFIG itself, and the key parameters of the DFIG cannot fully meet the low Voltage ride-through requirements will also lead to higher costs

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