US 11,939,961 B2
Method and system of positive and negative sequence rotor currents control for doubly-fed induction generator-based wind turbines under single dq-PI control structure
Lei Ding, Shandong (CN); Xuesong Gao, Shandong (CN); and Guofang Zhu, Shandong (CN)
Assigned to SHANDONG UNIVERSITY, Jinan (CN)
Filed by SHANDONG UNIVERSITY, Shandong (CN)
Filed on Dec. 12, 2022, as Appl. No. 18/079,431.
Application 18/079,431 is a continuation of application No. PCT/CN2021/111333, filed on Aug. 6, 2021.
Claims priority of application No. 2020107903527 (CN), filed on Aug. 7, 2020.
Prior Publication US 2023/0250803 A1, Aug. 10, 2023
Int. Cl. F03D 7/04 (2006.01); F03D 7/02 (2006.01); H02P 9/00 (2006.01); H02P 101/15 (2016.01)
CPC F03D 7/045 (2013.01) [F03D 7/0272 (2013.01); F03D 7/0284 (2013.01); H02P 9/007 (2013.01); F05D 2270/54 (2013.01); F05D 2270/71 (2013.01); H02P 2101/15 (2015.01)] 9 Claims
OG exemplary drawing
 
1. A method for positive and negative sequence rotor currents control of a doubly-fed wind turbine generator under a single dq control structure, comprising:
extracting positive and negative sequence components of a stator terminal voltage of a doubly-fed wind turbine generator;
tracking and phase locking the positive sequence components of the stator terminal voltage;
adjusting a reference value custom characterr_ref−*− of a negative sequence rotor current according to the negative sequence stator terminal voltage to obtain a reference adjustment value of the negative sequence rotor current, a conversion formula for adjusting is:

OG Complex Work Unit Math
wherein, custom characterr_com−*− is the reference adjustment value, custom characterr_ref−*− is the negative sequence rotor current reference value, the Kref and KUneg depend on parameters of the doubly-fed wind turbine generator, and vary with ωPLL and ωr, and need to be updated in real time according to the ωPLL and ωr, wherein ωPLL is a rotational speed of a forward-rotating dq coordinate system, and ωr is the rotational speed of a rotor; Ir_ref−*−
superimposing the reference adjustment value of the negative sequence rotor current with a reference value of a positive sequence rotor current in the forward-rotating dq coordinate system as an input to a PI current feedback control function in the forward-rotating dq coordinate system; and
controlling turn-on and turn-off of a switching device by using a switching signal of a rotor-side converter obtained from the PI current feedback control function, then controlling a output voltage of the rotor-side converter.