US 12,438,372 B2
Island microgrid system, and interactive oscillation suppression method and system therefor
Yandong Chen, Guangdong (CN); Jian Guo, Guangdong (CN); Wenhua Wu, Guangdong (CN); Zhiwei Xie, Guangdong (CN); Leming Zhou, Guangdong (CN); Xiaoping Zhou, Guangdong (CN); Qianming Xu, Guangdong (CN); and Zhixing He, Guangdong (CN)
Assigned to Guangdong Zhicheng Champion Group Co, Ltd., Guangdong (CN)
Appl. No. 18/269,464
Filed by GUANGDONG ZHICHENG CHAMPION GROUP CO., LTD., Guangdong (CN)
PCT Filed Nov. 7, 2022, PCT No. PCT/CN2022/130250
§ 371(c)(1), (2) Date Jun. 23, 2023,
PCT Pub. No. WO2023/083128, PCT Pub. Date May 19, 2023.
Claims priority of application No. 202111332841.9 (CN), filed on Nov. 11, 2021.
Prior Publication US 2024/0047969 A1, Feb. 8, 2024
Int. Cl. H02J 3/24 (2006.01); G05B 6/02 (2006.01); H02J 3/38 (2006.01)
CPC H02J 3/24 (2013.01) [G05B 6/02 (2013.01); H02J 3/388 (2020.01)] 8 Claims
OG exemplary drawing
 
1. An interactive oscillation suppression method for an island microgrid system, wherein the island microgrid system comprises a plurality of power supply units; each power supply unit comprises a source-side virtual synchronous generator and a load-side virtual synchronous generator; the source-side virtual synchronous generator and the load-side virtual synchronous generator are connected in series; the load-side virtual synchronous generator is connected to a load; and the interactive oscillation suppression method comprises the following steps:
obtaining an output voltage amplitude Em of the source-side virtual synchronous generator according to a d-axis component ud of three-phase output voltage of the source-side virtual synchronous generator, instantaneous reactive power Q of the source-side virtual synchronous generator and an instruction value Qset of the instantaneous reactive power Q, wherein a calculation formula for Em is as follows:
Em=(Dq(Un−ud)+Qset−Q)/(Ks);
wherein Dq represents a given reactive power-voltage droop coefficient; Un represents a rated terminal voltage amplitude of the source-side virtual synchronous generator; K is a given excitation regulation coefficient; and s is a Laplace operator;
obtaining a phase angle θ of the source-side virtual synchronous generator according to active power P of the source-side virtual synchronous generator and an instruction value P* of the active power P, wherein a calculation formula for θ is:

OG Complex Work Unit Math
wherein Dp represents a damping coefficient; ωn represents a synchronous angular velocity of an island microgrid system; and J is a rotor inertia of the source-side virtual synchronous generator;
obtaining a voltage instruction value ud* of the d-axis and a voltage instruction value uq* of the q-axis according to the voltage amplitude Em of the source-side virtual synchronous generator, wherein the instruction values ud* and uq* are calculated as follows:

OG Complex Work Unit Math
wherein id and iq are a d-axis component and a q-axis component of three-phase current of the source-side virtual synchronous generator respectively; and Rv and Lv are a resistance value and an inductance value of given virtual impedance respectively;
solving a differences between the voltage instruction value ud* of the d-axis and a d-axis component of three-phase voltage of the source-side virtual synchronous generator, and solving a difference between the voltage instruction value uq* of the q-axis and a q-axis component of three-phase voltage of the source-side virtual synchronous generator, and respectively performing PI control on the differences to obtain current instruction values id0* and iq*;
calculating an instruction value id* of the d-axis current component of the three-phase output current of the source-side virtual synchronous generator by using the following formula: id*=id0*−id1*+id2*;
solving a difference between the d-axis current instruction value id* and a d-axis component id of the three-phase current of the source-side virtual synchronous generator, and solving a difference between the q-axis current instruction value iq* and a q-axis component iq of the three-phase current of the source-side virtual synchronous generator, and using the differences as input of a PI controller respectively to obtain a duty ratio dd of the d-axis and a duty ratio dq of the q-axis; and
obtaining duty ratios da, db and dc in a three-phase static coordinate system according to the duty ratio dd of the d-axis, the duty ratio dq of the q-axis and the phase angle ϑ of the source-side virtual synchronous generator, and controlling on-off of a switch tube of the source-side virtual synchronous generator according to the duty ratios da, db and dc according to the duty ratios da, db and dc,

OG Complex Work Unit Math