PLL small signal modeling method in double-end MMC-HVDC system

• Main Authors: WANG SHUNLIANG, PENG QIAO, YU YUEXIAO, ZENG XUEYANG, LIU TIANQI, WANG FENG
• Format: Patent
• Language: Chinese; English
• Published: 14.07.2017
• Subjects: CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTINGELECTRIC POWER; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER; ELECTRICITY; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERATION; REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGYGENERATION, TRANSMISSION OR DISTRIBUTION; SYSTEMS FOR STORING ELECTRIC ENERGY; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS; TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINSTCLIMATE CHANGE

The invention discloses a PLL small signal modeling method in a double-end MMC-HVDC system. The method includes firstly obtaining the conversion relation of the electric quantity of the AC lines at both ends of the converter transformer; according to the control block diagram of a phase-locked loop, taking the voltage phase angle of the common node PCC and the output phase angle of the phase-locked loop as variables to construct a small-signal model of the phase-locked loop; according to the power current equation, obtaining the expression analysis formula of the voltage drop and the voltage phase angle difference at both ends of the AC branch connected with the converter; obtaining the linear expression of the voltage phase angle of the PCC point; and obtaining the small-signal mode complete expression of the phase-locked loop. Taking the voltage phase angle of the common point as the variable, and considering the common point voltage phase angle change caused by the equivalent impedance of the AC network co