锁相环对锁相环型并网变换器有功/无功电流激励-内电势幅值/频率响应关系的影响机制研究  

Influence Mechanism of PLL on Active/Reactive Current Excitation and Internal Voltage Amplitude/Frequency Response Relationship of PLL-based VSC

作　　者：龚轩 袁小明[1] 胡家兵[1] GONG Xuan;YUAN Xiaoming;HU Jiabing(State Key Lab of Advanced Electromagnetic Engineering Technology(School of Electrical and Electronic Engineering,Huazhong University of Science and Technology),Wuhan 430074,Hubei Province,China)

机构地区：[1]强电磁工程与新技术国家重点实验室(华中科技大学电气与电子工程学院),湖北省武汉市430074

出　　处：《中国电机工程学报》2023年第10期3904-3915,共12页Proceedings of the CSEE

基　　金：国家电网有限公司科技项目(5100-202199548A-0-5-ZN)。

摘　　要：新能源发电大规模接入电力系统使其出现了区别于传统电力系统的电流控制时间尺度的电压/频率动态现象。系统安全稳定运行所需的相对稳定的电压/频率水平与功率传输水平要求变换器并网设备具备基于端口功率调节内电势幅值/频率的机制。电网端电压状态检测的锁相控制方式复杂化了该调节机制,并为理解系统电压/频率动态过程机理带来障碍。然而,现有研究多直接基于物理连接关系对锁相环型并网设备进行数学描述,未能意识到功率激励-内电势幅值/频率响应关系是设备在系统动态过程中角色的一般化描述,更未能建立锁相控制方式对此激励–响应关系的影响机制认识。为此,文中以锁相环型并网变换器电流控制时间尺度为对象,基于其在系统闭环因果动态过程中行为的认识揭示设备内电势幅值/频率独立受有功/无功电流调节的机制。然后,基于不平衡有功/无功电流及其独立决定的锁相误差分别经电流控制器与锁相环共同建立内电势矢量过程的认识,阐明内电势矢量旋转运动的形成机制与内电势频率调节的锁相影响机制。最后,进一步初步说明变换器设备在系统电流控制时间尺度频率动态过程中的角色。The large-scale integration of renewable energy generation has resulted in voltage/frequency dynamics at the timescale of current controllers that differ from those in traditional power systems.The voltage/frequency level and power transmission capacities required for safe and stable power system operation demand an internal voltage amplitude/frequency regulation mechanism under power excitation from grid-tied voltage source converters(VSCs).The terminal voltage detection-based phase-locked loop(PLL)used in VSCs complicates this regulation mechanism,making the voltage/frequency dynamic process of the system more difficult to understand.However,existing works typically characterize VSCs based directly on their physical connectivity,failing to provide a generalized description of grid-tied devices’role during power system dynamic process with power excitation and internal voltage amplitude/frequency responses.Furthermore,they fail to establish the influence mechanism of the PLL on the excitation-response relationship of the VSC.Therefore,taking the current control timescale of VSC as an example,this paper reveals the mechanism by which the internal voltage amplitude/frequency depend solely on the active/reactive currents.This is based on an understanding of VSC dynamic behavior during causal power system dynamic processes.Then,based on the understanding that the internal voltage frequency is jointly established by unbalanced active/reactive currents as well as the phase-locked error it solely determined,the formation mechanism of the rotational motion of the internal voltage vector and the influence mechanism of the PLL on internal voltage frequency dynamics are clarified.Finally,the role of the VSC in frequency dynamics at the current control timescale of the system is preliminarily explained.

关 键 词：变换器并网设备 电流控制时间尺度 锁相环 有功/无功电流 内电势幅值/频率 激励–响应关系 

分 类 号：TM46[电气工程—电器]