摘要
针对风电、光伏等电力电子并网设备对系统支撑能力评估问题,核心基础是正确认识设备根据有功/无功功率不平衡调节内电势幅值/频率的功能性角色(设备特性)。然而电力电子设备主流的锁相并网结构严重阻碍了对设备功能性角色的认知,特别是目前业界普遍基于锁相并网的具体连接结构,形成了设备内电势跟随电网电压或端电压变化的“跟网”角色认知,尚未认识到系统运行中设备所应具备的功能性角色。为此,首先通过深入认识隐藏在锁相并网结构下内电势响应取决于电流单独激励的电流控制独立激励-响应机制,澄清了锁相并网设备通过有功/无功功率不平衡独立调节内电势幅值/频率的功能性角色,进而提出基于有功/无功功率不平衡激励-内电势幅值/频率响应关系即幅频运动方程的设备特性表征方法,最后通过阐述锁相并网设备特性由功率激励-内电势响应关系表征的必然性,指出当前业界对锁相并网设备特性认知的局限。
For evaluating the capacity of wind powers,photovoltaics and other power electronic grid-connected units supporting power systems,the core foundation is to correctly understand the unit’s functional role(i.e.,the unit characteristics)that unit adjusts its own internal voltage amplitude/frequency according to the active/reactive power imbalance.However,the mainstream PLL-based grid-connection structure in power electronic units seriously hinders the understanding of the unit’s functional role.In particular,based on a specific PLL-based grid-connection structure,the industry and academia at present form a“grid following”role perception that the internal voltage of unit follows the grid voltage or terminal voltage,and have not recognized the functional role that the unit should take during the system operation.Therefore,through an in-depth understanding of the independent excitation-response mechanism of current control which is hidden under the PLL-based grid-connection structure,i.e.,the internal voltage response depends on current excitation alone,the functional role of PLL-based grid-connected units in which the active/reactive power imbalance independently adjusts the internal voltage amplitude/frequency is clarified.Afterwards,a role characterization method for unit is pro-posed based on the relationship between active/reactive power imbalance excitation and internal voltage amplitude/fre-quency response,i.e.,the amplitude-frequency motion equation.Finally,the inevitability of characterizing the role of PLL-based grid-connected units through the relationship between power excitation and internal voltage response is elab-orated on,and the existing limitations in the understanding of the role of PLL-based grid-connected units in industry and aca-demia are pointed out.
作者
袁小明
王思成
贠阳阳
YUAN Xiaoming;WANG Sicheng;YUN Yangyang(School of Electrical and Electronic Engineering,Huazhong University of Science and Technology,Wuhan 430074,China)
出处
《电源学报》
CSCD
北大核心
2024年第5期1-14,共14页
Journal of Power Supply
基金
国家自然科学基金资助项目(U23B6008)。
关键词
锁相并网设备
功能性角色
特性表征
独立激励-响应机制
幅频运动方程
PLL-based grid-connected unit
functional role
role characterization
independent excitation-response mechanism
amplitude-frequency motion equation
