内嵌同步机支撑特性的含储能并网变流器电流型控制策略

Current-based Control Strategy for Grid-connected Converter with Energy Storage and Embedded Synchronous Generator Support Characteristics

光储并网变流器具有低惯量、弱阻尼、调压能力弱和功率频繁波动等特征,大规模接入会影响电力系统安全稳定运行。针对此类含储能并网变流器,提出了一种内嵌同步机支撑特性的电流型控制策略,以增强系统的惯性支撑能力。该策略模拟同步机的动力学行为,将并网变流器输出外特性控制成具有同步机控制特性的受控电流源,融合了基于虚拟同步机的构网型控制与基于锁相环的跟网型控制两者的优势,在惯性支撑、故障穿越、电网谐波、孤岛运行等方面具备显著综合优势,并且虚拟惯性支撑的实现无须对系统输出频率微分进行检测采样,避免了频率微分检测带来的噪声干扰。此外,针对交流侧惯性支撑能力与直流侧电压稳定难以调和的矛盾,设计了兼顾直流侧电压稳定与交流侧惯性支撑的模糊自适应比例-积分(PI)协调控制策略。最后,硬件在环实验结果验证了所提策略的可行性和有效性。

The grid-connected converter with photovoltaic and energy storage has the characteristics of low inertia,weak damping,weak voltage regulation ability,and frequent power fluctuations.Large-scale integration of grid-connected converters with photovoltaic and energy storage will affect the safe and stable operation of the power system.For this kind of grid-connected converter with energy storage,this paper proposes a current-based control strategy with embedded synchronous generator support characteristics to enhance the inertial support capability of the system.This strategy simulates the dynamic behavior of synchronous generators and controls the external characteristics of the grid-connected converter output to a controlled current source with synchronous generator control characteristics.It combines the advantages of grid-forming control based on the virtual synchronous generator and grid-following control based on the phase-locked loop,which demonstrates the significant comprehensive advantages in inertia support,fault ride-through,power grid harmonic,and islanding operation.The proposed strategy does not require detection and sampling of the output frequency differentiation of the system,which avoids noise interference caused by frequency differentiation detection.In addition,to address the irreconcilable contradiction between the inertia support capability on the AC side and the voltage stability on the DC side,this paper designs a fuzzy adaptive proportional-integral(PI)control strategy to coordinate the voltage stability on the DC side and the inertia support on the AC side.Finally,the hardware-in-the-loop experimental results verify the feasibility and effectiveness of the proposed strategy.