基于虚拟角急动度并网控制策略

Grid connected strategy based on virtual angular jerk

提出一种基于虚拟角急动度的并网控制策略,这种控制策略结合了下垂控制和虚拟同步机控制的优点.虚拟角急动度控制是模拟物理运动中的加速和减速过程,当电网频率或者负载出现瞬时波动时,并网逆变器频率调节按照给定频率加速和减速曲线变化,使得并网控制拥有和虚拟同步机一样的惯性和阻尼特性.对比分析下垂控制、虚拟同步机控制和虚拟角急动度控制的传递函数,说明虚拟角急动度不仅具备惯性环节,并且其动态调节时间是可量化的.通过状态方程的稳定性分析,验证虚拟角急动度拥有良好的稳定性能.仿真实验结果表明,虚拟角急动度控制算法在负荷波动时具有良好的惯性和阻尼特性,能有效抑制微网频率的波动,并确保微网的可靠运行.

This paper presents a grid control strategy based on virtual angular jerk(VAJ), which combines the advantages of droop control and virtual synchronous generator(VSG) control. The VAJ can mimic the acceleration and deceleration process of physical motion. Thus, while handling the instantaneous fluctuation on the grid frequency or load, the inverter in the proposed approach can adjust the output frequency corresponding to the reference acceleration and deceleration curve to obtain the same inertia and damping characteristics as the synchronous machine. The transfer functions of droop control, VSG control and VAJ control are compared and analyzed, which indicates that the VAJ has inertia and the reponse time is adjustable. Through the stability analysis of the equation of state, the VAJ control strategy has excellent static stability performance. Finally, the simulation experiment verifies that the VAJ control strategy has excellent transient and dynamic performance when the load or power grid frequency fluctuates, which can effectively suppress the fluctuation of micro grid and ensure the operation reliability of micro grid.