多VSG并联组网下的功率分配策略研究

摘要

虚拟同步发电机(VSG)控制算法能够模拟传统同步发电机的外特性,控制逆变器为大电网提供电压和频率支撑,以及相应的惯性和阻尼特性,使得大电网的稳定性得到提高.基于孤岛微电网下的VSG虚拟阻抗的双闭环控制策略,在外环中引入励磁调节器,考虑实际导线参数,提出一种多VSG并联组网下的功率分配策略,通过搭建两台不同容量的VSG并联系统仿真模型,实现VSG在并网下按照额定容量比进行功率分配.经过实验验证,多VSG并联下的功率分配策略可以实现离/并网运行模式的无缝、平滑切换,有较好的可行性与适用性.%Virtual synchronous generator(VSG) control algorithm can simulate the characteristics of the traditional synchronous generator,inverter with control can provide the voltage and frequency support for large power grid,and the corresponding inertia and damping characteristics,improving the stability of large power grid.In this paper,an excitation regulator is introduced into the outer ring based on double closed loop control strategy of VSG virtual impedance under islanding micro grid.Taking into account the actual wire parameters,this paper proposes a multi VSG parallel network power allocation strategy,by setting up two simulation models of VSG parallel system with different capacities,the power allocation of VSG under the grid connected capacity according to the rated capacity ratio is achieved.Experimental results show that the power allocation strategy in parallel with multi VSG can achieve seamless and smooth switching of off/grid operation mode,and has better feasibility and applicability.