改进VSG和下垂控制双驱动的孤岛微电网稳定运行控制策略

Control Strategy for Stable Operation of Islanded Microgrid with Dual-drive of Improved VSG and Improved Droop Control

针对孤岛微电网频率和电压在传统控制方式下难以保持稳定的问题,提出一种改进虚拟同步发电机和下垂控制双驱动的稳定运行控制策略。首先,在传统下垂控制中引入耦合补偿和虚拟阻抗,提出一种改进下垂控制策略;将辅助惯性加入虚拟同步发电机调速单元中提供惯性响应,并结合有功功率频率环路附加功率提出一种改进虚拟同步发电机控制方法;然后,基于电压同步控制器和双环控制器提出两种改进控制方法优势互补的暂态稳定性综合控制策略;最后,通过仿真和实验分析结果验证了本文所提控制方法和切换策略在负荷大扰动情况下的有效性,为后续微电网稳定运行控制提供借鉴。

Aimed at the problem that the frequency and voltage stability of isolated microgrids are difficult to maintain by using the traditional control methods,a control strategy for the stable operation of islanded microgrid with dual-drive of improved virtual synchronous generator(VSG)and improved droop control is proposed in this paper.First,coupling compensation and virtual impedance are introduced into the traditional droop control to formulate an improved droop control strategy.Then,auxiliary inertia is added into the VSG speed control unit to provide inertia response,and an improved VSG control method is formed by combining the additional power of active power frequency loop.Furthermore,an integrated control strategy for transient stability is put forward based on a voltage synchronous controller and a dual-loop controller with complementary advantages of the two improved control methods.Finally,through simulations and experimental analysis,results verified the effectiveness of the proposed control method and switching strategy in the case of large load disturbances,providing a reference for the subsequent control of stable operation of microgrids.