独立微网中多虚拟同步机功率精确分配控制策略

独立微网中,逆变器采用虚拟同步发电机(Virtual Synchronous Generator, VSG)控制模拟同步发电机运行机制,为微网提供惯性和阻尼,改善系统电压频率稳定性。但传统VSG并联系统不具备无功出力合理分配以及直流抑制的能力。首先,从VSG基本原理入手,分析了VSG功率均分机理。其次,为构造积分器,从电压补偿角度提出了一种改进的无功控制方法,实现了无功分配与线路阻抗解耦。在直流抑制方面,利用准谐振控制器重新设计了底层双环控制。同时研究了参数匹配方法,保证VSG功率均分。最后通过Matlab仿真验证了所提策略的正确性和有效性。

Accurate power sharing control strategy of multiple virtual synchronous generators in independent micro-grid

To provide inertia and damping for the system and to improve the stability of voltage and frequency in independent micro-grid, Virtual Synchronous Generator (VSG) control strategy of inverters is recommended, which mimics synchronous generators. However, the traditional VSG parallel system is challenged by rational distribution of reactive power and DC suppression. Firstly, the accurate power sharing mechanism of VSG is analyzed based on the principle of VSG. Besides, an improved reactive power control method is proposed from the angle of voltage compensation to construct the integrator, which can realize the decoupling of reactive power distribution and line impedance. Furthermore, the double loop control is redesigned to suppress the DC by using the quasi resonant controller. At the same time, the method of parameter matching is studied to ensure the accurate power sharing of VSG. Finally, the validity and effectiveness of the proposed VSG control are verified by Matlab simulation. This work is supported by Science and Technology Project of State Grid Corporation of China (No. JSDL-XLFW- SQ-2016-10-092).