基于功率解耦的微电网改进下垂控制策略

An Improved Droop Control Strategy Based on Power Decoupling in Micro-grid

在中、低压微网中,线路存在较高阻感比,无法满足传统下垂控制的控制条件。对此,提出一种修正相角的改进下垂控制策略,通过将引入的转换矩阵用于功率变换中,构造出具有统一旋转角的下垂控制器,保证了系统在拥有高R/X值的线路下微源逆变器输出有功功率和无功功率的解耦。利用Matlab/Simulink仿真平台搭建了两台逆变器并联的微电网仿真模型,将线路参数与逆变器接入情况不同的多种仿真结果分别与基于虚拟阻抗改进下垂控制的仿真结果进行对比,结果表明,提出的改进下垂控制策略解决了系统输出功率耦合的问题,且实现了功率合理分配。

In medium and low voltage micro-grid,the line has high resistance inductance ratio,which can not satisfy the condition of traditional droop control.In this paper,an improved droop control strategy with modified phase angle is proposed.By introducing the conversion matrix into power transform,a droop controller with a uniform rotation angle is constructed to ensure that the system outputs active power and reactive power of the micro source inverter are decoupled under the line with high R/X value.The simulation model of two parallel inverters in micro-grid is built by using Matlab/Simulink simulation platform.The simulation results with different line parameters and inverter access conditions are compared with those with improved droop control based on virtual impedance.It shows that the improved droop control strategy solves the problem of power coupling,and the output power is allocated reasonably.