基于虚拟阻抗的改进型微电网下垂控制策略

Improved Droop Control Strategy of Micro-grid Based on Virtual Impedance

通过对传统下垂控制算法的有功、无功分析,引入虚拟电感的电压电流双环控制策略,虚拟电感使逆变器等效输出阻抗成感性,从而通过调节感抗匹配程度提供功率均衡效果;提出一种多逆变器并联运行的改进型下垂控制算法,通过改进型下垂控制参数设置,减弱了阻抗对环流的影响。实验仿真结果表明,改进型多逆变器并联的微电网下垂控制算法提高了多逆变器的并联运行性能,有效地减小了多逆变器并联运行的环流问题,大大提高了多逆变器并联运行的无功均衡效果。

For multi - inverler parallel operation in micro - grid, the output impedance of inverlers and the line impedance between the inver/ers and point of common coupling are always different, which can result in big circulating current and lower precision of power sharing among inver/ers. Through the analysis of active and reactive power of traditional droop control algo- rithm, the voltage and emTent double - loop control strategy is introduced. An improved droop control algorithm is proposed for nmlti - inverter parallel operation, and the influence of impedance on the circulation is weakened by the droop control parameters setting. The simulation results show that the improved droop control algorithm can improve the perfommnee of multi - inverter parallel operation, effectively reduce the circulating current problem of multi - inverter parallel operation, and also greatly improve the reactive power balance effect of multi - inverter parallel operation.