基于自适应虚拟电阻的低压微电网多阻性逆变器下垂控制策略

摘要

低压微电网线路阻抗以阻性为主的特点,影响了下垂控制策略的性能.为解决问题,首先通过电压、电流双闭环控制参数将逆变器等效输出阻抗设计成阻性,然后引入虚拟电阻,改善线路参数,以适应P-V、Q-f下垂控制.逆变器加入虚拟电阻之后,削减了功率之间的强耦合;但系统电压降落也会大为增加.因此,给虚拟电阻增加自适应环节,使其取值随母线电压幅值波动不断地调整,因而能够减小母线电压偏差,保证系统的稳定运行,提高微电网的供电质量;并有效抑制系统环流.最后,通过MATLAB/Simulink搭建仿真模型,仿真结果验证了所提控制方法的正确性和有效性.%The performance of droop control method is affected by resistive circuit impedance of low-voltage microgrid, and the solutions are proposed.The voltage and current dual-loop proportional control method is designed to implement resistive output impedance.The line parameters can be improved by introducing virtual resistance,then be fitted to P-V, Q-f droop method.However, the strong coupling between active and reactive powers is weakened, but it may contribute to large voltage drop.Based on self-adaptive link, the value of virtual resistance is adjusted adaptively with the change of bus voltage magnitude, so that the stability performance and power quality of the microgrid will be increased, and the adverse efforts of virtual resistance will also be reduced.Moreover, case studies are conducted to verify the correctness and effectiveness of proposed control strategy.