基于干扰观测器的低压交直流混合微电网互联变流器反步控制策略

In a low-voltage hybrid AC/DC microgrid, a novel power outer loop control strategy with action threshold is proposed for interlinking converter, which can realize the appropriate distribution of the global load power according to the rated capacity of the subgrids and prevent the interlinking converter from frequently switching operation mode due to small disturbance effectively. On the other hand, the power fluctuations caused by load changes or the output power changes of distributed generation units, as well as the modeling errors of interconnected converter systems, are taken into consideration, and the time-domain mathematical model of interconnected converters with equivalent perturbation term is derived based on stationary frame. The backstepping control based on disturbance observer is proposed to suppress the influence of disturbance term and enhance the robust stability of the microgrid system, which can improve the dynamic response of the interlinking converter under external disturbance. Eventually, the effectiveness of the proposed control strategy is verified in the simulation model of a typical hybrid AC/DC microgrid. The results show that hybrid microgrid can share global load power proportionally with satisfactory dynamic response performance via the proposed control strategy.