This paper proposes an adaptive synergistic control strategy for a hybrid AC/DC microgrid to overcome its vulnerability to notable grid impedance variation provoked by load changes. Microgrid employs an internal DC link incorporating hybrid renewable resources represented by wind turbine generator, photovoltaic arrays and hybrid energy storage system. The latter comprises supercapacitor stacks for fast compensation and a hydrogen management scheme for long-term energy storage to counteract renewable resources indeterminacy. The internal DC link is attached to the AC side via a grid-side converter to constantly realize bus voltage and frequency constancy. The central premise of the proposed strategy during normal conditions is to meet load obligation via proper sharing of demanded power among hybrid resources and storage systems, optimize operation schedule of hydrogen management scheme to guarantee longer lifetime, enhance microgrid stability against abrupt loads disconnections when load shedding is activated during extremely low microgrid production. Accordingly, grid-side converter control structure is adaptively modulated based grid impedance estimation at the AC side in response to load manipulations to alleviate its impact on AC bus voltage stability. Furthermore, two series-connected resistive-type super fault current limiters are attached at the AC bus to mitigate large transient currents caused by different faults. The simulation results, so extensively obtained, reveal seamless exchange of desired load power during entire operational modes and decrease of bus voltage perturbations caused by extensive load variations thus enhancing microgrid robustness against parameters uncertainty. In addition, microgrid is maintained connected and protected during severe symmetrical and asymmetrical faults.

本文提出了一种用于混合 AC/DC 微电网的自适应协同控制策略，以克服其易受负载变化引起的显着电网阻抗变化的影响。微电网采用内部直流链路，结合以风力涡轮发电机、光伏阵列和混合储能系统为代表的混合可再生资源。后者包括用于快速补偿的超级电容器组和用于长期储能的氢管理方案，以抵消可再生资源的不确定性。内部直流回路通过网侧变流器连接到交流侧，以不断实现母线电压和频率恒定。在正常条件下，所提议策略的核心前提是通过在混合资源和存储系统之间适当共享所需功率来满足负载义务，优化氢气管理方案的运行计划以保证更长的寿命，增强微电网稳定性，防止在微电网产量极低时激活减载时突然负载断开。因此，响应于负载操纵，在AC侧基于电网阻抗估计自适应调制电网侧转换器控制结构以减轻其对AC总线电压稳定性的影响。此外，在交流总线上连接了两个串联的电阻式超级故障限流器，以减轻由不同故障引起的大瞬态电流。得到如此广泛的模拟结果，揭示了整个操作模式期间所需负载功率的无缝交换，并减少了由广泛负载变化引起的总线电压扰动，从而增强了微电网对参数不确定性的鲁棒性。此外，在严重的对称和不对称故障期间，微电网保持连接和保护。