基于MMC-SST的楼宇微网架构及其控制策略

A Building Microgrid Architecture Based on MMC-SST and its Control Strategy

传统的楼宇微网架构采用常规电力变压器接入电网,这种形式已经逐渐不能适应楼宇微网中分布式电源和敏感性负荷增多的趋势。由此,提出了一种基于模块化多电平变流器型固态变压器(modular multilevel convertersolid state transformer,MMC-SST)的新型楼宇微网架构。该架构中MMC-SST具有体积较小、可控度高、交直流接口兼具等优势,不仅能协调楼宇微网和配电网之间的能量流动,还能改善系统的电能质量,更符合楼宇微网的发展需求。MMC-SST的基础级采用了内模控制(internal mode control,IMC)方法,其简洁性、可调控性和鲁棒性均优于传统的基于dq解耦的PI控制。仿真结果验证了该楼宇微网架构在电能质量治理方面的优越性,其内模控制策略相对于PI控制具有更快的响应速度和更强的抗扰动性。

In traditional building microgrid architecture, conventional power transformer is used for connecting to power grid. However, this architecture is unable to adapt to the development of building micorgrid with increasing distributed power supplies and sensitivity loads. Therefore, a novel architecture of building mocrogrid was presented in this paper, which is based on modular multilevel converter-solid state transformer （MMC-SST）. Comparing with conventional power transformer, MMC-SST is relatively small, highly controlled and has both DC and AC interfaces, so it is able to coordinate the power flow between building microgrid and distribution network, and improve the power quality of system. In this way, the proposed architecture is more suitable for the development requirements of building microgrid. Additionally, internal mode control （IMC） method was applied at the stage control of MMC-SST, and the simplicity, controllability and robustness of this method are better than the traditional PI control based on dq decoupling method. Simulation results verified the superiority of the proposed building microgrid architecture in power quality control, and also demonstrate the advancement of IMC strategy in response speed and anti-disturbance ability comparing with PI control.