High-Performance Adaptive Control for Inverter-Based Residential Microgrids

Power electronics interfaced Microgrid becomes the major trend of residential power systems. In this paper, a residential microgrid including a solid state transformer (SST), distributed generators (DG) and variable loads is presented. To improve the reliability and flexibility, DGs are connected in parallel to feed the residential loads, and meanwhile, inject real power to the medium voltage (MV) distributed grid and the local dc Bus through SST. The SST is working at the current control mode while the ac bus voltage is regulated in a sharing way through the DGs. However, an SST can fail in the event of any fault due to the limited overcurrent rating of the switching devices. Aging of dc capacitors makes the dc Bus short fault a major one. Fast bus voltage restoring thus becomes a challenging target. Due to the physical differences and interactions of DGs, the wide range of operating conditions, as well the requirements of urgent disconnection, advanced control algorithms have the superiority of realizing high performances, i.e. fast bus voltage restoring and accurate load sharing. In this paper, a backstepping based adaptive controller is presented. Adaptive laws are designed to compensate for the unknown parameters within the system dynamics. Convergence and boundedness of the signals in the closed-loop control system are demonstrated through rigorous Lyapunov-based stability analysis. Moreover, a low-bandwidth synchronization guarantees the distributed implementation of this algorithm. Simulation results and experimental results are presented and have demonstrated the effectiveness of the proposed algorithm regarding both the grid-interacted mode and the standalone mode.