Multi-objective Parameter Optimization of Multiple VSG and Droop Controlled Inverters for Grid-connected and Islanded Operation

摘要

The control parameter optimization for multi-inverter systems is a well-established research field. Particularly in multi-inverter systems the structure is very complex due to the control parameter count and distinction between islanded and grid-connected modes. Recent investigations mainly focus on the optimum parameters for one operation mode for Droop or Virtual Synchronous Generator (VSG) controlled inverters. This contribution proposes a multi-objective parameter optimization to extract a global optimum for both operation modes simultaneously. First, the full-order small-signal state-space models are formulated utilizing the Component Connection Method. Then, a selection methodology is proposed to determine the critical poles, which are further evaluated using an objective function to meet the design constraints. Finally, the particle swarm optimization (PSO) algorithm is adopted to solve the problem. The proposed parameter optimization framework is applied to an exemplary scenario of a three-inverter system with droop control and VSG in islanded and grid-connected mode. The results are validated with a real-time large-signal model.