Economic Optimization Control Method of Grid-Connected Microgrid Based on Improved Pinning Consensus

Abstract

For the sake of reducing the total operation cost of grid-connected microgrids, an improved pinning consensus algorithm based on the incremental cost rate (ICR) is proposed, which defines ICR as the state variable. In the algorithm, the power deviation elimination term is introduced to rapidly eliminate the total power deviation, and the pinning term is brought to realize the fast convergence to reference value. By computing the optimal ICR of the system, the optimal active output reference value of each distributed generation (DG) is obtained when the system realizes the economic optimization operation. In addition, an economic optimization control method of grid-connected microgrids, based on improved pinning consensus, is proposed. By utilizing the method, the economic optimization operation of the system is attained by basing on the established distributed hierarchical architecture and by sending the reference value of optimal active output of each DG to the P-f droop control loop. Finally, a simulation model of parallel operation system of six DGs is established. The impact of grid electricity price, pinning coefficient and other factors on the operation state of the system is analyzed and simulated. The simulation results show that the economic distribution of active output is completed. The proposed method can make the microgrid rapidly enter the economic optimization state, and can still reduce the total operation cost and possess the faster response speed under the conditions of changing electricity price, low algebraic connectivity topology, DG plug-of-play, dynamic line rating (DLR) constraint, etc.