An Efficient Simulation Approach for Voltage Source Converters Based on Semi-Implicit Delay Decoupling

Due to the time-varying admittance matrix of the detailed electromagnetic transient model of voltage source converter, the simulation efficiency is low when simulating largescale power grids with a large number of new energy stations. Based on the semi-implicit delay decoupling principle, this paper proposes a decoupling model with a simple decoupling circuit, a constant admittance matrix, and the ability to consider the internal characteristics of the converter. Firstly, starting from the state equation of the VSC converter, the semi-step delay model of the VSC converter with the DC side capacitor not grounded is constructed by using matrix splitting and delay technology, achieving decoupling between the AC and DC sides. Then, by taking advantage of the mutually exclusive conduction characteristics of the upper and lower bridge arms of the VSC, the parameter calculation of the decoupling model is simplified, making the system admittance matrix constant and further improving the calculation speed. The simulation results show that the proposed method improves the calculation speed while maintaining high accuracy. Finally, the accuracy and rapidity of the semi-implicit delay decoupling model are verified through the VSC grid-connected system and the IEEE 14-node example.