Electromagnetic Transient Equivalent Model of Power Electronic Switch Based on Physical Intuition

At present, the permeability of power electronic devices in the power grid is increasing dramatically. To address the problems of time-varying admittance matrix of power electronic switch binary resistance model, low accuracy and high virtual power loss of associated discrete circuit (ADC) model in transient process, a constant admittance equivalent model based on physical intuition integrated integral exponential is proposed in this paper. In this model, the virtual resistance -RL is introduced into the conduction branch of the ADC constant admittance model to generate power to compensate for the virtual power loss caused by dynamic components. The analytical solution of the proposed equivalent branch was rationalized and simplified to construct the difference equation with exponential form, while the admittance matrix could be guaranteed to be invariant, thus improving the simulation efficiency. Besides, the cross-initialization method is adopted to further reduce the initial error of state switching. Based on the two-level voltage source converter (VSC) circuit, the optimal recommended parameters of the model are given by solving the spectral radius and analyzing virtual power loss of the proposed model. Simulation results confirmed that the proposed model has the advantages of low virtual power loss, high precision, high simulation efficiency, and no numerical oscillation problem.