An ADC Switch Model Based on Root Matching Method in Electromagnetic Transient Simulation for Power Electronic System

ABSTRACT The associated discrete circuit (ADC) switch model has the advantages of fixed equivalent admittance matrix and high real‐time simulation efficiency, making it one of the main switch models in electromagnetic transient simulation. However, the virtual power loss during the switch state transition of ADC model severely affects simulation accuracy. To eliminate virtual power loss, an ADC switch model based on root matching method is proposed. Firstly, determine stability by analyzing the pole distribution of the Z‐transform to select the switch structure. Secondly, the root matching method is used to discretize the switch model, while model parameters are determined based on steady‐state and transient‐state characteristics. Finally, by analyzing the mechanism of virtual loss generation, a constant initialization technique is proposed to calculate history current under different switch states. Taking two‐level voltage‐source converter as the experimental object, a real‐time simulation hardware platform is built to verify the feasibility of the proposed model. Simulation results show that compared with the traditional or improved ADC switch model, the virtual power loss of the proposed switch model can be reduced by 57% to 96%, the model oscillation duration can be decreased by 7% to 38%, and the constant initialization technique can completely eliminate the virtual power loss.