Interpolation for power electronic circuit simulation revisited with matrix exponential and dense outputs

With a high penetration of power electronic equipment, transient simulation for power electronic circuit has been a main challenge for performance improvement of the electromagnetic transient simulation tools. In this paper, two new solvers for the matrix exponential-based simulation method are proposed based on the dense output formula and Padé approximation of different orders. The proposed solvers are implemented with the optimal combination of numerical integration method and interpolation method. Both solvers are L-stable. One has 3^rd-order accuracy which is more accurate than existing simulation tools in power electronic simulation. The other solver achieves 1^st-order accuracy with a lower precision numerical integration method than the same-order algorithms and is appealing from computation speed perspective. Numerical studies including TCR circuit and two types of VSC-HVDC systems are conducted to demonstrate the effectiveness of the proposed solvers.