Simulation of Modular Multilevel Converter System Via an Analytical Approach

Conventional numerical integration based simulation methods for modular multilevel converters (MMCs) need small integration time-steps to ensure simulation accuracy, which leads to a huge computation burden and limits the simulation speed. An analytical approach is proposed in this paper to reduce the computation burden and improve the time performance. Between any two adjacent switching moments, the MMC can be modeled by linear ordinary differential equations which can be quickly solved via eigenvalue decomposition techniques. A single phase 3-level MMC is used to test the proposed analytical approach and compare it with the Euler forward method in terms of simulation accuracy and computation time. The result shows that the analytical approach can greatly reduce the computation burden and simulation time without much trade-off in simulation accuracy.