An Accelerated Model of Modular Isolated DC/DC Converter Used in Offshore DC Wind Farm

Abstract

Modular isolated dc/dc converter (MIDC) is the most important equipment in the offshore dc wind farm. However, the simulation of the accurate MIDC model consumes too much time, which makes it difficult to carry out further studies about this topology. In this paper, an accelerated model that can dramatically decrease the consuming time of the MIDC simulation is proposed. Through an in-depth analysis about the MIDC submodule (SM), the LLC series–parallel resonant converter, four equivalent mathematical models that can completely describe the operation modes of the SM are deduced. Thereafter, based on the fourth-order Runge–Kutta method, a detailed design procedure of the MIDC accelerated simulation model is given. Moreover, the influences of different discretization methods on the simulation accuracy and computational speed of the accelerated model are also studied. Finally, the initial simulation model, the nested parent–child simulation method-based simulation model, and the accelerated simulation model of the MIDC with different numbers of SMs are built in the PSCAD/EMTDC. The simulation results prove the effectiveness of the proposed accelerated model.