Parallel multi‐rate simulation scheme for modular multilevel converter‐based high‐voltage direct current with accurate simulation of high‐frequency characteristics and field programmable gate array‐based implementation

Abstract

AbstractThe real‐time simulation of the modular multilevel converter‐based high‐voltage direct current (MMC‐HVDC) transmission system has become a popular research topic. However, in order to meet the real‐time performance, the real‐time simulation technology will cause additional simulation errors for MMC‐HVDC, especially on its frequency characteristics. Therefore, a parallel multi‐rate simulation scheme for MMC‐HVDC is developed in this work to ensure accurate simulation of high‐frequency characteristics. Firstly, a non‐error method based on converter transformer decoupling is proposed to decouple the converter and alternating current system; direct current transmission line decoupling and arm decoupling methods are used to achieve decoupling among and within converters. A multi‐rate data synchronous mechanism is established by considering the differences among high‐frequency characteristics caused by delayed data interaction. Secondly, the computing architectures of the primary system solver and modular multilevel converter controller are designed based on a field programmable gate array (FPGA). The real‐time simulation platform for a four‐terminal true bipolar MMC‐HVDC is constructed based on the FPGA array. Thirdly, the factors in multi‐rate simulation affecting the simulation accuracy of high‐frequency characteristics are analysed. The simulator is shown to be accurate in steady and dynamic states. The authors also verify its applicability for further research on high‐frequency resonance based on control experiments.