The invention discloses a design method for a
multi media card (MMC) self-defining submodule based on a real time digital
system (RTDS) in the technical field of power
system running and control. The technical scheme is that the design method comprises building a submodule
equivalent model containing an
insulated gate bipolar transistor (IGBT), a bypass
diode, a
capacitor element, a bypass switch used for submodule control and protection and a bypass
thyristor element, writing programs of the self-defining submodule according to a program development language of Cbuilder, and achieving various running states of the submodule. The design method has the advantages that the provided self-defining submodule can accurately simulate a
simulation model composed of discrete components,
simulation precision is high, a carrier wave phase shift modulation strategy can be combined,
capacitance voltage-sharing of the submodule can be achieved without building a
capacitance voltage-sharing controller externally, and occupied resources of the controller are reduced. In addition, signals for representing submodule faults can be output in input end signals of the submodule so as to be used for testing a control protecting device of the submodule.