Simulation method of MMC (modular multilevel converter) and application thereof

Abstract

The invention discloses a simulation method of an MMC (modular multilevel converter). The simulation method comprises the following steps: (1) obtaining operation parameters of an SM (Submodule); (2) construction an equivalent circuit of SM; (3) establishing an artificial circuit of SM; and (4) establishing a simulation system of MMC and simulating the system. According to the simulation method provided by the invention, by the utilization of numerical calculation and electromagnetic simulation internal mechanism, the SM in the MMC can be equivalent to a simple branch formed by a controlled voltage source and an adjustable resistor effectively, and the number of nodes of the system and the corresponding simulation calculation can be greatly reduced, so that on the premise that the simulation precision is ensured, the simulation speed of the MMC is greatly promoted, and the method is applied for MMC design.

Description

technical field [0001] The invention belongs to the technical field of power system simulation, and in particular relates to a simulation method and application of MMC. Background technique [0002] MMC (Modular Multilevel Converter, Modular Multilevel Converter) is a relatively new topology type of voltage source converter. The basic unit of its topology is a half-bridge submodule (Submodule, SM) or full bridge submodule. In recent years, with the emergence of more novel MMC topology and the continuous development of its control methods, the voltage level and power transmission capacity of MMC have been greatly improved, which makes the high-power flexible HVDC transmission become the future development. trend. Different from the traditional DC transmission topology based on thyristors, the turn-on and turn-off of MMC’s modular power electronic devices are realized by trigger signals passing through the device gates; by using appropriate circuit topology and switch modula...

AI Technical Summary

Problems solved by technology

Too many SMs will pose a great challenge to the simulation modeling of the converter; even if the simulation modeling can be successfully completed, as the number of SMs increases, the time required for the power system electromagnetic transient simulation tool to simulate will decrease. A substantial increase, which brings great inconvenience to simulation research and engineering design

The reasons for the slow simulation speed of the multi-SM system are as follows: (1) The increase in the number of switching devices will cause a large change in the structure of the system every moment, which increases the time for the software to obtain the system matrix; (2) ) Power system electromagnetic transient simulation software for one-step simulation, the software needs to iteratively solve the system, the solution process includes a process of inverting the entire system matrix, however, the scale of the system matrix is ​​positively correlated with the number of nodes in the system; Therefore, more SMs mean that the system contains more nodes, and more nodes mean that the scale of the system matrix will become larger, and the computer system has to consume more time for large-scale Generation of system matrix and operation of inversion

Images