Efficient Simulation Modeling Method for Full-Bridge Cascaded Multilevel Converter

Abstract

The invention relates to a high-efficiency simulation modeling method for a full-bridge cascaded multilevel converter, belonging to the technical field of power transmission and distribution. The core of this method is to equivalent the sub-modules and bridge arms of the full-bridge cascaded multilevel converter with the Dommel equivalent calculation model. The issue of the conduction state changing between two simulation instants is handled with additional switching devices. The method of the invention reduces the amount of calculation in the simulation operation by reducing the number of variable impedance branches in the electromagnetic transient simulation software, thereby making the simulation of the full-bridge cascaded multilevel converter efficient. The principle of the method of the invention is clear, and the calculation result is stable and reliable.

Description

technical field [0001] The invention relates to a high-efficiency simulation modeling method for a full-bridge cascaded multilevel converter, belonging to the technical field of power transmission and distribution. Background technique [0002] For the sake of sustainable development, using renewable energy such as solar energy and wind energy to generate electricity has become the development direction of the future power system. These power generation methods have the characteristics of being far away from the main grid and fluctuating greatly over time. The flexible DC transmission system is based on the Voltage Source Converter (Voltage Source Converter, VSC) and Pulse Width Modulation (Pulse Width Modulation, PWM) technology (Pulse Width Modulation, PWM) to invert the DC voltage into an AC voltage with controllable amplitude and phase, and can independently and quickly control all The transmitted active power and reactive power greatly enhance the flexibility of power ...

AI Technical Summary

Problems solved by technology

In the algorithm of the current general-purpose electromagnetic transient simulation software (ElectroMagnetic Transient Program, EMTP), the switching device is equivalent to a two-state variable resistor. Therefore, if a detailed device model is used in the simulation research, each simulation At any time, there are many equivalent calculated admittances of power electronic switching device branches that need to update the state, which will cause a large number of rows of the node admittance matrix to be re-triangulated at each simulation time, and in order to eliminate It is necessary to interpolate the state variables at the exact switching time, which will cause the simulation speed of the full-bridge cascaded multilevel converter model to be very slow. The device model simulates the full-bridge cascaded multilevel converter model of the practical engineering cascade level, and the simulation time will be almost unacceptable

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