Real-Time Simulation of Hybrid Three-Level and Modular Multilevel Converter Based on Complete Equivalent Model for High Voltage Direct Current Transmission System
23 Dec 2021
Jintao Han, Levi M. Bieber, Jared Paull, Liwei Wang, Wei Li, and Jean-Nicolas Paquin
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Real-time simulation is a crucial but complicated task for fast control prototyping of high-power converters. Detailed semiconductor device-based model simulates a large number of switching events at a small time step, which requires large computational effort and is thus challenging for real-time simulation. This paper proposes a complete equivalent model (CEM) approach for the real-time simulation of a hybrid 3-level and modular multilevel converter (H3LC). The presented CEM simplifies the detailed equivalent model (DEM) of the H3LC and facilitates the implementation of real-time simulation. A central processing unit (CPU) and field-programmable gate array (FPGA) based simulation is presented whereby the massive parallel computing power of the FPGA enables the simulation of the H3LC's three-level T-type converter and the hundreds of series-connected full-bridge submodules. The rest of the converter system, including the converter controls, the AC grid, and the measurement of the AC currents are implemented within the CPU model. The FPGA-based converter model is interfaced with the CPU model using controlled voltage sources to represent the AC- and DC-side equivalent voltages of the H3LC. The OP5700 real-time digital simulator from OPAL-RT Technologies is used to realize the CPU-FPGA real-time simulation, which is verified by the offline MATLAB/Simulink Simscape model.