System-on-chip implementation of embedded real-Time simulator for modular multilevel converters

The aim of this paper is to present the implementation of an Embedded Real-Time Simulator (ERTS) for Modular Multilevel Converters (MMCs), using low-cost System-on-Chip (SoC) platform. In order to achieve new functionalities such as sensor-less control, monitoring, diagnostic and fault detection, the MMC plant model can be implemented along with the controller. In MMC applications, the implementation of the RTS is particularly challenging due to the complex structure of the MMC and its stringent timing constraints, especially when the number of Sub-Modules (SMs) increases. In addition to the previous requirements, in case of ERTS, the hardware resources are also limited in order to keep low the cost of the entire controller. Moreover, the chosen device must also provide enough modulators for driving all the SMs and sufficient ADC interfaces for acquiring the capacitor voltages. For these reasons, a Xilinx Zynq SoC platform is adopted; this device provides two hard-processors along with the programmable gate array. In this work, the MMC plant model and the MMC controller are implemented in the two available microcontrollers, whereas, all the modulators and interfaces can be implemented in the programmable gate array. The achieved implementation is evaluated in terms of execution time and maximum allowable number of SMs. In order to validate the proposed implementation, HIL results for a single-phase MMC simulator are also provided.