Design and Implementation of a Low-Cost FPGA Based Real-Time Simulator for a Three-Phase Grid Emulator Including Neutral

This paper presents the design and the implementation of a low-cost FPGA-based real-time simulator for a grid emulation system including neutral. The real-time simulator for the proposed grid emulator is implemented in an open-loop version. No feedback mechanism or specific controllers are needed. That makes the design simple, low-cost, fast, and easy to implement while reducing the risk of system instability. The design process combines high-level Simulink models with HDL code generation and FPGA synthesis implementation in order to control the grid emulator. The control of the three-phase four-leg grid emulator is implemented using a PWM method based on a triangular carrier wave involving the concept of offset voltage to reach better PWM performances while reducing FPGA resource utilization. Experimental results carried out show the effectiveness of the proposed design that can track the reference with high precision, less than 1.6% of relative error compared to the reference, while achieving fast transient performance.