Fully Fpga-Based Implementation Of A Modified Control Strategy For Power Electronic Transformer In Railway Traction Applications

Due to its several advantages (especially low volume and weight), power electronic transformer has gained notable attraction in railway applications. The main focus of this work is devoted to development a fully filed programmable gate array (FPGA)-based control platform for power electronic transformer in the aforementioned application. Due to the parallel processing of FPGAs that results in a faster control algorithm execution, reliable operation (which is of major importance in traction applications) is guaranteed. For this purpose, an input series output parallel power electronic transformer structure is built, and various considerations for reliable and stable operation of the power electronic transformer in traction applications, such as safe start-up and bidirectional power flow, along with the required control and pulse generation schemes, have been designed and implemented in a Xilinx FPGA control platform. Moreover, a modified control algorithm is proposed for controlling the power electronic transformer in a simple and more reliable manner. This control scheme is developed based on the output voltage of the DC-DC-LLC resonant converter, and can effectively control the sum of rectifier DC-link voltages and track the input sine reference current, with a lower number of required sensors. Finally, the effectiveness of the proposal has been tested from various aspects by experimental tests.