750-kW interleaved buck converter dc supply control implementation in a low-cost FPGA

The digital control of a 750-kW dc supply that converts a 480-V three-phase ac input voltage to an adjustable dc output voltage which has the maximum voltage value of 600 V is presented in this paper. Digital control is important for achieving precise data acquisition and proper operation of power electronic equipment. In addition to power semiconductor switching signals, several fault and warning signals from the power converter must be considered. Providing sufficient inputs/outputs (I/Os) and high-speed parallel processing, the field programmable gate array (FPGA) is one of the best candidates to accomplish the tasks mentioned above. In the proposed FPGA application, all functions including analog-to-digital conversion (ADC), power electronic converter algorithms, data interface, and protection logic for the dc supply are implemented in one single cheap FPGA which operates at a 25 MHz clock. All programming of the FPGA is completed by manual coding of hardware description language - the Very high speed integrated circuit Hardware Description Language (VHDL). A small-scale prototype is built and tested to provide further verification of the VHDL code prior to final implementation of the 750-kW prototype. The validity of control algorithms and FPGA functions are verified by simulations using Matlab/SimulinkTM Xilinx ISETM, respectively, prior to implementation in the hardware prototype.