Research On Digital Control Platform For Modular High Power Electronic Equipments Based On DSP&FPGA

The power electronic equipment plays an important role in energy transformation of the industry, military, aerospace and other fields. In recent years, with the development of microelectronics, communication, computer technology and so on, high-capacity, high-power and high-reliability has become an important direction of the development of power electronic technology. Taking the grid system for example, VSC-HVDC, STATCOM and APF all contain the power electronic equipment with large capacity or ultra-large capacity (MW to hundreds of MW). These systems normally consist of dozens of submodules in serial and parallel with switching devices. They transform the electricity by the digital system's timing control of each submodule. In addition, with the increasing reliability and security of the grid, fault diagnosis and fault tolerant control has attracted more and more attention. Therefore, the control system for modular high-power electronic equipments not only need outstanding mathematical ability and control ability, but also need the real-time monitoring of main circuits and the reasonable judgment of system fault. In view of the above requirements, the following works are carried out in this paperFirst of all, combined with the typical topological structure of power electronic equipment, the demand for digital control platform is analyzed. The high-power electronic equipment has the basic characteristics as follows:Modular and multilevel operation mode becomes more and more popular; Switch power supply replace the traditional linear power supply, becoming the main way of controlling the circuit; More submodules in serial and parallel needs more control signals; The importance of power electronic equipment requires outstanding real-time performance, reliability and fault tolerance. The basic hardware resource requirements such as the interface, computing and communication ability of the power electronic equipment are put forward, providing references for the selection and design of core chips.Secondly, the hardware and software of the digital control system is designed based on the demand analysis. We choose TMS320C28335 DSP and EP3C40 FPGA to be the core controller. To keep the stable communication between control system and other systems, such as monitoring system, the communication network is builded by CAN, RS232 and RS485. PWM duty ratio algorithm is analyzed by a intersectant-dot sampling method of SPWM with nonsymmetrical rules. The control program(main program, duty ratio calculation program, fault handling program and so on) of DSP is writed by C Language, and the universal PWM IP Core is designed in FPGA based on Verilog HDL. The system could provide sequential control for different circuit topology and cut off the failure module from the main circuit in time.Finally, hardware test, software simulation and comprehensive test with MMC verify the basic function of the digital control platform. The results show that the platform can provide reliable control scheme for the modular high power electronics equipments and play significant roles for further studies.