Design And Implementation Of Three-Phase Grid-connected Inverter Based On FPGA+ARM Architecture

Some new features are appeared in grid-connected inverter because of the environmental concerns and the demand for energy. Thus the client terminals of the inverter are encouraged to adjust the power grid actively. In abroad, the client terminals are always supervised and controlled. So, actually, the power grid and the inverters must be provided with the good real-time interactive capability. For these new features and the growing trend, the paper designs the dual core inverter controller based on the structure of FPGA+ARM. By the designed controller, the inverter could perform the grid-connection function, and also be controlled real-time online.1. By analyzing the SVPWM modulation algorithm of three phase grid-connected inverter and the principle to control the grid-connected, the mathematic model of the grid-connected inverting system is built. And its reasonability is verified by simulation work in MATLAB.2. Based on the FPGA platform, all function modules are designed for A/D transforming, PI adjusting, the coordinate transforming, SVPWM and dead area setting, etc. The process the SVPWM pulse with dead area produced is focus to introduce. Furthermore, the logic time sequence is simulated by Modelsim tool to verify the validity of the program function.3. For the new features of the interactive grid-connected inverter, a dual core inverter controller based on the FPGA+ARM architecture is designed. In the controller, the tasks of the grid connection inverter are assigned in accordance with the real-time requirements. The FPGA communicates with AD and ARM through the SPI protocol. The ARM communicates with the upper computer through the MODBUS protocol. The functions with the higher demand for real-time such as algorithm operation and protection are arranged to the FPGA controller with high clock frequency and parallel computing ability. For example, multi-channel A/D sampling at 500 k rates, frequency and phase measuring module of grid-side, and so on. The tasks without the real time requirement, for example, the file management, the interactive man-machine interface and real-time monitoring function are arranged into the ARM controller, because it provides the strong ability to do the transaction management and task scheduling. ARM controller is the core of the whole control system. It can send operation parameters and other control instruction to FPGA through the embedded μC/OS-II real-time operating system, to complete the interaction with the FPGA core board and the upper machine.4. Through the small power electricity experiment with debugging and measuring the software programs and the controller, the waveform of the electrical parameter is obtained. The inverter modulation theory is verified. It shows the feasibility of our design work, which realizing the inverter power conversion function and real-time online monitoring function effectively.