Research On The Key Technology For Grid-Connected Inverter Based On FPGA And ARM

The fossil energy on the earth less and less, renewable energy becomes a kind of important ways to obtain reliable and continuous power. Grid-connected inverters which are the interface of grid and wind power generation, photovoltaic power generation and fuel cell power generation play an important role in distributed generations. For the good real-time interactive capability, 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. This paper studies the basic structure and control principle of three-phase grid inverter for grid inverter system, the mathematical model of the double closed loop. Through analysis, the modeling and simulation of Matlab/Simulink verified the rationality of the designed parameters.2. For power grid adaptability, the imbalance of power grid voltage amplitude and phase angle mutation, frequency fluctuation and harmonic interference caused by all kinds of common phenomenon caused by the phase locking problems, using SIMULINK software to build the unbalanced three-phase phase-locked loop simulation model, for SSRF PLL, DDSRF PLL, DSOGI PLL are compared; Structures, improvement based on the proportional integral resonance(PIR) of unbalanced three-phase phase-locked loop model, further validation of the proposed improved method is effective and feasible.3. Based on the FPGA platform, all function modules are designed for A/D sampling, 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.4. A dual core inverter controller based on the FPGA+ARM architecture is designed. 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, six-channel A/D sampling, 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.It can send operation parameters and other control instruction to FPGA through the embedded ?C/OS-II real-time operating system, to complete the interaction with the FPGA core board and the upper machine.5. 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.