The Power Quality Monitoring Device Of Grid-connected Inverters

In nowadays, lots of power electrical devices and nonlinear loads are widely used. With improving the productivity, it causes severe deterioration of power quality. Among them, the application of grid inverters is already quite extensive, and inverters have a serious impact on the power quality of the public. The grid installation of power quality monitoring devices on inverters, which can monitor the power quality real-time, is of great significance.The significance of power quality detection is introduced first. Then the need for power quality detection is analyzed. The basic concept of power quality and related domestic and international standards for power quality detection is briefly introduced. The basic measurement principle and algorithm of various power quality parameters are studied in depth. National standards of power quality testing requirements of the design are defined. On the basis of the research above, one plan of power quality monitoring system is designed with Digital Signal Processors (DSP) as the core unit. The hardware and software of the system is illustrated in this Dissertation.In comparing today's variety of power quality analysis and combining with the actual parameters with inverters, Discrete Fourier Transition (DFT) is adopted in this system. The TMS320LF2407A is chosen as the Central control unit. The data sampled by the AD device of the inverter is transmitted by CAN bus. The results will be sent via RS-485 bus to the display unit using Modbus protocol.Based on the hardware design, the software is programmed using C language. The core algorithms and related software are designed on TMS320LF2407A.Finally, experiments on this system debugging are done. The feasibility and accuracy of the system is verified. The test results showed that the system works stably, and meets the requirements of power quality analysis. The system has good practical value.