Research On The Application Of Islanding Effect Detection And Fault Tolerance In Photovoltaic Grid - Connected Power Generation System

With the rapid development of new energy power generation technology, the application of Photovoltaic Grid Connected Power Generation technology is more and more widely. The Isolated Island effect of the Photovoltaic Grid Connected Power System can damage the inverter system and the power equipment, which threatens the life safety of power maintenance personnel and so on. This paper makes a deep analysis and research on the application of The Isolated Island effect detection and Fault Tolerant Control Technology of Photovoltaic Grid Connected Power Generation System.Firstly, the offset method of frequency and the positive feedback frequency was analyzed in detail. The simulation analysis of their detection blind zone was carried out by using MATLAB.Secondly, The Isolated Island effect detection of single phase Photovoltaic Grid Connected Generation System was analyzed and designed, the design of the hardware circuit and software program based on MSP430F5529 microcontroller. Inverter topology selected voltage source input, current source output transformer isolation type. Hardware circuit was divided into inverter circuit, isolation drive circuit, signal sampling circuit and MSP430F5529 MCU peripheral circuit. The software program included A/D sampling module, liquid crystal display module, Fault Tolerant Control module, SPWM control module and island detection module. The Fault Tolerant Control technology was added in the signal sampling section. Compared with the non Fault Tolerant Control of PV Grid Connected Power Generation System, it could effectively reduce the occurrence of miscarriage of justice and leakage.Finally, a single phase analog Photovoltaic Grid Connected Generation System was established, on the basis of which a comparative study on Islanding detection and Fault Tolerant Control technology was applied to the system as the experimental platform. The detection time of the Holzer sensor detection signal, the power switch control signal, the output voltage and current of the inverter, the detection time of The Isolated Island effect under different parameters was measured, as was the FFT harmonic analysis of the output current of the inverter. It shows that given parameters of the feedback frequency shift method is suitable, and the islanding detection time conforms to the national standards; the fault tolerance control technology module works properly, which can ensure the reliability of the system, total harmonic content of the output current caters to national standards for Grid Connected.