Maximum Power Point Tracking And Anti-islanding Operation Control Of Photovoltaic Grid-connected Systems

Recent yeas, the problems of environmental pollution and exhaustion of energy sources become worse. In order to sovle these problem, the role of photovoltaic (PV) generation system is gradually changed from supplemental energy to substitute energy, and the grid-connected photovoltaic generation has been a hot spot that more countries study and develop. The main purpose of this paper is to design one set of the grid-connected photovoltaic system based on DSP TMS320F2812.This paper focuses on single-phase grid-connected photovoltaic system, and deals with such important problems as maximum power point tracking (MPPT) of PV array, the control of inverter output current wave form and anti-islanding effect by establishing related simulation models, and introducing related control method. Finally, the result of experiment validates the feasibility of control method. The more details about research contents are as follows:1. According to the mathematical models of solar cell, the PV array simulation modules is built, and MPPT simulation experiment is done. The simulation characteristic curves are same as real PV characteristic. Then the control circuit is designed using AVR microcontroller and CPLD, through which the control circuit to generate a varying duty cycle and 40 KHz PWM pulse to control High-gain Boost circuit. Algorithm uses the incremental conductance method. Experiments show that maximum power point tracking effect is good.2. The topology of grid-connected PV system is introduced. The principle of grid-connected and two direct current control methods are analyzed. Then, the regulator parameters of voltage loop and current loop are designed. The control method can keep the current frequency and phase synchronous to the grid.3. The main circuit, control circuit and program soft based on the DSP TMS320F2812 are completed. Experimental result shows the inverter can work reliable at grid-connected mode, and the experimental wave form are given at last.4. Some detection methods of anti-islanding effect are introduced, and the corresponding simulation model under Matlab/simulink environment based on Active Frequency Drift (AFD) is established. The simulation wave is given.5. In the last of the paper, all work of the single-phase grid-connected PV system are listed, and the future research plan of the grid-connected PV system is presented.