Research On Solar Cells Maximum Power Point Control Algorithm And Grid-connected Inverter

The current solar energy technology is developing rapidly within the world, but the system inefficient, high cost of photovoltaic power generation is still the universal constraints is an important factor. To solve this the problem, For output of solar cells made accuratemeasurement of the purposes of solar cells series resistance in order to get theapproximate expression and the measured data processing computer software Mathematica,and obtain the series approximate expression of resistance. On this basis, the result of previous studies based on the establishment of new solar cells equivalent model and simulation software in Matlab and obtained good results. For the back of maximum power point tracking and accurate solar cell the basis for the virtual model.Second, From improving the efficiency of photovoltaic inverter, for the existing maximum power point tracking control method comparison, the maximum power point tracking (MPPT) control method, the proposed the power disturbance and INC method is that the phenomenon of shortcomings. Through the boost circuits simulation, Boost circuit that can take advantage of the duty cycle of switching device power output of solar cells to regulate,so that the output of solar cells will power the with the output voltage curve in the past, convert the output duty cycle with the switching device the power curve. Then proposed a fuzzy control, fuzzy control to control the boost circuit switching duty cycle to adjust the power output of solar cells. Fuzzy control in response speed than the first two methods have a great advantage, and in the Matlab/ simulink environment to established the corresponding simulation model, Preliminary experiments have made progress.At the last, on the grid-connected inverter control technology, the use of not continuous modulation SPWM to replace the traditional SPWM modulation to control the inverter.so that switching losser can be reduced by half, doubling the life of switching devices,electromagnetic interference reduced by half, and analyzed by using Fourier transformtraditional SPWM modulation output of the different, In which the same two fundamental, but slightly different harmonic characteristics. Also in terms of switching frequency hysteresis current control with the traditional methods were compared, still has a distinct advantage. Simulation results are consistent with the requirements of same frequency and phase, the current total harmonic distortion THD meet international standards. Finally, take active frequency drift method of islanding detection of grid-connected inverter has been studied, and achieved very good results.