Reseach On The Design Of DC/DC Converter With MPPT And Pv Parallel Connecting Modules

Solar energy is a type of clean energy. Solar cell takes on current-voltage (I-V) characteristic which is affected by the radiation and the temperature. The system samples the current and voltage of solar cells to control the duty of DC/DC converter. To obtain the maximum power from the solar cells, it changes the loads of the PV converter.In all MPPT algorithms, according to the implementation and complexity, the Perturb and Observe method and the Incremental Conductance method are the most widely used. In this paper, the Perturb and Observe method is tested and verified by simulation. These algorithms will be realized on the hardware platform. Two algorithms are compared and analyzed with the dynamic response, steady-state response and efficiency. The Perturb and Observe method is not suitable for the rapidly changing situations. The false is analyzed in this case. The MPP points from the two methods produce the disturbance in the vicinity through theoretical analysis and calculation. Optimization of the sampling cycle can reduce the power disturbance radius and the energy loss in the steady state. A novel MPPT method is proposed in this thesis. The I-V plane is divided into two parts by a linear function. One part includes MPP and the other does not include MPP. The operating point quickly moves to the maximum power. Then the module switches to the Incremental Conductance method or the Perturb and Observe method. The novel MPPT method improves the dynamic response and efficiency of the system. This new scheme can be used in a variety of the conventional MPPT methods.In the stand-alone photovoltaic power system, the forward part contains multiple parallel Boost Maximum Power Point Tracking system. The back part is the single-phase full-bridge DC/AC converter. When the load demand is greater than or equal to the PV output power, the PV modules works in the MPPT mode. When the load demand is less than the solar power, the modules are realized in the MPPT or voltage stabilization mode to ensure the stability of the DC/AC converter. The hardware and software of all the PV modules are the same. It is easy to install and increase or decrease the modules according to the user's demand.