The Research And Development Of A Single-phase Photovoltaic Grid-connected Inverter Based On Deadbeat Control

In the background of energy crisis and environmental pollution, development and utilization of alternative energy sources is around the corner. Solar energy is clean, renewable and abundant. The rational utilization of the solar energy is one of the effective way to solve the energy problem.As an effective way to use solar energy,PV power generation has received more and more attention.The PV inverter is the core of the PV power generation system, and its performance is critical to the whole system. Therefore, the research and improvement of the performance of PV grid-connected inverter has a very important practical significance. The paper studies and designs a3kW single-phase PV grid-connected inverter. The main contribution can be summarized as follows:1.Through the analysis and comparison of the topology of the typical PV grid-connected inverter, the inverter is determined using two-stage non-isolated topology. The former stage uses boost circuit to achieve the maximum power point tracking (MPPT), and the latter stage uses a single-phase full-bridge circuit to complete the grid-connected invert function.2.0n the basis of the PV cell characteristics and the algorithms of MPPT, a improved algorithm is proposed to solve the contradiction between the accuracy and rapidity of the perturbation and observation method. And the simulation results verify its effectiveness.3.On the basis of the establishment of the inverter control model, the shortcoming of the traditional double PI control strategy were pointed out and an improved strategy with the PI control in the voltage outer-loop and the deadbeat control in the current inner-loop is proposed. In order to reduce the influence of the delay of the DSP, a method of predictive deadbeat control is further proposed and the simulation results are also verified that it has good control effect.4.By comparing conventional islanding detection methods, the islanding detection scheme in this paper was determined. For reducing the impact of load property, a periodic perturbation of bi-directional active frequency drift method is proposed. The simulation results show that it has a good islanding detection function.5. The paper presents the hardware design and software flow chart, and a prototype is completed. The performance of the prototype is in line with the expectation by experiments. Its power quality, MPPT efficiency, islanding protection are quite good.