Study Of PV Power Generation Technology Based On Quasi-Z-Source Inverter

Photovoltaic power generation has the advantages of sustainable, no noise pollution, convenient installation, etc. It is developing rapidly in the field of new energy. Traditional photovoltaic grid-connected inverter has the defects of small input voltage range, low efficiency and poor reliability. Quasi-Z-source inverter overcomes the deficiencies of the traditional inverter due to the storage characteristics of the inductor and capacitor network,and it is more suitable for the use of photovoltaic power generation occasion. In this paper, the single-phase quasi-Z-source inverter and its application technology in photovoltaic grid-connected power generation as the study focus, mainly carried out the following work:The modulation strategy of quasi-Z-source inverter is mainly studied on the basis of analyzing the working principle and the voltage boost characteristic of the quasi-Z-source inverter. Study thoroughly of modulation algorithm of quasi-Z-source inverter. Research on space vector modulation algorithm in single-phase quasi-Z-source inverter application by simulation experiments, and improved the space vector modulation algorithm. Through contrast improved space vector modulation algorithm and the traditional SPWM modulation algorithm, the unified relationship of two single phase modulation algorithms is established. Summed up the advantages and disadvantages of different modulation algorithms in single-phase quasi-Z-source inverter.Study the closed loop control strategy based on mathematical model, and completed closed loop design of voltage loop and current loop. A new maximum power tracking algorithm is proposed in the maximum power tracking loop control. Studied the effects of system parameters on the dynamic characteristics. The closed-loop control of the maximum power tracking loop, the capacitor voltage loop and the grid connected current loop is designed based on the system model. Maximum power tracking algorithm integrated the advantage of disturbance observation method and incremental conductance method and completed the system maximum power point tracking control. Voltage loop and current loop were designed and achieved the desired control effect.Determine the parameters and selection of the main component of the system. Designed the main hardware circuit of the system, Studied and designed through state insertion method totally implemented by DSP software programming and reduced the design of peripheral circuit.The model is built in the MATLAB/simulink environment, and the experimental platform is designed on the basis of the simulation research. The simulation and the experimental results meet the theoretical requirements.