Research On Optimal Structure And Control Strategy Of The Photovoltaic Pump System

Since the energy crisis in the 1970 s,the development of new energy is increasingly brought to the concern by the countries around the world,and the photovoltaic(PV)power generation technology as one of the best renewable energy power generation technology has become more attention.The PV pump device as an important application of the PV power generation,has experienced decades of development.In developing countries,the water is still difficult problem,especially the grid is not covered in the remote areas,which seriously obstructs the improvement of people's living standards and the society development.A PV pump system is studied in this paper.The three-phase AC asynchronous motor is taken as the research object,the mathematical model of PV array,maximum power point tracking method,variable frequency control method of motor speed,PWM modulation strategy,optimal operation and software and hardware design are studied,the following contents are mainly included:(1)The mathematical model of PV array is established,a simulation model for the PV array in the Matlab/Simulink is built,and output characteristics of the PV array are analyzed under the different condition of illuminations and temperatures.(2)The typical maximum power point tracking(MPPT)algorithm is analyzed,a novel MPPT algorithm without any DC current sensor is studied,and its working principle is discussed in detail.(3)VVVF control mode and the optimization scheme of V/F curve are discussed for the PV pump system,PWM modulation method based on injecting the third harmonic is studied,and the optimal operation scheme of the PV pump system is also analyzed.(4)The hardware circuit and the software program of the system are designed,the experimental platform is built and experimental verification is carried out.The simulations and experiments prove the correctness and rationality of system analysis and design.