Research On Distributed Photovoltaic DC Power Supply And HVDC Power Control

At present, the problem of energy shortage and environmental pollution have become more and more serious, the effective use of renewable energy sources more and more attention. As an effective way to use solar power the technology of photovoltaic(PV)conversion is developing very quicklyThis paper will be solar distributed Photovoltaic DC power supply and the power converter control as the main research object, built a mathematical model for Photovoltaic DC power supply, in the station control flexible DC transmission mode selection, the establishment of steady-state operation model of power converter, analyzed the operation status of the station. These for the analysis of power control strategy, and provided a theoretical basis for the design of control system.First of all, this paper expounds working principle of solar photovoltaic DC power supply, the influence of environmental factors on the DC power supply is analyzed.Established the mathematical model of photovoltaic DC power supply, the conclusion of the relationship between internal resistance and the maximum power point of PV DC power supply of a load is obtained Several common maximum power point tracking algorithm is introduced.Secondly, established a mathematical model of the converter station, the influence of parameters on the flow station operation mode is discussedThen, set up when the grid voltage in three-phase balanced and unbalanced three-phase converter mathematical model of the state, the mathematical models of the software phase locked loop based on the single synchronous rotating coordinate system and the software phase locked loop based on double synchronous rotating coordinate system are established. The principle and control method of phase locking are analyzed.Last part, according to the research on two kinds of phase locked loop and DC power control strategy, Build model of PLL and converter in MATLAB software platform, The use of programmable power supply module for the simulation of the PLL and the converter, Including the three-phase power grid voltage balance and unbalance state, The output waveform results were compared, And the above analysis is verified by simulation platform.