Research On Modular Structure Of Photovoltaic Array And Its Control Technology

Photovoltaic power generation technology is developing rapidly.At present,distributed photovoltaic power generation systems are the most widely used.The photovoltaic arrays that constitute distributed photovoltaic power generation systems are usually composed of anti-parallel diodes of photovoltaic cells.When the shadow is blocked,the operating characteristics of photovoltaic cells usually have multiple peaks.This will result in a complex maximum power point tracking(MPPT)control strategy with power capture losses.Aiming at the current research status,this thesis designs a photovoltaic array based on modular structure,which realizes the optimized management of photovoltaic array energy while simplifying the MPPT control strategy.This topic designs the main topology of the modular structure photovoltaic power supply and the control strategy of the corresponding unit.In the main topology,the photovoltaic battery is used as the sole energy source to cooperate with the energy storage device to supply power to the load,and the DC/DC circuit is used to complete the voltage level of each unit.Implementation of transformation and control strategies.The energy balance-based MPPT control strategy and the improved disturbance observation control strategy of the photovoltaic cell unit are compared and analyzed.At the same time,the energy output control strategy and the double closed-loop control strategy of the output unit are compared and analyzed,and the photovoltaic cell is more favorable.Energy capture and control strategies to increase load energy utilization.The photovoltaic arrays based on traditional structure and modular structure are compared and analyzed.The control strategies of photovoltaic arrays under normal illumination and shadow occlusion are designed respectively.The photovoltaic arrays composed of modular photovoltaic power cascades are loaded.The distribution control realizes the flexible allocation of the energy required for photovoltaic power generation and load between modules,which is equivalent to increasing the surplus power available to the system,prolonging the service life of the energy storage device and realizing the optimal management of the energy of the photovoltaic array.In order to verify the feasibility of the proposed design,the simulation model of modular structure photovoltaic power supply was built by MATLAB/Simulink.Based on the feasibility of simulation and verification of energy control strategy,the energy flow under the overall control strategy of the system was simulated.The simulation then verified that the energy harvesting capability of the photovoltaic array based on the modular structure under the same environmental conditions is greater than that of the photovoltaic array based on the conventional structure.Finally,based on the design scheme,the hardware circuit and software control of the single-module experimental prototype were completed.Two 20 W experimental devices based on DSP-TMS320F28335 were built.Based on the feasibility of the experimental single-module control strategy,the modular structure was verified.Feasibility of the load distribution control strategy for photovoltaic arrays.