MPPT Controller Design Of Photovoltaic Power Generation Based On DSP

In recent years,the photovoltaic industry as an emerging sunrise industry is booming.Along with the expansion of photovoltaic power generation,related technology research and development work has been progressed.Overall development direction is shifting from focusing on the quantity of power generation to the quality of power and the efficiency of power.Due to the output of photovoltaic cells have strong nonlinear characteristics.The output power of photovoltaic cells is not only related to the load characteristic,the external environment such as light intensity,temperature can also affect it.This makes the energy conversion efficiency of photovoltaic system reduce greatly.To solve above problems,this paper designs a MPPT controller based on DSP around the maximum power point tracking(MPPT)technology and improve the utilization efficiency of solar energy through tracking the maximum output power of the photovoltaic cells.With MATLAB/Simulink software,on the basis of mathematical model this paper sets up the photovoltaic cell model first,which is suitable to actual project application better,and this paper analyzes the regularity of photovoltaic properties changing with the external environment.Then the paper analyzes the realization mechanism of MPPT,after weighing the advantages and disadvantages of kinds of DC/DC circuits,choosing Boost circuit as the main circuit of MPPT control system.After analyzing the present several popular MPPT algorithms,fuzzy control is applied to the MPPT control and this paper puts forward a variable step size incremental conductance algorithm that using fuzzy control to calculate step size.The algorithm has the property of adjusting the step length automatically according to the change of light intensity and temperature.The step size is increased greatly when the operating point is far from the MPP,with the working point near the maximum power point,matching the appropriate step until the trace is completed.Then,this paper makes the simulation with fuzzy logic toolbox.The results show that the algorithm can effectively overcome the contradiction between the dynamic response speed and the steady-state tracking accuracy caused by the selection of step size and can achieve good dynamic and steady state performance.This paper designs the general structure and control scheme of the system,choosing TMS320F28035 controller as the core control chip in the MPPT control system.This paper completes the design of the hardware circuit system including power circuit,sampling circuit,drive circuit and protection circuit,writing the program containing the main program,AD sampling program,maximum power point tracking program and PWM generation program using CCS development environment.Finally,this paper debugs the hardware and software of welding circuit and monitoring of the results by the PC program of data collecting and searching system in LabVIEW.The result shows that the design of MPPT controller can mainly achieve the expectations.