Research On Control Strategy Of Photovoltaic MPPT Based On Conductance Incremental Method

In order to make the supply of resources meet the rapidly developing world situation,it has a strong practical significance for the development and application of renewable resources.Photovoltaic generation has unique advantages such as rich reserves,easy installation of related equipment,and low maintenance costs,and has been recognized and applied in many countries around the world.However,due to its unstable conversion efficiency and non-linearity of battery characteristics,which restricts the development and application of photovoltaic generation technology,the maximum power point tracking(MPPT)technology must be used to ensure the output efficiency of the photovoltaic generation system and system stability.This paper studies the maximum power point tracking technology of the photovoltaic generation system.Firstly,a mathematical model of photovoltaic cells and their arrays is built,the realization mechanism of photovoltaic generation system MPPT is analyzed and the output characteristics of photovoltaic cells are analyzed.Then it classifies commonly used MPPT algorithms,analyzes in detail the problems existing in the MPPT technology commonly used under the changing external environmental conditions during the maximum power point tracking process,and proposed a new variable step size algorithm and improved conductance increment method are also proposed.The new variable step size algorithum uses the disturbance step size adjustment coefficient proposed in this paper,which greatly improves the tracking accuracy and response speed of the system.The improved conductance increment method introduces the instantaneous changes of power and voltage for detection and judgment,and introduces allowable errors and flag values.When the external irradiance changes,there is no need to set the speed factor in advance to ensure the convergence of the algorithm,which greatly simplifies the photovoltaic power generation system.In the dynamic response stage,the power change information is introduced to avoid the misjudgment phenomenon caused by the traditional algorithm when the irradiance changes,and improve the tracking accuracy of the algorithm.When the system reaches the steady-state phase,the flag value and the limiting conditions are introduced,which effectively prevents the steady-state oscillation and reduces unnecessary power loss.