Photovoltaic cell maximum power point tracking method

Abstract

The invention provides a photovoltaic cell maximum power point tracking method, which combines an open-circuit voltage proportionality coefficient method and an improved variable-step conductance increment method on the basis of basic principles of the open-circuit voltage proportionality coefficient method and the variable-step conductance increment method, so as to realize tracking of a photovoltaic cell maximum power point. The photovoltaic cell maximum power point tracking method comprises the following steps of: setting a dynamic voltage value Vset through data analysis; when the voltageof a photovoltaic cell operating point is smaller than the set dynamic voltage value Vset, changing a duty ratio by adopting the open-circuit voltage proportionality coefficient method; and when the voltage of the photovoltaic cell operating point is greater than the set dynamic voltage value Vset, tracking the maximum power point MPP by adopting the improved variable step conductance increment method. According to the photovoltaic cell maximum power point tracking method, the open-circuit voltage proportionality coefficient method is combined with the improved variable-step conductance increment method, so that the tracking speed of the maximum power point can be increased, meanwhile, the problem of misjudgment of a traditional variable-step conductance increment method under the condition of abrupt change of irradiance can be solved, and the stability and efficiency of the system are improved.

Description

technical field [0001] The present invention relates to the technical field of new energy application, in particular to a method for tracking the maximum power point of a photovoltaic cell. Background technique [0002] At present, the commonly used maximum power tracking methods include hill climbing method, disturbance observation method, conductance incremental method, fuzzy control method, etc. Among them, the conductance incremental method has higher tracking accuracy and has good tracking performance in the case of rapid environmental changes. , so it is widely used. The incremental conductance method is to complete the tracking of the maximum power point by comparing the instantaneous reactance and reactance variation in the photovoltaic cell array. [0003] Since the output power of the photovoltaic power generation system is greatly affected by temperature and irradiance, it is difficult for the traditional incremental conductance method to ensure the tracking spee...

AI Technical Summary

Problems solved by technology

[0003] Since the output power of the photovoltaic power generation system is greatly affected by temperature and irradiance, it is difficult for the traditional incremental conductance method to ensure the tracking speed and reduce the oscillation near the maximum power point (MPP). If the step size is large, the system will track the MPP very fast, but the oscillation near the MPP will be large, causing unnecessary power loss; if the step size is set relatively small, the system will have a small oscillation near the MPP but the tracking speed will be slower, also causing power loss

In addition, when using the conductance incremental method with variable step size, misjudgment may occur regardless of whether the irradiance is changed or not, causing the working point to move away from the maximum power point, resulting in waste of resources, and even system crashes in severe cases.

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