Photovoltaic module output characteristic judgment method

Abstract

The invention discloses a photovoltaic module output characteristic judgment method which is mainly characterized in that a single battery serves as a basic unit, output characteristics of a blocked battery and a battery string with the blocked battery are firstly analyzed according to current flowing through a photovoltaic module, and the conducting state of a bypass diode is further judged based on theoretical analysis for volt-ampere characteristics of the bypass diode, so that multimodal characteristics of the photovoltaic module blocked by shadow are calculated. By the method, the conducting point of the bypass diode can be accurately judged, so that peak points of an I-V curve of the module are accurately reflected, and a foundation is laid for simple and accurate simulation of the performance of the module under the condition of mismatch.

Description

technical field [0001] The invention relates to a method for judging the output characteristics of a photovoltaic module, belonging to the technical field of solar photovoltaics. Background technique [0002] The output characteristics of solar cells are complex and have nonlinear characteristics, which are mainly affected by irradiance, temperature and load conditions. Since the output current and voltage of a single cell are small, in practical applications, the single cells are connected in series to form a photovoltaic module, and the photovoltaic modules are connected in series and parallel to form a photovoltaic array to achieve the required current and voltage values. In the actual system operation, the mismatch phenomenon caused by shadow occlusion will cause the reverse bias of the photovoltaic cells to consume power as a load, which not only reduces the overall output power of the photovoltaic array, but also may cause hot spot effects, causing irreversible damage ...

AI Technical Summary

Problems solved by technology

Among them, Zhai Zaiteng et al. proposed a method based on the current flowing through the components using a piecewise function to describe the output characteristics of the partially shaded photovoltaic array. It is based on the component as the basic unit, and each component is connected in parallel with a protective function bypass diode, which can be more accurate. The output performance of the series array is simulated when some components are blocked, but because the actual blocking situation is more complicated, further research is needed; Xu Qingshan et al. studied the components containing multiple bypass diodes, and divided the current flowing through the components into There are two paths, that is, the current flowing through the battery string and the bypass diode, and the Newton-Raphson method is used for iterative solution, while Y.-J.WANG takes the bypass diode protection string as the basic unit, according to the component string The voltage is calculated and solved by the method of piecewise function. Both of these two methods can accurately obtain the output characteristics of the array in the actual complex situation, but the former has a large amount of calculation, while the latter uses the method of implicit function, which has a negative impact on the overall calculation. a little inconvenience

Images