MPPT (maximum power point tracking) control device and method of photovoltaic inverter based on perturbation method

Abstract

The invention discloses a MPPT (maximum power point tracking) control device and method of a photovoltaic inverter based on perturbation method. The device comprises a DC (direct current) voltage-current detection circuit, a drive circuit, an AC (alternating current) current sampling circuit, a grid voltage sampling circuit and a DSP (digital signal processor). The method is an improvement based on the normal perturbation method, and comprises calculating a proper step length by using PID (proportion integration differentiation) control, wherein the calculated step length has a larger value when the currently tracked point is away from the maximum power point, or has a smaller value when the currently tracked point is near the maximum power point. By improving the perturbation method, the method provided by the invention can overcome the disadvantages of the existing perturbation method, and can improve the MPP (maximum power point) tracking efficiency.

Description

technical field [0001] The invention relates to an MPPT control device and method for a solar photovoltaic power generation system, in particular to a photovoltaic inverter MPPT control device and method based on a disturbance method, belonging to the technical field of maximum power point tracking of photovoltaic inverters. Background technique [0002] Solar photovoltaic power generation technology is a technology that converts inexhaustible solar energy into electricity, and is gradually being accepted and widely used by people. However, it is still difficult to widely apply photovoltaic power generation technology. The most important reason is that the conversion efficiency of solar cells is relatively low, resulting in high cost of photovoltaic power generation. The MPPT control algorithm is to use solar cells more completely and improve battery utilization efficiency. The commonly used MPPT algorithm is the perturbation method. Although the perturbation method is very...

AI Technical Summary

Problems solved by technology

The commonly used MPPT algorithm is the perturbation method. Although the perturbation method is very convenient to use, it also has two disadvantages: one is that the photovoltaic inverter will oscillate around the MPP point, which will cause energy loss and reduce the efficiency of solar cells; It is difficult to determine the disturbance step size of the ordinary disturbance method. If the step size is too large, the degree of oscillation will be increased. If the step size is too small, it will increase the time to find the MPP point.

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