A double disturbance mppt control method for photovoltaic power generation system

Abstract

The invention discloses a double-disturbance MPPT control method of a photovoltaic power generation system. A switch capacitor converter is employed as a control circuit of MPPT, and is composed of two switch capacitor units SC1 and SC2 and a direct current filter. A double-disturbance P&O algorithm is provided on this basis, the SC1 and the SC2 employ a variable step size algorithm, different speed factors are selected, a bidirectional complementation control mode is formed, namely, only reverse disturbance can be carried out after one enters a dead zone, forward disturbance is completed by the other one. Through the control mode, the disturbance convergence speed is raised, the dead zone problem is solved, starting can be carried out rapidly and stably, misjudgement is reduced, the oscillation phenomenon of a system output power in the maximum power point can be reduced effectively, and energy loss of a photovoltaic module is reduced.

Description

technical field [0001] The invention relates to the field of photovoltaic grid-connected power generation systems. A switched capacitor converter is used to realize MPPT control, so that light energy can be converted into electrical energy output with maximum efficiency. technical background [0002] Today, with the rapid development of distributed power generation systems, modern photovoltaic power grid-connected systems have begun to develop in the direction of low magnetization and miniaturization. Switched capacitor converters have the advantages of small size, light weight, and low magnetization. In photovoltaic power generation systems has great application prospects, then for photovoltaic power generation systems, maximum power point tracking (Maximum PowerPoint Tracking, MPPT) is essential, so how to deal with the situation when the output side of the photovoltaic array is connected to a low-magnetism switched capacitor converter MPPT tracking control of photovoltaic...

AI Technical Summary

Problems solved by technology

[0003] In the photovoltaic MPPT algorithm, the traditional perturbation and observation method can generally be divided into a fixed step size algorithm and a variable step size algorithm. The fixed step size algorithm is difficult to balance speed and accuracy; the variable step size algorithm is difficult to balance the convergence speed and dead zone.

Moreover, the algorithm itself is based on the duty cycle of a single switch output. Once it enters the dead zone, it is difficult to return autonomously, which may cause MPPT tracking failure.

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