Maximum power point tracking method of self-adaption variable step sizes with saturation constraint

Abstract

The invention discloses a maximum power point tracking method of self-adaption variable step sizes with saturation constraint. The method comprises steps of 1) establishing a photovoltaic cell model; 2) establishing a boost circuit model; 3) searching the maximum power point; and converting D into a PWM signal by use of pulse width modulation based on sawtooth wave carrier waves and allowing the PWM signal to pass through a triode in a PWM single control boost circuit. The PWM signal based on the sawtooth wave carrier waves is used for directly controlling duty ratio of the boost circuit to track the maximum power point in high efficiency; when the system environment changes suddenly, the control algorithm can reliably work so that the maximum power of the photovoltaic system can be rapidly tracked; according to the self-adaption variable step sizes of positions where the power point locates, the system is allowed to use the bigger step size to perform rapid tracking when being away from the MPP, so duty ratio near the MPP is reduced and vibration is avoided; and by adding the saturation constraint, invalid tracking caused by too big step size when the gradient value may be too big can be avoided.

Description

technical field [0001] The invention relates to a maximum power point tracking method with an adaptive variable step size with saturation limitation, and belongs to the technical field of control systems. Background technique [0002] Solar energy is a clean energy that can be recycled. Photovoltaic cells are currently the main way to directly utilize solar energy. Their power generation mode is fundamentally different from the traditional power generation mode. Photovoltaic power generation is intermittent and unstable, and the output power of photovoltaic cells is affected by light intensity and ambient temperature. Therefore, under changing working conditions, using effective algorithms to quickly track the maximum power point of photovoltaic cells can effectively improve the power generation efficiency of photovoltaic modules. [0003] Maximum power point tracking MaximunPowerPointTracking (MPPT) control mainly includes constant voltage tracking (CVT), disturbance and o...

AI Technical Summary

Problems solved by technology

The intelligent algorithm is effective for the nonlinear processing of the P-U curve, and a large number of calculations and processing are required for the data, so the low-cost processor cannot meet the requirements; the constant voltage tracking method is not the real maximum power point tracking in essence, this tracking The influence of the environment on the output voltage of the array is ignored, so it is only a kind of voltage stabilization control; the perturbation and observation method will produce oscillation near the maximum power point; and there are difficulties in the selection of the step size and threshold of the conductance incremental method

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