Non-active disturbance maximum power tracking method in photovoltaic grid-connected inverting system

Abstract

The invention relates to a non-active disturbance maximum power tracking technology in a photovoltaic grid-connected inverting system, which achieves rapid and disturbance -free photovoltaic array maximum power tracking control according to natural fluctuation of the output power of a photovoltaic array. A working voltage of the photovoltaic array is sampled in a carrier cycle, and the current output power is calculated; a corresponding bus voltage value of the maximum power is searched in a voltage pulsation cycle, the voltage value is taken as a voltage instruction of the next cycle, and the working voltage of the photovoltaic array moves towards a maximum power point; a peak point of the array power variation is positioned in the midpoint of voltage pulse when the working voltage of the system moves to the maximum power point, and the bus working voltage is stabilized according to a maximum power tracking control strategy. The method can not generate the disturbance influence on a grid, has rapider maximum power tracking speed, and is unnecessary to select and set any parameter and suitable for the maximum power tracking control of the single-phase or three-phase photovoltaic grid-connected inverting system.

Description

technical field [0001] The invention relates to the field of photovoltaic power generation, in particular to a non-active disturbance maximum power tracking method in a photovoltaic grid-connected inverter system. Background technique [0002] The output power of a photovoltaic array is strongly nonlinear and is closely related to meteorological conditions such as sunlight intensity and ambient temperature. Under a certain ambient temperature and different sunlight intensities, the current-voltage (I-V) and power-voltage (P-V) characteristic curves of photovoltaic arrays are as follows: figure 1 (a) and figure 1 (b) shown. Depend on figure 1 (b) It can be seen that under a certain sunlight intensity and ambient temperature, the output power of the photovoltaic array can reach the maximum value only when the photovoltaic array operates at a certain voltage, and the operating point of the photovoltaic array at this time reaches the peak of the output P-V curve The highest ...

AI Technical Summary

Problems solved by technology

This active disturbance method involves the selection of disturbance step size, disturbance frequency and speed, etc. There is also a variable step size method to speed up the tracking speed. If the relevant parameters are not well selected, it will affect the tracking efficiency of the system and affect the grid-connected current and power. Generate disturbances that affect the quality of grid-connected current

In addition, this active disturbance method needs to be disturbed all the time during the operation of the system, even if the operating voltage has reached the maximum power point

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