Photovoltaic three-phase grid control method for fast and steadily implementing maximal power tracing

Abstract

The present invention relates to a photovoltaic three phase synchronization control method realizing maximum power tracking swiftly and stably, which belongs to the technical field photovoltaic power generating control. The method includes the steps as follows: judging the DeltaP / DeltaV value according to the power difference DeltaP between the current time k and the previous time and the voltage difference DeltaV; working out the Iref(k) when the photovoltaic array produces the maximum power; using the Iref(k) to adjust the uq* under the coordinates in vectorial synchronous rotation with the electric network voltage; acquiring six ways of space vectorial SVPWM impulse series according to the rotation angle degree Theta of the three phase electric network voltage, with the aim to control the inverter in order to ensure that the output current of the photovoltaic inverter has the same phase position as that of the mains voltage while ensuring the photovoltaic array is realizing the maximum power output tracking. The power factor is 1. The present invention also can adjust the Idref(k) according to local load requirements, therefore achieving adjustment to the power factor, with low synchronization current harmonic wave distortion factor.

Description

technical field [0001] The invention relates to a photovoltaic three-phase grid-connected control method for quickly and stably realizing maximum power tracking of a photovoltaic array, and belongs to the application field of photovoltaic power generation system control technology. Background technique [0002] The development and utilization of abundant and vast solar energy without and less pollution to the environment is not only an urgently needed supplementary energy in the near future, but also the basis of the future energy structure. Therefore, it is studied how to realize the organic combination of the maximum power point tracking (MPPT) algorithm and the photovoltaic grid-connected control technology, so that the photovoltaic grid-connected power generation system can quickly track the maximum value of the photovoltaic array under the environment of different illumination and temperature changes. It is of great significance to ensure that the power operating point ...

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Problems solved by technology

figure 1 clearly shows a 300W p A set of output voltage and power relationship curves of photovoltaic arrays that vary with light intensity. At the same time, the figure shows the maximum power tracking process, while the existing maximum power point tracking methods such as constant pressure method, first-order hill climbing method, and conductance modulation method It is difficult to quickly and smoothly track the maximum power operating point (MPP) of the photovoltaic cell array, and these methods are mostly used in independent photovoltaic power generation systems, such as battery charging control systems. Although the normal pressure method can be applied to photovoltaic grid-connected The control system can meet the stability requirements of photovoltaic grid-connected systems, but it is difficult to implement maximum power tracking under different light intensities, which will cause additional power loss

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