Method of combining maximum power tracking and u‑f curve self-optimization of photovoltaic water pump system

Abstract

The invention discloses a method of maximum power tracking and U-f curve self-optimization for a photovoltaic water pump system. At relatively low frequency, output frequency f of a frequency converter is used to control output power Pm, at relatively high frequency, output voltage amplitude U of the frequency converter is used to control the output power Pm, and a power change corresponding to unit amplitude is relatively small, so that the output power of the frequency converter can be controlled finely till a water pump tracks maximum power output by a photovoltaic panel. By adoption of the method of combining the maximum power tracking and the U-f curve self-optimization for the photovoltaic water pump system, operation of a motor with optimal efficiency can be realized without acquisition of an optimal U-f curve of the motor in advance, and poles of a photovoltaic output voltage-power curve can be tracked, thereby improving overall operational efficiency of the photovoltaic water pump system.

Description

Technical field [0001] The invention belongs to the technical field of control of a photovoltaic water pump system, and specifically relates to a method for combining the maximum power tracking of a photovoltaic water pump system and the self-optimization of a U-f curve. Background technique [0002] Water is an indispensable resource for human survival. Humans need a lot of water for daily drinking and irrigation. However, the fresh water resources we need are stored underground, the so-called groundwater, and a small amount of ground water, that is, the water in rivers and lakes. However, due to the development of human society, a large number of cities and populations are far away from rivers and lakes, and some remote mountainous areas have no grid connection and lack of surface water. These occasions need to pump water to meet the needs of drinking water and irrigation, so they need to use The motor water pump pumps water. [0003] The traditional water pumping method is usua...

AI Technical Summary

Problems solved by technology

At present, in the AC photovoltaic water pump system, the commonly used maximum power tracking method is based on the adjustment of the output frequency of the inverter to adjust the output power for maximum power tracking. The output power corresponding to the frequency of the unit step changes little, and the tracking control is more accurate, but at a higher frequency, because the output power corresponding to the frequency of the unit step changes greatly, it will bring disadvantages to the control accuracy. influences

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