Voltage converter for power optimization and mode switching method thereof

Abstract

The invention relates to a voltage converter for power optimization and a mode switching method thereof. The voltage converter is used for absorbing electric energy from a corresponding photovoltaic module and is connected in series, output voltages of the voltage converters are superposed to obtain a DC bus voltage, an expected voltage output from the voltage converter is equal to a ratio, whichis calculated by an external power provided by the corresponding photovoltaic module on the total power, multiplied by a set value of the DC bus voltage, the voltage converter enters a first mode of voltage drop when the ratio of the expected voltage sum of the voltage converters and maximum power point voltage of the corresponding photovoltaic module does not first gain, the voltage converter enters a second mode of voltage rising when the ratio of the expected voltage sum output from the voltage converter and the maximum power point voltage of the corresponding photovoltaic module is not lower than a second gain, and the voltage converter enters a third mode which an output voltage is equal to an input voltage when the ratio of the expected voltage sum output from the voltage converter and the maximum power point voltage of the corresponding photovoltaic module is between the first gain and the second gain.

Description

technical field [0001] The present invention mainly relates to the field of solar power generation, more precisely, it relates to a switching scheme for DC power supply adaptively adopting step-up or step-down in a power generation system containing photovoltaic modules to ensure the smoothness of the DC bus voltage changes to avoid excessive oscillations and minimize power losses in the voltage converter. Background technique [0002] In the large-scale centralized and battery string lumped optimization scheme, the goal is to complete the maximum power point tracking at the level of the battery string composed of components connected in series. The disadvantage is that if some batteries in the battery string are aging or damaged Or when it is in the state of being shaded, it will seriously affect the overall power generation efficiency of a battery string. The industry's countermeasures, the main solution is to equip each component with an independent power optimizer and...

AI Technical Summary

Problems solved by technology

Considering the above disadvantages of photovoltaic power plants, especially the mismatch of photovoltaic modules, the mismatch is mainly caused by the combination of battery voltage and current, the battery is blocked by buildings or the surface of the battery absorbs dust, cloud cover, different degrees of aging and temperature and Drastic changes in radiation intensity, etc., are all inducements of mismatch, which directly lead to unbalanced power loss of photovoltaic modules

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