Reduction method of lcl-t module of photovoltaic power generation system

Abstract

A method for reducing the order of the LCL-T module of a photovoltaic power generation system. Under the condition that the isolation transformer is not saturated, a mathematical model based on the LCL-T module of the photovoltaic power generation system is established, and the filter input voltage and the filter output current and the transformer primary voltage are obtained respectively. The transfer function between the side currents, the weighted feedback current is introduced to achieve zero and pole cancellation, and the purpose of simplification is achieved; in the case of isolation transformer saturation, considering the primary and secondary side resistances and excitation resistance of the isolation transformer, the input voltage of the filter is obtained. The transfer function to the output current of the primary side of the transformer adopts the Rolls approximation method of the high-order system of the Rolles stability law, and reduces the high-order LCL-T module to a first-order system of equivalent resistance and equivalent inductance in series; PSCAD / EMTDC modeling simulation and MATLAB data processing, Bode plot verification, and comparing the detailed model with the equivalent model results can effectively shorten the simulation time and improve the simulation accuracy.

Description

technical field [0001] The invention relates to the technical field of photovoltaic grid connection, and is a method for reducing the order of an LCL-T module of a photovoltaic power generation system. Background technique [0002] With the increase of the penetration rate of photovoltaic power generation systems, the network system structure becomes more and more complex. The higher model order of photovoltaic power generation systems leads to a large amount of calculation, which brings problems such as model validity, data correction, large memory usage and long simulation time. And other issues. Therefore, an equivalent model needs to be studied to solve the problem of large memory footprint and long simulation time. The LCL-T module is a module composed of an LCL filter and an isolation transformer T. For the reduction process of the LCL-T module of the photovoltaic power generation system, it is necessary to consider the saturation and non-saturation of the transformer...

AI Technical Summary

Problems solved by technology

[0002] As the penetration rate of photovoltaic power generation systems increases, the network system structure becomes more and more complex. The higher model order of photovoltaic power generation systems leads to a larger amount of calculation, which brings problems such as model validity, data correction, large memory usage and long simulation time. And other issues

Therefore, it is necessary to study an equivalent model to solve the problem of large memory usage and long simulation time

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