A control method of photovoltaic grid-connected inverter based on lcl filter

Abstract

The invention discloses a control method for a photovoltaic grid-connected inverter based on an LCL filter. The inverter is controlled, and signals of an output current reference value of the inverter are extracted from the output current reference value, wherein the signals of the output current reference value comprise the output current tracking value and the differential signal; then the tracking value and the differential signal of the output current actual value are extracted from the output end of the inverter, and all disturbance contained in the inverter is estimated; the difference between the output current reference value and the output current actual value of the inverter is controlled; all the disturbance contained in the inverter are compensated through all the obtained disturbance estimation values, and the actual controlled quantity of the inverter is obtained. The control method for the photovoltaic grid-connected inverter based on the LCL filter lowers the THD and the DCI of output currents, improves the quality of grid-connected electricity, enhances the running reliability of the system, avoids halt faults caused by environment factors, improves the robustness of the system and resists the adverse effect on the system from the internal disturbance and the external disturbance.

Description

technical field [0001] The invention relates to an inverter control method, in particular to a control method for a photovoltaic grid-connected inverter based on an LCL filter. Background technique [0002] New energy has played an important role in alleviating energy shortages and environmental crises, ensuring sustainable social development, and maintaining national energy security. Photovoltaic grid-connected power generation technology has become an efficient use of new energy due to its advantages of adjusting peak and valley loads and realizing effective use of resources. key technologies. At present, in actual engineering, the normal operation of the photovoltaic grid-connected power generation system is affected by factors such as light intensity, ambient temperature, air humidity, altitude and device aging, resulting in low operating efficiency of the photovoltaic grid-connected power generation system and frequent shutdowns, etc. Fault. As a result, the service l...

AI Technical Summary

Problems solved by technology

According to the mathematical model of the inverter obtained in the previous section, due to the influence of the sum disturbance and the nonlinear characteristics of the components of the LCL filter, w(·) in the mathematical model is a complex nonlinear time-varying function, so the traditional Control methods (such as PI control, repetitive control, proportional resonance control, etc.) have been unable to achieve accurate and reliable control of the actual system, which is also the main reason why the control effect of traditional control methods is not ideal in actual projects, and it is difficult to achieve fast and stable tracking of output current

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