Compound control method of photovoltaic grid-connected inverter

Abstract

The invention discloses a compound control method of a photovoltaic grid-connected inverter, relating to a photovoltaic grid-connected inverter. The control method of the traditional inverter has the defects of larger harmonic distortion of the output current of the inverter and poor wave form quality. The compound control method is characterized by comprising the steps of: detecting a DC busbar voltage and a three-phase current outputted by an inverter, calculating a d shaft current reference value according to the DC busbar voltage; converting the three-phase current output by the inverter into a d shaft current measured value and a q shaft current measured value; obtaining a current difference; respectively calculating according to the current difference to obtain a PI control voltage compensating value, a resonance control voltage compensating value and a repeating control voltage compensating value by a PI control module, a resonance control module and a repeating control module; and generating a PWM (Pulse Width Modulation) wave by the PWM control module according to a composition result of the PI control voltage compensating value, a resonance control voltage compensating value and a repeating control voltage compensating value. According to the invention, specific subharmonics and periodic disturbance are inhibited, stability of the inverter is ensured, and dynamic property of the inverter is improved.

Description

technical field [0001] The invention relates to a photovoltaic grid-connected inverter. Background technique [0002] With the development of society and the advancement of technology, energy issues have become increasingly prominent. Extensive use of non-renewable energy such as coal and oil will not only fail to meet the goals of sustainable development, but will also cause huge pollution to the environment. Renewable energy represented by solar energy, wind energy, and tidal energy has become an important direction for the development of new energy in the future. Among them, solar photovoltaic power generation has been highly valued by energy experts from various countries due to its environmental protection, high efficiency, and ease of large-scale utilization. [0003] As an important part of industrialization development, photovoltaic grid-connected power generation system has developed rapidly. As the interface between the power generation system and the mains netw...

AI Technical Summary

Problems solved by technology

However, although the traditional inverter control method based on voltage and current double-closed-loop PI control can meet the control performance requirements of the system to a certain extent, due to the influence of grid disturbance and non-ideal factors of switching devices, the total output current of the inverter High harmonic distortion (THD) and poor waveform quality

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