Adaptive three-phase LCL grid-connected inverter control method

Abstract

The invention discloses an adaptive three-phase LCL grid-connected inverter control method. The adaptive three-phase LCL grid-connected inverter control method further comprises the following steps that a novel capacitor voltage feedback active damping control strategy is constructed, and a first-order high-pass filter link is adopted to replace a capacitor voltage differential feedback link; thepower grid internal resistance variation is detected; and according to the detected variable quantity of internal resistance of a power grid, the cut-off angular frequency, a PI parameter and a grid-connected current feedback coefficient of the high-pass filter link are corrected in real time. The novel capacitor voltage feedback active damping control strategy is constructed, and the first-orderhigh-pass filter link is adopted to replace the capacitor voltage differential feedback link, so that the problem that a system is difficult to achieve due to the fact that the differential link can amplify a high-frequency signal is solved; and related control strategy parameters are corrected in real time to ensure that system control strategy parameters do not fail when the internal resistanceof the power grid changes, and the grid-connected electric energy quality of the system can be effectively improved.

Description

technical field [0001] The invention relates to the field of power electronics, in particular to an adaptive three-phase LCL grid-connected inverter control method. Background technique [0002] With the rapid development of micro-energy generation technology represented by renewable energy, distributed power generation technology and energy storage technology, new energy grid-connected power generation is gradually becoming a research hotspot. With the widespread distribution of distributed power, the power grid is becoming more and more The characteristics of the weak grid. In the grid-connected system of new energy power generation, the interface device between the distributed power supply and the grid is the LCL grid-connected inverter. The LCL grid-connected inverter plays the role of converting DC and AC power forms, and delivers AC power to the grid that meets the grid requirements. play an important role in the process. [0003] In the three-phase LCL inverter grid...

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Problems solved by technology

[0005] The present invention aims at that in the prior art, when the power grid presents the characteristics of a weak power grid, the change of the internal resistance of the power grid will cause the change of the resonance frequency of the system, which makes the control parameters invalid, and finally leads to the instability of the system, and at the same time reduces the grid-connected electric energy output by the system Quality and other issues, creatively proposed an adaptive three-phase LCL grid-connected inverter control method, through real-time correction of relevant control strategy parameters, to ensure that the system control strategy parameters do not fail, and can effectively improve the grid-connected power quality of the system

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