Nonlinear differential smoothing feedforward control method for distributed optical storage grid-connected system

Abstract

The invention relates to a nonlinear differential smoothing feedforward control method for a distributed optical storage grid-connected system. The nonlinear differential smoothing feedforward controlmethod comprises the steps of: an energy storage unit control step, which is implemented by passing an input power instruction of a bidirectional DC-DC converter in an energy storage unit through a first nonlinear differential smoothing feedforward controller and a first differential smoothing feedback controller separately, and acquiring a duty ratio of the bidirectional DC-DC converter in the energy storage unit according to output results; and a three-phase DC-AC grid-connected converter control step, which is implemented by outputting a reference of a DC-AC grid-connected converter in a three-phase DC-AC grid-connected converter smoothly and passing the reference through a second nonlinear differential smoothing feedforward controller and a second differential smoothing feedback controller separately, and acquiring a grid-connected voltage of the DC-AC grid-connected converter in the three-phase DC-AC grid-connected converter according to output results. Compared with the prior art, the nonlinear differential smoothing feedforward control method has the advantages of excellent control performance, wide stability domain, good robustness and the like.

Description

technical field [0001] The invention relates to the control field of a distributed optical-storage grid-connected system, in particular to a nonlinear differential smoothing feed-forward control method for a distributed optical-storage grid-connected system. Background technique [0002] Distributed photovoltaic power generation has intermittent, random, and non-linear characteristics. Using energy storage battery technology to smooth fluctuations in photovoltaic output power is one of the effective means to achieve high-penetration distributed photovoltaic grid-connected stable operation. However, in practical applications, the energy storage battery is restricted by the reaction of chemical materials, which affects its response speed, and it is difficult to meet the dynamic performance requirements when the photovoltaic output fluctuates frequently. Therefore, it is urgent to design a simple and practical solar-storage coordinated control strategy to further improve the ene...

AI Technical Summary

Problems solved by technology

The existing nonlinear differential smoothing control method adopts feed-forward control, combined with PI feedback control to design a controller, which can effectively expand the stability domain of the system, but the PI feedback controller cannot achieve fast response and small overshoot. It is difficult to meet the requirements of grid-connected dynamic performance and high power quality in the application

The existing nonlinear differential smoothing control method also designs a controller from the perspective of feedback control to achieve system stability control, but there is a problem that the response speed of the energy storage battery cannot meet the dynamic performance requirements of grid connection when the photovoltaic output fluctuates rapidly.

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