Active damping optimization method for grid-connected current control of L-type grid-connected inverter

Abstract

The invention discloses an active damping optimization method for grid-connected current control of an L-type grid-connected inverter, which solves the problem that the control system is unstable dueto the existence of a digital control delay, and solves the problem of insufficient mid-band phase margin due to a compensation delay. The active damping optimization method includes the following steps: obtaining a difference delta ie of a beat delay output of a current reference preset value iL_ref and an actual current sampled value iL sampled by the system; adding a current prediction method,using the predicted inductor current as a research object, and compensating the delay link. The active damping optimization method is added to a current loop, which essentially adds a second-order differential feedback link into the current loop, the problem that the active high-frequency damping method is added to cause instable mid-frequency band of the system can be solved; a resonance peak caused by a system delay is suppressed; the stability of the system is improved; the gain range of current control is expanded; and dynamic and static errors of the system are reduced.

Description

technical field [0001] The invention belongs to the technical field of grid-connected current control for power quality optimization, and in particular relates to an active damping optimization method for grid-connected current control of an L-shaped grid-connected inverter. Background technique [0002] Due to the increasingly serious problems of environmental pollution and fossil energy crisis, in order to meet energy demand, new energy has been widely developed and utilized. Distributed power generation system has become a research hotspot in recent years. get rapid development. As the core part of distributed power generation, the grid-connected inverter is required to have extremely high output power factor (PF) and extremely low output current total harmonic distortion (THD). Since the grid-connected system has high requirements on power quality, it is necessary to control the output current of the power generation system in order to meet the grid-connected requiremen...

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Problems solved by technology

[0005] The purpose of the present invention is to provide an active damping optimization method for grid-connected current control of an L-type grid-connected inverter, to solve the problem of low and high-frequency harmonics in the current loop of the existing grid-connected inverter, and to increase the control gain There is a contradiction between improving the system stability margin

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