Current control method of LCL type grid-connected inverter single-current feedback

A feedback control and inverter technology, applied in AC network circuits, photovoltaic power generation, electrical components, etc., can solve the problems of no static error tracking and reduction of fundamental frequency components, and achieve low cost, good filtering effect, and high quality small effect

Active Publication Date: 2017-11-24
江苏谷峰电力科技股份有限公司
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Problems solved by technology

[0006] In view of this, this paper proposes a new type of single current feedback control method for LCL grid-connected inverters, which reduces the number of sensors and saves development costs. It solves the deficiency that the traditional single closed-loop feedback cannot track the fundamental frequency component without static error

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  • Current control method of LCL type grid-connected inverter single-current feedback
  • Current control method of LCL type grid-connected inverter single-current feedback
  • Current control method of LCL type grid-connected inverter single-current feedback

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Embodiment Construction

[0048] The invention takes the single-phase photovoltaic grid-connected inverter adopting the LCL filter as the research object, and proposes a novel single current feedback control method to complete the correction of the LCL filter.

[0049] The present invention will be described in detail below in conjunction with the accompanying drawings of the embodiments of the present invention.

[0050] Such as figure 1As shown, a single current feedback control method of an LCL type grid-connected inverter of the present invention comprises the following steps:

[0051] Sampling the grid-side output current i of the grid-connected LCL type grid-connected inverter 2 ; for output current i 2 with given value are compared to get an error signal, which is then fed into the current regulator G i (s), get the first output signal, where the current regulator G i (s) Select a PI regulator; the incoming current passes through the inner loop feedback control link G sd (s) The second ou...

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Abstract

The invention discloses a current control method of LCL type grid-connected inverter single-current feedback, and belongs to the field of grid-connected inverter network access current control. According to the method, a network access current is fed back by a proportion, integral and differential, system damping is increased, and resonance peak inhibition of a grid-connected inverter system of an LCL filter is achieved. By controlling the feedback of the network access current, a transfer function of an LCL type filter grid-connected inverter is designed into a four-order system composed of a fundamental resonance controller and a two-order filter link, compared with a traditional three-order system, a more optimal tracking response of a first-harmonic frequency component can be achieved, system total harmonic distortion is reduced, and the system has excellent dynamic and static performance; meanwhile, an additional sensor is not added, and the current control method is a novel grid-connected control method which is low in cost and high in reliability.

Description

technical field [0001] The invention relates to the field of grid-connected inverter current control, in particular to a single current feedback control method for an LCL type grid-connected inverter. Background technique [0002] Photovoltaic grid-connected inverter is the core device connecting new energy and the grid, and its filtering link is crucial to the quality of output current. Compared with the traditional L-type filter, the LCL filter has been widely used in various large-scale grid-connected inverters due to its advantages of good filtering effect, low cost and small mass. However, since the LCL filter is a third-order system, there is a resonance peak at its resonance frequency, and at the same time, the phase has a -180° jump, which affects the stability of the system and has an adverse effect on the quality of the incoming current. Therefore, in order to ensure the quality of the incoming current, the third-order system of the LCL filter must be calibrated. ...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/38H02M1/12
CPCH02J3/383H02M1/126Y02E10/56
Inventor 廖志凌徐长波崔清华
Owner 江苏谷峰电力科技股份有限公司
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