Grid connected inverter control method with network voltage feedforward lag compensation under weak power grid

A grid voltage and hysteresis compensation technology, which is applied in the direction of single grid parallel feeding arrangement, AC network to reduce harmonic/ripple, harmonic reduction device, etc., can solve the problem of increasing grid-connected current feedback value and command value steady-state error , Grid-connected inverter stability reduction, lower fundamental wave gain and other issues, to achieve the effect of increasing grid adaptability, increasing phase margin, and improving stability

Inactive Publication Date: 2017-08-08
HEFEI UNIV OF TECH
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Problems solved by technology

[0006] (1) For the situation of weak grid, the method of direct feed-forward control of grid voltage in the existing literature will cause the stability of grid-connected inverter to be greatly reduced, and the system stability can be improved by reducing the feed-forward gain of grid voltage, but this method It will reduce the fundamental wave gain and increase the steady-state...

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  • Grid connected inverter control method with network voltage feedforward lag compensation under weak power grid
  • Grid connected inverter control method with network voltage feedforward lag compensation under weak power grid
  • Grid connected inverter control method with network voltage feedforward lag compensation under weak power grid

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Embodiment Construction

[0051] Embodiments of the present invention provide a grid-connected inverter control method with grid voltage feed-forward lag compensation in a weak grid to solve the grid-connected inverter caused by direct feed-forward of grid voltage in the weak grid in the prior art. In order to solve the problem of inverter stability, by adding a low-pass filter link to the grid voltage feedforward channel, it is ensured that the fundamental wave gain of the grid-connected inverter and the grid voltage direct feedforward control are the same, and the fundamental wave is not stable. error tracking. The invention can not only suppress the background harmonics of the grid, but also greatly increase the phase margin of the grid-connected inverter in the case of a weak grid, and improve the grid adaptability of the grid-connected inverter.

[0052] The technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings.

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Abstract

The present invention discloses a grid connected inverter control method with the network voltage feedforward lag compensation under a weak power grid. Aiming at a grid connected inverter stability problem caused by the network voltage direct feedforward on the weak power grid condition, the present invention provides the control method of the network voltage feedforward lag compensation. The method guarantees the situation that the fundamental wave gains of a grid connected inverter and the network voltage direct feedforward control are same in a manner of adding a low-pass filtering link in a network voltage feedforward channel, realizes the astable error tracking of a fundamental wave, not only can inhibit a power grid background harmonic wave, but also enables the phase margin of the grid connected inverter to be increased greatly on the weak power grid, and enables the power grid adaptability of the grid connected inverter to be improved.

Description

technical field [0001] The invention relates to a control method for a grid-connected inverter system, in particular to a control method for a grid-connected inverter with grid voltage feed-forward lag compensation under a weak grid. Background technique [0002] With the rapid development of distributed power generation systems, grid-connected inverters are widely used. In remote distributed power generation systems, the presence of long-distance transmission lines and a large number of transformer devices will bring a non-negligible equivalent impedance to the grid, making the grid show weak grid characteristics. In the case of a weak grid with high impedance, a dynamic interconnection system will be formed between the inverter and the grid. decline, affecting its control stability. The grid-connected inverter adopts the grid voltage direct feed-forward control, which can effectively compensate the current harmonics caused by the grid background harmonics, and thus has b...

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Application Information

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IPC IPC(8): H02J3/38H02J3/01
CPCH02J3/01H02J3/38Y02E40/40
Inventor 张兴李明杨莹张行李飞
Owner HEFEI UNIV OF TECH
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