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Order increasing grid-connected converter transient state network voltage feed-forward item low-pass filter method

A technology of low-pass filtering and low-pass filter, which is applied to the AC network to reduce harmonics/ripples, harmonic reduction devices, etc., can solve problems such as large disturbances, large voltage feedforward errors, and poor control characteristics, and achieve Accurate acquisition and quick response to the effect

Inactive Publication Date: 2015-05-06
南京国电南自风电自动化技术有限公司
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Problems solved by technology

[0004] Aiming at the above-mentioned technical problems, the present invention captures the transient points of the grid voltage, enables the order-increasing algorithm, and realizes the low-pass filtering of each component of the positive and negative sequence voltages in the synchronously rotating DC coordinate system during the transient process. Fast response, and at the same time realize the rapid increase of the harmonic attenuation coefficient after the voltage transient, and can quickly and accurately obtain the grid voltage feed-forward item in the positive and negative sequence control equations of the synchronous rotating DC coordinate system to solve the problem of doubly-fed wind power generation system. Technical problems of grid voltage feed-forward errors, large disturbances, and poor control characteristics during low-voltage ride-through of side converters

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  • Order increasing grid-connected converter transient state network voltage feed-forward item low-pass filter method
  • Order increasing grid-connected converter transient state network voltage feed-forward item low-pass filter method
  • Order increasing grid-connected converter transient state network voltage feed-forward item low-pass filter method

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Embodiment Construction

[0020] The present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments.

[0021] Step (1), such as figure 1 As shown in the zero-crossing capture diagram of phase A grid voltage sampling in the present invention, the phase A grid voltage is sampled to obtain u A , put u A LPF through low pass filter frequency get u A . FilterLPF frequency The transfer function of is: Its cut-off frequency is 50Hz. to u A Implement zero-crossing capture when u′ A The moment of change from negative value to positive value is defined as the capture point. At the capture point, let θ p = θ n = 0, before the next capture point, for θ p with theta n Calculate the angle to get: θ p =100π×t, θ n =-100π×t. where t is the time (in seconds) after the capture point, θ p is the angle between the d-axis of the positive sequence DC rotating coordinate system and the phase A of the three-phase stationary coordinate system...

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Abstract

The invention discloses an order increasing grid-connected converter transient state network voltage feed-forward item low-pass filter method, wherein an order increasing algorithm is enabled by capturing a network voltage transient point; quick response to a network voltage feed-forward item in a transient process is realized and meanwhile increasing of a harmonic attenuation coefficient along with the passage of time at a voltage transient moment is realized when low-pass filter is performed on each component of positive and negative sequence voltage of a synchronous rotary direct current coordinate system; and quick and accurate acquisition of the network voltage feed-forward item in a positive and negative sequence control equation of the synchronous rotary direct current coordinate system is realized.

Description

technical field [0001] The invention belongs to the technical field of power electronics applications, and in particular relates to a low-pass filtering method for a transient network voltage feedforward term of a grid-connected converter with increasing orders. Background technique [0002] With the development of power electronics technology and fast digital signal processing technology, doubly-fed wind power generation system has been widely used. However, due to the operating conditions such as instantaneous voltage drop, instantaneous recovery, and harmonic disturbance caused by grid faults, the low voltage ride-through control and fast response control of reactive current of the double-fed wind power generation system grid-side converter become difficult. [0003] When the voltage drop occurs in the power grid connected to the double-fed wind turbine, the amplitude and phase of the fundamental wave of the grid voltage will undergo transient changes, resulting in a sign...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02J3/01
CPCY02E40/40
Inventor 骆皓肖遥曹阳郭巍孙永佳姚广秀郑东山庄俊
Owner 南京国电南自风电自动化技术有限公司
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