Reactive power control method of direct-drive fan system when grid voltage drops asymmetrically

A technology of grid voltage and fan system, applied in motor generator control, electronic commutation motor control, multi-phase network asymmetry reduction, etc. Reduced capacity, improved performance, and eliminated the effects of doubling fluctuations

Active Publication Date: 2022-07-05
STATE GRID FUJIAN POWER ELECTRIC CO ECONOMIC RES INST +2
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  • Claims
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Problems solved by technology

In megawatt wind turbines, this kind of power pulsation cannot be ignored. If you only rely on DC capacitors to absorb double-frequency power fluctuations, you need to use larger-capacity capacitors, which will increase the cost and reduce the life of the capacitors, endangering the system. normal operation of

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  • Reactive power control method of direct-drive fan system when grid voltage drops asymmetrically
  • Reactive power control method of direct-drive fan system when grid voltage drops asymmetrically
  • Reactive power control method of direct-drive fan system when grid voltage drops asymmetrically

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Embodiment Construction

[0051] In order to make the features and advantages of this patent more obvious and easy to understand, the following specific examples are given and described in detail as follows:

[0052] like figure 1 As shown, the reactive power control method of the direct-drive fan system when the grid voltage drops asymmetrically provided in this embodiment can be applied to the structure of a typical direct-drive wind power generation system.

[0053] like Figure 2-Figure 4 , Figure 7 As shown, the method specifically includes the following steps:

[0054] (1) Calculate the maximum output power P of the wind turbine according to the wind speed mmax ;

[0055] (2) Calculate the positive and negative sequence dq-axis components of the voltage when the grid voltage drops asymmetrically, allocate the reactive power of the direct-drive fan system according to the requirements of voltage and reactive power control, and calculate the reactive current reference value of the grid-side co...

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Abstract

The invention proposes a reactive power control method for a direct-drive fan system when the grid voltage drops asymmetrically, which calculates the maximum output power of the wind turbine according to the wind speed Pmmax ; Calculate the positive and negative sequence dq-axis components when the grid voltage drops asymmetrically, determine the reactive power of the direct-drive fan system according to the requirements of voltage and reactive power control, and calculate the reactive current reference value of the grid-side converter; Calculate the active current reference value of the grid-side converter according to the maximum output power of the generator and the grid-side reactive current reference value; calculate the active power reference value of the grid-side converter according to the current reference value of the grid-side converter, The reference value controls the rotational speed of the wind turbine so that it operates in the stable operating region of the wind turbine torque-speed characteristic curve. This direct-drive fan system control method can make full use of the reactive power regulation capability of the fan system when the grid voltage drops asymmetrically, and at the same time eliminates the double-frequency fluctuation of the DC side capacitor voltage, realizes a balanced sinusoidal grid-connected current, and improves the system's performance. performance.

Description

technical field [0001] The invention belongs to the technical field of power converters, and in particular relates to a reactive power control method for a direct-drive fan system when the grid voltage drops asymmetrically. Background technique [0002] The direct-drive wind power generation system consists of wind turbines, permanent magnet synchronous generators, full-power power electronic converters, and DC capacitors. Wind turbines directly drive generators to operate at low speeds, eliminating the need for variable-speed gearboxes in traditional wind turbines and improving reliability. The generator and the grid are directly connected through the full-power power electronic converter, which realizes the independent control of active and reactive power on the grid side, and improves the low-voltage ride-through capability under faults. Permanent magnet direct-drive wind turbines are attracting more and more attention in offshore wind power due to their high reliability...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02J3/50H02J3/48H02J3/16H02J3/24H02J3/26H02P9/00H02P21/00
CPCH02J3/50H02J3/48H02J3/16H02J3/24H02J3/26H02P9/00H02P21/00H02J2300/28H02P2101/15Y02E40/50
Inventor 林伟伟叶荣林毅黄海方朝雄唐雨晨冯双汤奕
Owner STATE GRID FUJIAN POWER ELECTRIC CO ECONOMIC RES INST
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