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Converter rotor side control method and device under unbalanced grid voltage

A grid voltage and control method technology, applied in the direction of generator control circuit, control system, control generator, etc., can solve the problems of rotor-side inverter out of control, high induced electromotive force, overcurrent, etc., and achieve reduction of induced electromotive force, Effect of reducing induced electromotive force and avoiding damage

Inactive Publication Date: 2019-04-12
SANY ELECTRIC CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The traditional PI control strategy cannot effectively suppress the sinusoidal disturbance. Therefore, the rotor current will fluctuate violently, or even over-current. In severe cases, the rotor-side inverter will be burned
[0003] The existing rotor-side converter control method under unbalanced grid voltage requires multiple coordinate transformations and multiple current inner loops. The system structure is relatively complex, and when the grid voltage is unbalanced, the stator flux linkage The negative-sequence component in the rotor affects the rotor flux linkage, thereby generating a high induced electromotive force on the rotor side. When the induced electromotive force on the rotor side exceeds the control capability of the rotor-side converter, the rotor-side inverter will run out of control, resulting in rotor Side overcurrent even burns the rotor side inverter

Method used

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  • Converter rotor side control method and device under unbalanced grid voltage
  • Converter rotor side control method and device under unbalanced grid voltage
  • Converter rotor side control method and device under unbalanced grid voltage

Examples

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no. 1 example

[0053] This embodiment provides a method for controlling the rotor side of the converter under unbalanced grid voltage, please refer to figure 1 , figure 1 A flow chart of the method for controlling the rotor side of the converter under unbalanced grid voltage provided by this embodiment is shown.

[0054] In this embodiment, the method for controlling the rotor side of the converter under unbalanced grid voltage includes steps S10-S40.

[0055] Step S10: Obtain the negative sequence component of the stator voltage.

[0056] Extract the negative sequence component of the stator voltage in the negative sequence coordinate system, and decompose it into the coordinate system through the negative sequence component of the stator voltage to obtain

[0057] In this embodiment, the grid voltage orientation method is adopted. Since the stator voltage is equal to the grid voltage after grid connection, the negative sequence component of the stator in the negative sequence coordinat...

no. 2 example

[0093] This embodiment provides a converter rotor side control device 200 under unbalanced grid voltage, please refer to Figure 8The rotor-side control device 200 of the converter under unbalanced grid voltage includes: an extraction module 210 , a first calculation module 220 , a second calculation module 230 and a drive module 240 .

[0094] An extraction module 210, configured to acquire the negative sequence component of the stator voltage. Extract the negative sequence component of the stator voltage in the negative sequence coordinate system, and decompose it into the coordinate system through the negative sequence component of the stator voltage to obtain

[0095] see Figure 9 , in this embodiment, optionally, the extraction module 210 includes:

[0096] An extraction unit 211, configured to extract the negative sequence component of the grid voltage in the negative sequence coordinate system In this embodiment, the PLL phase-locked loop can be used to separate ...

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Abstract

The invention provides a converter rotor side control method and a device under unbalanced grid voltage. By obtaining the negative sequence component of the stator voltage, the demagnetizing current at the rotor side is calculated, and the demagnetizing current is fed forward to compensate for the current set value of the rotor current, so as to reduce the negative sequence flux linkage at the stator side, thereby reducing the induced electromotive force at the rotor side and preventing the current controller at the rotor side from losing control due to saturation. The control strategy adoptedby the invention is simple in structure and easy to realize in engineering. The demagnetization current injected into the rotor side increases with the increase of the negative sequence component inthe stator voltage, which can effectively reduce the induced electromotive force induced by the negative sequence flux linkage on the rotor side. Thus, even if the power grid voltage is deeply asymmetric, the rotor side current controller will not be out of control due to saturation.

Description

technical field [0001] The invention relates to the technical field of wind power generation, in particular to a method and device for controlling the rotor side of a converter under unbalanced grid voltage. Background technique [0002] For the doubly-fed wind power generation system, when the grid voltage drops asymmetrically, the stator flux linkage will generate a negative sequence component, and a large induced electromotive force will be generated in the rotor circuit of the doubly-fed generator. This induced electromotive force is at the grid voltage synchronization coordinate In the system, it is manifested as a sinusoidal disturbance of twice the grid voltage frequency. The traditional PI control strategy cannot effectively suppress the sinusoidal disturbance. Therefore, the rotor current will fluctuate violently, or even over-current, and in serious cases, the rotor-side inverter will be burned. [0003] The existing rotor-side converter control method under unbal...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02P9/10H02P9/00
CPCH02P9/006H02P9/007H02P9/105
Inventor 刘光欣范科范琳琳
Owner SANY ELECTRIC CO LTD