CN-122001251-A - Control method, control device, converter and doubly-fed power generation system

CN122001251ACN 122001251 ACN122001251 ACN 122001251ACN-122001251-A

Abstract

The application discloses a control method, a control device, a converter and a doubly-fed power generation system, and belongs to the technical field of power generation. The method is used for a first converter, a direct current end of the first converter is connected with a direct current bus of a double-fed converter, an alternating current end of the first converter is connected with a stator end of a generator set, one end of the double-fed converter is connected with a rotor end of the generator set, the other end of the double-fed converter is connected with a power grid, the method comprises the steps of obtaining a voltage fluctuation value of the direct current bus, obtaining a target current value corresponding to the voltage fluctuation value, and controlling current output of the alternating current end of the first converter based on the target current value. The method can obviously improve the stability of the direct current bus and enhance the safety and stability of the operation of the generator set under the working condition of a complex power grid.

Inventors

WU YUYANG
XIE ZHEN
LIANG XINXIN
YANG SHUYING

Assignees

合肥工业大学
阳光电源股份有限公司

Dates

Publication Date: 20260508
Application Date: 20260407

Claims (14)

1. The control method is used for a first current transformer, wherein a direct current end of the first current transformer is connected with a direct current bus of a double-fed current transformer, an alternating current end of the first current transformer is connected with a stator end of a generator set, one end of the double-fed current transformer is connected with a rotor end of the generator set, and the other end of the double-fed current transformer is connected with a power grid, and the method comprises the following steps: Acquiring a voltage fluctuation value of the direct current bus; Acquiring a target current value corresponding to the voltage fluctuation value; And controlling the current output of the alternating-current end of the first converter based on the target current value.
2. The control method according to claim 1, characterized in that the obtaining a target current value corresponding to the voltage fluctuation value includes: Comparing the voltage fluctuation value with a preset voltage threshold value; Executing a first detection mode under the condition that the voltage fluctuation value is smaller than the preset voltage threshold value, and acquiring the target current value; Or executing a second detection mode to acquire the target current value under the condition that the voltage fluctuation value is larger than or equal to the preset voltage threshold value.
3. The control method according to claim 2, wherein the performing the first detection mode to acquire the target current value includes: Acquiring a voltage ripple component of the direct current bus, a direct current value of a direct current end of the first converter and a stator voltage value of the generator set; the target current value is determined based on the voltage ripple component, the direct current value, and the stator voltage value.
4. A control method according to claim 3, wherein the voltage ripple component is extracted by a second-order generalized integrator, the voltage ripple component of the output of the second-order generalized integrator comprising a ripple in-phase component and a ripple quadrature component.
5. The control method according to claim 3, characterized in that the determining the target current value based on the voltage ripple component, the direct current value, and the stator voltage value includes: Applying the formula Wherein, the For the target current value, the voltage ripple component includes 、 , As the in-phase component of the ripple, As the orthogonal component of the ripple, For the dc value of the dc end of the first converter, Is the stator voltage value of the generator set.
6. The control method according to claim 2, characterized in that the performing the second detection mode, acquiring the target current value, includes: Acquiring a bus capacitance value of the direct current bus, a direct current voltage value of a direct current end of the first converter and an alternating current voltage value of an alternating current end; The target current value is determined based on the voltage fluctuation value, the bus capacitance value, the direct current voltage value, and the alternating current voltage value.
7. The control method according to any one of claims 2 to 6, characterized in that the preset voltage threshold is determined based on a rated bus voltage of the direct current bus, the preset voltage threshold being smaller than the rated bus voltage.
8. The control method according to claim 7, characterized in that the preset voltage threshold is 1-10% of the nominal bus voltage.
9. The control method according to any one of claims 1 to 6, characterized in that the controlling the current output of the ac terminal of the first converter based on the target current value includes: acquiring an alternating current value of an alternating current end of the first converter; Generating a voltage instruction by taking the target current value as a reference value and the alternating current value as a feedback value; and performing coordinate transformation and pulse width modulation based on the voltage command to generate a driving signal of the first converter, wherein the driving signal is used for driving the first converter to control output current.
10. The control device is used for a first current transformer, wherein a direct current end of the first current transformer is connected with a direct current bus of a double-fed current transformer, an alternating current end of the first current transformer is connected with a stator end of a generator set, one end of the double-fed current transformer is connected with a rotor end of the generator set, and the other end of the double-fed current transformer is connected with a power grid, and the device comprises: The first processing module is used for acquiring the voltage fluctuation value of the direct current bus; the second processing module is used for acquiring a target current value corresponding to the voltage fluctuation value; and the third processing module is used for controlling the current output of the alternating-current end of the first converter based on the target current value.
11. A current transformer, comprising: The control device according to claim 10, wherein the DC end of the converter is connected with a DC bus of a doubly-fed converter, the AC end of the converter is connected with a stator end of a generator set, one end of the doubly-fed converter is connected with a rotor end of the generator set, and the other end of the doubly-fed converter is connected with a power grid.
12. A doubly-fed power generation system, comprising: the power generation unit, the double-fed current transformer and the first current transformer; The direct current end of the first current transformer is connected with the direct current bus of the double-fed current transformer, and the alternating current end of the first current transformer is connected with the stator end of the generator set; Wherein the first converter comprises a control device according to claim 10.
13. An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, characterized in that the processor implements the control method according to any one of claims 1-9 when executing the program.
14. A non-transitory computer readable storage medium, on which a computer program is stored, characterized in that the computer program, when executed by a processor, implements the control method according to any one of claims 1-9.

Description

Control method, control device, converter and doubly-fed power generation system Technical Field The application belongs to the technical field of power generation, and particularly relates to a control method, a control device, a converter and a doubly-fed power generation system. Background The doubly-fed induction generator (DFIG) is a generator type widely applied in the field of wind power generation, a stator winding of the DFIG is directly connected with a power grid, and a rotor winding is connected with the power grid through a doubly-fed converter, so that efficient grid-connected power transmission is realized. However, the machine set is extremely sensitive to power grid disturbance, and when the power grid is subjected to transient working conditions such as voltage drop, harmonic disturbance or frequency fluctuation, the disturbance can be directly transmitted to the rotor winding through the stator winding. On the one hand, the disturbance on the stator side can directly influence the running stability of the generator in the transient process, so that the control precision is reduced, and the dynamic response is retarded. On the other hand, rotor side power impact caused by power grid disturbance can directly act on a DC bus of the converter to damage power balance in the converter, so that severe fluctuation of DC bus voltage is caused, DC overvoltage and undervoltage protection actions can be triggered, and a machine set off-grid accident can be seriously caused. Disclosure of Invention The present invention aims to solve at least one of the technical problems existing in the prior art. Therefore, the control method, the control device, the converter and the doubly-fed power generation system can improve the stability of the direct current bus of the converter and are beneficial to safe and stable operation of the generator set under the working condition of a complex power grid. In a first aspect, the application provides a control method, which is used for a first current transformer, wherein a direct current end of the first current transformer is connected with a direct current bus of a double-fed current transformer, an alternating current end of the first current transformer is connected with a stator end of a generator set, one end of the double-fed current transformer is connected with a rotor end of the generator set, and the other end of the double-fed current transformer is connected with a power grid, and the method comprises the following steps: Acquiring a voltage fluctuation value of the direct current bus; Acquiring a target current value corresponding to the voltage fluctuation value; And controlling the current output of the alternating-current end of the first converter based on the target current value. According to the control method, the current operation condition type of the system is judged by acquiring the voltage fluctuation value of the direct current bus, the corresponding target current value is calculated, the alternating current end of the first converter is connected with the stator end of the generator set, the topological structure can reduce the direct current coupling influence of the stator end fluctuation on the doubly-fed converter, the current output of the alternating current end of the first converter is controlled according to the target current value, the stability of the direct current bus can be obviously improved, and the operation safety and stability of the generator set under the complex power grid condition are enhanced. According to an embodiment of the present application, the acquiring a target current value corresponding to the voltage fluctuation value includes: Comparing the voltage fluctuation value with a preset voltage threshold value; Executing a first detection mode under the condition that the voltage fluctuation value is smaller than the preset voltage threshold value, and acquiring the target current value; Or executing a second detection mode to acquire the target current value under the condition that the voltage fluctuation value is larger than or equal to the preset voltage threshold value. According to one embodiment of the present application, the performing the first detection mode, obtaining the target current value, includes: Acquiring a voltage ripple component of the direct current bus, a direct current value of a direct current end of the first converter and a stator voltage value of the generator set; the target current value is determined based on the voltage ripple component, the direct current value, and the stator voltage value. According to one embodiment of the application, the voltage ripple component is extracted by a second-order generalized integrator, and the voltage ripple component of the output of the second-order generalized integrator comprises a ripple in-phase component and a ripple quadrature component. According to an embodiment of the present application, the determining the target current v