Oscillation suppression method and device for new energy flexible direct current interconnection system

Abstract

The invention provides a new energy flexible direct current interconnection system oscillation suppression method and device. The oscillation of the new energy flexible direct current interconnection system can be suppressed according to the fundamental wave modulation voltage of the energy storage converter under the three-phase static coordinate system and the oscillation suppression voltage of the energy storage converter under the three-phase static coordinate system, the oscillation suppression difficulty is reduced, the practicability of the suppression method is improved, and effective suppression of the oscillation is realized. On the basis of not changing the structure of the flexible direct-current interconnection system, oscillation suppression is realized, the improvement of the oscillation suppression effect is ensured, the operation performance of the new energy station and the flexible direct-current power transmission system is not influenced, the problems of equipment damage or new energy unit off-network and the like are avoided, and the service life of the new energy station and the flexible direct-current power transmission system is prolonged. And the operation stability and reliability of the flexible direct current interconnection system are improved.

Description

Technical Field

[0001] This application relates to the field of new energy technology, specifically to a method and apparatus for oscillation suppression in a new energy flexible DC interconnection system. Background Technology

[0002] Flexible DC transmission systems for renewable energy integration (i.e., renewable flexible DC interconnection systems) have become the best means to solve the problem of large-scale long-distance transmission and consumption of renewable energy due to their advantages such as no need for commutation voltage and flexible control. Wind power, photovoltaic power, and flexible DC converters are complex to control, operate at high speeds, and have control frequency bands reaching several kilohertz, which can easily induce wide-frequency oscillations in renewable flexible DC interconnection systems. According to impedance stability theory, this can be attributed to the lack of damping in the renewable flexible DC interconnection system at a certain non-fundamental frequency.

[0003] Related technologies typically suppress oscillations in flexible DC interconnection systems by adjusting the damping characteristics on the renewable energy side or the damping characteristics on the flexible DC converter side. However, renewable energy power plants (such as wind farms) usually contain a large number of wind turbines. Optimizing the impedance characteristics of the entire wind farm by adjusting the impedance characteristics of each individual wind turbine is difficult due to the interaction between the wind turbines, resulting in poor practicality and effectiveness of the suppression methods. Summary of the Invention

[0004] To address the issues of poor practicality and effectiveness of existing suppression methods, this application provides a method and apparatus for suppressing oscillations in a new energy flexible DC interconnect system.

[0005] In a first aspect, this application provides a method for suppressing oscillations in a new energy flexible DC interconnect system, which may include: The actual output current of the energy storage converter is controlled based on the active power reference value and reactive power reference value of the energy storage converter to obtain the fundamental modulation voltage of the energy storage converter in the three-phase stationary coordinate system.

[0006] The oscillation suppression voltage of the energy storage converter in the three-phase stationary coordinate system is calculated based on the actual three-phase voltage value at the grid connection point of the new energy power station and the actual output current value of the energy storage converter.

[0007] The oscillations of the new energy flexible DC interconnection system are suppressed by using the fundamental modulation voltage of the energy storage converter in the three-phase stationary coordinate system and the oscillation suppression voltage of the energy storage converter in the three-phase stationary coordinate system.

[0008] In some possible implementations, the actual output current of the energy storage converter is controlled based on the active power reference value and reactive power reference value of the energy storage converter to obtain the fundamental modulation voltage of the energy storage converter in a three-phase stationary coordinate system, including: Phase-locked loop control is performed on the actual three-phase voltage values ​​at the grid connection point of the new energy power plant to obtain the synchronous phase of the power grid connected to the new energy flexible DC interconnection system.

[0009] The modulation voltage of the energy storage converter in a two-phase rotating coordinate system is output based on the synchronous phase of the power grid, the active power reference value of the energy storage converter, the reactive power reference value of the energy storage converter, and the actual output current value of the energy storage converter.

[0010] Based on the synchronous phase of the power grid, the modulation voltage of the energy storage converter in the two-phase rotating coordinate system is subjected to inverse Park transform to obtain the fundamental modulation voltage of the energy storage converter in the three-phase stationary coordinate system.

[0011] Furthermore, based on the grid's synchronous phase, the active power reference value of the energy storage converter, the reactive power reference value of the energy storage converter, and the actual output current value of the energy storage converter, the modulation voltage of the energy storage converter in a two-phase rotating coordinate system is output, including: By performing a Parker transformation on the actual output current of the energy storage converter, the actual d-axis output current and q-axis output current of the energy storage converter in a two-phase rotating coordinate system are obtained.

[0012] Calculate the d-axis output voltage of the energy storage converter in a two-phase rotating coordinate system based on the active power reference value and the actual d-axis output current value of the energy storage converter in the two-phase rotating coordinate system. Calculate the q-axis output voltage of the energy storage converter in a two-phase rotating coordinate system based on the reactive power reference value and the actual q-axis output current value of the energy storage converter in the two-phase rotating coordinate system.

[0013] Calculate the d-axis decoupling voltage of the energy storage converter in a two-phase rotating coordinate system based on the actual d-axis output current value of the energy storage converter in the two-phase rotating coordinate system. Calculate the q-axis decoupling voltage of the energy storage converter in a two-phase rotating coordinate system based on the actual q-axis output current value of the energy storage converter in the two-phase rotating coordinate system.

[0014] The difference between the d-axis output voltage and the q-axis decoupling voltage of the energy storage converter in a two-phase rotating coordinate system is taken as the d-axis modulation voltage of the energy storage converter in a two-phase rotating coordinate system. The q-axis modulation voltage of the energy storage converter in a two-phase rotating coordinate system is obtained by superimposing the q-axis output voltage and the d-axis decoupling voltage of the energy storage converter in a two-phase rotating coordinate system.

[0015] Optionally, the d-axis output voltage of the energy storage converter in the two-phase rotating coordinate system is calculated based on the active power reference value of the energy storage converter and the actual value of the d-axis output current of the energy storage converter in the two-phase rotating coordinate system, including: The difference between the active power reference value and the actual active power value of the energy storage converter is used for proportional-integral control to obtain the d-axis current reference value of the energy storage converter in a two-phase rotating coordinate system.

[0016] The difference between the reference value of the d-axis current of the energy storage converter in the two-phase rotating coordinate system and the actual value of the d-axis output current of the energy storage converter in the two-phase rotating coordinate system is used for proportional-integral control to obtain the d-axis output voltage of the energy storage converter in the two-phase rotating coordinate system.

[0017] Calculate the q-axis output voltage of the energy storage converter in the two-phase rotating coordinate system based on the reference value of the reactive power of the energy storage converter and the actual value of the q-axis output current of the energy storage converter in the two-phase rotating coordinate system, including: The difference between the reactive power reference value and the actual reactive power value of the energy storage converter is used for proportional-integral control to obtain the q-axis current reference value of the energy storage converter in a two-phase rotating coordinate system.

[0018] The difference between the reference value of the q-axis current of the energy storage converter in the two-phase rotating coordinate system and the actual value of the q-axis output current of the energy storage converter in the two-phase rotating coordinate system is used for proportional-integral control to obtain the q-axis output voltage of the energy storage converter in the two-phase rotating coordinate system.

[0019] For example, the d-axis decoupling voltage of the energy storage converter in a two-phase rotating coordinate system satisfies ,in, This represents the d-axis decoupling voltage of the energy storage converter in a two-phase rotating coordinate system. This represents the actual d-axis output current of the energy storage converter in a two-phase rotating coordinate system. Indicates the power frequency angular frequency. This indicates the inductance value of the grid-connected inductor of the energy storage converter.

[0020] The q-axis decoupling voltage of the energy storage converter in a two-phase rotating coordinate system satisfies: ,in, This represents the q-axis decoupling voltage of the energy storage converter in a two-phase rotating coordinate system. Actual value of q-axis output current of the energy storage converter in a two-phase rotating coordinate system.

[0021] In other possible implementations, the oscillation suppression voltage of the energy storage converter in the three-phase stationary coordinate system is calculated based on the actual three-phase voltage at the grid connection point of the new energy power station and the actual output current of the energy storage converter, including: The reference value of the oscillation suppression current of the energy storage converter in the two-phase stationary coordinate system is determined based on the actual value of the three-phase voltage at the grid connection point of the new energy power station.

[0022] The oscillation compensation voltage of the energy storage converter in the two-phase stationary coordinate system is determined based on the actual output current value of the energy storage converter and the reference value of the oscillation suppression current of the energy storage converter in the two-phase stationary coordinate system.

[0023] By performing an inverse Clarke transformation on the oscillation compensation voltage of the energy storage converter in the two-phase stationary coordinate system, the oscillation suppression voltage of the energy storage converter in the three-phase stationary coordinate system can be obtained.

[0024] Furthermore, based on the actual three-phase voltage values ​​at the grid connection point of the new energy power plant, the reference value for the oscillation suppression current of the energy storage converter in the two-phase stationary coordinate system is determined, including: The actual three-phase voltage values ​​at the grid connection point of the new energy power station are subjected to Clark transformation to obtain the actual α-axis voltage values ​​and β-axis voltage values ​​at the grid connection point of the new energy power station in a two-phase stationary coordinate system.

[0025] The difference between a preset α-axis voltage reference value and the actual α-axis voltage value at the grid connection point of the renewable energy power station in a two-phase stationary coordinate system is used for proportional resonant control to obtain the α-axis oscillation suppression current reference value of the energy storage converter in a two-phase stationary coordinate system. Similarly, the difference between a preset β-axis voltage reference value and the actual β-axis voltage value at the grid connection point of the renewable energy power station in a two-phase stationary coordinate system is used for proportional resonant control to obtain the β-axis oscillation suppression current reference value of the energy storage converter in a two-phase stationary coordinate system.

[0026] Optionally, the oscillation compensation voltage of the energy storage converter in the two-phase stationary coordinate system is determined based on the actual output current value of the energy storage converter and the reference value of the oscillation suppression current of the energy storage converter in the two-phase stationary coordinate system, including: By performing a Clarke transformation on the actual output current of the energy storage converter, the actual α-axis current and β-axis current of the energy storage converter in a two-phase stationary coordinate system are obtained.

[0027] The difference between the reference value of the α-axis oscillation suppression current of the energy storage converter in the two-phase stationary coordinate system and the actual value of the α-axis current of the energy storage converter in the two-phase stationary coordinate system is used for proportional resonance control to obtain the α-axis oscillation compensation voltage of the energy storage converter in the two-phase stationary coordinate system.

[0028] The difference between the reference value of the β-axis oscillation suppression current of the energy storage converter in the two-phase stationary coordinate system and the actual value of the β-axis current of the energy storage converter in the two-phase stationary coordinate system is used for proportional resonance control to obtain the β-axis oscillation compensation voltage of the energy storage converter in the two-phase stationary coordinate system.

[0029] In some other possible implementations, oscillations in the new energy flexible DC interconnection system are suppressed based on the fundamental modulation voltage of the energy storage converter in the three-phase stationary coordinate system and the oscillation suppression voltage of the energy storage converter in the three-phase stationary coordinate system, including: The control voltage of the energy storage converter in the three-phase stationary coordinate system is obtained by superimposing the fundamental modulation voltage of the energy storage converter in the three-phase stationary coordinate system and the oscillation suppression voltage of the energy storage converter in the three-phase stationary coordinate system.

[0030] The control voltage of the energy storage converter in the three-phase stationary coordinate system is modulated to obtain a control signal, and the energy storage converter is controlled according to the control signal.

[0031] Optionally, oscillation suppression methods also include: Fourier transform is performed on the actual three-phase voltage values ​​of the grid-connected points of new energy power plants to obtain the voltage amplitudes of the grid-connected points of new energy power plants at different frequencies.

[0032] If the voltage amplitude at the grid connection point of a new energy power station exceeds a preset voltage threshold at different frequencies, it is determined that the new energy flexible DC interconnection system is oscillating.

[0033] Secondly, this application provides an oscillation suppression device for a new energy flexible DC interconnect system, which may include: The control module is used to control the actual output current of the energy storage converter based on the active power reference value and reactive power reference value of the energy storage converter, so as to obtain the fundamental modulation voltage of the energy storage converter in the three-phase stationary coordinate system.

[0034] The calculation module is used to calculate the oscillation suppression voltage of the energy storage converter in the three-phase stationary coordinate system based on the actual value of the three-phase voltage at the grid connection point of the new energy power station and the actual value of the output current of the energy storage converter.

[0035] The suppression module is used to suppress the oscillations that occur in the new energy flexible DC interconnection system based on the fundamental modulation voltage of the energy storage converter in the three-phase stationary coordinate system and the oscillation suppression voltage of the energy storage converter in the three-phase stationary coordinate system.

[0036] In some possible implementations, the control module is specifically used for: Phase-locked loop control is performed on the actual three-phase voltage values ​​at the grid connection point of the new energy power plant to obtain the synchronous phase of the power grid connected to the new energy flexible DC interconnection system.

[0037] The modulation voltage of the energy storage converter in a two-phase rotating coordinate system is output based on the synchronous phase of the power grid, the active power reference value of the energy storage converter, the reactive power reference value of the energy storage converter, and the actual output current value of the energy storage converter.

[0038] Based on the synchronous phase of the power grid, the modulation voltage of the energy storage converter in the two-phase rotating coordinate system is subjected to inverse Park transform to obtain the fundamental modulation voltage of the energy storage converter in the three-phase stationary coordinate system.

[0039] Furthermore, the control module is specifically used for: By performing a Parker transformation on the actual output current of the energy storage converter, the actual d-axis output current and q-axis output current of the energy storage converter in a two-phase rotating coordinate system are obtained.

[0040] Calculate the d-axis output voltage of the energy storage converter in a two-phase rotating coordinate system based on the active power reference value and the actual d-axis output current value of the energy storage converter in the two-phase rotating coordinate system. Calculate the q-axis output voltage of the energy storage converter in a two-phase rotating coordinate system based on the reactive power reference value and the actual q-axis output current value of the energy storage converter in the two-phase rotating coordinate system.

[0041] Calculate the d-axis decoupling voltage of the energy storage converter in a two-phase rotating coordinate system based on the actual d-axis output current value of the energy storage converter in the two-phase rotating coordinate system. Calculate the q-axis decoupling voltage of the energy storage converter in a two-phase rotating coordinate system based on the actual q-axis output current value of the energy storage converter in the two-phase rotating coordinate system.

[0042] The difference between the d-axis output voltage and the q-axis decoupling voltage of the energy storage converter in a two-phase rotating coordinate system is taken as the d-axis modulation voltage of the energy storage converter in a two-phase rotating coordinate system. The q-axis modulation voltage of the energy storage converter in a two-phase rotating coordinate system is obtained by superimposing the q-axis output voltage and the d-axis decoupling voltage of the energy storage converter in a two-phase rotating coordinate system.

[0043] Optionally, the control module is specifically used for: The difference between the active power reference value and the actual active power value of the energy storage converter is used for proportional-integral control to obtain the d-axis current reference value of the energy storage converter in a two-phase rotating coordinate system.

[0044] The difference between the reference value of the d-axis current of the energy storage converter in the two-phase rotating coordinate system and the actual value of the d-axis output current of the energy storage converter in the two-phase rotating coordinate system is used for proportional-integral control to obtain the d-axis output voltage of the energy storage converter in the two-phase rotating coordinate system.

[0045] For example, the control module is specifically used for: The difference between the reactive power reference value and the actual reactive power value of the energy storage converter is used for proportional-integral control to obtain the q-axis current reference value of the energy storage converter in a two-phase rotating coordinate system.

[0046] The difference between the reference value of the q-axis current of the energy storage converter in the two-phase rotating coordinate system and the actual value of the q-axis output current of the energy storage converter in the two-phase rotating coordinate system is used for proportional-integral control to obtain the q-axis output voltage of the energy storage converter in the two-phase rotating coordinate system.

[0047] The d-axis decoupling voltage of the energy storage converter in a two-phase rotating coordinate system satisfies ,in, This represents the d-axis decoupling voltage of the energy storage converter in a two-phase rotating coordinate system. This represents the actual d-axis output current of the energy storage converter in a two-phase rotating coordinate system. Indicates the power frequency angular frequency. This indicates the inductance value of the grid-connected inductor of the energy storage converter.

[0048] The q-axis decoupling voltage of the energy storage converter in a two-phase rotating coordinate system satisfies: ,in, This represents the q-axis decoupling voltage of the energy storage converter in a two-phase rotating coordinate system. Actual value of q-axis output current of the energy storage converter in a two-phase rotating coordinate system.

[0049] In some other possible implementations, the computation module is specifically used for: The reference value of the oscillation suppression current of the energy storage converter in the two-phase stationary coordinate system is determined based on the actual value of the three-phase voltage at the grid connection point of the new energy power station.

[0050] The oscillation compensation voltage of the energy storage converter in the two-phase stationary coordinate system is determined based on the actual output current value of the energy storage converter and the reference value of the oscillation suppression current of the energy storage converter in the two-phase stationary coordinate system.

[0051] By performing an inverse Clarke transformation on the oscillation compensation voltage of the energy storage converter in the two-phase stationary coordinate system, the oscillation suppression voltage of the energy storage converter in the three-phase stationary coordinate system can be obtained.

[0052] Optionally, the calculation module is specifically used for: The actual three-phase voltage values ​​at the grid connection point of the new energy power station are subjected to Clark transformation to obtain the actual α-axis voltage values ​​and β-axis voltage values ​​at the grid connection point of the new energy power station in a two-phase stationary coordinate system.

[0053] The difference between a preset α-axis voltage reference value and the actual α-axis voltage value at the grid connection point of the renewable energy power station in a two-phase stationary coordinate system is used for proportional resonant control to obtain the α-axis oscillation suppression current reference value of the energy storage converter in a two-phase stationary coordinate system. Similarly, the difference between a preset β-axis voltage reference value and the actual β-axis voltage value at the grid connection point of the renewable energy power station in a two-phase stationary coordinate system is used for proportional resonant control to obtain the β-axis oscillation suppression current reference value of the energy storage converter in a two-phase stationary coordinate system.

[0054] For example, the calculation module is specifically used for: By performing a Clarke transformation on the actual output current of the energy storage converter, the actual α-axis current and β-axis current of the energy storage converter in a two-phase stationary coordinate system are obtained.

[0055] The difference between the reference value of the α-axis oscillation suppression current of the energy storage converter in the two-phase stationary coordinate system and the actual value of the α-axis current of the energy storage converter in the two-phase stationary coordinate system is used for proportional resonance control to obtain the α-axis oscillation compensation voltage of the energy storage converter in the two-phase stationary coordinate system.

[0056] The difference between the reference value of the β-axis oscillation suppression current of the energy storage converter in the two-phase stationary coordinate system and the actual value of the β-axis current of the energy storage converter in the two-phase stationary coordinate system is used for proportional resonance control to obtain the β-axis oscillation compensation voltage of the energy storage converter in the two-phase stationary coordinate system.

[0057] In some other possible implementations, the suppression module is specifically used for: The control voltage of the energy storage converter in the three-phase stationary coordinate system is obtained by superimposing the fundamental modulation voltage of the energy storage converter in the three-phase stationary coordinate system and the oscillation suppression voltage of the energy storage converter in the three-phase stationary coordinate system.

[0058] The control voltage of the energy storage converter in the three-phase stationary coordinate system is modulated to obtain a control signal, and the energy storage converter is controlled according to the control signal.

[0059] Optionally, the oscillation suppression device further includes a determination module. The determination module is used for: Fourier transform is performed on the actual three-phase voltage values ​​of the grid-connected points of new energy power plants to obtain the voltage amplitudes of the grid-connected points of new energy power plants at different frequencies.

[0060] If the voltage amplitude at the grid connection point of a new energy power station exceeds a preset voltage threshold at different frequencies, it is determined that the new energy flexible DC interconnection system is oscillating.

[0061] In another aspect, this application also provides a computer device, including: one or more processors.

[0062] A processor is used to execute one or more programs.

[0063] When one or more programs are executed by one or more processors, the oscillation suppression method described above is implemented.

[0064] Furthermore, this application also provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed, it implements the oscillation suppression method described above.

[0065] Compared with the prior art, the beneficial effects of this application are as follows: The oscillation suppression method for a new energy flexible DC interconnection system provided in this application controls the actual output current of the energy storage converter based on its active and reactive power reference values, thereby obtaining the fundamental modulation voltage of the energy storage converter in a three-phase stationary coordinate system. The oscillation suppression voltage of the energy storage converter in a three-phase stationary coordinate system is calculated based on the actual three-phase voltage at the grid connection point of the new energy power station and the actual output current of the energy storage converter. Oscillations occurring in the new energy flexible DC interconnection system are suppressed based on the fundamental modulation voltage and the oscillation suppression voltage of the energy storage converter in a three-phase stationary coordinate system. This application achieves oscillation suppression of the new energy flexible DC interconnection system through the oscillation suppression voltage of the energy storage converter in a three-phase stationary coordinate system, reducing the difficulty of oscillation suppression, improving the practicality of the suppression method, and achieving effective oscillation suppression.

[0066] This application achieves oscillation suppression without changing the structure of the flexible DC interconnection system. This not only ensures improved oscillation suppression effect, but also does not affect the operational performance of new energy power plants and flexible DC transmission systems. It avoids problems such as equipment damage or grid disconnection of new energy units due to failure of fault ride-through in the flexible DC interconnection system, thereby improving the operational stability and reliability of the flexible DC interconnection system.

[0067] This application allows for setting the frequency range and frequency interval during the actual three-phase voltage acquisition process of new energy power station grid connection points according to actual needs, and can simultaneously suppress oscillations at multiple frequencies, adapting to various operating conditions, with high flexibility and strong adaptability.

[0068] In this application, the energy storage device not only performs its main functions such as power support, but also takes into account the oscillation suppression of the flexible DC interconnection system, thereby improving the utilization efficiency of the energy storage device and the economy of the entire flexible DC interconnection system.

[0069] The oscillation suppression method provided in this application has good scalability and can be easily connected to flexible DC interconnection systems. It is suitable for the expansion or structural changes of flexible DC interconnection systems and has broad application prospects. Attached Figure Description

[0070] To more clearly illustrate the technical solutions in this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0071] Figure 1 This is a schematic structural diagram of a new energy flexible DC interconnection system in the embodiments of this application; Figure 2This is a schematic flowchart of an oscillation suppression method for a new energy flexible DC interconnection system in this application embodiment; Figure 3 This is a schematic flowchart illustrating the fundamental modulation voltage of the energy storage converter in a three-phase stationary coordinate system as described in this application embodiment. Figure 4 This is a schematic flowchart illustrating the calculation of the oscillation suppression voltage of the energy storage converter in a three-phase stationary coordinate system in an embodiment of this application. Figure 5 This is a schematic flowchart illustrating the suppression of oscillations in a new energy flexible DC interconnection system as described in this application. Figure 6 This is a schematic structural diagram of an oscillation suppression device for a new energy flexible DC interconnection system in an embodiment of this application. Detailed Implementation

[0072] The technical solutions in this application will now be described with reference to the accompanying drawings.

[0073] The terms "first," "second," etc., used in the specification, embodiments, claims, and drawings of this application are for distinguishing purposes only and should not be construed as indicating or implying relative importance or order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion, such as including a series of steps or units. A method, system, product, or apparatus is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products, or apparatuses.

[0074] It should be understood that in this application, "at least one (item)" means one or more, and "more than" means two or more. "And / or" is used to describe the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent three cases: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one (item) of a, b, or c can represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0075] Example 1: This application provides an embodiment of a method for suppressing oscillations in a new energy flexible DC interconnect system. For example... Figure 1As shown, the new energy flexible DC interconnection system 100 may include a new energy power station 10 (which may be a wind farm or photovoltaic, etc.), energy storage equipment 20, and a flexible DC transmission system 30. The new energy power station 10 and the energy storage equipment 20 are connected to the flexible DC transmission system 30 through a grid connection point (i.e., a PPC point). The flexible DC transmission system 30 may include a flexible DC converter (which may be a voltage source converter, VSC), etc. The energy storage equipment 20 may include an energy storage battery pack 201 and an energy storage converter 202. The energy storage converter 202 may be a two-level structure energy storage converter, etc. Each bridge arm may include multiple cascaded sub-modules. Figure 1 middle, i abc This indicates the actual value of the output current of the energy storage converter. u pcc This indicates the actual value of the three-phase voltage at the grid connection point of the new energy power station.

[0076] like Figure 2 As shown, the oscillation suppression method 200 includes the following steps: Step S1: Control the actual output current of the energy storage converter according to the active power reference value and reactive power reference value of the energy storage converter to obtain the fundamental modulation voltage of the energy storage converter in the three-phase stationary coordinate system.

[0077] Step S2: Calculate the oscillation suppression voltage of the energy storage converter in the three-phase stationary coordinate system based on the actual three-phase voltage value of the grid connection point of the new energy power station and the actual output current value of the energy storage converter.

[0078] Step S3: Suppress the oscillations of the new energy flexible DC interconnection system based on the fundamental modulation voltage of the energy storage converter in the three-phase stationary coordinate system and the oscillation suppression voltage of the energy storage converter in the three-phase stationary coordinate system.

[0079] In some possible implementations, step S1 involves controlling the actual output current of the energy storage converter based on its active power reference value and reactive power reference value to obtain the fundamental modulation voltage of the energy storage converter in a three-phase stationary coordinate system, including: like Figure 3 As shown, the actual three-phase voltage at the grid connection point of the new energy power station. u pcc Phase-locked loop (PLL) control is performed to obtain the synchronous phase θ of the power grid connected to the new energy flexible DC interconnection system.

[0080] Based on the synchronous phase θ of the power grid and the active power reference value P of the energy storage converter ref The reactive power reference value Q of the energy storage converter ref Actual output current value of energy storage converter i abcThe modulated voltage of the output energy storage converter in a two-phase rotating coordinate system (i.e., the d-axis modulated voltage of the energy storage converter in a two-phase rotating coordinate system) v d1 and q-axis modulation voltage v q1 ).

[0081] Based on the synchronous phase θ of the power grid, an inverse Park transform (i.e., dq / abc transform, inverse Park transform) is performed on the modulation voltage of the energy storage converter in the two-phase rotating coordinate system to obtain the fundamental modulation voltage of the energy storage converter in the three-phase stationary coordinate system. v cacbc .

[0082] Furthermore, based on the grid's synchronous phase θ and the active power reference value P of the energy storage converter... ref The reactive power reference value Q of the energy storage converter ref Actual output current value of energy storage converter i abc The modulated voltage of the output energy storage converter in a two-phase rotating coordinate system (i.e., the d-axis modulated voltage of the energy storage converter in a two-phase rotating coordinate system) v d1 and q-axis modulation voltage v q1 ),include: refer to Figure 3 The actual value of the output current of the energy storage converter i abc Performing the Park transformation (also known as the abc / dq transformation) yields the actual d-axis output current of the energy storage converter in a two-phase rotating coordinate system. i d and the actual value of q-axis output current i q .

[0083] Based on the active power reference value P of the energy storage converter ref Actual d-axis output current of the energy storage converter in a two-phase rotating coordinate system i d Calculate the d-axis output voltage of the energy storage converter in a two-phase rotating coordinate system. v d2 According to the reactive power reference value Q of the energy storage converter. ref Actual q-axis output current of the energy storage converter in a two-phase rotating coordinate system i q Calculate the q-axis output voltage of the energy storage converter in a two-phase rotating coordinate system. v q2 .

[0084] Based on the actual value of the d-axis output current of the energy storage converter in a two-phase rotating coordinate system i d Calculate the d-axis decoupling voltage of the energy storage converter in a two-phase rotating coordinate system. v d3 Based on the actual value of the q-axis output current of the energy storage converter in a two-phase rotating coordinate system. i q Calculate the q-axis decoupling voltage of the energy storage converter in a two-phase rotating coordinate system. v q3 .satisfy v d3 =ωL i d , v q3 =ωL i q .in, Indicates the power frequency angular frequency. This indicates the inductance value of the grid-connected inductor of the energy storage converter.

[0085] The d-axis output voltage of the energy storage converter in a two-phase rotating coordinate system v d2 Decoupling voltage of energy storage converter in two-phase rotating coordinate system along the q-axis v q3 The difference is used as the d-axis modulation voltage of the energy storage converter in a two-phase rotating coordinate system. v d1 The q-axis output voltage of the energy storage converter in a two-phase rotating coordinate system. v q2 Decoupling voltage of the energy storage converter along the d-axis in a two-phase rotating coordinate system v d3 Superposition yields the q-axis modulated voltage of the energy storage converter in a two-phase rotating coordinate system. v q1 .

[0086] Optionally, based on the active power reference value P of the energy storage converter ref Actual d-axis output current of the energy storage converter in a two-phase rotating coordinate system i d Calculate the d-axis output voltage of the energy storage converter in a two-phase rotating coordinate system. v d2 ,include: refer to Figure 3 The active power reference value P of the energy storage converter ref Actual active power of the energy storage converter P The difference is used for proportional-integral (PI) control to obtain the d-axis current reference value of the energy storage converter in a two-phase rotating coordinate system. idref .

[0087] The d-axis current reference value of the energy storage converter in a two-phase rotating coordinate system i dref Actual d-axis output current of the energy storage converter in a two-phase rotating coordinate system i d The difference is used for proportional-integral control to obtain the d-axis output voltage of the energy storage converter in a two-phase rotating coordinate system. v d2 .

[0088] Based on the reactive power reference value Q of the energy storage converter ref Actual q-axis output current of the energy storage converter in a two-phase rotating coordinate system i q Calculate the q-axis output voltage of the energy storage converter in a two-phase rotating coordinate system. v q2 ,include: refer to Figure 3 The reactive power reference value Q of the energy storage converter ref Actual reactive power of the energy storage converter Q The difference is used for proportional-integral control to obtain the q-axis current reference value of the energy storage converter in a two-phase rotating coordinate system. i qref .

[0089] The q-axis current reference value of the energy storage converter in a two-phase rotating coordinate system. i qref Actual q-axis output current of the energy storage converter in a two-phase rotating coordinate system i q The difference is used for proportional-integral control to obtain the q-axis output voltage of the energy storage converter in a two-phase rotating coordinate system. v q2 .

[0090] For example, the d-axis decoupling voltage of the energy storage converter in a two-phase rotating coordinate system satisfies ,in, This represents the d-axis decoupling voltage of the energy storage converter in a two-phase rotating coordinate system. This represents the actual d-axis output current of the energy storage converter in a two-phase rotating coordinate system. Indicates the power frequency angular frequency. This indicates the inductance value of the grid-connected inductor of the energy storage converter.

[0091] The q-axis decoupling voltage of the energy storage converter in a two-phase rotating coordinate system satisfies: ,in, This represents the q-axis decoupling voltage of the energy storage converter in a two-phase rotating coordinate system. Actual value of q-axis output current of the energy storage converter in a two-phase rotating coordinate system.

[0092] In some other possible implementations, step S2 calculates the oscillation suppression voltage of the energy storage converter in the three-phase stationary coordinate system based on the actual three-phase voltage value at the grid connection point of the new energy power station and the actual output current value of the energy storage converter, including: Based on the actual three-phase voltage value at the grid connection point of the new energy power station u pcc Determine the reference value of the oscillation suppression current of the energy storage converter in a two-phase stationary coordinate system (i.e., the reference value of the energy storage converter in a two-phase stationary coordinate system). α Shaft oscillation suppression current reference value i h_αref and β-axis oscillation suppression current reference value i h_βref ).

[0093] Based on the actual value of the output current of the energy storage converter i abc And the reference value of the oscillation suppression current of the energy storage converter in the two-phase stationary coordinate system (i.e. i h_αref and i h_βref And determine the oscillation compensation voltage of the energy storage converter in the two-phase stationary coordinate system (i.e., the oscillation compensation voltage of the energy storage converter in the two-phase stationary coordinate system). α Shaft oscillation compensation voltage v h_α and β-axis oscillation compensation voltage v h_β ).

[0094] The oscillation compensation voltage of the energy storage converter in the two-phase stationary coordinate system (i.e.) v h_α and v h_β Perform the inverse Clarke transformation (i.e.) α (β / abc transform, inverse Clark transform) to obtain the oscillation suppression voltage of the energy storage converter in the three-phase stationary coordinate system. v habc .

[0095] Furthermore, based on the actual three-phase voltage values ​​at the grid connection point of the new energy power station... u pcc Determine the reference value of the oscillation suppression current of the energy storage converter in a two-phase stationary coordinate system (i.e., the reference value of the energy storage converter in a two-phase stationary coordinate system). α Shaft oscillation suppression current reference value i h_αref and β-axis oscillation suppression current reference value i h_βref),include: refer to Figure 4 The actual three-phase voltage value at the grid connection point of the new energy power station u pcc Perform the Clarke transformation (i.e., abc / α (β transform, Clark transform) to obtain the actual α-axis voltage value of the grid connection point of the renewable energy power station in a two-phase stationary coordinate system. u pcc_α and actual value of β-axis voltage u pcc_β .

[0096] Set the preset α-axis voltage reference value u h_αref (Can be taken as 0) Actual value of α-axis voltage at the grid connection point of the new energy power station in a two-phase stationary coordinate system. u pcc_α The difference is used for proportional resonance control (PR control) to obtain the reference value of the α-axis oscillation suppression current of the energy storage converter in the two-phase stationary coordinate system. i h_αref And set the preset β-axis voltage reference value. u h_βref (Can be taken as 0) Actual value of β-axis voltage at the grid connection point of the new energy power station in a two-phase stationary coordinate system. u pcc_β The difference is used for proportional resonance control to obtain the reference value of the β-axis oscillation suppression current of the energy storage converter in the two-phase stationary coordinate system. i h_βref .

[0097] Optionally, based on the actual output current value of the energy storage converter. i abc And the reference value of the oscillation suppression current of the energy storage converter in the two-phase stationary coordinate system (i.e. i h_αref and i h_βref And determine the oscillation compensation voltage of the energy storage converter in the two-phase stationary coordinate system (i.e., the oscillation compensation voltage of the energy storage converter in the two-phase stationary coordinate system). α Shaft oscillation compensation voltage v h_α and β-axis oscillation compensation voltage v h_β ),include: refer to Figure 4 The actual value of the output current of the energy storage converter i abc Perform the Clarke transformation (i.e., abc / α (β transform, Clark transform) to obtain the actual α-axis current value of the energy storage converter in a two-phase stationary coordinate system. iα and actual value of β-axis current i β .

[0098] Reference value for α-axis oscillation suppression current of energy storage converter in two-phase stationary coordinate system i h_αref Actual α-axis current of the energy storage converter in a two-phase stationary coordinate system i α The difference is used for proportional resonance control to obtain the α-axis oscillation compensation voltage of the energy storage converter in the two-phase stationary coordinate system. v h_α .

[0099] Reference value for β-axis oscillation suppression current of energy storage converter in two-phase stationary coordinate system i h_βref Actual β-axis current of the energy storage converter in a two-phase stationary coordinate system i β The difference is used for proportional resonance control to obtain the β-axis oscillation compensation voltage of the energy storage converter in the two-phase stationary coordinate system. v h_β .

[0100] In some other possible implementations, step S3 involves suppressing the oscillations occurring in the new energy flexible DC interconnection system based on the fundamental modulation voltage of the energy storage converter in the three-phase stationary coordinate system and the oscillation suppression voltage of the energy storage converter in the three-phase stationary coordinate system, including: refer to Figure 5 The fundamental frequency modulation voltage of the energy storage converter in the three-phase stationary coordinate system v cabc Oscillation suppression voltage of energy storage converter in three-phase stationary coordinate system v habc By superposition, the control voltage of the energy storage converter in the three-phase stationary coordinate system is obtained. v abcref .

[0101] The control voltage of the energy storage converter in the three-phase stationary coordinate system v abcref Modulation (SVPWM modulation) is performed to obtain a control signal, and the energy storage converter is controlled according to the control signal.

[0102] Optionally, the oscillation suppression method provided in this application embodiment may further include: refer to Figure 5 The actual three-phase voltage values ​​collected at the grid connection points of new energy power plants u pccPerform a Fourier transform (DFT) to obtain the voltage amplitude of the new energy power plant's grid connection point at different frequencies (e.g., obtain the voltage amplitude of the new energy power plant's grid connection point at different frequencies). f hx voltage amplitude U hx ).

[0103] If the voltage amplitude at the grid connection point of the new energy power station at different frequencies (e.g.) U hx () greater than the preset voltage threshold U thx It was determined that the new energy flexible DC interconnection system was experiencing oscillations.

[0104] Understandably, if the flexible DC interconnection system for new energy sources experiences oscillations, it can be combined with... v cabc and v habc The control signal is obtained to suppress the oscillation of the new energy flexible DC interconnection system. If the new energy flexible DC interconnection system does not oscillate, it can be directly controlled by... v cabc Modulation (such as SVPWM modulation) is performed to obtain a control signal, which is then used to control the energy storage converter, i.e., to perform fundamental frequency control on the energy storage converter.

[0105] Optionally, before step S1, this application may also collect the actual three-phase voltage values ​​of the grid connection point of the new energy power station according to a preset frequency range (such as 100, 150, ..., 2500Hz) and a preset frequency interval (such as 10Hz or 50Hz).

[0106] Example 2: Based on the same inventive concept, this application also provides an oscillation suppression device for a new energy flexible DC interconnection system. For a related introduction to the new energy flexible DC interconnection system, please refer to the above and... Figure 1 .

[0107] like Figure 6 As shown, the oscillation suppression device 300 may include: Control module 301 is used to control the actual output current of the energy storage converter based on the active power reference value and reactive power reference value of the energy storage converter, so as to obtain the fundamental modulation voltage of the energy storage converter in the three-phase stationary coordinate system. v cacbc .

[0108] Calculation module 302 is used to calculate the oscillation suppression voltage of the energy storage converter in the three-phase stationary coordinate system based on the actual three-phase voltage value at the grid connection point of the new energy power plant and the actual output current value of the energy storage converter. v habc.

[0109] Suppression module 303 is used to suppress the fundamental modulation voltage of the energy storage converter in the three-phase stationary coordinate system. v cacbc Oscillation suppression voltage of energy storage converter in three-phase stationary coordinate system v habc To suppress oscillations in new energy flexible DC interconnection systems.

[0110] In some possible implementations, the control module 301 is specifically used for: like Figure 3 As shown, the actual three-phase voltage at the grid connection point of the new energy power station. u pcc Phase-locked loop (PLL) control is performed to obtain the synchronous phase θ of the power grid connected to the new energy flexible DC interconnection system.

[0111] Based on the synchronous phase θ of the power grid and the active power reference value P of the energy storage converter ref The reactive power reference value Q of the energy storage converter ref Actual output current value of energy storage converter i abc The modulated voltage of the output energy storage converter in a two-phase rotating coordinate system (i.e., the d-axis modulated voltage of the energy storage converter in a two-phase rotating coordinate system) v d1 and q-axis modulation voltage v q1 ).

[0112] Based on the synchronous phase θ of the power grid, an inverse Park transform (i.e., dq / abc transform, inverse Park transform) is performed on the modulation voltage of the energy storage converter in the two-phase rotating coordinate system to obtain the fundamental modulation voltage of the energy storage converter in the three-phase stationary coordinate system. v cacbc .

[0113] Furthermore, the control module 301 is specifically used for: refer to Figure 3 The actual value of the output current of the energy storage converter i abc Performing the Park transformation (also known as the abc / dq transformation) yields the actual d-axis output current of the energy storage converter in a two-phase rotating coordinate system. i d and the actual value of q-axis output current i q .

[0114] Based on the active power reference value P of the energy storage converter ref Actual d-axis output current of the energy storage converter in a two-phase rotating coordinate systemi d Calculate the d-axis output voltage of the energy storage converter in a two-phase rotating coordinate system. v d2 According to the reactive power reference value Q of the energy storage converter. ref Actual q-axis output current of the energy storage converter in a two-phase rotating coordinate system i q Calculate the q-axis output voltage of the energy storage converter in a two-phase rotating coordinate system. v q2 .

[0115] Based on the actual value of the d-axis output current of the energy storage converter in a two-phase rotating coordinate system i d Calculate the d-axis decoupling voltage of the energy storage converter in a two-phase rotating coordinate system. v d3 Based on the actual value of the q-axis output current of the energy storage converter in a two-phase rotating coordinate system. i q Calculate the q-axis decoupling voltage of the energy storage converter in a two-phase rotating coordinate system. v q3 .satisfy v d3 =ωL i d , v q3 =ωL i q .in, Indicates the power frequency angular frequency. This indicates the inductance value of the grid-connected inductor of the energy storage converter.

[0116] The d-axis output voltage of the energy storage converter in a two-phase rotating coordinate system v d2 Decoupling voltage of energy storage converter in two-phase rotating coordinate system along the q-axis v q3 The difference is used as the d-axis modulation voltage of the energy storage converter in a two-phase rotating coordinate system. v d1 The q-axis output voltage of the energy storage converter in a two-phase rotating coordinate system. v q2 Decoupling voltage of the energy storage converter along the d-axis in a two-phase rotating coordinate system v d3 Superposition yields the q-axis modulated voltage of the energy storage converter in a two-phase rotating coordinate system. v q1 .

[0117] Optionally, the control module 301 is specifically used for: refer to Figure 3The active power reference value P of the energy storage converter ref Actual active power of the energy storage converter P The difference is used for proportional-integral (PI) control to obtain the d-axis current reference value of the energy storage converter in a two-phase rotating coordinate system. i dref .

[0118] The d-axis current reference value of the energy storage converter in a two-phase rotating coordinate system i dref Actual d-axis output current of the energy storage converter in a two-phase rotating coordinate system i d The difference is used for proportional-integral control to obtain the d-axis output voltage of the energy storage converter in a two-phase rotating coordinate system. v d2 .

[0119] For example, the control module 301 is specifically used for: refer to Figure 3 The reactive power reference value Q of the energy storage converter ref Actual reactive power of the energy storage converter i q The difference is used for proportional-integral control to obtain the q-axis current reference value of the energy storage converter in a two-phase rotating coordinate system. i qref .

[0120] The q-axis current reference value of the energy storage converter in a two-phase rotating coordinate system. i qref Actual q-axis output current of the energy storage converter in a two-phase rotating coordinate system i q The difference is used for proportional-integral control to obtain the q-axis output voltage of the energy storage converter in a two-phase rotating coordinate system. v q2 .

[0121] The d-axis decoupling voltage of the energy storage converter in a two-phase rotating coordinate system satisfies ,in, This represents the d-axis decoupling voltage of the energy storage converter in a two-phase rotating coordinate system. This represents the actual d-axis output current of the energy storage converter in a two-phase rotating coordinate system. Indicates the power frequency angular frequency. This indicates the inductance value of the grid-connected inductor of the energy storage converter.

[0122] The q-axis decoupling voltage of the energy storage converter in a two-phase rotating coordinate system satisfies: ,in, This represents the q-axis decoupling voltage of the energy storage converter in a two-phase rotating coordinate system. Actual value of q-axis output current of the energy storage converter in a two-phase rotating coordinate system.

[0123] In some other possible implementations, the computing module 302 is specifically used for: Based on the actual three-phase voltage value at the grid connection point of the new energy power station u pcc Determine the reference value of the oscillation suppression current of the energy storage converter in a two-phase stationary coordinate system (i.e., the reference value of the energy storage converter in a two-phase stationary coordinate system). α Shaft oscillation suppression current reference value i h_αref and β-axis oscillation suppression current reference value i h_βref ).

[0124] Based on the actual value of the output current of the energy storage converter i abc And the reference value of the oscillation suppression current of the energy storage converter in the two-phase stationary coordinate system (i.e. i h_αref and i h_βref And determine the oscillation compensation voltage of the energy storage converter in the two-phase stationary coordinate system (i.e., the oscillation compensation voltage of the energy storage converter in the two-phase stationary coordinate system). α Shaft oscillation compensation voltage v h_α and β-axis oscillation compensation voltage v h_β ).

[0125] The oscillation compensation voltage of the energy storage converter in the two-phase stationary coordinate system (i.e.) v h_α and v h_β Perform the inverse Clarke transformation (i.e.) α (β / abc transform, inverse Clark transform) to obtain the oscillation suppression voltage of the energy storage converter in the three-phase stationary coordinate system. v habc .

[0126] Optionally, the calculation module 302 is specifically used for: refer to Figure 4 The actual three-phase voltage value at the grid connection point of the new energy power station u pcc Perform the Clarke transformation (i.e., abc / α (β transform, Clark transform) to obtain the actual α-axis voltage value of the grid connection point of the renewable energy power station in a two-phase stationary coordinate system. u pcc_α and actual value of β-axis voltage upcc_β .

[0127] Set the preset α-axis voltage reference value u h_αref (Can be taken as 0) Actual value of α-axis voltage at the grid connection point of the new energy power station in a two-phase stationary coordinate system. u pcc_α The difference is used for proportional resonance control (PR control) to obtain the reference value of the α-axis oscillation suppression current of the energy storage converter in the two-phase stationary coordinate system. i h_αref And set the preset β-axis voltage reference value. u h_βref (Can be taken as 0) Actual value of β-axis voltage at the grid connection point of the new energy power station in a two-phase stationary coordinate system. u pcc_β The difference is used for proportional resonance control to obtain the reference value of the β-axis oscillation suppression current of the energy storage converter in the two-phase stationary coordinate system. i h_βref .

[0128] For example, the calculation module 302 is specifically used for: refer to Figure 4 The actual value of the output current of the energy storage converter i abc Perform the Clarke transformation (i.e., abc / α (β transform, Clark transform) to obtain the actual α-axis current value of the energy storage converter in a two-phase stationary coordinate system. i α and actual value of β-axis current i β .

[0129] Reference value for α-axis oscillation suppression current of energy storage converter in two-phase stationary coordinate system i h_αref Actual α-axis current of the energy storage converter in a two-phase stationary coordinate system i α The difference is used for proportional resonance control to obtain the α-axis oscillation compensation voltage of the energy storage converter in the two-phase stationary coordinate system. v h_α .

[0130] Reference value for β-axis oscillation suppression current of energy storage converter in two-phase stationary coordinate system i h_βref Actual β-axis current of the energy storage converter in a two-phase stationary coordinate system i β The difference is used for proportional resonance control to obtain the β-axis oscillation compensation voltage of the energy storage converter in the two-phase stationary coordinate system. v h_β .

[0131] In some other possible implementations, the suppression module 303 is specifically used for: refer to Figure 5 The fundamental frequency modulation voltage of the energy storage converter in the three-phase stationary coordinate system v cabc Oscillation suppression voltage of energy storage converter in three-phase stationary coordinate system v habc By superposition, the control voltage of the energy storage converter in the three-phase stationary coordinate system is obtained. v abcref .

[0132] The control voltage of the energy storage converter in the three-phase stationary coordinate system v abcref Modulation (SVPWM modulation) is performed to obtain a control signal, and the energy storage converter is controlled according to the control signal.

[0133] Optionally, the oscillation suppression device further includes a determination module. The determination module is used for: refer to Figure 5 The actual three-phase voltage values ​​collected at the grid connection points of new energy power plants u pcc Perform a Fourier transform (DFT) to obtain the voltage amplitude of the new energy power plant's grid connection point at different frequencies (e.g., obtain the voltage amplitude of the new energy power plant's grid connection point at different frequencies). f hx voltage amplitude U hx ).

[0134] If the voltage amplitude at the grid connection point of the new energy power station at different frequencies (e.g.) U hx () greater than the preset voltage threshold U thx It was determined that the new energy flexible DC interconnection system was experiencing oscillations.

[0135] Understandably, if the flexible DC interconnection system for new energy sources experiences oscillations, it can be combined with... v cabc and v habc The control signal is obtained to suppress the oscillation of the new energy flexible DC interconnection system. If the new energy flexible DC interconnection system does not oscillate, it can be directly controlled by... v cabc Modulation (such as SVPWM modulation) is performed to obtain a control signal, which is then used to control the energy storage converter, i.e., to perform fundamental frequency control on the energy storage converter.

[0136] Optionally, the oscillation suppression device also includes a data acquisition module, which can acquire the actual three-phase voltage values ​​at the grid connection point of the new energy power station according to a preset frequency range (such as 100, 150, ..., 2500Hz) and a preset frequency interval (such as 10Hz or 50Hz).

[0137] Example 3: Based on the same inventive concept, this application also provides a computer device, which includes a processor and a memory. The memory stores a computer program, which includes program instructions. The processor executes the program instructions stored in the computer storage medium. The processor may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. It is the computing and control core of the terminal, and is suitable for implementing one or more instructions. Specifically, it is suitable for loading and executing one or more instructions in the computer storage medium to implement the corresponding method flow or corresponding function, so as to implement the steps of the oscillation suppression method provided in the above embodiments.

[0138] Example 4: Based on the same inventive concept, this application also provides a computer-readable storage medium, specifically a computer-readable storage medium (Memory). A computer-readable storage medium is a memory device in a computer device used to store programs and data. It is understood that the computer-readable storage medium here can include both the built-in storage medium in the computer device and extended storage media supported by the computer device. The computer-readable storage medium provides storage space that stores the terminal's operating system. Furthermore, this storage space also stores one or more instructions suitable for loading and execution by a processor. These instructions can be one or more computer programs (including program code). It should be noted that the computer-readable storage medium here can be high-speed RAM or non-volatile memory, such as at least one disk storage device. The processor can load and execute one or more instructions stored in the computer-readable storage medium to implement the steps of the oscillation suppression method provided in the above embodiments.

[0139] Those skilled in the art will understand that the embodiments of the application can be provided as a method, system, or computer program product. Therefore, the application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the application can take the form of a computer program product implemented on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0140] The application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0141] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0142] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0143] The above are merely examples of the application and are not intended to limit the application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the application shall be included within the scope of the claims of the pending application.

Claims

1. A method for suppressing oscillations in a new energy flexible DC interconnection system, characterized in that, include: The actual output current of the energy storage converter is controlled based on the active power reference value and reactive power reference value of the energy storage converter to obtain the fundamental modulation voltage of the energy storage converter in the three-phase stationary coordinate system. Calculate the oscillation suppression voltage of the energy storage converter in the three-phase stationary coordinate system based on the actual three-phase voltage value of the new energy power station grid connection point and the actual output current value of the energy storage converter. The oscillations occurring in the new energy flexible DC interconnection system are suppressed based on the fundamental modulation voltage of the energy storage converter in the three-phase stationary coordinate system and the oscillation suppression voltage of the energy storage converter in the three-phase stationary coordinate system.

2. The oscillation suppression method according to claim 1, characterized in that, The step of controlling the actual output current of the energy storage converter based on the active power reference value and reactive power reference value of the energy storage converter to obtain the fundamental modulation voltage of the energy storage converter in the three-phase stationary coordinate system includes: Phase-locked loop control is performed on the actual three-phase voltage value at the grid connection point of the new energy power station to obtain the synchronous phase of the power grid connected to the new energy flexible DC interconnection system; Based on the synchronous phase of the power grid, the active power reference value of the energy storage converter, the reactive power reference value of the energy storage converter, and the actual output current value of the energy storage converter, the modulation voltage of the energy storage converter in the two-phase rotating coordinate system is output. Based on the synchronous phase of the power grid, the modulation voltage of the energy storage converter in the two-phase rotating coordinate system is subjected to an inverse Park transform to obtain the fundamental modulation voltage of the energy storage converter in the three-phase stationary coordinate system.

3. The oscillation suppression method according to claim 2, characterized in that, The step of outputting the modulation voltage of the energy storage converter in a two-phase rotating coordinate system based on the synchronous phase of the power grid, the active power reference value of the energy storage converter, the reactive power reference value of the energy storage converter, and the actual output current value of the energy storage converter includes: The actual output current value of the energy storage converter is subjected to Park transformation to obtain the actual d-axis output current value and q-axis output current value of the energy storage converter in a two-phase rotating coordinate system. The d-axis output voltage of the energy storage converter in the two-phase rotating coordinate system is calculated based on the active power reference value of the energy storage converter and the actual value of the d-axis output current of the energy storage converter in the two-phase rotating coordinate system; the q-axis output voltage of the energy storage converter in the two-phase rotating coordinate system is calculated based on the reactive power reference value of the energy storage converter and the actual value of the q-axis output current of the energy storage converter in the two-phase rotating coordinate system. Calculate the d-axis decoupling voltage of the energy storage converter in the two-phase rotating coordinate system based on the actual value of the d-axis output current of the energy storage converter in the two-phase rotating coordinate system; calculate the q-axis decoupling voltage of the energy storage converter in the two-phase rotating coordinate system based on the actual value of the q-axis output current of the energy storage converter in the two-phase rotating coordinate system. The difference between the d-axis output voltage of the energy storage converter in the two-phase rotating coordinate system and the q-axis decoupling voltage of the energy storage converter in the two-phase rotating coordinate system is taken as the d-axis modulation voltage of the energy storage converter in the two-phase rotating coordinate system; the q-axis output voltage of the energy storage converter in the two-phase rotating coordinate system is superimposed with the d-axis decoupling voltage of the energy storage converter in the two-phase rotating coordinate system to obtain the q-axis modulation voltage of the energy storage converter in the two-phase rotating coordinate system.

4. The oscillation suppression method according to claim 3, characterized in that, The calculation of the d-axis output voltage of the energy storage converter in the two-phase rotating coordinate system based on the active power reference value of the energy storage converter and the actual value of the d-axis output current of the energy storage converter in the two-phase rotating coordinate system includes: The difference between the active power reference value and the actual active power value of the energy storage converter is used for proportional-integral control to obtain the d-axis current reference value of the energy storage converter in a two-phase rotating coordinate system. The difference between the reference value of the d-axis current of the energy storage converter in the two-phase rotating coordinate system and the actual value of the d-axis output current of the energy storage converter in the two-phase rotating coordinate system is used for proportional-integral control to obtain the d-axis output voltage of the energy storage converter in the two-phase rotating coordinate system.

5. The oscillation suppression method according to claim 3, characterized in that, The calculation of the q-axis output voltage of the energy storage converter in the two-phase rotating coordinate system based on the reactive power reference value of the energy storage converter and the actual value of the q-axis output current of the energy storage converter in the two-phase rotating coordinate system includes: The difference between the reactive power reference value and the actual reactive power value of the energy storage converter is subjected to proportional-integral control to obtain the q-axis current reference value of the energy storage converter in a two-phase rotating coordinate system. The difference between the reference value of the q-axis current of the energy storage converter in the two-phase rotating coordinate system and the actual value of the q-axis output current of the energy storage converter in the two-phase rotating coordinate system is used for proportional-integral control to obtain the q-axis output voltage of the energy storage converter in the two-phase rotating coordinate system.

6. The oscillation suppression method according to claim 3, characterized in that, The d-axis decoupling voltage of the energy storage converter in a two-phase rotating coordinate system satisfies ,in, This represents the d-axis decoupling voltage of the energy storage converter in a two-phase rotating coordinate system. This represents the actual d-axis output current value of the energy storage converter in a two-phase rotating coordinate system. Indicates the power frequency angular frequency. This represents the inductance value of the grid-connected inductor of the energy storage converter; The q-axis decoupling voltage of the energy storage converter in a two-phase rotating coordinate system satisfies: ,in, This represents the q-axis decoupling voltage of the energy storage converter in a two-phase rotating coordinate system. The actual value of the q-axis output current of the energy storage converter in a two-phase rotating coordinate system.

7. The oscillation suppression method according to claim 1, characterized in that, The calculation of the oscillation suppression voltage of the energy storage converter in the three-phase stationary coordinate system based on the actual three-phase voltage value of the new energy power station grid connection point and the actual output current value of the energy storage converter includes: The reference value of the oscillation suppression current of the energy storage converter in the two-phase stationary coordinate system is determined based on the actual value of the three-phase voltage at the grid connection point of the new energy power station. The oscillation compensation voltage of the energy storage converter in the two-phase stationary coordinate system is determined based on the actual output current value of the energy storage converter and the oscillation suppression current reference value of the energy storage converter in the two-phase stationary coordinate system. The oscillation compensation voltage of the energy storage converter in the two-phase stationary coordinate system is subjected to an inverse Clarke transformation to obtain the oscillation suppression voltage of the energy storage converter in the three-phase stationary coordinate system.

8. The oscillation suppression method according to claim 7, characterized in that, The step of determining the oscillation suppression current reference value of the energy storage converter in a two-phase stationary coordinate system based on the actual three-phase voltage value of the new energy power station's grid connection point includes: The actual three-phase voltage values ​​at the grid connection point of the new energy power station are subjected to Clark transformation to obtain the actual α-axis voltage values ​​and β-axis voltage values ​​at the grid connection point of the new energy power station in a two-phase stationary coordinate system. The difference between the preset α-axis voltage reference value and the actual α-axis voltage value of the new energy power station grid connection point in the two-phase stationary coordinate system is used for proportional resonance control to obtain the α-axis oscillation suppression current reference value of the energy storage converter in the two-phase stationary coordinate system; and the difference between the preset β-axis voltage reference value and the actual β-axis voltage value of the new energy power station grid connection point in the two-phase stationary coordinate system is used for proportional resonance control to obtain the β-axis oscillation suppression current reference value of the energy storage converter in the two-phase stationary coordinate system.

9. The oscillation suppression method according to claim 8, characterized in that, The step of determining the oscillation compensation voltage of the energy storage converter in the two-phase stationary coordinate system based on the actual output current value of the energy storage converter and the oscillation suppression current reference value of the energy storage converter in the two-phase stationary coordinate system includes: The actual output current value of the energy storage converter is subjected to Clark transformation to obtain the actual α-axis current value and β-axis current value of the energy storage converter in the two-phase stationary coordinate system. The difference between the reference value of the α-axis oscillation suppression current of the energy storage converter in the two-phase stationary coordinate system and the actual value of the α-axis current of the energy storage converter in the two-phase stationary coordinate system is used for proportional resonance control to obtain the α-axis oscillation compensation voltage of the energy storage converter in the two-phase stationary coordinate system. The difference between the reference value of the β-axis oscillation suppression current of the energy storage converter in the two-phase stationary coordinate system and the actual value of the β-axis current of the energy storage converter in the two-phase stationary coordinate system is used for proportional resonance control to obtain the β-axis oscillation compensation voltage of the energy storage converter in the two-phase stationary coordinate system.

10. The oscillation suppression method according to claim 1, characterized in that, The method of suppressing oscillations in the new energy flexible DC interconnection system based on the fundamental modulation voltage of the energy storage converter in the three-phase stationary coordinate system and the oscillation suppression voltage of the energy storage converter in the three-phase stationary coordinate system includes: The fundamental modulation voltage of the energy storage converter in the three-phase stationary coordinate system and the oscillation suppression voltage of the energy storage converter in the three-phase stationary coordinate system are superimposed to obtain the control voltage of the energy storage converter in the three-phase stationary coordinate system. The control voltage of the energy storage converter in the three-phase stationary coordinate system is modulated to obtain a control signal, and the energy storage converter is controlled according to the control signal.

11. The oscillation suppression method according to claim 1, characterized in that, The oscillation suppression method further includes: Fourier transform is performed on the actual three-phase voltage values ​​of the new energy power station grid connection point to obtain the voltage amplitude of the new energy power station grid connection point at different frequencies. If the voltage amplitude at the grid connection point of the new energy power station is greater than a preset voltage threshold at different frequencies, it is determined that the new energy flexible DC interconnection system is oscillating.

12. An oscillation suppression device for a new energy flexible DC interconnection system, characterized in that, include: The control module is used to control the actual output current of the energy storage converter based on the active power reference value and reactive power reference value of the energy storage converter, so as to obtain the fundamental modulation voltage of the energy storage converter in the three-phase stationary coordinate system. The calculation module is used to calculate the oscillation suppression voltage of the energy storage converter in the three-phase stationary coordinate system based on the actual value of the three-phase voltage at the grid connection point of the new energy power station and the actual value of the output current of the energy storage converter. The suppression module is used to suppress the oscillations occurring in the new energy flexible DC interconnection system based on the fundamental modulation voltage of the energy storage converter in the three-phase stationary coordinate system and the oscillation suppression voltage of the energy storage converter in the three-phase stationary coordinate system.

13. The oscillation suppression device according to claim 12, characterized in that, The control module is specifically used for: Phase-locked loop control is performed on the actual three-phase voltage value at the grid connection point of the new energy power station to obtain the synchronous phase of the power grid connected to the new energy flexible DC interconnection system; Based on the synchronous phase of the power grid, the active power reference value of the energy storage converter, the reactive power reference value of the energy storage converter, and the actual output current value of the energy storage converter, the modulation voltage of the energy storage converter in the two-phase rotating coordinate system is output. Based on the synchronous phase of the power grid, the modulation voltage of the energy storage converter in the two-phase rotating coordinate system is subjected to an inverse Park transform to obtain the fundamental modulation voltage of the energy storage converter in the three-phase stationary coordinate system.

14. The oscillation suppression device according to claim 13, characterized in that, The control module is specifically used for: The actual output current value of the energy storage converter is subjected to Park transformation to obtain the actual d-axis output current value and q-axis output current value of the energy storage converter in a two-phase rotating coordinate system. The d-axis output voltage of the energy storage converter in the two-phase rotating coordinate system is calculated based on the active power reference value of the energy storage converter and the actual value of the d-axis output current of the energy storage converter in the two-phase rotating coordinate system; the q-axis output voltage of the energy storage converter in the two-phase rotating coordinate system is calculated based on the reactive power reference value of the energy storage converter and the actual value of the q-axis output current of the energy storage converter in the two-phase rotating coordinate system. Calculate the d-axis decoupling voltage of the energy storage converter in the two-phase rotating coordinate system based on the actual value of the d-axis output current of the energy storage converter in the two-phase rotating coordinate system; calculate the q-axis decoupling voltage of the energy storage converter in the two-phase rotating coordinate system based on the actual value of the q-axis output current of the energy storage converter in the two-phase rotating coordinate system. The difference between the d-axis output voltage of the energy storage converter in the two-phase rotating coordinate system and the q-axis decoupling voltage of the energy storage converter in the two-phase rotating coordinate system is taken as the d-axis modulation voltage of the energy storage converter in the two-phase rotating coordinate system; the q-axis output voltage of the energy storage converter in the two-phase rotating coordinate system is superimposed with the d-axis decoupling voltage of the energy storage converter in the two-phase rotating coordinate system to obtain the q-axis modulation voltage of the energy storage converter in the two-phase rotating coordinate system.

15. The oscillation suppression device according to claim 14, characterized in that, The control module is specifically used for: The difference between the active power reference value and the actual active power value of the energy storage converter is used for proportional-integral control to obtain the d-axis current reference value of the energy storage converter in a two-phase rotating coordinate system. The difference between the reference value of the d-axis current of the energy storage converter in the two-phase rotating coordinate system and the actual value of the d-axis output current of the energy storage converter in the two-phase rotating coordinate system is used for proportional-integral control to obtain the d-axis output voltage of the energy storage converter in the two-phase rotating coordinate system.

16. The oscillation suppression device according to claim 14, characterized in that, The control module is specifically used for: The difference between the reactive power reference value and the actual reactive power value of the energy storage converter is subjected to proportional-integral control to obtain the q-axis current reference value of the energy storage converter in a two-phase rotating coordinate system. The difference between the reference value of the q-axis current of the energy storage converter in the two-phase rotating coordinate system and the actual value of the q-axis output current of the energy storage converter in the two-phase rotating coordinate system is used for proportional-integral control to obtain the q-axis output voltage of the energy storage converter in the two-phase rotating coordinate system.

17. The oscillation suppression device according to claim 14, characterized in that, The d-axis decoupling voltage of the energy storage converter in a two-phase rotating coordinate system satisfies ,in, This represents the d-axis decoupling voltage of the energy storage converter in a two-phase rotating coordinate system. This represents the actual d-axis output current value of the energy storage converter in a two-phase rotating coordinate system. Indicates the power frequency angular frequency. This represents the inductance value of the grid-connected inductor of the energy storage converter; The q-axis decoupling voltage of the energy storage converter in a two-phase rotating coordinate system satisfies: ,in, This represents the q-axis decoupling voltage of the energy storage converter in a two-phase rotating coordinate system. The actual value of the q-axis output current of the energy storage converter in a two-phase rotating coordinate system.

18. The oscillation suppression device according to claim 12, characterized in that, The calculation module is specifically used for: The reference value of the oscillation suppression current of the energy storage converter in the two-phase stationary coordinate system is determined based on the actual value of the three-phase voltage at the grid connection point of the new energy power station. The oscillation compensation voltage of the energy storage converter in the two-phase stationary coordinate system is determined based on the actual output current value of the energy storage converter and the oscillation suppression current reference value of the energy storage converter in the two-phase stationary coordinate system. The oscillation compensation voltage of the energy storage converter in the two-phase stationary coordinate system is subjected to an inverse Clarke transformation to obtain the oscillation suppression voltage of the energy storage converter in the three-phase stationary coordinate system.

19. The oscillation suppression device according to claim 18, characterized in that, The calculation module is specifically used for: The actual three-phase voltage values ​​at the grid connection point of the new energy power station are subjected to Clark transformation to obtain the actual α-axis voltage values ​​and β-axis voltage values ​​at the grid connection point of the new energy power station in a two-phase stationary coordinate system. The difference between the preset α-axis voltage reference value and the actual α-axis voltage value of the grid connection point of the new energy power station in the two-phase stationary coordinate system is used for proportional resonance control to obtain the α-axis oscillation suppression current reference value of the energy storage converter in the two-phase stationary coordinate system. The difference between the preset β-axis voltage reference value and the actual β-axis voltage value of the new energy power station grid connection point in the two-phase stationary coordinate system is used for proportional resonance control to obtain the β-axis oscillation suppression current reference value of the energy storage converter in the two-phase stationary coordinate system.

20. The oscillation suppression device according to claim 19, characterized in that, The calculation module is specifically used for: The actual output current value of the energy storage converter is subjected to Clark transformation to obtain the actual α-axis current value and β-axis current value of the energy storage converter in the two-phase stationary coordinate system. The difference between the reference value of the α-axis oscillation suppression current of the energy storage converter in the two-phase stationary coordinate system and the actual value of the α-axis current of the energy storage converter in the two-phase stationary coordinate system is used for proportional resonance control to obtain the α-axis oscillation compensation voltage of the energy storage converter in the two-phase stationary coordinate system. The difference between the reference value of the β-axis oscillation suppression current of the energy storage converter in the two-phase stationary coordinate system and the actual value of the β-axis current of the energy storage converter in the two-phase stationary coordinate system is used for proportional resonance control to obtain the β-axis oscillation compensation voltage of the energy storage converter in the two-phase stationary coordinate system.

21. The oscillation suppression device according to claim 12, characterized in that, The suppression module is specifically used for: The fundamental modulation voltage of the energy storage converter in the three-phase stationary coordinate system and the oscillation suppression voltage of the energy storage converter in the three-phase stationary coordinate system are superimposed to obtain the control voltage of the energy storage converter in the three-phase stationary coordinate system. The control voltage of the energy storage converter in the three-phase stationary coordinate system is modulated to obtain a control signal, and the energy storage converter is controlled according to the control signal.

22. The oscillation suppression device according to claim 12, characterized in that, The oscillation suppression device further includes a determining module; the determining module is used for: Fourier transform is performed on the actual three-phase voltage values ​​of the new energy power station grid connection point to obtain the voltage amplitude of the new energy power station grid connection point at different frequencies. If the voltage amplitude at the grid connection point of the new energy power station is greater than a preset voltage threshold at different frequencies, it is determined that the new energy flexible DC interconnection system is oscillating.

23. A computer device, characterized in that, include: One or more processors; The processor is used to store one or more programs; When the one or more programs are executed by the one or more processors, the oscillation suppression method as described in any one of claims 1 to 12 is implemented.

24. A computer-readable storage medium, characterized in that, It contains a computer program, which, when executed, implements the oscillation suppression method as described in any one of claims 1 to 12.

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