Power generation system, new energy power generation equipment and transient state control method of new energy power generation equipment

Abstract

The invention provides a power generation system, new energy power generation equipment and a transient state control method of the new energy power generation equipment. According to the limited power of the power grid in the power system, the amplitude of the set value of the generated power of the new energy power generation equipment in the steady-state control method is limited, so that the set value of the generated power is smaller than or equal to the limited power, and the new energy power generation equipment can normally transmit power to the power grid; therefore, the power system in the transient state recovers to the steady state. Due to the fact that the steady-state control method achieves stability of the voltage of the access point under the condition that the power system is in the steady state, stability of the voltage of the access point is achieved under the condition that the power system is in the transient state, and active support of the new energy power generation equipment for the power grid is achieved. And as the steady-state control method can know that the new energy power generation equipment is the network construction type new energy power generation equipment, the active support of the network construction type new energy power generation equipment to the power grid is realized under the condition that the power system is in the steady state.

Description

Technical Field

[0001] The present invention relates to the field of power generation control technology, and in particular to a power generation system, a new energy power generation equipment and a transient control method thereof. Background Art

[0002] The penetration rate of wind and solar power and other renewable energy generation in the power system continues to increase. Due to the great changes in the proportion of renewable energy generation and synchronous generator generation, the power system as a whole presents a "weak support" characteristic, that is, the support inertia of the power system is insufficient and the stability margin is reduced, which poses a challenge to the stability of the power system and also restricts the rapid growth of renewable energy generation.

[0003] At present, grid-connected new energy power generation equipment can provide active support for the frequency and voltage of the power grid when the power system is in a steady state, that is, when the power generation power of the grid-connected new energy power generation equipment is not limited by the transmission line, that is, when its power generation power is not greater than the transmittable power. When the power system is in a transient state, that is, when the power generation power of the grid-connected new energy power generation equipment is not equal to the transmittable power in the connected power system, most studies still recommend switching the grid-connected wind power equipment to the current control mode. However, the switching of this control mode makes the grid-connected new energy power generation equipment lose its ability to support the power grid, which may lead to control instability and fault crossing failure, and may further trigger chain failures in the power system, that is, cause the scope of the fault to expand.

[0004] Therefore, how to realize the active support of grid-building new energy power generation equipment to the power grid when the power system is in a transient state is a technical problem that needs to be solved urgently. Summary of the invention

[0005] In view of this, the present invention provides a power generation system, a new energy power generation equipment and a transient control method thereof, so as to realize the active support of the grid by the grid-building new energy power generation equipment when the power system is in a transient state.

[0006] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0007] The first aspect of the present application provides a transient control method for a new energy power generation equipment, comprising:

[0008] When the power system where the new energy power generation equipment is located is in a transient state, the set value of the power generation power of the new energy power generation equipment in the steady-state control method of the new energy power generation equipment is limited according to the limited power of the power grid in the power system; the steady-state control method is a control method for achieving a stable voltage at the access point of the new energy power generation equipment when the power system is in a steady state;

[0009] According to the steady-state control method, the new energy power generation equipment is controlled.

[0010] Optionally, before controlling the new energy power generation equipment according to the steady-state control method, the method further includes:

[0011] When the power system is in a transient state, the adjustment method for the set value of the direct-axis current of the access point and the adjustment method for the set value of the quadrature-axis current of the access point in the steady-state control method are replaced with proportional adjustment.

[0012] Optionally, the steady-state control method comprises:

[0013] According to the deviation between the set value and the feedback value of the generated power, the phase of the voltage at the access point is adjusted;

[0014] According to the set value of the direct-axis voltage of the access point, the set value of the quadrature-axis voltage of the access point, and the phase of the voltage of the access point, the power converter in the new energy power generation equipment is controlled to perform power conversion.

[0015] Optionally, controlling a power converter in the new energy power generation equipment to perform power conversion according to a set value of the direct-axis voltage of the access point, a set value of the quadrature-axis voltage of the access point, and a phase of the voltage of the access point includes:

[0016] adjusting a set value of the effective value of the voltage at the access point according to a deviation of the effective value of the voltage at the access point;

[0017] Adjusting the set value of the direct-axis current of the access point according to the deviation between the set value of the direct-axis voltage of the access point and the adjustment value of the set value of the effective value of the voltage of the access point;

[0018] According to the deviation of the quadrature axis voltage of the access point, the set value of the quadrature axis current of the access point is adjusted; the set value of the quadrature axis voltage of the access point is equal to zero;

[0019] The power converter is controlled to perform power conversion according to the deviation between the set value and the feedback value of the direct-axis current at the access point, the deviation between the set value and the feedback value of the quadrature-axis current at the access point, and the phase of the voltage at the access point.

[0020] Optionally, before adjusting the set value of the direct-axis current of the access point according to the deviation between the set value of the direct-axis voltage of the access point and the adjustment value of the set value of the effective value of the voltage of the access point, the method further includes:

[0021] According to the reactive power deviation of the access point, the set value of the effective voltage value of the access point is adjusted.

[0022] Optionally, the adjustment method for adjusting the set value of the effective value of the voltage of the access point according to the deviation of the effective value of the voltage of the access point is proportional adjustment.

[0023] Optionally, controlling a power converter in the new energy power generation equipment to perform power conversion according to a set value of the direct-axis voltage of the access point, a set value of the quadrature-axis voltage of the access point, and a phase of the voltage of the access point includes:

[0024] adjusting a set value of a direct-axis current of the access point according to a deviation of a direct-axis voltage of the access point;

[0025] According to the deviation of the quadrature-axis voltage of the access point, adjusting the set value of the quadrature-axis current of the access point;

[0026] The power converter is controlled to perform power conversion according to the deviation between the set value and the feedback value of the direct-axis current at the access point, the deviation between the set value and the feedback value of the quadrature-axis current at the access point, and the phase of the voltage at the access point.

[0027] Optionally, also include:

[0028] When the power system is in a transient state, the set value of the power generation in the steady-state control method is limited according to the current limit of the new energy power generation equipment.

[0029] The second aspect of the present application provides a new energy power generation equipment, including: a new energy power generation device, a power converter and a controller; wherein:

[0030] The AC side of the power converter serves as an access point for the new energy power generation equipment;

[0031] The other side of the power converter is connected to the new energy power generation device;

[0032] The new energy power generation device and the power converter are both controlled by the controller, and the controller is used to execute the transient control method of the new energy power generation equipment as described in any one of the first aspects of the present application.

[0033] The third aspect of the present application provides a power generation system, comprising: a transformer and at least one new energy power generation equipment as described in any one of the second aspects of the present application; wherein:

[0034] Each access point of the new energy power generation equipment is connected to the first side of the transformer, and the second side of the transformer is connected to the power grid in the power system.

[0035] It can be seen from the above technical solution that the present invention provides a transient control method for a new energy power generation equipment. Since the set value of the power generation power of the new energy power generation equipment in the steady-state control method of the new energy power generation equipment is limited according to the limited power of the power grid in the power system, the set value of the power generation power is less than or equal to the limited power of the power grid, so the new energy power generation equipment can normally transmit power to the power grid, thereby controlling the new energy power generation equipment according to the steady-state control method, and the power system in a transient state can be restored to a steady state. In addition, since the steady-state control method of the new energy power generation equipment realizes the stability of the voltage of the above access point when the power system where the new energy power generation equipment is located is in a steady state, the present application realizes the stability of the voltage of the above access point when the power system is in a transient state, that is, the active support of the new energy power generation equipment to the power grid is realized. In addition, since the above steady-state control method can realize the stability of the voltage of the access point when the power system is in a steady state, the new energy power generation equipment is a grid-forming new energy power generation equipment, so the present application realizes the active support of the grid by the grid-forming new energy power generation equipment when the power system is in a steady state. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0037] Figure 1 and Figure 2 Schematic diagrams of two implementation methods of the transient control method of the new energy power generation equipment provided in the embodiments of the present application;

[0038] Figure 3-Figure 6 Schematic diagrams of the flow of four specific implementations of the above-mentioned steady-state control method provided in the embodiments of the present application;

[0039] Figure 7 A flow chart of another implementation of a transient control method for a new energy power generation equipment provided in an embodiment of the present application;

[0040] Figure 8 and Fig. 9 They are control block diagrams corresponding to two implementation modes of the transient control method of the new energy power generation equipment provided in the embodiments of the present application;

[0041] Fig.10 A schematic diagram of the structure of a new energy power generation equipment provided in an embodiment of the present application;

[0042] Fig.11A schematic diagram of the structure of a power generation system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0043] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0044] In this application, relational terms such as first and second, etc. are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the statement "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0045] In order to realize the active support of the grid-building new energy power generation equipment to the grid when the power system is in a transient state, another embodiment of the present application provides a transient control method for the new energy power generation equipment, the specific process of which is shown in the figure, and specifically includes the following steps:

[0046] S110. When the power system where the new energy power generation equipment is located is in a transient state, the set value of the power generation power of the new energy power generation equipment in the steady-state control method of the new energy power generation equipment is limited according to the limited power of the power grid in the above power system.

[0047] The limited power of the power grid in the above power system refers to: the maximum power that the power grid can withstand.

[0048] In a specific example, the power limit of the power grid is determined according to the voltage at the access point of the new energy power generation equipment and the impedance of the transformer.

[0049] The access point of a new energy power generation equipment refers to the location where the new energy power generation equipment is connected to the power grid. Since the new energy power generation equipment is usually connected to the power grid through a transformer, the access point of a new energy power generation equipment usually refers to the connection point between the new energy power generation equipment and the transformer.

[0050] The above is only one way to obtain the limited power of the power grid. In practical applications, including but not limited to this, no specific limitation is made here. It can be determined according to the specific situation and is within the protection scope of this application.

[0051] The above-mentioned steady-state control method is a control method for achieving the stability of the voltage at the access point when the above-mentioned power system is in a steady state. Since the above-mentioned steady-state control method can achieve the stability of the voltage at the access point when the power system is in a steady state, the new energy power generation equipment is a grid-building new energy power generation equipment. As for the specific process of the above-mentioned steady-state control method, it will be described in detail in the following embodiments and will not be repeated here.

[0052] The above-mentioned power generation capacity specifically refers to: the power generation capacity of the new energy power generation device in the new energy power generation equipment.

[0053] S120. Control the new energy power generation equipment according to the above-mentioned steady-state control method.

[0054] Since the set value of the power generation power of the new energy power generation equipment is limited in the steady-state control method of the new energy power generation equipment according to the power limit of the power grid in the power system, the set value of the power generation power is less than or equal to the power limit of the power grid, so the new energy power generation equipment can transmit power to the power grid normally, so that the new energy power generation equipment is controlled according to the steady-state control method, and the power system in a transient state can be restored to a steady state. In addition, since the steady-state control method of the new energy power generation equipment realizes the stability of the voltage of the above-mentioned access point when the power system where the new energy power generation equipment is located is in a steady state, the present application realizes the stability of the voltage of the above-mentioned access point when the power system is in a transient state, that is, the active support of the new energy power generation equipment to the power grid is realized. In addition, since the steady-state control method can realize the stability of the voltage of the access point when the power system is in a steady state, the new energy power generation equipment is a grid-building type new energy power generation equipment, so the present application realizes the active support of the grid by the grid-building type new energy power generation equipment when the power system is in a steady state.

[0055] Another embodiment of the present application provides another specific implementation method of the transient control method of the new energy power generation equipment, and its specific process can be found in Figure 2 ( Figure 2 Only step S210 after step S110 is taken as an example. Figure 1 This embodiment further includes the following steps before step S120 in the above embodiment:

[0056] S210. When the power system is in a transient state, the adjustment method for the set value of the direct-axis current of the access point and the adjustment method for the set value of the quadrature-axis current of the access point in the steady-state control method are replaced with proportional adjustment.

[0057] The direct axis current of the access point refers to the component of the current of the access point on the direct axis. Similarly, the quadrature axis current of the access point refers to the component of the current of the access point on the quadrature axis. Usually, the current of the access point can be obtained by performing a dq transformation on the current of the access point. As for the dq transformation, it is already a very mature technology in the prior art and will not be described in detail here.

[0058] Typically, in the above-mentioned steady-state control method, the set value of the direct-axis current of the above-mentioned access point and the set value of the quadrature-axis current of the above-mentioned access point are adjusted. As for how to adjust the set value of the direct-axis current of the above-mentioned access point and the set value of the quadrature-axis current of the above-mentioned access point, please refer to the description of the specific process of the above-mentioned steady-state control method in the following embodiment, which will not be repeated here.

[0059] Typically, in the above-mentioned steady-state control method, in order to improve the control accuracy of the above-mentioned steady-state control method, the adjustment method for the set value of the direct-axis current of the above-mentioned access point and the adjustment method for the set value of the quadrature-axis current of the above-mentioned access point both include at least one of proportional adjustment, integral adjustment, and differential adjustment, and both cannot include only proportional adjustment.

[0060] In practical applications, step S210 can be executed before step S110, or after step S110, or even at the same time as step S110. No specific limitation is made here and it can be determined according to the specific situation. All of them are within the scope of protection of this application.

[0061] In this embodiment, since the response speed of proportional regulation is faster than that of integral regulation and differential regulation, the adjustment method of the set value of the direct-axis current of the access point and the adjustment method of the set value of the quadrature-axis current of the access point in the steady-state control method are replaced with proportional regulation, so that the response speed of the steady-state control method is accelerated, and the steady-state control method is more suitable for the situation where the power grid is in a transient state. Therefore, when the power system is in a transient state, the voltage of the access point can be made more stable, thereby improving the control accuracy of the transient control method.

[0062] Another embodiment of the present application provides a specific implementation of the above-mentioned steady-state control method. The specific process can be found in Figure 3 ( Figure 3 Only in Figure 2 The specific steps include:

[0063] S310: adjusting the phase of the voltage at the access point according to the deviation between the set value and the feedback value of the generated power.

[0064] The above-mentioned power generation setting value is the maximum output power of the above-mentioned new energy power generation device. Taking the above-mentioned new energy power generation device as a wind turbine as an example, the above-mentioned power generation setting value is calculated by the wind turbine main control system according to the wind conditions and the impeller speed. In addition, the above-mentioned power generation setting value will be converted into an electromagnetic torque instruction and sent to the power converter in the new energy power generation equipment.

[0065] The feedback value of the power generation is the actual value of the power generation of the new energy power generation device obtained by sampling. As for how to sample the power generation of the new energy power generation device, it is already very mature in the prior art and will not be described in detail here.

[0066] Typically, the phase of the voltage at the access point is equal to the phase of the output voltage of the new energy power generation device in the new energy power generation equipment.

[0067] It should be noted that how to adjust the phase of the voltage at the access point according to the deviation between the set value and the feedback value of the generated power is already very mature in the prior art and will not be described in detail here.

[0068] S320, controlling a power converter in the new energy power generation equipment to perform power conversion according to the set value of the direct-axis voltage of the access point, the set value of the quadrature-axis voltage of the access point, and the phase of the voltage of the access point.

[0069] The direct-axis voltage of the access point refers to the component of the voltage of the access point on the direct axis. Similarly, the quadrature-axis voltage of the access point refers to the component of the voltage of the access point on the quadrature axis. Usually, the voltage of the access point can be obtained by performing a dq transformation on the voltage of the access point. As for the dq transformation, it is already a very mature technology in the prior art and will not be described in detail here.

[0070] The setting value of the direct-axis voltage of the above access point is set according to the actual control requirements, and is not specifically limited here. The setting value of the quadrature-axis voltage of the above access point is set according to the actual control requirements, and is not specifically limited here.

[0071] In this embodiment, since the power converter in the new energy power generation equipment is controlled to perform power conversion according to the set value of the direct-axis voltage of the above-mentioned access point, the set value of the quadrature-axis voltage of the above-mentioned access point, and the phase of the voltage of the above-mentioned access point, when the new energy power generation equipment is stable, the direct-axis voltage of the above-mentioned access point is stable, and the quadrature-axis voltage of the above-mentioned access point is stable, so that the voltage of the above-mentioned access point can be stabilized when the above-mentioned power system is in a steady state.

[0072] Another embodiment of the present application provides a specific implementation of step S320. The specific process can be found in Figure 4 ( Figure 4 Only in Figure 3 The specific steps include:

[0073] S410 , adjusting a set value of the direct-axis current of the access point according to a deviation of the direct-axis voltage of the access point.

[0074] The deviation of the direct-axis voltage of the access point is equal to the set value of the direct-axis voltage of the access point minus the feedback value of the direct-axis voltage of the access point. The feedback value of the direct-axis voltage of the access point is the component of the actual voltage of the access point obtained by sampling on the direct axis. As for how to sample the voltage of the access point, it is already very mature in the prior art and will not be described in detail here.

[0075] It should be noted that the direct-axis voltage of the access point and the direct-axis current of the access point have been described in detail in the above embodiments and will not be described again here.

[0076] S420: Adjust the set value of the quadrature-axis current of the access point according to the deviation of the quadrature-axis voltage of the access point.

[0077] The deviation of the quadrature axis voltage of the access point is equal to the set value of the quadrature axis voltage of the access point minus the feedback value of the quadrature axis voltage of the access point. The feedback value of the quadrature axis voltage of the access point is the component of the actual voltage of the access point obtained by sampling on the quadrature axis. As for how to sample the voltage of the access point, it is already very mature in the prior art and will not be described in detail here.

[0078] It should be noted that the quadrature-axis voltage of the access point and the quadrature-axis current of the access point have been described in detail in the above embodiments and will not be described again here.

[0079] S430, controlling the power converter to perform power conversion according to the deviation between the set value and the feedback value of the direct-axis current at the access point, the deviation between the set value and the feedback value of the quadrature-axis current at the access point, and the phase of the voltage at the access point.

[0080] The setting value of the direct axis current of the above access point is set according to the actual control requirements, and is not specifically limited here. The setting value of the quadrature axis current of the above access point is set according to the actual control requirements, and is not specifically limited here.

[0081] The feedback value of the direct-axis current of the access point is the component of the actual current of the access point on the direct axis obtained by sampling. The feedback value of the quadrature-axis current of the access point is the component of the actual current of the access point on the quadrature axis obtained by sampling. As for how to sample the current of the access point, it is already very mature in the prior art and will not be described in detail here.

[0082] It should be noted that the direct-axis current of the access point, the quadrature-axis current of the access point, the set value and feedback value of the direct-axis current of the access point, the set value and feedback value of the quadrature-axis current of the access point, and the phase of the voltage of the access point have been described in detail in the above embodiments and will not be repeated here. In addition, how to control the power converter to perform power conversion according to the above parameters is already very mature in the prior art and will not be described in detail here.

[0083] In this embodiment, the set value of the direct-axis current of the access point is adjusted according to the deviation of the direct-axis voltage of the access point, and the set value of the quadrature-axis current of the access point is adjusted according to the deviation of the quadrature-axis voltage of the access point. The power converter is controlled to perform power conversion according to the deviation between the set value of the direct-axis current of the access point and the feedback value, the deviation between the set value of the quadrature-axis current of the access point and the feedback value, and the phase of the voltage of the access point. Therefore, when the new energy power generation equipment is stable, the direct-axis voltage of the access point is stable at its set value, and the quadrature-axis voltage of the access point is stable at its set value. Therefore, when the power system is in a steady state, the voltage of the access point is stable at its set value.

[0084] Another embodiment of the present application provides a specific implementation of step S320. The specific process can be found in Figure 5 ( Figure 5 Only in Figure 4 The specific steps include:

[0085] S510: Adjust the set value of the effective value of the voltage at the access point according to the deviation of the effective value of the voltage at the access point.

[0086] Typically, the voltage at the access point is an AC voltage, so the effective value of the voltage at the access point refers to: the effective value of the AC voltage here.

[0087] The deviation of the voltage effective value of the access point is equal to the set value of the voltage effective value of the access point minus the feedback value of the voltage effective value of the access point. The feedback value of the voltage effective value of the access point is the effective value of the actual voltage of the access point obtained by sampling. As for how to sample the voltage of the access point, it is already very mature in the prior art and will not be described in detail here.

[0088] S520 , adjusting the set value of the direct-axis current of the access point according to the deviation between the set value of the direct-axis voltage of the access point and the adjustment value of the set value of the effective value of the voltage of the access point.

[0089] The adjustment value of the set value of the effective voltage value of the access point refers to the value of the set value of the effective voltage value of the access point after the set value of the effective voltage value of the access point is adjusted.

[0090] It should be noted that the direct-axis voltage of the access point and the direct-axis current of the access point have been described in detail in the above embodiments and will not be described again here.

[0091] S530: Adjust the set value of the quadrature-axis current of the access point according to the deviation of the quadrature-axis voltage of the access point.

[0092] It should be noted that the quadrature-axis voltage of the access point, the quadrature-axis current of the access point, and the quadrature-axis voltage deviation of the access point have been described in detail in the above embodiments and will not be described again here.

[0093] Wherein, the set value of the quadrature axis voltage of the access point is equal to zero.

[0094] S540, controlling the power converter to perform power conversion according to the deviation between the set value and the feedback value of the direct-axis current at the access point, the deviation between the set value and the feedback value of the quadrature-axis current at the access point, and the phase of the voltage at the access point.

[0095] It should be noted that the direct-axis current of the access point, the quadrature-axis current of the access point, the set value and feedback value of the direct-axis current of the access point, the set value and feedback value of the quadrature-axis current of the access point, and the phase of the voltage of the access point have been described in detail in the above embodiments and will not be repeated here. In addition, how to control the power converter to perform power conversion according to the above parameters is already very mature in the prior art and will not be described in detail here.

[0096] In this embodiment, when the new energy power generation equipment is stable, the quadrature-axis voltage of the access point is stably equal to zero, and the direct-axis voltage of the access point is stably at the set value of the effective value of the voltage of the access point. Therefore, in the process of controlling the power converter to perform power conversion, it is no longer necessary to consider the phase of the quadrature-axis current of the access point and the voltage of the access point. Therefore, the phase error of the voltage of the access point can be reduced, and the influence on the power conversion of the power converter is reduced. Therefore, compared with the previous embodiment, the present embodiment improves the control accuracy of the steady-state control method, and further compared with the previous embodiment, the present embodiment improves the control accuracy of the transient control method.

[0097] Another embodiment of the present application also provides another specific implementation of step S320, which differs from the previous implementation in that:

[0098] In this embodiment, in step S510, the setting value of the effective value of the voltage of the access point is adjusted in a proportional manner according to the deviation of the effective value of the voltage of the access point.

[0099] Typically, in order to improve the control accuracy of the steady-state control method, in step S510, the adjustment methods for adjusting the set value of the effective voltage value of the access point according to the deviation of the effective voltage value of the access point include at least one of proportional adjustment, integral adjustment, and differential adjustment, and cannot include only proportional adjustment.

[0100] In this embodiment, since the response speed of proportional regulation is faster than that of integral regulation and differential regulation, the regulation mode of adjusting the set value of the voltage effective value of the access point according to the deviation of the voltage effective value of the access point is replaced by proportional regulation, so that the response speed of the steady-state control method is accelerated, and the steady-state control method is more suitable for the situation that the power grid is in a transient state, so that when the power system is in a transient state, the voltage of the access point can be made more stable, thereby improving the control accuracy of the transient control method.

[0101] Another embodiment of the present application provides another specific implementation of step S320. The specific process can be found in Figure 6 ( Figure 6 Only in Figure 5 ), this implementation mode further includes the following steps before step S520 in the previous implementation mode:

[0102] S610: Adjust the set value of the effective value of the voltage of the access point according to the reactive power deviation of the access point.

[0103] The reactive power of the access point is equal to the reactive power of the power generation power of the new energy power generation device in the new energy power generation equipment.

[0104] The deviation of the reactive power of the access point is equal to the reactive power setting value of the access point minus the reactive power feedback value of the access point. The reactive power setting value of the access point is set according to the actual control requirements and is not specifically limited here. The reactive power feedback value of the access point is the actual value of the reactive power of the access point obtained by sampling. As for how to sample the reactive power of the access point, it is already very mature in the prior art and will not be described in detail here.

[0105] In this embodiment, when the renewable energy power generation equipment is stable, the reactive power of the above-mentioned access point is stabilized at its set value. Therefore, if multiple renewable energy generation equipment is connected in parallel, the set value of the reactive power of the access points of the multiple renewable energy generation equipment is set to the same value. Then, the reactive power of the access points of the multiple renewable energy generation equipment is the same, thereby reducing the possibility of reactive commutation between the multiple renewable energy generation equipment.

[0106] Another embodiment of the present application also provides another specific implementation method of the transient control method of the new energy power generation equipment, and its specific process can be found in Figure 7 ( Figure 7 Only step S710 after step S110 and step S210 is taken as an example. Figure 6 This embodiment further includes the following steps before step S120 in the above embodiment:

[0107] S710. When the power system is in a transient state, the power deviation of the access point in the steady-state control method is limited according to the current limit of the new energy power generation equipment.

[0108] It should be noted that the power of the access point and the deviation of the power of the access point have been described in detail in the above embodiments and will not be repeated here.

[0109] In practical applications, the execution order of step S710, step S110, and step S210 can be arranged and combined at will, and is not specifically limited here. It can be determined according to the specific situation and is within the protection scope of this application.

[0110] As can be seen from the above, limiting the deviation of the power of the access point is equivalent to limiting the adjustment amount of the power of the access point, that is, equivalent to limiting the power of the access point. In addition, since the deviation of the power of the access point is limited according to the current limit of the new energy power generation equipment, the power of the access point will not exceed the current limit of the new energy power generation equipment, thereby protecting the new energy power generation equipment, thereby improving the safety performance of the new energy power generation equipment, and further providing the safety of the above power system.

[0111] by Figure 7 As an example, if the steady-state control method adopts the transient control method shown in Figure 3 The control block diagram corresponding to the transient control method is shown in FIG8 :

[0112] Vd is the set value of the direct-axis voltage of the above-mentioned access point, and Ud is the feedback value of the direct-axis voltage of the above-mentioned access point. Vq is the set value of the quadrature-axis voltage of the above-mentioned access point, and Uq is the feedback value of the quadrature-axis voltage of the above-mentioned access point. P controller represents proportional regulation. id_ref is the set value of the direct-axis current of the above-mentioned access point, and id_mea is the feedback value of the direct-axis current of the above-mentioned access point. iq_ref is the set value of the quadrature-axis current of the above-mentioned access point, and iq_mea is the feedback value of the quadrature-axis current of the above-mentioned access point. Pref is the set value of the power generation of the new energy power generation equipment, and Pmea is the feedback value of the power generation of the new energy power generation equipment. P0 is the power limit of the power grid, and i0 is the current limit of the new energy power generation equipment. Limitation means limiting Pref according to P0 and i0. θ is the phase of the voltage of the above-mentioned access point. Phase generation means adjusting θ according to Pref-Pmea.

[0113] by Figure 7 As an example, if the steady-state control method adopts the transient control method shown in Figure 6 The control block diagram corresponding to the transient control method is as follows: Fig. 9 As shown:

[0114] Vref is the set value of the voltage effective value of the access point, and Vmea is the feedback value of the voltage effective value of the access point. Eref is the adjustment value of the set value of the voltage effective value of the access point. Qref is the set value of the reactive power of the access point, and Qmea is the feedback value of the reactive power of the access point. In addition to the above parameters, other parameters are the same as Figure 8 The same is not repeated here.

[0115] Another embodiment of the present application provides a new energy power generation equipment, the specific structure of which can be seen in Fig.10 ( Fig.10 Only a wind turbine is used as an example for demonstration), specifically including: a new energy power generation device 10, a power converter 20 and a controller 30. The connection relationship between the various components is as follows:

[0116] The AC side of the power converter 20 serves as the access point of the new energy power generation equipment; the other side of the power converter 20 is connected to the new energy power generation device 10. Both the new energy power generation device 10 and the power converter 20 are controlled by the controller 30, and the controller 30 is used to execute the transient control method of the new energy power generation equipment provided in the above embodiment.

[0117] In a specific example, if Fig.10As shown, the new energy power generation device 10 is a wind turbine 11, and the power converter 20 includes: a machine-side converter 21 and a grid-side converter 22. The wind turbine 11 is connected to the AC side of the machine-side converter 21, and the DC side of the machine-side converter 21 is connected to the DC side of the grid-side converter 22. The AC side of the grid-side converter 22 serves as an access point for the new energy power generation equipment.

[0118] In another specific example, the new energy power generation device 10 is a photovoltaic power generation device, and the power converter 20 includes a photovoltaic inverter. The photovoltaic power generation device is connected to the DC side of the photovoltaic inverter, and the AC side of the photovoltaic inverter serves as an access point for the new energy power generation equipment.

[0119] The above two examples only show two specific implementation methods of the new energy power generation equipment. In practical applications, including but not limited to these, as long as the implementation methods including the new energy power generation device 10 and the power converter 20 are within the protection scope of this application, no specific limitation is made here and it may depend on the specific situation.

[0120] In this embodiment, since the controller 30 executes the transient control method of the new energy power generation equipment provided in the above embodiment, this embodiment can achieve the various effects achieved in the above embodiment, which will not be repeated here.

[0121] Another embodiment of the present application provides a power generation system, the specific structure of which can be seen in Fig.11 ( Fig.11 Only the new energy power generation equipment 300 including a wind turbine is used as an example for demonstration), specifically including: a transformer 100 and at least one new energy power generation equipment 300 provided by the above embodiment.

[0122] The access point of each new energy power generation device is connected to a first side of the transformer 100 , and the second side of the transformer 100 is connected to a power grid 200 in the power system.

[0123] It should be noted that the connection lines between the second side of the transformer 100 and the power grid 200 are divided into medium voltage lines and transmission lines. In actual applications, there will be different voltage levels in different scenarios. Both are very mature in the existing technology and are not specifically limited here.

[0124] In this embodiment, since the power generation system includes the new energy power generation equipment 300 provided in the above embodiment, this embodiment can achieve various effects achieved in the above embodiment, which will not be described in detail here.

[0125] For the above description of the disclosed embodiments, the features recorded in each embodiment in this specification can be replaced or combined with each other, so that professionals in the field can implement or use the present application. The above is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as above with a preferred embodiment, it is not used to limit the present invention. Any technician familiar with the field can make many possible changes and modifications to the technical solution of the present invention using the methods and technical contents disclosed above without departing from the scope of the technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of protection of the technical solution of the present invention.

Claims

1. A transient control method for new energy power generation equipment, characterized in that: include: When the power system where the new energy power generation equipment is located is in a transient state, the set value of the power generation power of the new energy power generation equipment in the steady-state control method of the new energy power generation equipment is limited according to the limited power of the power grid in the power system; the steady-state control method is a control method for achieving a stable voltage at the access point of the new energy power generation equipment when the power system is in a steady state; According to the steady-state control method, the new energy power generation equipment is controlled.

2. The transient control method for new energy power generation equipment according to claim 1, characterized in that: Before controlling the new energy power generation equipment according to the steady-state control method, the method further includes: When the power system is in a transient state, the adjustment method for the set value of the direct-axis current of the access point and the adjustment method for the set value of the quadrature-axis current of the access point in the steady-state control method are replaced with proportional adjustment.

3. The transient control method for renewable energy power generation equipment according to claim 1, characterized in that: The steady-state control method comprises: adjusting the phase of the voltage at the access point according to the deviation between the set value and the feedback value of the generated power; According to the set value of the direct-axis voltage of the access point, the set value of the quadrature-axis voltage of the access point, and the phase of the voltage of the access point, the power converter in the new energy power generation equipment is controlled to perform power conversion.

4. The transient control method for new energy power generation equipment according to claim 3, characterized in that: According to the set value of the direct-axis voltage of the access point, the set value of the quadrature-axis voltage of the access point, and the phase of the voltage of the access point, the power converter in the new energy power generation equipment is controlled to perform power conversion, including: adjusting a set value of the effective value of the voltage at the access point according to a deviation of the effective value of the voltage at the access point; adjusting the set value of the direct-axis current of the access point according to the deviation between the set value of the direct-axis voltage of the access point and the adjustment value of the set value of the effective value of the voltage of the access point; According to the deviation of the quadrature axis voltage of the access point, the set value of the quadrature axis current of the access point is adjusted; the set value of the quadrature axis voltage of the access point is equal to zero; The power converter is controlled to perform power conversion according to the deviation between the set value and the feedback value of the direct-axis current at the access point, the deviation between the set value and the feedback value of the quadrature-axis current at the access point, and the phase of the voltage at the access point.

5. The transient control method for new energy power generation equipment according to claim 4, characterized in that: Before adjusting the set value of the direct-axis current of the access point according to the deviation between the set value of the direct-axis voltage of the access point and the adjustment value of the set value of the effective value of the voltage of the access point, the method further includes: According to the reactive power deviation of the access point, the set value of the effective voltage value of the access point is adjusted.

6. The transient control method for new energy power generation equipment according to claim 4, characterized in that: The adjustment method for adjusting the set value of the effective value of the voltage of the access point according to the deviation of the effective value of the voltage of the access point is proportional adjustment.

7. The transient control method for new energy power generation equipment according to claim 3, characterized in that: According to the set value of the direct-axis voltage of the access point, the set value of the quadrature-axis voltage of the access point, and the phase of the voltage of the access point, the power converter in the new energy power generation equipment is controlled to perform power conversion, including: adjusting a set value of a direct-axis current of the access point according to a deviation of a direct-axis voltage of the access point; According to the deviation of the quadrature-axis voltage of the access point, adjusting the set value of the quadrature-axis current of the access point; The power converter is controlled to perform power conversion according to the deviation between the set value and the feedback value of the direct-axis current at the access point, the deviation between the set value and the feedback value of the quadrature-axis current at the access point, and the phase of the voltage at the access point.

8. The transient control method for new energy power generation equipment according to any one of claims 1 to 7, characterized in that: Also includes: When the power system is in a transient state, the set value of the power generation in the steady-state control method is limited according to the current limit of the new energy power generation equipment.

9. A new energy power generation equipment, characterized in that: include: New energy power generation devices, power converters and controllers; among which: The AC side of the power converter serves as an access point for the new energy power generation equipment; The other side of the power converter is connected to the new energy power generation device; The new energy power generation device and the power converter are both controlled by the controller, and the controller is used to execute the transient control method of the new energy power generation equipment as described in any one of claims 1 to 8.

10. A power generation system, characterized in that: It comprises: a transformer and at least one new energy power generation equipment according to any one of claims 1 to 9; wherein: Each access point of the new energy power generation equipment is connected to the first side of the transformer, and the second side of the transformer is connected to the power grid in the power system.

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