A method and device for calculating the inertia time constant of a voltage source wind turbine generator set

Abstract

The present invention discloses a method and device for calculating the inertia time constant of a voltage source wind turbine. The method comprises: establishing a simulation test model for connecting a voltage source wind turbine to a power grid, applying a step disturbance to the active power of the voltage source wind turbine within the simulation test model, obtaining an active power curve output by the voltage source wind turbine, and calculating the inertia time constant of the voltage source wind turbine based on the active power curve. This method can be used to establish a method for obtaining key control parameters of the voltage source wind turbine. The method is suitable for analyzing and evaluating the inertia response characteristics of the voltage source wind turbine when connected to the grid, and lays a research foundation for the promotion, application, and safe and stable operation of voltage source wind turbines.

Description

Technical Field

[0001] The present invention relates to the field of control technology, and in particular to a method and device for calculating the inertia time constant of a voltage source type wind turbine generator set. Background Art

[0002] Voltage source control is a new type of wind turbine control method that has developed rapidly in recent years. It no longer relies on a phase-locked loop to achieve synchronization with the power grid. Instead, it achieves synchronization by simulating the rotor motion equations of the synchronous generator. It can also simulate the inertia response of the synchronous generator, providing the necessary inertia support and active power response when the grid frequency changes, effectively improving the frequency stability of the power system.

[0003] The moment of inertia of a power system is a key indicator of its stability. The moment of inertia is a measure of the inertia of a rigid body rotating about its axis. For a power system, this indicates its ability to maintain its original state of motion in the face of disturbances. The greater the power system's moment of inertia, the greater its ability to maintain stability under disturbances, and the greater the power system's stability. For power systems, the inertia time constant is a reflection of the system's moment of inertia.

[0004] The control response time, control accuracy, and external characteristics of voltage-source wind turbines under grid frequency and voltage fluctuations and fault ride-through conditions differ significantly from those of conventional current-source wind turbines. Currently, research on control performance testing and evaluation methods for voltage-source wind turbines is lacking, and the technology for extracting key control parameters through external characteristic testing is still immature. As inertia response is a key indicator for evaluating the active support performance of a turbine, testing and extracting the inertia time constant of voltage-source wind turbines is of great significance. Summary of the Invention

[0005] The present invention provides a method for calculating the inertia time constant of a voltage source type wind turbine generator set, which is used to solve the problem of the current lack of test and calculation of the inertia time constant of a voltage source type wind turbine generator set. The method comprises:

[0006] Establish a simulation test model for voltage source wind turbines connected to the power grid;

[0007] Applying a step disturbance to the active power of the voltage source wind turbine generator set in the simulation test model;

[0008] Obtaining an active power curve output by the voltage source wind turbine generator set;

[0009] The inertia time constant of the voltage source wind turbine generator set is calculated according to the active power curve.

[0010] In one embodiment, applying a step disturbance to the active power of the voltage source wind turbine generator system in the simulation test model includes:

[0011] Setting the active power and terminal voltage reference values of the voltage source type wind turbine generator set;

[0012] In one embodiment, applying a step disturbance to the active power of the voltage source wind turbine generator system in the simulation test model further includes:

[0013] When the active power of the voltage source type wind turbine generator set and the terminal voltage reference value are set, a step disturbance is applied to the active power of the voltage source type wind turbine generator set in the simulation test model.

[0014] In one embodiment, obtaining the active power curve output by the voltage source wind turbine generator system includes:

[0015] Obtaining the three-phase voltage and three-phase current output by the voltage source type wind turbine generator set;

[0016] The active power output by the voltage source wind turbine generator set is calculated according to the three-phase voltage and the three-phase current.

[0017] In one embodiment, the calculating the inertia time constant of the voltage source wind turbine generator system according to the active power curve further includes:

[0018] Measure the peak time t of the active power response of the voltage source wind turbine p ;

[0019] Measure the maximum overshoot M of the active power response of the voltage source wind turbine p .

[0020] In one embodiment, the calculating the inertia time constant of the voltage source wind turbine generator system according to the active power curve further includes:

[0021] An active power control model of the voltage source wind turbine generator system is established.

[0022] In one embodiment, the calculating the inertia time constant of the voltage source wind turbine generator system according to the active power curve further includes:

[0023] According to the active power control algorithm, the transfer function of the input and output of the active power control model is established:

[0024]

[0025] Among them, K f is the primary frequency modulation coefficient, T j is the inertia time constant, K p is the active power angle proportional coefficient.

[0026] In one embodiment, the method for calculating the inertia time constant of a voltage source wind turbine generator system further includes:

[0027] According to the maximum overshoot M p Calculating a damping ratio ζ of the transfer function;

[0028] According to the peak time t p and the maximum overshoot M p Calculate the natural frequency ω of the transfer function n .

[0029] In one embodiment, the calculating the inertia time constant of the voltage source wind turbine generator system according to the active power curve further includes:

[0030] According to the natural frequency ω n and active power angle proportional coefficient K p Calculate the inertia time constant of the voltage source wind turbine generator system.

[0031] The present invention provides a device for calculating the inertia time constant of a voltage source type wind turbine generator set, comprising:

[0032] A construction module for establishing a simulation test model for connecting a voltage source wind turbine to the power grid;

[0033] A disturbance module, configured to apply a step disturbance to the active power of the voltage source wind turbine generator set in the simulation test model;

[0034] An acquisition module, configured to acquire an active power curve output by the voltage source type wind turbine generator set;

[0035] A calculation module is used to calculate the inertia time constant of the voltage source wind turbine generator set according to the active power curve.

[0036] The present invention provides a method and system for calculating the inertia time constant of a voltage-source wind turbine. Compared to existing solutions, this method establishes a simulation test model of a voltage-source wind turbine connected to a power grid, applies a step disturbance to the active power of the voltage-source wind turbine within the simulation test model, obtains an active power curve output by the voltage-source wind turbine, and calculates the inertia time constant of the voltage-source wind turbine based on the active power curve. This method enables rapid and accurate calculation of the inertia time constant of the voltage-source wind turbine, and further reflects the inertia response performance of the wind turbine and its active support performance for the power grid based on the inertia time constant. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0038] Figure 1 A flow chart of a method for calculating the inertia time constant of a voltage source type wind turbine generator system according to an embodiment of the present invention is shown;

[0039] Figure 2 A schematic diagram of a simulation test model in an embodiment of the present invention is shown;

[0040] Figure 3 FIG2 shows a schematic diagram of an active power control model in an embodiment of the present invention;

[0041] Figure 4 shows a model parameter table of a simulation test model in one embodiment of the present invention;

[0042] Figure 5 shows an active power curve output by a simulation test model in one embodiment of the present invention;

[0043] Figure 6 The figure shows a structural block diagram of an inertia time constant calculation device for a voltage source type wind turbine generator set in one embodiment of the present invention. DETAILED DESCRIPTION

[0044] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. It should be noted that although the description of these embodiments is intended to help understand the present invention, it does not constitute a limitation of the present invention. The specific structural and functional details disclosed herein are merely intended to describe exemplary embodiments of the present invention. However, the present invention can be embodied in many alternative forms, and it should not be understood that the present invention is limited to the embodiments set forth herein.

[0045] With the rapid development of wind power in my country, the number of wind turbines connected to weak end-point grids in some provinces and regions of the "Three Norths" region is increasing. This inability of wind turbines to actively support the grid increases risks to the safe and stable operation of the power system. In this context, it is becoming an industry consensus that wind turbines must be able to actively support the grid. Voltage-source wind turbines, with their ability to autonomously reduce voltage and actively support the grid, offer frequency and voltage regulation characteristics similar to conventional synchronous turbines, making them an important solution to addressing the inability to actively support the grid.

[0046] The control response time, control accuracy, and external characteristics of voltage-source wind turbines under grid frequency fluctuations, voltage fluctuations, and fault ride-through conditions differ significantly from those of conventional current-source wind turbines. However, limited research has focused on the control response characteristics during active frequency and voltage regulation. Furthermore, research on control performance testing and evaluation methods for voltage-source wind turbines is still inadequate, and the technology for extracting key control parameters through external characteristic testing is still immature. As a key indicator of active support performance, inertia response testing and extracting the inertia time constant of voltage-source wind turbines is of great significance.

[0047] The present invention provides a method for calculating the inertia time constant of a voltage source type wind turbine generator set. Figure 1 As shown, the following steps may be included:

[0048] S101. Establish a simulation test model for connecting a voltage source wind turbine to the grid;

[0049] In some embodiments, as Figure 2 As shown, when establishing a simulation test model for connecting a voltage source wind turbine to a power grid, it is necessary to simulate the actual operating scenario of the voltage source wind turbine. Specifically, the simulation test model may include a voltage source wind turbine, transformer 1, and transformer 2. The voltage source wind turbine is connected to one end of transformer 1. The other end of transformer 1 is connected to one end of transformer 2 via a line. The other end of transformer 2 is connected to an infinite bus.

[0050] It should be noted that, in some embodiments, the above-mentioned simulation test model may adopt one or more of physical simulation, computer simulation (mathematical simulation), and semi-physical simulation. This application does not specifically limit the type of the simulation test model established.

[0051] S102. Applying a step disturbance to the active power of the voltage source wind turbine in the simulation test model;

[0052] In some embodiments, before applying a step disturbance to the active power of the voltage source type wind turbine in the simulation test model, it is necessary to set the reference values of the active power and terminal voltage of the voltage source type wind turbine. Usually, the reference values of the active power and terminal voltage of the voltage source type wind turbine are both set to 1, that is, P ref =1,U ref =1. After setting the reference values of the active power and terminal voltage, at a certain moment, such as t0, a step disturbance ΔP is applied to the set active power reference value of the voltage source wind turbine to test the changes in the relevant parameters of the model after the disturbance. The value of the step disturbance applied is usually ΔP = 0.1P ref , this application does not make any specific limitation on the value of the applied step disturbance.

[0053] S103. Obtaining the active power curve output by the voltage source wind turbine;

[0054] In some embodiments, after a step disturbance is applied to the active power of the voltage source type wind turbine in the simulation test model, an active power curve output by the voltage source type wind turbine can be obtained. It should be noted that when obtaining the active power curve output by the voltage source type wind turbine, it is necessary to obtain the three-phase voltages ua, ub, uc and the three-phase currents ia, ib, ic output by the voltage source type wind turbine. The active power output by the voltage source type wind turbine is calculated according to the three-phase voltages ua, ub, uc and the three-phase currents ia, ib, ic using the following formula (1);

[0055] P e =u a i a +u b i b +u c i c (1)

[0056] After calculating the active power output by the voltage source type wind turbine generator set, the active power curve output by the voltage source type wind turbine generator set can be determined.

[0057] S104. Calculating the inertia time constant of the voltage source wind turbine generator system according to the active power curve;

[0058] In some embodiments, the peak time t of the active power response of the voltage source type wind turbine generator can be measured according to the active power curve. p , and measuring the maximum overshoot M of the active power response of the voltage source wind turbine p Wherein, the peak time t p It is used to indicate the time required for the response curve of the system to reach the first peak after the system is disturbed; the maximum overshoot M p Used to express the ratio of the instantaneous maximum deviation value (Xmax) of the controlled variable to its steady-state value (X(∞)) under the action of a step input.

[0059] In some embodiments, the peak time t p and the maximum overshoot M p , calculate the natural frequency ω of the transfer function n and the damping ratio ζ.

[0060] According to the unit step response of the second-order system, the peak time t p It can be expressed by the following formula:

[0061]

[0062] The maximum overshoot Mp can be expressed by the following formula:

[0063]

[0064] Among them, ω d is the oscillation angular frequency, ω n is the natural frequency and ζ is the damping ratio.

[0065] To this end, the natural frequency ω can be calculated according to formula (2) and formula (3) n and the damping ratio ζ.

[0066] The transfer function may be a transfer function of input and output of an active power control model of a voltage source type wind turbine generator set. Specifically, an active power control model of the voltage source type wind turbine generator set may be established; and a transfer function of input and output of the active power control model may be established based on an active power control algorithm.

[0067] The active power control model can be Figure 3 As shown. Among them, P ref is the active power reference value of the voltage source wind turbine, P e is the output active power of the voltage source wind turbine, K f is the primary frequency modulation coefficient, T j is the inertia time constant, K p The active power control model adjusts the output active power P of the voltage source wind turbine by adjusting the virtual speed ω and the virtual rotor angle θ. e .

[0068] The transfer function can be expressed as:

[0069]

[0070] Among them, K f is the primary frequency modulation coefficient, T j is the inertia time constant, K p is the active power angle proportional coefficient.

[0071] In some embodiments, the natural frequency ω n and the damping ratio ζ, and calculate the inertia time constant of the voltage source wind turbine generator set.

[0072] Based on classical control theory, the natural frequency of the transfer function (4) can be obtained as:

[0073]

[0074] The damping ratio of the transfer function (4) can be obtained as:

[0075]

[0076] Therefore, the active power angle proportional coefficient K can be calculated according to formula (6): p ; According to the active power angle proportional coefficient K p and the natural frequency ω n , through the formula Calculate the inertia time constant T j .

[0077] Among them, the formula It can be obtained according to formula (5).

[0078] The present invention provides a method and system for calculating the inertia time constant of a voltage-source wind turbine. Compared to existing solutions, this method establishes a simulation test model of a voltage-source wind turbine connected to a power grid, applies a step disturbance to the active power of the voltage-source wind turbine within the simulation test model, obtains an active power curve output by the voltage-source wind turbine, and calculates the inertia time constant of the voltage-source wind turbine based on the active power curve. This method enables rapid and accurate calculation of the inertia time constant of the voltage-source wind turbine, and further reflects the inertia response performance of the wind turbine and its active support performance for the power grid based on the inertia time constant.

[0079] like Figure 4 As shown in FIG, it is a model parameter table of the simulation test model established by the present application based on matlab or simulink. At t = 2s, a step disturbance ΔP = 0.1P is applied to the active power reference value of the voltage source type wind turbine generator set. ref , the output active power curve can be obtained by formula (1) as follows Figure 5 shown.

[0080] Use Figure 5 The active power curve shown can measure the peak time tp=0.02s and the maximum overshoot M of the active power response of the voltage source wind turbine generator system. p =20%.

[0081] According to formula (2) and formula (3), the natural frequency ω of the transfer function can be obtained n =22.203rad / s and damping ratio ζ = 0.707. According to formula (6), the active power angle proportional coefficient K of the unit can be obtained p =5000. According to formula (5), the inertia time constant T of the voltage source wind turbine generator set can be calculated: j =10.142s.

[0082] Since the simulation test model was primarily designed to verify the accuracy of the proposed method, the accuracy of the calculated inertia time constant was verified by consulting the product manual of the voltage source wind turbine controller being tested. The inertia time constant for this voltage source wind turbine was set to 10 seconds. This demonstrates that the inertia time constant calculation method proposed in this invention can accurately obtain the actual value of this key control parameter and effectively evaluate the inertia response characteristics of the voltage source wind turbine.

[0083] Based on the same inventive concept, the embodiments of this specification also provide a device for calculating the inertia time constant of a voltage source type wind turbine, as described in the following embodiments. Since the principle of solving the problem by the calculation device is similar to that of the calculation method, the implementation of the calculation device can refer to the implementation of the calculation method, and the repeated parts will not be repeated. As used below, the term "unit" or "module" can be a combination of software and / or hardware that implements the predetermined function. Although the device described in the following embodiments is preferably implemented in software, it is also possible and conceivable to implement it in hardware, or a combination of software and hardware. Figure 6 This is a structural block diagram of a voltage source type wind turbine inertia time constant calculation device according to an embodiment of this specification. Figure 6 As shown, it includes: a construction module 601, a disturbance module 602, an acquisition module 603 and a calculation module 604. The structure is described below.

[0084] Construction module 601 is used to establish a simulation test model for connecting a voltage source wind turbine to a power grid;

[0085] A disturbance module 602 is configured to apply a step disturbance to the active power of the voltage source wind turbine generator system in the simulation test model;

[0086] An acquisition module 603 is configured to acquire an active power curve output by the voltage source wind turbine generator system;

[0087] The calculation module 604 is configured to calculate the inertia time constant of the voltage source wind turbine generator system according to the active power curve.

[0088] In some embodiments, the simulation test model includes a voltage source wind turbine, a first transformer and a second transformer; the voltage source wind turbine is connected to one end of the first transformer, the other end of the first transformer is connected to one end of the second transformer through a line, and the other end of the second transformer is connected to an infinite bus.

[0089] In some embodiments, the disturbance module 602 is specifically configured to set the active power and terminal voltage reference values of the voltage source wind turbine generator set, and apply a step disturbance according to the set active power and terminal voltage reference values.

[0090] In some embodiments, the acquisition module 603 is specifically used to obtain the three-phase voltage and three-phase current output by the voltage source wind turbine generator set, and calculate the active power output by the voltage source wind turbine generator set based on the three-phase voltage and the three-phase current.

[0091] In some embodiments, the calculation module 604 is specifically used to measure the peak time t of the active power response of the voltage source wind turbine generator system according to the active power curve. p and the maximum overshoot M p ; According to the peak time t p and the maximum overshoot M p , calculate the natural frequency ω of the transfer function n and damping ratio ζ; according to the natural frequency ω n and the damping ratio ζ, and calculate the inertia time constant of the voltage source wind turbine generator set.

[0092] In summary, embodiments of the present invention provide a method and system for calculating the inertia time constant of a voltage-source wind turbine. Compared to existing technical solutions, this method establishes a simulation test model for connecting a voltage-source wind turbine to a power grid, applies a step disturbance to the active power of the voltage-source wind turbine within the simulation test model, obtains the active power curve output by the voltage-source wind turbine, and calculates the inertia time constant of the voltage-source wind turbine based on the active power curve. This method can be used to determine key control parameters of a voltage-source wind turbine, which is suitable for analyzing and evaluating the inertia response characteristics of voltage-source wind turbines connected to the grid, laying a research foundation for the widespread application and safe and stable operation of voltage-source wind turbines.

[0093] Obviously, those skilled in the art should understand that the various modules or steps of the above-mentioned embodiments of this specification can be implemented using a general-purpose computing device, they can be concentrated on a single computing device, or distributed across a network composed of multiple computing devices. Alternatively, they can be implemented using program code executable by the computing device, so that they can be stored in a storage device and executed by the computing device. In some cases, the steps shown or described can be performed in a different order than herein, or they can be made into separate integrated circuit modules, or multiple modules or steps can be made into a single integrated circuit module for implementation. Thus, the embodiments of this specification are not limited to any specific combination of hardware and software.

[0094] It should be understood that the above description is intended to be illustrative and not limiting. Numerous embodiments and applications beyond the examples provided will be readily apparent to those skilled in the art upon reading the above description. Therefore, the scope of this specification should not be determined with reference to the above description, but rather with reference to the preceding claims, along with the full scope of equivalents to which such claims are entitled.

[0095] The above description is merely a preferred embodiment of this specification and is not intended to limit this specification. Those skilled in the art will readily appreciate that various modifications and variations to the embodiments of this specification are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this specification shall be within the scope of protection of this specification.

Claims

1. A method for calculating the inertia time constant of a voltage source wind turbine generator system, characterized in that: include: Establish a simulation test model for voltage source wind turbines connected to the power grid; Applying a step disturbance to the active power of the voltage source wind turbine generator set in the simulation test model; Obtaining an active power curve output by the voltage source wind turbine generator set; Calculating the inertia time constant of the voltage source wind turbine generator system according to the active power curve; Calculating the inertia time constant of the voltage source wind turbine generator set according to the active power curve includes: According to the active power curve, the peak time t of the active power response of the voltage source wind turbine is measured. p and the maximum overshoot M p ; According to the peak time t p and the maximum overshoot M p , calculate the natural frequency ω of the transfer function n and damping ratio ζ; the transfer function includes K f is the primary frequency modulation coefficient, T j is the inertia time constant, K p is the active power angle proportional coefficient; the natural frequency ω of the calculation transfer function n and the damping ratio ζ, including: According to the formula and Calculate the natural frequency ω of the transfer function n and damping ratio ζ; According to the natural frequency ω n and damping ratio ζ, calculate the inertia time constant of the voltage source type wind turbine generator set; the calculation of the inertia time constant of the voltage source type wind turbine generator set includes: according to the formula Calculate the active power angle proportional coefficient K p ; According to the active power angle proportional coefficient K p and the natural frequency ω n , through the formula Calculate the inertia time constant T j .

2. The method for calculating the inertia time constant of a voltage source wind turbine generator set according to claim 1, wherein: The simulation test model includes a voltage source wind turbine generator set, a first transformer and a second transformer; The voltage source wind turbine generator set is connected to one end of a first transformer, the other end of the first transformer is connected to one end of a second transformer via a line, and the other end of the second transformer is connected to an infinite bus.

3. The method for calculating the inertia time constant of a voltage source wind turbine generator set according to claim 1, wherein: The step disturbance is applied to the active power of the voltage source wind turbine generator set in the simulation test model, comprising: Setting the active power and terminal voltage reference values of the voltage source wind turbine generator set; Apply step disturbance according to the set active power and terminal voltage reference value.

4. The method for calculating the inertia time constant of a voltage source wind turbine generator set according to claim 1, wherein: The obtaining of the active power curve output by the voltage source wind turbine generator system includes: Obtaining the three-phase voltage and three-phase current output by the voltage source type wind turbine generator set; The active power output by the voltage source wind turbine generator set is calculated according to the three-phase voltage and the three-phase current.

5. The method for calculating the inertia time constant of a voltage source wind turbine generator set according to claim 1, wherein: The transfer function is constructed according to the following method: Establishing an active power control model of the voltage source wind turbine generator system; According to the active power control algorithm, a transfer function between the input and output of the active power control model is established.

6. A device for calculating the inertia time constant of a voltage source type wind turbine generator set, characterized in that: include: A construction module for establishing a simulation test model for connecting a voltage source wind turbine to the power grid; A disturbance module, configured to apply a step disturbance to the active power of the voltage source wind turbine generator set in the simulation test model; An acquisition module, configured to acquire an active power curve output by the voltage source type wind turbine generator set; a calculation module, configured to calculate the inertia time constant of the voltage source wind turbine generator system according to the active power curve; Calculating the inertia time constant of the voltage source wind turbine generator set according to the active power curve includes: According to the active power curve, the peak time t of the active power response of the voltage source wind turbine is measured. p and the maximum overshoot M p ; According to the peak time t p and the maximum overshoot M p , calculate the natural frequency ω of the transfer function n and damping ratio ζ; the transfer function includes K f is the primary frequency modulation coefficient, T j is the inertia time constant, K p is the active power angle proportional coefficient; the natural frequency ω of the calculation transfer function n and the damping ratio ζ, including: According to the formula and Calculate the natural frequency ω of the transfer function n and damping ratio ζ; According to the natural frequency ω n and damping ratio ζ, calculate the inertia time constant of the voltage source type wind turbine generator set; the calculation of the inertia time constant of the voltage source type wind turbine generator set includes: according to the formula Calculate the active power angle proportional coefficient K p ; According to the active power angle proportional coefficient K p and the natural frequency ω n , through the formula Calculate the inertia time constant T j .

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