Inertia phase-locked regulation method and system for new energy power generation with fast frequency response

Abstract

The application provides a new energy power generation inertia phase-locked regulation method and system with fast frequency response, and belongs to the technical field of new energy power generation. The phase-locked loop comprises a phase detector, a phase delay device, a loop filter and a voltage-controlled oscillator. The phase detector receives a three-phase alternating voltage signal of a grid connection point of a new energy power generation system, and performs coordinate transformation on the three-phase alternating voltage signal to a two-phase rotating coordinate system to obtain a q-axis component of the grid connection point voltage. The phase delay device receives the q-axis component of the grid connection point voltage and performs phase compensation on the q-axis component through a phase delay link. The loop filter is used to obtain a frequency deviation signal between an angle frequency of the phase-locked loop and an angle frequency of the grid connection point voltage. The voltage-controlled oscillator is used to integrate the frequency deviation signal between the angle frequency of the phase-locked loop and the angle frequency of the grid connection point voltage to obtain an output phase angle of the phase-locked loop. The application supports the lowest point of the system frequency, has strong universality, and can be applied to various new energy grid-connected power generation equipment connected through power electronics.

Description

Technical Field

[0001] This invention belongs to the field of new energy power generation technology, and more specifically, relates to a new energy power generation inertia phase-locked loop control method and system with fast frequency response. Background Technology

[0002] When a wind turbine is connected to the grid via power electronic equipment, the rapid action of this equipment decouples the rotor speed from the grid frequency, thus hiding the rotor's rotational inertia. Therefore, when a power shortage in the grid causes frequency changes, the wind turbine's output power remains constant; in other words, the wind turbine lacks inertial response capability. To simulate the inertial response characteristics of a traditional synchronous generator, most existing inertial control methods start from controlling the outer power loop to control the wind turbine rotor's kinetic energy and suppress grid frequency changes.

[0003] Existing wind turbine inertia control methods are mainly divided into two categories: one is virtual synchronous control. This method modifies the control loop of the power electronic equipment by analogy with traditional synchronous machines to achieve inertia support for the wind turbine. However, this control method completely overturns the vector control structure used in 100% of wind turbines, resulting in poor versatility and posing significant difficulties for equipment upgrades and modifications. The other category is virtual inertia control based on frequency measurement. This method introduces the measured frequency changes into the power outer loop to achieve a virtual inertia response for the wind turbine. However, when the frequency begins to rise, the decrease in power may cause a severe secondary frequency drop.

[0004] Furthermore, as a direct frequency measurement component, the phase-locked loop (PLL) inherently possesses frequency measurement information. Existing research indicates that modifying PLL parameters can achieve the inertial response of wind turbines; however, low-bandwidth PLLs have shorter support times and weaker support capabilities at the lowest frequency points. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a new energy power generation inertia phase-locked loop control method and system with fast frequency response, aiming to solve the problems of poor universality and weak support capability at the lowest frequency point of existing inertia support methods.

[0006] To achieve the above objectives, the present invention provides a new energy power generation inertia phase-locked loop control system with fast frequency response, comprising: a phase detector, a phase delay unit, a loop filter and a voltage-controlled oscillator connected in sequence.

[0007] The phase detector is used to receive the three-phase AC voltage signal at the grid connection point of the new energy power generation system, and to perform coordinate transformation on the three-phase AC voltage signal to a two-phase rotating coordinate system to obtain the q-axis component of the grid connection point voltage.

[0008] Phase delayers are used to delay the flow of electricity in renewable energy power generation systems after a frequency fault occurs. Phase compensation and amplitude attenuation are performed on the q-axis component of the grid connection point voltage to increase the phase difference between the phase angle of the phase-locked loop output and the phase angle of the stator voltage. This increases the power angle between the internal potential and the stator voltage in the new energy power generation system, thereby increasing the active power of the new energy power generation system and supporting the frequency drop of the new energy power generation system. Here, K is the phase compensation coefficient and s is the frequency domain parameter.

[0009] The loop filter is used to obtain the frequency deviation signal between the phase-locked loop angular frequency and the grid connection point voltage angular frequency;

[0010] A voltage-controlled oscillator is used to measure the frequency deviation signal between the phase-locked loop angular frequency and the grid connection point voltage angular frequency. The phase angle of the phase-locked loop is obtained by integration and used in the coordinate transformation stage of the control of new energy power generation system.

[0011] More preferably, the loop filter is a PI controller. or low-pass filter Among them, K p K is the proportionality coefficient. i is the integral coefficient, Ts is the time constant; s is the Laplace operator.

[0012] More preferably, the new energy power generation system includes a doubly-fed wind turbine, a direct-drive wind turbine, and photovoltaic power generation equipment.

[0013] More preferably, when the new energy power generation system is a doubly-fed wind turbine, the active power of the doubly-fed wind turbine during the dynamic process is:

[0014]

[0015] Where E is the internal potential; U s X is the stator voltage; s δ represents the stator reactance; δ represents the internal potential E and the stator voltage U. s The angle between them; θ ctrl θ is the angle between the internal potential E and the phase-locked coordinate system. s and θ pll These are the stator terminal voltage phase angle and the phase-locked loop output phase angle, respectively.

[0016] More preferably, the q-axis voltage component at the grid connection point is:

[0017] U sq pll =U s sin(θ s -θ pll )

[0018] Among them, U s The grid connection point voltage signal; U sqpll This represents the q-axis voltage component at the grid connection point.

[0019] Based on the phase-locked loop provided above, this invention provides a corresponding new energy power generation inertia phase-locked loop control method with fast frequency response, comprising the following steps:

[0020] A phase detector is used to receive the three-phase AC voltage signal at the grid connection point of the new energy power generation system, and the coordinate transformation of the three-phase AC voltage signal is performed to a two-phase rotating coordinate system to obtain the q-axis component of the grid connection point voltage.

[0021] After a frequency fault occurs in a new energy power generation system, the q-axis component of the grid connection point voltage is decelerated through a phase delay element. Phase compensation is performed to increase the phase difference between the phase angle of the phase-locked loop output and the phase angle of the stator voltage, thereby increasing the power angle between the internal potential and the stator voltage in the new energy power generation system, increasing the active power of the new energy power generation system, and supporting the frequency drop of the new energy power generation system; where K is the phase compensation coefficient and s is the Laplace operator.

[0022] A loop filter is used to obtain the frequency deviation signal between the phase-locked loop angular frequency and the grid connection point voltage angular frequency;

[0023] A voltage-controlled oscillator is used to analyze the frequency deviation signal between the phase-locked loop angular frequency and the grid connection point voltage angular frequency. The phase angle of the phase-locked loop is obtained by integration and used in the coordinate transformation stage of the control of new energy power generation system.

[0024] In a further preferred embodiment, the loop filter is a PI controller. or low-pass filter Among them, K p K is the proportionality coefficient. i is the integral coefficient, Ts is the time constant; s is the Laplace operator.

[0025] More preferably, the new energy power generation system includes: a doubly-fed wind turbine, a direct-drive wind turbine, and photovoltaic power generation equipment.

[0026] More preferably, when the new energy power generation system is a doubly-fed wind turbine, the active power of the doubly-fed wind turbine during the dynamic process is:

[0027]

[0028] Where E is the internal potential; U s X is the stator voltage; s δ represents the stator reactance; δ represents the internal potential E and the stator voltage U. s The angle between them; θ ctrl θ is the angle between the internal potential E and the phase-locked coordinate system. s and θpll These are the stator terminal voltage phase angle and the phase-locked loop output phase angle, respectively.

[0029] More preferably, the q-axis voltage component at the grid connection point is:

[0030] U sq pll =U s sin(θ s -θ pll )

[0031] Among them, U s The grid connection point voltage signal; U sq pll This represents the q-axis voltage component at the grid connection point.

[0032] In summary, the technical solutions conceived by this invention have the following beneficial effects compared with the prior art:

[0033] 1. This invention provides a method and system for inertia-based phase-locked loop (PLL) control of new energy power generation with fast frequency response. A phase delay element is added to the traditional PLL structure, improving the PLL's damping ratio. This allows the PLL's output phase to lag behind the grid phase near the system's oscillation frequency. Furthermore, the amplitude-frequency response of the PLL's output phase angle is consistently at or below 0 dB, decreasing with increasing system oscillation frequency. In other words, the faster the grid frequency drops, the smaller the ratio of the amplitude of the PLL's output phase angle change to the amplitude of the grid phase angle change. This invention's fast-frequency-response PLL control method for inertia-based new energy power generation allows for dynamic fluctuations between the control coordinate system and the actual coordinate system of new energy power generation equipment such as wind turbines during grid frequency faults. This provides the new energy equipment with inertia response capability, supporting grid frequency drops.

[0034] 2. This invention provides a new energy power generation inertia phase-locked loop control method and system with fast frequency response. When the phase-locked loop bandwidth is the same, it has a greater frequency support capability than the traditional phase-locked loop structure; conversely, when the frequency support capability is the same, it has a faster phase-locked loop bandwidth. Therefore, the new energy power generation inertia phase-locked loop control method with fast frequency response provided by this invention is more conducive to balancing the contradiction between frequency support capability and fast phase-locking.

[0035] 3. This invention provides a new energy power generation inertia phase-locked loop control method and system with fast frequency response. It retains the traditional vector control structure of existing new energy generator sets and only makes simple modifications to the control structure of the phase-locked loop. It has strong versatility and can be applied to various new energy power generation equipment connected to the grid via power electronics, such as doubly-fed wind turbines, direct-drive wind turbines, and photovoltaic power generation. Attached Figure Description

[0036] Figure 1 This is a flowchart of a new energy power generation inertia phase-locked control method with fast frequency response provided in an embodiment of the present invention;

[0037] Figure 2 This is a topology and control structure diagram of a doubly fed wind power generation system provided in an embodiment of the present invention;

[0038] Figure 3 This is a diagram of a novel phase-locked loop control structure in the new energy power generation inertia phase-locked loop control method with fast frequency response provided in this embodiment of the invention;

[0039] Figure 4(a) is the equivalent circuit of the doubly fed wind turbine provided in the embodiment of the present invention;

[0040] Figure 4(b) is a vector diagram of the doubly fed wind turbine provided in the embodiment of the present invention;

[0041] Figure 5 This is a typical phase-locked loop control structure diagram provided in the embodiments of the present invention;

[0042] Figure 6(a) is a waveform diagram of the output active power of the doubly fed wind turbine provided in an embodiment of the present invention;

[0043] Figure 6(b) is a system frequency waveform diagram provided in an embodiment of the present invention. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0045] Example

[0046] like Figure 1 As shown, this invention provides a method for controlling the inertia of new energy power generation with fast frequency response, comprising the following steps:

[0047] S1: The phase-locked loop phase detector obtains the three-phase AC voltage signal U at the grid connection point. sabc The coordinates of the voltage at the grid connection point are transformed to a two-phase rotating coordinate system to obtain the q-axis component of the voltage.

[0048] S2: The q-axis voltage component of the grid connection point is fed into a phase delay element and then into a loop filter to obtain the frequency deviation signal;

[0049] S3: The frequency deviation signal is sent to the voltage-controlled oscillator to obtain the phase angle of the phase-locked loop output, and the phase angle of the phase-locked loop output is used for the control of the new energy power generation equipment.

[0050] like Figure 2The diagram shows the topology and control structure of a doubly-fed induction generator (DFIG) wind power system. A phase-locked loop (PLL) is used to obtain the phase angle signal of the grid connection point voltage, enabling phase synchronization between the extreme voltage of the DFIG wind turbine and the grid connection point voltage. To respond to grid frequency events, the PLL control structure in the new energy power generation inertia PLL control method with fast frequency response provided in this invention is a novel PLL. The grid-side converter (GSC) control consists of a DC voltage outer loop and a grid-side current inner loop. dcref and U dc These are the DC voltage command value and the measured value, respectively. The error signal between the two is sent to the DC voltage loop PI controller, whose output is the grid-side d-axis current command value i. gdref Grid-side current q-axis command value i gqref Set to zero; the grid-side d-axis and q-axis current error signals are sent to the grid-side current loop PI controller, whose output is the d-axis and q-axis components V of the grid-side converter modulation voltage. gd and V gq V gd and V gq After coordinate transformation, the converter modulation voltage V in the three-phase AC coordinate system is obtained. g * The rotor-side converter RSC control consists of a speed loop, an outer reactive power loop, and an inner rotor current loop; P e The actual active power output of the doubly-fed induction generator (DFIG) is fed into the MPPT control to obtain the speed command value. Then, the speed loop error command is sent to the speed loop PI controller, whose output is the d-axis command value i of the rotor current. rdref The error signal of the rotor d-axis current is sent to Q. ref Q represents the reactive power command value for the doubly-fed induction generator (DFIG). e The reactive power measurement value and the error between them are fed into the rotor current loop PI controller to obtain the q-axis command value i of the rotor current. rqref The dq-axis component error of the rotor current is fed into the current loop PI controller to obtain the d and q-axis components V of the machine-side converter modulation voltage. rd and V rq V rd and V rq After coordinate transformation, the converter modulation voltage V in the three-phase AC coordinate system is obtained. r * ;

[0051] The novel phase-locked loop control structure used in this invention is as follows: Figure 3 As shown, U sabc The grid-connected point voltage signal in the three-phase AC coordinate system is transformed to obtain the q-axis component U of the grid-connected point voltage in the phase-locked coordinate system. sq pll Stator voltage orientation is adopted; under steady-state conditions, U sqpll =0, achieving phase synchronization between the stator voltage at the generator terminal and the grid connection point voltage; U sq pll The error signal with respect to 0 is processed by a phase compensation circuit. The signal is fed into a phase-locked loop (PLL) PI controller to orient the stator terminal voltage in steady state; the output of the PLL PI controller is the frequency deviation signal between the PLL angular frequency and the grid connection point voltage angular frequency (equivalent to the system frequency in a large signal); the system frequency is then fed into a voltage-controlled oscillator (VCO). Obtain the phase angle θ of the phase-locked loop output. pll Phase-locked loop output phase angle θ pll Used in various coordinate transformation processes;

[0052] More specifically, the q-axis voltage component (referred to as the large signal) at the grid connection point is:

[0053] U sq pll =U s sin(θ s -θ pll )

[0054] Among them, U s The grid connection point voltage signal; U sq pll This represents the q-axis voltage component at the grid connection point.

[0055] Linearizing the q-axis voltage component at the grid connection point yields:

[0056] ΔU sq pll =U s cos(θ s0 -θ pll0 )(Δθ s -Δθ pll )

[0057] ≈(Δθ s -Δθ pll )

[0058] Where, ΔU sq pll The change in the q-axis voltage component at the grid connection point during dynamic processes, also known as the small signal; Δθ s -Δθ pll The grid connection point voltage signal U s And the signal U generated by the internal oscillator of the phase-locked loop pll Phase angle deviation information between them;

[0059] Figure 4(a) shows the equivalent circuit of a stator-side doubly-fed wind turbine; where the internal potential vector E is defined as E = jX m I r; where X m For the mutual inductance reactance of the doubly fed motor, X s For stator reactance, I s U s These are the stator current and stator voltage (grid connection point voltage) vectors, respectively; Figure 4(b) shows the vector relationship diagram of a doubly-fed wind turbine; where U g d is the grid voltage vector; pll q pll These are the d-axis and q-axis of the phase-locked coordinate system, respectively; θ s θ pll and θ E These are the stator terminal voltage phase angle, phase-locked angle, and internal potential phase angle, respectively; θ ctrl δ is the angle between the internal potential E and the stator voltage U in the phase-locked coordinate system; δ is the angle between the internal potential E and the stator voltage U. s The angle between them;

[0060] More specifically, after a frequency fault occurs in the system, the grid voltage U g The phase of the stator voltage U changes. s The phase changes accordingly; the phase angle θ output by the new phase-locked loop pll Hysteresis of terminal voltage phase angle θ s The change in phase phase means that the phase-locked coordinate system cannot quickly track the change in the stator voltage phase; while the rotor current I r The phase θ of the internal potential E is controlled within the control coordinate system of the phase-locked loop. E Lagsing the stator voltage phase angle θ s The changes in frequency, taking frequency drops as an example, involve the relationship between E and U during this dynamic process. s The power angle δ between them will increase, the active power output of the doubly fed wind turbine will increase, thereby achieving the frequency drop of the support system.

[0061] More specifically, after a frequency fault occurs, the active power output of the doubly-fed wind turbine during the dynamic process is:

[0062]

[0063] During steady-state operation, the phase-locked output angle θ pll Phase angle θ with stator voltage s Overlap, after a frequency fault occurs in the system, θ pll >θ s This can increase the active power output, thereby supporting the system frequency drop.

[0064] Furthermore, to illustrate the performance of the new energy power generation inertia phase-locked loop control method with fast frequency response provided by this invention, the method is compared with the frequency support characteristics of a typical doubly-fed wind turbine under phase-locked loop control. Verification was performed under the same phase-locked loop controller parameters and the same bandwidth.

[0065] Typical phase-locked loop control structure as follows Figure 5 As shown, it mainly consists of a phase detector, a low-pass filter, and a voltage-controlled oscillator. Its biggest difference from the phase-locked loop structure used in the fast-frequency-response inertia phase-locked loop control method for new energy power generation provided in this invention is the lack of a phase delay element. This results in a difference in the phase-locked angle θ during dynamic processes when using conventional phase-locked loop parameters in typical phase-locked control. pll Fast tracking of stator voltage phase angle θ s The changes in frequency make it impossible to provide frequency support capabilities.

[0066] To further illustrate the control effect of the new energy power generation inertia phase-locked loop control method with fast frequency response proposed in this invention, a specific embodiment is described below:

[0067] This implementation method takes a 100-unit aggregated 1.5MW doubly-fed wind power plant as an example for simulation study. The system parameters of the doubly-fed wind turbine units are shown in Table 1. At t=80s, a 50MW load is introduced into the system to simulate the occurrence of frequency events in the system.

[0068] To further illustrate the control effect of the new energy power generation inertia phase-locked loop control method with fast frequency response proposed in this invention, a specific embodiment is described below:

[0069] This implementation method takes a 100-unit aggregated 1.5MW doubly-fed wind power plant as an example for simulation study. The system parameters of the doubly-fed wind turbine units are shown in Table 1. At t=80s, a 50MW load is introduced into the system to simulate the occurrence of frequency events in the system.

[0070] Table 1

[0071] Rated power <![CDATA[P sN ]]> 1.5MW Rated stator voltage <![CDATA[U sN ]]> 690V Rated power grid frequency <![CDATA[f sN ]]> 50Hz Extreme logarithm <![CDATA[p sN ]]> 2 pairs of poles Stator-rotor ratio <![CDATA[n sr ]]> 1∶2.5 Stator resistance <![CDATA[R s ]]> 0.023 pu stator leakage <![CDATA[L ls ]]> 0.18pu Rotor resistance <![CDATA[R r ]]> 0.016pu Rotor side leakage inductance <![CDATA[L lr ]]> 0.16pu Mutual induction <![CDATA[L m ]]> 2.9 Rated DC bus voltage <![CDATA[U dc ]]> 1200V wind speed V 10m / s

[0072] Specifically, the phase-locked loop structure and parameter settings for each scenario in the embodiment are as follows:

[0073] Scenario I: Typical fast phase-locked loop, proportional coefficient K p =60, integral coefficient K i =1400 (Bandwidth BW) PLL =13.42Hz);

[0074] Scenario II: Typical slow phase-locked loop, proportional coefficient K p =1.67, integral coefficient K i =1.4 (bandwidth BW) PLL =0.40Hz);

[0075] Scenario III: Novel Phase-Locked Loop, Proportional Coefficient Kp =60, integral coefficient K i =1400, phase compensation coefficient K=500 (bandwidth BW) PLL =0.40Hz);

[0076] Figure 6(a) shows the active power output waveform of the doubly-fed induction generator (DFIG), and Figure 6(b) shows the system frequency waveform. As can be seen from Figures 6(a) and 6(b), when the system frequency drops, in Scenario I, when the DFIG uses a typical phase-locked loop (PLL), the system's active power output remains almost unchanged under fast PLL parameters. In Scenario II, when using slow PLL parameters, although the DFIG's active power output is increased, the support time is short, resulting in weak support for the lowest frequency point. In Scenario III, using the new energy power generation inertia phase-locked loop control method with fast frequency response provided by this invention, with the same PLL bandwidth as in Scenario II, it provides strong and long-lasting support for the system frequency, significantly improving the lowest frequency point. Therefore, compared with a typical PLL, this invention can, to some extent, balance the contradiction between fast phase-locking and strong frequency support.

[0077] In summary, compared with the prior art, the present invention has the following advantages:

[0078] This invention provides a method and system for inertia-based phase-locked loop (PLL) control of new energy power generation with rapid frequency response. A phase delay element is added to the traditional PLL structure, improving the PLL's damping ratio and enabling the PLL to output a phase that lags behind the grid phase near the system's oscillation frequency. Furthermore, the amplitude-frequency response of the PLL's output phase angle is consistently at or below 0 dB, decreasing with increasing system oscillation frequency. In other words, the faster the grid frequency drops, the smaller the ratio of the amplitude of the PLL's output phase angle change to the amplitude of the grid phase angle change. This invention's rapid-frequency-response PLL control method for new energy power generation allows for dynamic fluctuations between the control and actual coordinate systems of new energy power generation equipment such as wind turbines during grid frequency faults, thus providing the new energy equipment with inertia response capabilities to withstand grid frequency drops.

[0079] This invention provides a new energy power generation inertia phase-locked loop control method and system with fast frequency response. When the phase-locked loop bandwidth is the same, it has a greater frequency support capability than the traditional phase-locked loop structure; conversely, when the frequency support capability is the same, it has a faster phase-locked loop bandwidth. Therefore, the new energy power generation inertia phase-locked loop control method with fast frequency response provided by this invention is more conducive to balancing the contradiction between frequency support capability and fast phase-locking.

[0080] This invention provides a method and system for controlling the inertia phase-locked loop of new energy power generation with fast frequency response. It retains the traditional vector control structure of existing new energy generator sets and only makes simple modifications to the control structure of the phase-locked loop. It has strong versatility and can be applied to various new energy power generation equipment connected to the grid via power electronics, such as doubly-fed wind turbines, direct-drive wind turbines, and photovoltaic power generation.

[0081] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A new energy power generation inertia phase-locked loop control system with fast frequency response, characterized in that, include: A phase detector, a phase delay unit, a loop filter, and a voltage-controlled oscillator are connected in sequence. The phase detector is used to receive the three-phase AC voltage signal at the grid connection point of the new energy power generation system, and to perform coordinate transformation on the three-phase AC voltage signal to a two-phase rotating coordinate system to obtain the q-axis component of the grid connection point voltage. The phase delay unit is used to delay the operation of the new energy power generation system after a frequency fault occurs. Phase compensation and amplitude attenuation are applied to the q-axis component of the grid-connected voltage, thereby increasing the phase difference between the phase angle of the phase-locked loop output and the stator voltage. This results in a larger power angle between the internal electromotive force and the stator voltage in the new energy power generation system, increasing the active power of the system and supporting the frequency drop of the system. K For phase compensation coefficients, s It is the Laplace operator; The loop filter is used to obtain the frequency deviation signal between the phase-locked loop angular frequency and the grid connection point voltage angular frequency; The voltage-controlled oscillator is used to analyze the frequency deviation signal between the phase-locked loop angular frequency and the grid connection point voltage angular frequency. The phase angle of the phase-locked loop is obtained by integration and used in the coordinate transformation stage of the control of new energy power generation system.

2. The new energy power generation inertia phase-locked loop control system according to claim 1, characterized in that, The loop filter is a PI controller. or low-pass filter ; in, K p This is the proportionality coefficient. K i The integral coefficient is... It is a time constant; s It is the Laplace operator.

3. The new energy power generation inertia phase-locked control system according to claim 1 or 2, characterized in that, The new energy power generation system includes: doubly fed wind turbines, direct-drive wind turbines, and photovoltaic power generation equipment.

4. The new energy power generation inertia phase-locked loop control system according to claim 3, characterized in that, When the new energy power generation system is a doubly-fed wind turbine, the active power of the doubly-fed wind turbine during the dynamic process is: in, E Internal potential; U s Stator voltage; X s For stator reactance; δ Internal potential E With stator voltage U s The angle between them; θ ctrl Internal potential E The included angle in the phase-locked coordinate system; θ s and θ pll These are the stator terminal voltage phase angle and the phase-locked loop output phase angle, respectively.

5. The new energy power generation inertia phase-locked control system according to claim 1 or 4, characterized in that, The q-axis voltage component at the grid connection point is: in, This is the voltage signal at the grid connection point; This represents the q-axis voltage component at the grid connection point.

6. A method for controlling the inertia of new energy power generation with fast frequency response, characterized in that, Includes the following steps: A phase detector is used to receive the three-phase AC voltage signal at the grid connection point of the new energy power generation system, and the coordinate transformation of the three-phase AC voltage signal is performed to a two-phase rotating coordinate system to obtain the q-axis component of the grid connection point voltage. After a frequency fault occurs in a new energy power generation system, the q-axis component of the grid connection point voltage is decelerated through a phase delay element. Phase compensation is performed to increase the phase difference between the phase angle of the phase-locked loop output and the phase angle of the stator voltage. This increases the power angle between the internal electromotive force and the stator voltage in the new energy power generation system, thereby increasing the active power of the system and supporting the frequency drop of the system. K For phase compensation coefficients, s It is the Laplace operator; A loop filter is used to obtain the frequency deviation signal between the phase-locked loop angular frequency and the grid connection point voltage angular frequency; A voltage-controlled oscillator is used to analyze the frequency deviation signal between the phase-locked loop angular frequency and the grid connection point voltage angular frequency. The phase angle of the phase-locked loop is obtained by integration and used in the coordinate transformation stage of the control of new energy power generation system.

7. The new energy power generation inertia phase-locked loop control method according to claim 6, characterized in that, The loop filter is a PI controller. or low-pass filter ; in, K p This is the proportionality coefficient. K i The integral coefficient is... It is a time constant; s It is the Laplace operator.

8. The new energy power generation inertia phase-locked control method according to claim 6 or 7, characterized in that, The new energy power generation system includes doubly-fed wind turbines, direct-drive wind turbines, and photovoltaic power generation equipment.

9. The new energy power generation inertia phase-locked loop control method according to claim 8, characterized in that, When the new energy power generation system is a doubly-fed wind turbine, the active power of the doubly-fed wind turbine during the dynamic process is: in, E Internal potential; U s Stator voltage; X s For stator reactance; δ Internal potential E With stator voltage U s The angle between them; θ ctrl Internal potential E The included angle in the phase-locked coordinate system; θ s and θ pll These are the stator terminal voltage phase angle and the phase-locked loop output phase angle, respectively.

10. The method for controlling the inertia of new energy power generation according to claim 6 or 9, characterized in that, The q-axis voltage component at the grid connection point is: in, This is the voltage signal at the grid connection point; This represents the q-axis voltage component at the grid connection point.

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