Adaptive control method and system for equivalent proportional integral coefficient of phase-locked loop controller

Abstract

The application discloses a kind of equivalent proportional integral coefficient self-adaptive control method and system of phase-locked loop controller, belong to new energy power system transient stability control field, method includes: the angle of detection new energy equipment grid-connected port, angular frequency and angular acceleration, wherein, new energy equipment and phase-locked loop controller are located in same new power system;According to angle, angular frequency, angular acceleration, preset coefficient and preset amplitude limiting value, proportional multiplication coefficient and integral multiplication coefficient are calculated;Proportional multiplication coefficient is multiplied by the inherent proportional coefficient of phase-locked loop controller, integral multiplication coefficient is multiplied by the inherent integral coefficient of phase-locked loop controller, to obtain equivalent proportional coefficient and equivalent integral coefficient, for phase-locked loop control.It can improve the transient stability maintenance capability of new energy equipment under serious fault condition, introduce multiplication link on existing structure, easy to realize.

Description

Technical Field

[0001] This invention belongs to the field of transient stability control of new energy power systems, and more specifically, relates to an adaptive control method and system for equivalent proportional-integral coefficients of a phase-locked loop controller. Background Technology

[0002] In recent years, new power systems based on new energy sources have developed rapidly, with wind and solar power systems showing particularly significant growth. The inherent low inertia and multi-timescale operation of new energy power generation present many challenges to transient stability mechanism analysis and stability enhancement. The transient stability of power systems involving power electronic devices requires further research.

[0003] The control loops of new power systems are complex, exhibiting multi-timescale actions and responses, which differ significantly from the operation and control methods of traditional synchronous machines. Grid connection of new energy equipment also frequently utilizes converter stages for power conversion, with phase-locked loops (PLLs) often used in the synchronization process. Their synchronization mechanisms differ from those of traditional synchronous generators, and the definitions of inertia and damping coefficients also present new characteristics. The transient stability problem of new power systems remains a key research focus, presenting numerous challenges in both theoretical and practical engineering applications.

[0004] Currently, transient stability enhancement control mainly falls into two categories. The first category involves modifying the traditional phase-locked loop (PLL) structure by introducing control loops or altering the PLL's control parameters to enhance system transient stability. The second category adjusts the reference values ​​of injected active current or active power during transient processes. For both of these control methods, there is a lack of adaptive adjustment control strategies for the equivalent proportional-integral (PI) coefficients of the PLL controller, developed through nonlinear analysis combining the equivalent rotor motion equations of the converter and studying the damping and inertia coefficients. Related implementation methods still do not fully utilize the influence of inertia and damping coefficients on transient stability, or the control loop settings are difficult to understand, analyze, and implement, thus hindering efficient and rapid transient stability control. Summary of the Invention

[0005] To address the shortcomings and improvement needs of existing technologies, this invention provides an adaptive control method and system for equivalent proportional-integral coefficients of a phase-locked loop controller. Its purpose is to improve the synchronous and stable operation capability of new energy power generation equipment when a serious fault occurs in the grid-connected system, and the implementation method is simple and efficient.

[0006] To achieve the above objectives, according to one aspect of the present invention, an adaptive control method for equivalent proportional-integral coefficients of a phase-locked loop (PLL) controller is provided, comprising: S1, detecting the angle, angular frequency, and angular acceleration of the grid-connected port of a new energy device, wherein the new energy device and the PLL controller are located in the same new power system; S2, calculating a proportional multiplication coefficient and an integral multiplication coefficient based on the angle, the angular frequency, the angular acceleration, a preset coefficient, and a preset limit value; S3, multiplying the proportional multiplication coefficient by the inherent proportional coefficient of the PLL controller, and multiplying the integral multiplication coefficient by the inherent integral coefficient of the PLL controller to obtain an equivalent proportional coefficient and an equivalent integral coefficient for use in PLL control.

[0007] Furthermore, the preset coefficient includes a first preset coefficient and a second preset coefficient, and S2 includes: determining the proportional multiplication coefficient based on the first product and the preset amplitude limit value, wherein the first product is the product of the angular frequency, the angular acceleration and the first preset coefficient; and determining the integral multiplication coefficient based on the second product and the proportional multiplication coefficient, wherein the second product is the product between the cosine value of the angle and the second preset coefficient.

[0008] Furthermore, the proportional multiplier is:

[0009]

[0010] Where, k i ' is the proportional multiplication factor, β is the preset amplitude limit value, λ1 is the first preset coefficient, ω is the angular frequency, and t is time. Let be the angular acceleration.

[0011] Furthermore, the integral multiplication factor is:

[0012] k p '=k i '(1+λ2cosδ)

[0013] Where, k p ' is the integral multiplication factor, k i ' is the proportional multiplication factor, λ2 is the second preset factor, and δ is the angle.

[0014] Furthermore, the second preset coefficient is no greater than 1.

[0015] Furthermore, the method also includes: the phase-locked loop controller using the equivalent proportional coefficient and the equivalent integral coefficient to perform synchronous control on the converter in the novel power system.

[0016] According to another aspect of the present invention, an adaptive control system for equivalent proportional-integral coefficients of a phase-locked loop (PLL) controller is provided, comprising: a detection module for detecting the angle, angular frequency, and angular acceleration of the grid-connected port of a new energy device, wherein the new energy device and the PLL controller are located in the same new power system; a multiplication factor calculation module for calculating a proportional multiplication factor and an integral multiplication factor based on the angle, the angular frequency, the angular acceleration, a preset coefficient, and a preset limit value; and an adaptive control module for multiplying the proportional multiplication factor by the inherent proportional coefficient of the PLL controller and multiplying the integral multiplication factor by the inherent integral coefficient of the PLL controller to obtain an equivalent proportional coefficient and an equivalent integral coefficient for use in PLL control.

[0017] In summary, the above-described technical solutions of this invention achieve the following beneficial effects: Based on the analysis of the equivalent damping coefficient and inertia coefficient of new energy sources, an adaptive control method for the equivalent proportional-integral coefficient of a phase-locked loop (PLL) controller is proposed. This method adaptively controls the equivalent proportional-integral coefficient of the PLL controller according to the angle, angular frequency, and angular acceleration of the grid-connected port of the new energy equipment. This improves the transient stability of the new energy power generation system when voltage dips occur, which is beneficial for the synchronous operation of the network and prevents the new energy power generation equipment from losing transient stability when a fault occurs. Furthermore, this method only requires the introduction of a multiplicative element generated through calculation into the original PLL controller, making the modification convenient and easy to implement. Attached Figure Description

[0018] Figure 1 A flowchart of the equivalent proportional-integral coefficient adaptive control method for a phase-locked loop controller provided in an embodiment of the present invention;

[0019] Figure 2 This is a control block diagram of the equivalent proportional-integral coefficient adaptive control method for a phase-locked loop controller provided in an embodiment of the present invention;

[0020] Figure 3 A comparison diagram of the stability domain boundaries when controlled by the equivalent proportional-integral coefficients and the inherent proportional-integral coefficients of the phase-locked loop controller generated by the method provided in the embodiments of the present invention.

[0021] Figure 4 A comparison diagram of the transient process trajectories on the phase diagram when control is performed using the equivalent proportional-integral coefficients generated by the method provided in the embodiments of the present invention and the inherent proportional-integral coefficients of the phase-locked loop controller, respectively;

[0022] Figure 5 Comparison of transient process time-domain response waveforms when controlled by the equivalent proportional-integral coefficients and the inherent proportional-integral coefficients of the phase-locked loop controller generated by the method provided in the embodiments of the present invention;

[0023] Figure 6 This is a block diagram of an equivalent proportional-integral coefficient adaptive control system for a phase-locked loop controller provided in an embodiment of the present invention. Detailed Implementation

[0024] 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. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0025] In this invention, the terms "first," "second," etc. (if present) in the invention and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0026] Figure 1 A flowchart illustrating the equivalent proportional-integral coefficient adaptive control method for a phase-locked loop controller provided in this embodiment of the invention. (See also...) Figure 1 , combined Figures 2-5 The adaptive control method of the equivalent proportional-integral coefficient of the phase-locked loop controller in this embodiment is described in detail. The method includes operations S1-S3.

[0027] Operation S1 detects the angle, angular frequency, and angular acceleration of the grid-connected port of the new energy equipment, where the new energy equipment and the phase-locked loop controller are located in the same new power system.

[0028] By detecting the parameters at the grid connection port of the new energy equipment, specifically the angle δ, angular frequency ω, and angular acceleration. Thus, key parameters for grid-connected operation transient stability analysis and control strategy formulation are obtained.

[0029] Operation S2 calculates the proportional multiplication factor and integral multiplication factor based on the angle, angular frequency, angular acceleration, preset coefficient, and preset amplitude limit.

[0030] Based on the detected angle δ, angular frequency ω, and angular acceleration of the grid connection port of the new energy equipment The parameters, combined with the pre-designed preset coefficients and preset limit values, are used to calculate and generate multiplication coefficients for the proportional-integral coefficient adjustment of the phase-locked loop controller. The multiplication coefficients include proportional multiplication coefficients and integral multiplication coefficients.

[0031] According to an embodiment of the present invention, the preset coefficient includes a first preset coefficient and a second preset coefficient. Operation S2 includes: determining a proportional multiplication coefficient based on a first product and a preset amplitude limit value, wherein the first product is the product of angular frequency, angular acceleration and the first preset coefficient; and determining an integral multiplication coefficient based on a second product and a proportional multiplication coefficient, wherein the second product is the product between the cosine value of the angle and the second preset coefficient.

[0032] According to an embodiment of the present invention, the proportional multiplication factor is:

[0033]

[0034] Where, k i ' is the proportional multiplier, β is the preset amplitude limit, λ1 is the first preset coefficient, ω is the angular frequency, and t is the time. ω is angular acceleration.

[0035] According to an embodiment of the present invention, the integral multiplication factor is:

[0036] k p '=k i '(1+λ2cosδ)

[0037] Where, k p ' is the integral multiplication factor, k i ' is the proportional multiplication factor, λ2 is the second preset factor, and δ is the angle.

[0038] In the multiplication factor generation stage, λ1, λ2, and β can be flexibly set as needed. A larger λ1 is more conducive to better utilizing the effectiveness of the control method. Preferably, the second preset coefficient λ2 is no greater than 1 to prevent the final equivalent proportional coefficient and equivalent integral coefficient from having negative values. β, as a limiting value, can be flexibly selected.

[0039] Operation S3 multiplies the proportional multiplier with the inherent proportional coefficient of the phase-locked loop controller and multiplies the integral multiplier with the inherent integral coefficient of the phase-locked loop controller to obtain the equivalent proportional coefficient and equivalent integral coefficient, which are then used for phase-locked loop control.

[0040] An adaptive adjustment strategy for the equivalent proportional-integral coefficient of the final phase-locked loop (PLL) controller is implemented by introducing additional branches, thereby changing the overall external performance parameters of the PLL. Ultimately, the external equivalent proportional coefficient k of the PLL controller... i and equivalent integral coefficient k p They are respectively:

[0041] k i =k i0 k i '

[0042] k p =kp0 k p '

[0043] According to an embodiment of the present invention, the method further includes: a phase-locked loop controller using an equivalent proportional coefficient and an equivalent integral coefficient to perform synchronous control on a converter in a novel power system. Specifically, the phase-locked loop controller uses an equivalent proportional coefficient k i and equivalent integral coefficient k p The data at the input of the phase-locked loop (PLL) PI controller is subjected to proportional-integral control, and the result is output through the output of the PLL PI controller, such as... Figure 2 As shown.

[0044] This invention employs an infinite bus voltage drop fault to test the effectiveness of the equivalent proportional-integral coefficient adaptive control method (hereinafter referred to as the adaptive control method) of the phase-locked loop controller. It is assumed that the bus voltage drops from the pre-fault setpoint of 0.4 pu to 0.25 pu, and finally recovers to 0.38 pu after the fault is cleared in 0.06 seconds. The stability region, phase diagram trajectory, and time-domain waveform before and after using the adaptive control method are compared to verify its effectiveness.

[0045] See Figure 3 As can be seen, after adopting this adaptive control method, the stability region increases, which is beneficial for the converter equipment to maintain transient stability. (See also...) Figure 4 As can be seen, after adopting this adaptive control method, the motion trajectory on the phase diagram is closer to the equilibrium point, and the range is reduced. (See also...) Figure 5 As can be seen, after adopting this adaptive control method, the oscillation degree of the power angle curve in the time domain is reduced, and it tends to stabilize more quickly. Overall, this adaptive control method has an enhancing effect on transient processes.

[0046] In summary, the phase-locked loop controller equivalent proportional-integral coefficient adaptive control method provided in this embodiment of the invention can improve the synchronous operation capability of new energy power generation equipment and the power grid when the grid voltage drops, and can also increase the system stability domain range, reduce the degree of time-domain waveform oscillation, so that the phase diagram trajectory is closer to the stable equilibrium point, which is beneficial to transient stability.

[0047] Figure 6 This is a block diagram of an equivalent proportional-integral coefficient adaptive control system for a phase-locked loop controller provided in an embodiment of the present invention. (See also...) Figure 6 The phase-locked loop controller equivalent proportional-integral coefficient adaptive control system 600 includes a detection module 610, a multiplication coefficient calculation module 620, and an adaptive control module 630.

[0048] The detection module 610, for example, performs operation S1 to detect the angle, angular frequency and angular acceleration of the grid-connected port of the new energy equipment, wherein the new energy equipment and the phase-locked loop controller are located in the same new power system.

[0049] The multiplier calculation module 620, for example, performs operation S2 to calculate the proportional multiplier and integral multiplier based on the angle, angular frequency, angular acceleration, preset coefficient, and preset amplitude limit.

[0050] The adaptive control module 630, for example, performs operation S3 to multiply the proportional multiplier by the inherent proportional coefficient of the phase-locked loop controller and multiply the integral multiplier by the inherent integral coefficient of the phase-locked loop controller to obtain the equivalent proportional coefficient and equivalent integral coefficient for use in phase-locked loop control.

[0051] The phase-locked loop controller equivalent proportional-integral coefficient adaptive control system 600 is used to execute the above. Figures 1-5 The phase-locked loop controller in the illustrated embodiment is an equivalent proportional-integral coefficient adaptive control method. For details not covered in this embodiment, please refer to the foregoing... Figures 1-5 The equivalent proportional-integral coefficient adaptive control method of the phase-locked loop controller in the illustrated embodiment will not be described in detail here.

[0052] 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 phase-locked loop controller with equivalent proportional-integral coefficient adaptive control method, characterized in that, include: S1, detect the angle, angular frequency and angular acceleration of the grid connection port of the new energy equipment, wherein the new energy equipment and the phase-locked loop controller are located in the same new power system; S2, calculate the proportional multiplication factor and the integral multiplication factor based on the angle, the angular frequency, the angular acceleration, the preset coefficient and the preset amplitude limit; S3, multiply the proportional multiplier coefficient by the inherent proportional coefficient of the phase-locked loop controller, and multiply the integral multiplier coefficient by the inherent integral coefficient of the phase-locked loop controller to obtain the equivalent proportional coefficient and the equivalent integral coefficient, which are used for phase-locked loop control; The preset coefficients include a first preset coefficient and a second preset coefficient. S2 includes: determining the proportional multiplication coefficient based on the first product and the preset amplitude limit value, wherein the first product is the product of the angular frequency, the angular acceleration and the first preset coefficient; and determining the integral multiplication coefficient based on the second product and the proportional multiplication coefficient, wherein the second product is the product between the cosine value of the angle and the second preset coefficient. The proportional multiplier is: ; The ratio multiplier is the coefficient mentioned above. The preset amplitude limit value, The first preset coefficient, The angular frequency is... For time, The angular acceleration is mentioned above; The integral multiplication factor is: ; The integral multiplication factor is the coefficient. The ratio multiplier is the coefficient mentioned above. This is the second preset coefficient. The angle is described above.

2. The adaptive control method for equivalent proportional-integral coefficients of a phase-locked loop controller as described in claim 1, characterized in that, The second preset coefficient is no greater than 1.

3. The adaptive control method for equivalent proportional-integral coefficients of a phase-locked loop controller as described in claim 1, characterized in that, The method also includes: The phase-locked loop controller uses the equivalent proportional coefficient and the equivalent integral coefficient to perform synchronous control on the converter in the new power system.

4. A phase-locked loop controller equivalent proportional-integral coefficient adaptive control system, characterized in that, The method for executing the equivalent proportional-integral coefficient adaptive control method of the phase-locked loop controller as described in claim 1 includes: The detection module is used to detect the angle, angular frequency and angular acceleration of the grid connection port of the new energy equipment, wherein the new energy equipment and the phase-locked loop controller are located in the same new power system; The multiplication factor calculation module is used to calculate the proportional multiplication factor and the integral multiplication factor based on the angle, the angular frequency, the angular acceleration, the preset coefficient, and the preset amplitude limit. An adaptive control module is used to multiply the proportional multiplier by the inherent proportional coefficient of the phase-locked loop controller and multiply the integral multiplier by the inherent integral coefficient of the phase-locked loop controller to obtain an equivalent proportional coefficient and an equivalent integral coefficient for use in phase-locked loop control.

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