Voltage stabilization and line loss cooperative control method and device, equipment and storage medium

Abstract

The invention provides a voltage stabilization and line loss cooperative control method, device and equipment and a storage medium, and the method comprises the steps: according to the comparison of a power grid voltage amplitude and a key load voltage reference value amplitude, when the power grid voltage is smaller than a reference value, the minimum current amplitude is the radius difference of two circles; when the difference is larger than the reference value, the difference is the distance between two circle centers and the radius, and the minimum transmission line current amplitude is calculated through a geometrical relationship. And deriving a real part and an imaginary part of the current of the transmission line based on the minimum amplitude, and further calculating an output voltage reference value of the power spring. An output voltage reference value is decomposed into an amplitude value and a phase reference value, a modulation signal is generated through a proportional resonance controller and compared with a carrier signal, and a PWM signal is generated to control a power spring switching device. Through the geometric analysis, on the premise of considering the ES active compensation limit, the transmission line current is minimized, the active loss is remarkably reduced, and the energy efficiency and robustness of the system are improved while the key load voltage is accurate and stable.

Description

Technical Field

[0001] This application belongs to the field of power grid control, and in particular relates to a method, device, equipment and storage medium for coordinated control of voltage stabilization and line loss. Background Technology

[0002] Electric springs (ES) are mainly used in grid-connected systems with a high proportion of renewable energy to stabilize the voltage of critical loads, solve the problem of grid voltage fluctuations caused by the intermittency and unpredictability of renewable energy sources such as wind and solar power, and ensure the safe operation of voltage-sensitive loads.

[0003] Electric spring technology classifies loads into critical loads (CL) and non-critical loads (NCL), and connects the inverter output voltage (ES) in series with the NCL to form a smart load branch. The ES injects or absorbs active and reactive power into the system by adjusting the amplitude and phase of its inverter output voltage, thereby compensating for grid voltage fluctuations and stabilizing the CL voltage at the reference value. This method achieves rapid support and oscillation suppression of the CL voltage through bidirectional power regulation.

[0004] During the process of stabilizing the CL voltage, the existing power spring control strategy ignores the transmission line impedance Z. L With ES active power compensation limit P ES The coupling effect. Due to P ES Strict boundaries exist, and Z is not considered. L The impact of this can prevent traditional methods from optimizing the current amplitude of transmission lines. When the grid voltage fluctuates drastically, overcompensation or undercompensation may occur. At the same time, the active power loss of transmission lines is high, which restricts the value of engineering applications. Summary of the Invention

[0005] The purpose of this application is to overcome the deficiencies in the prior art and provide a method, apparatus, device and storage medium for coordinated control of voltage stabilization and line loss.

[0006] This application provides a method for coordinated control of voltage stabilization and line loss, including:

[0007] Based on the grid voltage and critical load voltage reference values, the minimum transmission line current amplitude is calculated through geometric analysis. This geometric analysis includes: comparing the amplitude of the grid voltage with the amplitude of the critical load voltage reference value, distinguishing between two cases: when the amplitude of the grid voltage is less than the amplitude of the critical load voltage reference value, the minimum transmission line current amplitude is calculated as a first difference using a first geometric relationship, where the first difference is the difference between the radius parameter and the distance between the centers of the two circles represented by the first geometric relationship; when the amplitude of the grid voltage is greater than the amplitude of the critical load voltage reference value, the minimum transmission line current amplitude is calculated as a second difference using a second geometric relationship, where the second difference is the difference between the distance between the centers of the two circles represented by the second geometric relationship and the radius parameter.

[0008] Based on the minimum transmission line current amplitude, calculate the corresponding real part and imaginary part of the transmission line current;

[0009] Calculate the reference value of the power spring output voltage based on the real part of the transmission line current, the imaginary part of the transmission line current, and the grid voltage.

[0010] The output voltage reference value of the electric spring is decomposed into an amplitude reference value and a phase reference value;

[0011] A proportional resonant controller is used to generate a modulation signal based on the amplitude reference value and the phase reference value;

[0012] The modulated signal is compared with the carrier signal to generate a pulse width modulation signal to control the switching device of the electric spring.

[0013] Optionally, based on reference values ​​for grid voltage and critical load voltage, the minimum transmission line current amplitude is calculated through geometric analysis, including:

[0014] In the geometric analysis, circular equation constraints for the transmission line current are established;

[0015] The circle equation constraint states that the square of the difference between the real part of the transmission line current and the first circle center parameter, plus the square of the difference between the imaginary part of the transmission line current and the second circle center parameter, equals the square of the radius parameter.

[0016] Optionally, based on reference values ​​for grid voltage and critical load voltage, the minimum transmission line current amplitude is calculated through geometric analysis, including:

[0017] Calculate the parameters of the first circle center;

[0018] The first center parameter is the cosine of the ratio of the grid voltage amplitude to the transmission line impedance magnitude multiplied by the difference between the grid voltage phase angle and the transmission line impedance angle.

[0019] Optionally, based on reference values ​​for grid voltage and critical load voltage, the minimum transmission line current amplitude is calculated through geometric analysis, including:

[0020] Calculate the second center parameter;

[0021] The second center parameter is the sine value of the ratio of the grid voltage amplitude to the transmission line impedance magnitude multiplied by the difference between the grid voltage phase angle and the transmission line impedance angle.

[0022] Optionally, based on reference values ​​for grid voltage and critical load voltage, the minimum transmission line current amplitude is calculated through geometric analysis, including:

[0023] Calculate the radius parameter;

[0024] The radius parameter is the ratio of the magnitude of the critical load voltage reference value to the magnitude of the transmission line impedance.

[0025] Optionally, based on reference values ​​for grid voltage and critical load voltage, the minimum transmission line current amplitude is calculated through geometric analysis, including:

[0026] Calculate the distance between the centers of the two circles;

[0027] The distance between the two centers is the square root of the sum of the squares of the first center parameter and the second center parameter.

[0028] Optionally, based on the minimum transmission line current amplitude, the corresponding real part and imaginary part of the transmission line current are calculated, including:

[0029] Calculate the real part of the transmission line current;

[0030] The real part of the transmission line current is the product of the first center parameter and the difference between the distance between the two centers and the radius parameter, divided by the distance between the two centers.

[0031] Calculate the imaginary part of the transmission line current;

[0032] The imaginary part of the transmission line current is the product of the second center parameter, the radius parameter, and the difference in distance between the two centers, divided by the distance between the two centers.

[0033] This application also provides a voltage stabilization and line loss coordinated control device, including:

[0034] The analysis module calculates the minimum transmission line current amplitude based on the grid voltage and critical load voltage reference values ​​through geometric analysis. This geometric analysis includes: based on a comparison between the grid voltage amplitude and the critical load voltage reference value, distinguishing between two cases: when the grid voltage amplitude is less than the critical load voltage reference value, the minimum transmission line current amplitude is calculated as a first difference using a first geometric relationship, where the first difference is the difference between the radius parameter and the distance between the centers of the two circles represented by the first geometric relationship; when the grid voltage amplitude is greater than the critical load voltage reference value, the minimum transmission line current amplitude is calculated as a second difference using a second geometric relationship, where the second difference is the difference between the distance between the centers of the two circles represented by the second geometric relationship and the radius parameter.

[0035] The amplitude module calculates the real part and imaginary part of the transmission line current based on the minimum transmission line current amplitude.

[0036] The voltage module calculates the reference value of the power spring output voltage based on the real part of the transmission line current, the imaginary part of the transmission line current, and the grid voltage.

[0037] The reference module decomposes the output voltage reference value of the electric spring into an amplitude reference value and a phase reference value;

[0038] The signal module uses a proportional resonant controller to generate a modulation signal based on the amplitude reference value and the phase reference value;

[0039] The control module compares the modulation signal with the carrier signal to generate a pulse width modulation signal to control the switching device of the electric spring.

[0040] This application also provides an electronic device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the method described above.

[0041] This application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed in a computer, causes the computer to perform the above-described method.

[0042] The beneficial effects of this application are:

[0043] This application provides a method for coordinated control of voltage stabilization and line loss, comprising: calculating the minimum transmission line current amplitude through geometric analysis based on the grid voltage and a critical load voltage reference value; the geometric analysis comprising: distinguishing two cases based on a comparison between the amplitude of the grid voltage and the amplitude of the critical load voltage reference value; when the amplitude of the grid voltage is less than the amplitude of the critical load voltage reference value, calculating the minimum transmission line current amplitude as a first difference through a first geometric relationship, wherein the first difference is the difference between the radius parameter and the distance between the centers of the two circles represented by the first geometric relationship; when the amplitude of the grid voltage is greater than the amplitude of the critical load voltage reference value, calculating the minimum transmission line current amplitude as a first difference through a second geometric relationship. The minimum transmission line current amplitude is the second difference, which is the difference between the distance between the centers of the two circles represented by the second geometric relationship and the radius parameter. Based on the minimum transmission line current amplitude, the corresponding real and imaginary parts of the transmission line current are calculated. Based on the real and imaginary parts of the transmission line current and the grid voltage, a reference value for the power spring output voltage is calculated. This reference value is decomposed into an amplitude reference value and a phase reference value. Using a proportional resonant controller, a modulation signal is generated based on the amplitude and phase reference values. The modulation signal is compared with a carrier signal to generate a pulse width modulation signal to control the switching devices of the power spring. This application calculates the minimum transmission line current amplitude through geometric analysis and considers the ES active power compensation limit, achieving a significant reduction in transmission line active power loss while stabilizing the critical load voltage, thus improving system energy efficiency and robustness. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the coordinated control process for voltage stabilization and line loss in this application;

[0045] Figure 2 This application contains a schematic diagram of the single-phase ES-2 system structure;

[0046] Figure 3 This is a schematic diagram of the geometric relationship between the two circles involved in this application;

[0047] Figure 4 This is a schematic diagram of the power spring control strategy based on transmission line current in this application;

[0048] Figure 5 This is a schematic diagram of the circuit simulation parameters in this application;

[0049] Figure 6 This is a schematic diagram comparing the effective values ​​of key load voltages in this application;

[0050] Figure 7 This is a schematic diagram of the effective value of the transmission line current in this application. Detailed Implementation

[0051] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it is to be understood that various forms of implementation of the present disclosure are intended and should not be limited to the embodiments set forth herein. Rather, the embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0052] Please refer to Figure 1 This application provides a voltage stabilization and line loss coordinated control method, applied in the field of renewable energy grid-connected systems, to solve the problems of wasted DC-side energy storage capacity and control failure caused by the neglect of active power compensation range limitations in existing power spring technology, and the increased distribution network losses caused by the unoptimized transmission line current amplitude. The method includes:

[0053] S101. Based on the reference values ​​of the grid voltage and the critical load voltage, calculate the minimum transmission line current amplitude through geometric analysis.

[0054] The geometric analysis includes: based on a comparison of the magnitude of the grid voltage and the magnitude of the critical load voltage reference value, distinguishing between two cases: when the magnitude of the grid voltage is less than the magnitude of the critical load voltage reference value, the minimum transmission line current magnitude is calculated as a first difference using a first geometric relationship, where the first difference is the difference between the radius parameter and the distance between the two centers represented by the first geometric relationship; when the magnitude of the grid voltage is greater than the magnitude of the critical load voltage reference value, the minimum transmission line current magnitude is calculated as a second difference using a second geometric relationship, where the second difference is the difference between the distance between the two centers represented by the second geometric relationship and the radius parameter.

[0055] like Figure 2 As shown, the geometric analysis of this application is based on Figure 2 The power grid structure shown, in which Figure 2 This is a typical diagram of a power system containing a single-phase ES-2, and the corresponding dashed box contains the ES-2 topology.

[0056] Where Z is the equivalent impedance of the transmission line. For critical loads, For non-critical loads, for one A bidirectional voltage source that can feed energy into and absorb energy from the system; precisely because of this bidirectional voltage source... The existence of Can be with The arbitrary phase difference allows the ES-2 to provide mixed compensation for active and reactive power, unlike the ES-1.

[0057] ES-2 is connected in series with a non-critical load to form a SmartLoad (SL); SL ​​is connected in parallel with a critical load to form the load of the PCC; R1 and L1 are the equivalent resistance and inductance of the transmission line, respectively; V G V is the mains voltage; s The voltage at PCC; To transmit current on the line; For critical load current; Non-critical load current; V ES This is the output voltage of the filter capacitor (i.e., the output voltage of ES-2). When V s Equal to the rated load voltage At this time, ES-2 will not function. When the load voltage is higher or lower than the rated value... At that time, ES-2 can provide a certain amount of power to the power system, making V s Equal to the rated load voltage This achieves the goal of stabilizing the load-side voltage. The electric spring should control the critical load voltage V. s Control to reference value At this time, the transmission line current must meet the following constraint, namely formula (1):

[0058]

[0059] in, Let the real part of the transmission line current be denoted as . This represents the imaginary part of the transmission line current. The parameter of the first circle center. The parameter for the second center of the circle. The parameter is the radius.

[0060] Formula (2) for calculating the first center parameter:

[0061]

[0062] in, The magnitude of the grid voltage. The magnitude of the equivalent impedance of the transmission line. The phase angle of the grid voltage. The impedance angle is the equivalent impedance of the transmission line.

[0063] Formula (3) for calculating the second center parameter:

[0064]

[0065] in, The magnitude of the grid voltage. The magnitude of the equivalent impedance of the transmission line. The phase angle of the grid voltage. The impedance angle is the equivalent impedance of the transmission line.

[0066] The radius parameter is calculated using formula (4):

[0067]

[0068] in, The amplitude of the critical load voltage reference value. This represents the magnitude of the equivalent impedance of the transmission line.

[0069] Analysis of the transmission line yields the complex power as shown in formula (5):

[0070]

[0071] in, For the complex power of the transmission line, The given value represents the real part of the transmission line current. This represents the imaginary part of the transmission line current. The magnitude of the equivalent impedance of the transmission line. The impedance angle is the equivalent impedance of the transmission line.

[0072] The active power consumed on the transmission line is given by formula (6):

[0073]

[0074] in, The active power consumed on the transmission line. Let the real part of the transmission line current be denoted as . This represents the imaginary part of the transmission line current. The magnitude of the equivalent impedance of the transmission line. The impedance angle is the equivalent impedance of the transmission line.

[0075] The amplitude of the transmission line current is given by formula (7):

[0076]

[0077] in, The amplitude of the transmission line current. Let the real part of the transmission line current be denoted as . This represents the imaginary part of the transmission line current.

[0078] Combining equations (6) and (7), it can be seen that the active power loss consumed on the transmission line can be controlled by adjusting the amplitude of the transmission line current.

[0079] To minimize active power loss, the amplitude of the transmission line current should also be minimized. Furthermore, because the power spring ES controls the critical load voltage V... s When the current reaches the rated value, the transmission line current must satisfy equation (1).

[0080] Squaring both sides of equation (7), we get equation (8):

[0081]

[0082] in, The amplitude of the transmission line current. Let the real part of the transmission line current be denoted as . This represents the imaginary part of the transmission line current.

[0083] Observing equation (8), it can be seen that it can be regarded as a circle with (0,0) as the center C1. A circle with radius . Where, as As the circle changes, its radius also changes.

[0084] Equation (1) can be viewed as a circle C2 with radius C2 and radius λ, centered at (K1, K2).

[0085] Therefore, the two circles must intersect. Plot equations (1) and (8) on a two-dimensional plane coordinate system. Since the center (0, 0) of equation (8) may be outside or inside the circle of equation (1), there are two cases, which can be obtained as follows: Figure 3 (a) and Figure 3 (b)

[0086] like Figure 3 As shown, the blue concentric circles represent the circles in equation (8) with center C1 at (0, 0) and radius I. M It equals r1 (radius represented by blue line segment) and r2 (radius represented by yellow line segment); the green circle represents (K1, K2) in equation (1), radius λ (radius represented by green line segment); d is the distance between the centers of the two circles ( Figure 3 The purple line represents (i.e., formula (9):

[0087]

[0088] Where K1 is the first center parameter and K2 is the second center parameter.

[0089] When the center (0, 0) of equation (8) is outside the circle of equation (1), according to Figure 3 (a) It can be seen that formula (10) is correct at this time:

[0090]

[0091] Where d is the distance between the centers of the two circles. This is the radius parameter.

[0092] According to equations (2) and (3), we can obtain formula (11):

[0093]

[0094] Where K1 is the first center parameter and K2 is the second center parameter. The magnitude of the grid voltage. This represents the magnitude of the equivalent impedance of the transmission line.

[0095] Substituting equation (11) into equation (9), and combining equations (4) and (10), we can obtain that when the center (0, 0) of equation (8) is outside the circle of equation (1), it means that equation (12) is:

[0096]

[0097] in, The magnitude of the grid voltage. This refers to the amplitude of the critical load voltage reference value.

[0098] In this case, according to Figure 3 From the geometric relationship in (a), we can see that the maximum value is obtained at the point of tangency between the two circles (marked by the red cross in the figure), and the electric spring transmits the line current amplitude I under the premise of stabilizing the critical load voltage. M minimum value For formula (13):

[0099]

[0100] in, This is the minimum transmission line current amplitude, specifically the value. .

[0101] Furthermore, based on the proportional allocation of line segments, it can be seen that when ES respectively obtains The working point of ES is in a two-dimensional coordinate system. The distribution in the middle is located in formula (14):

[0102]

[0103] in, Let the real part of the transmission line current be denoted as . This represents the imaginary part of the transmission line current. The distance between the centers of the two circles. For radius parameter, and As a proportional parameter, in practice , .

[0104] When the center (0, 0) of equation (8) is inside the circle of equation (1), according to Figure 3 (a) It can be seen that at this time, formula (15) is:

[0105]

[0106] in, The distance between the centers of the two circles. This is the radius parameter.

[0107] Substituting equation (11) into equation (9), and combining equations (4) and (15), we can obtain that when the center (0, 0) of equation (9) is inside the circle of equation (1), it means that equation (16) is:

[0108]

[0109] in, The magnitude of the grid voltage. This refers to the amplitude of the critical load voltage reference value.

[0110] In this case, according to Figure 3 From the geometric relationship in (b), we can see that I M The maximum value is obtained at the point of tangency between the two circles (marked by a red cross in the diagram), while the electric spring transmits the line current amplitude I under the premise of stabilizing the critical load voltage. M minimum value For formula (17):

[0111]

[0112] in, This is the minimum transmission line current amplitude. The distance between the centers of the two circles. This is the radius parameter.

[0113] Furthermore, based on the proportional allocation of line segments, it can be seen that when ES respectively obtains The working point of ES is in a two-dimensional coordinate system. The distribution in the middle is located in formula (18):

[0114]

[0115] in, Let the real part of the transmission line current be denoted as . This represents the imaginary part of the transmission line current. The distance between the centers of the two circles. For radius parameter, and As a proportional parameter, in practice , .

[0116] As can be seen from the above, the minimum value of the transmission line current amplitude of the electric spring under the premise of stable critical load can be obtained through analysis, and the corresponding value can be obtained according to equation (14) or equation (18). The compensation point is used to determine the value of the transmission line current.

[0117] Furthermore, the specific operational process of the geometric analysis involves establishing a geometric model on a two-dimensional plane composed of the real and imaginary parts of the transmission line current. First, a circular trajectory representing the voltage stability constraint is determined, which is based on the key load voltage reference value and system parameters. Then, a series of concentric circles representing different current amplitudes are constructed. By analyzing the relative positional relationship between these two circular trajectories, particularly the condition under which they are tangent, the optimal operating point that simultaneously satisfies the objectives of voltage stability and current minimization is precisely located. The analysis process involves determining the relative position of the two circles (internal or external tangency) and using the geometric properties of the circles to solve for the coordinates of the tangency point, thereby transforming the complex electrical constraint optimization problem into an intuitive geometric problem.

[0118] S102. Calculate the real part and imaginary part of the transmission line current based on the minimum transmission line current amplitude.

[0119] Real part of transmission line current and the imaginary part of the transmission line current The calculation is based on the results of geometric analysis.

[0120] When the minimum transmission line current amplitude is obtained, according to equation (14) or equation (18), the formula for calculating the real part of the transmission line current is equation (19):

[0121]

[0122] in, The parameter of the first circle center. The distance between the centers of the two circles. This is the radius parameter.

[0123] Imaginary part of transmission line current The calculation formula is formula (20):

[0124]

[0125] in, The parameter for the second center of the circle. The distance between the centers of the two circles. This is the radius parameter.

[0126] These calculation formulas are derived from the coordinate relationship of the tangent points of two circles in geometric analysis. They are obtained through the proportional allocation of line segments to ensure that the real and imaginary parts of the transmission line current correspond to the operating point with the minimum current amplitude.

[0127] The technique for calculating the real and imaginary parts of transmission line current is based on the optimal operating point coordinates determined by geometric analysis. By connecting the centers of two circles through the point of tangency, and utilizing the properties of tangents and the proportional relationships of line segments in plane geometry, the x and y coordinates of the point of tangency relative to the origin are accurately calculated. These two coordinate values ​​correspond to the real and imaginary parts of the transmission line current, respectively, ensuring that the obtained current components accurately achieve the preset minimum amplitude target.

[0128] S103. Calculate the reference value of the power spring output voltage based on the real part of the transmission line current, the imaginary part of the transmission line current, and the grid voltage;

[0129] The relationship between the transmission line current, the output voltage of the power spring, and the grid voltage is given by formula (21):

[0130]

[0131]

[0132]

[0133] in, To transmit line current, the real part is... and the virtual part synthesis, This is the grid voltage. and These are system parameters. For critical load impedance, For non-critical load impedance, This is the equivalent impedance of the transmission line.

[0134] According to equation (21), once the transmission line current... Determine and grid voltage If the voltage is collected, then the voltage compensated by the electric spring ES is... This is thus determined, thereby achieving the goal of control.

[0135] The technique for calculating the reference value of the power spring output voltage is based on the circuit network equations of a specific power grid topology. By establishing the relationship between the voltage of each node and the branch current in the system, intermediate variables are eliminated, and the functional relationship between the power spring output voltage, the grid voltage, and the transmission line current is derived. This relationship shows that for a given grid voltage and a desired transmission line current, there exists a unique corresponding power spring output voltage value, thus the required output voltage reference value can be directly calculated through this functional relationship.

[0136] S104. Decompose the power spring output voltage reference value into an amplitude reference value and a phase reference value;

[0137] The process of decomposing the power spring output voltage reference value into amplitude reference value and phase reference value is as follows.

[0138] according to The reference value of the ES output voltage amplitude can be obtained through equations (22) and (23). And the phase reference value of the ES output voltage, i.e., formulas (22) and (23):

[0139]

[0140]

[0141] in, This represents the real part of the reference value for the output voltage of the electric spring. This represents the imaginary part of the reference value for the output voltage of the electric spring.

[0142] The technique of decomposing the output voltage reference value of an electric spring into amplitude and phase reference values ​​is achieved through the conversion from rectangular coordinates to polar coordinates. This conversion process extracts the magnitude of the output voltage as the amplitude reference and calculates the argument of the output voltage as the phase reference, converting the complex form of the output voltage into amplitude and phase forms that are easy for the controller to process, thus providing a foundation for subsequent waveform synthesis and closed-loop control.

[0143] S105. Using a proportional resonant controller, a modulation signal is generated based on the amplitude reference value and the phase reference value;

[0144] The process of using a proportional resonant controller involves the third part of the entire control strategy.

[0145] Specifically, the error between the sinusoidal output voltage of the electric spring in the second part and the actual sinusoidal output voltage of the electric spring is proportionally resonantly controlled to obtain the final modulated wave signal. This modulated wave signal is then compared with the carrier signal to generate four pulse width modulation signals, which control the switching on and off of the switching transistor. For example... Figure 4 As shown in the blue box.

[0146] The technique of generating a modulated signal using a proportional-resonant controller involves two main processes: error detection and signal conditioning. First, the desired reference signal for the output voltage of the electric spring is compared with the actually detected output voltage signal to obtain an error signal. This error signal is then fed into the proportional-resonant controller. The proportional-resonant controller has extremely high gain for specific frequency signals, enabling precise tracking of the sinusoidal reference signal. The controller outputs a continuous control signal as the modulated signal, the waveform and amplitude of which reflect the control action required to eliminate the output voltage error.

[0147] S106. The modulation signal is compared with the carrier signal to generate a pulse width modulation signal to control the switching device of the electric spring.

[0148] The entire control strategy can be divided into three parts:

[0149] The first part is to find the minimum value of the transmission line current amplitude under a stable critical load voltage.

[0150] The second part is to obtain the output voltage of the electric spring ES that satisfies the control target based on the minimum value and in combination with equations (14) and (18), and decompose it into the reference value of the amplitude of the output voltage of the electric spring ES and the reference value of the phase of the output voltage of ES, so as to obtain the reference sinusoidal signal of the output voltage of ES.

[0151] The third part involves comparing the obtained ES output voltage reference sine wave with the actual ES output voltage sine wave, obtaining the modulation signal through a proportional resonant controller, and then comparing it with the carrier signal to generate the switching signal of the control device.

[0152] To verify the effectiveness of the proposed electric spring control strategy in simultaneously stabilizing critical load voltage and reducing transmission line current, based on Figure 4 The control strategy block diagram proposed in the paper is used to construct a simulation model for simulation verification. The simulation parameters are as follows: Figure 5 As shown.

[0153] To verify the effectiveness of the proposed control strategy, we analyzed three cases for the same set of power network parameters: no ES, ES-1, and ES-2.

[0154] Within the effective operating range of the electric spring, the grid voltage amplitude and amplitude were selected to simulate its fluctuation. The simulation results are as follows:

[0155] like Figure 6As shown by the solid red line in the figure, when the ES is not connected to the power grid, the effective voltage across the critical load does not stabilize to the reference value of around 220V, but is around 212.5V. However, after the power spring is activated, the voltage across the critical load side gradually stabilizes to 220V in both ES-1 (shown by the blue dashed line) and ES-2 (shown by the green dashed line).

[0156] Figure 6 (b) The grid voltage amplitude is 230V. As can be seen from the red solid line in the figure, when the ES is not connected to the grid system, the effective voltage value at both ends of the critical load does not stabilize to the reference value of 220V, but is about 225V.

[0157] After the electric spring is activated, the voltage across the critical load side gradually stabilizes to 220V in both cases, whether it is ES-1 (shown by the blue dashed line) or ES-2 (shown by the green dashed line).

[0158] This demonstrates that the control strategy proposed in this application is effective in stabilizing the voltage on the critical load side, regardless of whether the effective value of the critical load voltage is greater than or less than its reference value.

[0159] like Figure 7 As shown, Figure 7 (a) The grid voltage amplitude is 216V. As shown by the solid red line in the figure, when ES is not connected to the grid system, the effective value of the current amplitude on the transmission line is relatively large, around 24.7A. After ES1 is activated (shown by the dashed blue line), although the voltage across the critical load stabilizes to the target reference value of 220V, the effective value of the current amplitude on the transmission line does not decrease significantly, remaining at approximately 23.5A.

[0160] After ES-2 is activated (shown by the green dashed line), the effective voltage across the critical load side not only gradually stabilizes at 220V, but the effective current amplitude on the transmission line is significantly reduced to approximately 5.8A.

[0161] Figure 7 (b) The grid voltage amplitude is 230V. According to the red solid line in the figure, the current amplitude on the transmission line is relatively large at this time, with an effective value of about 27.6A.

[0162] After ES-1 is activated (shown by the blue dashed line), although the effective value of the voltage across the critical load stabilizes to the target reference value of 220V, the current amplitude on the transmission line does not decrease significantly, remaining at approximately 23.6A.

[0163] After ES-2 is activated (shown by the green dashed line), the effective voltage across the critical load side not only gradually stabilizes at 220V, but the current amplitude on the transmission line is significantly reduced, with an effective value of approximately 13.3A.

[0164] This demonstrates that, regardless of whether the effective value of the critical load voltage is greater than or less than its reference value, the control strategy proposed in this application is effective in controlling the magnitude of the transmission line current while maintaining the critical load voltage. Compared with existing technologies, this voltage stabilization control strategy for renewable energy grid-connected systems based on electric springs has the following beneficial effects: it achieves synergistic optimization of critical load voltage stabilization and system energy efficiency improvement, fully considers the active power compensation limit, enhances the robustness and engineering practicality of the system, explores the active-reactive hybrid compensation potential of the second-generation electric spring (ES-2), and exhibits superior overall performance.

[0165] The technique of generating pulse width modulation (PWM) signals to control switching devices employs a carrier comparison modulation method. The modulating signal is compared with a high-frequency triangular wave carrier signal. When the instantaneous value of the modulating signal is greater than that of the carrier signal, a high-level pulse is generated; otherwise, a low-level pulse is generated, producing a pulse sequence whose width is proportional to the amplitude of the modulating signal. This PWM signal directly drives the fully controllable switching device in the electric spring circuit, and the desired output voltage waveform is synthesized by controlling the on-time and off-time of the switching device.

[0166] The entire control strategy consists of three parts that form a complete closed-loop control process: the setpoint calculation layer solves for the optimal operating point through a geometric optimization algorithm; the reference value generation layer transforms the optimization objective into specific control commands; and the execution control layer achieves precise tracking of the physical system through high-frequency switching control.

[0167] This application also provides a voltage stabilization and line loss coordinated control device, including:

[0168] The analysis module calculates the minimum transmission line current amplitude based on the grid voltage and critical load voltage reference values ​​through geometric analysis. This geometric analysis includes: based on a comparison between the grid voltage amplitude and the critical load voltage reference value, distinguishing between two cases: when the grid voltage amplitude is less than the critical load voltage reference value, the minimum transmission line current amplitude is calculated as a first difference using a first geometric relationship, where the first difference is the difference between the radius parameter and the distance between the centers of the two circles represented by the first geometric relationship; when the grid voltage amplitude is greater than the critical load voltage reference value, the minimum transmission line current amplitude is calculated as a second difference using a second geometric relationship, where the second difference is the difference between the distance between the centers of the two circles represented by the second geometric relationship and the radius parameter.

[0169] The amplitude module calculates the real part and imaginary part of the transmission line current based on the minimum transmission line current amplitude.

[0170] The voltage module calculates the reference value of the power spring output voltage based on the real part of the transmission line current, the imaginary part of the transmission line current, and the grid voltage.

[0171] The reference module decomposes the output voltage reference value of the electric spring into an amplitude reference value and a phase reference value;

[0172] The signal module uses a proportional resonant controller to generate a modulation signal based on the amplitude reference value and the phase reference value;

[0173] The control module compares the modulation signal with the carrier signal to generate a pulse width modulation signal to control the switching device of the electric spring.

[0174] This application also provides an electronic device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the method described above.

[0175] This application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed in a computer, causes the computer to perform the above-described method.

[0176] The above description of the embodiments is provided to enable those skilled in the art to understand and apply this application. Those skilled in the art will readily make various modifications to the above embodiments and apply the general principles described herein to other embodiments without inventive effort. Therefore, this application is not limited to the above embodiments, and any improvements and modifications made to this application based on the disclosure thereof should be within the scope of protection of this application.

Claims

1. A method for coordinated control of voltage stabilization and line loss, characterized in that, The method comprises the following steps: According to the grid voltage and the key load voltage reference value, the minimum transmission line current amplitude is calculated by geometric analysis, which includes: according to the amplitude comparison result of the grid voltage and the key load voltage reference value, two cases are distinguished, when the amplitude of the grid voltage is less than the amplitude of the key load voltage reference value, the minimum transmission line current amplitude is calculated by the first geometric relation as the first difference, the first difference is the difference between the radius parameter and the distance between the two circle centers represented by the first geometric relation; when the amplitude of the grid voltage is greater than the amplitude of the key load voltage reference value, the minimum transmission line current amplitude is calculated by the second geometric relation as the second difference, the second difference is the difference between the distance between the two circle centers represented by the second geometric relation and the radius parameter; According to the minimum transmission line current amplitude, the corresponding transmission line current real part and transmission line current imaginary part are calculated; According to the transmission line current real part, the transmission line current imaginary part and the grid voltage, the power spring output voltage reference value is calculated; The power spring output voltage reference value is decomposed into amplitude reference value and phase reference value; Using a proportional resonant controller, a modulation signal is generated according to the amplitude reference value and the phase reference value; The modulation signal is compared with the carrier signal to generate a pulse width modulation signal to control the switching device of the power spring.

2. The method of claim 1, wherein, According to the grid voltage and the key load voltage reference value, the minimum transmission line current amplitude is calculated by geometric analysis, including: In the geometric analysis, the circular equation constraint of the transmission line current is established; The circular equation constraint represents that the square of the difference between the transmission line current real part and the first circle center parameter plus the square of the difference between the transmission line current imaginary part and the second circle center parameter is equal to the square of the radius parameter.

3. The method of claim 1, wherein, According to the grid voltage and the key load voltage reference value, the minimum transmission line current amplitude is calculated by geometric analysis, including: The first circle center parameter is calculated; The first circle center parameter is: (grid voltage amplitude / transmission line impedance modulus) × cos(grid voltage phase angle-transmission line impedance angle).

4. The method of claim 1, wherein, According to the grid voltage and the key load voltage reference value, the minimum transmission line current amplitude is calculated by geometric analysis, including: The second circle center parameter is calculated; The second circle center parameter is: (grid voltage amplitude / transmission line impedance modulus) × sin(grid voltage phase angle-transmission line impedance angle).

5. The method of claim 1, wherein, According to the grid voltage and the key load voltage reference value, the minimum transmission line current amplitude is calculated by geometric analysis, including: The radius parameter is calculated; The radius parameter is the ratio of the key load voltage reference value amplitude to the transmission line impedance modulus.

6. The method of claim 1, wherein, According to the grid voltage and the key load voltage reference value, the minimum transmission line current amplitude is calculated by geometric analysis, including: The distance between the two circle centers is calculated; The distance between the two circle centers is the square root of the sum of the squares of the first circle center parameter and the second circle center parameter.

7. The method of claim 1, wherein, According to the minimum transmission line current amplitude, the corresponding transmission line current real part and transmission line current imaginary part are calculated, including: The transmission line current real part is calculated; The transmission line current real part: (first center parameter x (two center distance-radius parameter)) / two center distance; Calculate the transmission line current imaginary part; The transmission line current imaginary part: (second center parameter x (radius parameter-two center distance)) / two center distance.

8. A voltage stabilization and line loss coordination control device, characterized in that, Comprise: The analysis module, according to the grid voltage and key load voltage reference value, through the geometric analysis calculation minimum transmission line current amplitude, the geometric analysis includes: according to the amplitude of the grid voltage and the amplitude of the key load voltage reference value Comparison result, distinguish two cases, when the amplitude of the grid voltage is less than the amplitude of the key load voltage reference value, through the first geometric relation calculation minimum transmission line current amplitude is the first difference value, the first difference value is the difference between the radius parameter and the two center distance represented by the first geometric relation; When the amplitude of the grid voltage is greater than the amplitude of the key load voltage reference value, through the second geometric relation calculation minimum transmission line current amplitude is the second difference value, the second difference value is the difference between the two center distance represented by the second geometric relation and the radius parameter; Amplitude module, according to the minimum transmission line current amplitude, calculate the corresponding transmission line current real part and transmission line current imaginary part; Voltage module, according to the transmission line current real part, the transmission line current imaginary part and the grid voltage, calculate the power spring output voltage reference value; Reference module, the power spring output voltage reference value is decomposed into amplitude reference value and phase reference value; Signal module, using proportional resonant controller, according to the amplitude reference value and the phase reference value, generate modulation signal; Control module, the modulation signal and carrier signal comparison, generate pulse width modulation signal to control the switching device of the power spring.

9. An electronic device, comprising: Including memory and processor, the memory has computer program stored, the processor executes the computer program, realize the method as claimed in any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, Its storage has computer program, when the computer program executes in the computer, make computer execute the method as claimed in any one of claims 1-7.

Images