Smooth power output control method and device for wind storage fusion system

Abstract

The invention discloses a power smooth output control method and device for a wind storage fusion system, the wind storage fusion system is adopted and comprises an electrochemical energy storage system and a super-capacitor energy storage system, and the method comprises the steps that smooth output reference power and actual output power within a preset time period before the current control time period of a wind turbine generator are determined; determining the power deviation between the smooth output reference power and the actual output power of the wind turbine generator; decomposing the power deviation through a first-order low-pass filter to obtain corresponding low-frequency power and high-frequency power; determining the smooth output reference power of the wind turbine generator in the next control time period according to the low-frequency power, and performing charge and discharge control on the electrochemical energy storage system in the current control time period; and performing charging and discharging control on the super-capacitor energy storage system in the current control time period according to the high-frequency power. Therefore, the harmonic content is reduced, the stability of wind power output is improved, large-scale grid connection and consumption of wind power are promoted, and stable operation of a power grid is ensured.

Description

Technical Field

[0001] The present invention relates to the field of power control technology, and in particular to a power smoothing output control method and device for a wind-storage fusion system. Background Art

[0002] With the increasing demand for clean energy, wind power resources, as a green and renewable energy, have gradually become an important part of the energy structure. Unlike other energy sources (such as thermal power or hydropower), wind energy has the characteristics of randomness, volatility and intermittency. Based on this, the output of wind power is unstable. With the large-scale grid connection of wind power, it will bring challenges to the dispatching and stable operation of the power grid.

[0003] In the prior art, the volatility of wind farm output power can be reduced by the following methods:

[0004] Method 1: Rationally plan the location and spacing of wind turbines in the wind farm to reduce the impact of the wake effect and make the overall output power of the wind farm more stable;

[0005] Method 2: Using advanced wind turbine control strategies (such as variable speed-variable pitch control), the wind turbine's operating state can be automatically adjusted according to the real-time changes in wind speed, making the wind turbine output power more stable;

[0006] Method three: Combine wind power with other energy sources (such as solar energy or hydropower) to form a complementary power generation system, so that the power output of the entire system is more stable.

[0007] However, in the above-mentioned prior art, there is still a certain degree of volatility in wind power output, thereby failing to ensure the stable operation of the power grid. Summary of the invention

[0008] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0009] To this end, the present invention proposes a power smoothing output control method for a wind-storage fusion system, which decomposes the power deviation between the wind turbine smoothing output reference power and the actual output power to obtain the corresponding low-frequency power and high-frequency power, and controls the charging and discharging of the electrochemical energy storage system and the supercapacitor energy storage system in the current control time period according to the low-frequency power and the high-frequency power, thereby reducing the harmonic content and improving the stability of wind power output, so that wind power can better participate in the dispatching arrangement of the power grid, promote large-scale grid connection and consumption of wind power, and ensure the stable operation of the power grid.

[0010] Another object of the present invention is to provide a power smoothing output control device for a wind-storage fusion system.

[0011] To achieve the above object, the present invention proposes a power smoothing output control method for a wind-storage fusion system, wherein the wind-storage fusion system includes an electrochemical energy storage system and a supercapacitor energy storage system, and the method includes:

[0012] Determine the smoothed output reference power and actual output power of the wind turbine generator set within a preset time period before the current control time period;

[0013] Determining a power deviation between a smoothed output reference power and an actual output power of the wind turbine generator set;

[0014] Decomposing the power deviation by a first-order low-pass filter to obtain corresponding low-frequency power and high-frequency power;

[0015] Determine the smoothed output reference power of the wind turbine set in the next control time period according to the low-frequency power, and perform charge and discharge control on the electrochemical energy storage system in the current control time period;

[0016] The supercapacitor energy storage system is controlled to charge and discharge during the current control time period according to the high-frequency power.

[0017] The power smoothing output control method for a wind-storage fusion system according to an embodiment of the present invention may also have the following additional technical features:

[0018] In one embodiment of the present invention, determining the smoothed output reference power of the wind turbine in the next control time period according to the low-frequency power, and controlling the charge and discharge of the electrochemical energy storage system in the current control time period, includes:

[0019] Acquire a first state of charge SOC of the electrochemical energy storage system, and determine a first charging coefficient and a first discharging coefficient corresponding to the electrochemical energy storage system based on the first SOC;

[0020] Determining, by calculation, a first maximum discharge power and a first maximum charge power corresponding to the electrochemical energy storage system in a current control time period according to a first charge coefficient and a first discharge coefficient corresponding to the electrochemical energy storage system;

[0021] Determining a first target state of the electrochemical energy storage system based on the low-frequency power, the first maximum charging power, and the first maximum discharging power;

[0022] Determine, according to the first target state, a smoothed output reference power of the wind turbine generator set in the next control time period and a first charge and discharge target power corresponding to the electrochemical energy storage system in the current control time period;

[0023] The electrochemical energy storage system is controlled to charge and discharge according to the first charge and discharge target power.

[0024] In one embodiment of the present invention, determining the first target state of the electrochemical energy storage system based on the low-frequency power, the first maximum charging power, and the first maximum discharging power includes:

[0025] If the low-frequency power is greater than or equal to the first maximum charging power and less than or equal to the first maximum discharging power, determining that the first target state of the electrochemical energy storage system is the first state;

[0026] If the low-frequency power is greater than the first maximum discharge power, determining that the first target state of the electrochemical energy storage system is the second state;

[0027] If the low-frequency power is less than the first maximum charging power, it is determined that the first target state of the electrochemical energy storage system is the third state.

[0028] In one embodiment of the present invention, determining the smoothed output reference power of the wind turbine in the next control time period and the first charge and discharge target power corresponding to the electrochemical energy storage system in the current control time period according to the first target state includes:

[0029] If the first target state is the first state, the smoothed output reference power of the wind turbine set in the next control time period remains unchanged, and the first charge and discharge target power of the electrochemical energy storage system is the low-frequency power;

[0030] If the first target state is the second state, the down-conversion coefficient of the wind turbine set in the next control time period is determined according to the first SOC, and the smoothed output reference power is determined according to the down-conversion coefficient; the first charge and discharge target power of the electrochemical energy storage system is the first maximum discharge power;

[0031] If the first target state is the third state, the rising transformation coefficient of the wind turbine set in the next control time period is determined according to the first SOC, and the smooth output reference power is determined according to the rising transformation coefficient; the first charging and discharging target power of the electrochemical energy storage system is the first maximum charging power.

[0032] In one embodiment of the present invention, the charging and discharging control of the electrochemical energy storage system according to the first charging and discharging target power includes: adopting a grid-based control strategy to track the first charging and discharging target power to control the charging and discharging of the electrochemical energy storage system.

[0033] In one embodiment of the present invention, the charging and discharging control of the supercapacitor energy storage system in the current control time period according to the high-frequency power includes:

[0034] Acquire a second SOC of the supercapacitor energy storage system, and determine a second charging coefficient and a second discharging coefficient corresponding to the supercapacitor energy storage system based on the second SOC;

[0035] Determine, by calculation, a second maximum discharge power and a second maximum charge power corresponding to the supercapacitor energy storage system in the current control time period according to the second charge coefficient and the second discharge coefficient corresponding to the supercapacitor energy storage system;

[0036] Determining a second target state of the supercapacitor energy storage system based on the high-frequency power, the second maximum charging power, and the second maximum discharging power;

[0037] Determine, according to the second target state, a second charging and discharging target power corresponding to the supercapacitor energy storage system in the current control time period;

[0038] The supercapacitor energy storage system is controlled to charge and discharge according to the second charge and discharge target power.

[0039] In one embodiment of the present invention, determining the second target state of the supercapacitor energy storage system based on the high-frequency power, the second maximum charging power, and the second maximum discharging power includes:

[0040] If the high-frequency power is greater than or equal to the second maximum charging power and less than or equal to the second maximum discharging power, determining that the second target state of the supercapacitor energy storage system is the fourth state;

[0041] If the high-frequency power is greater than the second maximum discharge power, determining that the second target state of the supercapacitor energy storage system is the fifth state;

[0042] If the high-frequency power is less than the second maximum charging power, it is determined that the second target state of the supercapacitor energy storage system is the sixth state.

[0043] In one embodiment of the present invention, determining the second charging and discharging target power corresponding to the supercapacitor energy storage system in the current control time period according to the second target state includes:

[0044] If the second target state is the fourth state, the second charging and discharging target power corresponding to the supercapacitor energy storage system in the current control time period is the high-frequency power;

[0045] If the second target state is the fifth state, the second charge and discharge target power corresponding to the supercapacitor energy storage system in the current control time period is the second maximum discharge power;

[0046] If the second target state is the sixth state, the second charging and discharging target power corresponding to the supercapacitor energy storage system in the current control time period is the second maximum charging power.

[0047] In one embodiment of the present invention, the charging and discharging control of the supercapacitor energy storage system according to the second charging and discharging target power includes: adopting a grid-based control strategy to track the second charging and discharging target power to control the charging and discharging of the supercapacitor energy storage system.

[0048] To achieve the above object, the present invention proposes a power smoothing output control device for a wind-storage fusion system, wherein the wind-storage fusion system includes an electrochemical energy storage system and a supercapacitor energy storage system, and the device includes:

[0049] The first determination module is used to determine the smoothed output reference power and the actual output power of the wind turbine generator set within a preset time period before the current control time period;

[0050] A second determination module is used to determine a power deviation between the smoothed output reference power and the actual output power of the wind turbine generator set based on the smoothed output reference power and the actual output power;

[0051] A processing module, used for decomposing the power deviation through a first-order low-pass filter to obtain corresponding low-frequency power and high-frequency power;

[0052] A first control module, used to determine the smoothed output reference power of the wind turbine set in the next control time period according to the low-frequency power, and to perform charge and discharge control on the electrochemical energy storage system in the current control time period;

[0053] The second control module is used to control the charging and discharging of the supercapacitor energy storage system in the current control time period according to the high-frequency power.

[0054] Another object of the present invention is to provide an electronic device, comprising:

[0055] at least one processor; and

[0056] a memory communicatively connected to the at least one processor; wherein,

[0057] The memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform any one of the methods described in the above aspect.

[0058] Another object of the present invention is to provide a computer storage medium, wherein the computer storage medium stores computer executable instructions; after the computer executable instructions are executed by a processor, the computer executes any one of the methods described in the above aspect.

[0059] The power smoothing output control method and device for a wind-storage fusion system of an embodiment of the present invention decomposes the power deviation between the wind turbine smoothing output reference power and the actual output power to obtain the corresponding low-frequency power and high-frequency power, and controls the charging and discharging of the electrochemical energy storage system and the supercapacitor energy storage system in the current control time period according to the low-frequency power and the high-frequency power, thereby reducing the harmonic content and improving the stability of wind power output, enabling wind power to better participate in the scheduling of the power grid, promoting large-scale grid connection and consumption of wind power, and ensuring the stable operation of the power grid.

[0060] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0062] Figure 1 is a flow chart of a power smoothing output control method for a wind-storage fusion system according to an embodiment of the present invention;

[0063] Figure 2 is a structural schematic diagram of a wind-storage fusion system according to an embodiment of the present invention;

[0064] Figure 3 is a schematic diagram of a control module according to an embodiment of the present invention;

[0065] Figure 4 is a calculation flow chart of a phase loop phase angle calculation module according to an embodiment of the present invention;

[0066] Figure 5 It is a structural diagram of a power smoothing output control device for a wind-storage fusion system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0067] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0068] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0069] The following describes a power smoothing output control method and device for a wind-storage fusion system proposed according to an embodiment of the present invention with reference to the accompanying drawings.

[0070] Figure 1 It is a flow chart of a power smoothing output control method for a wind-storage fusion system according to an embodiment of the present invention.

[0071] like Figure 1 As shown, the method includes:

[0072] S1, determining the smoothed output reference power and actual output power of the wind turbine generator set in a preset time period before the current control time period;

[0073] In one embodiment of the present invention, a wind farm may include n wind turbines, and each wind turbine has a corresponding wind-storage fusion system. In one embodiment of the present invention, the wind-storage fusion system may include a wind turbine, and a hybrid energy storage device is incorporated into the low-voltage AC side of the wind turbine transformer, wherein the hybrid energy storage device may include an electrochemical energy storage system and a supercapacitor energy storage system. Figure 2 Schematic diagram of a wind-storage fusion system proposed in an embodiment of the present invention. Figure 2 As shown, the wind-storage fusion system may include a power generation system (including an impeller, a rotating chain and a generator)-1, a converter-2, a box-type transformer-3, an electrochemical energy storage system-4, and a supercapacitor energy storage system-5. Among them, the converter-2 can convert the electric energy generated by the wind turbine into electric energy with the same voltage, frequency and phase as the power grid through AC-DC-AC conversion, and mainly includes a machine-side converter 2-1, a DC bus and capacitor 2-2, a grid-side converter 2-3, and a grid-connected circuit breaker 2-4; the high-voltage side 35kV of the box-type transformer-3 is connected to the wind farm collection line, and the low-voltage side 690V is connected to the 2-converter; the electrochemical energy storage system-4 can include a battery system 4-1, an inverter 4-2 and a circuit breaker 4-3, and the outlet of the circuit breaker 4-3 is connected to the corresponding wind turbine PCC (Point of Common Coupling); the supercapacitor energy storage system-5 can include a supercapacitor 5-1, an inverter 5-2 and a circuit breaker 5-3, wherein the outlet of the circuit breaker 5-3 is connected to the corresponding wind turbine PCC.

[0074] In one embodiment of the present invention, in response to the wind turbine generator set executing the wind power smooth output control mode, a smooth output reference power within a preset time period before a current control time period of the wind turbine generator set is determined.

[0075] Specifically, in one embodiment of the present invention, the average output power of the wind turbine generator set in a preset time period before the current control time period can be determined by a first formula, and the average output power is used as the smoothed output reference power, wherein the first formula is:

[0076]

[0077] Where j is the preset time period, is the power smoothing output reference value of the i-th wind turbine in the j-th time period, P W,i (jm) is the average output power of the i-th wind turbine in the jm time period.

[0078] Furthermore, in one embodiment of the present invention, the actual output power of each time period in a preset time period before the current control time period of the wind turbine generator set may be added together to obtain the actual output power of the wind turbine generator set in the preset time period before the current control time period.

[0079] Furthermore, in one embodiment of the present invention, the preset time period can be set as needed. For example, the preset time period can be 10 minutes, and each control time period is 1 minute.

[0080] S2, determining the power deviation between the wind turbine smoothed output reference power and the actual output power;

[0081] In one embodiment of the present invention, after determining the wind turbine smoothed output reference power and the actual output power through the above steps, the power deviation between the wind turbine smoothed output reference power and the actual output power can be determined.

[0082] Specifically, in one embodiment of the present invention, the power deviation between the wind turbine smoothed output reference power and the actual output power may be determined by a second formula, wherein the second formula is:

[0083]

[0084] in, is the smoothed output reference power of the i-th wind turbine in the j-time period, is the actual power generated by the i-th wind turbine in the j-time period.

[0085] S3, decomposing the power deviation through a first-order low-pass filter to obtain the corresponding low-frequency power and high-frequency power;

[0086] In one embodiment of the present invention, the power deviation is obtained through the above steps, and the power deviation can be decomposed by a first-order low-pass filter to obtain corresponding low-frequency power and high-frequency power.

[0087] Specifically, in one embodiment of the present invention, a first-order low-pass filter may be used to decompose the power deviation through a third formula to obtain the corresponding low-frequency power, wherein the third formula is:

[0088]

[0089] Among them, s is the Laplace operator and τ is the time parameter.

[0090] And, in one embodiment of the present invention, the power deviation can be decomposed by a first-order low-pass filter through a fourth formula to obtain the corresponding high-frequency power, wherein the fourth formula is:

[0091]

[0092] S4, determining the smoothed output reference power of the wind turbine generator set in the next control time period according to the low-frequency power, and controlling the charge and discharge of the electrochemical energy storage system in the current control time period;

[0093] In one embodiment of the present invention, after obtaining the low-frequency power through the above steps, the smoothed output reference power of the wind turbine in the next control time period can be determined according to the low-frequency power, and the charge and discharge control of the electrochemical energy storage system in the current control time period can be performed.

[0094] Specifically, in one embodiment of the present invention, the method for determining the smoothed output reference power of the wind turbine generator set in the next control time period according to the low-frequency power and controlling the charge and discharge of the electrochemical energy storage system in the current control time period may include the following steps:

[0095] S41, obtaining a first state of charge SOC of the electrochemical energy storage system, and determining a first charging coefficient and a first discharging coefficient corresponding to the electrochemical energy storage system based on the first SOC;

[0096] In one embodiment of the present invention, after obtaining the first SOC of the electrochemical energy storage system, the first charging coefficient and the first discharging coefficient corresponding to the electrochemical energy storage system can be determined based on the first SOC by the fifth formula, wherein the fifth formula is:

[0097]

[0098] Among them, SOC B,i is the first SOC of the electrochemical energy storage system. When the discharge coefficient is used for timing, K B_d,iis the first discharge coefficient of the electrochemical energy storage system; when When the charging coefficient is negative, K B_c,i It is the first charging coefficient of the electrochemical energy storage system.

[0099] S42, determining by calculation a first maximum discharge power and a first maximum charge power corresponding to the electrochemical energy storage system in the current control time period according to a first charge coefficient and a first discharge coefficient corresponding to the electrochemical energy storage system;

[0100] Among them, in one embodiment of the present invention, after obtaining the first charging coefficient and the first discharging coefficient through the above steps, the first maximum discharge power and the first maximum charging power corresponding to the electrochemical energy storage system in the current control time period can be determined by calculation according to the first charging coefficient and the first discharging coefficient corresponding to the electrochemical energy storage system.

[0101] Specifically, in one embodiment of the present invention, the first maximum discharge power and the first maximum charge power corresponding to the electrochemical energy storage system in the current control time period can be calculated and determined by a sixth formula according to the first charge coefficient and the first discharge coefficient corresponding to the electrochemical energy storage system, wherein the sixth formula is:

[0102]

[0103] in, is the first maximum discharge power of the electrochemical energy storage system corresponding to the i-th wind turbine in the j-th time period, is the first maximum charging power of the electrochemical energy storage system corresponding to the i-th wind turbine in the j-th time period, P B,max It is the rated charge and discharge power of electrochemical energy storage.

[0104] S43, determining a first target state of the electrochemical energy storage system based on the low-frequency power, the first maximum charging power, and the first maximum discharging power;

[0105] In one embodiment of the present invention, after obtaining the low-frequency power, the first maximum charging power and the first maximum discharging power through the above steps, the first target state of the electrochemical energy storage system can be determined based on the low-frequency power, the first maximum charging power and the first maximum discharging power.

[0106] Specifically, in one embodiment of the present invention, the method for determining the first target state of the electrochemical energy storage system based on the low-frequency power, the first maximum charging power and the first maximum discharging power may include the following steps:

[0107] S431, if the low-frequency power is greater than or equal to the first maximum charging power and less than or equal to the first maximum discharging power, determining that the first target state of the electrochemical energy storage system is the first state;

[0108] In one embodiment of the present invention, if Then it is determined that the first target state of the electrochemical energy storage system is the first state.

[0109] S432, if the low-frequency power is greater than the first maximum discharge power, determining that the first target state of the electrochemical energy storage system is the second state;

[0110] In one embodiment of the present invention, if It is then determined that the first target state of the electrochemical energy storage system is the second state.

[0111] S433: If the low-frequency power is less than the first maximum charging power, determine that the first target state of the electrochemical energy storage system is the third state.

[0112] In one embodiment of the present invention, if It is then determined that the first target state of the electrochemical energy storage system is the third state.

[0113] S44, determining the smoothed output reference power of the wind turbine generator set in the next control time period and the first charging and discharging target power corresponding to the electrochemical energy storage system in the current control time period according to the first target state;

[0114] In one embodiment of the present invention, after determining the first target state of the electrochemical energy storage system through the above steps, the smoothed output reference power of the wind turbine in the next control time period and the first charging and discharging target power corresponding to the electrochemical energy storage system in the current control time period can be determined according to the first target state.

[0115] Specifically, in one embodiment of the present invention, the method for determining the smoothed output reference power of the wind turbine in the next control time period and the first charging and discharging target power corresponding to the electrochemical energy storage system in the current control time period according to the first target state may include the following steps:

[0116] S441, if the first target state is the first state, the smoothed output reference power of the wind turbine generator set in the next control time period remains unchanged, and the first charging and discharging target power of the electrochemical energy storage system is the low-frequency power;

[0117] In one embodiment of the present invention, if the first target state is the first state, the smoothed output reference power of the wind turbine generator set in the next control time period is The first charge and discharge target power of the electrochemical energy storage system is

[0118] S442, if the first target state is the second state, determining a down-conversion coefficient of the wind turbine generator set in the next control time period according to the first SOC, and determining a smoothed output reference power according to the down-conversion coefficient;

[0119] In one embodiment of the present invention, if the first target state is the second state, the down-conversion coefficient of the wind turbine generator set in the next control time period is determined according to the first SOC by the seventh formula, wherein the seventh formula is:

[0120]

[0121] Among them, k 0 It is the basic coefficient of the smooth output reference power conversion.

[0122] And, in one embodiment of the present invention, after the down-conversion coefficient is obtained through the above steps, the smoothed output reference power can be determined according to the down-conversion coefficient through the eighth formula, where the eighth formula is:

[0123]

[0124] Among them, ΔT is the control time step.

[0125] S443, the first charge and discharge target power of the electrochemical energy storage system is the first maximum discharge power;

[0126] In one embodiment of the present invention, if the first target state is the second state, the first charge and discharge target power of the electrochemical energy storage system is in, is the first maximum discharge power.

[0127] S444, if the first target state is the third state, determining a rising transformation coefficient of the wind turbine generator set in the next control time period according to the first SOC, and determining a smoothed output reference power according to the rising transformation coefficient;

[0128] In one embodiment of the present invention, if the first target state is the third state, the rising conversion coefficient of the wind turbine generator set in the next control time period is determined according to the first SOC by the ninth formula, wherein the ninth formula is:

[0129]

[0130] And, in one embodiment of the present invention, after the up-conversion coefficient is obtained through the above steps, the smoothed output reference power can be determined according to the up-conversion coefficient through the tenth formula, where the tenth formula is:

[0131]

[0132] S445, the first charging and discharging target power of the electrochemical energy storage system is the first maximum charging power.

[0133] In one embodiment of the present invention, if the first target state is the third state, the first charge and discharge target power of the electrochemical energy storage system is in, is the first maximum charging power.

[0134] S45, controlling the charge and discharge of the electrochemical energy storage system according to the first charge and discharge target power.

[0135] In one embodiment of the present invention, after the first charge and discharge target power is obtained through the above steps, the charge and discharge control of the electrochemical energy storage system can be performed according to the first charge and discharge target power.

[0136] Specifically, in one embodiment of the present invention, the method for controlling the charge and discharge of the electrochemical energy storage system according to the first charge and discharge target power may include: adopting a grid-based control strategy to track the first charge and discharge target power to control the charge and discharge of the electrochemical energy storage system.

[0137] Among them, in one embodiment of the present invention, Figure 3 Schematic diagram of a control module according to an embodiment of the present invention. Figure 3 As shown, the control module includes a phase-locked loop phase angle calculation module 10, a current outer loop calculation module 11 and a current inner loop calculation module 12, wherein the current outer loop calculation module 11 includes power calculation 11-1 and PI calculation 11-2, and the current inner loop calculation module 12 includes PI calculation 12-1 and 12-2, dq coordinate transformation 12-3 and dq coordinate inverse transformation 12-4.

[0138] Furthermore, in one embodiment of the present invention, the input of the phase-locked loop phase angle calculation module 10 is the three-phase voltage measured by the power grid, and the output is the power grid frequency and phase angle. Figure 4 This is the calculation flow chart of the phase angle calculation module of the phase loop.

[0139] like Figure 4 As shown, the initial phase is set to θ, which is substituted into the dq coordinate transformation, and the grid voltage uod and uoq values ​​are calculated by the eleventh formula, where the eleventh formula is:

[0140]

[0141] And, in one embodiment of the present invention, u oq Substitute the PI formula into the grid frequency and calculate it. The PI formula is:

[0142]

[0143] Among them, Kp_PLL is the proportionality coefficient, K i_PLL is the integration coefficient.

[0144] Further, in one embodiment of the present invention, ω is integrated and the grid phase angle is calculated by the twelfth formula, wherein the twelfth formula is:

[0145]

[0146] Among them, in one embodiment of the present invention, if u oq If it is not within the preset range, the calculated phase angle is substituted into the eleventh formula, the PI formula and the twelfth formula to recalculate the grid frequency and phase angle until u oq In the preset range, the corresponding grid frequency and phase angle are determined. In one embodiment of the present invention, the preset range can be set as required, for example, the preset range is (0, 0.01).

[0147] Furthermore, in one embodiment of the present invention, the input of the current outer loop calculation module 11 is the three-phase voltage u measured by the power grid. oabc , energy storage output three-phase current i abc 、The first charge and discharge target power Reactive power reference value The output is the energy storage PCC point dq axis current control target value i dq *. Among them, reactive power reference value It can be set as needed, for example,

[0148] Among them, the three-phase voltage u measured by the power grid is converted into oabc , three-phase current i abc Convert to u odq and i dq , and substitute it into the thirteenth formula to calculate the grid measured active power P B,i and reactive Q B,i , where the thirteenth formula is:

[0149]

[0150] And, in one embodiment of the present invention, P B,i , Q B,i , and Substitute into the PI formula to calculate the dq axis current control target value i at the energy storage PCC point dq *, where the PI formula is:

[0151]

[0152] Among them, K p_PQis the proportionality coefficient, K i_PQ is the integration coefficient.

[0153] Furthermore, in one embodiment of the present invention, the current inner loop calculation module converts the three-phase current measurement value i output by the inverter in the electrochemical energy storage system into abc Converted into dq axis current i through dq transformation dq , and calculate the voltage value corresponding to the current loop by the fourteenth formula, where the fourteenth formula is as follows:

[0154]

[0155] Among them, K p_c is the proportionality coefficient, K i_c is the integration coefficient.

[0156] And, in one embodiment of the present invention, the dq axis cross influence term is introduced through the fifteenth formula to obtain the inverter dq axis voltage control target value, wherein the fifteenth formula is:

[0157]

[0158] Furthermore, in one embodiment of the present invention, the inverter dq axis voltage control target value u dq *Substitute into the dq coordinate inverse transformation and calculate the inverter modulation voltage control target value u through the sixteenth formula abc *, the sixteenth formula is:

[0159]

[0160] And, in one embodiment of the present invention, the inverter modulation voltage control target value u is obtained through the above steps abc *Finally, the target value u can be controlled by inverter modulation voltage abc *Control the electrochemical energy storage system.

[0161] S5, controlling the charging and discharging of the supercapacitor energy storage system in the current control time period according to the high-frequency power.

[0162] In one embodiment of the present invention, after the high-frequency power is obtained through the above steps, the charging and discharging of the supercapacitor energy storage system in the current control time period can be controlled according to the high-frequency power.

[0163] Specifically, in one embodiment of the present invention, the method for controlling the charging and discharging of the supercapacitor energy storage system in the current control time period according to the high-frequency power may include the following steps:

[0164] S51, obtaining a second SOC of the supercapacitor energy storage system, and determining a second charging coefficient and a second discharging coefficient corresponding to the supercapacitor energy storage system based on the second SOC;

[0165] In one embodiment of the present invention, after obtaining the second SOC of the supercapacitor energy storage system, the second charging coefficient and the second discharging coefficient corresponding to the supercapacitor energy storage system can be determined based on the second SOC by the seventeenth formula, wherein the seventeenth formula is:

[0166]

[0167] Among them, SOC S,i is the second SOC of the supercapacitor energy storage system. When the discharge coefficient is used for timing, K S_d,i is the second discharge coefficient of the supercapacitor energy storage system; when When the charging coefficient is negative, K S_c,i is the second charging coefficient of the supercapacitor energy storage system.

[0168] S52, determining by calculation a second maximum discharge power and a second maximum charge power corresponding to the supercapacitor energy storage system in the current control time period according to a second charge coefficient and a second discharge coefficient corresponding to the supercapacitor energy storage system;

[0169] Among them, in one embodiment of the present invention, after obtaining the second charging coefficient and the second discharging coefficient through the above steps, the second maximum discharge power and the second maximum charging power corresponding to the supercapacitor energy storage system in the current control time period can be determined by calculation according to the second charging coefficient and the second discharge coefficient corresponding to the supercapacitor energy storage system.

[0170] Specifically, in one embodiment of the present invention, the second maximum discharge power and the second maximum charging power corresponding to the supercapacitor energy storage system in the current control time period can be calculated and determined by the eighteenth formula according to the second charging coefficient and the second discharge coefficient corresponding to the supercapacitor energy storage system, wherein the eighteenth formula is:

[0171]

[0172] in, is the second maximum discharge power of the supercapacitor energy storage system corresponding to the i-th wind turbine in the j-th time period, is the second maximum charging power of the supercapacitor energy storage system corresponding to the i-th wind turbine in the j-th time period, P S,max It is the rated charge and discharge power of supercapacitor energy storage.

[0173] S53, determining a second target state of the supercapacitor energy storage system based on the high frequency power, the second maximum charging power, and the second maximum discharging power;

[0174] In one embodiment of the present invention, after obtaining the second maximum charging power and the second maximum discharging power through the above steps, the second target state of the supercapacitor energy storage system can be determined based on the high-frequency power, the second maximum charging power and the second maximum discharging power.

[0175] In one embodiment of the present invention, the method for determining the second target state of the supercapacitor energy storage system based on the high-frequency power, the second maximum charging power and the second maximum discharging power may include the following steps:

[0176] S531, if the high-frequency power is greater than or equal to the second maximum charging power and less than or equal to the second maximum discharging power, determining that the second target state of the supercapacitor energy storage system is the fourth state;

[0177] In one embodiment of the present invention, if It is determined that the second target state of the supercapacitor energy storage system is the fourth state.

[0178] S532, if the high frequency power is greater than the second maximum discharge power, determining that the second target state of the supercapacitor energy storage system is the fifth state;

[0179] In one embodiment of the present invention, if It is determined that the first target state of the supercapacitor energy storage system is the fifth state.

[0180] S533: If the high-frequency power is less than the second maximum charging power, determine that the second target state of the supercapacitor energy storage system is the sixth state.

[0181] In one embodiment of the present invention, if It is determined that the second target state of the supercapacitor energy storage system is the sixth state.

[0182] S54, determining a second charging and discharging target power corresponding to the supercapacitor energy storage system in the current control time period according to the second target state;

[0183] In one embodiment of the present invention, after the second target state of the supercapacitor energy storage system is determined through the above steps, the second charging and discharging target power corresponding to the supercapacitor energy storage system in the current control time period can be determined according to the second target state.

[0184] Specifically, in one embodiment of the present invention, the method for determining the second charging and discharging target power corresponding to the supercapacitor energy storage system in the current control time period according to the second target state may include the following steps:

[0185] S541, if the second target state is the fourth state, the second charging and discharging target power corresponding to the supercapacitor energy storage system in the current control time period is high-frequency power;

[0186] In one embodiment of the present invention, if the second target state is the fourth state, the second charge and discharge target power corresponding to the supercapacitor energy storage system in the current control time period is

[0187] S542, if the second target state is the fifth state, the second charge and discharge target power corresponding to the supercapacitor energy storage system in the current control time period is the second maximum discharge power;

[0188] In one embodiment of the present invention, if the second target state is the fifth state, the second charge and discharge target power corresponding to the supercapacitor energy storage system in the current control time period is

[0189] S543: If the second target state is the sixth state, the second charging and discharging target power corresponding to the supercapacitor energy storage system in the current control time period is the second maximum charging power.

[0190] In one embodiment of the present invention, if the second target state is the sixth state, the second charge and discharge target power corresponding to the supercapacitor energy storage system in the current control time period is

[0191] S55, controlling the charging and discharging of the supercapacitor energy storage system according to the second charging and discharging target power.

[0192] In one embodiment of the present invention, after the second charging and discharging target power is obtained through the above steps, the charging and discharging of the supercapacitor energy storage system can be controlled according to the second charging and discharging target power.

[0193] Specifically, in one embodiment of the present invention, the method for controlling the charging and discharging of the supercapacitor energy storage system according to the second charging and discharging target power can refer to the method for controlling the charging and discharging of the electrochemical energy storage system according to the first charging and discharging target power, and the embodiment of the present disclosure will not be repeated here.

[0194] Furthermore, in one embodiment of the present invention, when the first SOC or the second SOC is too low or too high, the electrochemical energy storage system or the supercapacitor energy storage system can be automatically charged or discharged by adjusting the smooth power output reference value, so that the energy storage SOC of the wind storage fusion system is maintained at the optimal charge state. At the same time, the hybrid energy storage in the wind storage fusion system can further improve the service life of the energy storage system.

[0195] According to the power smoothing output control method for a wind-storage fusion system in an embodiment of the present invention, the power deviation between the wind turbine smoothing output reference power and the actual output power is decomposed to obtain the corresponding low-frequency power and high-frequency power, and the charging and discharging of the electrochemical energy storage system and the supercapacitor energy storage system in the current control time period are controlled according to the low-frequency power and the high-frequency power, thereby reducing the harmonic content and improving the stability of wind power output, so that wind power can better participate in the dispatching arrangement of the power grid, promote large-scale grid connection and consumption of wind power, and ensure the stable operation of the power grid.

[0196] In order to implement the above embodiment, Figure 5 As shown, in this embodiment, a power smoothing output control device 10 for a wind-storage fusion system is also provided. The wind-storage fusion system includes an electrochemical energy storage system and a supercapacitor energy storage system. The device includes:

[0197] The first determination module 501 is used to determine the smoothed output reference power and the actual output power of the wind turbine generator set within a preset time period before the current control time period;

[0198] A second determination module 502 is used to determine a power deviation between the smoothed output reference power and the actual output power of the wind turbine generator set based on the smoothed output reference power and the actual output power;

[0199] A processing module 503 is used to decompose the power deviation through a first-order low-pass filter to obtain corresponding low-frequency power and high-frequency power;

[0200] The first control module 504 is used to determine the smoothed output reference power of the wind turbine in the next control time period according to the low-frequency power, and to control the charge and discharge of the electrochemical energy storage system in the current control time period;

[0201] The second control module 505 is used to control the charging and discharging of the supercapacitor energy storage system in the current control time period according to the high-frequency power.

[0202] In one embodiment of the present invention, the first control module 504 is specifically configured to:

[0203] Acquire a first state of charge SOC of the electrochemical energy storage system, and determine a first charging coefficient and a first discharging coefficient corresponding to the electrochemical energy storage system based on the first SOC;

[0204] Determine, by calculation, a first maximum discharge power and a first maximum charge power corresponding to the electrochemical energy storage system in the current control time period according to a first charge coefficient and a first discharge coefficient corresponding to the electrochemical energy storage system;

[0205] Determining a first target state of the electrochemical energy storage system based on the low-frequency power, the first maximum charging power, and the first maximum discharging power;

[0206] Determine, according to the first target state, a smoothed output reference power of the wind turbine generator set in the next control time period and a first charge and discharge target power corresponding to the electrochemical energy storage system in the current control time period;

[0207] The charge and discharge of the electrochemical energy storage system is controlled according to the first charge and discharge target power.

[0208] Furthermore, in one embodiment of the present invention, the first control module 504 is further configured to:

[0209] If the low-frequency power is greater than or equal to the first maximum charging power and less than or equal to the first maximum discharging power, determining that the first target state of the electrochemical energy storage system is the first state;

[0210] If the low-frequency power is greater than the first maximum discharge power, determining that the first target state of the electrochemical energy storage system is the second state;

[0211] If the low-frequency power is less than the first maximum charging power, it is determined that the first target state of the electrochemical energy storage system is the third state.

[0212] Furthermore, in one embodiment of the present invention, the first control module 504 is further configured to:

[0213] If the first target state is the first state, the smoothed output reference power of the wind turbine generator set in the next control time period remains unchanged, and the first charging and discharging target power of the electrochemical energy storage system is the low-frequency power;

[0214] If the first target state is the second state, the down-conversion coefficient of the wind turbine generator set in the next control time period is determined according to the first SOC, and the smooth output reference power is determined according to the down-conversion coefficient; the first charge and discharge target power of the electrochemical energy storage system is the first maximum discharge power;

[0215] If the first target state is the third state, the rising conversion coefficient of the wind turbine group in the next control time period is determined according to the first SOC, and the smooth output reference power is determined according to the rising conversion coefficient; the first charging and discharging target power of the electrochemical energy storage system is the first maximum charging power.

[0216] Furthermore, in one embodiment of the present invention, the first control module 504 is further configured to:

[0217] A grid-following control strategy is adopted to track the first charging and discharging target power to control the charging and discharging of the electrochemical energy storage system.

[0218] Furthermore, in one embodiment of the present invention, the second control module 505 is specifically configured to:

[0219] Acquire a second SOC of the supercapacitor energy storage system, and determine a second charging coefficient and a second discharging coefficient corresponding to the supercapacitor energy storage system based on the second SOC;

[0220] Determine, by calculation, a second maximum discharge power and a second maximum charge power corresponding to the supercapacitor energy storage system in the current control time period according to a second charge coefficient and a second discharge coefficient corresponding to the supercapacitor energy storage system;

[0221] Determining a second target state of the supercapacitor energy storage system based on the high-frequency power, the second maximum charging power, and the second maximum discharging power;

[0222] Determine, according to the second target state, a second charging and discharging target power corresponding to the supercapacitor energy storage system in the current control time period;

[0223] The supercapacitor energy storage system is charged and discharged according to the second charge and discharge target power.

[0224] Furthermore, in one embodiment of the present invention, the second control module 505 is further configured to:

[0225] If the high-frequency power is greater than or equal to the second maximum charging power and less than or equal to the second maximum discharging power, determining that the second target state of the supercapacitor energy storage system is the fourth state;

[0226] If the high-frequency power is greater than the second maximum discharge power, determining that the second target state of the supercapacitor energy storage system is the fifth state;

[0227] If the high-frequency power is less than the second maximum charging power, it is determined that the second target state of the supercapacitor energy storage system is the sixth state.

[0228] Furthermore, in one embodiment of the present invention, the second control module 505 is further configured to:

[0229] If the second target state is the fourth state, the second charging and discharging target power corresponding to the supercapacitor energy storage system in the current control time period is high-frequency power;

[0230] If the second target state is the fifth state, the second charge and discharge target power corresponding to the supercapacitor energy storage system in the current control time period is the second maximum discharge power;

[0231] If the second target state is the sixth state, the second charging and discharging target power corresponding to the supercapacitor energy storage system in the current control time period is the second maximum charging power.

[0232] Furthermore, in one embodiment of the present invention, the second control module 505 is further configured to:

[0233] A grid-following control strategy is adopted to track the second charging and discharging target power to control the charging and discharging of the supercapacitor energy storage system.

[0234] According to the power smoothing output control device for a wind-storage fusion system of an embodiment of the present invention, the device can decompose the power deviation between the wind turbine smoothing output reference power and the actual output power to obtain the corresponding low-frequency power and high-frequency power, and control the charging and discharging of the electrochemical energy storage system and the supercapacitor energy storage system in the current control time period according to the low-frequency power and the high-frequency power, thereby reducing the harmonic content and improving the stability of wind power output, so that wind power can better participate in the dispatching arrangement of the power grid, promote large-scale grid connection and consumption of wind power, and ensure the stable operation of the power grid.

[0235] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0236] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

Claims

1. A power smoothing output control method for a wind-storage fusion system, characterized in that: The wind energy storage fusion system includes an electrochemical energy storage system and a supercapacitor energy storage system, and the method includes: Determine the smoothed output reference power and actual output power of the wind turbine generator set within a preset time period before the current control time period; Determining a power deviation between a smoothed output reference power and an actual output power of the wind turbine generator set; Decomposing the power deviation by a first-order low-pass filter to obtain corresponding low-frequency power and high-frequency power; Determine the smoothed output reference power of the wind turbine set in the next control time period according to the low-frequency power, and perform charge and discharge control on the electrochemical energy storage system in the current control time period; The supercapacitor energy storage system is controlled to charge and discharge during the current control time period according to the high-frequency power.

2. The method according to claim 1, characterized in that The step of determining the smoothed output reference power of the wind turbine generator set in the next control time period according to the low-frequency power, and controlling the charge and discharge of the electrochemical energy storage system in the current control time period, includes: Acquire a first state of charge SOC of the electrochemical energy storage system, and determine a first charging coefficient and a first discharging coefficient corresponding to the electrochemical energy storage system based on the first SOC; Determining, by calculation, a first maximum discharge power and a first maximum charge power corresponding to the electrochemical energy storage system in a current control time period according to a first charge coefficient and a first discharge coefficient corresponding to the electrochemical energy storage system; Determining a first target state of the electrochemical energy storage system based on the low-frequency power, the first maximum charging power, and the first maximum discharging power; Determine, according to the first target state, a smoothed output reference power of the wind turbine generator set in the next control time period and a first charge and discharge target power corresponding to the electrochemical energy storage system in the current control time period; The electrochemical energy storage system is controlled to charge and discharge according to the first charge and discharge target power.

3. The method according to claim 2, characterized in that The determining, based on the low-frequency power, the first maximum charging power, and the first maximum discharging power, of a first target state of the electrochemical energy storage system includes: If the low-frequency power is greater than or equal to the first maximum charging power and less than or equal to the first maximum discharging power, determining that the first target state of the electrochemical energy storage system is the first state; If the low-frequency power is greater than the first maximum discharge power, determining that the first target state of the electrochemical energy storage system is the second state; If the low-frequency power is less than the first maximum charging power, it is determined that the first target state of the electrochemical energy storage system is the third state.

4. The method according to claim 3, characterized in that Determining the smoothed output reference power of the wind turbine set in the next control time period and the first charge and discharge target power corresponding to the electrochemical energy storage system in the current control time period according to the first target state includes: If the first target state is the first state, the smoothed output reference power of the wind turbine generator set in the next control time period remains unchanged, and the first charge and discharge target power of the electrochemical energy storage system is the low-frequency power; If the first target state is the second state, the down-conversion coefficient of the wind turbine set in the next control time period is determined according to the first SOC, and the smoothed output reference power is determined according to the down-conversion coefficient; the first charge and discharge target power of the electrochemical energy storage system is the first maximum discharge power; If the first target state is the third state, the rising transformation coefficient of the wind turbine group in the next control time period is determined according to the first SOC, and the smooth output reference power is determined according to the rising transformation coefficient; the first charging and discharging target power of the electrochemical energy storage system is the first maximum charging power.

5. The method according to claim 2, characterized in that: The charging and discharging control of the electrochemical energy storage system according to the first charging and discharging target power includes: adopting a grid-based control strategy to track the first charging and discharging target power to control the charging and discharging of the electrochemical energy storage system.

6. The method according to claim 1, characterized in that The charging and discharging control of the supercapacitor energy storage system in the current control time period according to the high-frequency power includes: Acquire a second SOC of the supercapacitor energy storage system, and determine a second charging coefficient and a second discharging coefficient corresponding to the supercapacitor energy storage system based on the second SOC; Determine, by calculation, a second maximum discharge power and a second maximum charge power corresponding to the supercapacitor energy storage system in the current control time period according to the second charge coefficient and the second discharge coefficient corresponding to the supercapacitor energy storage system; Determining a second target state of the supercapacitor energy storage system based on the high-frequency power, the second maximum charging power, and the second maximum discharging power; Determine, according to the second target state, a second charging and discharging target power corresponding to the supercapacitor energy storage system in the current control time period; The supercapacitor energy storage system is controlled to charge and discharge according to the second charge and discharge target power.

7. The method according to claim 6, characterized in that The determining, based on the high-frequency power, the second maximum charging power, and the second maximum discharging power, of a second target state of the supercapacitor energy storage system includes: If the high-frequency power is greater than or equal to the second maximum charging power and less than or equal to the second maximum discharging power, determining that the second target state of the supercapacitor energy storage system is the fourth state; If the high-frequency power is greater than the second maximum discharge power, determining that the second target state of the supercapacitor energy storage system is the fifth state; If the high-frequency power is less than the second maximum charging power, it is determined that the second target state of the supercapacitor energy storage system is the sixth state.

8. The method according to claim 7, characterized in that Determining, according to the second target state, a second charging and discharging target power corresponding to the supercapacitor energy storage system in the current control time period includes: If the second target state is the fourth state, the second charging and discharging target power corresponding to the supercapacitor energy storage system in the current control time period is the high-frequency power; If the second target state is the fifth state, the second charge and discharge target power corresponding to the supercapacitor energy storage system in the current control time period is the second maximum discharge power; If the second target state is the sixth state, the second charging and discharging target power corresponding to the supercapacitor energy storage system in the current control time period is the second maximum charging power.

9. The method according to claim 6, characterized in that The charging and discharging control of the supercapacitor energy storage system according to the second charging and discharging target power includes: adopting a grid-based control strategy to track the second charging and discharging target power to control the charging and discharging of the supercapacitor energy storage system.

10. A power smoothing output control device for a wind-storage fusion system, characterized in that: The wind energy storage fusion system includes an electrochemical energy storage system and a supercapacitor energy storage system, and the device includes: The first determination module is used to determine the smoothed output reference power and the actual output power of the wind turbine generator set within a preset time period before the current control time period; A second determination module is used to determine a power deviation between the smoothed output reference power and the actual output power of the wind turbine generator set based on the smoothed output reference power and the actual output power; A processing module, used for decomposing the power deviation through a first-order low-pass filter to obtain corresponding low-frequency power and high-frequency power; A first control module, used to determine the smoothed output reference power of the wind turbine set in the next control time period according to the low-frequency power, and to perform charge and discharge control on the electrochemical energy storage system in the current control time period; The second control module is used to control the charging and discharging of the supercapacitor energy storage system in the current control time period according to the high-frequency power.

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