A power grid frequency regulation control method and device, electronic equipment and medium

Abstract

The application discloses a kind of power grid frequency regulation control method, device, electronic equipment and medium, it is related to new energy grid-connected system control technical field, the current frequency of photovoltaic power generation system is determined the sliding surface additional adjustment item of DC / DC converter, and then according to current first output voltage and current first output current, first duty cycle is determined, and according to the first duty cycle determined, DC / DC converter is driven, to determine the second duty cycle according to the current second output voltage of the DC / DC converter after driving, the current second output current of DC / AC converter and current third voltage, and according to the second duty cycle determined, DC / AC converter is driven, to adjust the frequency of the electric energy that DC / AC converter outputs to power grid, the present scheme can accurately control power grid frequency without installing additional energy storage module in photovoltaic power generation system, reduce cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of new energy grid-connected system control, and particularly relates to a power grid frequency regulation control method and device, electronic equipment and a medium. BACKGROUND

[0002] With the rapid development of science and technology and the advancement of industry, fossil energy is overexploited. In addition, the combustion of fossil energy produces a large amount of carbon dioxide, which causes serious pollution to the environment and violates the concept of green and sustainable development. In order to accelerate the realization of the goal of "carbon peak" and "carbon neutral", the use of new energy should be promoted. Photovoltaic power generation has become a rapidly developing new energy because of its clean and environmentally friendly, noiseless characteristics, and the cost of solar components is gradually decreasing. With the increasing penetration rate of photovoltaic power generation in the power grid, the frequency modulation capability of traditional generators in the power grid is insufficient to maintain frequency stability.

[0003] To solve the problem of frequency fluctuation caused by the increase of photovoltaic penetration rate, the traditional method is to install an energy storage system to adjust the frequency fluctuation, and the photovoltaic system operates at the maximum power point. However, the service life of current energy storage technology is generally lower than that of photovoltaic components, and the cost of energy storage modules is much higher than that of photovoltaic, which greatly increases the investment cost. SUMMARY

[0004] The purpose of the present application is to provide a power grid frequency regulation control method, device, electronic equipment and medium, which can accurately control the power grid frequency without installing additional energy storage modules in the photovoltaic power generation system, thereby reducing the cost.

[0005] To solve the above technical problems, the present application provides a power grid frequency regulation control method, comprising:

[0006] determining a sliding surface additional adjustment item corresponding to a DC / DC converter in the photovoltaic power generation system according to the current frequency of the photovoltaic power generation system;

[0007] determining a first duty ratio control quantity based on the current frequency, the sliding surface additional adjustment item, a current first output voltage and a current first output current of a photovoltaic array in the photovoltaic power generation system, and driving the DC / DC converter according to the first duty ratio control quantity;

[0008] determining a current second output voltage of the DC / DC converter under the driving of the first duty ratio control quantity;

[0009] determine a second duty cycle control quantity based on the current second output voltage, a current second output current of a filter in the photovoltaic power generation system corresponding to the DC / DC converter filtered by the filter, and a current third output voltage of the DC / AC converter filtered by the filter, and drive the DC / AC converter according to the second duty cycle control quantity to adjust a frequency of power output to the power grid by the DC / AC converter.

[0010] Optionally, the determining the additional adjustment item of the sliding mode surface corresponding to the DC / DC converter in the photovoltaic power generation system according to the current frequency of the photovoltaic power generation system comprises:

[0011] determining a frequency change rate of the photovoltaic power generation system within a preset time;

[0012] determining the additional adjustment item of the sliding mode surface corresponding to the DC / DC converter in the photovoltaic power generation system according to the frequency change rate and the current frequency.

[0013] Optionally, the determining the first duty cycle control quantity based on the current frequency, the additional adjustment item of the sliding mode surface, a current first output voltage and a current first output current of a photovoltaic array in the photovoltaic power generation system comprises:

[0014] determining a current frequency adjustment parameter by bringing the current frequency, the current first output voltage and the current first output current into a frequency adjustment parameter determination formula;

[0015] determining a current sliding mode surface control parameter according to the current frequency adjustment parameter, the additional adjustment item of the sliding mode surface and a sliding mode surface control parameter determination formula;

[0016] determining the first duty cycle control quantity based on the current sliding mode surface control parameter and the current first output voltage;

[0017] wherein the frequency adjustment parameter determination formula is:

[0018] H is the current frequency adjustment parameter, P PV , V PV , and I PV are the current frequency, the current first output voltage and the current first output current respectively;

[0019] the sliding mode surface control parameter determination formula is: PV S PV = α·H + λ·∫Hdt - ΔF;

[0020] wherein S PV is the current sliding mode surface control parameter, α and λ are a first weight factor and a second weight factor respectively, and ΔF is the additional adjustment item of the sliding mode surface.

[0021] Optionally, the first duty cycle control quantity is determined based on the sliding mode surface control parameter and the current first output voltage, including:

[0022] The sliding mode surface control parameter is brought into a photovoltaic voltage reference value determination formula to determine a current photovoltaic voltage reference value;

[0023] The first duty cycle control quantity is determined according to the current photovoltaic voltage reference value, the current first output voltage and a duty cycle control quantity determination formula;

[0024] The photovoltaic voltage reference value determination formula is V PVref = β · ∫ (ε · sgn (S PV ) + μ · S PV ) dt;

[0025] V PVref is the current photovoltaic voltage reference value, β, ε and μ are respectively a third weight factor, a fourth weight factor and a fifth weight factor, and sgn () is a sign function;

[0026] The duty cycle control quantity determination formula is:

[0027] The first duty cycle control quantity is D, and k pvD , k ivD are respectively a preset PI control proportional coefficient and an integral coefficient.

[0028] Optionally, the second duty cycle control quantity is determined based on the current second output voltage, a current second output current of a filter in a photovoltaic power generation system corresponding to a DC / AC converter of the DC / DC converter and a current third output voltage of the filter corresponding to the DC / AC converter, including:

[0029] The current reactive power of the photovoltaic power generation system is determined according to the current second output voltage and the current third output voltage;

[0030] The current q-axis current reference value of the DC / AC converter is determined through the current reactive power, a preset reactive power reference value and a q-axis current reference value determination formula;

[0031] The current d-axis current reference value of the DC / AC converter is determined based on the current second output voltage, a preset voltage reference value and a d-axis current reference value determination formula;

[0032] determine a current q-axis voltage reference value and a current d-axis voltage reference value of the DC / AC converter according to the current q-axis current reference value, the current d-axis current reference value, the current third output voltage and the current second output current;

[0033] determine the second duty ratio control quantity based on the current q-axis voltage reference value and the current d-axis voltage reference value;

[0034] wherein the q-axis current reference value confirmation formula is

[0035] i qref is a current q-axis current reference value of the DC / AC converter, Q is the current reactive power, Q ref is a preset reactive power reference value, k pQ , k iQ are respectively a proportional coefficient and an integral coefficient of the reactive power PI control, and s is a sixth weight factor;

[0036] the d-axis current reference value confirmation formula is:

[0037] wherein i dref is a current d-axis current reference value of the DC / AC converter, V dc is the current second output voltage, V dcref is the preset voltage reference value, k pu , k iu are respectively a proportional system and an integral coefficient of the direct current chain voltage PI control.

[0038] Optionally, the determining of the current q-axis voltage reference value and the current d-axis voltage reference value of the DC / AC converter according to the current q-axis current reference value, the current d-axis current reference value, the current third output voltage and the current second output current comprises:

[0039] determining an inductance of the filter;

[0040] determining the current q-axis voltage reference value and the current d-axis voltage reference value of the DC / AC converter based on the inductance, the current q-axis current reference value, the current d-axis current reference value, the current third output voltage and the current second output current.

[0041] Optionally, the determining of the current q-axis voltage reference value and the current d-axis voltage reference value of the DC / AC converter based on the inductance, the current q-axis current reference value, the current d-axis current reference value, the current third output voltage and the current second output current comprises:

[0042] determine the q-axis voltage reference value according to the inductance, the current d-axis current reference value, the current second output current corresponding d-axis current, the current third output voltage corresponding q-axis voltage and a q-axis voltage reference value confirmation formula;

[0043] determine the d-axis voltage reference value according to the inductance, the current d-axis current reference value, the current third output voltage corresponding q-axis current, the current second output current corresponding d-axis current, the current third output voltage corresponding d-axis voltage and a d-axis voltage reference value confirmation formula;

[0044] wherein the q-axis voltage reference value confirmation formula is:

[0045] v oqref is the q-axis voltage reference value, v q is the current third output voltage corresponding q-axis voltage, i q is the current second output current corresponding q-axis current, L f is the inductance, i d is the current second output current corresponding d-axis current, k pi , k ii are respectively a proportional coefficient and an integral coefficient of preset PI control, and ω is a seventh weight factor;

[0046] the d-axis voltage reference value confirmation formula is:

[0047] wherein v odref is the d-axis voltage reference value.

[0048] To solve the above technical problems, the application further provides a control device for grid frequency adjustment, comprising:

[0049] a first determination unit configured to determine a sliding mode surface additional adjustment item corresponding to a DC / DC converter in a photovoltaic power generation system according to a current frequency of the photovoltaic power generation system;

[0050] a second determination unit configured to determine a first duty cycle control quantity based on the current frequency, the sliding mode surface additional adjustment item, a current first output voltage and a current first output current of a photovoltaic array in the photovoltaic power generation system, and drive the DC / DC converter according to the first duty cycle control quantity;

[0051] a third determination unit configured to determine a current second output voltage of the DC / DC converter under the driving of the first duty cycle control quantity;

[0052] A fourth determining unit is configured to determine a second duty cycle control quantity based on the current second output voltage, a current second output current of the DC / DC converter corresponding to a DC / AC converter filtered by a filter, and a current third output voltage of the DC / AC converter filtered by the filter, and drive the DC / AC converter according to the second duty cycle control quantity to adjust the frequency of the power output by the DC / AC converter to the power grid.

[0053] To solve the above technical problems, the application further provides an electronic device, comprising:

[0054] a memory configured to store a computer program;

[0055] a processor configured to execute the computer program to implement the steps of the power grid frequency adjustment control method.

[0056] To solve the above technical problems, the application further provides a computer readable storage medium, wherein the computer readable storage medium stores a computer program, and the computer program is executed by a processor to implement the steps of the power grid frequency adjustment control method.

[0057] The application aims to provide a power grid frequency adjustment control method, device, electronic device, and medium. The current frequency of a photovoltaic power generation system is determined to obtain a sliding mode surface additional adjustment item of a DC / DC converter. Then, a first duty cycle is determined according to a current first output voltage and a current first output current. The DC / DC converter is driven according to the determined first duty cycle. A second duty cycle is determined according to a current second output voltage of the driven DC / DC converter, a current second output current of a DC / AC converter, and a current third voltage. The DC / AC converter is driven according to the determined second duty cycle to adjust the frequency of the power output by the DC / AC converter to the power grid. The application can accurately control the power grid frequency without installing an additional energy storage module in the photovoltaic power generation system, thereby reducing the cost. BRIEF DESCRIPTION OF DRAWINGS

[0058] To make the technical solutions of the embodiments of the application or the prior art clearer, the accompanying drawings needed in the embodiments or prior art description will be briefly introduced. Obviously, the accompanying drawings in the following description are only some embodiments of the application, and for those skilled in the art, other drawings can be obtained without creative effort based on the provided drawings.

[0059] Figure 1 A process flow chart of the power grid frequency adjustment control method provided by the application;

[0060] Figure 2A control principle block diagram of a photovoltaic system adaptive participation frequency regulation is provided for the present application.

[0061] Figure 3 A photovoltaic array equivalent current source model is provided for the present application.

[0062] Figure 4 A control principle diagram of a photovoltaic system DC / DC converter is provided for the present application.

[0063] Figure 5 A control principle diagram of a photovoltaic system DC / AC converter is provided for the present application.

[0064] Figure 6 A frequency simulation waveform diagram when the load changes is provided for the present application.

[0065] Figure 7 A frequency simulation waveform diagram when the light intensity changes is provided for the present application.

[0066] Figure 8 A structural schematic diagram of a power grid frequency regulation control device is provided for the present application.

[0067] Figure 9 A structural schematic diagram of an electronic device is provided for the present application. DETAILED DESCRIPTION

[0068] The core of the present application is to provide a power grid frequency regulation control method, device, electronic equipment and medium, which can accurately control the power grid frequency without installing additional energy storage modules in the photovoltaic power generation system, thereby reducing the cost.

[0069] Please refer to Figure 1 , Figure 1 A process flow chart of a power grid frequency regulation control method is provided for the present application. The method comprises:

[0070] S11: determining a sliding surface additional adjustment item corresponding to a DC / DC converter in the photovoltaic power generation system according to the current frequency of the photovoltaic power generation system;

[0071] S12: determining a first duty cycle control quantity based on the current frequency, the sliding surface additional adjustment item, the current first output voltage and the current first output current of the photovoltaic array in the photovoltaic power generation system, and driving the DC / DC converter according to the first duty cycle control quantity;

[0072] S13: determining the current second output voltage of the DC / DC converter under the driving of the first duty cycle control quantity;

[0073] S14: determining a second duty cycle control quantity based on the current second output voltage, the current second output current filtered by the filter in the photovoltaic power generation system and the current third output voltage filtered by the filter of the DC / AC converter corresponding to the DC / DC converter of the photovoltaic power generation system, and driving the DC / AC converter according to the second duty cycle control quantity, so as to adjust the frequency of the electric energy output to the power grid by the DC / AC converter.

[0074] In the present application, considering that the penetration rate of photovoltaic in the power grid is increasing, the frequency modulation capability of the traditional generator in the power grid is insufficient, and it is difficult to maintain the frequency stability, therefore, the additional adjustment item of the sliding mode surface corresponding to the DC / DC converter in the photovoltaic power generation system is determined according to the current frequency of the photovoltaic power generation system, then the first duty cycle control quantity is determined according to the determined additional adjustment item of the sliding mode surface, the current frequency, the current first output voltage and the current first output current of the photovoltaic array in the photovoltaic power generation system, then the DC / DC converter is driven according to the first duty cycle control quantity, the current second output voltage of the DC / DC converter under the driving of the first duty cycle control quantity is determined, finally, the second duty cycle control quantity is determined based on the determined current second output voltage, the current second output current filtered by the filter in the photovoltaic power generation system and the current third output voltage filtered by the filter of the DC / AC converter corresponding to the DC / DC converter, and the DC / AC converter is driven according to the second duty cycle control quantity, so that the frequency of the electric energy output to the power grid by the driven DC / AC converter is the frequency conforming to the current frequency change of the current photovoltaic power generation system, so that the frequency output to the power grid is kept stable, in addition, the present application can accurately control the frequency of the power grid without installing an additional energy storage module in the photovoltaic power generation system, thereby reducing the cost.

[0075] It should be noted that the photovoltaic power generation grid-connected system includes a photovoltaic array, a direct current side capacitor, a DC / DC (Direct Current / Direct Current) converter connected with the photovoltaic, a DC / AC (Direct Current / Alternating Current) three-phase inverter connected with the power grid side, an alternating current side filter, a transmission line and a corresponding control system, and the control principle of the photovoltaic system self-adapting to participate in frequency regulation is as shown in Figure 2 The photovoltaic array is a nonlinear device, which can be equivalent to a current source model, as shown in Figure 3 , wherein I pl represents the photocurrent, R1 and R2 represent the equivalent series and parallel resistances of the photovoltaic array respectively. The inductance and capacitance of the alternating current side filter are defined as L f and C f respectively. The quantities to be measured include the voltage V PV and the current IPV , the photovoltaic array outputs voltage V dc , the three-phase voltage v abc and current i abc after conversion by the DC / AC inverter and through the filter.

[0076] It should be further noted that the photovoltaic power generation system adopts a two-stage structure, wherein the control loop of the DC / DC converter includes a voltage control loop, a power control loop and an adaptive frequency regulation control loop, and the control loop of the DC / AC converter includes a current control loop and a DC link voltage / reactive power control loop. For the control strategy of the DC / DC converter, first, a PI vector control method of the voltage control loop is designed, and the output result is duty ratio D, which drives the DC / DC converter through PWM (Pulse Width Modulation) modulation. The reference voltage input of the voltage control loop is the output of the power control loop; second, a power control strategy based on sliding mode control (SMC) is designed, and the input is the output of the adaptive frequency regulation control loop; finally, a fuzzy control-based adaptive frequency regulation control strategy is designed according to frequency fluctuation. For the control strategy of the DC / AC converter, the goal is to stabilize the DC link voltage and regulate the reactive power, and each control loop adopts a PI (Proportion Integration) vector control method, and the final output reference voltage drives the three-phase DC / AC converter through PWM modulation.

[0077] It should be further noted that the solution of the present application is to pulse modulate the DC / DC converter and the DC / AC converter according to the current frequency change of the photovoltaic power generation system, and the implementation of the modulation process can establish five controllers, namely, an adaptive frequency regulation controller of the DC / DC converter, a power loop controller of the DC / DC converter based on sliding mode control, a power loop controller of the DC / DC converter based on PI control, a power loop controller of the DC / AC converter based on DC link voltage / reactive power, and a current loop controller of the DC / AC converter, as shown in Figure 2 .

[0078] It also needs to be explained that the application controls the photovoltaic system to participate in the frequency regulation of the power grid and maintain the frequency stability without using the energy storage system to participate in the frequency regulation, thereby reducing the investment cost.The application adopts the fuzzy control, the sliding mode control and the PI control, and each control loop cooperates to realize that the photovoltaic system adaptively adjusts the output power according to the frequency fluctuation and participates in the frequency regulation of the power grid.Due to the characteristics of the sliding mode control and the fuzzy control, the designed control method can well meet the requirements of the stability and the high control performance of the system.The control method designed in the application does not need the detailed model of the photovoltaic and the irradiance sensor, and is easy to realize.

[0079] The embodiment provides a control method for grid frequency regulation, a sliding mode surface additional adjustment item of a DC / DC converter is determined through a current frequency of a photovoltaic power generation system, then a first duty cycle is determined according to a current first output voltage and a current first output current, the DC / DC converter is driven according to the determined first duty cycle, a second duty cycle is determined according to a current second output voltage of the driven DC / DC converter, a current second output current of a DC / AC converter and a current third voltage, and the DC / AC converter is driven according to the determined second duty cycle, so as to adjust the frequency of the electric energy output to the power grid by the DC / AC converter.The scheme can accurately control the grid frequency without installing an additional energy storage module in the photovoltaic power generation system, thereby reducing the cost.

[0080] On the basis of the above embodiment:

[0081] As an optional embodiment, the sliding mode surface additional adjustment item corresponding to the DC / DC converter in the photovoltaic power generation system is determined according to the current frequency of the photovoltaic power generation system, and the method comprises the steps that:

[0082] The frequency change rate of the photovoltaic power generation system within a preset time is determined.

[0083] The sliding mode surface additional adjustment item corresponding to the DC / DC converter in the photovoltaic power generation system is determined according to the frequency change rate and the current frequency.

[0084] In the application, the specific process of determining the sliding mode surface additional adjustment item corresponding to the DC / DC converter in the photovoltaic power generation system according to the current frequency of the photovoltaic power generation system comprises the steps that the frequency change rate of the photovoltaic power generation system within a preset time is determined first, and then the sliding mode surface additional adjustment item corresponding to the DC / DC converter in the photovoltaic power generation system is determined according to the determined frequency change rate and the current frequency, thereby improving the accuracy of the determination process of the sliding mode surface additional adjustment item.

[0085] It should be noted that the additional adjustment item ΔF of the sliding surface is obtained by using fuzzy control, and the specific implementation method is that the input of the fuzzy controller is the current frequency and the frequency change df / dt, and the output is the additional adjustment item ΔF of the sliding surface. When the frequency fluctuates upwards (not exceeding the maximum frequency allowed by the system), ΔF should be increased, and the photovoltaic array will reduce the output power; when the frequency fluctuates downwards (not lower than the minimum frequency allowed by the system), ΔF should be reduced, and the photovoltaic array will increase the output power. Accordingly, the correspondence between the input and output of the fuzzy controller and the membership function are established, and the additional adjustment item of the sliding surface is adaptively adjusted according to the change of the input frequency.

[0086] As an optional embodiment, the first duty cycle control quantity is determined based on the current frequency, the additional adjustment item of the sliding surface, the current first output voltage and the current first output current of the photovoltaic array in the photovoltaic power generation system, and includes:

[0087] The current frequency, the current first output voltage and the current first output current are brought into the frequency adjustment parameter determination formula to determine the current frequency adjustment parameter;

[0088] The current frequency adjustment parameter, the additional adjustment item of the sliding surface and the sliding surface control parameter determination formula are used to determine the current sliding surface control parameter;

[0089] The first duty cycle control quantity is determined based on the sliding surface control parameter and the current first output voltage;

[0090] The frequency adjustment parameter determination formula is:

[0091] H is the current frequency adjustment parameter, P PV , V PV , I PV are the current frequency, the current first output voltage and the current first output current respectively;

[0092] The sliding surface control parameter determination formula is: PV S PV = α·H + λ·∫Hdt - ΔF;

[0093] Wherein, S PV is the current sliding surface control parameter, α and λ are the first weight factor and the second weight factor respectively, and ΔF is the additional adjustment item of the sliding surface.

[0094] In the present application, the specific process of determining the first duty ratio control quantity based on the current frequency, the additional adjustment term of the sliding surface, the current first output voltage and the current first output current of the photovoltaic array in the photovoltaic power generation system is as follows: first, the current frequency, the current first output voltage and the current first output current are brought into the frequency adjustment parameter determination formula to determine the current frequency adjustment parameter, then the determined current frequency adjustment parameter and the additional adjustment term of the sliding surface are brought into the sliding surface control parameter determination formula, so that the current sliding surface control parameter can be calculated, and finally the first duty ratio control quantity can be accurately determined based on the sliding surface control parameter and the current first output voltage.

[0095] As an optional embodiment, determining the first duty ratio control quantity based on the sliding surface control parameter and the current first output voltage comprises:

[0096] bringing the sliding surface control parameter into the photovoltaic voltage reference value confirmation formula to determine the current photovoltaic voltage reference value;

[0097] determining the first duty ratio control quantity according to the current photovoltaic voltage reference value, the current first output voltage and the duty ratio control quantity confirmation formula;

[0098] wherein the photovoltaic voltage reference value confirmation formula is V PVref = β · ∫ (ε · sgn (S PV ) + μ · S PV ) dt;

[0099] V PVref is the current photovoltaic voltage reference value, β, ε and μ are respectively a third weight factor, a fourth weight factor and a fifth weight factor, and sgn () is a sign function;

[0100] the duty ratio control quantity confirmation formula is:

[0101] wherein D is the first duty ratio control quantity, k pvD and k ivD are respectively a preset PI control proportional coefficient and an integral coefficient.

[0102] In the present application, the specific process of determining the first duty ratio control quantity based on the sliding surface control parameter and the current first output voltage is as follows: first, the sliding surface control parameter is brought into the photovoltaic voltage reference value confirmation formula to determine the current photovoltaic voltage reference value, then the first duty ratio control quantity is determined according to the determined current photovoltaic voltage reference value, the current first output voltage and the duty ratio control quantity confirmation formula, thereby improving the accuracy of the first duty ratio control quantity determination process.

[0103] It should be noted that when S PV = 0, the photovoltaic system works at the maximum power point, and when S PVWhen > 0, the system works on the left side of the maximum power point; when PV When < 0, the system works on the right side of the maximum power point. The first derivative of the output voltage reference value of the power controller based on the sliding mode control is The relationship between the first derivative of the sliding mode surface is: The chattering problem caused by inertia and hysteresis is the main drawback of the sliding mode control. In order to improve the convergence speed, an exponential reaching law is designed as: Wherein, is the first derivative of S PV , and the control principle diagram of the DC / DC converter of the photovoltaic system is shown in Figure 4 .

[0104] As an optional embodiment, the second duty cycle control quantity is determined based on the current second output voltage, the current second output current filtered by a filter in the photovoltaic power generation system and the current third output voltage filtered by the filter in the DC / AC converter corresponding to the DC / DC converter, and the second duty cycle control quantity comprises:

[0105] The current reactive power of the photovoltaic power generation system is determined according to the current second output current and the current third output voltage;

[0106] The current q-axis current reference value of the DC / AC converter is determined through the current reactive power, the preset reactive power reference value and the q-axis current reference value confirmation formula;

[0107] The current d-axis current reference value of the DC / AC converter is determined based on the current second output voltage, the preset voltage reference value and the d-axis current reference value confirmation formula;

[0108] The current q-axis voltage reference value and the current d-axis voltage reference value of the DC / AC converter are determined according to the current q-axis current reference value, the current d-axis current reference value, the current third output voltage and the current second output current;

[0109] The second duty cycle control quantity is determined based on the current q-axis voltage reference value and the current d-axis voltage reference value;

[0110] Wherein, the q-axis current reference value confirmation formula is

[0111] i qref is the current q-axis current reference value of the DC / AC converter, Q is the current reactive power, Q ref is the preset reactive power reference value, k pQ , k iQ are the proportional coefficient and the integral coefficient of the reactive power PI control respectively, and s is the sixth weight factor;

[0112] The d-axis current reference value confirmation formula is:

[0113] Wherein, i dref is the current d-axis current reference value of the DC / AC converter, V dc is the current second output voltage, V dcref is the preset voltage reference value, k pu , k iu are the proportional system and integral coefficient of the DC link voltage PI control, respectively.

[0114] In the present application, the specific process of determining the second duty ratio control quantity based on the current second output voltage, the current second output current of the DC / DC converter corresponding to the DC / AC converter filtered by the filter in the photovoltaic power generation system, and the current third output voltage of the DC / AC converter filtered by the filter is as follows: first, the current reactive power of the photovoltaic power generation system is determined according to the current second output current and the current third output voltage, and then the current q-axis current reference value of the DC / AC converter is determined through the current reactive power, the preset reactive power reference value, and the q-axis current reference value confirmation formula. Similarly, the current d-axis current reference value of the DC / AC converter can be determined based on the current second output voltage, the preset voltage reference value, and the d-axis current reference value confirmation formula. Then, the current q-axis voltage reference value and the current d-axis voltage reference value of the DC / AC converter are determined according to the determined current q-axis current reference value, the current d-axis current reference value, the current third output voltage, and the current second output current. Finally, the second duty ratio control quantity can be accurately determined based on the current q-axis voltage reference value and the current d-axis voltage reference value.

[0115] As an optional embodiment, the current q-axis voltage reference value and the current d-axis voltage reference value of the DC / AC converter are determined according to the current q-axis current reference value, the current d-axis current reference value, the current third output voltage, and the current second output current, which includes:

[0116] determining the inductance of the filter;

[0117] determining the current q-axis voltage reference value and the current d-axis voltage reference value of the DC / AC converter based on the inductance, the current q-axis current reference value, the current d-axis current reference value, the current third output voltage, and the current second output current.

[0118] In the application, the specific process for determining the current q-axis voltage reference value and the current d-axis voltage reference value of the DC / AC converter according to the current q-axis current reference value, the current d-axis current reference value, the current third output voltage and the current second output current is: first, determining the inductance of the filter, and then determining the current q-axis voltage reference value and the current d-axis voltage reference value of the DC / AC converter based on the inductance, the current q-axis current reference value, the current d-axis current reference value, the current third output voltage and the current second output current, so that the current q-axis voltage reference value and the current d-axis voltage reference value of the DC / AC converter can be accurately determined, and the reliability of the scheme is improved.

[0119] As an optional embodiment, the current q-axis voltage reference value and the current d-axis voltage reference value of the DC / AC converter are determined based on the inductance, the current q-axis current reference value, the current d-axis current reference value, the current third output voltage and the current second output current, and the method comprises the steps of:

[0120] determining the q-axis voltage reference value based on the inductance, the current q-axis current reference value, the q-axis current corresponding to the current second output current, the d-axis current corresponding to the current second output current, the q-axis voltage corresponding to the current third output voltage and the q-axis voltage reference value determination formula;

[0121] determining the d-axis voltage reference value based on the inductance, the current d-axis current reference value, the q-axis current corresponding to the current third output voltage, the d-axis current corresponding to the current second output current, the d-axis voltage corresponding to the current third output voltage and the d-axis voltage reference value determination formula;

[0122] wherein the q-axis voltage reference value determination formula is:

[0123] v oqref is the q-axis voltage reference value, v q is the q-axis voltage corresponding to the current third output voltage, i q is the q-axis current corresponding to the current second output current, L f is the inductance, i d is the d-axis current corresponding to the current second output current, k pi , k ii are respectively a proportional coefficient and an integral coefficient of a preset PI control, and ω is a seventh weight factor;

[0124] the d-axis voltage reference value determination formula is:

[0125] wherein v odref is the d-axis voltage reference value.

[0126] In the application, the determination process of the current q-axis voltage reference value and the current d-axis voltage reference value of the DC / AC converter based on the inductance, the current q-axis current reference value, the current d-axis current reference value, the current third output voltage and the current second output current is as follows: first, the q-axis voltage reference value is determined based on the inductance, the current q-axis current reference value, the q-axis current corresponding to the current second output current, the d-axis current corresponding to the current second output current, the q-axis voltage corresponding to the current third output voltage and the q-axis voltage reference value determination formula; then, the inductance, the current d-axis current reference value, the q-axis current corresponding to the current second output current, the d-axis current corresponding to the current second output current, the d-axis voltage corresponding to the current third output voltage are brought into the d-axis voltage reference value determination formula, and the d-axis voltage reference value is determined through calculation, thereby improving the accuracy of the d-axis voltage reference value determination process.

[0127] It should be noted that i d and i q are the d-axis and q-axis current values of the three-phase current after the filter on the AC side of the DC / AC converter and obtained through the Park transformation, v d and v q are the d-axis and q-axis voltage values of the three-phase voltage after the filter on the AC side of the DC / AC converter and obtained through the Park transformation, and the control principle diagram of the photovoltaic system DC / AC converter is as shown in Figure 5 .

[0128] It should be further noted that the simulation of the photovoltaic system is carried out under the conditions of load change and light intensity change, and the frequency fluctuation simulation waveform is as shown in Figure 6 and Figure 7 . It can be seen from the simulation waveform that the control method designed in the application can effectively realize the adaptive participation of the photovoltaic system in the grid frequency regulation and maintain the stability of the grid frequency.

[0129] Please refer to Figure 8 , Figure 8 for the structural schematic diagram of a control device for grid frequency regulation provided by the application. The device comprises:

[0130] The first determination unit 11 is configured to determine the additional adjustment item of the sliding mode surface corresponding to the DC / DC converter in the photovoltaic power generation system according to the current frequency of the photovoltaic power generation system.

[0131] The second determination unit 12 is configured to determine the first duty ratio control quantity based on the current frequency, the additional adjustment item of the sliding mode surface, the current first output voltage and the current first output current of the photovoltaic array in the photovoltaic power generation system, and drive the DC / DC converter according to the first duty ratio control quantity.

[0132] The third determination unit 13 is configured to determine the current second output voltage of the DC / DC converter under the driving of the first duty ratio control quantity.

[0133] The fourth determining unit 14 is configured to determine a second duty ratio control quantity based on the current second output voltage, the current second output current filtered by the filter of the DC / AC converter corresponding to the DC / DC converter, and the current third output voltage filtered by the filter of the DC / AC converter, and drive the DC / AC converter according to the second duty ratio control quantity to adjust the frequency of the power output by the DC / AC converter to the power grid.

[0134] The power grid frequency regulation control device provided by the embodiment corresponds to the method, and has the same beneficial effects as the method. Therefore, the embodiments of the power grid frequency regulation control device are described in the embodiments of the method, and are not described herein.

[0135] Please refer to Figure 9 , Figure 9 A structural schematic diagram of an electronic device provided by the present application. The electronic device comprises:

[0136] The memory 20 is configured to store a computer program.

[0137] The processor 21 is configured to execute the computer program to implement the steps of the power grid frequency regulation control method.

[0138] The electronic device provided by the embodiment can include, but is not limited to, a smart phone, a tablet computer, a notebook computer, or a desktop computer, etc.

[0139] The processor 21 can include one or more processing cores, such as a 4-core processor, an 8-core processor, etc. The processor 21 can be implemented in at least one of a hardware form of a digital signal processor (DSP), a field-programmable gate array (FPGA), and a programmable logic array (PLA). The processor 21 can also include a main processor and a coprocessor. The main processor is a processor for processing data in an awake state, also known as a central processing unit (CPU). The coprocessor is a low-power processor for processing data in a standby state. In some embodiments, the processor 21 can be integrated with a graphics processor (GPU) that is responsible for rendering and drawing the content to be displayed by the display screen. In some embodiments, the processor 21 can also include an artificial intelligence (AI) processor that is configured to process machine learning-related computing operations.

[0140] The memory 20 can include one or more computer-readable storage media. The computer-readable storage media can be non-transitory. The memory 20 can also include high-speed random access memory and can include non-volatile memory, such as one or more magnetic disk storage devices, flash memory devices. In this embodiment, the memory 20 is at least used to store the following computer program 201, wherein the computer program is loaded and executed by the processor 21, and can realize the related steps of the power grid frequency regulation control method disclosed in any of the foregoing embodiments. In addition, the resources stored by the memory 20 can also include an operating system 202 and data 203, and the storage mode can be temporary storage or permanent storage. The operating system 202 can include Windows, Unix, Linux, etc. The data 203 can include but is not limited to the power grid frequency regulation control method, etc.

[0141] In some embodiments, the electronic device can further include a display screen 22, an input / output interface 23, a communication interface 24, a power supply 25, and a communication bus 26.

[0142] Those skilled in the art can understand that the structure shown in the above embodiments does not constitute a limitation on the electronic device, and can include more or fewer components than those shown in the figure. Figure 9

[0143] The purpose of the present embodiment is to provide an electronic device, wherein the memory 20 is used to store a computer program, and the processor 21 is used to execute the computer program to realize the steps of the power grid frequency regulation control method as described above, so that the process of control is more efficient and accurate.

[0144] The present application also provides an embodiment of a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and the computer program is executed by a processor to realize the steps of the power grid frequency regulation control method as described above.

[0145] It can be understood that if the method in the above embodiments is realized in the form of a software function unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solutions of the present application essentially or the part that contributes to the prior art or the whole or part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium, and executes all or part of the steps of the method of each embodiment of the present application. The foregoing storage medium includes: a U disk, a mobile hard disk, a read-only memory (Read-Only Memory, ROM), a random access memory (Random Access Memory, RAM), a magnetic disk or an optical disk, and various media that can store program codes. ​

[0146] The computer readable storage medium provided by the embodiments has the same beneficial effects as the method, and therefore the embodiments of the computer readable storage medium are described in the description of the embodiments of the method, which will not be described here in detail.

[0147] It should be noted that the relative terms, such as first and second, and the like, are used herein only to distinguish one entity or action from another, and do not necessarily require or imply any actual such relationship or order between or among these entities or actions. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, so that a process, method, article, or apparatus that comprises a list of elements does not include only those elements, but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without more limitations, an element defined by the statement "comprising a" does not exclude the existence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0148] The above description of disclosed embodiments enables a person skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A control method of grid frequency regulation, characterized in that, The method comprises the following steps: determining a sliding surface additional adjustment item corresponding to a DC / DC converter in a photovoltaic power generation system according to a current frequency of the photovoltaic power generation system; determining a first duty ratio control quantity based on the current frequency, the sliding surface additional adjustment item, a current first output voltage and a current first output current of a photovoltaic array in the photovoltaic power generation system, and driving the DC / DC converter according to the first duty ratio control quantity; determining a current second output voltage of the DC / DC converter under the driving of the first duty ratio control quantity; determining a second duty ratio control quantity based on the current second output voltage, a current second output current of a DC / AC converter corresponding to the DC / DC converter filtered by a filter in the photovoltaic power generation system, and a current third output voltage of the DC / AC converter filtered by the filter, and driving the DC / AC converter according to the second duty ratio control quantity to adjust the frequency of the electric energy output to a power grid by the DC / AC converter; wherein the determination of the first duty ratio control quantity based on the current frequency, the sliding surface additional adjustment item, the current first output voltage and the current first output current of the photovoltaic array in the photovoltaic power generation system comprises: determining a current frequency adjustment parameter by bringing the current frequency, the current first output voltage and the current first output current into a frequency adjustment parameter determination formula; determining a current sliding surface control parameter according to the current frequency adjustment parameter, the sliding surface additional adjustment item and a sliding surface control parameter determination formula; determining the first duty ratio control quantity based on the sliding surface control parameter and the current first output voltage; The frequency adjustment parameter determination formula is: ; for the current frequency adjustment parameter, , , the current frequency, the current first output voltage, and the current first output current, respectively. The sliding mode surface control parameter determination formula is: ; wherein, is the current sliding mode surface control parameter, and are a first and second weight factor, respectively, is the sliding mode surface additional adjustment term; wherein the determination of the first duty ratio control quantity based on the sliding surface control parameter and the current first output voltage comprises: determining a current photovoltaic voltage reference value by bringing the sliding surface control parameter into a photovoltaic voltage reference value confirmation formula; determining the first duty ratio control quantity according to the current photovoltaic voltage reference value, the current first output voltage and a duty ratio control quantity confirmation formula; The photovoltaic voltage reference value confirmation formula is: ; is the current photovoltaic voltage reference value, , and are a third, fourth and fifth weight factor, respectively, is a sign function; The duty cycle control amount confirmation formula is: ; wherein, is the first duty cycle control amount, , are respectively a proportional coefficient and an integral coefficient of the preset PI control.

2. The control method of grid frequency regulation of claim 1, wherein, the determination of the sliding surface additional adjustment item corresponding to the DC / DC converter in the photovoltaic power generation system according to the current frequency of the photovoltaic power generation system comprises: determining a frequency change rate of the photovoltaic power generation system within a preset time; determining the sliding surface additional adjustment item corresponding to the DC / DC converter in the photovoltaic power generation system according to the frequency change rate and the current frequency.

3. A control method of grid frequency regulation according to claim 1 or 2, characterized in that, the determination of the second duty ratio control quantity based on the current second output voltage, the current second output current of the DC / AC converter filtered by the filter in the photovoltaic power generation system, and the current third output voltage of the DC / AC converter filtered by the filter comprises: determining a current reactive power of the photovoltaic power generation system according to the current second output current and the current third output voltage; determining a current q-axis current reference value of the DC / AC converter through a current reactive power, a preset reactive power reference value and a q-axis current reference value confirmation formula; determine a current d-axis current reference value of the DC / AC converter based on the current second output voltage, a preset voltage reference value and a d-axis current reference value confirmation formula; determine a current q-axis voltage reference value and a current d-axis voltage reference value of the DC / AC converter according to the current q-axis current reference value, the current d-axis current reference value, the current third output voltage and the current second output current; determine the current q-axis voltage reference value and the current d-axis voltage reference value based on the current q-axis voltage reference value and the current d-axis voltage reference value; The q-axis current reference value confirmation formula is ; is a current q-axis current reference value of the DC / AC converter, is the current reactive power, is a preset reactive power reference value, , are a proportional coefficient and an integral coefficient of the reactive power PI control, respectively, is a sixth weight factor; The d-axis current reference value confirmation formula is: ; wherein, is a current d-axis current reference value of the DC / AC converter, is the current second output voltage of the DC / AC converter, is the preset voltage reference value of the DC / AC converter, , are respectively a proportional system and an integral coefficient of the DC link voltage PI control.

4. The control method of grid frequency regulation as claimed in claim 3, characterized in that, determine a current q-axis voltage reference value and a current d-axis voltage reference value of the DC / AC converter according to the current q-axis current reference value, the current d-axis current reference value, the current third output voltage and the current second output current, comprising: determine the inductance of the filter; determine the current q-axis voltage reference value and the current d-axis voltage reference value of the DC / AC converter based on the inductance, the current q-axis current reference value, the current d-axis current reference value, the current third output voltage and the current second output current.

5. A control method of grid frequency regulation as claimed in claim 4, characterized in that, determine the current q-axis voltage reference value and the current d-axis voltage reference value of the DC / AC converter based on the inductance, the current q-axis current reference value, the current d-axis current reference value, the current third output voltage and the current second output current, comprising: determine the q-axis voltage reference value based on the inductance, the current q-axis current reference value, a q-axis current corresponding to the current second output current, a d-axis current corresponding to the current second output current, a q-axis voltage corresponding to the current third output voltage and a q-axis voltage reference value confirmation formula; determine the d-axis voltage reference value according to the inductance, the current d-axis current reference value, a q-axis current corresponding to the current third output voltage, a d-axis current corresponding to the current second output current, a d-axis voltage corresponding to the current third output voltage and a d-axis voltage reference value confirmation formula; The q-axis voltage reference value confirmation formula is: ; is the q-axis voltage corresponding to the current second output current, is the q-axis voltage corresponding to the current third output voltage, is the q-axis current corresponding to the current second output current, is the inductance, is the d-axis current corresponding to the current second output current, , are respectively a proportional coefficient and an integral coefficient of preset PI control, is a seventh weight factor; The d-axis voltage reference value confirmation formula is: ; wherein, is the d-axis voltage reference value, is the d-axis voltage corresponding to the current third output voltage.

6. A control device for grid frequency regulation, characterized in that comprising: a first determination unit configured to determine a sliding surface additional adjustment item corresponding to a DC / DC converter in a photovoltaic power generation system according to a current frequency of the photovoltaic power generation system; a second determination unit configured to determine a first duty cycle control quantity based on the current frequency, the sliding surface additional adjustment item, a current first output voltage and a current first output current of a photovoltaic array in the photovoltaic power generation system, and drive the DC / DC converter according to the first duty cycle control quantity; a third determination unit configured to determine a current second output voltage of the DC / DC converter under the driving of the first duty cycle control quantity; a fourth determination unit configured to determine a second duty cycle control quantity based on the current second output voltage, a current second output current of a DC / AC converter corresponding to the DC / DC converter after being filtered by a filter and a current third output voltage of the DC / AC converter after being filtered by the filter, and drive the DC / AC converter according to the second duty cycle control quantity to adjust a frequency of electric energy output to a power grid by the DC / AC converter. The first duty cycle control quantity is determined based on the current frequency, the additional adjustment term of the sliding surface, a current first output voltage and a current first output current of a photovoltaic array in the photovoltaic power generation system, and includes: The current frequency, the current first output voltage and the current first output current are brought into a frequency adjustment parameter determination formula to determine a current frequency adjustment parameter; A current sliding surface control parameter is determined according to the current frequency adjustment parameter, the additional adjustment term of the sliding surface and a sliding surface control parameter determination formula; The first duty cycle control quantity is determined based on the sliding surface control parameter and the current first output voltage; The frequency adjustment parameter determination formula is: ; for the current frequency adjustment parameter, , , the current frequency, the current first output voltage, and the current first output current, respectively. The sliding mode surface control parameter determination formula is: ; wherein, is the current sliding mode surface control parameter, and are a first and second weight factor, respectively, is the sliding mode surface additional adjustment term; The first duty cycle control quantity is determined based on the sliding surface control parameter and the current first output voltage, and includes: The sliding surface control parameter is brought into a photovoltaic voltage reference value confirmation formula to determine a current photovoltaic voltage reference value; The first duty cycle control quantity is determined according to the current photovoltaic voltage reference value, the current first output voltage and a duty cycle control quantity confirmation formula; The photovoltaic voltage reference value confirmation formula is: ; is the current photovoltaic voltage reference value, , and are a third, fourth and fifth weight factor, respectively, is a sign function; The duty cycle control amount confirmation formula is: ; wherein, is the first duty cycle control amount, , are a preset proportional coefficient and an integral coefficient of PI control, respectively.

7. An electronic device, comprising: The computer readable storage medium stores a computer program, and the computer program is executed by the processor to realize the steps of the power grid frequency regulation control method according to any one of claims 1 to 5. The computer readable storage medium stores a computer program, and the computer program is executed by the processor to realize the steps of the power grid frequency regulation control method according to any one of claims 1 to 5. ​ 8. A computer-readable storage medium, characterized in that, ​

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