A frequency modulation control parameter setting method and system of a photovoltaic power generation grid-connected system

Abstract

The application discloses a frequency modulation control parameter setting method and system of a photovoltaic power generation grid-connected system, and comprises the following steps: acquiring the maximum frequency variation rate and the maximum steady-state frequency deviation of power distribution network operation of the photovoltaic power generation grid-connected system; based on the maximum frequency variation rate and the maximum steady-state frequency deviation, determining a first value range of a first coefficient of a frequency variation rate control branch and a second value range of a second coefficient of a frequency deviation control branch which simultaneously satisfy the constraints of power grid frequency guide and the stable operation constraints of the equipment itself; and based on the first value range and the second value range, setting the first coefficient and the second coefficient. The application considers the system frequency support provided by the equipment itself, adds the constraint requirements of the power grid constraint condition and the equipment itself standby margin, sets the frequency modulation control parameters of the photovoltaic power generation grid-connected system, can enhance the stability of the power system, has simple structure, simple calculation and universality.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of grid-connected frequency support of photovoltaic power generation grid-connected systems, and more particularly to a frequency control parameter setting method and system for photovoltaic power generation grid-connected systems. BACKGROUND

[0002] As a renewable energy source, photovoltaic power generation has become one of the most mature and widely used technologies for solar energy utilization. With the continuous expansion of photovoltaic power generation application scale, the sustained progress of technology, and the accelerated decline of cost in China, photovoltaic power generation has become the main force of new power supply investment.

[0003] Power electronics equipment is widely used in photoelectric, direct current transmission and reactive power compensation systems. The damping and inertia of high-proportion new energy power systems have changed greatly, and the impact on the power grid is increasingly significant. When photovoltaic power generation replaces synchronous machines in large quantities, the power electronics characteristics of the power system are highlighted, and the rotational reserve capacity and rotational inertia of the power system are relatively reduced, which will lead to a decrease in the inertia level of the system, deterioration of the frequency response characteristics, weakening of the ability of the system to resist power differences, and an increase in the pressure on the safe and stable operation of the power system.

[0004] To provide frequency support to the alternating current system, in addition to directly starting from the perspective of power flow control, more is to use frequency droop control, or to increase the equivalent inertia and damping of the alternating current system. Existing literature reports the use of direct current side capacitor energy storage to simulate the inertia of the alternating current side, and further provides inertia and damping for the bilateral alternating current system. However, due to the range of direct current side voltage change and the size of the capacitor, the support of the capacitor to the alternating current side frequency is limited. The virtual synchronous machine technology is an effective means to improve the inertia and damping of the system, but this technology is less used in the power coordination control of VSC-BTB systems. Based on this, related research has also proposed an alternating current frequency support method while retaining the phase locked loop (PLL).

[0005] The existing active-frequency control strategy of new energy power generation grid-connected is summarized, which can be divided into three categories from the basic working principle: phase-locked regulation, power instruction regulation, and virtual synchronous mode. The phase-locked loop regulation technology has defects, changing the phase-locked structure can easily cause small signal stability problems, and changing the phase-locked parameter can easily reduce the grid tracking ability of the converter, and there is no actual application. The virtual synchronous control and power instruction regulation are two mature frequency active support methods, but the virtual synchronous control has a large change in the control structure, and the application occasion is limited, which is not suitable for occasions that bear direct current voltage control. At the same time, the existing design research mainly provides frequency support on the device itself, and does not consider the frequency constraint conditions of the power grid.

[0006] Therefore, there is a need for a frequency control parameter setting method for a photovoltaic power generation grid-connected system based on device self-constraints and power grid frequency constraints. SUMMARY

[0007] The present application provides a frequency control parameter setting method and system for a photovoltaic power generation grid-connected system to solve the problem of how to quickly set the frequency control parameters of the photovoltaic power generation grid-connected system.

[0008] To solve the above problems, according to one aspect of the present application, a frequency control parameter setting method for a photovoltaic power generation grid-connected system is provided, the method comprising:

[0009] obtaining a maximum frequency change rate and a maximum steady-state frequency deviation of a power distribution network operation of the photovoltaic power generation grid-connected system;

[0010] based on the maximum frequency change rate and the maximum steady-state frequency deviation, determining a first value range of a first coefficient of a frequency change rate control branch and a second value range of a second coefficient of a frequency deviation control branch that simultaneously satisfy the power grid frequency guide constraint and the device self-stable operation constraint;

[0011] setting the first coefficient and the second coefficient based on the first value range and the second value range.

[0012] Preferably, wherein the photovoltaic power generation grid-connected system comprises: photovoltaic panels, DC / DC direct current converters, DC / AC alternating current inverters and power grids connected in sequence, the DC / DC direct current converters are used to boost the voltage, the DC / AC alternating current inverters are used to connect to the power grid, the DC / AC alternating current inverters are controlled by a constant direct current voltage, the DC / DC direct current converters of the photovoltaic power generation grid-connected system are controlled by a constant power, and the constant power control is introduced with two feedback branches of frequency deviation and frequency change rate.

[0013] Preferably, wherein the first value range is determined by the following method, comprising:

[0014] ,

[0015] wherein, is the first coefficient; is the maximum disturbance power that the power distribution network system may occur; is the rated power of the synchronous machine; H is the inertia time constant; is the maximum frequency change rate allowed by the power distribution network; is the rated frequency of the steady-state operation of the system; is the short-time overload capacity of the device; is the maximum power of the photovoltaic power generation grid-connected system.

[0016] Preferably, the second value range is determined by the following method, comprising:

[0017] ,

[0018] ,

[0019] wherein, is the second coefficient; is the maximum disturbance power that the power distribution network system can occur; is the rated power of the synchronous machine; is the maximum allowable steady-state frequency deviation; is the value of the reheater type steam turbine generator governor when s=0; is the proportion of the standby capacity; is the high-pressure cylinder power coefficient of the reheater type steam turbine generator governor system; is the rotor action time constant of the reheater type steam turbine generator governor system; is the high-pressure steam volume time of the reheater type steam turbine generator governor system; is the reheated steam volume time of the reheater type steam turbine generator governor system.

[0020] According to another aspect of the present application, a frequency modulation control parameter setting system of a photovoltaic power generation grid-connected system is provided, the system comprising:

[0021] a data acquisition unit configured to acquire the maximum frequency change rate and the maximum steady-state frequency deviation of the power distribution network operation of the photovoltaic power generation grid-connected system;

[0022] a coefficient value range determination unit configured to determine, based on the maximum frequency change rate and the maximum steady-state frequency deviation, a first value range of a first coefficient of a frequency change rate control branch and a second value range of a second coefficient of a frequency deviation control branch that simultaneously satisfy the grid frequency guide constraint and the device itself stable operation constraint;

[0023] a setting unit configured to set the first coefficient and the second coefficient based on the first value range and the second value range.

[0024] Preferably, the photovoltaic power generation grid-connected system comprises: photovoltaic panels, DC / DC direct current converters, DC / AC direct current inverters and a power grid connected in sequence, the DC / DC direct current converters are used to boost the voltage, the direct current voltage is controlled by a capacitor, and the DC / AC direct current inverters are used to connect to the power grid; the DC / AC direct current inverters adopt constant direct current voltage control, the DC / DC direct current converters of the photovoltaic power generation grid-connected system adopt constant power control, and the constant power control is introduced with two feedback branches of frequency deviation and frequency change rate.

[0025] Preferably, the first value range is determined by the following method, comprising:

[0026] ,

[0027] wherein, is a first coefficient; is a maximum disturbance power that may occur in the power distribution network system; is a rated power of the synchronous machine; H is an inertia time constant; is a maximum frequency change rate allowed by the power distribution network; is a rated frequency of steady-state operation of the system; is a short-time overload capacity of the device; is a maximum power of the photovoltaic power generation grid-connected system.

[0028] Preferably, the second value range is determined by the following method, comprising:

[0029] ,

[0030] ,

[0031] wherein, is a second coefficient; is a maximum disturbance power that may occur in the power distribution network system; is a rated power of the synchronous machine; is a maximum steady-state frequency deviation allowed; is a value of the reheater-type steam turbine generator governor at s=0; is a proportion of the backup capacity; is a high-pressure cylinder power coefficient of the reheater-type steam turbine generator governor system; is a rotor action time constant of the reheater-type steam turbine generator governor system; is a high-pressure steam volume time of the reheater-type steam turbine generator governor system; is a reheated steam volume time of the reheater-type steam turbine generator governor system.

[0032] Based on another aspect of the present application, the present application provides a computer readable storage medium having stored thereon a computer program, which, when executed by a processor, implements the steps of any one of the frequency control parameter setting methods for a photovoltaic power generation grid-connected system.

[0033] Based on another aspect of the present application, the present application provides an electronic device, comprising:

[0034] the computer readable storage medium described above; and

[0035] One or more processors to execute the program in the computer readable storage medium.

[0036] The application provides a frequency control parameter setting method and system for a photovoltaic power generation grid-connected system, comprising: obtaining a maximum frequency variation rate and a maximum steady-state frequency deviation of power distribution network operation of the photovoltaic power generation grid-connected system; determining a first value range of a first coefficient of a frequency variation rate control branch and a second value range of a second coefficient of a frequency deviation control branch which simultaneously satisfy a power grid frequency guide constraint and a device self-stable operation constraint based on the maximum frequency variation rate and the maximum steady-state frequency deviation; and setting the first coefficient and the second coefficient based on the first value range and the second value range. The application considers the equipment self-provided system frequency support, adds the constraint requirements of the power grid constraint condition and the device self-reserve margin, sets the frequency control parameters of the photovoltaic power generation grid-connected system, can enhance the power system stability, has simple structure, simple calculation and universality. BRIEF DESCRIPTION OF DRAWINGS

[0037] The exemplary embodiments of the present application can be more fully understood with reference to the accompanying drawings, in which:

[0038] Figure 1 A flow chart of the frequency control parameter setting method 100 for the photovoltaic power generation grid-connected system according to the embodiments of the application;

[0039] Figure 2 A control block diagram of the photovoltaic power generation grid-connected system according to the embodiments of the application;

[0040] Figure 3 A power distribution network frequency response analysis block diagram according to the embodiments of the application;

[0041] Figure 4 (a) and (b) are respectively the df / df frequency variation rate response result and the Δf frequency variation response result under frequency according to the embodiments of the application;

[0042] Figure 5 A structural schematic diagram of the frequency control parameter setting system 500 for the photovoltaic power generation grid-connected system according to the embodiments of the application. DETAILED DESCRIPTION

[0043] The exemplary embodiments of the present application will now be described with reference to the accompanying drawings. The present application can, however, be carried out in many different ways, and is not limited to the embodiments described herein. These embodiments are provided so that this disclosure will be thorough and complete, and fully convey the scope of the application to those skilled in the art. The terminology used in the description of the exemplary embodiments herein is not intended to be limiting of the present application. Identical elements are denoted using identical reference numerals in the various embodiments.

[0044] Unless otherwise stated, the terms used herein (including technical terms) have their common meaning as understood by one of ordinary skill in the art. Furthermore, it is understood that terms defined in commonly used dictionaries should be understood to have a meaning consistent with the context of their relevant field, and not to be interpreted as having an idealized or overly formal meaning.

[0045] Figure 1 This is a flowchart of a frequency regulation control parameter tuning method 100 for a photovoltaic power generation grid-connected system according to an embodiment of the present invention. Figure 1 As shown, the frequency regulation control parameter tuning method for a photovoltaic power generation grid-connected system provided by this invention, while considering the system frequency support provided by the equipment itself, incorporates grid constraints and the equipment's own reserve margin requirements to tune the frequency regulation control parameters of the photovoltaic power generation grid-connected system. This enhances power system stability, has a simple structure, is easy to calculate, and is universally applicable. The frequency regulation control parameter tuning method 100 for a photovoltaic power generation grid-connected system provided by this invention begins at step 101. In step 101, the maximum frequency change rate and the maximum steady-state frequency deviation of the distribution network operation of the photovoltaic power generation grid-connected system are obtained.

[0046] Preferably, the photovoltaic power generation grid-connected system includes: a photovoltaic panel, a DC / DC converter, a DC / AC inverter, and a power grid connected in sequence. The DC voltage is boosted by the DC / DC converter, controlled by a capacitor, and then connected to the grid through the DC / AC inverter. The DC / AC inverter adopts constant DC voltage control, and the DC / DC converter of the photovoltaic power generation grid-connected system adopts constant power control. Two feedback branches, frequency deviation and frequency change rate, are introduced into the constant power control.

[0047] In step 102, based on the maximum frequency change rate and the maximum steady-state frequency deviation, the first value range of the first coefficient of the frequency change rate control branch and the second value range of the second coefficient of the frequency deviation control branch are determined, which simultaneously satisfy the constraints of the power grid frequency guidelines and the equipment's own stable operation.

[0048] Preferably, the first value range is determined using the following methods:

[0049] ,

[0050] in, The first coefficient; This represents the maximum disturbance power that may occur in the power distribution network system. This refers to the rated power of the synchronous machine; H The inertial time constant; This represents the maximum permissible rate of frequency change in the distribution network. The rated frequency for steady-state operation of the system; This refers to the short-term overload capacity of the equipment. This represents the maximum power output of the grid-connected photovoltaic power generation system.

[0051] Preferably, the second value range is determined using the following methods:

[0052] ,

[0053] ,

[0054] in, The second coefficient; This represents the maximum disturbance power that may occur in the power distribution network system. This refers to the rated power of the synchronous machine; The maximum allowable steady-state frequency deviation; This is the value of the governor of the reheater-type steam turbine generator when s=0; This represents the percentage of standby capacity. The power coefficient of the high-pressure cylinder in the governor system of a reheater-type steam turbine generator. The rotor operating time constant of the reheater-type steam turbine generator governor system; For the high-pressure steam volume time of the reheater-type steam turbine generator governor system; The reheat steam volume time is the time required for the governor system of a reheater-type steam turbine generator.

[0055] like Figure 2 As shown, in this invention, the photovoltaic power generation grid-connected system boosts the DC voltage through a DC / DC converter, controls the DC voltage using a capacitor, and then connects to the grid through an AC / DC inverter. The DC / AC converter in the photovoltaic power generation system employs constant DC voltage control, while the DC / DC converter in the photovoltaic power generation system employs constant power control. Two feedback branches, frequency deviation (Δf) and frequency change rate RoCoF, are introduced into the constant power control. Based on existing frequency regulation strategies for active power command regulation, the photovoltaic power generation system adds a branch with frequency information to the power command to control the DC / DC converter, thereby achieving frequency support for the photovoltaic power generation system.

[0056] Combination Figure 3 As shown, when a photovoltaic power generation system is disturbed, resulting in unbalanced power, the expressions for the steady-state frequency deviation and frequency change rate of the power system in the frequency domain are:

[0057]

[0058] Among them, the DC / DC converter of the photovoltaic power generation system adopts constant power control and frequency regulation through power command adjustment. RoCoF represents the rate of change of frequency. Indicates frequency deviation; The coefficient of the control branch is the frequency change rate RoCoF; The coefficient of the control branch for frequency deviation; The rated frequency for steady-state operation of the system; The inertial time constant of the synchronous machine, The transfer function for the governor of the reheater-type steam turbine generator is expressed as follows:

[0059]

[0060] In the formula, The power coefficient of the high-pressure cylinder in the reheater-type steam turbine generator governor system. The rotor operating time constant of the reheater-type steam turbine generator governor system. The high-pressure steam volume time is the time required for the governor system of a reheater-type steam turbine generator. The reheat steam volume time is the time required for the governor system of a reheater-type steam turbine generator.

[0061] In this invention, in addition to considering the system frequency support provided by the equipment itself, constraints on the power grid and the equipment's own reserve capacity are added.

[0062] 1) Power Grid Frequency Guidelines Constraints

[0063] The parameter tuning for grid-connected photovoltaic (PV) power generation systems to provide frequency support requires adherence to the grid frequency guidelines. By consulting the grid frequency guidelines, the allowable ranges for system frequency deviation and rate of change are determined. The minimum values ​​of the parameters for the two control feedback branches of the PV power generation system are then calculated using the following formulas.

[0064] The initial value theorem is used to calculate the rate of change of frequency at the initial moment:

[0065]

[0066] Using the final value theorem, calculate the steady-state deviation of the frequency:

[0067]

[0068] In the formula: This represents the maximum disturbance power that may occur in the power distribution network system. This refers to the rated power of the synchronous machine; H The inertial time constant; This is the value of the governor of the reheater-type steam turbine generator when s=0; The maximum allowable rate of frequency change in the distribution network. This represents the maximum permissible steady-state frequency deviation.

[0069] 2) Constraints on the stable operation of the equipment itself

[0070] In this invention, by querying the stable operating conditions of the equipment, the range of values ​​for the backup capacity that the equipment itself can use to provide frequency support is confirmed, and constraints that need to be met to satisfy the system's own backup capacity and the equipment's overload capacity are set.

[0071] During frequency disturbance events, the active power supplied by equipment to the distribution network cannot exceed the reserved reserve capacity (used for...). η Under frequency disturbance events, the active power provided by the equipment to the distribution network cannot exceed the reserved reserve capacity (denoted by η, representing the percentage of reserve capacity). Therefore, there is a constraint:

[0072]

[0073] In the formula: This refers to the rated power of the photovoltaic system.

[0074] Under frequency disturbance events, the active power support provided by the equipment to the distribution network is in a short-term overload state (denoted by ζ, representing the equipment's short-term overload capacity). The active power support provided by the equipment cannot exceed its short-term overload limit, and there are constraints:

[0075]

[0076] From equations (4), (5), (6), and (7), we can derive the formulas for calculating the first range of values ​​for the first coefficient of the frequency change rate control branch and the second range of values ​​for the second coefficient of the frequency deviation control branch, which simultaneously satisfy the constraints of the power grid frequency guidelines and the equipment's own stable operation.

[0077]

[0078] in, The first coefficient; This represents the maximum disturbance power that may occur in the power distribution network system. This refers to the rated power of the synchronous machine; H The inertial time constant; This represents the maximum permissible rate of frequency change in the distribution network. The rated frequency for steady-state operation of the system; This refers to the short-term overload capacity of the equipment. This represents the maximum power output of the grid-connected photovoltaic power generation system. The second coefficient; The maximum allowable steady-state frequency deviation; This is the value of the governor of the reheater-type steam turbine generator when s=0.

[0079] Therefore, in this invention, after determining the system operating data, the system can be determined based on formulas (8) and (9). K 1 and K 2.

[0080] In step 103, the first coefficient and the second coefficient are adjusted based on the first value range and the second value range.

[0081] In this invention, values ​​are randomly selected from a defined range to adjust the first and second coefficients. The selected first and second coefficients can simultaneously ensure stable system operation and meet the operational requirements of the equipment itself.

[0082] This invention proposes a frequency regulation control parameter tuning method based on a photovoltaic power generation system that operates on the principle of regulating control power commands. This method enables the tuning of frequency regulation control parameters under system and equipment constraints. Based on active power control commands, and constrained by grid frequency guidelines and equipment stable operation, a method for tuning frequency regulation control parameters of a photovoltaic power generation system is obtained. The method is simple, easy to calculate, and has universal applicability.

[0083] The following is Figure 2 Taking the frequency regulation strategy based on active power command regulation in the photovoltaic power generation grid-connected system as an example, constant power control is adopted for the DC / DC converter of the photovoltaic power generation system, and two feedback branches, frequency deviation and frequency change rate RoCoF, are introduced to illustrate the effect of the method of the present invention.

[0084] Table 1 shows the Simulink simulation parameters for MATLAB. The rated frequency for steady-state operation of the system; The inertial time constant of the synchronous machine; This represents the maximum disturbance power that may occur in the power distribution network system. This represents the maximum power output of the photovoltaic power generation system. This refers to the rated power of the synchronous machine; The maximum allowable rate of frequency change in the distribution network. The maximum allowable steady-state frequency deviation; For the speed regulation branch transfer function, This is the value of s=0 for the synchronous speed controller.

[0085] From equations (8) and (9), the range of values ​​for the control parameters can be obtained as follows: and .

[0086] Through simulation analysis, the frequency response effect is obtained as follows: Figure 4 As shown. Among them, Figure 4 In the middle (a), the frequency change rate response results are shown under df / df.K When 1 = 0.05, the value is outside the range, and the rate of change of frequency exceeds the maximum value. K When 1=0.1, within the range of values, the obtained frequency change rate is also within the maximum value, and the simulation results are consistent with the theoretical control parameter tuning process; Figure 4 (b) in the middle is Frequency change response results, when K When 2 = 0.1, outside the range of values, the rate of change of frequency exceeds the maximum value. K When 2=0.2, within the range of values, the obtained frequency change rate is also within the maximum value, and the simulation results are consistent with the theoretical control parameter tuning process. Therefore, the simulation results show that the present invention can simply and effectively design the frequency regulation control parameters of a photovoltaic power generation system.

[0087] Table 1 Simulation Parameter Design

[0088]

[0089] Figure 5 This is a schematic diagram of the frequency regulation control parameter tuning system 500 of a photovoltaic power generation grid-connected system according to an embodiment of the present invention. Figure 5 As shown, the frequency regulation control parameter setting system 500 of the photovoltaic power generation grid-connected system provided in this embodiment of the invention includes: a data acquisition unit 501, a coefficient value range determination unit 502, and a setting unit 503.

[0090] Preferably, the data acquisition unit 501 is used to acquire the maximum frequency change rate and the maximum steady-state frequency deviation of the distribution network operation of the photovoltaic power generation grid-connected system.

[0091] Preferably, the photovoltaic power generation grid-connected system includes: a photovoltaic panel, a DC / DC converter, a DC / AC inverter, and a power grid connected in sequence. The DC voltage is boosted by the DC / DC converter, controlled by a capacitor, and then connected to the grid through the DC / AC inverter. The DC / AC inverter adopts constant DC voltage control, and the DC / DC converter of the photovoltaic power generation grid-connected system adopts constant power control. Two feedback branches, frequency deviation and frequency change rate, are introduced into the constant power control.

[0092] Preferably, the first value range is determined using the following methods:

[0093] ,

[0094] in, The first coefficient; This represents the maximum disturbance power that may occur in the power distribution network system. This refers to the rated power of the synchronous machine; HThe inertial time constant; This represents the maximum permissible rate of frequency change in the distribution network. The rated frequency for steady-state operation of the system; This refers to the short-term overload capacity of the equipment. This represents the maximum power output of the grid-connected photovoltaic power generation system.

[0095] Preferably, the coefficient value range determination unit 502 is used to determine, based on the maximum frequency change rate and the maximum steady-state frequency deviation, the first value range of the first coefficient of the frequency change rate control branch and the second value range of the second coefficient of the frequency deviation control branch, which simultaneously satisfy the constraints of the power grid frequency guidelines and the equipment's own stable operation.

[0096] Preferably, the second value range is determined using the following methods:

[0097] ,

[0098] ,

[0099] in, The second coefficient; This represents the maximum disturbance power that may occur in the power distribution network system. This refers to the rated power of the synchronous machine; The maximum allowable steady-state frequency deviation; This is the value of the governor of the reheater-type steam turbine generator when s=0; This represents the percentage of standby capacity. The power coefficient of the high-pressure cylinder in the governor system of a reheater-type steam turbine generator. The rotor operating time constant of the reheater-type steam turbine generator governor system; For the high-pressure steam volume time of the reheater-type steam turbine generator governor system; The reheat steam volume time is the time required for the governor system of a reheater-type steam turbine generator.

[0100] Preferably, the tuning unit 503 is used to tune the first coefficient and the second coefficient based on the first value range and the second value range.

[0101] The frequency regulation control parameter tuning system 500 of the photovoltaic power generation grid-connected system in this embodiment corresponds to the frequency regulation control parameter tuning method 100 of the photovoltaic power generation grid-connected system in another embodiment of this invention, and will not be described again here.

[0102] According to another aspect of the present invention, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements any of the steps in a method for setting frequency regulation control parameters of a photovoltaic power generation grid-connected system.

[0103] According to another aspect of the present invention, the present invention provides an electronic device, comprising:

[0104] The aforementioned computer-readable storage medium; and

[0105] One or more processors for executing a program in the computer-readable storage medium.

[0106] The invention has been described with reference to a few embodiments. However, as will be known to those skilled in the art, and as defined in the appended claims, other embodiments besides those disclosed above fall equivalently within the scope of the invention.

[0107] Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the art, unless otherwise expressly defined herein. All references to “a / the / the [device, component, etc.]” ​​are openly interpreted as at least one instance of said device, component, etc., unless otherwise expressly stated. The steps of any method disclosed herein need not be performed in the exact order disclosed unless explicitly stated otherwise.

[0108] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0109] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0110] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0111] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0112] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for tuning frequency regulation control parameters in a photovoltaic power generation grid-connected system, characterized in that, The method includes: Obtain the maximum rate of frequency change and the maximum steady-state frequency deviation of the photovoltaic power generation grid-connected system's distribution network operation; Based on the maximum frequency change rate and the maximum steady-state frequency deviation, determine the first value range of the first coefficient of the frequency change rate control branch and the second value range of the second coefficient of the frequency deviation control branch, which simultaneously satisfy the constraints of the power grid frequency guidelines and the equipment's own stable operation. The first coefficient and the second coefficient are adjusted based on the first value range and the second value range; The first value range is determined using the following methods: ， in, The first coefficient; This represents the maximum disturbance power that may occur in the power distribution network system. This refers to the rated power of the synchronous machine; H The inertial time constant; This represents the maximum permissible rate of frequency change in the distribution network. The rated frequency for steady-state operation of the system; This refers to the short-term overload capacity of the equipment. This represents the maximum power output of the grid-connected photovoltaic power generation system. The second value range is determined using the following methods: ， ， in, The second coefficient; The maximum allowable steady-state frequency deviation; This is the value of the governor of the reheater-type steam turbine generator when s=0; This represents the percentage of standby capacity. The power coefficient of the high-pressure cylinder in the governor system of a reheater-type steam turbine generator. The rotor operating time constant of the reheater-type steam turbine generator governor system; For the high-pressure steam volume time of the reheater-type steam turbine generator governor system; The reheat steam volume time is the time required for the governor system of a reheater-type steam turbine generator.

2. The method according to claim 1, characterized in that, The photovoltaic power generation grid-connected system includes: photovoltaic panels, a DC / DC converter, a DC / AC inverter, and the power grid connected in sequence. The DC voltage is boosted by the DC / DC converter, controlled by a capacitor, and then connected to the grid through the DC / AC inverter. The DC / AC inverter adopts constant DC voltage control, and the DC / DC converter of the photovoltaic power generation grid-connected system adopts constant power control. Two feedback branches, frequency deviation and frequency change rate, are introduced into the constant power control.

3. A frequency regulation control parameter tuning system for a photovoltaic power generation grid-connected system, characterized in that, The system includes: The data acquisition unit is used to acquire the maximum frequency change rate and the maximum steady-state frequency deviation of the distribution network operation of the photovoltaic power generation grid-connected system; The coefficient value range determination unit is used to determine, based on the maximum frequency change rate and the maximum steady-state frequency deviation, the first value range of the first coefficient of the frequency change rate control branch and the second value range of the second coefficient of the frequency deviation control branch, which simultaneously satisfy the grid frequency guideline constraints and the equipment's own stable operation constraints. The tuning unit is used to tune the first coefficient and the second coefficient based on the first value range and the second value range; The first value range is determined using the following methods: ， in, The first coefficient; This represents the maximum disturbance power that may occur in the power distribution network system. This refers to the rated power of the synchronous machine; H The inertial time constant; This represents the maximum permissible rate of frequency change in the distribution network. The rated frequency for steady-state operation of the system; This refers to the short-term overload capacity of the equipment. This represents the maximum power output of the grid-connected photovoltaic power generation system. The second value range is determined using the following methods: ， ， in, The second coefficient; The maximum allowable steady-state frequency deviation; This is the value of the governor of the reheater-type steam turbine generator when s=0; This represents the percentage of standby capacity. The power coefficient of the high-pressure cylinder in the governor system of a reheater-type steam turbine generator. The rotor operating time constant of the reheater-type steam turbine generator governor system; For the high-pressure steam volume time of the reheater-type steam turbine generator governor system; The reheat steam volume time is the time required for the governor system of a reheater-type steam turbine generator.

4. The system according to claim 3, characterized in that, The photovoltaic power generation grid-connected system includes: photovoltaic panels, a DC / DC converter, a DC / AC inverter, and the power grid connected in sequence. The DC voltage is boosted by the DC / DC converter, controlled by a capacitor, and then connected to the grid through the DC / AC inverter. The DC / AC inverter adopts constant DC voltage control, and the DC / DC converter of the photovoltaic power generation grid-connected system adopts constant power control. Two feedback branches, frequency deviation and frequency change rate, are introduced into the constant power control.

5. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the steps of the method as described in any one of claims 1-2.

6. An electronic device, characterized in that, include: The computer-readable storage medium as described in claim 5; as well as One or more processors for executing a program in the computer-readable storage medium.

Images