A method and system for coordinated power control of multiple types of equipment suitable for microgrids

Abstract

The present invention discloses a method and system for coordinated power control of multiple types of equipment suitable for microgrids. The method mainly solves the problem that in complex new energy microgrids, various power generation and energy storage equipment have large differences in response characteristics and response times, and it is not appropriate to use a single control algorithm. The present invention uniformly models various types of equipment, so that the control objects in the microgrid are simplified to equipment with consistent models and different parameters. A single control task is decomposed according to the control time and power change rate of each device, and one control is decomposed into two sub-control steps. The first control goal is to make full use of all equipment to reach the target power of the entire station as soon as possible, and the second control goal is to smoothly adjust all equipment to achieve the expected power of each device. Through the above method, the adjustment capacity of all equipment in the station can be fully utilized, and at the same time, the system can take into account power generation and consumption plans such as peak shaving and valley filling as much as possible.

Description

Technical Field

[0001] The present invention relates to a method and system for coordinated power control of multiple types of equipment applicable to a microgrid, and belongs to the technical field of power grid control. Background Art

[0002] Under the new situation, renewable energy power generation has been more widely used, and the number of microgrids is also increasing. For renewable energy microgrids that need to be connected to the large power grid, an energy management system is generally required to manage the energy of the entire renewable energy microgrid, especially the need to accurately control the active power, reactive power, voltage, frequency, etc. of the microgrid connection point. The part involving active power control generally includes automatic generation control system (AGC), primary frequency control system (PFC) and battery management system (BMS).

[0003] For a single type of microgrid, such as a wind farm or photovoltaic power station, the control system is often relatively simple, and a set of PID control algorithms can be used to control the active power output of the entire power station. For a complex new energy microgrid, it may include photovoltaic equipment, wind turbine equipment, energy storage equipment, and traditional diesel generators. When a microgrid contains multiple devices at the same time, it is difficult to take into account the different response characteristics of various types of equipment using a single control algorithm.

[0004] Taking wind turbines and photovoltaic equipment as examples, the adjustment speed of wind turbines is generally slow, requiring 5-10 seconds. Some photovoltaic equipment with better performance only requires 1-5 seconds to complete the adjustment work. Energy storage equipment can often be adjusted to the set value within 1 second. The commonly used control algorithm is PID control, and it is often difficult to adjust them at the same time using the same set of control parameters.

[0005] For AGC and PFC systems, the commonly used control scheme is to select one of the devices for regulation, or to prioritize several devices for regulation. For microgrids with wind power + energy storage, frequency regulation can be performed once with wind power only, once with energy storage, or once with a combination of wind turbines and energy storage. The combination of wind turbines and energy storage generally gives priority to one of them, and when the regulation resources of one are exhausted, the other is used. The regulation effect of this method is general, and the utilization rate of the regulation performance of the microgrid is not high. With the development of microgrids, the number of microgrids in various regions continues to increase, and the structure becomes more complex. A more general and efficient control algorithm is urgently needed. Summary of the invention

[0006] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a method and system for coordinated power control of multiple types of equipment suitable for microgrids, which can improve the control accuracy, rapidity and stability of automatic power generation control systems and primary frequency regulation systems.

[0007] To achieve the above object, the present invention is implemented by adopting the following technical solutions:

[0008] In a first aspect, the present invention provides a method for coordinated power control of multiple types of devices applicable to a microgrid, comprising the following steps:

[0009] For all power generation and energy storage equipment in the new energy microgrid, a unified model is used to describe multiple parameters; and various parameters of the unified model are obtained in real time;

[0010] Update the total power target value of the system in real time;

[0011] When the total system power target value changes, the output power of all devices is adjusted to the new total target power value of the entire site.

[0012] Furthermore, the unified model includes the following parameters:

[0013] Rated power, real-time power, adjustable upper and lower limits of power, maximum power change rate, and expected power.

[0014] Furthermore, the method for obtaining various parameters of the unified model in real time includes the following steps:

[0015] Get the rated power;

[0016] Get real-time power;

[0017] Get the adjustable upper and lower limits of power;

[0018] Get the maximum power change rate;

[0019] Get the expected power.

[0020] Further, methods for obtaining the rated power include obtaining it through the equipment manufacturer's manual;

[0021] Methods for obtaining real-time power include reading through protocol;

[0022] Methods for obtaining the upper and lower limits of adjustable power include:

[0023] If the device is a power generation device, the upper and lower limits of the adjustable power are the maximum or minimum output power that the current device can achieve based on the current wind and solar resources. If the device is an energy storage device, the upper and lower limits of the adjustable power are the maximum power allowed for charging and discharging of the current energy storage device.

[0024] The maximum power change rate is the maximum change speed of the real-time power of the device in unit time under the current working condition.

[0025] Furthermore, the method for obtaining the expected power includes:

[0026] Calculate the power difference between the total power target value and the peak-shaving and valley-filling planned power of the BMS system. If the power difference is within the total adjustable upper and lower limits of the wind and solar equipment, the peak-shaving and valley-filling requirements of the energy storage equipment and the total power target are met at the same time.

[0027] At this time, the expected power of the energy storage device is the planned power for peak shaving and valley filling, and the expected power of the wind and solar devices is the remaining power evenly distributed according to the upper and lower limits of the wind and solar adjustable limits;

[0028] If the power difference exceeds the upper and lower limits of wind and solar equipment, the power generation capacity of wind and solar equipment will be fully utilized to give priority to meeting the total power target, and secondly, the peak shaving and valley filling needs of energy storage equipment will be met as much as possible; at this time, the expected power of wind and solar equipment is the adjustable upper and lower limits, and the expected power of the energy storage equipment is the remaining power, which is evenly distributed according to the adjustable upper and lower limits of the energy storage equipment.

[0029] Furthermore, the method for updating the total power target value of the system in real time includes:

[0030] When the dispatching AGC instruction is received, or the FPC system receives the frequency change of the grid connection point, or the BMS system modifies the system's energy storage charging and discharging target value according to the energy storage management plan, the system's total power target value changes, and the new system total power target value is recalculated.

[0031] Furthermore, the method for adjusting the output power of all devices to a new total target power value of the entire station includes:

[0032] The power of wind, solar and storage equipment is allocated based on the total power target value and the calculated power difference to be allocated detected at the grid connection point;

[0033] Adjust from current power to expected power, keeping the total power of the entire station unchanged during the adjustment process.

[0034] Furthermore, the method for distributing the power of the wind-solar-storage device based on the total power target value and the power difference to be distributed detected at the grid connection point includes the following steps:

[0035] Step A: Obtaining the unallocated power difference;

[0036] Step B: Determine whether there is an unallocated power difference, if so, jump to step C; otherwise jump to step E;

[0037] Step C: Allocate all unallocated power differences to devices whose allocated power does not reach the upper and lower power limits, and the allocation weight is the maximum power change rate of the device;

[0038] Step D: Determine whether the power allocation of all devices has reached the upper and lower limits. If yes, jump to step E; otherwise, jump to step A.

[0039] Step E: Send power according to the allocated value to control the output power of the device;

[0040] Step F: Determine whether the actual power of the entire station reaches the total power target value. If yes, maintain the current power; otherwise, jump to step A.

[0041] Furthermore, the method of adjusting from the current power to the expected power and keeping the total power of the entire station unchanged during the adjustment process includes:

[0042] Calculate the adjustment time of this step, calculate the expected active power difference of all devices, and divide it by the power change rate of the device to obtain the power change time;

[0043] Select the maximum power change time among all devices as the adjustment time of the second stage;

[0044] Control all devices to calculate the required power change rate according to the adjustment time. The power change rate is equal to the difference between the expected active power of each device and the adjustment time;

[0045] All devices adjust the power in steps according to the power change rate until all devices reach the expected power value.

[0046] Furthermore, the method for calculating the adjustment time of this step is: calculate the time required for all devices to adjust from the current power to the expected power according to the maximum power change rate, and select the maximum value of the adjustment time required for each device as the adjustment time for this stage.

[0047] In a second aspect, the present invention provides a multi-type device power coordination control system applicable to a microgrid, comprising:

[0048] Parameter acquisition module: used to describe all power generation and energy storage equipment in the new energy microgrid as multiple parameters using a unified model; and to obtain various parameters of the unified model in real time;

[0049] Total power target calculation module: used to update the total power target value of the system in real time;

[0050] Wind, solar and storage power allocation module: used to adjust the output power of all devices to the new total target power value of the entire station when the total power target value of the system changes.

[0051] Compared with the prior art, the present invention has the following beneficial effects:

[0052] 1. The present invention uses a unified model to manage various devices in a unified manner, improves the compatibility of the system, and reduces the complexity of program implementation and engineering application. In the new energy microgrid, when there are multiple devices with different response characteristics, a unified control model is used for various types of devices, and a control algorithm is used for such models to distribute active power, thereby improving the control accuracy, rapidity and stability of the automatic power generation control system and the primary frequency modulation system.

[0053] 2. The present invention adopts the idea of ​​step-by-step regulation, which can improve the response speed of the system and smoothly transition to the load-balanced operating state after reaching the system target value. During the regulation process, the demand for energy storage to reduce peak loads and fill valleys is also considered, thereby improving system stability and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 is a system structure diagram of the present invention;

[0055] Figure 2 Update the model data flow chart for the present invention;

[0056] Figure 3 This is a flow chart of the first step of power regulation of the present invention;

[0057] Figure 4 This is the second step flow chart of power regulation of the present invention. DETAILED DESCRIPTION

[0058] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0059] Embodiment 1:

[0060] like Figure 1 As shown, this embodiment provides a fast power control method applicable to a new energy microgrid, comprising the following steps:

[0061] Step 1: Unify the modeling of all power generation equipment and energy storage equipment in the microgrid, generally including battery clusters, wind turbine inverters, and photovoltaic data collectors. The generated model includes parameters such as rated active power, actual operating active power, adjustable upper and lower limits of active power, maximum power change rate, and expected power. Unless otherwise specified, the power in the following text refers to active power.

[0062] Step 2: The system updates the parameters in the model in real time. This step is executed periodically during the system operation. The execution period is set according to actual needs and is generally a second-level period. When executing steps 3, 4, 5, etc., this step is still executed normally and provides the device information required by other steps. In this step:

[0063] The rated active power of the equipment is generally a fixed value;

[0064] Real-time active power is obtained from each device through communication protocols;

[0065] Active power has adjustable upper and lower limits. Photovoltaic equipment is converted through irradiance provided by the irradiator, or provided by the photovoltaic data collector; wind turbine equipment is converted through wind speed of the wind tower, or provided by the wind turbine inverter; energy storage equipment is provided by the BMS system;

[0066] To calculate the expected power, first calculate the power difference between the total power target value and the peak shaving and valley filling planned power of the BMS system. If the power difference is within the total upper and lower limits of the wind and solar equipment, the energy storage device will use the peak shaving and valley filling planned power as the expected power, and other devices will evenly distribute the power difference according to the upper and lower limits of the total power; if the power difference exceeds the upper and lower limits of the wind and solar equipment, the wind and solar equipment will use the upper and lower limits as the expected power, and other power will be evenly distributed by the energy storage device according to the upper and lower limits.

[0067] Step 3: When the AGC system receives the dispatch AGC instruction, or the FPC system receives the grid connection point frequency change, or the BMS system modifies the energy storage charging and discharging target value of the system according to the energy storage management plan, the total power target value of the system changes. At this time, the total power target value calculation module recalculates the new target value.

[0068] Step 4: The wind, solar and storage power allocation algorithm allocates the power of wind, solar and storage devices based on the total power target value and the power difference to be allocated detected at the grid connection point. The allocation is divided into two stages:

[0069] The first stage is the power difference allocation, which is based on Figure 3 The process:

[0070] 4.1 Allocate all unallocated power differences to devices whose allocated power does not reach the upper and lower power limits. The allocation weight is the maximum power change rate of the device. After allocation, the allocated power of each device does not exceed the upper and lower power limits.

[0071] 4.2 Determine whether there is any unallocated power difference and whether the target values ​​of all current devices have reached the upper and lower limits of power. If all power differences have been allocated or all devices have reached the upper and lower limits, it means that the system has provided all outputs and the power is issued according to the allocated value. Otherwise, go to 4.1.

[0072] After the first stage of adjustment, when the actual power of the entire station reaches the total power target value, it enters the second stage, i.e. step 5.

[0073] Step 5: In the second stage, each device adjusts from the current power to the expected power, and the total power of the entire station remains unchanged during the adjustment process. Figure 4 As shown, first calculate the adjustment time of this step, calculate the expected active power difference of all devices, and divide it by the power change rate of the device to get the power change time. Select the maximum power change time among all devices and regard it as the adjustment time of the second stage. All devices calculate the required power change rate based on the adjustment time. The power change rate is equal to the expected active power difference of each device divided by the adjustment time. All devices perform power step-by-step adjustment based on the power change rate. When all devices reach the expected power value, this step ends.

[0074] Step 6: When step 5 is completed, the whole station and all equipment have reached the desired power regulation. At this time, if the AGC system receives the dispatch AGC instruction, or the FPC system receives the grid connection point frequency change, or the BMS system modifies the system's energy storage charging and discharging target value according to the energy storage management plan, go to step 3; if the system is limited by wind and solar resources, causing the whole station power to deviate from the total power target value, go to step 4.

[0075] Through the above steps, the system can integrate the regulation capabilities of all generator energy storage devices in operation to provide a fast and stable power regulation capability for the new energy microgrid.

[0076] like Figure 1 As shown, the specific structure of the system to which this method is applicable includes:

[0077] AGC system: AGC (automatic generation control) system, used to obtain the AGC regulation target power from the dispatching end and forward the target power to the total power target value calculation module for power calculation;

[0078] FPC system: primary frequency regulation system, used to detect the frequency of the power station grid connection point, calculate the primary frequency regulation power deviation according to the frequency change, and forward the frequency deviation to the total power target value calculation module for power calculation;

[0079] BMS system: Battery management system, used to send control instructions to the battery according to the battery charging and discharging plan and peak load shaving plan of the power station, and forward the battery operating parameters to the total power target value calculation module for power calculation;

[0080] Total power target calculation module: This module and the wind, solar and storage power allocation algorithm jointly realize the main functions of the present invention. This module is responsible for calculating the overall power calculation part of the present invention;

[0081] Wind, solar and storage power allocation module: This module and the total power target calculation module jointly realize the main functions of the present invention, and this module is responsible for the allocation and execution of power;

[0082] Wind, photovoltaic and energy storage equipment: Wind power generation equipment, photovoltaic power generation equipment and energy storage battery equipment can receive power control instructions from the power distribution module and BMS system to control the operation of the equipment and adjust the power generation;

[0083] Dispatching AGC: indicates the active power regulation target instruction sent to the power station by the regional dispatching system;

[0084] Grid connection point: refers to the access point where the various power generation equipment of the power station are connected and aggregated to the public power grid after voltage boosting.

[0085] In summary, the method of this embodiment can achieve the following beneficial effects: This method uses a unified model to uniformly manage various types of devices, thereby improving the compatibility of the system.

[0086] This method not only meets the system's high efficiency, but also improves system stability and load balancing through a two-step adjustment process. The first step is to use all devices to complete power adjustment together to ensure the rapidity of adjustment; the second step is to smoothly adjust the power of all devices to the expected power while keeping the total power unchanged. The expected power is generally a series of power generation and consumption plans such as the system power generation plan and the energy storage equipment peak shaving and valley filling plan, which can improve the stability of the execution of various plans.

[0087] Embodiment 2:

[0088] This embodiment provides a multi-type device power coordination control system suitable for microgrids, including:

[0089] Parameter acquisition module: used to describe all power generation and energy storage equipment in the new energy microgrid as multiple parameters using a unified model; and to obtain various parameters of the unified model in real time;

[0090] Total power target calculation module: used to update the total power target value of the system in real time;

[0091] Wind, solar and storage power allocation module: used to adjust the output power of all devices to the new total target power value of the entire station when the total power target value of the system changes.

[0092] The system of this embodiment can be used to implement the method described in the first embodiment.

[0093] like Figure 1 As shown, the system generally includes:

[0094] AGC system: AGC (automatic generation control) system, used to obtain the AGC regulation target power from the dispatching end and forward the target power to the total power target value calculation module for power calculation;

[0095] FPC system: primary frequency regulation system, used to detect the frequency of the power station grid connection point, calculate the primary frequency regulation power deviation according to the frequency change, and forward the frequency deviation to the total power target value calculation module for power calculation;

[0096] BMS system: Battery management system, used to send control instructions to the battery according to the battery charging and discharging plan and peak load shaving plan of the power station, and forward the battery operating parameters to the total power target value calculation module for power calculation;

[0097] Total power target calculation module: This module and the wind, solar and storage power allocation algorithm jointly realize the main functions of the present invention. This module is responsible for calculating the overall power calculation part of the present invention;

[0098] Wind, solar and storage power allocation module: This module and the total power target calculation module jointly realize the main functions of the present invention, and this module is responsible for the allocation and execution of power;

[0099] Wind, photovoltaic and energy storage equipment: Wind power generation equipment, photovoltaic power generation equipment and energy storage battery equipment can receive power control instructions from the power distribution module and BMS system to control the operation of the equipment and adjust the power generation;

[0100] Dispatching AGC: indicates the active power regulation target instruction sent to the power station by the regional dispatching system;

[0101] Grid connection point: refers to the access point where the various power generation equipment of the power station are connected and aggregated to the public power grid after voltage boosting.

[0102] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.

[0103] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0104] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0105] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0106] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A multi-type device power coordination control method suitable for microgrids, characterized in that: The following steps are involved: For all power generation and energy storage equipment in the new energy microgrid, a unified model is used to describe multiple parameters; and various parameters of the unified model are obtained in real time; Update the total power target value of the system in real time; When the total power target value of the system changes, the output power of all devices is adjusted to the new total target power value of the entire station; Methods for adjusting the output power of all devices to a new total target power value of the entire station include: The power of wind, solar and storage equipment is allocated based on the total power target value and the calculated power difference to be allocated detected at the grid connection point; Adjust from current power to expected power, keeping the total power of the entire station unchanged during the adjustment process; Methods for adjusting the current power to the expected power and keeping the total power of the entire station unchanged during the adjustment process include: Calculate the adjustment time of this step, calculate the expected active power difference of all devices, and divide it by the power change rate of the device to obtain the power change time; Select the maximum power change time among all devices as the adjustment time of the second stage; Control all devices to calculate the required power change rate according to the adjustment time. The power change rate is equal to the difference between the expected active power of each device and the adjustment time; All devices adjust the power in steps according to the power change rate until all devices reach the expected power value; The method for calculating the adjustment time of this step is: calculate the time required for all devices to adjust from the current power to the expected power according to the maximum power change rate, and select the maximum value of the adjustment time required for each device as the adjustment time of this stage.

2. The method for coordinated power control of multiple types of devices applicable to a microgrid according to claim 1, characterized in that: The unified model contains the following parameters: Rated power, real-time power, adjustable upper and lower limits of power, maximum power change rate, and expected power.

3. The method for coordinated power control of multiple types of devices applicable to a microgrid according to claim 2, characterized in that: The method for obtaining various parameters of the unified model in real time comprises the following steps: Obtain rated power, real-time power, adjustable upper and lower limits of power, maximum power change rate, and expected power; Methods for obtaining the rated power include obtaining it from the equipment manufacturer's manual; Methods for obtaining real-time power include reading through protocol; Methods for obtaining the upper and lower limits of adjustable power include: If the device is a power generation device, the upper and lower limits of the adjustable power are the maximum or minimum output power that the current device can achieve based on the current wind and solar resources. If the device is an energy storage device, the upper and lower limits of the adjustable power are the maximum power allowed for charging and discharging of the current energy storage device. The maximum power change rate is the maximum change speed of the real-time power of the device in unit time under the current working condition.

4. The method for coordinated power control of multiple types of devices applicable to a microgrid according to claim 3 is characterized in that: The method for obtaining the expected power includes: Calculate the power difference between the total power target value and the peak-shaving and valley-filling planned power of the BMS system. If the power difference is within the total adjustable upper and lower limits of the wind and solar equipment, the peak-shaving and valley-filling requirements of the energy storage equipment and the total power target are met at the same time. At this time, the expected power of the energy storage device is the planned power for peak shaving and valley filling, and the expected power of the wind and solar devices is the remaining power evenly distributed according to the upper and lower limits of the wind and solar adjustable limits; If the power difference exceeds the upper and lower limits of wind and solar equipment, the power generation capacity of wind and solar equipment will be fully utilized to give priority to meeting the total power target, and secondly, the peak shaving and valley filling needs of energy storage equipment will be met as much as possible; at this time, the expected power of wind and solar equipment is the adjustable upper and lower limits, and the expected power of the energy storage equipment is the remaining power, which is evenly distributed according to the adjustable upper and lower limits of the energy storage equipment.

5. The method for coordinated power control of multiple types of devices applicable to a microgrid according to claim 1, characterized in that: The method for updating the total power target value of the system in real time includes: When the dispatching AGC instruction is received, or the FPC system receives the frequency change of the grid connection point, or the BMS system modifies the system's energy storage charging and discharging target value according to the energy storage management plan, the system's total power target value changes, and the new system total power target value is recalculated.

6. The method for coordinated power control of multiple types of devices applicable to a microgrid according to claim 1, characterized in that: The method for allocating power of wind, solar and storage devices based on the total power target value and the power difference to be allocated detected at the grid connection point includes the following steps: Step A: Obtaining the unallocated power difference; Step B: Determine whether there is an unallocated power difference, if so, jump to step C; otherwise jump to step E; Step C: Allocate all unallocated power differences to devices whose allocated power does not reach the upper and lower power limits, and the allocation weight is the maximum power change rate of the device; Step D: Determine whether the power allocation of all devices has reached the upper and lower limits. If yes, jump to step E; otherwise, jump to step A. Step E: Send power according to the allocated value to control the output power of the device; Step F: Determine whether the actual power of the entire station reaches the total power target value. If yes, maintain the current power; otherwise, jump to step A.

7. A multi-type device power coordination control system suitable for a microgrid for executing the method according to any one of claims 1 to 6, characterized in that: include: Parameter acquisition module: used to describe all power generation and energy storage equipment in the new energy microgrid as multiple parameters using a unified model; and to obtain various parameters of the unified model in real time; Target value module: used to update the total power target value of the system in real time; Adjustment module: used to adjust the output power of all devices to the new total target power value of the entire station when the total power target value of the system changes.

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