Power control method, controller, power conversion system and energy storage system

Abstract

The application relates to a power control method, a controller, a power conversion system and an energy storage system. The method comprises: in the case that a scheduling power value indicated by a power scheduling instruction is less than a first power threshold value, controlling a plurality of power conversion units to operate in a first mode, the first mode comprising: part of the plurality of power conversion units entering a standby state, and another part of the plurality of power conversion units operating at a target power value; the first power threshold value is determined based on an efficiency inflection point power value of the power conversion unit; and the target power value is greater than the efficiency inflection point power value. The method can improve the overall charge-discharge cycle efficiency of the power conversion system in a small power scenario.

Description

Technical Field

[0001] This application relates to the field of power conversion technology, and in particular to a power control method, a controller, a power conversion system, and an energy storage system. Background Technology

[0002] In related technologies, a power conversion system (PCS) or other power conversion system that connects energy storage devices and the power grid generally includes multiple power conversion devices connected in parallel, and each power conversion device includes multiple power conversion units connected in parallel.

[0003] For power conversion units using switching transistors, in low-power applications, their efficiency is significantly affected by the decrease in output power as switching losses and fixed losses increase. When the output power of the power conversion unit decreases to a certain level, the efficiency drops drastically. Therefore, in related technologies, the power conversion system suffers from excessively low efficiency when the charging and discharging power is too low. Summary of the Invention

[0004] Therefore, it is necessary to provide a power control method, controller, power conversion system, and energy storage system that can improve the working efficiency of the power conversion system in scenarios where the charging and discharging power of the power conversion system is too low, in order to address the above-mentioned technical problems.

[0005] In a first aspect, this application provides a power control method for a power conversion system, the power conversion system including multiple power conversion units, the method comprising:

[0006] When the scheduled power value indicated by the power scheduling command is less than the first power threshold, multiple power conversion units are controlled to operate in a first mode. The first mode includes some power conversion units entering a standby state, and another part of the power conversion units operating according to the target power value. The first power threshold is determined based on the efficiency inflection point power value of the power conversion unit, and the target power value is greater than the efficiency inflection point power value.

[0007] In one embodiment, controlling multiple power conversion units to operate in a first mode includes:

[0008] Generate a first switching instruction, which includes a target power value;

[0009] Based on the first switching command, multiple power conversion units are controlled to switch from the second mode to the first mode for operation; the second mode includes multiple power conversion units operating according to the scheduled power value.

[0010] In one embodiment, the power conversion device includes a first number of power conversion units, and the number of power conversion units operating in the first mode according to the target power value is a second number.

[0011] Generate the first switching instruction, including:

[0012] Based on the scheduling power value, the first quantity, and the efficiency inflection point power value, the second quantity is obtained. The second quantity is directly proportional to the scheduling power value and the first quantity, and inversely proportional to the efficiency inflection point power value.

[0013] The overall power value of the power conversion system is obtained by multiplying the scheduled power value and the first quantity.

[0014] The target power value is obtained based on the overall power value and the second quantity.

[0015] In one embodiment, a second quantity is obtained based on the scheduling power value, the first quantity, and the efficiency inflection point power value, including:

[0016] The second quantity is determined based on the first ratio between the overall power value and the efficiency inflection point power value.

[0017] In one embodiment, determining the second quantity based on a first ratio between the overall power value and the efficiency inflection point power value includes:

[0018] The first ratio is rounded down to obtain the second quantity.

[0019] In one embodiment, determining the second quantity based on a first ratio between the overall power value and the efficiency inflection point power value includes:

[0020] The first ratio is rounded down to obtain the middle value;

[0021] If the intermediate value is greater than the second ratio, the intermediate value is determined as the second quantity, and the second ratio is the ratio between the overall power value and the rated power value corresponding to the power conversion unit.

[0022] If the median value is less than or equal to the second ratio, the second ratio is rounded up to obtain the second quantity.

[0023] In one embodiment, the first switching instruction includes: a preset scheduling duration;

[0024] Based on the first switching command, multiple power conversion units are controlled to switch from the second mode to the first mode of operation, including:

[0025] The output power of some power conversion units among multiple power conversion units is controlled to reach zero from the scheduled power value within a preset scheduling time, and the output power of another part of the power conversion units among multiple power conversion units is controlled to reach the target power value from the scheduled power value within a preset scheduling time, so that the power conversion system keeps the output power change value less than a constant threshold within the preset scheduling time.

[0026] In one embodiment, the first switching instruction further includes a first gradient step size and a second gradient step size;

[0027] Generate the first switching instruction, including:

[0028] The first gradient step size is determined based on the scheduling power value, the preset scheduling duration, and the adjustment time step.

[0029] The second gradient step size is determined based on the scheduled power value, the target power value, the preset scheduling duration, and the adjustment time step.

[0030] Controlling the output power of a portion of multiple power conversion units to reach zero from the scheduled power value within a preset scheduling time, and controlling the output power of another portion of multiple power conversion units to reach the target power value from the scheduled power value within a preset scheduling time, includes:

[0031] The output power values ​​of some power conversion units among multiple power conversion units are controlled to reach zero from the scheduled power value according to the first gradient step size and the adjustment time step size, respectively.

[0032] The output power value of another part of the power conversion units in the multiple power conversion units is controlled to reach the target power value from the scheduled power value according to the second gradient step size and the adjustment time step size.

[0033] In one embodiment, the method further includes:

[0034] When multiple power conversion units are controlled to operate in the first mode, if the scheduled power value is greater than the second power threshold, the multiple power conversion units are controlled to switch from the first mode to the second mode. The second mode includes multiple power conversion units operating according to the scheduled power value, and the second power threshold is greater than or equal to the first power threshold.

[0035] Secondly, this application also provides a power control method, which is used in a first power conversion unit in a power conversion system. The first power conversion unit is any one of a plurality of power conversion units included in the power conversion system, and the power conversion units are communicatively connected to each other. The method includes:

[0036] When the scheduled power value indicated by the power scheduling command is less than the first power threshold, multiple power conversion units are controlled to operate in a first mode. The first mode includes some of the power conversion units entering a standby state, and another part of the power conversion units operating according to a target power value, which is greater than the first power threshold. The first power threshold is determined based on the efficiency inflection point power of the power conversion unit.

[0037] Thirdly, this application also provides a power controller for a power conversion system. The power conversion system includes multiple power conversion units, and the power controller is communicatively connected to each power conversion unit. When the scheduled power value indicated by the power scheduling command is less than a first power threshold, the power controller controls the multiple power conversion units to operate in a first mode. The first mode includes some of the multiple power conversion units entering a standby state, and another part of the multiple power conversion units operating according to a target power value. The first power threshold is determined based on the efficiency inflection point power value of the power conversion unit, and the target power value is greater than the efficiency inflection point power value.

[0038] Fourthly, this application also provides a power controller for a first power conversion unit in a power conversion system. The first power conversion unit is any one of a plurality of power conversion units included in the power conversion system. The power conversion units are communicatively connected to each other. The power controller is used to control the plurality of power conversion units to operate in a first mode when the scheduling power value indicated by the power scheduling command is less than a first power threshold. The first mode includes some of the power conversion units entering a standby state, and another part of the power conversion units operating according to a target power value, which is greater than the first power threshold. The first power threshold is determined based on the efficiency inflection point power of the power conversion unit.

[0039] Fifthly, this application also provides a power conversion system. The power conversion system includes a controller and a plurality of power conversion units as provided in the third and fourth aspects.

[0040] Sixthly, this application also provides an energy storage system. The energy storage system includes an energy storage device and the power conversion system provided in the fifth aspect above.

[0041] In the aforementioned power control method, controller, power conversion system, and energy storage system, when the dispatch power value indicated by the power dispatch command is less than the first power threshold, the working efficiency of each power conversion unit will be significantly reduced. The above embodiment controls some of the power conversion units in the multiple power conversion units to enter a standby state, while another part of the power conversion units in the multiple power conversion units operate at a target power value greater than the efficiency inflection point power value. This allows the power conversion units operating in the first mode to maintain a higher working efficiency and ensures that the overall output power of the power conversion system meets the requirements of the power dispatch command, thereby improving the overall charge and discharge cycle efficiency of the power conversion system in low-power scenarios. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments or related technologies of this application, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 This is a diagram illustrating the application environment of the power control method in one embodiment;

[0044] Figure 2 This is a diagram illustrating the application environment of the power control method in another embodiment;

[0045] Figure 3 This is a schematic diagram illustrating the power-efficiency relationship of a DC-AC converter circuit based on DAB topology in one embodiment.

[0046] Figure 4 This is a flowchart illustrating a power control method in one embodiment;

[0047] Figure 5 This is a flowchart illustrating the step of generating the first switching instruction in one embodiment;

[0048] Figure 6 This is a diagram of the internal structure of an electronic device in one embodiment. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0050] The power control method provided in this application embodiment can be applied to, for example, Figure 1The application environment shown. The power conversion system includes multiple power conversion devices connected in parallel, and each power conversion device includes multiple power conversion units connected in parallel. Figure 1 The solid lines shown represent power transmission lines, and the dashed lines represent communication lines; as shown... Figure 1 As shown, each power conversion unit is connected to the power grid, and the data acquisition device is communicatively connected to each power conversion device and the power grid. For example, the data acquisition device is connected to each power conversion device, and the power conversion device collects the operating data of each power conversion unit and sends it to the data acquisition device. Additionally, the power conversion device sends control data issued by the data acquisition device to each power conversion unit. Furthermore, for another example, the data acquisition device is communicatively connected to each power conversion unit within each power conversion device. The communication connections involved in this application embodiment can be wired, wireless, or a hybrid of wired and wireless communication. Wired communication can employ PLC (Power Line Communication), RS485, or Ethernet communication methods.

[0051] For example, the power conversion device is an energy storage converter unit, and each power conversion device includes three parallel power conversion units, which are single-phase DC-AC conversion circuits. The data acquisition device may include electrical sensors, a control module, and a communication module. For example, the electrical sensors are connected to the AC bus of the power conversion system, and the electrical sensors may include voltage transformers or current transformers; the control module may be a PLC (Programmable Logic Controller) or MCU (Microcontroller Unit) controller; the communication module may support wired communication protocols and / or wireless communication protocols (such as 4G / 5G, Wi-Fi, LoRa) and other communication protocols.

[0052] In one exemplary embodiment, the provided power control method can also be applied to, for example, Figure 2 In the application scenario shown, the power conversion system includes multiple power conversion units connected in parallel, and the data acquisition device is connected to each power conversion unit through communication.

[0053] Taking a DC-AC converter circuit based on a DAB (Dual Active Bridge) topology as an example, this embodiment aims to address the technical problem it addresses. Figure 3 As shown, in low-power scenarios, the efficiency of a DC-AC converter circuit based on DAB topology is significantly affected by the increase in the proportion of switching losses and fixed losses. For example, at 20% of the rated power (P...n For DC-AC converters based on DAB topology, this is an efficiency inflection point; when the output power is less than 20% of the rated power, the efficiency of DC-AC converters based on DAB topology drops sharply. Figure 1 As shown or Figure 2 In the application environment, the output power of each power conversion unit is scheduled by the upper-level module (i.e., the data acquisition device). In a single-phase connection scenario, the total output power of the entire power conversion system is evenly distributed among the power conversion units. In a three-phase connection scenario, each power conversion unit is connected to the corresponding phase circuit according to the settings. The output phases of each power conversion unit are different, but the output power is the same, based on the even distribution of the total output power of the entire power conversion system. Regardless of the scenario, if the charging and discharging power of the entire power conversion system is too low, the working efficiency of the power conversion units will be too low, resulting in low working efficiency of the entire power conversion system. This application solves the problem of low working efficiency of the power conversion system in scenarios where the charging and discharging power of the power conversion system is too low through the following embodiments.

[0054] In one exemplary embodiment, a power control method is provided, which is applied to Figure 1 As shown or Figure 2 The following explanation uses a power conversion system as an example. For instance, this method can be applied to the data acquisition device of a power conversion system; it can also be applied to the processor of any power conversion device in the power conversion system; and it can also be applied to any power conversion unit among the multiple power conversion units included in the power conversion system.

[0055] The power control method provided in this embodiment includes: when the scheduled power value indicated by the power scheduling command is less than a first power threshold, controlling multiple power conversion units to operate in a first mode. The first mode includes some power conversion units entering a standby state, and another portion of the power conversion units operating according to a target power value. The first power threshold is determined based on the efficiency inflection point power value of the power conversion unit, and the target power value is greater than the efficiency inflection point power value.

[0056] In this context, the power dispatch instruction refers to the instruction received by the power conversion system, which instructs each power conversion unit to output its working power according to the dispatched power value. The dispatched power value refers to the amount of power output by the power conversion unit as the generating unit.

[0057] For example, the process of a power conversion system obtaining a power dispatch instruction includes: the power conversion system receiving a power dispatch instruction sent by the BMS (Battery Management System) of the energy storage device.

[0058] The efficiency inflection point power refers to the inflection point where the efficiency of the power conversion unit drops sharply as the output power decreases. For example, Figure 3 The efficiency inflection point power of the DC-AC converter circuit based on the DAB topology shown is 20% of the rated power of the DC-AC converter circuit. For example, the efficiency inflection point power of power conversion units using other topologies can be obtained experimentally for that type of power conversion unit. The ratio between the efficiency inflection point power and the rated power can be different for power conversion units with different topologies.

[0059] Optionally, the first power threshold is equal to the efficiency inflection point power value. Optionally, the first power threshold is slightly larger than the efficiency inflection point power value; for example, if the efficiency inflection point power is 20% of the rated power, the first power threshold can be set to 21% or 25% of the rated power. Optionally, the first power threshold is slightly smaller than the efficiency inflection point power value; for example, if the efficiency inflection point power is 20% of the rated power, the first power threshold can be set to 18% or 19% of the rated power.

[0060] The standby state refers to the power conversion unit's output power being zero, while the power conversion unit's communication and control functions are still in operation.

[0061] When the power scheduling value indicated by the power scheduling command is less than the first power threshold, the working efficiency of each power conversion unit will be greatly reduced. The above embodiment controls some of the power conversion units in the multiple power conversion units to enter the standby state, and another part of the power conversion units in the multiple power conversion units to operate at a target power value greater than the efficiency inflection point power value. This allows the power conversion units operating in the first mode to be at a higher working efficiency and ensures that the overall output power of the power conversion system meets the requirements of the power scheduling command, thereby improving the overall charge and discharge cycle efficiency of the power conversion system in low-power scenarios.

[0062] In one exemplary embodiment, please refer to Figure 4 The provided power control method includes steps 402 and 404, whereby:

[0063] Step 402: Generate the first switching instruction.

[0064] The first switching instruction includes the target power value.

[0065] Step 404: Based on the first switching command, control multiple power conversion units to switch from the second mode to the first mode for operation.

[0066] The second mode involves multiple power conversion units operating according to a scheduled power value. When the scheduled power value indicated by the power scheduling command is greater than or equal to a first power threshold, the multiple power conversion units in the power conversion system operate in the second mode, meaning each power conversion unit operates according to the scheduled power value. In the second mode, each power conversion unit operates according to the received scheduled power value. When the scheduled power value indicated by the power scheduling command is less than the first power threshold, each power conversion unit operates in the second mode. For example, each power conversion unit still receives the scheduled power value indicated by the power scheduling command, but ignores the scheduled power value and, in response to the first switching command, enters the first mode, i.e., enters a standby state or enters a state of operating according to the target power value.

[0067] In this application, the power conversion system includes a first number of power conversion units, and the number of power conversion units operating in the first mode according to the target power value is a second number.

[0068] In an exemplary embodiment, the target power value is a preset power value that is greater than the efficiency inflection point power value. When the scheduled power value indicated by the power scheduling instruction is less than the first power threshold, the overall power value that the power conversion system needs to output is calculated based on the scheduled power value and the first quantity. Based on the overall power value and the target power value, the second quantity of power conversion units that need to be operated is determined. From the multiple power conversion units, the second quantity of power conversion units are selected in a round-robin or random order, so that these power conversion units operate according to the target power value, and the remaining power conversion units enter the standby state.

[0069] In one exemplary embodiment, a second quantity and a target power value are determined based on the scheduled power value indicated by the power scheduling instruction, a first quantity, and an efficiency inflection point power value. In this embodiment, please refer to... Figure 5 The provided power control method involves the process of generating the first switching command. For example... Figure 5 As shown, the process includes steps 502 to 506, wherein:

[0070] Step 502: Based on the scheduling power value, the first quantity, and the efficiency inflection point power value, obtain the second quantity.

[0071] The second quantity is directly proportional to the scheduling power value and the first quantity, while the second quantity is inversely proportional to the efficiency inflection point power value.

[0072] With the number of power conversion units in the power conversion system remaining constant, the smaller the scheduled power value, the less the overall output power demand of the power conversion system. In the first mode, the output power of the power conversion units participating in the operation needs to be greater than the target power value. Therefore, the number of power conversion units that need to operate according to the target power value is also less. That is, the second quantity is proportional to the scheduled power value.

[0073] When the scheduled power value is less than the first power threshold and the scheduled power value remains unchanged, the smaller the first number of power conversion units in the power conversion system, the smaller the overall output power demand of the power conversion system will be, since the scheduled power value is the output power scheduling value for each power conversion unit. Therefore, the number of power conversion units that need to operate according to the target power value will be less, that is, the second number is proportional to the first number.

[0074] Under the premise that the scheduled power value is less than the first power threshold, the scheduled power value and the first quantity remain unchanged, and the overall output power value of the power conversion system remains unchanged. The larger the efficiency inflection point power value corresponding to the power conversion unit, the larger the target power value is. Therefore, the fewer power conversion units need to operate according to the target power value, that is, the second quantity is inversely proportional to the efficiency inflection point power value.

[0075] Step 504: Obtain the overall power value corresponding to the power conversion system based on the product of the scheduled power value and the first quantity.

[0076] Step 506: Obtain the target power value based on the overall power value and the second quantity.

[0077] The target power value is obtained based on the ratio of the overall power value to the second quantity.

[0078] In one possible implementation of this embodiment, the process of obtaining the second quantity based on the scheduling power value, the first quantity, and the efficiency inflection point power value includes: determining the second quantity based on the first ratio between the overall power value and the efficiency inflection point power value.

[0079] In one alternative implementation, the first ratio is rounded down to obtain the second quantity.

[0080] In this implementation, the second quantity Where n represents the first quantity, P ref P represents the dispatch power value. g This represents the efficiency inflection point power value. Using this implementation method, the second quantity ensures that the target power value determined based on this second quantity is greater than the efficiency inflection point power value.

[0081] In one alternative implementation, the process of determining the second quantity based on a first ratio between the overall power value and the efficiency inflection point power value includes steps A1 to A3, wherein:

[0082] Step A1: Round down the first ratio to obtain the intermediate value.

[0083] In this implementation, the intermediate value .

[0084] Step A2: If the median value is greater than the second ratio, the median value is determined as the second quantity.

[0085] Step A3: If the intermediate value is less than or equal to the second ratio, round the second ratio up to obtain the second quantity.

[0086] The second ratio is the ratio between the overall power value and the rated power value of the power conversion unit, as shown in the following formula: Second Ratio , where P n This indicates the rated power value corresponding to the power conversion unit.

[0087] If the median value is greater than the second ratio, the median value is determined as the second quantity. If the median value is less than or equal to the second ratio, the second ratio is rounded up to obtain the second quantity. Thus, the second quantity is determined based on the second ratio. In this way, the output power of a single power conversion unit participating in operation is constrained by the second ratio to not exceed its rated power P. n .

[0088] The power control method provided in the above embodiments calculates the second number of power conversion units participating in operation in the first mode based on the scheduling power value and efficiency inflection point power value indicated by the power scheduling instruction, and obtains the target power value for the operation of the power conversion units, so that the second number of units participating in operation in the first mode and the target power value are more in line with the power scheduling requirements shown by the current power scheduling instruction.

[0089] In an exemplary embodiment, the first switching instruction includes a preset scheduling duration. In this embodiment, the process of controlling multiple power conversion units to switch from a second mode to a first mode based on the first switching instruction includes: controlling the output power value of some of the power conversion units to reach zero from a scheduled power value within the preset scheduling duration, and controlling the output power value of another portion of the power conversion units to reach a target power value from a scheduled power value within the preset scheduling duration, so that the power conversion device maintains an output power change value less than a constant threshold within the preset scheduling duration.

[0090] When the power conversion system receives a power scheduling command, it first controls each power conversion unit to operate according to the scheduling power value indicated by the power scheduling command, so that the power conversion system first meets the power scheduling requirements; then it generates a first switching command, and according to the first switching command, within a preset scheduling time, it causes each power conversion unit to gradually reach the standby state required by the first mode or the state of operating according to the target power value.

[0091] In one possible implementation, the first switching instruction further includes a first gradient step size and a second gradient step size; correspondingly, the process of generating the first switching instruction further includes: determining the first gradient step size based on the scheduling power value, the preset scheduling duration and the adjustment time step size, and determining the second gradient step size based on the scheduling power value, the target power value, the preset scheduling duration and the adjustment time step size.

[0092] For example, the time step can be adjusted based on the operating frequency of the power conversion unit.

[0093] In this embodiment, the process of controlling the output power value of some power conversion units among multiple power conversion units to reach zero within a preset scheduling time, and controlling the output power value of another part of the power conversion units among multiple power conversion units to reach the target power value from the scheduled power value within a preset scheduling time includes: controlling the output power value of some power conversion units among multiple power conversion units to reach zero from the scheduled power value according to a first gradient step size and an adjustment time step size respectively; and controlling the output power value of another part of the power conversion units among multiple power conversion units to reach the target power value from the scheduled power value according to a second gradient step size and an adjustment time step size respectively.

[0094] Specifically, the number of adjustments within the preset scheduling duration can be determined based on the preset scheduling duration and adjustment time step. Based on the ratio of the scheduled power value to the number of adjustments, the first gradient step size corresponding to each adjustment when the scheduled power value is adjusted to zero is obtained. The difference between the scheduled power value and the target power value is acquired. Then, based on the ratio of the difference to the number of adjustments, the second gradient step size corresponding to each adjustment during the process of adjusting the scheduled power value to the target power value is obtained. Thus, the output power of a third number of power conversion units is gradually reduced according to the first gradient step size and adjustment time step, and the output power of a second number of power conversion units is gradually increased according to the second gradient step size and adjustment time step, ensuring that the overall output power value of the power conversion system remains unchanged or almost unchanged during each adjustment process.

[0095] For example, the constant threshold ranges from 0.1W to 10W.

[0096] In an exemplary embodiment, the provided power control method further includes: when controlling multiple power conversion units to operate in a first mode, if the scheduled power value is greater than a second power threshold, then controlling the multiple power conversion units to switch from the first mode to the second mode. The second power threshold is greater than or equal to the first power threshold.

[0097] In one possible implementation, the second power threshold is equal to the first power threshold. That is, when each power conversion unit is operating in the first mode, if the power scheduling value indicated in the received power scheduling instruction is detected to be greater than the first power threshold, then each power conversion unit is controlled to operate according to the power scheduling value.

[0098] In one possible implementation, the second power threshold is greater than the first power threshold. That is, when each power conversion unit is operating in the first mode, if the power scheduling value indicated in the received power scheduling instruction is greater than the first power threshold but less than or equal to the second power threshold, then each power conversion unit is controlled to continue operating in the first mode. If the power scheduling value indicated in the received power scheduling instruction is greater than the second power threshold, then each power conversion unit is controlled to switch from the first mode to the second mode.

[0099] For example, the process of controlling multiple power conversion units to switch from a first mode to a second mode includes: generating a second switching instruction, and controlling the multiple power conversion units to switch from the first mode to the second mode based on the second switching instruction.

[0100] In one exemplary embodiment, a power control method is provided, which is applied to... Figure 1 As shown or Figure 2 The power conversion system shown is used as an example for illustration; the power conversion system includes a first number of power conversion units. The method includes steps S2 to S8, wherein:

[0101] Step S2: Receive power scheduling instructions and control each power conversion unit to operate according to the scheduled power value indicated by the power scheduling instructions.

[0102] Step S4: If the scheduled power value indicated by the power scheduling instruction is less than the first power threshold, a first switching instruction is generated. The first switching instruction includes a target power value, a second quantity, a preset scheduling duration, a first gradient step size, and a second gradient step size. The first power threshold is determined based on the efficiency inflection point power value of the power conversion unit, and the target power value is greater than the efficiency inflection point power value.

[0103] Optionally, the process of generating the first switching instruction includes: rounding down the first ratio between the overall power value and the efficiency inflection point power value to obtain an intermediate value; if the intermediate value is greater than a second ratio, determining the intermediate value as a second quantity, where the second ratio is the ratio between the overall power value and the rated power value corresponding to the power conversion unit; if the intermediate value is less than or equal to the second ratio, rounding up the second ratio to obtain a second quantity; determining a first gradient step size based on the scheduled power value, the preset scheduling duration, and the adjustment time step size; and determining a second gradient step size based on the scheduled power value, the target power value, the preset scheduling duration, and the adjustment time step size.

[0104] Step S6: Control the output power values ​​of a second number of power conversion units in the plurality of power conversion units to reach zero from the scheduled power value according to the first gradient step size and the adjustment time step size respectively; and control the output power values ​​of another third number of power conversion units in the plurality of power conversion units to reach the target power value from the scheduled power value according to the second gradient step size and the adjustment time step size respectively, wherein the second number plus the third number equals the first number.

[0105] Step S8: When controlling multiple power conversion units to operate in the first mode, if the scheduled power value is greater than the second power threshold, then control the multiple power conversion units to switch from the first mode to the second mode.

[0106] In one exemplary embodiment, a power control method is provided, which is applied to... Figure 1 As shown or Figure 2 The method is illustrated using the first power conversion unit in the power conversion system as an example. The first power conversion unit is any one of the multiple power conversion units included in the power conversion system, and the power conversion units are communicatively connected. The method includes: when the scheduled power value indicated by the power scheduling command is less than a first power threshold, controlling the multiple power conversion units to operate in a first mode. The first mode includes some of the multiple power conversion units entering a standby state, and another portion of the multiple power conversion units operating at a target power value, which is greater than the first power threshold. The first power threshold is determined based on the efficiency inflection point power of the power conversion unit.

[0107] For example, the power conversion unit includes an external communication module and a unit communication module. The external communication module is used to connect to control devices outside the unit, such as data acquisition devices and BMS, and is used to receive power scheduling commands. The unit communication module is used to communicate with other power conversion units.

[0108] In this embodiment, the first power conversion unit is used as the main unit to detect the relationship between the scheduled power value and the first power threshold. When the scheduled power value is detected to be less than the first power threshold, a control signal is sent to other power conversion units to control some power conversion units in the power conversion system to enter the standby state, and another part of the power conversion units among the multiple power conversion units operate according to the target power value to improve the overall charge and discharge cycle efficiency of the power conversion system in low power scenarios.

[0109] Optionally, when the power conversion system enters the first mode, the first power conversion unit may preferentially set itself as the power conversion unit operating according to the target power value. Optionally, when the power conversion system enters the first mode, the first power conversion unit may, after determining the number of power conversion units operating according to the target power value, select some power conversion units to operate according to the target power value according to a preset strategy or a random method, while other power conversion units enter a standby state.

[0110] In one possible way, Figure 1 In the application scenario shown, a first power conversion unit is determined for each power conversion device, and the power conversion units other than the first power conversion unit in the power conversion device are used as second power conversion units. The first power conversion unit in each power conversion device is determined to be the power conversion unit that enters the standby state and the power conversion unit that operates according to the target power value in the first mode.

[0111] In one possible implementation, Figure 1 In the application scenario shown, only one first power conversion unit is set for the entire power conversion system. Given a determined number of power conversion units operating at the target power value, the preset strategy includes prioritizing ensuring that all power conversion units in as many power conversion devices as possible are operating at the target power value. For example, Figure 1 In the application scenario shown, each power conversion device includes three power conversion units. In the first mode, the number of power conversion units operating according to the target power value is six. Therefore, two power conversion devices are determined, and all power conversion units in these two power conversion devices are controlled to operate according to the target power value.

[0112] In one possible implementation, Figure 1 In the application scenario shown, only one first power conversion unit is set for the entire power conversion system. Given a determined number of power conversion units operating at the target power value, the preset strategy includes prioritizing ensuring that as many power conversion devices as possible have power conversion units operating at the target power value. For example, Figure 1In the application scenario shown, there are a total of five power conversion devices, each of which includes three power conversion units. In the first mode, the number of power conversion units operating according to the target power value is six. Therefore, each power conversion device has one power conversion unit operating according to the target power value. Then, a power conversion device is selected so that the second power conversion unit in it operates according to the target power value.

[0113] The above preset strategies are just examples; you can set preset strategies according to specific application needs.

[0114] The power control method applied to the first power conversion unit is identical in concept to the power control method applied to the power conversion system described above, except that the executing subject is different. Therefore, other embodiments of the power control method applied to the first power conversion unit are limited by the power control method applied to the power conversion system described above and will not be repeated here.

[0115] It should be understood that although the steps in the flowcharts of the above embodiments are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the above embodiments may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0116] It is understood that the term "based on" as used in this application is used to describe one or more factors that influence the determination, but does not exclude other factors that may influence the determination. For example, the phrase "determine A based on B" means that the determination of A can be based entirely or at least partially on factor B. That is, B is a factor that influences the determination of A, but does not exclude the fact that the determination of A is also based on C.

[0117] Based on the same inventive concept, this application also provides a power controller for implementing the power control method described above. The solution provided by this power controller is similar to the implementation described in the above method; therefore, the specific limitations in one or more power controller embodiments provided below can be found in the limitations of the power control method described above, and will not be repeated here.

[0118] In an exemplary embodiment, a power controller is provided for a power conversion system. The power conversion system includes multiple power conversion units. The power controller is communicatively connected to each power conversion unit. When the scheduled power value indicated by the power scheduling command is less than a first power threshold, the power controller controls the multiple power conversion units to operate in a first mode. The first mode includes some of the multiple power conversion units entering a standby state, and another part of the multiple power conversion units operating according to a target power value. The first power threshold is determined based on the efficiency inflection point power value of the power conversion unit, and the target power value is greater than the efficiency inflection point power value.

[0119] In an exemplary embodiment, the power controller is configured to generate a first switching instruction, the first switching instruction including a target power value; and control multiple power conversion units to switch from a second mode to a first mode based on the first switching instruction; the second mode includes multiple power conversion units operating according to a scheduled power value.

[0120] In an exemplary embodiment, the power conversion device includes a first number of power conversion units, and the number of power conversion units operating in the first mode according to the target power value is a second number. The power controller is used to obtain the second number based on the scheduled power value, the first number, and the efficiency inflection point power value. The second number is proportional to the scheduled power value and the first number, and inversely proportional to the efficiency inflection point power value. The overall power value corresponding to the power conversion system is obtained based on the product of the scheduled power value and the first number. The target power value is obtained based on the overall power value and the second number.

[0121] In one exemplary embodiment, the power controller is configured to determine a second quantity based on a first ratio between the overall power value and the efficiency inflection point power value.

[0122] In one exemplary embodiment, the power controller is used to round down the first ratio to obtain a second quantity.

[0123] In an exemplary embodiment, the power controller is used to round down the first ratio to obtain an intermediate value; if the intermediate value is greater than the second ratio, the intermediate value is determined as a second quantity, where the second ratio is the ratio between the overall power value and the rated power value corresponding to the power conversion unit; if the intermediate value is less than or equal to the second ratio, the second ratio is rounded up to obtain a second quantity.

[0124] In an exemplary embodiment, the first switching instruction includes a preset scheduling duration; the power controller is used to control the output power value of some power conversion units among the multiple power conversion units to reach zero from the scheduled power value within the preset scheduling duration, and to control the output power value of another part of the power conversion units among the multiple power conversion units to reach the target power value from the scheduled power value within the preset scheduling duration, so that the power conversion system keeps the output power change value less than a constant threshold within the preset scheduling duration.

[0125] In an exemplary embodiment, the first switching instruction includes: a first gradient step size and a second gradient step size; the power controller is configured to determine the first gradient step size based on the scheduled power value, a preset scheduling duration, and an adjustment time step size; determine the second gradient step size based on the scheduled power value, a target power value, a preset scheduling duration, and an adjustment time step size; control the output power values ​​of some power conversion units among the plurality of power conversion units to reach zero from the scheduled power value according to the first gradient step size and the adjustment time step size respectively; and control the output power values ​​of another portion of the power conversion units among the plurality of power conversion units to reach the target power value from the scheduled power value according to the second gradient step size and the adjustment time step size respectively.

[0126] In an exemplary embodiment, the power controller is configured to, when controlling multiple power conversion units to operate in a first mode, switch the multiple power conversion units from the first mode to a second mode if the scheduled power value is greater than a second power threshold. The second mode includes multiple power conversion units operating in accordance with the scheduled power value, and the second power threshold is greater than or equal to the first power threshold.

[0127] In an exemplary embodiment, a power controller is provided for a first power conversion unit in a power conversion system. The first power conversion unit is any one of a plurality of power conversion units included in the power conversion system. The power conversion units are communicatively connected to each other. The power controller is used to control the plurality of power conversion units to operate in a first mode when the scheduling power value indicated by the power scheduling command is less than a first power threshold. The first mode includes some of the power conversion units entering a standby state, and another part of the power conversion units operating according to a target power value, which is greater than the first power threshold. The first power threshold is determined based on the efficiency inflection point power of the power conversion unit.

[0128] The power controller applied to the first power conversion unit has the same inventive concept as the power control method applied to the power conversion system described above. Therefore, other embodiments of the power controller applied to the first power conversion unit are subject to the limitations of the power controller applied to the power conversion system described above, and will not be repeated here.

[0129] In one embodiment, a power conversion system is provided, which includes a power controller and a plurality of power conversion units as provided in the foregoing embodiments.

[0130] In one embodiment, an energy storage system is provided, which includes an energy storage device and the power conversion system described in the foregoing embodiments.

[0131] In one exemplary embodiment, an electronic device is provided, which may be an MCU, and its internal structure diagram may be as follows: Figure 6 As shown, this electronic device includes a processor, memory, input / output (I / O) interfaces, and a communication interface. The processor, memory, and I / O interfaces are connected via a system bus, and the communication interface is also connected to the system bus via the I / O interfaces. The processor provides computational and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system, computer programs, and a database. The internal memory provides the environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The database stores data required for executing the power control method. The I / O interfaces are used for exchanging information between the processor and external devices. The communication interface is used for communicating with external electronic devices or terminal devices via a network connection. When the computer program is executed by the processor, it implements a power control method.

[0132] Those skilled in the art will understand that Figure 6 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the electronic device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0133] In one embodiment, an electronic device is also provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps in the above-described method embodiments.

[0134] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon that, when executed by a processor, implements the steps in the above method embodiments.

[0135] In one embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps in the above method embodiments.

[0136] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of the relevant data must comply with relevant regulations.

[0137] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments described above. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0138] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0139] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A power control method, characterized in that, The method is used in a power conversion system, the power conversion system including multiple power conversion units, the method comprising: When the scheduled power value indicated by the power scheduling command is less than a first power threshold, the plurality of power conversion units are controlled to operate in a first mode. The first mode includes some of the power conversion units entering a standby state, and another part of the power conversion units operating according to a target power value. The first power threshold is determined based on the efficiency inflection point power value of the power conversion unit, and the target power value is greater than the efficiency inflection point power value.

2. The method according to claim 1, characterized in that, The control of the plurality of power conversion units to operate in a first mode includes: Generate a first switching instruction, wherein the first switching instruction includes the target power value; Based on the first switching instruction, the multiple power conversion units are controlled to switch from the second mode to the first mode for operation; the second mode includes multiple power conversion units operating according to the scheduled power value.

3. The method according to claim 2, characterized in that, The power conversion system includes a first number of power conversion units, and the number of power conversion units operating according to the target power value in the first mode is a second number. The generation of the first switching instruction includes: The second quantity is obtained based on the scheduling power value, the first quantity, and the efficiency inflection point power value. The second quantity is directly proportional to the scheduling power value and the first quantity, and inversely proportional to the efficiency inflection point power value. The overall power value of the power conversion system is obtained by multiplying the scheduled power value and the first quantity. The target power value is obtained based on the overall power value and the second quantity.

4. The method according to claim 3, characterized in that, The step of obtaining the second quantity based on the scheduling power value, the first quantity, and the efficiency inflection point power value includes: The second quantity is determined based on a first ratio between the overall power value and the efficiency inflection point power value.

5. The method according to claim 4, characterized in that, Determining the second quantity based on the first ratio between the overall power value and the efficiency inflection point power value includes: The first ratio is rounded down to obtain the second quantity.

6. The method according to claim 4, characterized in that, Determining the second quantity based on the first ratio between the overall power value and the efficiency inflection point power value includes: The first ratio is rounded down to obtain the median value; If the intermediate value is greater than the second ratio, the intermediate value is determined as the second quantity, and the second ratio is the ratio between the overall power value and the rated power value corresponding to the power conversion unit. If the intermediate value is less than or equal to the second ratio, the second ratio is rounded up to obtain the second quantity.

7. The method according to claim 2, characterized in that, The first switching instruction includes: a preset scheduling duration; The step of controlling the plurality of power conversion units to switch from the second mode to the first mode based on the first switching command includes: The power conversion system controls the output power value of some of the multiple power conversion units to reach zero from the scheduled power value within the preset scheduling time, and controls the output power value of another part of the multiple power conversion units to reach the target power value from the scheduled power value within the preset scheduling time, so that the power conversion system keeps the output power change value less than a constant threshold within the preset scheduling time.

8. The method according to claim 7, characterized in that, The first switching instruction also includes a first gradient step size and a second gradient step size; The generation of the first switching instruction includes: The first gradient step size is determined based on the scheduling power value, the preset scheduling duration, and the adjustment time step size. The second gradient step size is determined based on the scheduling power value, the target power value, the preset scheduling duration, and the adjustment time step size; The step of controlling the output power value of a portion of the plurality of power conversion units to reach zero from the scheduled power value within a preset scheduling time, and controlling the output power value of another portion of the plurality of power conversion units to reach the target power value from the scheduled power value within the preset scheduling time, includes: The output power values ​​of some of the power conversion units among the plurality of power conversion units are controlled to reach zero from the scheduled power value according to the first gradient step size and the adjustment time step size, respectively. The output power value of another part of the power conversion units in the plurality of power conversion units is controlled to reach the target power value from the scheduled power value according to the second gradient step size and the adjustment time step size.

9. The method according to claim 1, characterized in that, The method further includes: When the plurality of power conversion units are controlled to operate in the first mode, if the scheduled power value is greater than the second power threshold, the plurality of power conversion units are controlled to switch from the first mode to the second mode. The second mode includes the plurality of power conversion units operating in accordance with the scheduled power value, and the second power threshold is greater than or equal to the first power threshold.

10. A power control method, characterized in that, The method is used in a first power conversion unit in a power conversion system, wherein the first power conversion unit is any one of a plurality of power conversion units included in the power conversion system, and the power conversion units are communicatively connected to each other. The method includes: When the scheduled power value indicated by the power scheduling command is less than the first power threshold, the plurality of power conversion units are controlled to operate in a first mode. The first mode includes some of the power conversion units entering a standby state, and another part of the power conversion units operating according to a target power value, which is greater than the first power threshold. The first power threshold is determined based on the efficiency inflection point power of the power conversion unit.

11. A power controller, characterized in that, The power controller is used in a power conversion system, which includes multiple power conversion units. The power controller is communicatively connected to each of the power conversion units. When the scheduled power value indicated by the power scheduling command is less than a first power threshold, the power controller controls the multiple power conversion units to operate in a first mode. The first mode includes some of the multiple power conversion units entering a standby state, and another part of the multiple power conversion units operating according to a target power value. The first power threshold is determined based on the efficiency inflection point power value of the power conversion unit, and the target power value is greater than the efficiency inflection point power value.

12. A power controller, characterized in that, The power controller is used in the first power conversion unit of the power conversion system. The first power conversion unit is any one of the multiple power conversion units included in the power conversion system. The power conversion units are communicatively connected to each other. The power controller is used to control the multiple power conversion units to operate in a first mode when the scheduling power value indicated by the power scheduling command is less than a first power threshold. The first mode includes some of the multiple power conversion units entering a standby state, and another part of the multiple power conversion units operating according to a target power value. The target power value is greater than the first power threshold, and the first power threshold is determined based on the efficiency inflection point power of the power conversion unit.

13. A power conversion system, characterized in that, The power conversion system includes the controller and multiple power conversion units as described in claim 11 or 12.

14. An energy storage system, characterized in that, The energy storage system includes an energy storage device and a power conversion system as described in claim 13.

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