Direct current microgrid power supply system and control method of direct current microgrid power supply system

Abstract

The application discloses a direct-current micro-grid power supply system and a control method thereof, and relates to the technical field of direct-current micro-grids. The direct-current micro-grid power supply system comprises a voltage sampler configured to collect bus voltage of a direct-current bus; and a controller configured to: acquire a first direct-current micro-grid current and a direct-current micro-grid voltage of the direct-current micro-grid power supply system at a current sampling moment; calculate a product of the first direct-current micro-grid current and the direct-current micro-grid voltage to obtain a first direct-current micro-grid power of the direct-current micro-grid power supply system; predict a second direct-current micro-grid power of the direct-current micro-grid power supply system at a next sampling moment based on a voltage difference between the direct-current micro-grid voltage and the bus voltage, the first direct-current micro-grid current and the direct-current micro-grid voltage; and take a difference between the first direct-current micro-grid power and the second direct-current micro-grid power as droop adjustment power, and send a control instruction containing the droop adjustment power to an air conditioning device. The above method can guarantee the stability of the direct-current micro-grid.

Description

Technical Field

[0001] This application relates to the field of DC microgrid technology, and in particular to a DC microgrid power supply system and a control method for the DC microgrid power supply system. Background Technology

[0002] With the rapid development of distributed new energy sources (such as photovoltaics and energy storage), DC microgrids have become increasingly popular in building power supply and remote area power supply scenarios due to their advantages, including the elimination of frequent AC-DC conversion, high energy transmission efficiency, and adaptability to distributed power sources and DC load characteristics. Air conditioning equipment, as a high-power load, experiences power fluctuations that directly affect the power balance and voltage stability of the DC microgrid. The DC microgrid model, which supplies power to air conditioning equipment via a DC bus, has become one of the mainstream architectures for new energy power supply systems, and its operational reliability directly determines the user's electricity experience and energy utilization efficiency.

[0003] In related technologies, the adaptation control of air conditioning equipment and DC microgrids often adopts the mode of load-side voltage feedback and constant power regulation. For example, the air conditioning equipment, as the load end, detects the bus voltage of the DC bus in real time, and adapts to the power fluctuations of the DC microgrid through its own constant power operation characteristics, thereby maintaining the stability of the DC microgrid operation.

[0004] However, this technology is a reactive control method, where the air conditioning equipment only initiates current adjustment after the bus voltage has already dropped or risen (i.e., microgrid power imbalance has actually occurred). Consequently, it can still lead to problems such as increased fluctuations in DC microgrid bus voltage and persistent power imbalance, affecting the operational stability of the DC microgrid power supply system. Summary of the Invention

[0005] This application provides a control method for a DC microgrid power supply system, which can solve the problem of low operational stability of the DC microgrid power supply system.

[0006] Firstly, a DC microgrid power supply system is provided, wherein the DC microgrid power supply system is connected to air conditioning equipment via a DC bus, and the DC microgrid power supply system is used to supply power to the air conditioning equipment for operation via the DC bus. DC microgrid power supply systems include: The voltage sampler is configured to collect the DC bus voltage at the current sampling moment when the air conditioning equipment is running. The controller is configured as follows: Obtain the first DC microgrid current and DC microgrid voltage of the DC microgrid power supply system at the current sampling time; The power of the first DC microgrid power supply system is obtained by calculating the product of the first DC microgrid current and the DC microgrid voltage. Based on the voltage difference between the DC microgrid voltage and the bus voltage, the change in microgrid current during the operation of the DC microgrid power supply system is calculated. Based on the microgrid current change, the first DC microgrid current, and the DC microgrid voltage, predict the power of the second DC microgrid in the DC microgrid power supply system at the next sampling time. The difference between the power of the first DC microgrid and the power of the second DC microgrid is used as the droop adjustment power, and a control command containing the droop adjustment power is sent to the air conditioning equipment. The air conditioning equipment is configured to respond to control commands to adjust the operating power of the air conditioning equipment according to the droop adjustment power.

[0007] In the above technical solution, the bus voltage of the DC bus at the current sampling moment is collected by a voltage sampler. Combined with the current DC microgrid current and DC microgrid voltage obtained by the controller, the power of the first DC microgrid is calculated based on the power formula, providing accurate basic data support for subsequent control. Then, the change in microgrid current is calculated based on the voltage difference between the DC microgrid voltage and the bus voltage, ensuring that the calculated result reflects the dynamic trend of the microgrid current over a short period. That is, the predicted current at the next sampling moment can be directly predicted using the current first DC microgrid current and the microgrid current change describing the trend of microgrid current change. Furthermore, by using an approximately constant DC microgrid voltage and predicted current, the power of the second DC microgrid at the next sampling moment can be accurately predicted, overcoming the limitation of only being able to make post-event adjustments based on current measured parameters and achieving advance prediction of the microgrid power change trend. Then, the difference between the first and second DC microgrid power is used as the droop adjustment power, so that the adjustment signal directly corresponds to the power change demand of the microgrid, ensuring the pertinence and accuracy of the control command and avoiding system oscillations caused by blind adjustment. Finally, the air conditioning equipment responds to the control command and adjusts its operating power, enabling it to adapt to the power supply and demand status of the microgrid in advance. This mitigates the risk of power imbalance caused by power fluctuations and sudden load changes in the DC microgrid power supply system, improving the power balance capability and operational stability of the DC microgrid. Furthermore, this control method is executed by the DC microgrid power supply system, eliminating the need for the air conditioning equipment to perform data detection, deviation calculation, and decision-making autonomously. It only needs to respond to the control command to adjust its operating power, shifting the control node from passively remedying power imbalances after they occur to proactively predicting power changes before they happen. This significantly reduces the inherent delay in autonomous detection and decision-making at the air conditioning equipment end, allowing it to complete adaptive adjustments before the actual occurrence of microgrid power imbalances, ensuring the operational stability of the DC microgrid and the continuity of air conditioning equipment operation.

[0008] In one embodiment, the controller is configured to predict the power of the second DC microgrid in the DC microgrid power supply system at the next sampling time based on the microgrid current change, the first DC microgrid current, and the DC microgrid voltage. The change in microgrid current is summed with the first DC microgrid current to predict the second DC microgrid current at the next sampling time. The power of the second DC microgrid is determined by multiplying the DC microgrid voltage by the second DC microgrid current.

[0009] In the above technical solution, based on the actual first DC microgrid current and the change in microgrid current at the current sampling moment, the second DC microgrid current at the next sampling moment is predicted. By taking advantage of the engineering characteristic of the microgrid voltage being approximately stable, the second DC microgrid power is obtained by multiplying the DC microgrid voltage and the predicted second DC microgrid current. The entire process does not rely on empirical models or external feedback, which not only ensures the accuracy and reliability of power prediction, but also simplifies the calculation process, improves the response speed, and enhances the coordinated control accuracy of the DC microgrid and air conditioning equipment and the operational stability of the DC microgrid power supply system.

[0010] In one embodiment, the controller calculates the microgrid current change during the operation of the DC microgrid power supply system based on the voltage difference between the DC microgrid voltage and the bus voltage, and is configured as follows: The instantaneous rate of change of current in the DC microgrid power supply system is obtained by calculating the ratio of the voltage difference to the preset DC microgrid reactance in the DC microgrid power supply system. The product of the instantaneous rate of change of current and the preset sampling period is determined as the change in microgrid current.

[0011] In the above technical solution, the preset DC microgrid reactance, which reflects the inherent characteristics of the DC microgrid power supply system, is used as a benchmark. The instantaneous change rate of current is derived by the ratio of voltage difference to preset DC microgrid reactance. Then, the change in microgrid current is calculated by combining a fixed preset sampling period. The whole process does not rely on external feedback or complex models, which not only ensures the scientificity and accuracy of the current change calculation, but also simplifies the derivation process and improves the response speed.

[0012] In one embodiment, before the controller calculates the ratio of the voltage difference to the preset DC microgrid reactance in the DC microgrid power supply system to obtain the instantaneous rate of change of the current in the DC microgrid power supply system, it is further configured to: Obtain the predicted third DC microgrid current at the previous sampling time; the third DC microgrid current is predicted based on the change in microgrid current at the previous sampling time and the first DC microgrid current. The difference between the current of the first DC microgrid and the current of the third DC microgrid is calculated to obtain the current prediction deviation; If the current prediction deviation is greater than the preset current deviation, then the preset DC microgrid reactance is calibrated.

[0013] In the above technical solution, the predicted third DC microgrid current at the previous sampling time is introduced and compared with the current actual first DC microgrid current to obtain the current prediction deviation. When the current prediction deviation exceeds the preset threshold, the preset DC microgrid reactance is calibrated in a timely manner to effectively compensate for the dynamic offset of the DC microgrid reactance caused by component heating, topology changes, etc., correct the calculation errors of the instantaneous rate of change of current and the change of microgrid current, ensure the accuracy of the subsequent prediction of the second DC microgrid current and power, avoid the distortion of adjustment commands caused by the fixed value of reactance, and ensure the stability and reliability of the DC microgrid power supply system.

[0014] In one embodiment, the controller is configured to use the difference between the power of the first DC microgrid and the power of the second DC microgrid as the droop adjustment power: If the difference is positive, the difference is amplified based on the first adjustment coefficient to obtain the droop adjustment power; If the difference is negative, the difference is reduced based on the second adjustment coefficient to obtain the droop adjustment power.

[0015] In the above technical solution, when the difference is positive (the power of the DC microgrid power supply system will decrease), a first adjustment coefficient greater than 1 is used to amplify the difference. This strengthens the power reduction response of the air conditioning equipment to quickly match the decrease in microgrid power supply capacity and avoids widening the power gap. Conversely, when the difference is negative (the power of the DC microgrid power supply system will increase), a second adjustment coefficient between 0 and 1 is used to reduce the difference. This allows the air conditioning equipment to gradually increase its operating power to smoothly absorb excess energy, avoiding sudden current surges that could impact the microgrid. This approach balances targeted adjustment under different power change trends while ensuring voltage stability of the DC microgrid power supply system through amplitude control.

[0016] In one embodiment, after the controller uses the difference between the power of the first DC microgrid and the power of the second DC microgrid as the droop adjustment power and sends a control command containing the droop adjustment power to the air conditioning device, it is further configured to: Obtain the actual regulating power of the air conditioning equipment; Calculate the adjustment deviation between the actual adjustment power and the droop adjustment power; If the adjustment deviation is greater than the preset deviation threshold, the power adjustment step size of the air conditioning equipment will be adjusted; the power adjustment step size is used to describe the power amplitude when the air conditioning equipment adjusts its operating power in a single adjustment.

[0017] In the above technical solution, by obtaining the actual adjustment power (actual power adjustment range) after the air conditioning equipment responds to the control command, calculating the adjustment deviation between it and the droop adjustment power (target adjustment range), and dynamically adjusting the power adjustment step size (single adjustment range) of the air conditioning equipment when the adjustment deviation is greater than the preset deviation threshold, the problem of over-adjustment or under-adjustment caused by fixed power adjustment step size can be avoided, so that the air conditioning equipment can respond to the demand of droop adjustment power.

[0018] In one embodiment, the controller is further configured to: If the absolute value of the droop adjustment power is greater than the preset power threshold, then the preset sampling period between the current sampling time and the next sampling time is shortened. If the absolute value of the droop adjustment power is less than or equal to the preset power threshold, then the preset sampling period is maintained or extended.

[0019] In the above technical solution, the sampling period is dynamically adjusted by comparing the absolute value of the drooping adjustment power with a preset power threshold. When the absolute value of the drooping adjustment power is greater than the preset power threshold, it indicates a large power fluctuation. In this case, the preset sampling period is shortened to achieve high-frequency sampling and fast response, avoiding microgrid imbalance caused by adjustment lag. Conversely, when the absolute value of the drooping adjustment power is less than or equal to the preset power threshold, it indicates a smooth power fluctuation. In this case, maintaining or extending the preset sampling period can reduce the controller's computing power consumption and avoid operational oscillations caused by frequent fine-tuning of the air conditioner. This ensures both the timeliness and stability of adjustment when the microgrid power fluctuates significantly, and achieves system energy saving and stable operation when the fluctuation is smooth.

[0020] Secondly, a B-system method is provided, applied to the DC microgrid power supply system of the first aspect. The DC microgrid power supply system is connected to the air conditioning equipment via a DC bus, and the DC microgrid power supply system is used to supply power to the air conditioning equipment through the DC bus. The control methods for DC microgrid power supply systems include: When the air conditioning equipment is running, the DC bus voltage at the current sampling time is collected; Obtain the first DC microgrid current and DC microgrid voltage of the DC microgrid power supply system at the current sampling time; The power of the first DC microgrid power supply system is obtained by calculating the product of the first DC microgrid current and the DC microgrid voltage. Based on the voltage difference between the DC microgrid voltage and the bus voltage, the change in microgrid current during the operation of the DC microgrid power supply system is calculated. Based on the microgrid current change, the first DC microgrid current, and the DC microgrid voltage, predict the power of the second DC microgrid in the DC microgrid power supply system at the next sampling time. The difference between the power of the first DC microgrid and the power of the second DC microgrid is used as the droop adjustment power, and a control command containing the droop adjustment power is sent to the air conditioning equipment. The air conditioning equipment is configured to respond to control commands to adjust the operating power of the air conditioning equipment according to the droop adjustment power.

[0021] Thirdly, a computer-readable storage medium is provided, which stores a computer program that, when run by a DC microgrid power supply system, causes the DC microgrid power supply system to execute the control method of the DC microgrid power supply system in the second aspect.

[0022] Fourthly, a computer program product is provided, comprising: a computer program that, when run by a DC microgrid power supply system, causes the DC microgrid power supply system to execute the control method of the DC microgrid power supply system in the second aspect.

[0023] It is understood that the beneficial effects of the second to fourth aspects mentioned above can be found in the relevant descriptions in the first aspect mentioned above, and will not be repeated here. Attached Figure Description

[0024] Figure 1 This is a schematic diagram illustrating an application scenario between a DC microgrid power supply system and an air conditioning device, provided in one embodiment of this application. Figure 2 This is a timing interaction diagram of a control method for a DC microgrid power supply system according to an embodiment of this application; Figure 3 This is a schematic diagram illustrating one implementation of determining the power of a second DC microgrid in a control method for a DC microgrid power supply system provided in an embodiment of this application; Figure 4 This is a schematic diagram illustrating one implementation method for determining the microgrid current change in a control method for a DC microgrid power supply system provided in an embodiment of this application; Figure 5 This is a schematic diagram illustrating an implementation method for calibrating the preset DC microgrid reactance in a control method for a DC microgrid power supply system provided in an embodiment of this application; Figure 6 This is a schematic diagram illustrating one implementation method of adjusting the power regulation step size in a control method for a DC microgrid power supply system provided in an embodiment of this application; Figure 7 This is a schematic diagram illustrating one implementation method of adjusting the preset sampling period in a control method for a DC microgrid power supply system provided in an embodiment of this application. Detailed Implementation

[0025] The technical solutions of the embodiments of this application will be described below with reference to the accompanying drawings. In the description of the embodiments of this application, unless otherwise stated, " / " means "or," for example, A / B can mean A or B; "and / or" in this text is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Furthermore, in the description of the embodiments of this application, "multiple" refers to two or more than two.

[0026] Hereinafter, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first," "second," or "third" may explicitly or implicitly include one or more of that feature.

[0027] Specific details, such as particular system architectures and techniques, are set forth for illustrative purposes and not for limitation, to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted to avoid unnecessary detail that could obscure the description of this application.

[0028] In some related technologies, with the rapid development of distributed new energy sources (such as photovoltaics and energy storage), DC microgrids are widely used in building power supply and remote area power supply scenarios due to their advantages such as not requiring frequent AC-DC conversion, high energy transmission efficiency, and adaptability to distributed power sources and DC load characteristics. Air conditioning equipment, as a high-power load, directly affects the power balance and voltage stability of the DC microgrid due to fluctuations in its operating power. The mode of supplying power to air conditioning equipment through a DC bus has become one of the mainstream architectures of new energy power supply systems, and its operational reliability directly determines the user's power experience and energy utilization efficiency.

[0029] For example, refer to Figure 1 , Figure 1 This is a schematic diagram illustrating an application scenario between a DC microgrid power supply system and an air conditioning unit, according to an embodiment of this application. The DC microgrid power supply system can be connected to the air conditioning unit via a DC bus connection to provide power for the air conditioning unit's operation.

[0030] It should be noted that a DC microgrid power supply system can power multiple air conditioning devices simultaneously, or it can function as a single air conditioning device; there is no limitation on this.

[0031] The aforementioned air conditioning equipment refers to electrical equipment used to regulate indoor environmental parameters such as temperature and humidity. In this embodiment, the air conditioning equipment is an air conditioner that can operate on direct current (or an air conditioner that operates in direct current mode after internal circuit conversion). Generally, air conditioning equipment may include, but is not limited to, components such as compressors and motors.

[0032] The aforementioned DC microgrid power supply system is a system that converts clean energy (e.g., solar and wind energy) into direct current (DC) to provide power to loads (such as air conditioning equipment). For example, taking a photovoltaic (PV) power generation system as an example, a PV power generation system typically includes PV modules (solar panels), a combiner box, and a DC controller. The PV modules are made of semiconductor materials (such as silicon) and can directly convert sunlight into DC. The combiner box aggregates the DC power generated by multiple PV modules, reducing line losses and centralizing the output. The DC controller processes the DC power output from the PV modules (e.g., stabilizing voltage, preventing overcharging / over-discharging) to ensure that the output DC power meets the power requirements of the load (air conditioning equipment) (e.g., the voltage is stable within the acceptable range for the air conditioner).

[0033] Based on the above explanation of photovoltaic power generation systems, it can be seen that photovoltaic power generation has significant power supply fluctuations. Affected by factors such as light intensity (e.g., cloud cover, day and night alternation) and ambient temperature, its output power will change frequently and rapidly (for example, when a sunny day is suddenly hit by a cloud shadow, the photovoltaic power supply may drop by 30% to 50% within a few seconds).

[0034] Currently, when a sudden drop in power supply to a DC microgrid causes an initial dip in the DC bus voltage, energy storage devices can quickly intervene to replenish the load's energy consumption. However, in practical applications of DC microgrids, considering cost and safety factors, the energy stored in energy storage devices is usually limited, or energy storage devices are not installed due to cost constraints.

[0035] At this time, in related technologies, the adaptation control of air conditioning equipment and DC microgrids mostly adopts the mode of load-side voltage feedback and constant power regulation. For example, the air conditioning equipment, as the load end, detects the bus voltage of the DC bus in real time, and adapts to the power fluctuations of the DC microgrid through its own constant power operation characteristics, thereby maintaining the stability of the DC microgrid operation.

[0036] The constant power characteristic forces the air conditioning equipment to increase its current demand in the opposite direction (to maintain power stability). Specifically, when the DC microgrid experiences a voltage drop due to reduced renewable energy output or a sudden increase in other loads, the air conditioning equipment will increase its current demand to offset the voltage drop in order to maintain stable operating power (according to the power formula P=U×I). Conversely, when the DC microgrid experiences a voltage rise due to a sudden increase in renewable energy output or a sudden decrease in other loads, the air conditioning equipment will reduce its current demand to avoid exceeding its rated power and attempt to adapt to the microgrid's power surplus state, thereby achieving initial coordination between itself and the microgrid.

[0037] However, increased current will further aggravate line losses and voltage drops, forming a vicious cycle of voltage decrease → current increase → voltage further decrease, which may eventually lead to voltage collapse of the DC microgrid, triggering the shutdown of air conditioning equipment or even damaging power electronic devices.

[0038] Therefore, in order to maintain the operational stability of the DC microgrid power supply system, this application provides a DC microgrid power supply system, wherein the DC microgrid power supply system is connected to the air conditioning equipment via a DC bus, and the DC microgrid power supply system is used to supply power to the air conditioning equipment through the DC bus. The DC microgrid power supply system includes: a voltage sampler, configured to: collect the bus voltage of the DC bus at the current sampling time when the air conditioning equipment is running.

[0039] In one embodiment, the aforementioned bus voltage can be considered as the instantaneous voltage sampled by the voltage sampler from the DC bus. The voltage sampler is physically connected to the DC bus via dedicated circuitry (such as a voltage divider resistor network or a filter circuit) to monitor the voltage on the DC bus in real time. When the voltage sampler triggers sampling logic (such as timed sampling or a sampling command initiated by the controller), it can capture the analog voltage signal of the DC bus (e.g., the analog electrical signal corresponding to 352.3V) at a certain moment (denoted as t1). Subsequently, the voltage sampler or controller can convert the acquired analog voltage signal into a digital signal recognizable by the controller using its internally integrated ADC (analog-to-digital converter) to obtain the aforementioned bus voltage.

[0040] Please see Figure 2 , Figure 2 This is a timing interaction diagram of a control method for a DC microgrid power supply system according to an embodiment of this application, as shown below. Figure 2 As shown, the controller is configured to perform the following steps: S201. Obtain the first DC microgrid current and DC microgrid voltage of the DC microgrid power supply system at the current sampling time.

[0041] In one embodiment, the aforementioned current sampling time is a specific time node at which the controller triggers parameter collection according to a preset sampling period (e.g., milliseconds). It serves as the time reference for the DC microgrid power supply system to carry out real-time control. It is connected with the previous sampling time and the next sampling time to ensure the timing synchronization of power prediction and adjustment, which meets the real-time requirements of DC microgrid dynamic control.

[0042] The aforementioned first DC microgrid current is the total current flowing through the main circuit of the DC microgrid at the current sampling time. It is a direct reflection of the power transmission intensity of the microgrid. Its value comprehensively reflects the current balance state of the microgrid power output and load consumption at the current moment. The term "first" is used to distinguish the subsequent second and third DC microgrid currents obtained based on prediction.

[0043] The aforementioned DC microgrid voltage is the total voltage at the input terminal or main line of the DC microgrid at the current sampling time. It is the reference voltage for microgrid power supply, distinct from the first bus voltage, and directly determines the power transmission capacity of the DC microgrid power supply system.

[0044] The controller actively acquires the aforementioned parameters using current and voltage sensors deployed on the main circuit of the DC microgrid. The current sensor can be connected in series on the main line of the DC microgrid power supply system to detect the first DC microgrid current flowing through the line in real time; the voltage sensor is connected in parallel across the main line to acquire the first DC microgrid voltage in real time; the acquisition actions of the two types of sensors are triggered synchronously with the preset sampling period, and the acquired electrical signals are transmitted to the controller after analog-to-digital conversion to achieve real-time parameter acquisition.

[0045] S202. Calculate the product of the first DC microgrid current and the DC microgrid voltage to obtain the first DC microgrid power of the DC microgrid power supply system.

[0046] In one embodiment, the first DC microgrid power is the total power output of the DC microgrid power supply system at the current sampling time. It is a relatively important quantitative indicator of the current power supply capacity of the DC microgrid power supply system. The first DC microgrid power is obtained by multiplying the first DC microgrid current and the DC microgrid voltage.

[0047] Understandably, the first DC microgrid power is obtained by multiplying the two, without relying on external equipment feedback. The calculation logic is simple and the response is fast, which can ensure the accuracy of the current power data.

[0048] S203. Based on the voltage difference between the DC microgrid voltage and the bus voltage, calculate the change in microgrid current during the operation of the DC microgrid power supply system.

[0049] In one embodiment, the voltage difference is the difference between the DC microgrid voltage and the bus voltage at the current sampling time, and its physical essence is the voltage drop across the DC microgrid reactance. The portion of the DC microgrid voltage used to overcome the reactance's resistance to current changes directly reflects the current dynamic load state and power transmission characteristics of the DC microgrid power supply system, and can serve as a basis for deducing current change trends.

[0050] The aforementioned microgrid current change can be considered as the expected change in the total current in the DC microgrid power supply system within a preset sampling period. The positive or negative sign of the microgrid current change corresponds to the direction of current increase or decrease (positive value indicates current increase, negative value indicates current decrease).

[0051] As an example, the controller can calculate the ratio of the voltage difference to a preset resistance to obtain the current difference. Then, the ratio of the current difference to a preset sampling period is determined as the expected change amplitude. Alternatively, the voltage difference and the line information (e.g., resistance) of the DC microgrid power supply system can be input into a preset current change prediction model to obtain the aforementioned microgrid current change. In this embodiment, the method for determining the microgrid current change is not limited.

[0052] S204. Based on the microgrid current change, the first DC microgrid current, and the DC microgrid voltage, predict the power of the second DC microgrid in the DC microgrid power supply system at the next sampling time.

[0053] In one embodiment, the next sampling time refers to the time node after the current sampling time, which triggers the next parameter acquisition according to a preset sampling period. It is connected before and after the current sampling time and is the target timing node for predicting changes in the microgrid status, ensuring that power prediction is synchronized with the actual operating sequence.

[0054] The aforementioned second DC microgrid power is the expected total output power of the DC microgrid power supply system at the next sampling time, derived from the parameters at the current sampling time. It forms a time sequence distinction with the first DC microgrid power at the current sampling time and is a relatively important indicator for predicting the trend of microgrid power change.

[0055] As an example, the controller can predict the power of the second DC microgrid based on a preset DC microgrid power prediction model. For instance, the DC microgrid power prediction model can be trained in advance using microgrid current changes, the first DC microgrid current, the DC microgrid voltage, and the actual DC microgrid current as training samples.

[0056] S205. The difference between the power of the first DC microgrid and the power of the second DC microgrid is used as the droop adjustment power, and a control command containing the droop adjustment power is sent to the air conditioning equipment.

[0057] The air conditioning equipment is configured to respond to control commands to adjust the operating power of the air conditioning equipment according to the droop adjustment power.

[0058] In one embodiment, the aforementioned droop adjustment power is the difference between the first DC microgrid power at the current sampling time and the second DC microgrid power at the next sampling time. Its magnitude reflects the expected change in microgrid power, with positive and negative values ​​corresponding to the direction of power change. Typically, a positive value indicates that the DC microgrid power will decrease, and a negative value indicates that the DC microgrid power will increase.

[0059] It should be noted that the aforementioned droop adjustment power is a precise adjustment power customized for air conditioning equipment to address future power fluctuations in the DC microgrid power supply system.

[0060] The aforementioned control commands refer to digital commands (such as pulse signals, communication protocol frames, etc.) generated by the controller that contain droop adjustment power parameters. The control commands clearly specify the power amplitude and direction that the air conditioning equipment needs to adjust, eliminating the need for the air conditioning equipment to make its own judgment; it only needs to execute the commands to complete the adaptation.

[0061] The aforementioned operating power refers to the total power actually consumed by the air conditioning equipment under the current operating conditions. It is the sum of the power of components such as the air conditioning compressor and fan during operation, and directly determines the load demand of the air conditioning equipment on the DC microgrid. Its size needs to be dynamically adapted to the power supply capacity of the microgrid to ensure the power balance of the microgrid and the operating effect of the air conditioning.

[0062] As an example, an air conditioning unit can adjust the compressor speed to regulate its operating power. For instance, if the droop adjustment power is positive (corresponding to a decrease in the power of the first DC microgrid), the air conditioning unit needs to reduce its operating power to alleviate the microgrid's power supply pressure. In this case, the air conditioning unit can reduce the compressor's operating speed according to the magnitude of the droop adjustment power. After the speed decreases, the compressor's efficiency in compressing the refrigerant decreases, the cooling / heating power decreases simultaneously, and the overall operating power of the air conditioning unit decreases accordingly. This also reduces the current demand on the microgrid, adapting to the future power reduction trend of the microgrid.

[0063] Furthermore, if the droop adjustment power is negative (corresponding to an increase in the power of the first microgrid), the air conditioning equipment needs to increase its operating power to absorb the excess power of the microgrid. In this case, the air conditioner can increase the compressor's operating speed based on the absolute value of the droop adjustment power. After the speed increases, the compressor's efficiency improves, the cooling / heating power increases simultaneously, and the overall operating power of the air conditioning equipment increases accordingly. At the same time, it increases the current demand on the microgrid, adapting to the future power increase trend of the microgrid.

[0064] In another embodiment, the air conditioning equipment can also synchronously adjust the fan speed to match the operating power of the compressor.

[0065] It should be noted that the controller calculates the droop adjustment power by subtracting the first DC microgrid power (the actual power at the current sampling time) and the second DC microgrid power (the predicted power at the future sampling time) obtained in the previous steps. This allows for the quantification of the compensation range required for future power fluctuations in the DC microgrid power supply system. The droop adjustment power is then encapsulated into standardized control commands and sent to the air conditioning equipment via wired or wireless communication links. The entire process can be completed without the air conditioning equipment participating in data calculation or decision-making; it only needs to passively respond to control commands. This avoids the inherent delay of autonomous decision-making by the air conditioning equipment and, through the design of control commands based on predicted future power changes, allows the air conditioning equipment to know in advance the required power adjustment range, reserving time for subsequent power adaptation and overcoming the lag problem of adjusting only after voltage changes in related technologies.

[0066] In this embodiment, the DC bus voltage at the current sampling moment is collected by a voltage sampler. Combined with the current DC microgrid current and DC microgrid voltage obtained by the controller, the power of the first DC microgrid is calculated based on the power formula, providing accurate basic data support for subsequent control. Then, the change in microgrid current is calculated based on the voltage difference between the DC microgrid voltage and the bus voltage, ensuring that the calculated result reflects the dynamic trend of the microgrid current over a short period. That is, the predicted current at the next sampling moment can be directly predicted using the current first DC microgrid current and the microgrid current change describing the trend of microgrid current change. Furthermore, by using an approximately constant DC microgrid voltage and predicted current, the power of the second DC microgrid at the next sampling moment can be accurately predicted, overcoming the limitation of only being able to make post-event adjustments based on current measured parameters and achieving advance prediction of the microgrid power change trend. Then, the difference between the first and second DC microgrid power is used as the droop adjustment power, so that the adjustment signal directly corresponds to the power change demand of the microgrid, ensuring the pertinence and accuracy of the control command and avoiding system oscillations caused by blind adjustment. Finally, the air conditioning equipment responds to the control command and adjusts its operating power, enabling it to adapt to the power supply and demand status of the microgrid in advance. This mitigates the risk of power imbalance caused by power fluctuations and sudden load changes in the DC microgrid power supply system, improving the power balance capability and operational stability of the DC microgrid. Furthermore, this control method is executed by the DC microgrid power supply system, eliminating the need for the air conditioning equipment to perform data detection, deviation calculation, and decision-making autonomously. It only needs to respond to the control command to adjust its operating power, shifting the control node from passively remedying power imbalances after they occur to proactively predicting power changes before they happen. This significantly reduces the inherent delay in autonomous detection and decision-making at the air conditioning equipment end, allowing it to complete adaptive adjustments before the actual occurrence of microgrid power imbalances, ensuring the operational stability of the DC microgrid and the continuity of air conditioning equipment operation.

[0067] In another embodiment, the controller can be based on, for example... Figure 3The steps S301-S302 shown predict the power of the second DC microgrid described above. Details are as follows: S301. Sum the change in microgrid current with the first DC microgrid current to predict the second DC microgrid current at the next sampling time.

[0068] S302. The product of the DC microgrid voltage and the second DC microgrid current is determined as the power of the second DC microgrid.

[0069] In one embodiment, the second DC microgrid current refers to the current flowing through the DC microgrid power supply system at the next sampling time, which is predicted based on the data at the current sampling time. It is the sum of the first DC microgrid current and the change in microgrid current.

[0070] It should be noted that since the preset sampling period of the DC microgrid power supply system is on the order of milliseconds, the DC microgrid voltage fluctuation is extremely small within a short period of time and can be approximated as stable. Therefore, there is no need to additionally predict the DC microgrid voltage at the next sampling moment. Thus, the DC microgrid voltage at the current sampling moment can be reused for calculation, which will not affect the prediction accuracy, but also simplifies the calculation process and improves the response speed, meeting the practical engineering requirements of microgrid dynamic control.

[0071] In this embodiment, based on the actual first DC microgrid current and the change in microgrid current at the current sampling moment, the second DC microgrid current at the next sampling moment is predicted. By taking advantage of the engineering characteristic that the microgrid voltage is approximately stable, the second DC microgrid power is obtained by multiplying the DC microgrid voltage and the predicted second DC microgrid current. The entire process does not rely on empirical models or external feedback, which not only ensures the accuracy and reliability of power prediction, but also simplifies the calculation process, improves the response speed, and enhances the coordinated control accuracy of the DC microgrid and air conditioning equipment and the operational stability of the DC microgrid power supply system.

[0072] In another embodiment, the controller can be based on, for example... Figure 4 The steps S401-S402 shown are for calculating the microgrid current change. Details are as follows: S401. Calculate the ratio of the voltage difference to the preset DC microgrid reactance in the DC microgrid power supply system to obtain the instantaneous rate of change of current in the DC microgrid power supply system.

[0073] S402. The product of the instantaneous rate of change of current and the preset sampling period is determined as the change in microgrid current.

[0074] In one embodiment, the aforementioned preset DC microgrid reactance refers to the equivalent inductance value preset based on the inherent hardware attributes of the DC microgrid power supply system during the design or startup phase of the DC microgrid power supply system. This includes, but is not limited to, the distributed inductance of the DC microgrid power supply system and the inductance of components such as DC / DC converters and energy storage devices. It is a basic circuit parameter reflecting the characteristics of the DC microgrid power supply system in impeding current changes and serves as an initial reference value for deriving the current change trend.

[0075] The instantaneous rate of change of current mentioned above refers to the speed at which the DC microgrid current changes with time at a certain moment. Its magnitude reflects how fast the current changes, and positive and negative values ​​correspond to the direction of current increase or decrease (positive values ​​indicate that the current is accelerating and increasing, and negative values ​​indicate that the current is accelerating and decreasing). It is the physical bridge connecting the voltage difference and the change in microgrid current, and determines the magnitude of the current change at the next sampling moment.

[0076] It should be noted that the DC microgrid voltage is the load-side voltage (the voltage supplied to the DC bus) and the voltage used to overcome the resistance of the reactance in the DC bus to current changes. Therefore, by calculating the voltage difference between the DC microgrid voltage and the bus voltage, and then comparing this voltage difference with the preset DC microgrid reactance, the instantaneous rate of change of current is finally obtained. The entire calculation process strictly follows physical laws to ensure that the results can truly reflect the dynamic trend of the microgrid current.

[0077] In this embodiment, the preset DC microgrid reactance, which reflects the inherent characteristics of the DC microgrid power supply system, is used as a benchmark. The instantaneous rate of change of current is derived by the ratio of voltage difference to preset DC microgrid reactance. Then, the change of microgrid current is calculated by combining a fixed preset sampling period. The whole process does not rely on external feedback or complex models, which not only ensures the scientificity and accuracy of the current change calculation, but also simplifies the derivation process and improves the response speed.

[0078] In another embodiment, the DC microgrid reactance in the DC microgrid power supply system is not a fixed physical quantity; its value changes dynamically with the operating conditions of the DC microgrid power supply system. Specifically, the inductance of components such as the DC / DC converter and energy storage battery in the DC microgrid power supply system will experience slight shifts due to heat generation during long-term operation and fluctuations in switching frequency. Furthermore, the connection or removal of microgrid loads (such as the start-up and shutdown of other electrical equipment) and fluctuations in distributed power output (such as changes in photovoltaic power) will alter the equivalent topology of the main circuit, thereby causing changes in the distributed inductance of the lines and the overall equivalent reactance. Therefore, using a fixed preset DC microgrid reactance to calculate the microgrid current change has low accuracy.

[0079] Therefore, in order to improve the accuracy of microgrid current changes, the controller can, based on, such as Figure 5 The steps S501-S503 shown are for calibrating the preset DC microgrid reactance. Details are as follows: S501. Obtain the predicted third DC microgrid current at the previous sampling time.

[0080] The third DC microgrid current is predicted based on the change in microgrid current at the previous sampling time and the first DC microgrid current.

[0081] In one embodiment, the previous sampling time refers to a specific time node before the current sampling time, which triggers parameter acquisition and prediction according to a preset sampling period (the interval between the current sampling time and the next sampling time is fixed). It is the preceding node of the current sampling time in the time sequence chain, and is connected to the current sampling time to provide historical prediction data support for parameter calibration at the current time.

[0082] The aforementioned third DC microgrid current refers to the microgrid current that should appear at the current sampling time, predicted by summing the first DC microgrid current (the actual current at the previous sampling time) and the change in microgrid current (the expected change in current derived from the previous sampling time). The term "third" distinguishes the actual current at the current sampling time (the first DC microgrid current) from the predicted DC microgrid current pointing towards the future (the second DC microgrid current). It can be compared with the actual current at the current sampling time (the first DC microgrid current) to identify current prediction deviations.

[0083] It is understandable that, based on the steps S401-S402 above, the prediction of the second DC microgrid current needs to be based on the DC microgrid reactance. Therefore, the predicted current deviation can be used as the basis for whether to calibrate the preset DC microgrid reactance.

[0084] The method for predicting the third DC microgrid current is the same as that for predicting the second DC microgrid current, and will not be explained further. It is important to note that when predicting the third DC microgrid current, the first DC microgrid current at the previous sampling time (the actual current at that time) and the change in microgrid current at the previous sampling time (the derived current change amplitude at that time) are used. When predicting the second DC microgrid current, the first DC microgrid current at the current sampling time (the current actual current) and the change in microgrid current at the current sampling time (the currently derived current change amplitude) are used. Both are based on the same physical laws and prediction logic; the only difference is the timing, with the base current and current change parameters used at the corresponding time points, ensuring the consistency and rigor of the entire prediction system.

[0085] S502. Calculate the difference between the current of the first DC microgrid and the current of the third DC microgrid to obtain the current prediction deviation.

[0086] S503. If the current prediction deviation is greater than the preset current deviation, then calibrate the preset DC microgrid reactance.

[0087] In one embodiment, the aforementioned current prediction deviation is the difference between the first DC microgrid current at the current sampling time and the third DC microgrid current predicted at the previous sampling time. The magnitude of this current prediction deviation reflects the accuracy of the previous prediction, with positive and negative values ​​corresponding to the direction of deviation. A positive value indicates that the actual first DC microgrid current is greater than the predicted third DC microgrid current, while a negative value indicates that the actual first DC microgrid current is less than the predicted third DC microgrid current. This is a quantitative indicator for determining whether the preset DC microgrid reactance deviates from the true value.

[0088] The aforementioned preset current deviation is a pre-set maximum allowable current prediction error threshold, which serves as the criterion for triggering reactance calibration. This avoids fluctuations in the DC microgrid power supply system caused by frequent calibrations due to minor errors, while also promptly correcting larger deviations to ensure prediction accuracy.

[0089] The calibration method can be to adjust the above difference using a preset coefficient. This preset coefficient can be set in advance and is not limited in its specific application.

[0090] As an example, if the difference is positive, the difference is amplified based on the first adjustment coefficient to obtain the droop adjustment power. If the difference is negative, the difference is reduced based on the second adjustment coefficient to obtain the droop adjustment power.

[0091] In one embodiment, the first adjustment coefficient is a preset fixed coefficient greater than 1 (e.g., 1.2-1.5), which is used only when the difference between the power of the first DC microgrid and the power of the second DC microgrid is positive, in order to amplify the droop adjustment power and make the final droop adjustment power more effective.

[0092] Furthermore, the second adjustment coefficient is a preset fixed coefficient between 0 and 1 (e.g., 0.6-0.9), which is only used when the power difference is negative, in order to reduce the droop adjustment power and make the final droop adjustment power smoother.

[0093] It should be noted that a positive difference indicates a decrease in power supply capacity at the next sampling time. At this time, the demand of the air conditioning equipment is to quickly reduce power consumption to keep up with the pace of power supply capacity reduction. For example, if the power supply of the DC microgrid system needs to be reduced by 100W, and the air conditioning equipment only reduces by 80W, there will be a 20W shortfall causing a voltage drop. However, if the air conditioning equipment reduces by 120W, it can quickly match the power supply reduction to meet the demand, and even reserve a small amount of redundancy, thus preventing the shortfall from expanding at the source.

[0094] Furthermore, a negative difference indicates an increase in the power of the DC microgrid power supply system. If the air conditioning equipment rapidly and significantly increases its power, it will cause a sudden increase in the current of the DC microgrid power supply system, leading to voltage fluctuations. In this case, the increased power of the DC microgrid power supply system is excess power, and the main task of the air conditioning equipment is to smoothly absorb the excess energy, rather than instantly consuming all the excess power. Therefore, reducing the adjustment range allows the air conditioning unit's operating power to gradually increase, absorbing excess energy while avoiding the impact of sudden current surges on the microgrid, and ensuring the stable operation of components such as the air conditioning compressor, thus extending their lifespan.

[0095] In this embodiment, when the difference is positive (the power of the DC microgrid power supply system will decrease), a first adjustment coefficient greater than 1 is used to amplify the difference. This strengthens the power reduction response of the air conditioning equipment to quickly match the decrease in microgrid power supply capacity and prevent the power gap from widening. Conversely, when the difference is negative (the power of the DC microgrid power supply system will increase), a second adjustment coefficient between 0 and 1 is used to reduce the difference. This allows the air conditioning equipment to gradually increase its operating power to smoothly absorb excess energy, preventing sudden current surges from impacting the microgrid. This approach balances targeted adjustment under different power change trends while ensuring voltage stability of the DC microgrid power supply system through amplitude control.

[0096] In another embodiment, when the current prediction deviation is less than or equal to the preset current deviation, the predicted third DC microgrid current at the previous sampling time can be considered accurate, meaning the preset DC microgrid reactance has high accuracy. Therefore, calibration of the preset DC microgrid reactance is unnecessary.

[0097] In this embodiment, the predicted third DC microgrid current at the previous sampling time is introduced and compared with the current actual first DC microgrid current to obtain the current prediction deviation. When the current prediction deviation exceeds the preset threshold, the preset DC microgrid reactance is calibrated in a timely manner to effectively compensate for the dynamic offset of the DC microgrid reactance caused by component heating, topology changes, etc., correct the calculation errors of the instantaneous rate of change of current and the amount of change of microgrid current, ensure the accuracy of the subsequent prediction of the second DC microgrid current and power, avoid the distortion of adjustment commands caused by the fixed value of reactance, and ensure the stability and reliability of the DC microgrid power supply system.

[0098] It should be noted that when air conditioning equipment adjusts its operating power in response to control commands, the compressor speed cannot change abruptly without regulation; it typically needs to be adjusted gradually in fixed increments. Therefore, if the power adjustment step size is not dynamically adjusted, when the power fluctuation of the DC microgrid power supply system is small, a fixed, large step size will cause the air conditioning equipment to adjust too much in a single instance, resulting in the actual adjusted power exceeding or falling below the droop adjustment power, creating a continuous deviation. When the power fluctuation of the DC microgrid power supply system is large, a fixed, small step size will cause the adjustment speed to lag behind the fluctuation rhythm, leading to an imbalance between power supply and demand in the DC microgrid power supply system and causing continuous fluctuations in the bus voltage.

[0099] Therefore, in order to ensure the stable operation of the DC microgrid power supply system, the controller can, according to, such as Figure 6 The steps S601-S603 shown indicate how to adjust the operating power of the air conditioning equipment. Details are as follows: S601. Obtain the actual regulating power of the air conditioning equipment.

[0100] S602. Calculate the adjustment deviation between the actual adjustment power and the droop adjustment power.

[0101] In one embodiment, the aforementioned actual adjustment power refers to the actual adjustment range of the operating power of the air conditioning equipment after responding to the control command. It only reflects the amount of power change, not the final operating power after adjustment. For example, if the original operating power of the air conditioning equipment is 500W, and it receives a command to adjust the power by -100W (power reduction is required), it will actually reduce the power to 420W. At this time, the actual adjustment power is 80W (i.e., the actual adjustment range), reflecting the air conditioning equipment's execution of the control command and the actual change range.

[0102] The aforementioned adjustment deviation refers to the difference between the actual adjustment power of the air conditioning equipment (the actual adjustment range after responding to the command) and the droop adjustment power (the target adjustment range required by the command). The magnitude of the value reflects the degree to which the air conditioning equipment executes the control command and matches the target requirements, with positive and negative values ​​corresponding to the direction of deviation. For example, a positive value indicates that the actual adjustment power is greater than the droop adjustment power, while a negative value indicates that the actual adjustment power is less than the droop adjustment power. This serves as an indicator for determining whether the power adjustment step size needs to be adjusted.

[0103] S603. If the adjustment deviation is greater than the preset deviation threshold, adjust the power adjustment step size of the air conditioning equipment.

[0104] Among them, the power adjustment step size is used to describe the power range when the air conditioning equipment adjusts its operating power in a single operation.

[0105] In one embodiment, the aforementioned preset deviation threshold can be a preset allowable adjustment error value based on the operational stability of the DC microgrid power supply system and the adjustment accuracy requirements of the air conditioning equipment.

[0106] The aforementioned power adjustment step size is a fixed range when the air conditioning equipment adjusts its operating power in a single cycle. It determines the magnitude of each power change in the air conditioning equipment and serves as a rhythmic parameter for controlling the air conditioning equipment to approach the target adjustment range (droop adjustment power). The larger the power adjustment step size, the stronger the adjustment force in a single cycle; the smaller the power adjustment step size, the gentler the adjustment force in a single cycle.

[0107] In one embodiment, if the adjustment deviation exceeds a preset deviation threshold, it indicates that the current power adjustment step size is insufficient to meet the requirements for precise adjustment. In this case, if the power adjustment step size is too large, the adjustment range corresponding to the actual adjusted power may be greater than the droop adjustment power. Alternatively, if the power adjustment step size is too small, the adjustment range corresponding to the actual adjusted power may be insufficient, requiring multiple adjustments to the operating power.

[0108] Therefore, when the power adjustment step size is too small, increasing the step size can enhance the adjustment force per adjustment, allowing the actual adjusted power to quickly approach the droop adjustment power. Conversely, when the power adjustment step size is too large, appropriately decreasing the step size reduces the adjustment force per adjustment, preventing over-adjustment. This ensures that the actual adjusted power of the air conditioning equipment matches the droop adjustment power, balancing adjustment efficiency and system operational stability.

[0109] In one embodiment, the adjustment method of the power adjustment step size is not limited to proportional adjustment and step adjustment, and there is no limitation thereto.

[0110] In another embodiment, if the adjustment deviation is less than or equal to a preset deviation threshold, it indicates that the power adjustment step size meets the requirements, and thus, there is no need to adjust the power adjustment step size of the air conditioning equipment.

[0111] In this embodiment, by obtaining the actual adjustment power (actual power adjustment range) after the air conditioning equipment responds to the control command, the adjustment deviation between the actual power adjustment and the target adjustment range is calculated. When the adjustment deviation is greater than the preset deviation threshold, the power adjustment step size (single adjustment range) of the air conditioning equipment is dynamically adjusted until the preset deviation threshold is met. This can avoid the problem of over-adjustment or under-adjustment caused by a fixed power adjustment step size, and enable the air conditioning equipment to respond to the demand for droop adjustment power.

[0112] In another embodiment, it should be noted that the power of a DC microgrid power supply system is easily affected by distributed power output (such as photovoltaic and wind power) and load changes, exhibiting two typical scenarios: large fluctuations and gradual fluctuations. In related technologies, the preset sampling period is often a fixed value. If the preset sampling period is too short, the DC microgrid power supply system will frequently collect and calculate data, increasing the controller's computing power loss, and excessively frequent adjustments may cause oscillations in the air conditioning equipment. If the preset sampling period is too long, it will be unable to capture the power change trend in a timely manner when facing large power fluctuations in the DC microgrid power supply system, resulting in delayed control commands, and consequently causing microgrid power imbalance and bus voltage fluctuations.

[0113] Therefore, in order to perform sampling calculations reasonably, the controller can, according to, such as Figure 7 The steps S701-S702 shown determine the preset sampling period. Details are as follows: S701. If the absolute value of the droop adjustment power is greater than the preset power threshold, then shorten the preset sampling period between the current sampling time and the next sampling time.

[0114] In one embodiment, the aforementioned preset power threshold is a critical value used to determine the power fluctuation amplitude of the microgrid, and a standard used to distinguish between large power fluctuations and smooth fluctuations in the microgrid power.

[0115] The methods for shortening the preset sampling period mentioned above include, but are not limited to, fixed shortening and proportional shortening. For example, fixed shortening directly reduces the current sampling period to a preset short period. And proportional shortening compresses the period by a fixed proportion.

[0116] It should be noted that when the drooping power exceeds the preset power threshold, it indicates that the microgrid power is about to experience significant fluctuations (such as a sudden increase or decrease in distributed power output). In this case, the preset sampling period between the current and next sampling moments needs to be shortened. By using a more frequent sampling frequency, details of power changes can be quickly captured, and calculations and control commands can be updated and adjusted in a timely manner. This avoids adjustment lag caused by excessively long sampling intervals, ensuring that the air conditioning equipment can quickly adapt to significant fluctuations in microgrid power and guaranteeing the microgrid's supply-demand balance and voltage stability.

[0117] S702. If the absolute value of the droop adjustment power is less than or equal to the preset power threshold, then maintain or extend the preset sampling period.

[0118] In one embodiment, the above-mentioned method of extending the preset sampling period can be a fixed extension method, which directly adjusts the preset sampling period to a preset long period. For example, the original preset sampling period of 50ms is extended to 100ms. Alternatively, it can be a step-by-step extension method, which gradually extends the period according to a fixed gradient. For example, it is extended by 20ms each time until the maximum allowable period is reached.

[0119] It should be noted that when the droop adjustment power is less than or equal to the preset power threshold, it indicates that the microgrid power fluctuation is smooth and does not require high-frequency sampling and adjustment. In this case, maintaining the original preset sampling period or extending it appropriately can reduce the frequency of data collection and calculation by the controller, reduce computing power consumption, and avoid frequent fine-tuning of the air conditioning equipment due to excessive sampling, thereby reducing the oscillation of the air conditioning equipment during operation.

[0120] It is understandable that at this time, the time difference between the next sampling time and the current sampling time is the preset sampling period corresponding to the above steps S701-S702.

[0121] In this embodiment, the sampling period is dynamically adjusted by comparing the absolute value of the drooping adjustment power with a preset power threshold. When the absolute value of the drooping adjustment power is greater than the preset power threshold, it indicates a large power fluctuation. In this case, the preset sampling period is shortened to achieve high-frequency sampling and fast response, avoiding microgrid imbalance caused by adjustment lag. Conversely, when the absolute value of the drooping adjustment power is less than or equal to the preset power threshold, it indicates a smooth power fluctuation. In this case, maintaining or extending the preset sampling period can reduce the controller's computing power consumption and avoid operational oscillations caused by frequent fine-tuning of the air conditioner. This ensures both the timeliness and stability of adjustment when the microgrid power fluctuates significantly, and achieves system energy saving and stable operation when the power fluctuates smoothly.

[0122] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0123] In another embodiment, such as Figure 2 As shown, the DC microgrid power supply system can be used to implement the control method of the DC microgrid power supply system described in the above method embodiments.

[0124] A DC microgrid power supply system may include one or more memories storing programs that can be run by a controller to generate instructions, causing the controller to execute the control method of the DC microgrid power supply system described in the above method embodiments according to the instructions.

[0125] Optionally, the memory may also store data. Optionally, the controller may also read data stored in the memory, which may be stored at the same memory address as the program, or the data may be stored at a different memory address than the program.

[0126] The controller and memory can be set up separately or integrated together; for example, integrated on the system on chip (SOC) of the terminal device.

[0127] This application also provides a computer program product that, when executed by a controller, implements the control method of the DC microgrid power supply system of any method embodiment in this application.

[0128] The computer program product can be stored in memory, for example, as a program. The program is eventually converted into an executable object file that can be executed by the controller after processes such as preprocessing, compilation, assembly, and linking.

[0129] This application also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a computer, implements the control method of the DC microgrid power supply system in any embodiment of the method in this application. The computer program may be a high-level language program or an executable object program.

[0130] The computer-readable storage medium is, for example, memory. Memory can be volatile or non-volatile, or it can include both volatile and non-volatile memory. Non-volatile memory includes, but is not limited to, read-only memory (ROM) and programmable read-only memory (PROM). Volatile memory can be random access memory (RAM), which serves as an external cache.

[0131] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A DC microgrid power supply system, characterized in that, The DC microgrid power supply system is connected to the air conditioning equipment via a DC bus, and the DC microgrid power supply system is used to supply power to the air conditioning equipment through the DC bus. The DC microgrid power supply system includes: A voltage sampler is configured to: collect the bus voltage of the DC bus at the current sampling moment when the air conditioning equipment is running; The controller is configured as follows: Obtain the first DC microgrid current and DC microgrid voltage of the DC microgrid power supply system at the current sampling time; The first DC microgrid power of the DC microgrid power supply system is obtained by calculating the product of the first DC microgrid current and the DC microgrid voltage. Based on the voltage difference between the DC microgrid voltage and the bus voltage, calculate the microgrid current change during the operation of the DC microgrid power supply system; Based on the microgrid current change, the first DC microgrid current, and the DC microgrid voltage, predict the second DC microgrid power of the DC microgrid power supply system at the next sampling time. The difference between the power of the first DC microgrid and the power of the second DC microgrid is used as the droop adjustment power, and a control command containing the droop adjustment power is sent to the air conditioning device. The air conditioning unit is configured to respond to the control command to adjust the operating power of the air conditioning unit according to the droop adjustment power.

2. The DC microgrid power supply system according to claim 1, characterized in that, The controller, based on the microgrid current change, the first DC microgrid current, and the DC microgrid voltage, predicts the second DC microgrid power of the DC microgrid power supply system at the next sampling time, and is configured as follows: The change in microgrid current is summed with the first DC microgrid current to predict the second DC microgrid current at the next sampling time. The product of the DC microgrid voltage and the second DC microgrid current is determined as the power of the second DC microgrid.

3. The DC microgrid power supply system according to claim 1, characterized in that, The controller, based on the voltage difference between the DC microgrid voltage and the bus voltage, calculates the microgrid current change during the operation of the DC microgrid power supply system, and is configured as follows: Calculate the ratio of the voltage difference to the preset DC microgrid reactance in the DC microgrid power supply system to obtain the instantaneous rate of change of current in the DC microgrid power supply system; The product of the instantaneous rate of change of current and the preset sampling period is determined as the change in microgrid current.

4. The DC microgrid power supply system according to claim 3, characterized in that, Before the controller calculates the ratio of the voltage difference to the preset DC microgrid reactance in the DC microgrid power supply system to obtain the instantaneous rate of change of the current in the DC microgrid power supply system, it is further configured as follows: Obtain the predicted third DC microgrid current at the previous sampling time; the third DC microgrid current is predicted based on the change in microgrid current at the previous sampling time and the first DC microgrid current; The difference between the first DC microgrid current and the third DC microgrid current is calculated to obtain the current prediction deviation; If the current prediction deviation is greater than the preset current deviation, then the preset DC microgrid reactance is calibrated.

5. The DC microgrid power supply system according to any one of claims 1-4, characterized in that, The controller uses the difference between the power of the first DC microgrid and the power of the second DC microgrid as the droop adjustment power, and is configured as follows: If the difference is positive, the difference is amplified based on the first adjustment coefficient to obtain the droop adjustment power; If the difference is negative, the difference is reduced based on the second adjustment coefficient to obtain the droop adjustment power.

6. The DC microgrid power supply system according to any one of claims 1-4, characterized in that, The controller uses the difference between the power of the first DC microgrid and the power of the second DC microgrid as the droop adjustment power, and after sending a control command containing the droop adjustment power to the air conditioning device, it is further configured to: Obtain the actual regulating power of the air conditioning equipment; Calculate the adjustment deviation between the actual adjustment power and the droop adjustment power; If the adjustment deviation is greater than the preset deviation threshold, the power adjustment step size of the air conditioning equipment is adjusted; the power adjustment step size is used to describe the power amplitude when the air conditioning equipment adjusts its operating power in a single adjustment.

7. The DC microgrid power supply system according to any one of claims 1-4, characterized in that, The controller is also configured to: If the absolute value of the droop adjustment power is greater than a preset power threshold, then the preset sampling period between the current sampling time and the next sampling time is shortened. If the absolute value of the droop adjustment power is less than or equal to the preset power threshold, then the preset sampling period is maintained or extended.

8. A control method for a DC microgrid power supply system, characterized in that, This system is applied to a DC microgrid power supply system, which is connected to air conditioning equipment via a DC bus. The DC microgrid power supply system is used to supply power to the air conditioning equipment through the DC bus. The control method for the DC microgrid power supply system includes: When the air conditioning equipment is running, the bus voltage of the DC bus is collected at the current sampling time. Obtain the first DC microgrid current and DC microgrid voltage of the DC microgrid power supply system at the current sampling time; The first DC microgrid power of the DC microgrid power supply system is obtained by calculating the product of the first DC microgrid current and the DC microgrid voltage. Based on the voltage difference between the DC microgrid voltage and the bus voltage, calculate the microgrid current change during the operation of the DC microgrid power supply system; Based on the microgrid current change, the first DC microgrid current, and the DC microgrid voltage, predict the second DC microgrid power of the DC microgrid power supply system at the next sampling time. The difference between the power of the first DC microgrid and the power of the second DC microgrid is used as the droop adjustment power, and a control command containing the droop adjustment power is sent to the air conditioning device. The air conditioning unit is configured to respond to the control command to adjust the operating power of the air conditioning unit according to the droop adjustment power.

9. The control method for a DC microgrid power supply system according to claim 8, characterized in that, The step of predicting the power of the second DC microgrid of the DC microgrid power supply system at the next sampling time based on the microgrid current change, the first DC microgrid current, and the DC microgrid voltage includes: The change in microgrid current is summed with the first DC microgrid current to predict the second DC microgrid current at the next sampling time. The product of the DC microgrid voltage and the second DC microgrid current is determined as the power of the second DC microgrid.

10. The control method for a DC microgrid power supply system according to claim 8, characterized in that, The calculation of the microgrid current change during operation of the DC microgrid power supply system based on the voltage difference between the DC microgrid voltage and the bus voltage includes: Calculate the ratio of the voltage difference to the preset DC microgrid reactance in the DC microgrid power supply system to obtain the instantaneous rate of change of current in the DC microgrid power supply system; The product of the instantaneous rate of change of current and the preset sampling period is determined as the change in microgrid current.

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