A direct current building air conditioner active response method and system

Abstract

This invention belongs to the field of DC building technology, specifically relating to a method and system for active response of DC building air conditioning. Addressing the deficiency in existing technologies that do not disclose how DC equipment participates in active power response in DC buildings, this invention adopts the following technical solution: A method for active response of DC building air conditioning, comprising: acquiring air conditioning-related information and DC bus voltage; adjusting the DC bus voltage according to received power consumption adjustment demands to obtain DC bus voltage change information; sending the DC bus voltage change information to the air conditioning system via the DC bus, comparing the indoor temperature with preset upper and lower limits of the indoor set temperature; determining whether to update the indoor set temperature based on the DC bus voltage change information and the comparison information; and adjusting the air conditioning operating power according to the updated indoor set temperature to achieve active response. The method of this invention can adjust the power consumption of the air conditioning system according to the demands of the AC power grid, achieving active response.

Description

Technical Field

[0001] This invention belongs to the field of DC building technology, specifically relating to a DC building air conditioning active response method and system. Background Technology

[0002] The randomness and volatility of renewable energy generation pose significant challenges to the safe and stable operation of urban power grids. The development of large-scale renewable energy inevitably requires power grid systems to possess sufficient flexibility and regulation capabilities. Besides various large-scale energy storage methods such as batteries, pumped hydro storage, and compressed air storage, utilizing the inherent adjustability of the power grid load itself is gradually becoming a primary approach. Electricity consumption in the building sector constitutes a major component of total electricity consumption, and the direct current (DC) conversion of building power is also a development trend. Among these, air conditioning systems, with their high energy consumption and high controllability of aggregated dispatching, have become a key focus for flexible load control in buildings.

[0003] The "Design Standard for DC Power Distribution in Civil Buildings T / CABEE 030—2022" (hereinafter referred to as the "Standard"), the first technical standard focusing on the engineering application of DC power distribution systems in the building field, was also released in 2022. This standard discloses a DC building system where, by setting different energy management strategies, the DC system can use changes in the DC bus voltage to transmit power regulation information to equipment. The converter can automatically switch control functions according to the DC bus voltage state, realizing autonomous power regulation of distributed power sources and AC / DC conversion equipment. This method of power regulation using voltage in DC systems can simultaneously address the control requirements of both steady-state energy and transient power. Because it does not rely on complex control algorithms and high-intensity communication, it helps reduce construction costs and maintenance requirements. The "Standard" refers to this method of power regulation—transmitting information through voltage changes and having equipment respond autonomously according to the DC voltage state—as "active power response," to distinguish it from the concept of voltage droop.

[0004] However, the standard only discloses the general idea and direction, without revealing specific implementation details. Those skilled in the art are still exploring how DC equipment can specifically participate in active power response. Summary of the Invention

[0005] This invention addresses the deficiency in existing technologies that do not disclose how DC equipment in DC buildings participates in active power response. It provides a DC building air conditioning active response method that adjusts the indoor set temperature of the terminal air conditioners by using the building's DC bus voltage signal, thereby regulating the building's air conditioning power consumption. This fully utilizes the flexible adjustment capability of the building air conditioning system load, improves the demand response capability of building air conditioning to the AC power grid, and enhances the stability of the power system. This invention also provides a DC building air conditioning active response system.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a DC building air conditioning active response method, the DC building air conditioning active response method comprising:

[0007] Step S01: Obtain the air conditioner operating status, indoor set temperature, indoor set temperature upper and lower limits, indoor temperature, and DC bus voltage;

[0008] Step S02: Adjust the DC bus voltage according to the received AC power grid demand for building power regulation, and obtain DC bus voltage change information;

[0009] Step S03: Send DC bus voltage change information to the air conditioning system via DC bus, and compare the indoor temperature with the preset upper and lower limits of the indoor set temperature.

[0010] Step S04: Based on the DC bus voltage change information and comparison information, decide whether to update the indoor set temperature;

[0011] Step S05: Adjust the air conditioner's operating power according to the updated indoor set temperature to achieve active response.

[0012] The DC building air conditioning active response method of the present invention realizes power control of the air conditioning system distributed at the DC building terminal through a unified DC bus voltage value signal, avoiding the problems of system cost and control efficiency caused by complicated communication, and can adjust the power consumption of the air conditioning system according to the needs of the AC power grid to achieve active response.

[0013] As an improvement, in step S02, the DC bus voltage is increased when the AC grid requires the DC building to increase its power consumption; and the DC bus voltage is decreased when the AC grid requires the DC building to reduce its power consumption.

[0014] As an improvement, in step S02, the DC bus voltage change value is calculated based on the received building power consumption adjustment demand and the number of DC building devices participating in the response.

[0015] As an improvement, in step S02, when the rated voltage of the DC bus... U When the value is within a certain deviation range, it indicates that no demand response command has been received from the AC power grid, and it is due to its own fluctuation. In this case, no DC bus voltage change information is sent.

[0016] As an improvement, in step S02, when the DC bus voltage... U dc Compared to its rated voltage U 0. Outside a certain deviation range, DC bus voltage change information is sent to the air conditioning system via the DC bus; in step S04, when the DC bus voltage... Udc When the value is too high, the indoor set temperature change plan value With DC bus voltage U dc As the DC bus voltage increases, it eventually stabilizes at its maximum value; U dc When the temperature is low, the indoor set temperature change plan value With DC bus voltage U dc It decreases as it decreases, eventually stabilizing at its minimum value.

[0017] As an improvement, in step S03, the indoor temperature is compared with the upper or lower limit of the indoor set temperature based on the positive or negative value of the change in DC bus voltage.

[0018] As an improvement, in step S04, the indoor set temperature update process also satisfies the following formula:

[0019]

[0020] in, Set the actual temperature change value for the indoor environment. This is the planned value for indoor set temperature change calculated based on the voltage command. k The user-defined adjustment depth is 0 to 1. k A value of 0 indicates that the user does not interfere with the voltage regulation result. k A value of 1 indicates that the user does not participate in setting the indoor temperature.

[0021] As an improvement, for fixed-frequency air conditioners, start-stop control is adopted, and a start-stop control is set. T max and T min These are the upper and lower limits for setting the indoor temperature, respectively. The indoor temperature is at... T set1 +δ T to T max The air conditioning in the area was originally off, but when the indoor set temperature was lowered from the rated setting to... T set1 Afterwards, it will be in a pre-on state, and the air conditioner's power consumption will increase according to changes in the indoor set temperature; when the indoor temperature is... T min to T set2 -δ T The air conditioning in the area was originally on, but when the indoor set temperature was increased from the rated setting to... T set2 Afterwards, it will be in a pre-off state, and the power consumption of the air conditioner will decrease as the indoor set temperature changes.

[0022] As an improvement, for inverter air conditioners, the difference between the indoor set temperature and the indoor temperature is proportionally adjusted to the compressor operating frequency. The change in the compressor operating frequency will follow the change in the difference between the indoor set temperature and the indoor temperature. When the indoor temperature is higher than the indoor set temperature, the compressor frequency increases and the power consumption of the air conditioner increases. When the indoor temperature is lower than the indoor set temperature, the compressor frequency decreases and the power consumption of the air conditioner decreases.

[0023] A DC building air conditioning active response system, the DC building air conditioning active response system comprising:

[0024] Power distribution system, including DC bus;

[0025] The intelligent energy manager, connected to the AC grid and DC bus at both ends, manages the power flow between the AC grid and the building's DC circuit, maintains the DC bus voltage, receives demand response commands from the AC grid and controls the DC bus voltage changes accordingly, and sends the DC bus voltage signal to the voltage response device.

[0026] The air conditioner has a voltage response device that receives a DC bus voltage signal and adjusts the indoor set temperature and operating power of the air conditioner according to the relationship between the DC bus voltage signal and the upper and lower limits of the indoor temperature, in response to the demand response command of the AC power grid.

[0027] The beneficial effects of the DC building air conditioning active response method of the present invention are: the power control of the air conditioning system distributed at the DC building terminal is realized by a unified DC bus voltage signal, avoiding the problems of system cost and control efficiency caused by complicated communication, and the power consumption of the air conditioning system can be adjusted according to the needs of the AC power grid to achieve active response.

[0028] The beneficial effects of the DC building air conditioning active response system of the present invention are: the power control of the air conditioning system distributed at the DC building terminal is realized through a unified DC bus voltage signal, avoiding the problems of system cost and control efficiency caused by complicated communication, and the power consumption of the air conditioning system can be adjusted according to the needs of the AC power grid to achieve active response. Attached Figure Description

[0029] Figure 1 This is a structural block diagram of an air conditioning active response system according to an embodiment of the present invention.

[0030] Figure 2 This is a schematic diagram of the air conditioning active response method under cooling conditions according to an embodiment of the present invention.

[0031] Figure 3 This is a schematic diagram illustrating the response relationship between the air conditioner set temperature and the DC bus voltage in an embodiment of the present invention.

[0032] Figure 4 This is a schematic diagram of the control of a fixed-frequency air conditioner according to an embodiment of the present invention.

[0033] Figure 5 This is a schematic diagram of the control of a variable frequency air conditioner according to an embodiment of the present invention. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be explained and described below. However, the following embodiments are only preferred embodiments of the present invention and not all of them. Other embodiments obtained by those skilled in the art based on the embodiments in the implementation methods without creative effort are all within the protection scope of the present invention.

[0035] Example of a DC building air conditioning active response system

[0036] See Figure 1 An embodiment of the present invention provides a DC building air conditioning active response system, the DC building air conditioning active response system comprising:

[0037] Power distribution system, including DC bus;

[0038] The intelligent energy manager, connected to the AC grid and DC bus at both ends, manages the power flow between the AC grid and the building's DC circuit, maintains the DC bus voltage, receives demand response commands from the AC grid and controls the DC bus voltage changes accordingly, and sends the DC bus voltage signal to the voltage response device.

[0039] The air conditioner has a voltage response device that receives a DC bus voltage signal and adjusts the indoor set temperature and operating power of the air conditioner according to the relationship between the DC bus voltage signal and the upper and lower limits of the indoor temperature, in response to the demand response command of the AC power grid.

[0040] Implementation Examples of Active Response Methods for DC Building Air Conditioning

[0041] See Figures 2 to 5 An embodiment of the present invention provides an active response method for DC building air conditioning, the active response method for DC building air conditioning comprising:

[0042] Step S01: Obtain the air conditioner operating status, indoor set temperature, indoor set temperature upper and lower limits, indoor temperature, and DC bus voltage;

[0043] Step S02: Adjust the DC bus voltage according to the received AC power grid demand for building power regulation, and obtain DC bus voltage change information;

[0044] Step S03: Send DC bus voltage change information to the air conditioning system via DC bus, and compare the indoor temperature with the preset upper and lower limits of the indoor set temperature.

[0045] Step S04: Based on the DC bus voltage change information and comparison information, decide whether to update the indoor set temperature;

[0046] Step S05: Adjust the air conditioner's operating power according to the updated indoor set temperature to achieve active response.

[0047] In this embodiment, step S01, the air conditioner's operating status mainly refers to whether the air conditioner is turned on or off. The indoor set temperature is the temperature set by the user; for example, if the user sets the temperature to 28℃ in summer, 28℃ is the indoor set temperature. The upper and lower limits of the indoor set temperature are determined by human health and comfort requirements and user behavior, etc., and can be set by the user or preset by the manufacturer. For example, if the user sets the indoor set temperature to 28℃ in summer, the upper and lower limits of the indoor set temperature are also set to ±2℃. The indoor temperature is read in real time. Because the user may adjust the indoor set temperature, the indoor set temperature can also be read in real time. The DC bus voltage is obtained and adjusted by the intelligent energy manager.

[0048] In this embodiment, in step S02, the DC bus voltage is increased when the AC power grid requires the DC building to increase its power consumption; and the DC bus voltage is decreased when the AC power grid requires the DC building to reduce its power consumption.

[0049] In this embodiment, in step S02, the DC bus voltage change value is calculated based on the building power adjustment demand received from the AC power grid and the number of DC building devices participating in the response.

[0050] In this embodiment, in step S02, when the rated voltage of the DC bus... U When the value is within a certain deviation range, it indicates that no demand response command has been received from the AC power grid, and it is due to its own fluctuation. In this case, no DC bus voltage change information is sent.

[0051] In this embodiment, in step S02, when the DC bus voltage U dc Compared to its rated voltage U 0. Outside a certain deviation range, DC bus voltage change information is sent to the air conditioning system via the DC bus; in step S04, when the DC bus voltage... U dc When the value is too high, the indoor set temperature change plan value With DC bus voltage U dc As the DC bus voltage increases, it eventually stabilizes at its maximum value; U dcWhen the temperature is low, the indoor set temperature change plan value With DC bus voltage U dc It decreases as it decreases, eventually stabilizing at its minimum value.

[0052] In this embodiment, in step S02, when the DC bus voltage U dc Compared to its rated voltage U 0. Outside a certain deviation range, determine the voltage change between the current moment and the previous moment. Is it greater than 0?

[0053] In this embodiment, in step S03, the indoor temperature is compared with the upper or lower limit of the indoor set temperature based on the positive or negative value of the change in DC bus voltage.

[0054] In this embodiment, the indoor set temperature update process in step S04 also satisfies the following formula:

[0055]

[0056] in, Set the actual temperature change value for the indoor environment. This is the planned value for indoor set temperature change calculated based on the voltage command. k The user-defined adjustment depth is 0 to 1. k A value of 0 indicates that the user does not interfere with the voltage regulation result. k A value of 1 indicates that the user does not participate in setting the indoor temperature.

[0057] More specifically, in this embodiment, step S03 includes step S031, when >0 means that the AC power grid requires the building to increase its power consumption, and the indoor temperature is compared with the indoor temperature setting lower limit; step S032, when <0 means that the AC power grid requires the building to reduce its power consumption, comparing the indoor temperature with the upper limit of the indoor temperature setting:

[0058] More specifically, in this embodiment, step S04 includes step S041: When the indoor temperature is not higher than the lower limit of the set temperature, in order to ensure the normal use needs of the user, the air conditioner's operating power should not be increased by lowering the set temperature. For the individual air conditioner in the room, the indoor set temperature remains unchanged at the current value; S042: When the indoor temperature is higher than the lower limit of the set temperature, the voltage response device calculates the change value of the indoor set temperature based on the change value of the DC bus voltage, and lowers the indoor set temperature based on the current set temperature.

[0059] Specifically, in this embodiment, step S04 includes step S043: when the indoor temperature is not lower than the upper limit of the set temperature, in order to ensure the normal use needs of users, the air conditioner's operating power should not be reduced by raising the set temperature. For the individual air conditioner in the room, the indoor set temperature remains unchanged at the current value. Step S044: when the indoor temperature is lower than the upper limit of the set temperature, the voltage response device calculates the change value of the indoor set temperature based on the change value of the DC bus voltage, and raises the indoor set temperature based on the current set temperature.

[0060] In this embodiment, see Figure 4 For fixed-frequency air conditioners, start-stop control is used, and the following settings are made: T max and T min These are the upper and lower limits for setting the indoor temperature, respectively. The indoor temperature is at... T set1 +δ T to T max The air conditioning in the area was originally off, but when the indoor set temperature was lowered from the rated setting to... T set1 Afterwards, it will be in a pre-on state, and the air conditioner's power consumption will increase according to changes in the indoor set temperature; when the indoor temperature is... T min to T set2 -δ T The air conditioning in the area was originally on, but when the indoor set temperature was increased from the rated setting to... T set2 Afterwards, it will be in a pre-off state, and the power consumption of the air conditioner will decrease as the indoor set temperature changes.

[0061] In this embodiment, see Figure 5 For inverter air conditioners, the difference between the indoor set temperature and the indoor temperature is proportionally adjusted to the compressor operating frequency. The change in the compressor operating frequency will follow the change in the difference between the indoor set temperature and the indoor temperature. When the indoor temperature is higher than the indoor set temperature, the compressor frequency increases and the power consumption of the air conditioner increases. When the indoor temperature is lower than the indoor set temperature, the compressor frequency decreases and the power consumption of the air conditioner decreases.

[0062] The following explanation uses a DC-DC building as an example. Assume the building has 100 inverter air conditioners, and during a certain time period, all relevant parameters, including operating conditions and settings, are identical for all 100 air conditioners. The response process is as follows:

[0063] Step S01: Obtain the operating status of 100 inverter air conditioners as follows: all are working, the indoor set temperature is 28℃, the upper limit of the indoor set temperature is 30℃, the lower limit is 26℃, the indoor temperature is 28℃, the DC bus voltage is 100V, and the power of a single air conditioner is 2000W. Assuming that only the air conditioners are running and other electrical appliances are not working, the total power is 200kW.

[0064] Step S02: The received AC grid demand for power regulation in the building is a reduction of 20kW. Based on this demand and the number of devices participating in the DC response in the building, the change in DC bus voltage is calculated. Here, it is assumed that there are 100 inverter air conditioners and only they participate in the response; the calculated change in DC bus voltage is a reduction of 10V, down to 90V. When calculating the change in DC bus voltage, in addition to considering the number of devices participating in the response, information such as their type and adjustable power can also be taken into account. The general principle is that the more devices participating in the response, the smaller the change in DC bus voltage and the smaller the power change of individual devices.

[0065] Step S03: Send DC bus voltage change information to the voltage response device of the air conditioning system via the DC bus. Specifically, the voltage response device receives information indicating a 90% power reduction or a 200W power reduction. After receiving this information... 0 means that the AC power grid requires the building to reduce its power consumption, comparing the indoor temperature with the upper limit of the indoor temperature setting, i.e., comparing 28℃ with 30℃.

[0066] Step S04: When the indoor temperature of 28℃ is lower than the upper limit of the set temperature of 30℃, the voltage response device calculates the change value of the indoor set temperature based on the change value of the DC bus voltage and decides to increase the indoor set temperature based on the current set temperature.

[0067] Step S05: The air conditioning system updates the indoor set temperature and adjusts the air conditioning operating power to achieve active response.

[0068] In step S05, if the indoor set temperature of 30℃ or lower meets the demand, the indoor set temperature is raised to the corresponding temperature. If the indoor set temperature of 30℃ still does not meet the demand, the indoor set temperature for some users is further raised, or even some air conditioners are turned off, according to the users' preset permissions. To reduce the impact of changing the indoor set temperature on users, the indoor set temperature can be raised for some users at one time and raised for another group of users at another time, while the indoor set temperature for the first group of users is lowered – a rotating adjustment method. During the response process, the intelligent energy manager calculates the total DC building power in real time or at intervals to see if it meets the response requirements. If it does not meet the response requirements, the aforementioned steps are readjusted.

[0069] The DC building air conditioning active response method in this embodiment realizes power control of air conditioning systems distributed at the DC building terminals through a unified DC bus voltage signal. This avoids problems such as system cost and control efficiency caused by complex communication. Furthermore, it can adjust the power consumption of the air conditioning system according to the needs of the AC power grid, thus achieving active response. The air conditioner adjusts the indoor set temperature based on the received DC bus voltage change information, thereby adjusting the air conditioning power. The fewer the number of devices participating in the response, and the greater the magnitude (absolute value or proportion) of the DC bus voltage change, the more adjustments are made.

[0070] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that the present invention includes, but is not limited to, the content described in the above specific embodiments. Any modifications that do not depart from the functional and structural principles of the present invention will be included within the scope of the claims.

Claims

1. A DC building air conditioning active response method, characterized in that: The active response method for DC building air conditioning includes: Step S01: Obtain the air conditioner operating status, indoor set temperature, indoor set temperature upper and lower limits, indoor temperature, and DC bus voltage; Step S02: Adjust the DC bus voltage according to the received AC power grid demand for building power regulation, and obtain DC bus voltage change information; Step S03: Send DC bus voltage change information to the air conditioning system via DC bus, and compare the indoor temperature with the preset upper and lower limits of the indoor set temperature. Step S04: Based on the DC bus voltage change information and comparison information, decide whether to update the indoor set temperature; Step S05: Adjust the air conditioner's operating power according to the updated indoor set temperature to achieve active response.

2. The active response method for DC building air conditioning according to claim 1, characterized in that: In step S02, the DC bus voltage is increased when the AC grid requires the DC building to increase its power consumption; the DC bus voltage is decreased when the AC grid requires the DC building to reduce its power consumption.

3. The active response method for DC building air conditioning according to claim 2, characterized in that: In step S02, the DC bus voltage change value is calculated based on the received building power adjustment demand and the number of devices participating in the response in the DC building.

4. The active response method for DC building air conditioning according to claim 1, characterized in that: In step S02, when the rated voltage of the DC bus... U When the value is within a certain deviation range, it indicates that no demand response command has been received from the AC power grid, and it is due to its own fluctuation. In this case, no DC bus voltage change information is sent.

5. The active response method for DC building air conditioning according to claim 1, characterized in that: In step S02, when the DC bus voltage U dc Compared to its rated voltage U 0. Outside a certain deviation range, DC bus voltage change information is sent to the air conditioning system via the DC bus; in step S04, when the DC bus voltage... U dc When the value is too high, the indoor set temperature change plan value With DC bus voltage U dc As the DC bus voltage increases, it eventually stabilizes at its maximum value; U dc When the temperature is low, the indoor set temperature change plan value With DC bus voltage U dc It decreases as it decreases, eventually stabilizing at its minimum value.

6. The active response method for DC building air conditioning according to claim 1, characterized in that: In step S03, the indoor temperature is compared with the upper or lower limit of the indoor set temperature based on the positive or negative value of the DC bus voltage change.

7. The active response method for DC building air conditioning according to claim 1, characterized in that: In step S04, the indoor set temperature update process also satisfies the following formula: in, Set the actual temperature change value for the indoor environment. This is the planned value for indoor set temperature change calculated based on the voltage command. k The user-defined adjustment depth is 0 to 1. k A value of 0 indicates that the user does not interfere with the voltage regulation result. k A value of 1 indicates that the user does not participate in setting the indoor temperature.

8. The active response method for DC building air conditioning according to claim 1, characterized in that: For fixed-frequency air conditioners, start-stop control is used, and the following settings are made: T max and T min These are the upper and lower limits for setting the indoor temperature, respectively. The indoor temperature is at... T set1 +δ T to T max The air conditioning in the area was originally off, but when the indoor set temperature was lowered from the rated setting to... T set1 Afterwards, it will be in a pre-on state, and the air conditioner's power consumption will increase according to changes in the indoor set temperature; when the indoor temperature is... T min to T set2 -δ T The air conditioning in the area was originally on, but when the indoor set temperature was increased from the rated setting to... T set2 Afterwards, it will be in a pre-off state, and the power consumption of the air conditioner will decrease as the indoor set temperature changes.

9. The active response method for DC building air conditioning according to claim 1, characterized in that: For inverter air conditioners, the difference between the indoor set temperature and the indoor temperature is proportionally adjusted to the compressor operating frequency. The change in the compressor operating frequency will follow the change in the difference between the indoor set temperature and the indoor temperature. When the indoor temperature is higher than the indoor set temperature, the compressor frequency increases and the power consumption of the air conditioner increases. When the indoor temperature is lower than the indoor set temperature, the compressor frequency decreases and the power consumption of the air conditioner decreases.

10. A DC building air conditioning active response system, characterized in that: The DC building air conditioning active response system includes: Power distribution system, including DC bus; The intelligent energy manager, connected to the AC grid and DC bus at both ends, manages the power flow between the AC grid and the building's DC circuit, maintains the DC bus voltage, receives demand response commands from the AC grid and controls the DC bus voltage changes accordingly, and sends the DC bus voltage signal to the voltage response device. The air conditioner has a voltage response device that receives a DC bus voltage signal and adjusts the indoor set temperature and operating power of the air conditioner according to the relationship between the DC bus voltage signal and the upper and lower limits of the indoor temperature, in response to the demand response command of the AC power grid.

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