Air conditioning system and energy management method in air conditioning system

Abstract

An air conditioning system (50) comprises: a variable power source device (1) that is capable of changing an output voltage; air conditioners (3a-3c) that operate upon receiving DC voltage or AC voltage output from the variable power source device (1); and a centralized management controller (2) that manages the variable power source device (1) and the air conditioners (3a-3c). The variable power source device (1) can output at least one of DC, single-phase AC, and three-phase AC. The variable power source device (1) and the centralized management controller (2) can mutually transmit and receive data. The air conditioners (3a-3c) and the centralized management controller (2) can mutually transmit and receive data.

Description

Air conditioning system and energy management method in an air conditioning system

[0001] The present disclosure relates to an air conditioning system in which one or more air conditioners are managed by a centralized management controller and an energy management method in the air conditioning system.

[0002] In Patent Document 1 below, in an air conditioner to which only DC power is input, high-voltage DC power having a first DC voltage value is input to the compressor drive inverter of the outdoor unit, and a power conversion circuit group including a drive circuit of the indoor unit and a drive circuit other than the compressor drive inverter in the outdoor unit is disclosed with a configuration in which low-voltage DC power having a second DC voltage value lower than the first DC voltage value is input.

[0003] Japanese Patent Application Laid-Open No. 2012-83063

[0004] However, in the case of the air conditioner described in Patent Document 1, it is not considered that the DC power supply source is renewable energy such as solar power generation. In the air conditioner described in Patent Document 1, there is no means for transmitting information on the excess or shortage of power generated by renewable energy to the air conditioner, so there is a problem that energy management such as demand response cannot be performed.

[0005] The present disclosure has been made in view of the above, and an object thereof is to obtain an air conditioning system capable of performing energy management such as demand response.

[0006] To solve the above-described problems and achieve the object, an air conditioning system according to the present disclosure includes a variable power supply device capable of changing an output voltage, one or more air conditioners that receive and operate a DC voltage or an AC voltage output from the variable power supply device, and a centralized management controller that manages the variable power supply device and the air conditioners. The variable power supply device is configured to be able to output at least one of DC, single-phase AC, and three-phase AC. The variable power supply device and the centralized management controller are configured to be able to transmit and receive data to and from each other. The air conditioner and the centralized management controller are configured to be able to transmit and receive data to and from each other.

[0007] The air conditioning system described herein offers the benefit of enabling energy management, such as demand response.

[0008] Figures showing an example configuration of an air conditioning system according to Embodiment 1 Figures showing an example configuration of an air conditioner, which is a component of the air conditioning system according to Embodiment 1 Figures showing an example of hardware configuration for realizing a centralized control controller, which is a component of the air conditioning system according to Embodiment 1 Figures showing a first configuration example of a power converter provided in the outdoor unit of an air conditioner, which is a component of the air conditioning system according to Embodiment 1 Figures showing a second configuration example of a power converter provided in the outdoor unit of an air conditioner, which is a component of the air conditioning system according to Embodiment 1 Figures showing a third configuration example of a power converter provided in the outdoor unit of an air conditioner, which is a component of the air conditioning system according to Embodiment 1 Figure 1 shows an example of the configuration of the inverter control unit when the component air conditioner has a restricted energization function. Figure 8 shows a flowchart for explaining the operation of the centralized control controller in Embodiment 1, showing the relationship between the items of power change parameters that can be changed by the control flow shown in Figure 8 and the direction of increase or decrease of their values. Figure 13 shows an example of the DC voltage command value for explaining the control flow shown in Figure 10, a first flowchart for explaining the operation of the centralized control controller in Embodiment 2. Figure 13 shows an example of the DC voltage command value for explaining the control flow shown in Figure 10, a second flowchart for explaining the operation of the centralized control controller in Embodiment 2, and an example of the DC voltage command value for explaining the control flow shown in Figure 13.

[0009] The air conditioning system and energy management method in the air conditioning system according to the embodiments of this disclosure will be described in detail below with reference to the attached drawings. In the following description, multiple components of the same type will be indicated by subscripts, but the subscripts will be omitted as appropriate when describing them without distinguishing between them.

[0010] Embodiment 1. Figure 1 is a diagram showing an example of the configuration of an air conditioning system 50 according to Embodiment 1. The air conditioning system 50 according to Embodiment 1 comprises a variable power supply device 1 that can change the output voltage, air conditioners (hereinafter abbreviated as "air conditioners") 3a to 3c that operate by receiving DC voltage or AC voltage output from the variable power supply device 1, and a centralized control controller 2 that manages the variable power supply device 1 and the air conditioners 3a to 3c. In Figure 1, three air conditioners 3a to 3c are shown as an example, but the number of air conditioners 3 can be one or more.

[0011] As shown in Figure 1, the variable power supply unit 1 includes an external communication device 10, power converters 11a to 11c, and a switch 12, and the centralized control controller 2 includes an external communication device 20. The air conditioner 3a includes a power converter 31a and an external communication device 32a. Similarly, the air conditioner 3b includes a power converter 31b and an external communication device 32b, and the air conditioner 3c includes a power converter 31c and an external communication device 32c.

[0012] The variable power supply unit 1 is configured to output at least one of DC, single-phase AC, and three-phase AC. The switch 12 has a DC terminal 13, a single-phase AC terminal 14, a three-phase AC terminal 15, an open terminal 16, and an output terminal 17. In the switch 12, the output terminal 17 can be switched to any of the terminals among the DC terminal 13, single-phase AC terminal 14, three-phase AC terminal 15, and open terminal 16. The switch 12 can be configured as a relay circuit or the like.

[0013] The power converter 11a provided in the variable power supply unit 1 receives AC power from the AC power source 52, or receives DC power from renewable energy sources 54 such as solar power generation, generates DC power, and supplies power to the air conditioner 3 via the DC terminal 13 and output terminal 17. The power converter 11b provided in the variable power supply unit 1 receives AC power from the AC power source 52, or receives DC power from renewable energy sources 54 such as solar power generation, generates single-phase AC power, and supplies power to the air conditioner 3 via the single-phase AC terminal 14 and output terminal 17. The power converter 11c provided in the variable power supply unit 1 receives AC power from the AC power source 52, or receives DC power from renewable energy sources 54 such as solar power generation, generates three-phase AC power, and supplies power to the air conditioner 3 via the three-phase AC terminal 15 and output terminal 17. When the variable power supply unit 1 does not supply power to the air conditioner 3, the connection destination of the output terminal 17 is switched to the open terminal 16.

[0014] As mentioned above, the variable power supply unit 1 is equipped with an external communication device 10, and the centralized control controller 2 is equipped with an external communication device 20. The external communication devices 10 and 20 enable the variable power supply unit 1 and the centralized control controller 2 to send and receive data to and from each other. Also, as mentioned above, each air conditioner 3 is equipped with an external communication device 32. The external communication devices 20 and 32 enable the air conditioner 3 and the centralized control controller 2 to send and receive data to and from each other. The detailed operation of the centralized control controller 2 will be described later.

[0015] The communication between external communication device 10 and external communication device 20, and the communication between external communication device 20 and external communication device 32 may be general wired communication such as serial communication, LAN (Local Area Network) communication, CAN (Controller Area Network) communication, or PLC (Power Line Communication) communication, or general wireless communication such as Wi-Fi (Wireless Fidelity), or communication using a proprietary communication standard considering security.

[0016] Figure 2 shows an example of the configuration of an air conditioner 3, which is a component of the air conditioning system 50 according to Embodiment 1. The air conditioner 3 comprises an outdoor unit 30 and an indoor unit 40. The outdoor unit 30 and the indoor unit 40 form a complete refrigeration cycle together, performing the function of the air conditioner 3.

[0017] The outdoor unit 30 includes, in addition to the power converter 31 and external communication device 32 shown in Figure 1, an outdoor unit control device 33, an outdoor unit heat exchanger 34, an outdoor unit fan 35, an outdoor unit communication device 36, and a compressor 37. The indoor unit 40 includes a power converter 41, an indoor unit control device 43, an indoor unit heat exchanger 44, an indoor unit fan 45, an indoor unit communication device 46, a human detection sensor 47, and an airflow direction adjustment means 48. Although Figure 2 shows a configuration in which the outdoor unit 30 is equipped with the external communication device 32 shown in Figure 1, the external communication device 32 may also be equipped in the indoor unit 40. Furthermore, both the outdoor unit 30 and the indoor unit 40 may be equipped with an external communication device 32 for communicating with the centralized control controller 2. In this case, the outdoor unit communication device 36 and the indoor unit communication device 46 may be omitted, and the centralized control controller 2 may relay the communication between the outdoor unit 30 and the indoor unit 40.

[0018] The outdoor unit control device 33 controls the temperature of the refrigeration cycle, which consists of a compressor 37, an outdoor unit fan 35, and solenoid valves (not shown) provided in the outdoor unit heat exchanger 34. The outdoor unit control device 33 also controls the operation of the power converter 31 so that the compressor 37 and the outdoor unit fan 35 rotate at a desired rotational speed, and the power converter 31 supplies the necessary power to the compressor 37 and the outdoor unit fan 35. The outdoor unit control device 33 also controls the power converter 31 so that it can supply power to drive the indoor unit fan 45 of the indoor unit 40. The power converter 31 supplies power to drive the indoor unit fan 45 to the power converter 41 of the indoor unit 40.

[0019] The human detection sensor 47 is composed of, for example, a thermopile sensor that calculates and detects the temperature of an object from the infrared energy emitted by the object. The airflow direction adjustment means 48 is composed of, for example, a general louver that adjusts the airflow direction of the indoor unit fan 45 by the angle of a partition plate. The indoor unit control device 43 controls the operation of the indoor unit heat exchanger 44 and the airflow direction adjustment means 48 based on sensor information detected by the human detection sensor 47. The power converter 41 supplies the required power to the indoor unit fan 45 so that the indoor unit fan 45 rotates at the desired rotational speed.

[0020] Figure 3 shows an example of a hardware configuration for realizing a centralized control controller 2, which is a component of the air conditioning system 50 according to Embodiment 1. The centralized control controller 2 is realized by a computer system that includes, in addition to the external communication device 20 described above, a processor 91 that performs various processes, a memory 92 which is the main memory, and a storage device 93 that stores information.

[0021] The processor 91 is an example of a calculation means. The processor 91 may be a calculation means referred to as a microprocessor, microcomputer, CPU (Central Processing Unit), or DSP (Digital Signal Processor). As the memory 92, non-volatile or volatile semiconductor memory such as RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable ROM), or EEPROM (Registered Trademark) (Electrically EPROM) can be used. The storage device 93 stores a program for performing the processing of the centralized management controller 2 described below.

[0022] The above computer system realizes the functions of the centralized management controller 2 described below by having the processor 91 read a program stored in the storage device 93 into the memory 92 and execute it. The memory 92 is also used as temporary memory for each process executed by the processor 91. The program executed by the processor 91 may be provided in a state stored on a storage medium, or it may be provided via a network (not shown).

[0023] Figure 4 shows a first example of the configuration of a power converter 31 provided in the outdoor unit 30 of the air conditioner 3, which is a component of the air conditioning system 50 according to Embodiment 1. The power converter 31 is configured to operate by receiving DC power from a variable power supply 1. The power converter 31 is connected to the variable power supply 1 via a power receiving terminal 70, and its output side is connected to the compressor motor 142.

[0024] The power conversion device 31 comprises a reactor 121, a smoothing capacitor 123, an inverter 141, and an inverter control unit 80. As shown in the figure, the reactor 121 and the smoothing capacitor 123 are inserted between the variable power supply 1 and the inverter 141 for purposes such as stabilizing the voltage applied to the inverter 141, but they may be omitted if they do not adversely affect the operation of the variable power supply 1 and the inverter 141.

[0025] The inverter 141 includes switching elements 156a to 156f connected in a three-phase bridge configuration. The inverter 141 converts the applied DC voltage into a three-phase AC voltage to operate the compressor motor 142.

[0026] The inverter control unit 80 generates a drive signal to drive the switching elements 156a to 156f of the inverter 141 based on the detected current or voltage values ​​detected by a current detection unit, a voltage detection unit, etc. (not shown), and outputs it to the inverter 141. Examples of current detection values ​​include the detected motor current flowing through the compressor motor 142, the detected power supply current flowing through the reactor 121, and the detected capacitor current flowing through the smoothing capacitor 123. Examples of voltage detection values ​​include the detected power supply voltage output by the variable power supply unit 1, the detected capacitor voltage applied to the smoothing capacitor 123, and the detected motor voltage applied to the compressor motor 142.

[0027] Figure 5 shows a second example of the configuration of a power converter 31 provided in the outdoor unit 30 of the air conditioner 3, which is a component of the air conditioning system 50 according to Embodiment 1. The power converter 31 is configured to operate by receiving DC power or single-phase AC power from the variable power supply 1. Similar to Figure 4, the power converter 31 is connected to the variable power supply 1 via the power receiving terminal 70, and the output side is connected to the compressor motor 142. Compared to the configuration in Figure 4, a rectifier circuit 122 is added between the reactor 121 and the smoothing capacitor 123 in Figure 5. The other components are the same as or equivalent to the power converter 31 shown in Figure 4, and the same or equivalent components are denoted by the same reference numerals.

[0028] The rectifier circuit 122 has diodes 152a to 152d that are connected in a full bridge configuration. When DC power is supplied from the variable power supply 1, the rectifier circuit 122 receives a first DC voltage and outputs a second DC voltage. When single-phase AC power is supplied from the variable power supply 1, the rectifier circuit 122 rectifies the received single-phase AC voltage and outputs a second DC voltage. The first DC voltage is the output voltage of the variable power supply 1 when DC power is supplied from the variable power supply 1, and the second DC voltage is the DC voltage applied to the inverter 141. The reactor 121 corrects the power factor of the power supply current flowing between the variable power supply 1 and the rectifier circuit 122.

[0029] Figure 6 shows a third configuration example of a power converter 31 provided in the outdoor unit 30 of the air conditioner 3, which is a component of the air conditioning system 50 according to Embodiment 1. The power converter 31 is configured to operate by receiving DC power or three-phase AC power from the variable power supply 1. Similar to Figure 5, the power converter 31 is connected to the variable power supply 1 via the power receiving terminal 70, and the output side is connected to the compressor motor 142. Compared with the configuration in Figure 5, in Figure 6 the configuration of the rectifier circuit 122 has been changed from a full bridge connection to a three-phase bridge connection. The other components are the same as or equivalent to the power converter 31 shown in Figure 5, and the same or equivalent components are denoted by the same reference numerals.

[0030] The rectifier circuit 122 has diodes 152a to 152f connected in a three-phase bridge configuration. When DC power is supplied from the variable power supply 1, the rectifier circuit 122 receives a first DC voltage and outputs a second DC voltage. When three-phase AC power is supplied from the variable power supply 1, the rectifier circuit 122 rectifies the received three-phase AC voltage and outputs a second DC voltage. The first DC voltage is the output voltage of the variable power supply 1 when DC power is supplied from the variable power supply 1, and the second DC voltage is the DC voltage applied to the inverter 141. Similar to Figure 5, the reactor 121 improves the power factor of the power supply current flowing between the variable power supply 1 and the rectifier circuit 122.

[0031] Furthermore, in the configurations shown in Figures 5 and 6, it is possible to connect to general commercial single-phase AC power supplies or three-phase AC power supplies other than the variable power supply unit 1. In addition, for the power conversion devices 41 of the outdoor unit fan 35 and the indoor unit 40, the ends of the smoothing capacitors 123 in Figures 4 to 6 are connected as the bus voltages of the respective inverter circuits, and these inverter circuits supply three-phase AC power to the respective loads.

[0032] Furthermore, as shown in Figures 4 to 6, the power converter 31 does not necessarily have a voltage boosting function. In the air conditioning system 50 according to Embodiment 1, if it is desired to boost the DC voltage applied to the inverter 141, this can be achieved by boosting the output voltage of the variable power supply 1. This does not mean that the power converter 31 is not required to have a voltage boosting function.

[0033] Figure 7 shows an example of the configuration of the inverter control unit 80 when the air conditioner 3, a component of the air conditioning system 50 according to Embodiment 1, has a locked-state energization function. Locked-state energization is a control method used to prevent liquid refrigerant from accumulating in the compressor 37. When the compressor 37 is stopped, the power converter 31 applies a voltage to the windings of the compressor motor 142 that does not drive the compressor motor 142, thereby heating the inside of the compressor 37.

[0034] The inverter control unit 80 includes a normal operation mode control unit 81, a heating operation mode control unit 82, and a drive signal generation unit 83. The normal operation mode control unit 81 is a control unit corresponding to the normal operation mode, and the heating operation mode control unit 82 is a control unit corresponding to the heating operation mode.

[0035] When the air conditioner 3 is operated in normal operation mode, the inverter control unit 80 controls the inverter 141 so that the compressor motor 142 is driven to rotate. In normal operation mode, the drive signal generation unit 83 outputs a signal to the inverter 141, such as a PWM (Pulse Width Modulation) signal, which is a signal for driving the inverter 141. When the air conditioner 3 is operated in heating operation mode, the inverter control unit 80 heats the inside of the compressor 37 without driving the compressor motor 142 to rotate by flowing a DC current through the compressor motor 142 or a high-frequency current that the compressor motor 142 cannot follow. Based on the instructions of the heating operation mode control unit 82, the drive signal generation unit 83 generates a drive signal to flow a DC current through the compressor motor 142 or a drive signal to flow a high-frequency current through the compressor motor 142 and outputs it to the inverter 141. The inside of the compressor 37 is heated by the flow of DC current or high-frequency current through the compressor motor 142. As a result, the liquid refrigerant remaining in the compressor 37 is heated and vaporized, preventing the liquid refrigerant from accumulating in the compressor 37.

[0036] The inverter control unit 80 can be configured as a discrete system such as a CPU, DSP, or microcomputer. The inverter control unit 80 may also be composed of electrical circuit elements such as analog circuits or digital circuits.

[0037] Figure 8 is a flowchart illustrating the operation of the centralized control controller 2 in Embodiment 1. The centralized control controller 2 receives power estimation parameters from each air conditioner 3 (step S101) and estimates the power consumption of each air conditioner 3 based on the values ​​of the power estimation parameters (step S102).

[0038] Power estimation parameters are parameters used to estimate the power consumption of the air conditioner 3. Examples of power estimation parameters include the output voltage command value of the variable power supply 1, the output voltage, output current and carrier frequency of each power converter 31, the operating speed of the compressor 37 and outdoor unit fan 35, the opening degree of each valve in the refrigeration cycle, the temperature and pressure of each part of the refrigeration cycle, and the airflow and airflow direction of the indoor unit fan 45. In this paper, power estimation parameters are sometimes referred to as "first parameters".

[0039] Next, the centralized control controller 2 checks whether or not there is a demand response request from the variable power supply unit 1 (step S103). The demand response request may also be instructed by a control device (not shown) that is higher level than the variable power supply unit 1.

[0040] If a demand response request for increased power is received (step S104, Yes), the centralized control controller 2 determines the values ​​of the power change parameters so that the total power consumption of the air conditioners 3 increases from the current level (step S105), and transmits the determined power change parameters to the variable power supply unit 1 and each air conditioner 3 (step S106). Thereafter, the process returns to step S101 and repeats the process from step S101.

[0041] Power change parameters are parameters used to change the power consumption of at least one of the air conditioner 3 and the variable power supply unit 1. Examples of power change parameters include the output voltage command value of the variable power supply unit 1, the output voltage, output current and carrier frequency of each power converter 31, the operating speed of the compressor 37 and outdoor unit fan 35, the opening degree of each valve in the refrigeration cycle, the temperature and pressure of each part of the refrigeration cycle, and the airflow and airflow direction of the indoor unit fan 45. In this paper, power change parameters are sometimes referred to as "second parameters".

[0042] Hereinafter, specific examples of increasing the power consumption of at least one of the air conditioner 3 and the variable power supply device 1 will be described. For example, for the variable power supply device 1, the power consumption can be increased by increasing the carrier frequency of the power conversion device 11 to increase the switching loss. For each air conditioner 3, the power consumption can be increased by increasing the rotation speed command to the compressor motor 142 and the outdoor unit fan 35. Also, in the indoor unit 40, when trying to efficiently obtain comfort with less power consumption by directly blowing air on a person using a human detection sensor 47 or the like, the air conditioner 3 is operated in a direction of increasing power consumption by controlling the air direction of the indoor unit fan 45 to blow air to a place other than the person, thereby changing the temperature distribution in the air-conditioned space.

[0043] Also, when there is no up-demand response request (step S104, No), conversely, when there is a down-demand response request (step S107, Yes), the centralized management controller 2 determines the value of the power change parameter so that the power consumption of the entire air conditioner 3 decreases from the current level (step S108), and transmits the determined power change parameter to the variable power supply device 1 and each air conditioner 3 (step S106). Thereafter, the process returns to step S101, and the processing from step S101 is repeated.

[0044] Hereinafter, specific examples of decreasing the power consumption of at least one of the air conditioner 3 and the variable power supply device 1 will be described. For example, for the variable power supply device 1, the power consumption can be decreased by reducing the DC voltage command value to the power conversion device 11 and reducing the power supplied to the power conversion device 31 of the air conditioner 3. For the air conditioner 3, the power consumption can be decreased by reducing the rotation speed command to the compressor motor 142 and the outdoor unit fan 35. Also, the power consumption can be decreased by reducing the refrigerant flow rate by reducing the opening degree of the solenoid valve for adjusting the amount of refrigerant flowing in the outdoor unit heat exchanger 34 and reducing the workload of the air conditioner 3 itself.

[0045] When there is no request for either the upward demand response or the downward demand response (No in step S107), the centralized management controller 2 determines the value of the power change parameter so as to increase the efficiency of the entire air conditioner 3 (step S109), and transmits the determined power change parameter to the variable power supply device 1 and each air conditioner 3 (step S106). Thereafter, the process returns to step S101, and the processing from step S101 is repeated.

[0046] Hereinafter, a specific example of increasing the efficiency of the entire air conditioner 3 will be described. For example, in a state where the rotational speeds of the compressor motor 142 and the outdoor unit fan 35 of each air conditioner 3 are maintained, that is, in a state where the workload of the entire air conditioner 3 is maintained, the output voltage command value of the variable power supply device 1, the carrier frequency of the power conversion device 31 provided in the air conditioner 3, etc. are changed to improve the efficiency. Note that due to the characteristics of the switching elements of the power conversion device 31, as well as the characteristics of the motors of the compressor 37, the compressor motor 142, and the outdoor unit fan 35, the values of the parameters and the combinations of the parameter values at which the efficiency is maximized are different. Therefore, the values of the parameters may be determined by prior experiments, learning by AI (Artificial Intelligence), etc.

[0047] FIG. 9 is a diagram showing the relationship between the items of the power change parameter that can be changed by the control flow shown in FIG. 8 and the increase / decrease direction of its value. On the front side of FIG. 9, the items of the power change parameter are shown, and at the top of the table of FIG. 9, the increase / decrease direction of the value of the power change parameter is shown.

[0048] In Figure 9, "increasing direction" means that the power change parameter value described in the relevant section is controlled to increase, and "decreasing direction" means that the power change parameter value described in the relevant section is controlled to decrease. When the temperature of each part of the refrigeration cycle is selected as the power change parameter, during an upward demand response, the control is directed to increase the temperature difference between the highest and lowest temperature sections, and during a downward demand response, the control is directed to decrease the temperature difference between the highest and lowest temperature sections. Similarly, when the pressure of each part of the refrigeration cycle is selected as the power change parameter, during an upward demand response, the control is directed to increase the pressure difference between the highest and lowest pressure sections, and during a downward demand response, the control is directed to decrease the pressure difference between the highest and lowest pressure sections. Furthermore, when the airflow of the indoor unit fan 45 is selected as the power change parameter, during an upward demand response, the control is directed to increase the airflow, and during a downward demand response, the control is directed to decrease the airflow.

[0049] As mentioned above, the parameter values ​​and combinations that maximize efficiency vary depending on the characteristics of the switching elements, the characteristics of various motors, etc. Therefore, parameter changes are not simple and it is desirable to determine them through prior experiments or AI learning. This part is shown with hatching in Figure 9. Similarly, the output voltage command value of the variable power supply unit 1 and the carrier frequency of the power converter 11 of the air conditioner 3 are also items that are preferable to determine through prior experiments or AI learning. For this reason, these items are also shown with hatching in Figure 9.

[0050] Furthermore, although the control flow in Figure 8 does not show heating control when the air conditioner 3 has a fixed energization function, heating control may be performed alone or in combination with the control in Figure 8, especially during upward demand response. For example, during upward demand response, power consumption can be increased by performing heating control. Also, if heating control is actively performed during upward demand response, the number of times heating control is performed during efficiency improvement operation and downward demand response can be reduced, thus contributing to the requirements for efficiency improvement and downward demand response.

[0051] As described above, the air conditioning system according to Embodiment 1 comprises a variable power supply unit capable of changing the output voltage, one or more air conditioners that operate by receiving DC or AC voltage output from the variable power supply unit, and a centralized control controller that manages the variable power supply unit and the air conditioners. The variable power supply unit is configured to output at least one of DC, single-phase AC, and three-phase AC, and the variable power supply unit and the centralized control controller are configured to send and receive data to and from each other, and the air conditioners and the centralized control controller are configured to send and receive data to and from each other. According to the air conditioning system according to Embodiment 1, the variable power supply unit, the centralized control controller, and the air conditioners are configured to send and receive data to and from each other, so the centralized control controller can receive a first parameter used to estimate the power consumption of each air conditioner from each air conditioner and estimate the power consumption of the entire air conditioning system. In addition, the variable power supply unit and each air conditioner can receive a second parameter used to change the power consumption of the air conditioners from the centralized control controller. As a result, energy management such as demand response can be performed using the air conditioning system according to Embodiment 1.

[0052] In the air conditioning system according to Embodiment 1, the centralized control controller may calculate whether it is possible to increase or decrease the overall power consumption of the air conditioner by changing a second parameter. In this embodiment, communication processing is only required when it is possible to increase or decrease the overall power consumption of the air conditioner, thus preventing unnecessary communication and preventing an increase in processing load and communication resource consumption.

[0053] In the air conditioning system according to Embodiment 1, the centralized control controller can be configured to perform an upward demand response or a downward demand response operation in accordance with a demand response request from a variable power supply or a higher-level control device. In this configuration, when an upward demand response request is received, the centralized control controller can determine the value of the second parameter so as to increase the power consumption of the entire air conditioner, and when a downward demand response request is received, it can determine the value of the second parameter so as to decrease the power consumption of the entire air conditioner. Furthermore, when there is no request for an upward demand response or a downward demand response, the centralized control controller can determine the value of the second parameter so as to increase the overall efficiency of the air conditioner. According to the air conditioning system according to Embodiment 1, by changing the second parameter depending on whether or not there is a demand response request, a demand response operation linked between the variable power supply and each air conditioner can be implemented, making it possible to implement a more effective demand response operation than conventional systems while performing highly efficient operation control.

[0054] In the air conditioning system according to Embodiment 1, if the air conditioner has a heating operation mode in which the inside of the compressor is heated without rotating the compressor motor, the value of the second parameter may be determined in the heating operation mode so as to increase efficiency or heating amount. Using an air conditioning system configured in this way, power consumption can be increased by performing heating control during upward demand response. Furthermore, by actively performing heating control during upward demand response, the number of times heating control is performed during efficiency improvement operation and downward demand response can be reduced, thus contributing to the requirements for efficiency improvement and downward demand response.

[0055] Furthermore, the energy management method in an air conditioning system according to Embodiment 1 is an energy management method in an air conditioning system comprising a variable power supply device capable of changing the output voltage, one or more air conditioners that operate by receiving DC voltage or AC voltage output from the variable power supply device, and a centralized control controller that manages the air conditioners and the variable power supply device, and the method may include the following steps 1 to 4. In the first step, each air conditioner transmits a first parameter used to estimate the power consumption of the air conditioner to the centralized control controller. In the second step, the centralized control controller receives the first parameter from each air conditioner and estimates the power consumption of the entire air conditioning system. In the third step, the variable power supply device or each air conditioner receives a second parameter used to change the power consumption of the air conditioner from the centralized control controller. In the fourth step, the power consumption of the entire air conditioning system is controlled based on the second parameter received in the third step. By using this energy management method, which includes the first to fourth steps, demand response operation can be implemented by linking the variable power supply unit and each air conditioner by changing the second parameter. This makes it possible to implement more effective demand response operation than conventional methods while performing highly efficient operational control.

[0056] Embodiment 2. Embodiment 2 describes start-up control and stop-down control performed using the communication function of a centralized control controller 2 that can communicate data with the variable power supply unit 1 and the air conditioner 3.

[0057] Figure 10 is a first flowchart illustrating the operation of the centralized control controller 2 in Embodiment 2. The centralized control controller 2 checks whether there is a request for a new connection of the air conditioner 3 (step S201). As a means of checking whether there is a request for a new connection of the air conditioner 3, for example, a special command that the installer inputs to the centralized control controller 2 when connecting the air conditioner 3 for the first time may be provided. If there is a request for a new connection (step S201, Yes), the centralized control controller 2 transmits, for example, an output voltage command value in the pattern shown in Figure 11 to the variable power supply unit 1 (step S202). After transmitting the output voltage command value, the process returns to step S201 and the processing from step S201 is repeated.

[0058] Figure 11 shows a first example of a DC voltage command value used to explain the control flow shown in Figure 10. The horizontal axis in Figure 11 represents time. The key point shown in Figure 11 is to gradually increase the DC voltage command value of the variable power supply 1 as time progresses. The DC voltage command value of the variable power supply 1 is instructed by the centralized control controller 2. By gradually increasing the DC voltage command value of the variable power supply 1 as shown in Figure 11, the inrush current to the smoothing capacitor 123 of the air conditioner 3 can be suppressed. If the air conditioner 3 is of the type that is connected to a conventional commercial power supply, the air conditioner 3 is equipped with a resistor, relay circuit, etc. for preventing inrush current. On the other hand, according to Embodiment 2, in which the centralized control controller 2 controls the DC voltage command value of the variable power supply 1, the inrush current to the smoothing capacitor 123 of the air conditioner 3 can be suppressed without using functions such as a resistor, relay circuit, etc. for preventing inrush current.

[0059] In Figure 11, the slope of the straight line A, which gradually increases the DC voltage command value over time, can be determined so that the current i flowing through the smoothing capacitor 123 does not exceed the overcurrent cutoff value of the air conditioner 3. Here, the current i flowing through the smoothing capacitor 123 can be expressed as shown in equation (1) below.

[0060]

[0061] In equation (1) above, E is the DC voltage command value of the variable power supply 1, R is the resistance component of the reactor 121 and smoothing capacitor 123 of the air conditioner 3, L is the inductance component of the reactor 121, and C is the capacitance component of the smoothing capacitor 123. Furthermore, α is the time constant in the LCR series circuit when the air conditioner 3 is considered as an LCR series circuit with resistance component R, inductance component L, and capacitance component C, and ω ０ α is the resonant frequency in an LCR series circuit. These are the time constant α and the resonant frequency ω. ０ As per the proviso in equation (1), α = R / 2L, ω ０ It can be expressed as = 1 / (√LC).

[0062] When viewed from the variable power supply unit 1, the circuit constants of the air conditioner 3 are: resistance component R, inductance component L, capacitance component C, time constant α, and resonant frequency ω. ０ This is uniquely determined. Therefore, the current i flowing through the smoothing capacitor 123 is expressed by one of the three conditions shown in parentheses in equation (1) above. The slope of the straight line A shown in Figure 11 should be determined so that the current i expressed by the corresponding equation does not exceed the overcurrent cutoff value of the air conditioner 3.

[0063] Returning to the control flow in Figure 10, if there is no new connection request for the air conditioner 3 in step S201 (step S201, No), the centralized control controller 2 checks whether there is a request to start the air conditioner 3 (step S203). If there is a start request (step S203, Yes), the centralized control controller 2 sends an output voltage command value to the variable power supply unit 1, for example, in the pattern shown in Figure 12 (step S204). After sending the output voltage command value, the process returns to step S201, and the processing from step S201 is repeated.

[0064] Figure 12 shows a second example of the DC voltage command value used to explain the control flow shown in Figure 10. The horizontal axis in Figure 12 represents the rotational speed. The key point shown in Figure 12 is that the DC voltage command value of the variable power supply 1 is gradually increased in accordance with the rotational speed. The DC voltage command value of the variable power supply 1 is instructed by the centralized control controller 2. As shown in Figure 12, by gradually increasing the DC voltage command value of the variable power supply 1 in accordance with the rotational speed, the accuracy of current detection can be improved when the air conditioner 3 is started up, and the starting up of the air conditioner 3 becomes easier. The reason for obtaining this effect is as follows.

[0065] We consider motor control using a single-shunt current detection method in which a shunt resistor or current sensor is mounted on the busbar connecting the smoothing capacitor 123 and the inverter 141. Here, as shown in Figure 12, if the DC voltage command value of the variable power supply 1 is gradually increased according to the rotational speed of the compressor motor 142 or the outdoor unit fan 35, the magnitude of the starting current can be limited compared to when connecting commercial power or a DC power supply with a fixed voltage amplitude. As a result, the pulse width for current detection can be widened during startup, making it possible to improve the accuracy of current detection. Naturally, if the accuracy of current detection can be improved, it will become easier to start the air conditioner 3.

[0066] In Figure 12, the DC voltage command value when the rotational speed is zero, that is, the initial value when starting up the DC voltage command value, is the final value of the DC voltage command value shown in Figure 11, and the DC voltage command value should be increased in proportion to the induced voltage generated in the compressor motor 142 or the outdoor unit fan 35 motor. In this way, the current that flows when the air conditioner 3 is started up can be made smaller.

[0067] Returning to the control flow in Figure 10, in step S203, if there are no start requests from any of the air conditioners 3 in the air conditioning system 50 (step S203, No), the centralized control controller 2 sends an output voltage command value of zero to the variable power supply unit 1 (step S205). Upon receiving the output voltage command value of zero, the variable power supply unit 1 controls the switch 12 to an open state by, for example, setting the connection destination of the output terminal 17 of the switch 12 in Figure 1 to the open terminal 16. After controlling the switch 12 to an open state, the process returns to step S201 and repeats the process from step S201.

[0068] Figure 13 is a second flowchart illustrating the operation of the centralized control controller 2 in Embodiment 2. The centralized control controller 2 checks whether there is a request to stop the air conditioner 3 (step S301). If there is a request to stop (step S301, Yes), the centralized control controller 2 transmits an output voltage command value to the variable power supply unit 1, for example, in the pattern shown in Figure 14 (step S302). After transmitting the output voltage command value, the process returns to step S301, and the processing from step S301 is repeated.

[0069] Figure 14 is a diagram illustrating an example of a DC voltage command value used to explain the control flow shown in Figure 13. The horizontal axis in the upper and lower parts of Figure 14 represents time. The upper part of Figure 14 shows the DC voltage command value of the variable power supply unit 1. The lower part of Figure 14 shows the change in rotational speed of the compressor motor 142 or the outdoor unit fan 35 when the compressor motor 142 or the outdoor unit fan 35 is controlled by the DC voltage command value shown in the upper part of Figure 14. The key point shown in Figure 14 is to gradually decrease the DC voltage command value of the variable power supply unit 1 over time. The DC voltage command value of the variable power supply unit 1 is instructed by the centralized control controller 2. By gradually decreasing the DC voltage command value of the variable power supply unit 1 as shown in Figure 14, it is possible to suppress the phenomenon in which the bus voltage of the power converter 31 rises sharply due to the regenerative energy of the compressor motor 142 or the outdoor unit fan 35 when the air conditioner 3 is stopped.

[0070] In Figure 14, the initial value for lowering the DC voltage command value is the final value of the DC voltage command value shown in Figure 11, and the DC voltage command value should be reduced in proportion to the induced voltage generated in the compressor motor 142 or the outdoor unit fan 35. In this way, the compressor motor 142 or the outdoor unit fan 35 can be stopped with the bus voltage of the power converter 31 reduced, making it possible to reduce the overvoltage that may occur when the air conditioner 3 is stopped.

[0071] Furthermore, if the rotational speed of the compressor motor 142 or the outdoor unit fan 35 falls below a rotational speed that prevents the bus voltage of the power converter 31 from becoming overvoltage due to the regenerative power generated by the rotation of the compressor motor 142 or the outdoor unit fan 35, the rotational speed of the compressor motor 142 or the outdoor unit fan 35 may be reduced to zero in a stepwise manner, as shown in the lower diagram of Figure 14.

[0072] Returning to the control flow in Figure 13, if no stop request is received for any of the air conditioners 3 in the air conditioning system 50 in step S301 (step S301, No), the air conditioners 3 continue to operate (step S303). Subsequently, the process returns to step S301 and repeats the process from step S301.

[0073] As described above, according to the air conditioning system of Embodiment 2, when the air conditioner is connected to the variable power supply, or when the compressor or outdoor fan of the air conditioner is started, the central control controller provides the variable power supply with an output voltage command value such that the output voltage of the variable power supply gradually increases from a low state. This makes it possible to suppress the inrush current to the smoothing capacitor of the air conditioner without using functions such as resistors and relay circuits for inrush current prevention that are provided in conventional air conditioners connected to commercial power. Therefore, by using the air conditioning system of Embodiment 2, it is possible to pursue a configuration that omits resistors and relay circuits for inrush current prevention, and if resistors and relay circuits for inrush current prevention can be omitted, a great effect can be obtained in that the air conditioner can be constructed at a low cost. Furthermore, even if resistors and relay circuits for inrush current prevention cannot be omitted, the performance of these circuit components can be reduced, which contributes to lowering the cost of the air conditioner.

[0074] Furthermore, according to the air conditioning system of Embodiment 2, when the air conditioner stops, the centralized control controller provides the variable power supply with an output voltage command value such that the output voltage of the variable power supply gradually decreases from a high state. This suppresses the phenomenon in which the bus voltage of the power converter rises sharply due to the regenerative energy of the compressor motor or outdoor unit fan when the air conditioner stops, and makes it possible to reduce the overvoltage that may occur when the air conditioner stops. Therefore, by using the air conditioning system of Embodiment 2, the risk of damage to circuit components due to overvoltage that may occur when the air conditioner stops can be reduced, thus contributing to improved reliability of the air conditioning system.

[0075] The configurations shown in the above embodiments are examples only, and it is possible to combine them with other known technologies, combine different embodiments, and omit or modify parts of the configuration without departing from the gist of the invention.

[0076] 1 Variable power supply unit, 2 Centralized control controller, 3, 3a-3c Air conditioner, 10, 20, 32, 32a-32c External communication equipment, 11, 11a-11c, 31, 31a-31c, 41 Power converter, 12 Switch, 13 DC terminal, 14 Single-phase AC terminal, 15 Three-phase AC terminal, 16 Open terminal, 17 Output terminal, 30 Outdoor unit, 33 Outdoor unit control unit, 34 Outdoor unit heat exchanger, 35 Outdoor unit fan, 36 Outdoor unit communication device, 37 Compressor, 40 Indoor unit, 43 Indoor unit control unit, 44 Indoor unit heat exchanger, 45 Indoor unit fan, 46 Indoor unit communication device, 47 Human detection sensor, 48 Wind direction adjustment means, 50 Air conditioning system, 52 AC power supply, 54 Renewable energy, 70 Power receiving terminal, 80 Inverter control unit, 81 Normal operation mode control unit, 82 Heating operation mode control unit, 83 Drive signal generation unit, 91 Processor, 92 Memory, 93 Storage device, 121 Reactor, 122 Rectifier circuit, 123 Smoothing capacitor, 141 Inverter, 142 Compressor motor, 152a-152f Diodes, 156a-156f Switching elements.

Claims

1. An air conditioning system comprising: a variable power supply that can change the output voltage; one or more air conditioners that operate by receiving a DC voltage or AC voltage output from the variable power supply; and a centralized control controller that manages the variable power supply and the air conditioners, wherein the variable power supply is configured to output at least one of DC, single-phase AC, and three-phase AC; the variable power supply and the centralized control controller are configured to send and receive data to and from each other; and the air conditioners and the centralized control controller are configured to send and receive data to and from each other.

2. The air conditioning system according to claim 1, wherein the centralized control controller receives a first parameter used to estimate the power consumption of each air conditioner from each air conditioner to estimate the power consumption of the entire air conditioning system.

3. The air conditioning system according to claim 1 or 2, wherein the variable power supply and each of the air conditioners receive a second parameter from the central control controller used to change the power consumption of the air conditioners.

4. The air conditioning system according to claim 3, wherein the centralized control controller calculates whether it is possible to increase or decrease the power consumption of the entire air conditioner by changing the second parameter.

5. The air conditioning system according to claim 3 or 4, wherein the centralized control controller performs an upward demand response or downward demand response operation in accordance with a demand response request from the variable power supply unit or a higher-level control unit.

6. The air conditioning system according to claim 5, wherein the centralized control controller determines the value of the second parameter so as to increase the power consumption of the entire air conditioner when a request for an upward demand response is made, and determines the value of the second parameter so as to decrease the power consumption of the entire air conditioner when a request for a downward demand response is made.

7. The air conditioning system according to claim 5 or 6, wherein the centralized control controller determines the value of the second parameter so as to increase the overall efficiency of the air conditioner when there is no request for an upward demand response or a downward demand response.

8. The air conditioning system according to any one of claims 3 to 7, wherein the air conditioner has a heating operation mode that heats the inside of the compressor without rotating the compressor motor, and in the heating operation mode, the value of the second parameter is determined so as to increase efficiency or heating amount.

9. The air conditioning system according to any one of claims 1 to 8, wherein the centralized control controller provides the variable power supply with an output voltage command value such that the output voltage of the variable power supply gradually increases from a low state when the air conditioner is connected to the variable power supply, or when the compressor or outdoor fan of the air conditioner is started.

10. The air conditioning system according to any one of claims 1 to 9, wherein the centralized control controller provides the variable power supply with an output voltage command value such that the output voltage of the variable power supply gradually decreases from a high state when the air conditioner stops.

11. An energy management method for an air conditioning system comprising a variable power supply capable of changing the output voltage, one or more air conditioners that operate by receiving a DC voltage or AC voltage output from the variable power supply, and a centralized control controller that manages the air conditioners and the variable power supply, the method comprising: a first step of each of the air conditioners transmitting a first parameter used by each air conditioner to estimate the power consumption of the air conditioner to the centralized control controller; a second step of the centralized control controller receiving the first parameter from each of the air conditioners and estimating the power consumption of the entire air conditioning system; a third step of the variable power supply or each of the air conditioners receiving a second parameter used by each air conditioner to change the power consumption of the air conditioner from the centralized control controller; and a fourth step of controlling the power consumption of the entire air conditioning system based on the second parameter received in the third step.

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