Outdoor unit of an air conditioning system

Abstract

To suppress the flow of rush current into a transformer which adjusts a load voltage.SOLUTION: Output power from a power generator 11 is supplied to a load via the transformer which adjusts a load voltage as a voltage to be output to the load. When switching power supply changeover switches 52, 352 from a commercial power supply 36 to the output power, a power control device 33 controls an inverter part 72a to control a voltage value Vout for the output power to be a threshold value voltage value VT1 or lower. Besides, after a predetermined time PD passes from a time T1 when switching from the commercial power supply 36 to the output power, the power control device 33 controls the inverter part 72a to control the voltage value Vout for the output power so that the voltage value Vout for the output power becomes a predetermined voltage value VA set according to the load.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] The present disclosure relates to an outdoor unit of an air conditioner.

Background Art

[0002] Patent Document 1 discloses an outdoor unit of an air conditioner including a gas engine that drives a compressor, a generator driven by the gas engine, an inverter, and a power supply switching board that switches between a commercial power supply and a self - operating circuit.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present invention provides an outdoor unit of an air conditioner that can suppress an inrush current flowing into a transformer that adjusts a load voltage, which is a voltage output to a load.

Means for Solving the Problems

[0005] The present disclosure is an outdoor unit of an air conditioner including a compressor, a gas engine that drives the compressor, a generator driven by the gas engine, and an inverter, and a power control device that controls output power from the generator. The output power is supplied to the load through a transformer that adjusts a load voltage, which is a voltage output to the load. When switching from a commercial power supply to the output power, the power control device controls the inverter to control the voltage value of the output power to be less than or equal to a threshold voltage value. After a lapse of a predetermined time from the time of switching from the commercial power supply to the output power, the power control device controls the inverter so that the voltage value of the output power becomes a predetermined voltage value set according to the load, thereby controlling the voltage value of the output power. [Effects of the Invention]

[0006] The present invention provides an outdoor unit for an air conditioner that can suppress the inrush current flowing into the transformer. [Brief explanation of the drawing]

[0007] [Figure 1] This diagram schematically shows the power system of an air conditioning system during normal operation according to an embodiment of the present disclosure. [Figure 2] A schematic diagram showing the power system of an air conditioning system during normal operation (non-power outage). [Figure 3] A block diagram schematically showing the configuration of a power control device. [Figure 4] A schematic diagram showing the wiring of a power control device. [Figure 5] A schematic diagram showing the power grid of an air conditioning system during a power outage. [Figure 6] A flowchart illustrating the first operation of the power control device. [Figure 7] A graph showing an example of the voltage value of AC power output from a power control device. [Figure 8] A flowchart illustrating a second example of the operation of the power control device. [Figure 9] A flowchart illustrating another example of the second operation of the power control device. [Modes for carrying out the invention]

[0008] (Knowledge and other information that formed the basis of this disclosure) At the time the inventors conceived this disclosure, there was a technology to realize an air conditioning system that could reliably supply power to desired air conditioning equipment using power generated by an engine during power outages, etc. This air conditioning system comprises an outdoor unit equipped with a gas engine that drives a compressor, a generator driven by the gas engine, and an inverter that outputs the power generated by the generator to the commercial power supply, and a power switching panel that switches between the commercial power supply and an independent operation circuit. This air conditioning system connects a load including an indoor unit to this power switching panel, and enables independent operation of the outdoor unit and the load connected to the power switching panel using power generated during power outages, etc.

[0009] In the outdoor units of such air conditioning systems, a transformer is located in the power transfer panel to adjust the load voltage, which is the voltage output to the load. Furthermore, when switching from commercial power to the standalone operation circuit during a power outage, there is a possibility of inrush current flowing from the inverter to the transformer. This inrush current could potentially damage the transformer and other circuits.

[0010] Thus, the inventors discovered a problem with conventional configurations: the possibility of inrush current flowing into the transformer located in the power transfer panel. To solve this problem, they arrived at the subject matter of this disclosure.

[0011] Therefore, this disclosure provides an outdoor unit for an air conditioning system that can suppress the inrush current flowing into the transformer.

[0012] The embodiments will be described in detail below with reference to the drawings. However, unnecessary details may be omitted. For example, detailed explanations of already well-known matters or redundant explanations of substantially identical configurations may be omitted. This is to avoid the following explanation becoming unnecessarily verbose and to facilitate understanding for those skilled in the art. The attached drawings and the following description are provided to enable those skilled in the art to fully understand this disclosure and are not intended to limit the subject matter described in the claims.

[0013] (Embodiment) Hereinafter, embodiments will be described with reference to FIGS. 1 to 9. [1. Configuration] [1-1. Configuration of the air conditioning system]

[0014] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0015] Hereinafter, embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram schematically showing the power system of the air conditioning system 1 according to an embodiment of the present invention. FIG. 1 shows the air conditioning system 1 during normal operation (normal operation mode). In FIG. 1, the power lines through which power flows are shown in thick lines. The air conditioning system 1 is a system installed in facilities such as large buildings and schools, and functions as a plurality of (four in this embodiment) air conditioning devices 1A to 1D. The air conditioning system 1 includes a plurality of (four in this embodiment) outdoor units 2A, 2B, 2C, and 2D installed outdoors. In the start-up control during a power outage of the commercial power supply 36 or the like, in the air conditioning system 1 of the present disclosure, a predetermined one outdoor unit 2A operates as a master unit. Further, according to the control of the outdoor unit 2A which is the master unit, the remaining outdoor units 2B, 2C, and 2D operate as slave units.

[0016] Indoor unit groups 3A to 3D installed in a predetermined area indoors are connected to each of the outdoor units 2A to 2D to form independent refrigeration cycle circuits, and air conditioning operations are respectively performed within each refrigeration cycle. Each of the indoor unit groups 3A to 3D includes a plurality of (four in this embodiment) indoor units 13a to 13d. The number of these indoor units can be appropriately changed according to the size of the air conditioning target area and the capacity of the outdoor unit. The air conditioner 1A includes an outdoor unit 2A and indoor units 13a to 13d of the indoor unit group 3A. The air conditioner 1B includes an outdoor unit 2B and indoor units 13a to 13d of the indoor unit group 3B. The air conditioner 1C includes an outdoor unit 2C and indoor units 13a to 13d of the indoor unit group 3C. The air conditioner 1D includes an outdoor unit 2D and indoor units 13a to 13d of the indoor unit group 3D.

[0017] The air conditioning system 1 includes a single power switchboard 50 that switches between a commercial power supply 36, which is a commercial AC power supply, and the system of the generated power generated by the generators 11 provided in each of the outdoor units 2A to 2D. The power switchboard 50 is connected to the outdoor units 2A to 2D and the indoor unit groups 3A to 3D. Further, the power switchboard 50 is connected to a lighting device 38 provided in the area where each of the indoor units 13a to 13d of the indoor unit groups 3A to 3D is installed. Further, the power switchboard 50 is connected to a power outlet 60 provided in the area where each of the indoor units 13a to 13d of the indoor unit groups 3A to 3D is installed. The power switchboard 50 is provided with a power switch 52 and a power switch 352 that switch between the commercial power supply 36 and the system of the generated power generated by the generators 11 of the outdoor units 2A to 2D. The power switchboard 50 is provided on the downstream side of the breaker 37 in the upstream power supply line 51a (FIG. 2). The power switch 52 and the power switch 352 correspond to an example of a "switching switch". The power switchboard 50 corresponds to an example of a "switchboard".

[0018] In the present embodiment, the case where each of the outdoor units 2A to 2D includes one generator 11 will be described, but the present invention is not limited to this. At least one of the outdoor units 2A to 2D may include a plurality of generators 11. The plurality of units may be two units or three or more units.

[0019] [1-2. Configuration of Air Conditioner] Next, we will explain the outdoor units 2A to 2D, and the indoor unit groups 3A to 3D. Figure 2 is a circuit diagram showing the outdoor unit 2A and indoor unit group 3A, which operate as the master unit. In Figure 2, the lines to which power is supplied are shown with thick lines. The outdoor unit 2A and the indoor unit group 3A are connected by inter-unit piping 4 consisting of liquid pipe 4a and gas pipe 4b, thereby forming a refrigeration cycle circuit for performing air conditioning operation in the air conditioning system 1. The outdoor unit 2A houses a gas engine 10 that functions as a power source, a generator 11 that generates electricity using the driving force of the gas engine 10, and a compressor 12 that compresses the refrigerant using the driving force of the gas engine 10. The gas engine 10 generates driving force by burning a mixture of fuel, such as gas supplied through the fuel control valve 7, and air supplied through the throttle valve 8. The fuel control valve 7 and the throttle valve 8 in this embodiment are so-called solenoid valves that are driven by DC power.

[0020] The indoor unit group 3A comprises multiple indoor units 13a to 13d (four in this embodiment) that are distributed and installed at various locations within the same facility. Each of the indoor units 13a to 13d is provided with a remote control 5 for operating it, and when power is supplied to the indoor units 13a to 13d, individual operation such as starting and stopping can be performed in response to user operations on the remote control 5.

[0021] The compressor 12 is connected to the gas engine 10. A four-way valve 15 and an outdoor heat exchanger 17 are connected in order to the discharge pipe 12c of the compressor 12. The outdoor heat exchanger 17 is equipped with a blower 26 driven by a DC motor, which is a fan motor 26a. The outdoor heat exchanger 17 is connected via liquid pipe 4a to expansion valves 19a to 19d, which are pressure reducing devices for indoor units 13a to 13d, and to indoor heat exchangers 21a to 21d. A four-way valve 15 is connected to indoor heat exchangers 21a to 21d via gas pipe 4b, and the compressor 12 is connected to this four-way valve 15 via the suction pipe 12d of the compressor 12. In this embodiment, the four-way valve 15 is a so-called solenoid valve driven by DC power. Each of the indoor heat exchangers 21a to 21d is provided with a blower 6a to 6d, which is driven by a DC motor.

[0022] When the compressor 12 is driven, if the four-way valve 15 is switched to the heating state, the refrigerant circulates in the following order, as shown by the solid arrows in Figure 2: compressor 12, four-way valve 15, indoor heat exchangers 21a to 21d, expansion valves 19a to 19d, and outdoor heat exchanger 17. The room is then heated by the heat of condensation of the refrigerant in the indoor heat exchangers 21a to 21d. Conversely, if the four-way valve 15 is switched to the cooling state, the refrigerant circulates in the following order, as shown by the dashed arrows in Figure 2: compressor 12, four-way valve 15, outdoor heat exchanger 17, expansion valves 19a to 19d, and indoor heat exchangers 21a to 21d. The room is then cooled by the heat of evaporation of the refrigerant in the indoor heat exchangers 21a to 21d. Furthermore, since indoor units 13a to 13d are connected in parallel, refrigerant can be supplied individually to each of them, and each of them can be operated independently.

[0023] Next, we will describe the cooling system for the gas engine 10. The gas engine 10 is a so-called water-cooled engine, cooled by coolant supplied by a coolant pump 27. The coolant pump 27 is equipped with a pump motor 27a that drives the coolant pump 27. The pump motor 27a is a DC motor. The gas engine 10 is cooled by the circulation of cooling water, which is supplied by the cooling water pump 27, through the water jacket of the gas engine 10.

[0024] [1-3. Power system] Next, I will explain the power grid. As shown in Figure 1, in the air conditioning system 1 of this embodiment, each generator 11 of outdoor units 2A to 2D is connected to the commercial power supply 36, which is the power grid of the electric power company. This makes it possible to supply the power generated by the generators 11, along with the power from the commercial power supply 36, to the outdoor units 2A to 2D, indoor units 13a to 13d, lighting device 38, and outlet 60. In this case, outdoor units 2A to 2D and indoor units 13a to 13d correspond to the self-consumed power load of the air conditioning system 1. The power supplied to the lighting device 38 and the outlet 60 corresponds to other power loads unrelated to air conditioning.

[0025] The power transfer panel 50 includes a power transfer switch 52 installed in parallel with the upstream power supply line 51a, which is a commercial power line. In this embodiment, the power transfer switch 52 is connected to the master outdoor unit 2A and the slave outdoor units 2B, 2C, and 2D. The downstream power transfer switch 352 is connected to the indoor units 13a to 13d, the lighting device 38, and the outlet 60 via the downstream power supply line 51b.

[0026] The power selector switch 52 includes a first terminal 52a (terminal for normal operation) to which the upstream power supply line 51a is connected, a second terminal 52b (terminal for standalone operation) to which the power line 34b supplied by the generator 11 of the outdoor unit 2A is connected, and a third terminal 52c (terminal for power supply) to which the power line 34a of the commercial power supply 36 is connected. The power selector switch 52 functions as a switch circuit that switches the connection destination of the third terminal 52c to either the first terminal 52a or the second terminal 52b.

[0027] The power line 34a includes a power branch line 34a1 that branches off between the third terminal 52c and the power control device 33 of the outdoor unit 2A. The power branch line 34a1 is further branched into four, each connected to the power control device 33 of the outdoor units 2B to 2D, and to the power changeover switch 352 located at the furthest downstream. Therefore, in the air conditioning system 1, by connecting the third terminal 52c and the first terminal 52a, commercial power (200V AC power in this embodiment) can be supplied from the commercial power supply 36 to the respective power control devices 33 of outdoor units 2A to 2D. Furthermore, in the air conditioning system 1, by connecting the third terminal 52c and the second terminal 52b, the power generated by the generator 11 of outdoor unit 2A can be supplied to the power branch line 34a1. In addition, other power selector switches or on / off switches such as relays may be provided on the power branch line 34a1.

[0028] The downstream power selector switch 352 includes a first terminal 352a (terminal for normal operation) to which the upstream power supply line 51a is connected, a second terminal 352b (terminal for independent operation) to which the power branch line 34a1 supplied with power from the generator 11 of the outdoor unit 2A is connected, and a third terminal 352c (power supply terminal) to which the downstream power supply line 51b to which indoor units 13a to 13d, lighting equipment 38, and outlets 60 are connected is connected. The power selector switch 352 functions as a switch circuit that switches the connection destination of the third terminal 352c to either the first terminal 352a or the second terminal 352b.

[0029] Thus, the power transfer panel 50, equipped with a power transfer switch 52, functions as a switching means for switching the power source to the downstream power supply line 51b between the commercial power supply 36 and the power generation system (also called the power generation system). Therefore, the air conditioning system 1 can selectively perform normal operation, which uses power supplied from the commercial power supply 36 and the generators 11 of each of the outdoor units 2A to 2D to drive the outdoor units 2A to 2D, indoor units 13a to 13d, lighting equipment 38, and outlet 60, and independent operation, which disconnects from the commercial power supply 36 and drives the outdoor units 2A to 2D, indoor units 13a to 13d, lighting equipment 38, and outlet 60 using the power generated by the generators 11 of each of the outdoor units 2A to 2D.

[0030] Next, I will explain the power generation grid. As shown in Figure 2, the outdoor unit 2A, which functions as the master unit, is equipped with a power control device 33 that converts the power generated by the generator 11 and a battery 49 that stores a portion of the power generated. The power generated by the generator 11 is output to the power control device 33 via the power line 32. The power control device 33 converts the three-phase AC power generated by the generator 11 into DC power, and then converts it back into, for example, 200V AC power and outputs it to the power line 34 (generated power output line). The power line 34 branches into the power line 34a for normal operation and the power line 34b for standalone operation. Power lines 34a and 34b are connected to the first terminal 52a and the second terminal 52b of the power changeover switch 52, respectively. The power line 34a for normal operation is also connected to the outdoor controller 39 via the power line 41, and can supply power to the outdoor unit 2A, including the outdoor controller 39. Furthermore, a portion of the generated power is supplied to the battery 49 via the power line 47b shown in Figure 1, and the generated power is stored in the battery 49.

[0031] The power line 34b for independent operation is connected to the second terminal 52b of the power changeover switch 52 described above. Therefore, as described above, by connecting the second terminal 52b and the third terminal 52c of the power changeover switch 52, the generated power can be directly supplied to the power branch line 34a1 via the power changeover switch 52.

[0032] The power control device 33 is connected to the outdoor controller 39 of the outdoor unit 2A via a communication line 40 so that it can communicate with it. As described above, the outdoor controller 39 can be supplied with generated power via the power line 34a for normal operation, and can also obtain operating power from the commercial power supply 36 via the power line 41. The outdoor controller 39 functions as a control unit that centrally controls the operation of each component of the outdoor unit 2A (for example, the gas engine 10, battery 49, and power switching panel 50, etc.). Furthermore, since the outdoor unit 2A functions as a master unit, the outdoor controller 39 of this outdoor unit 2A becomes the main controller for starting up outdoor units 2A to 2D in the event of a power outage or the like. The outdoor controller 39 is connected to the indoor controller of the indoor unit group 3A via a communication line 42, enabling communication between them.

[0033] The outdoor controller 39 includes an outdoor unit control board 39c. Power from the battery 49 is supplied directly to the outdoor unit control board 39c via a power line 54. The outdoor unit control board 39c includes a processor 39a and memory 39b.

[0034] The processor 39a is a processor such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). The processor 39a functions as the autonomous control unit (startup control unit) of the outdoor unit 2A by reading and executing control programs stored in the memory 39b.

[0035] Memory 39b is a storage unit that stores various data such as control programs. Memory 39b stores data to be processed by the control program and processor 39a. Memory 39b has a non-volatile storage area. Alternatively, memory 39b may also have a volatile storage area and constitute the work area of ​​processor 39a.

[0036] The outdoor controller 39 includes an electric unit control board 20. The electric unit control board 20 can supply power via the power line 20a to each of the electric units (for example, the fan motor 26a, the pump motor 27a, the motors of various solenoid valves, etc.) in the outdoor unit 2A that are driven by DC power. This electric unit control board 20 controls the driving of the electric units that are driven by DC power.

[0037] The outdoor controller 39 controls the operation mode to switch between two modes: a normal operation mode in which the outdoor unit 2A, indoor unit group 3A, and lighting device 38 are driven by power supplied from the commercial power supply 36 and the outdoor unit 2A generator 11; and an independent operation mode in which the outdoor unit 2A, indoor unit group 3A, and lighting device 38 are driven by power generated by the generator 11 when disconnected from the commercial power supply 36 during a power outage, etc. Here, "during a power outage, etc." refers to a situation where power is not supplied from the commercial power supply 36. The outdoor controller 39 is connected to a self-contained operation switch 56, which is a manual switch operated manually by the user. In the air conditioning system 1, when the self-contained operation switch 56 is operated, the outdoor controller 39 starts the operation to switch to self-contained operation mode.

[0038] The starter motor of the gas engine 10 is connected to the power line 54, which is supplied with power from the battery 49, via the power line 48 (Figure 2). In the air conditioning system 1, the starter motor is driven with power from the battery 49 according to the control of the outdoor controller 39, and the gas engine 10 is started.

[0039] Since outdoor unit 2A functions as the master unit, its outdoor controller 39 becomes the main controller for starting up outdoor units 2A to 2D in the event of a power outage or other issues. The outdoor controller 39 of outdoor unit 2A is connected via communication lines to the respective outdoor controllers 39 of the slave outdoor units 2B to 2D.

[0040] Outdoor units 2B to 2D, which operate as slave units, have the same configuration as outdoor unit 2A, which operates as a master unit. As shown in Figure 1, outdoor units 2B to 2D differ from outdoor unit 2A in that they do not have a battery 49, a self-contained operation changeover switch 56, and a self-contained operation power line 34b output from the power control device 33.

[0041] [1-4. Configuration of the Power Control Device] Next, the power control device 33 will be described. Figure 3 is a schematic block diagram showing the configuration of the power control device 33. In Figure 3, the lines to which power is supplied are shown as thick lines. As described above, the power control device 33 is a device that converts the three-phase AC power generated by the generator 11 into DC power, and then converts it back into, for example, 200V AC power and outputs it to the power line 34 (generated power output line). The power control device 33 comprises a three-phase full-wave rectifier diode 70, an IPM (Intelligent Power Module) board 72, a filter board 74, and an inverter control board 78. The three-phase full-wave rectifier diode 70 converts the AC voltage of the AC power sent from the generator 11 via the power line 34b into a DC voltage and rectifies it. The power rectified by the three-phase full-wave rectifier diode 70 is sent to the IPM board 72 via the power line 71.

[0042] An electrolytic capacitor 80 is provided on the power line 71. The electrolytic capacitor 80 holds the DC voltage rectified by the three-phase full-wave rectifier diode 70. A DC reactor 82 is provided in the power line 71. The DC reactor 82 is a coil element necessary for boosting the DC voltage held in the electrolytic capacitor 80.

[0043] The IPM substrate 72 is a substrate on which an intelligent power module, which is a semiconductor element, is mounted. The IPM substrate 72 comprises an inverter section 72a and a converter section 72b. The inverter unit 72a, when the air conditioning system 1 is operating independently, takes the DC voltage rectified by the three-phase full-wave rectifier diode 70, boosts it to AC, converts it to AC, and supplies it to the power load as AC power maintained at a constant AC voltage. In this embodiment, the inverter unit 72a of the master outdoor unit 2A outputs AC power maintained at a constant AC voltage. In the slave outdoor units 2B to 2D, the inverter unit 72a generates a variable AC current based on the AC voltage output from the master outdoor unit 2A, according to the instructions of the master outdoor unit 2A, and outputs it as AC power.

[0044] The power supplied from the inverter unit 72a is sent to the power lines 34a and 34b via the power line 73. This power is supplied to power loads such as outdoor units 2A to 2D, indoor units 13a to 13d, lighting equipment 38, and outlets 60. The inverter unit 72a stops operating when the air conditioning system 1 is in normal operation. The inverter section 72a corresponds to an example of an "inverter".

[0045] The AC reactor 111 and the current sensor 112 are connected to the power line 73. The AC reactor 111 suppresses the harmonic currents sent out from the inverter section 72a. The current sensor 112 is connected to the inverter control board 78 via a signal line 116. This allows the inverter control board 78 to acquire the current value from the current sensor 112. In the power line 73, a filter board 74 on which a noise filter 75, which is a filter circuit, is mounted is connected downstream of the current sensor 112. The power sent from the inverter unit 72a is sent to the power line 34b via the filter board 74.

[0046] A voltage sensor 114 is provided downstream of the filter board 74 on the power line 34b. This voltage sensor 114 detects the voltage value of the AC power on the power line 34b. The voltage sensor 114 is connected to the inverter control board 78 via a signal line 120. This allows the inverter control board 78 to acquire the voltage value detected by the voltage sensor 114.

[0047] The converter unit 72b boosts the DC voltage rectified by the three-phase full-wave rectifier diode 70 and maintains it at a constant DC voltage, which is then sent to the motor control board 20 via the power line 55 as DC power. The DC power sent from the converter unit 72b is supplied to the motors of the outdoor unit 2, such as the fan motor 26a of the blower 26 and the pump motor 27a of the cooling water pump 27, via the motor control board 20 and the power line 20a, etc.

[0048] An electrolytic capacitor 118 is provided on the power line 55. The electrolytic capacitor 118 holds a voltage that has been boosted by a circuit using a DC reactor 82 and the converter section 72b of the IPM board 72, based on the DC voltage rectified by the three-phase full-wave rectifier diode 70.

[0049] The power line 34b connects the inverter unit 72a to the second terminal 52b of the power transfer panel 50. A transformer 57 is placed between the inverter unit 72a and the second terminal 52b of the power transfer panel 50. In other words, the output power of the voltage value Vout sent from the filter board 74 is supplied to the second terminal 52b via the transformer 57. The transformer 57 adjusts the load voltage value Vd, which is the voltage value of the load voltage output to the indoor units 13a to 13d, the lighting device 38, and the outlet 60. In other words, the transformer 57 adjusts the voltage value Vout of the output power sent from the filter board 74 to the load voltage value Vd. In this embodiment, the transformer 57 is controlled by the inverter control board 78 of the power control device 33. The voltage value Vout is, for example, 200V, and the load voltage value Vd is either 200V or 100V. That is, the transformer 57 switches the load voltage value Vd between 200V and 100V by the inverter control board 78 of the power control device 33. Indoor units 13a to 13d, lighting device 38, and outlet 60 correspond to an example of a "load".

[0050] Figure 4 is a schematic diagram showing the wiring in the power control device 33. As shown in Figure 4, two power lines 73 and two power lines 55 are drawn from the IPM board 72. Both power lines 55 are connected to the inverter control board 78. Two branch lines 55a and 55b are drawn from one of the two power lines 55. Branch line 55a is connected to the inverter control board 78, and branch line 55b is connected to the motor control board 20. This allows the power control device 33 to send the DC power output from the converter unit 72b to the motor unit control board 20.

[0051] In this way, the air conditioning system 1 can send the DC power converted by the power control device 33 to the motor unit of the outdoor unit 2 without converting it to AC power. Therefore, for example, the motor unit control board 20 does not need to perform power conversion, which simplifies and improves the efficiency of the circuit configuration of the air conditioning system 1.

[0052] As shown in Figure 4, the inverter control board 78 and the motor control board 20 are connected to the power line 55. In other words, the power line 55 functions as a so-called bus.

[0053] The inverter control board 78 is driven by DC power supplied from the converter unit 72b and functions as a control unit that controls each part of the power control device 33. The inverter control board 78 is communicated to the outdoor controller 39 via a communication line 40. The inverter control board 78 controls each part of the power control device 33 based on signals from the communication line 40.

[0054] The inverter control board 78 includes a processor 78a and a memory 78b. The processor 78a is a processor such as a CPU or MPU. The processor 78a controls the operation of each part of the power control device 33 by reading and executing control programs stored in the memory 78b. The processor 78a performs the first operation and the second operation by reading and executing the control program stored in memory 78b.

[0055] The first operation is to control each part of the power control device 33 so that the voltage value measured by the voltage sensor 86 matches the target voltage value, and the current value measured by the current sensor 84 matches the target current value. The first operation will be further explained with reference to Figure 6.

[0056] The second operation is to control the voltage value Vout of the output power output from the power control device 33 when switching from normal operation mode to independent operation mode in the event of a power outage. The second operation will be further explained with reference to Figures 7 and 8.

[0057] Memory 78b is a storage unit that stores various data such as control programs. Memory 78b stores control programs and data to be processed by processor 78a. Memory 78b has a non-volatile storage area. Alternatively, memory 78b may also have a volatile storage area and constitute the work area of ​​processor 78a.

[0058] A current sensor 84 is provided on the power line 71. The current sensor 84 is a sensor that detects the current value in the power line 71. In the power line 71, the current sensor 84 is installed between the electrolytic capacitor 80 and the DC reactor 82. This allows the current sensor 84 to detect the current value in the DC reactor 82 while suppressing the influence of noise from the electrolytic capacitor 80. The current sensor 84 is connected to the inverter control board 78 via a signal line 81. The inverter control board 78 can acquire the current value detected by the current sensor 84 via the signal line 81.

[0059] A voltage sensor 86 is provided on the power line 55 via a pair of signal lines 83. The voltage sensor 86 is a sensor that detects the voltage value in the power line 55. The voltage sensor 86 has identical detection circuits provided on each of the pair of signal lines 83. The voltage sensor 86 is connected to the inverter control board 78 via a pair of signal lines 83. The inverter control board 78 can acquire the voltage value detected by the voltage sensor 86 via the signal lines 83.

[0060] As described above, the voltage sensor 86 is equipped with identical detection circuits on each of the pair of signal lines 83. Therefore, the inverter control board 78 acquires each of the voltage values ​​detected by the two detection circuits. The inverter control board 78 compares these two voltage values. As a result, if the two voltage values ​​differ by more than a predetermined value, the inverter control board 78 can detect that a malfunction has occurred in the voltage sensor 86.

[0061] [2. First Action] The first operation of the air conditioning system 1, configured as described above, will be explained below. First, let's explain the normal operation mode, which is the basic operation of the air conditioning system 1. The normal operating mode is the operating mode of the air conditioning system 1 when power is supplied from the commercial power supply 36. As shown in Figure 1, in this mode, the power changeover panel 50 switches the power changeover switch 52 and the power changeover switch 352 to the first terminal 52a and the first terminal 352a sides, respectively, according to the control of the outdoor controller 39 provided by the outdoor unit 2A.

[0062] As a result, the power supplied from the commercial power supply 36 is supplied to each part of the outdoor units 2A to 2D via the upstream power supply line 51a, the power changeover switch 52, the power line 34a, and the power branch line 34a1. Furthermore, the power supplied from the commercial power supply 36 is supplied to the indoor units 13a to 13d, the lighting device 38, and the outlet 60 via the power changeover switch 352 and the downstream power supply line 51b.

[0063] In the outdoor unit 2A during normal operation mode, the three-phase full-wave rectifier diode 70 converts the AC voltage of the AC power sent from the generator 11 into a DC voltage. The converter unit 72b supplies the power converted by the three-phase full-wave rectifier diode 70 to the motor unit of the outdoor unit 2 as DC power maintained at a predetermined DC voltage. In contrast, during normal operation, the inverter unit 72a does not function. In other words, during normal operation, the inverter unit 72a does not output AC power.

[0064] Figure 5 is a schematic diagram showing the power grid of an air conditioning system during a power outage. Next, we will explain the standalone operation mode of the air conditioning system 1 during power outages, etc. In this mode, the outdoor unit 2A, which is the master unit, operates as the control unit. As shown in Figure 5, if the power supply from the commercial power source 36 is interrupted due to a power outage or the like, the outdoor units 2A to 2D, indoor units 13a to 13d, and lighting equipment 38 will stop because they will no longer receive power.

[0065] In this power outage state, if the user manually operates the self-contained operation switch 56 on the outdoor unit 2A to "on," as shown in Figure 2, DC power from the battery 49 is supplied to the outdoor unit control board 39c of the outdoor controller 39 at the moment the self-contained operation switch 56 is turned on. Then, according to the control of the outdoor controller 39, the DC power from the battery 49 is converted to DC200V by a DC / DC converter (not shown) and supplied as the power supply for the outdoor controller 39.

[0066] Next, the outdoor controller 39 of outdoor unit 2A starts switching from normal operation mode to independent operation mode. In this case, the outdoor controller 39 uses the power from the battery 49 to drive the starter motor and start the gas engine 10. Once the gas engine 10 starts, power generation by the generator 11 begins. In this embodiment, in order to prioritize power generation and start air conditioning operation after the generators 11 of all outdoor units 2A to 2D have started, the outdoor controller 39 postpones starting the compressor 12 even after the gas engine 10 has started. Therefore, in the air conditioning system 1, it is not necessary to operate the compressor 12 when it is desired to supply power only to the lighting device 38 and the outlet 60, and power can be supplied efficiently.

[0067] Next, the outdoor controller 39 of the outdoor unit 2A determines whether or not power for independent operation has been output from its own generator 11. Specifically, since the power output from the generator 11 is input to the power control device 33, the outdoor controller 39 makes this determination based on whether or not power has been input to this power control device 33.

[0068] When power for independent operation is output from the generator 11, the outdoor controller 39 outputs power for independent operation to the power switch panel 50 via the power control device 33. As a result, as shown in Figure 5, the power change switch 52 and the power change switch 352 of the power switch panel 50 switch to the second terminal 52b and the second terminal 352b, respectively, which are terminals for independent operation. Then, the outdoor units 2A to 2D, including the power control device 33, are disconnected from the commercial power supply 36, and the outdoor units 2A to 2D are connected to the indoor units 13a to 13d, the lighting device 38, and the outlet 60. As a result, an independent system, i.e., a self-sustaining system, is formed in the air conditioning system 1, disconnected from the commercial grid, and independent operation begins.

[0069] In the outdoor unit 2A, when the gas engine 10 starts up and the generator 11 begins generating electricity, the three-phase full-wave rectifier diode 70 converts the AC voltage of the AC power sent from the generator 11 into a DC voltage. The converter unit 72b supplies the power converted by the three-phase full-wave rectifier diode 70 as DC power maintained at a predetermined DC voltage to the motor unit of the outdoor unit 2A.

[0070] In contrast, the inverter unit 72a outputs AC power, maintaining the power converted by the three-phase full-wave rectifier diode 70 at a predetermined AC voltage. As shown in Figure 5, this AC power is supplied as generated power to outdoor units 2B through 2D via power line 34b (for standalone operation), power change switch 52, power line 34a, and power branch line 34a1 in sequence.

[0071] Next, the outdoor controller 39 of outdoor unit 2A uses the power generated by outdoor unit 2A to drive the starter motors of the gas engines 10 of outdoor units 2B to 2D, thereby starting the gas engines 10. Once the gas engines 10 start, power generation by the generators 11 of outdoor units 2B to 2D begins. The outdoor controller 39 of outdoor unit 2A determines whether or not power for independent operation has been output from the generator 11 of outdoor units 2B to 2D. Since the power output from the generator 11 is input to the power control device 33, the outdoor controller 39 makes the determination based on whether or not power has been input to the power control device 33.

[0072] When power is output from generator 11, the outdoor controller 39 of outdoor unit 2A adjusts the power output from each of the power control devices 33 of outdoor units 2B to 2D to superimpose it on the power output from outdoor unit 2A. Specifically, in outdoor unit 2A, the power control device 33 operates to maintain the voltage of the generated power output at a predetermined value. In outdoor units 2B to 2D, each of the power control devices 33 operates to maintain the current of the generated power output at a predetermined value, according to the voltage value of the generated power output from outdoor unit 2A. As a result, the power generated from outdoor unit 2A (master unit) and outdoor units 2B to 2D (slave units) is supplied to the downstream side with the wavelength, phase, etc. matched. As shown in Figure 5, in outdoor units 2B to 2D, the generated power is supplied to the power branch line 34a1 via the power supply line 34b1.

[0073] Furthermore, as shown in Figure 5, a transformer 57 is placed between the power supply line 34b1 and the power distribution line 34a1. In other words, as described with reference to Figure 3 for power distribution line 34b, the output power of the voltage value Vout generated by each generator 11 of outdoor units 2B to 2D and sent out from the filter board 74 is supplied to the power distribution line 34a1 via the transformer 57. The transformer 57 adjusts the load voltage value Vd, which is the voltage value of the load voltage output to the indoor units 13a to 13d, the lighting device 38, and the outlet 60. In other words, the transformer 57 adjusts the voltage value Vout of the output power sent from each of the filter boards 74 of the outdoor units 2B to 2D to the load voltage value Vd. The voltage value Vout is, for example, 200V, and the load voltage value Vd is 200V or 100V. Indoor units 13a to 13d, lighting device 38, and outlet 60 correspond to an example of a "load".

[0074] To operate any of the indoor units 13a to 13d, the remote control 5 is operated. This drives the compressor 12 of the corresponding outdoor unit 2A to 2D, causing the refrigerant to circulate within the refrigerant circuit and enabling air conditioning operation.

[0075] As described above, during independent operation, the upstream power supply line 51a is disconnected from outdoor units 2A to 2D by the power transfer panel 50, and power from the generator 11 is not supplied to the commercial power supply 36 upstream of the power transfer panel 50. Therefore, the air conditioning system 1 can prevent reverse power flow to the commercial power supply 36 side during independent operation with a simple structure, and it is possible to operate the desired indoor units 13a to 13d, lighting device 38, and outlet 60. Therefore, in the air conditioning system 1, even when power is supplied by a generator 11 with limited power generation capacity, it is possible to operate the desired equipment in the event of a power outage. Furthermore, in the air conditioning system 1, even in the event of a power outage or other disruptive situation, it is possible to quickly operate equipment that has been pre-selected and placed on the independent grid, without having to select the equipment to be operated on the spot.

[0076] Furthermore, during independent operation, a portion of the power that flows from the generator 11 to the downstream power supply line 51b returns to the outdoor unit 2A through the power line 41, and power is supplied to the battery 49 of the main unit, the outdoor unit 2A, via the power line 47b, etc. In other words, the battery 49 of the outdoor unit 2A is charged even during independent operation.

[0077] Next, the first operation of the power control device 33 will be described. Figure 6 is a flowchart showing the first operation of the power control device 33. In the power control device 33, the inverter control board 78 calculates a target voltage value (step SA1). In this embodiment, the target voltage value is preset to, for example, 200V, which is about the same as the AC voltage supplied from the commercial power supply 36. Next, the inverter control board 78 acquires the measured voltage value from the voltage sensor 86 (step SA2).

[0078] The inverter control board 78 compares the target voltage value with the measured voltage value and performs feedback control (step SA3). Next, the inverter control board 78 sets the result of the feedback control in step SA3 to the target current value (step SA4).

[0079] Next, the inverter control board 78 acquires the measured current value of the current sensor 112 (step SA5). The inverter control board 78 compares the target current value set in step SA4 with the measured current value obtained in step SA5 and performs feedback control (step SA6). Next, the inverter control board 78 performs so-called PWM (Pulse Width Modulation) control by outputting the result of the feedback control in step SA6 to the IPM board (step SA7).

[0080] As described in steps SA5 and SA6, in the power control device 33, the inverter control board 78 senses a current value that responds faster than the voltage value at which a first-order lag occurs, and controls that current value. Therefore, the power control device 33 can detect the power flowing through the power line 73 with higher accuracy, and based on this detection, it can achieve higher controllability and drive the IPM board 72. The IPM board 72 can realize an inverter section 72a that supplies AC power and a converter section 72b that supplies DC power. Furthermore, the IPM board 72 can switch the start and stop of the operation of the inverter section 72a and the converter section 72b according to the operating status of the outdoor units 2A to 2D.

[0081] In addition, the power control device 33 can stably supply power to other power loads, such as electric vehicles, even when other power loads are connected to the power line 55 which functions as a bus line, such as a power supply line that can supply power to other power loads.

[0082] [3. Second Action] Next, with reference to Figure 7, the second operation of the power control device 33 will be described. When a power outage occurs and the user manually switches the independent operation switch 56 on the outdoor unit 2A to "on," the outdoor controller 39 switches the power switch 52 from normal operation mode to independent operation mode. The inverter control board 78 of the power control device 33 controls the inverter section 72a so that the voltage value Vout of the AC power output from the power control device 33 becomes a first voltage value V1 that is less than or equal to the threshold voltage value VT1 when switching from normal operation mode to independent operation mode. Note that the voltage value Vout is the effective voltage value (RMS: Root-Mean-Square). The threshold voltage value VT1 is, for example, 30V. Furthermore, the power control device 33 supplies AC power with a first voltage value V1 to the power load, including indoor units 13a to 13d, lighting device 38, and outlet 60, via the transformer 57 by turning on a relay (not shown in the figure).

[0083] Furthermore, the inverter control board 78 controls the inverter unit 72a so that the voltage value Vout of the AC power output from the power control device 33 becomes a predetermined voltage value VA after a predetermined time PD has elapsed from the time T1 when switching from normal operation mode to independent operation mode. The predetermined voltage value VA is the load voltage value Vd, which is set according to the load, and is, for example, 200V. The predetermined time PD is, for example, 17 seconds.

[0084] For example, the inverter control board 78 controls the inverter section 72a so that the voltage value Vout increases in a ramp-like manner so that the voltage value Vout becomes a predetermined voltage value VA after a predetermined time PD has elapsed from the time T1 when switching from normal operation mode to independent operation mode. Furthermore, the inverter control board 78 determines a threshold voltage value VT1 and a predetermined time PD based on a predetermined voltage value VA and the power consumed by the load. For example, the higher the predetermined voltage value VA, the higher the threshold voltage value VT1 and the longer the predetermined time PD. Also, the lower the power consumed by the load, the higher the threshold voltage value VT1 and the shorter the predetermined time PD.

[0085] Figure 7 is a graph showing an example of the voltage value Vout of the AC power output from the power control device 33. The horizontal axis of the graph represents time T, and the vertical axis represents the voltage value Vout of the AC power output from the power control device 33. The inverter control board 78 controls the voltage value Vout of the AC power output from the power control device 33 by controlling the inverter unit 72a when switching from normal operation mode to independent operation mode in the event of a power outage.

[0086] Time point T1 is when the system switches from normal operation mode to independent operation mode in the event of a power outage. Specifically, time point T1 is the point at which the system begins supplying the generated power to the load, as shown below. That is, the user manually operates the independent operation switch 56 on the outdoor unit 2A to "on," the starter motor is driven by the power of the battery 49, the gas engine 10 is started, power generation by the generator 11 begins, and the system begins supplying the generated power to the load. The inverter control board 78 controls the inverter section 72a so that the voltage value Vout becomes "0" V up to time T1. At time T1, the inverter control board 78 controls the inverter section 72a so that the voltage value Vout becomes a first voltage value V1 from "0" V. The first voltage value V1 is, for example, 30 V.

[0087] Between time point T1 and time point T2, the inverter control board 78 controls the inverter unit 72a so that the voltage value Vout increases by 10V every second. Then, from time point T2 onward, the inverter control board 78 controls the inverter unit 72a so that the voltage value Vout becomes a second voltage value V2. The second voltage value V2 is, for example, 200V.

[0088] Next, with reference to Figure 8, a second example of the operation of the power control device 33 will be described. Figure 8 is a flowchart showing a second example of the operation of the power control device 33. First, in step S101, the inverter control board 78 of the power control device 33 determines whether or not to switch from normal operation mode to independent operation mode when a power outage occurs. The inverter control board 78 determines, for example, that to switch from normal operation mode to independent operation mode if the independent operation changeover switch 56 provided on the outdoor unit 2A is operated to "on" by the user's manual operation. If the inverter control board 78 determines that it will not switch from normal operation mode to independent operation mode (step S101; NO), the process enters a standby state. If the inverter control board 78 determines that it will switch from normal operation mode to independent operation mode (step S101; YES), the process proceeds to step S103.

[0089] Then, in step S103, the inverter control board 78 instructs the outdoor controller 39 to switch the power change switch 52 to the independent operation mode. The outdoor controller 39 then switches the power change switch 52 from the normal operation mode to the independent operation mode. Next, in step S105, the inverter control board 78 sets the voltage value Vout of the AC power output from the power control device 33 to a first voltage value V1 that is less than or equal to the threshold voltage value VT1. The first voltage value V1 is, for example, 30V. That is, the inverter control board 78 controls the inverter unit 72a to generate AC power with the first voltage value V1. Next, in step S107, the inverter control board 78 turns on a relay (not shown) to supply AC power with a first voltage value V1 to the power load, including indoor units 13a to 13d, lighting device 38, and outlet 60, via the transformer 57. Next, in step S109, the inverter control board 78 controls the voltage value Vout of the AC power output from the power control device 33 to increase in a ramp-like manner. For example, as explained with reference to Figure 7, the inverter control board 78 controls the voltage value Vout to increase by 10V every second. Next, in step S111, the inverter control board 78 determines whether the voltage value Vout of the AC power output from the power control device 33 has reached the second voltage value V2. If the inverter control board 78 determines that the voltage value Vout has not reached the second voltage value V2 (step S111; NO), the process returns to step S109. If the inverter control board 78 determines that the voltage value Vout has reached the second voltage value V2 (step S111; YES), the process proceeds to step S113. The second voltage value V2 is, for example, 200V. Then, in step S113, the inverter control board 78 controls the voltage value Vout to be maintained at the second voltage value V2. After that, the process ends.

[0090] Next, with reference to Figure 9, another example of the second operation of the power control device 33 will be described. Figure 9 is a flowchart showing another example of the second operation of the power control device 33. First, in step S201, the inverter control board 78 of the power control device 33 determines whether or not to switch from normal operation mode to independent operation mode when a power outage occurs. The inverter control board 78 determines, for example, that to switch from normal operation mode to independent operation mode if the independent operation changeover switch 56 provided on the outdoor unit 2A is operated to "on" by the user's manual operation. If the inverter control board 78 determines that it will not switch from normal operation mode to independent operation mode (step S201; NO), the process enters a standby state. If the inverter control board 78 determines that it will switch from normal operation mode to independent operation mode (step S201; YES), the process proceeds to step S203.

[0091] Then, in step S203, the inverter control board 78 instructs the outdoor controller 39 to switch the power change switch 52 to the independent operation mode. The outdoor controller 39 then switches the power change switch 52 from the normal operation mode to the independent operation mode. Next, in step S205, the inverter control board 78 turns on a relay (not shown) to make the AC power output from the inverter unit 72a available for supply to the power load, including the indoor units 13a to 13d, the lighting device 38, and the outlet 60, via the transformer 57. Next, in step S207, the inverter control board 78 sets the voltage value Vout of the AC power output from the power control device 33 to a first voltage value V1 that is less than or equal to the threshold voltage value VT1. The first voltage value V1 is, for example, 30V. That is, the inverter control board 78 controls the inverter unit 72a to generate AC power of the first voltage value V1 and supplies it to the transformer 57. Next, in step S209, the inverter control board 78 controls the voltage value Vout of the AC power output from the power control device 33 to increase in a ramp-like manner. For example, as explained with reference to Figure 7, the inverter control board 78 controls the voltage value Vout to increase by 10V every second. Next, in step S211, the inverter control board 78 determines whether the voltage value Vout of the AC power output from the power control device 33 has reached the second voltage value V2. If the inverter control board 78 determines that the voltage value Vout has not reached the second voltage value V2 (step S211; NO), the process returns to step S209. If the inverter control board 78 determines that the voltage value Vout has reached the second voltage value V2 (step S211; YES), the process proceeds to step S213. The second voltage value V2 is, for example, 200V. Then, in step S213, the inverter control board 78 controls the voltage value Vout to be maintained at the second voltage value V2. After that, the process ends.

[0092] [4. Effects, etc.] As described above, in this embodiment, the outdoor unit 2 of an air conditioner comprises a compressor 12, a gas engine 10 that drives the compressor 12, a generator 11 driven by the gas engine 10, and a power control device 33 having an inverter unit 72a that controls the output power from the generator 11. The output power is supplied to the load via a transformer that adjusts the load voltage, which is the voltage output to the load. The power control device 33 controls the voltage value Vout of the output power to be less than or equal to a threshold voltage value VT1 by controlling the inverter unit 72a when switching from the commercial power supply 36 to the output power. The power control device 33 controls the voltage value Vout of the output power by controlling the inverter unit 72a so that the voltage value Vout of the output power becomes a predetermined voltage value VA set according to the load after a predetermined time PD has elapsed from the time T1 when switching from the commercial power supply 36 to the output power. As a result, when switching from commercial power supply 36 to output power from generator 11, the voltage value Vout of the output power from generator 11 is controlled to be below the threshold voltage value VT1. By setting the threshold voltage value VT1 to an appropriate value, the inrush current flowing into transformer 57 can be suppressed. Furthermore, by controlling the inverter section 72a, the voltage value Vout is controlled to be below the threshold voltage value VT1, thus enabling control of the voltage value Vout to be below the threshold voltage value VT1 with a simple configuration. Furthermore, in order to control the voltage value Vout of the output power so that after a predetermined time PD has elapsed from time T1, the voltage value Vout becomes a predetermined voltage value VA set according to the load, damage to the transformer 57 can be suppressed by appropriately setting the predetermined time PD.

[0093] Furthermore, in the outdoor unit 2 of the air conditioner, the power control device 33 controls the inverter unit 72a to increase the voltage value Vout of the output power in a ramp-like manner from the time T1 when the power changeover switches 52 and 352 are switched from commercial power supply 36 to the output power until a predetermined time PD has elapsed. This controls the voltage value Vout of the output power to increase in a ramp-like manner from time T1 until after a predetermined time PD has elapsed, thereby suppressing damage to the transformer 57 during the period from time T1 until after the predetermined time PD has elapsed.

[0094] Furthermore, in the outdoor unit 2 of the air conditioning system, the power control device 33 determines a threshold voltage value VT1 and a predetermined time PD based on a predetermined voltage value VA and the power consumed by the load. The power control device 33 determines a threshold voltage value VT1 and a predetermined time PD based on a predetermined voltage value VA and the power consumed by the load, and can therefore determine the threshold voltage value VT1 and the predetermined time PD to appropriate values.

[0095] (Other embodiments) As described above, embodiments have been explained as examples of the technology disclosed in this application. However, the technology in this disclosure is not limited to these embodiments and can be applied to embodiments that have been modified, replaced, added, or omitted. Furthermore, it is possible to create new embodiments by combining the components described in the above embodiments. Therefore, other embodiments are illustrated below.

[0096] The embodiments described above illustrate one aspect of the present invention and can be arbitrarily modified and applied without departing from the spirit of the invention.

[0097] In the embodiment described above, the air conditioning system 1 is said to be equipped with multiple outdoor units 2A to 2D, but it is not limited to this and may be equipped with only outdoor unit 2A.

[0098] In the embodiment described above, the outdoor units 2B to 2D, the power branch line 34a1, and the commercial power line may be connected via a switch such as a power changeover switch 52. This switch may be provided in the power changeover panel 50.

[0099] In the embodiment described above, the inverter control board 78 controls the inverter section 72a so that the voltage value Vout increases linearly, but is not limited to this. The inverter control board 78 may control the inverter section 72a so that the voltage value Vout increases in a ramp-like manner. For example, the inverter control board 78 may control the inverter so that the voltage increase per unit time of the voltage value Vout increases as the voltage value Vout increases.

[0100] In the embodiment described above, the power control device 33 determines a threshold voltage value VT1 and a predetermined time PD based on a predetermined voltage value VA and the power consumed by the load, but is not limited to this. The power control device 33 only needs to determine at least one of the threshold voltage value VT1 and the predetermined time PD based on a predetermined voltage value VA and the power consumed by the load.

[0101] Since the embodiments described above are for illustrative purposes of the technology described herein, various modifications, substitutions, additions, omissions, etc., can be made within the claims or their equivalents.

[0102] (Note) (Technology 1) An outdoor unit of an air conditioning system comprising a compressor, a gas engine that drives the compressor, a generator driven by the gas engine, and a power control device that has an inverter and controls the output power from the generator, wherein the output power is supplied to the load via a transformer that adjusts the load voltage, which is the voltage output to the load, and the power control device controls the voltage value of the output power to be less than or equal to a threshold voltage value by controlling the inverter when switching from commercial power to the output power, and the power control device controls the voltage value of the output power by controlling the inverter so that the voltage value of the output power becomes a predetermined voltage value set according to the load after a predetermined time has elapsed from the time of switching from commercial power to the output power. This configuration allows for the suppression of inrush current flowing into the transformer by controlling the voltage value of the output power to be below a threshold voltage value when the changeover switch is switched from the commercial power supply to the output power. Furthermore, by controlling the inverter, the voltage value of the output power can be controlled to be below a threshold voltage value with a simple configuration. Furthermore, damage to the transformer can be suppressed by appropriately setting a predetermined time to control the voltage value of the output power so that, after a predetermined time has elapsed from the time of switching from the commercial power supply to the output power, the output voltage becomes a predetermined voltage value set according to the load.

[0103] (Technology 2) The outdoor unit of an air conditioner according to Technology 1, wherein the power control device controls the inverter to increase the voltage value of the output power in a ramp-like manner from the time the changeover switch is switched from the commercial power supply to the output power until after a predetermined time has elapsed. This configuration allows for the control of the voltage value of the output power to increase in a ramp-like manner from the time of switching from the commercial power supply to the output power until after the predetermined time has elapsed, thereby suppressing damage to the transformer.

[0104] (Technical 3) The outdoor unit of an air conditioning system according to Technical 1 or Technical 2, wherein the power control device determines at least one of the threshold voltage value and the predetermined time based on the predetermined voltage value and the power consumed by the load. This configuration allows at least one of the threshold voltage value and the predetermined time to be determined to an appropriate value. [Industrial applicability]

[0105] This disclosure is applicable to the outdoor unit of an air conditioning system that uses a gas engine as the drive source for the compressor. [Explanation of Symbols]

[0106] 1. Air conditioning system 1A~1D Air Conditioning System 2 Outdoor unit 2A~2D outdoor unit 10 Gas engines 11 Generators 12 Compressor 13a~13d Indoor unit (part of the load) 20 Electric Unit Control Board 26a Fan motor 27a Pump motor 33 Power control device 36 Commercial power supply 38 Lighting equipment (part of the load) 39c Outdoor unit control board 49 batteries 50 Power Switching Panel (Switching Panel) 52,352 Power selector switch (selector switch) 60 outlets (part of the load) 72 IPM board 72a Inverter section (inverter) 72b Converter Section 74 Filter substrate 78 Inverter control board PD predetermined time Vout voltage value V1 First voltage value V2 Second voltage value

Claims

1. An outdoor unit of an air conditioning system comprising a compressor, a gas engine that drives the compressor, a generator driven by the gas engine, and a power control device that has an inverter and controls the output power from the generator, The output power is supplied to the load via a transformer that adjusts the load voltage, which is the voltage output to the load. The power control device controls the inverter when switching from commercial power to the output power, thereby controlling the voltage value of the output power to be below a threshold voltage value. The power control device controls the voltage value of the output power by controlling the inverter so that the voltage value of the output power becomes a predetermined voltage value set according to the load, after a predetermined time has elapsed from the time of switching from the commercial power supply to the output power. Outdoor unit of an air conditioning system.

2. The power control device controls the inverter to increase the voltage value of the output power in a ramp-like manner from the time of switching from the commercial power supply to the output power until after the predetermined time has elapsed. The outdoor unit of the air conditioning system according to claim 1.

3. The power control device determines at least one of the threshold voltage value and the predetermined time based on the predetermined voltage value and the power consumed by the load. An outdoor unit for an air conditioning system according to claim 1 or claim 2.

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