Air blower

Abstract

To automatize setting of an external static pressure.SOLUTION: A control device 6 selects a control mode used for control of an electric motor 9B by comparing a present fan characteristic and an assumed fan characteristic. Thereby, in a blower device, a control mode corresponding to an automatic and proper external static pressure can be selected. Also, in the blower device, the external static pressure is set without depending on the experience and gut reaction of an operator. Note that the present fan characteristic means a relation between the present fan drive frequency and the present air blowing amount detected by an air amount detection part 10B. The assumed fan characteristic is information which shows the relation between fan drive frequency stored in a storage part 10A beforehand, and the air amount.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a blower device that blows air through a duct connected to the interior.

Background Art

[0002] In order to blow air through a duct, the static pressure generated by the blower device at the air outlet of the blower device, that is, the inlet of the duct (hereinafter referred to as the external static pressure), needs to be a pressure greater than the pressure loss generated in the duct.

[0003] For this reason, for example, the blower device described in Patent Document 1 has a function of "comparing the supply air static pressure with the maximum static pressure stored in advance and issuing an alarm to the user when the supply air static pressure is greater than the maximum supply air static pressure".

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The external static pressure varies for each site where the blower device is installed. In other words, even for blower devices of the same specification, if the installation site is different, the actual fan characteristics will also be different. That is, even if the fan speed is the same in blower devices of the same specification, the actual air volume will be different for each installation site.

[0006] For this reason, conventionally, for each installation site, the installer manually selects a control mode suitable for that installation site so that the fan characteristics assumed by the designer at the time of design can be obtained.

[0007] Note that "selecting a control mode" is also referred to as "setting the static pressure outside the unit". Therefore, in building air conditioners and the like, a setting unit for setting the static pressure outside the unit is usually provided. Then, during installation work or the like, the operator selects and sets an appropriate static pressure outside the unit by himself / herself.

[0008] However, it is difficult for the operator to select an appropriate static pressure outside the unit, that is, the magnitude of the pressure loss generated in the duct. Therefore, at present, the selection of the static pressure outside the unit has to rely on the experience and intuition of the operator. The present disclosure discloses an example of a blower device in view of this point.

Means for Solving the Problem

[0009] The blower device connected to the duct leading to the room and blowing air through the duct preferably includes at least one of the following constituent elements.

[0010] That is, the constituent elements are a blower fan (9A), an electric motor (9B) for rotating the fan (9A), a drive unit (9C) for driving the electric motor (9B), and a control unit (6) for controlling the electric motor (9B) using any one of a plurality of predetermined control modes, wherein the control unit (6) transmits a command signal for controlling the electric motor (9B) to the drive unit (9C), a control mode determination unit (6) for selecting a control mode to be used for controlling the electric motor (9B) from among the plurality of control modes, a storage unit (10A) in which information indicating the relationship between the command signal and the air volume is stored in advance, and an air volume detection unit (10B) for detecting the air volume. The control mode determination unit (6) selects a control mode to be used for controlling the electric motor (9B) by comparing the current fan characteristics and the assumed fan characteristics.

[0011] Note that the current fan characteristics refer to the relationship between the current command signal and the current air volume detected by the air volume detection unit (10B). The assumed fan characteristics refer to the information stored in the storage unit (10A).

[0012] As a result, in the blower device, a control mode corresponding to an appropriate automatic external static pressure can be selected. Consequently, in the blower device, the external static pressure is set without relying on the experience and intuition of the operator.

[0013] Incidentally, the reference signs in each of the above parentheses are an example showing the correspondence with the specific configuration and the like described in the embodiments described later, and the present disclosure is not limited to the specific configuration and the like indicated by the reference signs in the above parentheses.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0015] The following "Embodiments of the Invention" show an example of embodiments belonging to the technical scope of the present disclosure. That is, the invention-specific matters described in the claims are not limited to the specific configurations, structures, and the like shown in the following embodiments.

[0016] At least the members or parts described with reference signs are provided with at least one, unless otherwise stated such as "one". That is, when there is no statement such as "one", two or more of the members may be provided. The air conditioner shown in the present disclosure includes at least the components described with reference signs and the structural elements shown in the drawings.

[0017] (First Embodiment) <1. Outline of the Air Conditioner> This embodiment applies an example of the air-conditioning device and the blower device according to the present disclosure to an air-conditioning device that air-conditions a server room such as a data center or a communication machine room. The air-conditioning device is a so-called "package air conditioner" composed of a vapor compression refrigerator.

[0018] The air-conditioning device 1 shown in FIG. 1 generates cooling or heating (cooling in this embodiment) for air-conditioning the server room. The air-conditioning device 1 includes a compressor 2, a condenser 3, an expansion valve 4, an evaporator 5, a control device 6, first temperature sensors 7A to 7D, a first pressure sensor 7E, a second pressure sensor 7F, a first blower 8, a second blower 9, and the like.

[0019] The compressor 2 compresses the low-pressure vapor refrigerant and supplies it to the condenser 3. The compressor 2 is driven by an electric motor (not shown). The electric motor is driven by an inverter-type drive circuit (not shown). The operation of the drive circuit is controlled by the control device 6.

[0020] The drive circuit supplies a drive current to the electric motor and can change the frequency of the drive current (hereinafter referred to as the compressor drive frequency). The drive circuit supplies a drive current with a compressor drive frequency corresponding to the command frequency from the control device 6 to the electric motor. That is, the operation of the compressor 2 is controlled by the control device 6 via the drive circuit.

[0021] The condenser 3 is a high-pressure side heat exchanger that cools the high-pressure refrigerant compressed by the compressor 2. In the condenser 3, the vapor refrigerant is cooled and liquefied (condensed). The expansion valve 4 decompresses and expands the high-pressure refrigerant flowing out of the condenser 3 and supplies it to the evaporator 5.

[0022] The evaporator 5 evaporates the liquid-phase low-pressure refrigerant to generate cooling. The first blower 8 blows cooling air to the condenser 3. The second blower 9 generates an air flow that passes through the evaporator 5 and is supplied into the server room.

[0023] That is, the second blower 9 sucks in the air in the server room and supplies it to the evaporator 5, and supplies the air cooled by the evaporator 5 to the server room through a duct (not shown). The duct is a member that constitutes an air passage connecting from the evaporator 5 to the server room.

[0024] The duct includes not only a duct made of a so-called metal plate, but also an air passage formed under the floor or on the ceiling of the server room. That is, the duct constitutes an air passage for introducing the air flow induced by the second blower 9 into the server room.

[0025] Detection signals of the first temperature sensor 7A to the fourth temperature sensor 7D, the first pressure sensor 7E, and the second pressure sensor 7F are input to the control device 6. The first temperature sensor 7A detects the temperature of the air before being cooled by the evaporator 5. The second temperature sensor 7B detects the temperature of the air after being cooled by the evaporator 5.

[0026] The third temperature sensor 7C detects the refrigerant temperature at the refrigerant outlet of the evaporator 5. The fourth temperature sensor 7D detects the refrigerant temperature at the refrigerant inlet of the evaporator 5. The first pressure sensor 7E detects the refrigerant pressure in the evaporator 5. The second pressure sensor 7F detects the discharge pressure of the compressor 2, that is, the pressure of the high-pressure refrigerant.

[0027] <Control device> The control device 6 controls at least the opening degrees of the compressor 2, the second blower 9, and the expansion valve 4. That is, the control device 6 has a compressor control unit, an expansion valve control unit, a fan control unit, etc. The control device 6 is composed of a microcomputer having a CPU, a ROM, a RAM, etc.

[0028] Then, when the software stored in the non-volatile storage unit such as the ROM is executed by the CPU, the above-mentioned respective control units are realized. The compressor control unit controls the operation of the compressor 2, that is, the compressor drive frequency. The expansion valve control unit controls the opening degree of the expansion valve 4. The fan control unit controls the operation of the second blower 9.

[0029] <Compressor Control> The compressor control unit, that is, the control device 6, controls the rotational speed of the compressor 2 so that the temperature detected by the second temperature sensor 7B (hereinafter referred to as the blowing temperature) becomes a preset temperature (hereinafter referred to as the blowing suction set temperature).

[0030] Specifically, when the blowing temperature is higher than the blowing set temperature, the control device 6 increases the rotational speed of the compressor 2, and when the blowing temperature is lower than the blowing set temperature, the control device 6 decreases the rotational speed of the compressor 2, and performs PID control on the compressor drive frequency.

[0031] <Expansion Valve Control> The expansion valve control unit, that is, the control device 6, controls the opening degree of the expansion valve 4 so that the superheat degree of the refrigerant at the refrigerant outlet of the evaporator 5 becomes a predetermined superheat degree. Note that the control device 6 grasps the temperature difference between the detected temperature of the third temperature sensor 7C and the evaporation temperature calculated from the detected pressure of the first pressure sensor 7E as the superheat degree.

[0032] <2. Control of the Second Blower> The second blower 9 includes a blower fan 9A and an electric motor 9B that rotates the fan 9A. In this embodiment, an example of the blower device according to the present disclosure is applied to the second blower 9.

[0033] The blower device includes the second blower 9, a drive circuit 9C, a fan control unit, and the like. The drive circuit 9C is a drive unit that drives the electric motor 9B. Note that the drive circuit 9C according to this embodiment is an inverter type drive circuit.

[0034] The fan control unit includes a motor control unit, a control mode determination unit, an air volume detection unit 10B, a storage unit 10A, and the like. Note that the motor control unit, the control mode determination unit, and the air volume detection unit 10B are realized by software stored in a non-volatile storage unit being executed by a CPU.

[0035] The memory unit 10A is a non-volatile memory unit that stores in advance information showing the relationship between the command signal and the air volume when the pressure loss generated in the duct is used as a parameter (see FIG. 3). Note that the command signal is a signal having a frequency that matches the fan drive frequency described later.

[0036] The air volume detection unit 10B detects the air volume. The air volume detection unit 10B calculates the air volume by the following method. That is, first, the air volume detection unit 10B calculates the temperature difference between the detected temperature of the third temperature sensor 7C and the detected temperature of the fourth temperature sensor 7D, and of uses the temperature difference and the detected pressure of the first pressure sensor 7E to calculate the specific enthalpy difference between the refrigerant inlet and the refrigerant outlet of the evaporator 5.

[0037] Next, the air volume detection unit 10B calculates the mass flow rate using the drive frequency of the compressor 2, the detected pressure of the first pressure sensor 7E, the detected pressure of the second pressure sensor 7F, and the characteristics of the compressor 2. Then, the air volume calculation unit calculates the refrigerating capacity generated in the evaporator 5 by multiplying the specific enthalpy difference and the mass flow rate.

[0038] And the air volume detection unit 10B calculates the air volume by dividing the above refrigerating capacity by the specific heat of air, the density, and the temperature change ΔT of the air passing through the evaporator 5, that is, the temperature difference between the detected temperature of the first temperature sensor 7A and the detected temperature of the second temperature sensor 7B.

[0039] Note that since the temperature and relative humidity of the air in the server room are usually maintained within a predetermined range, fixed values are used as the specific heat and density of air in the present embodiment.

[0040] <2.1 Motor control unit> The motor control unit, that is, the control device 6, controls the operation of the electric motor 9B via the drive circuit 9C. That is, the drive circuit 9C supplies a drive current having a drive frequency corresponding to the command signal from the control device 6 to the electric motor 9B.

[0041] That is, the command signal is a signal having a frequency that matches the driving frequency when driving the electric motor 9B. Then, the control device 6 transmits the command signal toward the drive circuit 9C in accordance with the content of the control mode selected by the control mode determination unit.

[0042] Note that since the command signal is a signal having a frequency that matches the driving frequency of the electric motor 9B (hereinafter referred to as the fan driving frequency), the information stored in the storage unit 10A is information indicating the relationship between the fan driving frequency and the air volume.

[0043] <2.2 Control Mode Determination Unit> <Outline of Control Mode Determination Unit> The control mode determination unit, that is, the control device 6, selects a control mode to be used for controlling the electric motor 9B from among a plurality of predetermined control modes. Specifically, the control device 6 compares the current fan characteristics and the assumed fan characteristics and selects a control mode to be used for controlling the electric motor 9B.

[0044] The current fan characteristics refer to the relationship between the current command signal, that is, the current fan driving frequency, and the current air volume detected by the air volume detection unit 10B. The assumed fan characteristics refer to the information stored in the storage unit 10A. Hereinafter, the air volume stored in the storage unit 10A is referred to as the assumed air volume. The fan driving frequency corresponding to the assumed air volume is referred to as the assumed frequency.

[0045] <Control Mode> In each of the plurality of control modes according to the present embodiment, the fan driving frequency f1 is determined as a function value of the compressor driving frequency f2, and the minimum value fmin and the maximum value fmax of the fan driving frequency are set.

[0046] That is, f1 = Fn(f2), and fmin ≤ f1 ≤ fmax. Here, Fn (n = 1, 2, 3,...) is a function for determining f1. And the function Fn is a function determined for each control mode.

[0047] Furthermore, the minimum value fmin and the maximum value fmax of the fan drive frequency are determined for each control mode, and these values are different for each control mode. That is, the plurality of functions Fn, the minimum value fmin, and the maximum value fmax respectively correspond to the static pressure outside the machine.

[0048] Note that the subscript n of the function Fn indicates the degree of the static pressure outside the machine. And the larger n is, the greater the static pressure outside the machine to be set means. For this reason, the larger n is, the larger values are selected for the minimum value fmin and the maximum value fmax.

[0049] Therefore, the number of control modes coincides with the number of functions Fn. For this reason, hereinafter, any one of the plurality of control modes is denoted as control mode n (n = 1, 2, 3 ···). Note that the subscript n corresponds to the subscript n of the function Fn (hereinafter referred to as table number n).

[0050] <Details of the control mode determination unit> The control mode determination unit can operate in parallel independently of the operation of the motor control unit. Specifically, the control mode determination unit operates at a predetermined timing (for example, at intervals of 2 to 3 hours) in a state where the motor control unit is operating.

[0051] And the control mode determination unit, that is, the control device 6, compares the assumed air volume when the current fan drive frequency is the assumed frequency with the current air volume. Specifically, the control device 6 determines whether the current air volume belongs to a predetermined range with respect to the assumed air volume.

[0052] That is, when the current air volume is smaller than the lower limit value of the above range, the control device 6 selects a control mode of a static pressure outside the machine larger than the actual set static pressure outside the machine, that is, a control mode with a table number n one larger than the current table number n.

[0053] On the one hand, when the current air volume is greater than the upper limit value of the above range, the control device 6 selects a control mode of the external static pressure smaller than the actual set external static pressure, that is, the control mode of the table number n one smaller than the current table number n.

[0054] And when the current air volume belongs to the above range, the current control mode is maintained. When the set external static pressure becomes the largest, that is, when the table number n reaches the maximum value, the control device 6 issues a warning.

[0055] Figure 2 is a control flow showing the outline of the operation of the control mode determination unit. As shown in Figure 2, when the control is activated, the control device 6 calculates the current air volume (S1), and then determines whether the current air volume is smaller than the lower limit value of the above range (S2).

[0056] When the current air volume is smaller than the lower limit value of the above range (S2: YES), the control device 6 selects a control mode of the external static pressure larger than the actual set external static pressure (S3). Next, the control device 6 determines whether the set external static pressure has become the largest (S4). When the set external static pressure has become the largest (S4: YES), the control device 6 issues a warning (S5).

[0057] On the other hand, when the current air volume is not smaller than the lower limit value of the above range (S2: NO), the control device 6 determines whether the current air volume is greater than the upper limit value of the above range (S6). When the current air volume is greater than the upper limit value of the above range (S6: YES), the control device 6 selects a control mode of the external static pressure smaller than the actual set external static pressure (S7).

[0058] <3. Features of the air conditioner according to the present embodiment (particularly, control of the second blower)> According to the air conditioner 1, the control device 6 compares the current fan characteristics with the assumed fan characteristics and selects a control mode to be used for controlling the electric motor 9B. As a result, in the blower device, a control mode corresponding to an appropriate automatic external static pressure can be selected. Subsequently, in the blower device, the external static pressure is set without relying on the experience and intuition of the operator.

[0059] (Second Embodiment) In the above-described embodiment, the assumed air volume when the current fan driving frequency is the assumed frequency is compared with the current air volume. In contrast, in the present embodiment, the control mode to be used for controlling the electric motor 9B is selected by comparing the assumed power consumption when the current fan driving frequency is the assumed frequency with the actual power consumption.

[0060] That is, when the electric motor 9B is driven at the same fan driving frequency, if the pressure loss generated in the duct is different, the rotational speed of the electric motor 9B, that is, the operating point of the second blower 9 changes. Therefore, if the pressure loss generated in the duct is different, the power consumption of the electric motor 9B changes.

[0061] Therefore, in the present embodiment, as shown in FIG. 4, a power consumption detection unit 10B is provided instead of the air volume detection unit 10B. The power consumption detection unit 10B detects the power consumption (in the present embodiment, the consumed current) of the electric motor 9B.

[0062] In the storage unit 10A, information indicating the relationship between the fan driving frequency and the power consumption (in the present embodiment, the consumed current) of the electric motor 9B when the pressure loss generated in the duct is used as a parameter is stored in advance. Hereinafter, the consumed current stored in the storage unit 10A is referred to as the assumed consumed current.

[0063] That is, the control device 6 according to the present embodiment selects a control mode to be used for controlling the electric motor 9B by comparing the assumed consumed current when the current fan driving frequency is the assumed frequency with the actual consumed current.

[0064] Note that the same constituent elements as those in the above-described embodiments are denoted by the same reference numerals as those in the above-described embodiments. Therefore, in this embodiment, redundant descriptions are omitted.

[0065] <Details of the control mode determination unit> Similar to the first embodiment, the control mode determination unit according to this embodiment can operate in parallel independently of the operation of the motor control unit. Specifically, the control mode determination unit operates at a predetermined timing (for example, at intervals of 2 to 3 hours) while the motor control unit is operating.

[0066] Then, the control mode determination unit, that is, the control device 6, compares the assumed current consumption when the current fan drive frequency is the assumed frequency with the current current consumption. Specifically, the control device 6 determines whether the current current consumption belongs to a predetermined range with respect to the assumed current consumption. Incidentally, the said range is the range which added the arbitrary threshold value which exceeds the error range of a detected electric current and the error range of the drive circuit 9C centering on the assumed current consumption.

[0067] That is, when the current current consumption is smaller than the lower limit value of the above range, the control device 6 selects a control mode of an external static pressure larger than the actual set external static pressure, that is, a control mode of a table number n one larger than the current table number n.

[0068] On the other hand, when the current current consumption is larger than the upper limit value of the above range, the control device 6 selects a control mode of an external static pressure smaller than the actual set external static pressure, that is, a control mode of a table number n one smaller than the current table number n.

[0069] When the current current consumption belongs to the above range, the current control mode is maintained. Note that when the set external static pressure becomes the largest, that is, when the table number n reaches the maximum value, the control device 6 issues a warning.

[0070] FIG. 5 is a control flow showing an outline of the operation of the control mode determination unit. As shown in FIG. 5, when the control is activated, the control device 6 calculates the current power consumption (S11), and then determines whether the current power consumption is less than the lower limit value of the above range (S12).

[0071] If the current power consumption is less than the lower limit value of the above range (S12: YES), the control device 6 selects a control mode with an external static pressure greater than the actual set external static pressure (S13). Next, the control device 6 determines whether the set external static pressure has become the largest (S14). If the set external static pressure has become the largest (S14: YES), the control device 6 issues a warning (S15).

[0072] On the other hand, if the current power consumption is not less than the lower limit value of the above range (S12: NO), the control device 6 determines whether the current power consumption is greater than the upper limit value of the above range (S16). If the current power consumption is greater than the upper limit value of the above range (S16: YES), the control device 6 selects a control mode with an external static pressure smaller than the actual set external static pressure (S17).

[0073] Note that depending on the type of the blower, the fan characteristics may be different from the above, and the magnitude relationship of the power consumption may be different from the above. However, since this embodiment compares the assumed power consumption when the current fan drive frequency is the assumed frequency with the actual power consumption, this embodiment is applicable even in such a case. (Other Embodiments) In the above embodiment, the rotation speed of the compressor 2 is controlled so that the blown-out temperature becomes the blown-in and sucked-in set temperature. However, the present disclosure is not limited to this. That is, the present disclosure is applicable to an air conditioner that controls the rotation speed of the compressor 2 so that the detected temperature of the first temperature sensor 7A (hereinafter referred to as the suction temperature) becomes a preset suction set temperature, for example.

[0074] That is, in this configuration, the control device 6 increases the rotational speed of the compressor 2 when the suction temperature is higher than the suction set temperature, and decreases the rotational speed of the compressor 2 when the suction temperature is lower than the suction set temperature.

[0075] Also, in this configuration, the control device 6 performs, for example, PID control on the fan drive frequency so that the blow-out temperature becomes a preset blow-out set temperature. Then, the control device 6 decreases the fan drive frequency when the blow-out temperature is higher than the blow-out set temperature, and increases the fan drive frequency when the blow-out temperature is lower than the blow-out set temperature. Note that the blow-out set temperature is a value obtained by subtracting a predetermined value from the suction temperature in the cooling operation.

[0076] In this configuration, since the fan drive frequency is controlled so that the blow-out temperature becomes the preset blow-out set temperature, the control of the fan drive frequency itself does not change even when the control mode is changed. However, when the control mode is changed, the minimum value fmin and the maximum value fmax of the fan drive frequency are changed.

[0077] In the above-described embodiment, the air volume detection unit 10B indirectly detects the air volume. However, the present disclosure is not limited to this. That is, the present disclosure may be, for example, an air volume detection unit 10B that directly measures the air volume.

[0078] In the above-described embodiment, a warning is issued when the table number n reaches the maximum value. However, the present disclosure is not limited to this. That is, the present disclosure may be configured such that a warning is issued, for example, when the table number n becomes a predetermined value smaller than the maximum value, or when the determination in S2 or S12 is YES when the table number n is the maximum value.

[0079] In the above-described embodiment, the air blower device according to the present disclosure is applied to an air conditioner. However, the present disclosure is not limited to this. That is, the present disclosure is applicable to, for example, ventilation devices in buildings and condominiums.

[0080] Furthermore, the present disclosure only needs to conform to the gist of the disclosure described in the above embodiments and is not limited to the above embodiments. Therefore, a configuration in which at least two of the above-described embodiments are combined, or a configuration in which any one of the constituent elements illustrated or described with reference numerals in the above embodiments is abolished may be used.

Description of Reference Numerals

[0081] 1... Air conditioner 2... Compressor 3... Condenser 4... Expansion valve 5... Evaporator 6... Control device 8... First blower 9... Second blower

Claims

Claims 1. An air blower device applied to an air conditioner having a compressor, a condenser, an expansion valve, and an evaporator, connected to a duct leading to a room, and blowing air that has passed through the evaporator via the duct, a compressor control unit that controls the operation of the compressor by controlling the compressor drive frequency, a blower fan, an electric motor that rotates the fan, a drive unit that drives the electric motor, a control unit that controls the electric motor using any one of a plurality of predetermined control modes, and transmits a fan drive frequency, which is a command signal for controlling the electric motor, to the drive unit, a control mode determination unit that selects a control mode to be used for controlling the electric motor from among the plurality of control modes, and is a control mode determination unit that operates at a predetermined time interval while the control unit is operating, a storage unit that stores in advance information indicating the relationship between the fan drive frequency and the air volume when the pressure loss generated in the duct is used as a parameter, an air volume detection unit that detects the air volume, In each of the plurality of control modes, the fan drive frequency is determined as a function value of the compressor drive frequency, and these functions are functions corresponding to the degree of the external static pressure, When the air volume stored in the storage unit is the assumed air volume and the fan drive frequency for the assumed air volume is the assumed frequency, The control mode determination unit determines whether the current air volume detected by the air volume detection unit belongs to a predetermined range with respect to the assumed air volume when the current fan drive frequency is the assumed frequency, and selects a function that is the control mode used for controlling the electric motor. When the current air volume is smaller than the lower limit value of the above range, a control mode with an external static pressure larger than the current set external static pressure is selected. When the current air volume is larger than the upper limit value of the above range, a control mode with an external static pressure smaller than the current set external static pressure is selected. Furthermore, when the control mode with the largest external static pressure among the "plurality of predetermined control modes" is selected, a warning is issued. An air blower device. Claims 2. An air blower device applied to an air conditioner having a compressor, a condenser, an expansion valve, and an evaporator, connected to a duct leading to a room, and blowing air that has passed through the evaporator via the duct, A compressor control unit that controls the operation of the compressor by controlling the compressor drive frequency, A fan for blowing air, An electric motor that rotates the fan, A drive unit that drives the electric motor, A control unit that controls the electric motor using any one of a plurality of predetermined control modes, and a fan control unit that transmits a fan drive frequency, which is a command signal for controlling the electric motor, to the drive unit, A control mode determination unit that selects a control mode to be used for controlling the electric motor from among the plurality of control modes, and a control mode determination unit that operates at a predetermined time interval in a state where the control unit is operating, A storage unit that stores in advance information indicating the relationship between the fan drive frequency and the power consumption of the electric motor when the pressure loss generated in the duct is used as a parameter, A power consumption detection unit that detects the power consumption of the electric motor, In each of the plurality of control modes, the fan drive frequency is determined as a function value of the compressor drive frequency, and these functions are functions according to the degree of the external static pressure, When the assumed current stored in the storage unit is used as the assumed current and the current fan drive frequency is used as the assumed frequency, The control mode determination unit determines whether the current current detected by the power consumption detection unit belongs to a predetermined range with respect to the assumed current when the current fan drive frequency is used as the assumed frequency, and selects a function that is the control mode used for controlling the electric motor. When the current current is smaller than the lower limit value of the above range, a control mode with an external static pressure larger than the current set external static pressure is selected. When the current current is larger than the upper limit value of the above range, a control mode with an external static pressure smaller than the current set external static pressure is selected. Furthermore, a blower device that issues a warning when the control mode with the largest external static pressure among the "plurality of predetermined control modes" is selected.

3. The blower device according to claim 1 or 2, wherein each of the plurality of control modes has different minimum drive frequencies and maximum drive frequencies.

4. In an air conditioner that adjusts the temperature of a room, A heat exchanger that generates cold or warm heat, The blower device according to any one of claims 1 to 3 that blows air cooled or heated by the heat exchanger, An air conditioner comprising:

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