Blower and ventilation device

Abstract

Provided is a blower, in which the modes for operating a DC motor by means of a control device include a normal operation mode and a correction data acquisition mode. In the correction data acquisition mode, the control device inputs an output instruction to the DC motor and calculates correction data on the basis of the value of the output instruction input to the DC motor and the actual output value of the DC motor. In the normal operation mode, the control device uses, as the value of the output instruction, a corrected instruction value which is obtained by correcting, using the correction data, the value of the output instruction in reference instruction data.

Description

Fans and ventilation equipment

[0001] The present disclosure relates to a blower and a ventilation device.

[0002] In a conventional ventilation fan air volume control device, the motor rank is selected according to the rotation speed of the DC motor for a certain applied voltage. A table storage unit stores a data table according to the motor rank. The data table shows the relationship between the applied voltage and the rotation speed. The air volume control unit controls the air volume based on the set air volume and the data table (see, for example, Patent Document 1).

[0003] Patent No. 4797642

[0004] In conventional ventilation fan air volume control devices such as those described above, even if the motor rank is the same, variations in the DC motor and drive circuit between products cause differences in the actual motor output relative to the output command, which results in variations in the air volume relative to the output command.

[0005] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a blower and a ventilation device that can suppress variations in air volume between products.

[0006] The blower according to the present disclosure includes a fan, a DC motor that drives the fan, and a control device that controls the DC motor by inputting an output instruction to the DC motor, and the operation modes of the DC motor controlled by the control device include a normal operation mode and a correction data acquisition mode, and the control device stores reference instruction data that indicates the relationship between the output instruction value and the output value of the DC motor relative to the output instruction value, and in the correction data acquisition mode, the control device inputs the output instruction to the DC motor and calculates correction data based on the output instruction value input to the DC motor and the actual output value of the DC motor, and in the normal operation mode, uses a corrected instruction value, which is a value obtained by correcting the output instruction value in the reference instruction data using the correction data, as the output instruction value.

[0007] According to the present disclosure, variations in air volume between products can be suppressed.

[0008] FIG. 2 is a block diagram showing a schematic configuration of a blower used in a ventilation device according to embodiment 1. FIG. 3 is a graph showing output values ​​relative to output instruction values ​​when correction processing is not performed by the control device main body of FIG. 1. FIG. 4 is a graph showing output values ​​relative to output instruction values ​​when correction processing is performed by the control device main body of FIG. 1. FIG. 5 is a flowchart showing correction data acquisition processing by the control device main body of FIG. 1. FIG. 6 is a flowchart showing a first modified example of correction data acquisition processing by the control device main body of FIG. 1. FIG. 7 is a flowchart showing a second modified example of correction data acquisition processing by the control device main body of FIG. 1. FIG. 8 is a configuration diagram showing a first example of a processing circuit that realizes each function of the control device main body of embodiment 1. FIG. 9 is a configuration diagram showing a second example of a processing circuit that realizes each function of the control device main body of embodiment 1.

[0009] Hereinafter, embodiments will be described with reference to the drawings. Embodiment 1. Fig. 1 is a block diagram showing the general configuration of a blower used in a ventilation device according to embodiment 1. In the figure, the blower includes a fan 11, a DC motor 12, and a control device 13.

[0010] The DC motor 12 drives the fan 11 to generate an airflow. The control device 13 controls the DC motor 12 by inputting an output instruction to the DC motor 12.

[0011] The control device 13 includes a control device main body 14, an output instruction circuit 15, and an output detection circuit 16. The control device main body 14 includes, for example, a microcomputer. The control device main body 14 also includes, as functional blocks, a storage unit 17, a calculation unit 18, and a mode switching unit 19.

[0012] The storage unit 17 stores reference instruction data, which is data indicating the relationship between the value of an output instruction for the DC motor 12 and the output value of the DC motor 12 relative to the value of the output instruction.

[0013] The output instruction value is an instruction value corresponding to the volume of air to be generated by the fan 11. In the first embodiment, the output value is the rotation speed of the DC motor 12. The reference instruction data is stored in advance in the control device main body 14 for each model of ventilation device.

[0014] The calculation unit 18 calculates the value of the output instruction. The output instruction circuit 15 inputs an output instruction to the DC motor 12 according to the calculation result by the calculation unit 18. The output detection circuit 16 detects the output value of the DC motor 12. The memory unit 17 stores the output value detected by the output detection circuit 16.

[0015] The operation modes of the DC motor 12 controlled by the control device 13 include a normal operation mode and a correction data acquisition mode. The mode switching unit 19 switches the operation mode.

[0016] In the correction data acquisition mode, the control device 13 inputs an output instruction to the DC motor 12 and calculates correction data based on the value of the output instruction input to the DC motor 12 and the actual output value of the DC motor 12 .

[0017] In the normal operation mode, the control device 13 uses, as the value of the output instruction, a corrected instruction value obtained by correcting the value of the output instruction in the reference instruction data using the correction data.

[0018] In the first embodiment, the control device main body 14 stores a reference relational expression as reference indication data. The control device main body 14 also calculates an actual relational expression as correction data. In the normal operation mode, the control device main body 14 calculates a corrected indication value based on the reference relational expression and the actual relational expression.

[0019] The reference relational expression shows the relationship between the output instruction value and the output value in a reference product. The actual measurement relational expression shows the relationship between the output instruction value and the output value in a target product. The target product is the ventilation device in embodiment 1. The reference product is a product for which performance evaluation was performed to set specification values ​​for the target product.

[0020] The reference relational equation and the actual measurement relational equation are each a linear function. That is, the output value is proportional to the value of the output instruction. If the value of the output instruction is γ and the output value is N, the reference relational equation and the actual measurement relational equation can be expressed as follows:

[0021] N = α base ×γ+β base ...Reference relation

[0022] N = α × γ + β ... measured relational expression

[0023] In the correction data acquisition mode, the control device main body 14 calculates the slope α and intercept β of the straight line indicated by the actual measurement relational expression from two or more output values ​​obtained by two or more different output instructions.

[0024] In the control device main body 14, a first set value IA and a second set value IB are set as output instruction values ​​to be input to the DC motor 12 in the correction data acquisition mode. That is, the memory unit 17 stores the first set value IA and the second set value IB. The second set value IB is a value greater than the first set value IA.

[0025] The slope α and intercept β in the measured relational equation vary depending on the individual target product. Therefore, if the output instruction value γ required to obtain the desired output value N in the reference product is input directly into the measured relational equation, the resulting output value N will differ from N in the reference relational equation. In order to make the output value N in the measured relational equation the same as the output value N in the reference relational equation, the output instruction value input into the measured relational equation needs to be corrected to the corrected instruction value δ.

[0026] α×δ+β=α base ×γ+β base The corrected indication value δ that satisfies the above is calculated by the following correction formula:

[0027] δ = (α base ×γ+β base -β) / α

[0028] The control device main body 14 is set with an upper limit rotation speed Nhigh as the upper limit of the output value N. The control device main body 14 is also set with a lower limit rotation speed Nlow as the lower limit of the output value N. The storage unit 17 stores the upper limit rotation speed Nhigh and the lower limit rotation speed Nlow.

[0029] In the correction data acquisition mode, when the output value N is equal to or less than the lower limit rotation speed Nlow, the control device main body 14 increases the value of the output instruction until the output value N becomes greater than the lower limit rotation speed Nlow. In addition, in the correction data acquisition mode, when the output value N is equal to or greater than the upper limit rotation speed Nhigh, the control device main body 14 decreases the value of the output instruction until the output value N becomes smaller than the upper limit rotation speed Nhigh.

[0030] Specifically, a first instruction value IAc, a second instruction value IBc, a first determination value OAj, a second determination value OBj, and a set correction amount are set in the control device main body 14. That is, the storage unit 17 stores the first instruction value IAc, the second instruction value IBc, the first determination value OAj, the second determination value OBj, and the set correction amount.

[0031] The first instruction value IAc is a value greater than the first set value IA. The second instruction value IBc is a value smaller than the second set value IB. The second instruction value IBc is also a value greater than the first instruction value IAc.

[0032] The first determination value OAj is a value greater than the lower limit rotation speed Nlow, and the second determination value OBj is a value smaller than the upper limit rotation speed Nhigh.

[0033] When the output value N is equal to or lower than the lower limit rotation speed Nlow, or when the output value N is equal to or higher than the upper limit rotation speed Nhigh, the control device main body 14 selects the first instruction value IAc and the second instruction value IBc as the output instruction values.

[0034] The control device main body 14 then decreases or increases the first instruction value IAc by the set correction amount so that the output value OAc at the first instruction value IAc becomes the same as the first determination value OAj. The control device main body 14 also decreases or increases the second instruction value IBc by the set correction amount so that the output value OBc at the second instruction value IBc becomes the same as the second determination value OBj.

[0035] The control device main body 14 stores the first instruction value IAc when the output value OAc becomes equal to the first determination value OAj, and the second instruction value IBc when the output value OBc becomes equal to the second determination value OBj. The control device main body 14 then calculates an actual measurement relational expression from the stored first instruction value IAc, the stored second instruction value IBc, the first determination value OAj, and the second determination value OBj.

[0036] Furthermore, if the correction data has not been calculated when the DC motor 12 starts operating in the normal operation mode, the control device main body 14 automatically starts operating the DC motor 12 in the correction data acquisition mode. After calculating the correction data, the control device main body 14 starts operating the DC motor 12 in the normal operation mode.

[0037] The control device main body 14 can also receive an external command to start the correction data acquisition mode. The command is input, for example, by operating a reset switch. When the control device main body 14 receives an external command to start the correction data acquisition mode, it starts operating the DC motor 12 in the correction data acquisition mode. The control device main body 14 then updates the correction data after calculating it.

[0038] In addition, in the correction data acquisition mode, the control device main body 14 closes the air intake and exhaust ports, thereby closing the flow path of the airflow generated by the fan 11 .

[0039] Fig. 2 is a graph showing output values ​​relative to output instruction values ​​when correction processing is not performed by the control device main body 14 of Fig. 1. Fig. 3 is a graph showing output values ​​relative to output instruction values ​​when correction processing is performed by the control device main body 14 of Fig. 1.

[0040] 2 and 3, the solid line indicates the output value for the reference product. The dotted line indicates the output value for the target product A. The dashed-dotted line indicates the output value for the target product B. The circles on the solid line, the squares on the dotted line, and the triangles on the dashed-dotted line each indicate the output command value when attempting to obtain the same air volume F1.

[0041] 2, the output instruction value corresponding to the air volume F1 is the same for the reference product, target product A, and target product B. Therefore, due to variations in the DC motor 12, output instruction circuit 15, etc., the output values ​​for target product A and target product B are different from the output value for the reference product. Therefore, variations occur in the air volumes generated between the reference product, target product A, and target product B.

[0042] 3, the correction process corrects the output instruction values ​​corresponding to the air volume F1 for the target product A and the target product B to values ​​different from the output instruction value corresponding to the air volume F1 for the reference product. As a result, the output values ​​for the target product A and the target product B are the same as the output values ​​for the reference product. Therefore, the variation in the air volumes generated by the reference product, target product A, and target product B is suppressed.

[0043] Fig. 4 is a flowchart showing the correction data acquisition process by the control device main body 14 of Fig. 1. When the operation mode is switched to the correction data acquisition mode, the control device main body 14 starts the correction data acquisition process of Fig. 4.

[0044] When the correction data acquisition process is started, the control device main body 14 selects the first set value IA as the value of the output instruction in step S101. When the output instruction value is selected by the control device main body 14, the output instruction circuit 15 inputs an output instruction corresponding to the output instruction value to the DC motor 12. That is, a voltage corresponding to the output instruction value is applied to the DC motor 12.

[0045] Next, in step S102, the control device main body 14 obtains and stores the output value OA from the output detection circuit 16. The output value OA is the number of rotations of the DC motor 12 at the first set value IA.

[0046] Next, in step S103, the control device main body 14 determines whether the output value OA is greater than the lower limit rotation speed Nlow.

[0047] If the output value OA is greater than the lower limit rotation speed Nlow, the control device main body 14 selects the second set value IB as the value of the output instruction in step S104.

[0048] Next, in step S105, the control device main body 14 acquires and stores the output value OB from the output detection circuit 16. The output value OB is the rotation speed of the DC motor 12 at the second set value IB.

[0049] Next, in step S106, the control device main body 14 determines whether the output value OB is less than the upper limit rotation speed Nhigh.

[0050] If the output value OB is less than the upper limit rotation speed Nhigh, the control device main body 14 calculates a correction formula for calculating the corrected command value δ in step S107, and ends the process.

[0051] At this time, the control device main body 14 calculates the slope α and intercept β in the actual measurement relational equation for the target product based on the first set value IA, the second set value IB, the output value OA, and the output value OB.

[0052] Specifically, the slope α is calculated by α = (OB - OA) / (IB - IA). The intercept β is calculated by β = OB - α × IB or β = OA - α × IA. Then, a correction equation is calculated from the reference relational equation and the measured relational equation.

[0053] If it is determined in step S103 that the output value OA is equal to or less than the lower limit rotation speed Nlow, the control device main body 14 selects the first instruction value IAc as the value of the output instruction in step S111. Also, if it is determined in step S106 that the output value OB is equal to or greater than the upper limit rotation speed Nhigh, the control device main body 14 proceeds to the process of step S111.

[0054] After selecting the first instruction value IAc, in step S112, the control device main body 14 obtains and stores the output value OAc from the output detection circuit 16. The output value OAc is the rotation speed of the DC motor 12 at the first instruction value IAc.

[0055] Thereafter, in step S113, the control device main body 14 determines whether the output value OAc is equal to the first determination value OAj. At this time, if the difference between the output value OAc and the first determination value OAj is within a set range, the control device main body 14 may determine that the output value OAc is equal to the first determination value OAj.

[0056] If it is determined that the output value OAc is the same as the first determination value OAj, the control device main body 14 selects the second instruction value IBc as the value of the output instruction in step S114.

[0057] After selecting the second instruction value IBc, in step S115, the control device main body 14 obtains and stores the output value OBc from the output detection circuit 16. The output value OBc is the rotation speed of the DC motor 12 at the second instruction value IBc.

[0058] Thereafter, in step S116, the control device main body 14 determines whether the output value OBc is equal to the second determination value OBj. At this time, if the difference between the output value OBc and the second determination value OBj is within a set range, the control device main body 14 may determine that the output value OBc is equal to the second determination value OBj.

[0059] If it is determined that the output value OBc is equal to the second determination value OBj, the control device main body 14 calculates a correction formula in step S107 and ends the process.

[0060] At this time, the control device main body 14 calculates the slope α and intercept β in the actual measurement relational equation of the target product based on the first indication value IAc, the second indication value IBc, the first determination value OAj, and the second determination value OBj.

[0061] Note that the output value OAc determined to be the same as the first determination value OAj may be used instead of the first determination value OAj, and the output value OBc determined to be the same as the second determination value OBj may be used instead of the second determination value OBj.

[0062] If it is determined in step S113 that the output value OAc is not equal to the first determination value OAj, the control device main body 14 determines in step S121 whether the output value OAc is greater than the first determination value OAj.

[0063] If the output value OAc is greater than the first determination value OAj, the control device main body 14 decreases the first instruction value IAc by the set correction amount in step S122. If the output value OAc is smaller than the first determination value OAj, the control device main body 14 increases the first instruction value IAc by the set correction amount in step S123.

[0064] If the first instruction value IAc has been decreased or increased, the control device main body 14 returns to the process of step S112. That is, the control device main body 14 acquires the output value OAc at the decreased or increased first instruction value IAc. Then, in step S113, the control device main body 14 again determines whether the output value OAc is the same as the first determination value OAj.

[0065] If it is determined in step S116 that the output value OBc is not equal to the second determination value OBj, the control device main body 14 determines in step S131 whether the output value OBc is greater than the second determination value OBj.

[0066] If the output value OBc is greater than the second determination value OBj, the control device main body 14 decreases the second instruction value IBc by the set correction amount in step S132. If the output value OBc is smaller than the second determination value OBj, the control device main body 14 increases the second instruction value IBc by the set correction amount in step S133.

[0067] If the second instruction value IBc is decreased or increased, the control device main body 14 returns to the process of step S115. That is, the control device main body 14 acquires the output value OBc at the second instruction value IBc after the decrease or increase. Then, in step S116, the control device main body 14 again determines whether the output value OBc is the same as the second determination value OBj.

[0068] If it is determined that the output value OAc is equal to the first determination value OAj and the output value OBc is equal to the second determination value OBj, the control device 13 calculates a correction formula in step S107 and ends the process.

[0069] In such a blower and ventilation device, the operation modes of the DC motor 12 controlled by the control device 13 include a normal operation mode and a correction data acquisition mode. In the correction data acquisition mode, the control device 13 inputs an output instruction to the DC motor 12 and calculates correction data based on the value of the output instruction input to the DC motor 12 and the actual output value of the DC motor 12. In the normal operation mode, the control device 13 uses, as the value of the output instruction, a corrected instruction value δ, which is a value obtained by correcting the value of the output instruction in the reference instruction data using the correction data.

[0070] Therefore, it is possible to suppress variations in air volume between products even if there are variations in the DC motor 12, drive circuit, etc. Furthermore, compared to when air volume is controlled using a static pressure sensor, a static pressure sensor is not required, which reduces costs.

[0071] The control device 13 also stores a reference relational equation as reference indication data. In the correction data acquisition mode, the control device 13 calculates an actual measurement relational equation. In the normal operation mode, the control device 13 calculates a corrected indication value δ based on the reference relational equation and the actual measurement relational equation. Therefore, the corrected indication value δ can be calculated with a simple configuration, and variations in air volume between products can be easily suppressed.

[0072] The corrected indication value δ is calculated using the correction formula δ = (α base ×γ+β base -β) / α. Therefore, with a simple calculation, it is possible to easily suppress variations in air volume for each product.

[0073] In the correction data acquisition mode, the control device 13 calculates the slope α and intercept β of the measured relational expression from two or more output values ​​obtained by two or more different output instructions, so that the measured relational expression can be easily calculated through simple processing.

[0074] Furthermore, in the correction data acquisition mode, when the output value is equal to or less than the lower limit rotation speed Nlow, the control device 13 increases the value of the output instruction until the output value exceeds the lower limit rotation speed Nlow. Furthermore, in the correction data acquisition mode, when the output value is equal to or greater than the upper limit rotation speed Nhigh, the control device 13 decreases the value of the output instruction until the output value becomes smaller than the upper limit rotation speed Nhigh.

[0075] Therefore, even if there is a large variation in the products, the variation in the air volume between products can be easily suppressed.

[0076] Furthermore, if the correction data has not been calculated when the DC motor 12 starts operating in the normal operation mode, the control device 13 automatically starts operating the DC motor 12 in the correction data acquisition mode. After calculating the correction data, the control device 13 starts operating the DC motor 12 in the normal operation mode.

[0077] This allows correction data to be obtained more reliably when the ventilation device is first turned on, and makes it possible to reduce variations in air volume between products from the first time the ventilation device is operated.

[0078] Furthermore, when the control device 13 receives an external instruction to start the correction data acquisition mode, it starts the operation of the DC motor 12 in the correction data acquisition mode, and updates the correction data after calculating it.

[0079] This allows the correction data to be updated as needed, such as when the DC motor 12 is replaced or when it is determined that the correction data needs to be updated, and makes it possible to suppress variations in air volume between products over the long term.

[0080] In addition, in the correction data acquisition mode, the control device 13 closes the flow path of the airflow generated by the fan 11. As a result, the air volume of the ventilation device is set to 0 m ３ / h, which maximizes the external static pressure, making it possible to suppress fluctuations in external static pressure due to differences in loss resistance in the duct connected to the ventilation system. This allows correction control of the target product under the same conditions as the reference product, enabling more accurate suppression of variation.

[0081] In this case, an operator may close at least one of the intake and exhaust ports of the ventilation device using tape, a shielding plate, a damper inside the device, or the like.

[0082] Fig. 5 is a flowchart showing a first modified example of the correction data acquisition process by the control device main body 14 of Fig. 1. In the first modified example, the processes of steps S103 and S106 in Fig. 4 are omitted. Accordingly, in the first modified example, the processes from step S111 onwards are also omitted.

[0083] If the variations between products are small and do not exceed the range of linear approximation, the process of adjusting the output instruction value may be omitted, as shown in FIG.

[0084] Fig. 6 is a flowchart showing a second modified example of the correction data acquisition process by the control device main body 14 of Fig. 1. In the second modified example, when the correction data acquisition process is started, the process of step S111 in Fig. 4 is started. Therefore, the processes from step S101 to step S106 in Fig. 4 are omitted.

[0085] When there is a large variation between products and the range of linear approximation cannot be determined, output adjustment may be performed from the beginning based on the first determination value OAj and the second determination value OBj, as shown in FIG.

[0086] The output value of the DC motor is not limited to the number of rotations of the DC motor 12, but may be, for example, the current value of the DC motor 12.

[0087] The measured relational expression may also be calculated from data of output values ​​obtained by continuously changing the value of the output instruction within a set range, for example.

[0088] The reference instruction data may be stored as a reference data table in the control device 13. The relationship between the corrected instruction value and the output value may be stored as a corrected data table in the control device 13.

[0089] The blower may also be a blower used for purposes other than ventilation equipment.

[0090] Furthermore, each function of the control device main body 14 of the first embodiment is realized by a processing circuit. Fig. 7 is a configuration diagram showing a first example of a processing circuit that realizes each function of the control device main body 14 of the first embodiment. The processing circuit 100 of the first example is dedicated hardware.

[0091] The processing circuit 100 may be, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or a combination thereof. Each function of the control device main body 14 may be realized by a separate processing circuit 100, or all functions may be realized by the processing circuit 100.

[0092] 8 is a configuration diagram showing a second example of a processing circuit that realizes each function of the control device main body 14 of embodiment 1. The processing circuit 200 of the second example includes a processor 201 and a memory 202.

[0093] In the processing circuit 200, each function of the control device main body 14 is realized by software, firmware, or a combination of software and firmware. The software and firmware are written as programs and stored in the memory 202. The processor 201 realizes each function by reading and executing the programs stored in the memory 202.

[0094] The programs stored in memory 202 can be said to cause the computer to execute the procedures or methods of the above-mentioned components. Here, memory 202 refers to non-volatile or volatile semiconductor memory such as RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable Read Only Memory), and EEPROM (Electrically Erasable and Programmable Read Only Memory). Magnetic disks, flexible disks, optical disks, compact disks, minidisks, DVDs, and the like also fall under memory 202.

[0095] It should be noted that some of the functions of the above-described units may be realized by dedicated hardware, and other parts may be realized by software or firmware.

[0096] In this way, the processing circuit can realize the functions of each of the above-mentioned units by hardware, software, firmware, or a combination of these.

[0097] 11 Fan, 12 DC motor, 13 Control device.

Claims

1. fan, A DC motor for driving the aforementioned fan, and A control device that controls the DC motor by inputting an output command to the DC motor. Equipped with, The operating modes of the DC motor by the control device include a normal operating mode and a correction data acquisition mode. The control device stores reference instruction data that shows the relationship between the value of the output instruction and the output value of the DC motor relative to the value of the output instruction. The control device is In the correction data acquisition mode, the output instruction is input to the DC motor, and correction data is calculated based on the value of the output instruction input to the DC motor and the actual output value of the DC motor. In the normal operation mode, the blower uses a corrected instruction value as the value of the output instruction, which is the value obtained by correcting the value of the output instruction in the reference instruction data with the correction data.

2. The control device stores a reference relation as reference instruction data. The control device is In the correction data acquisition mode, a measured relational expression is calculated that shows the actual relationship between the output instruction value and the output value. The blower according to claim 1, which calculates the corrected indicated value based on the reference relation and the measured relation in the normal operating mode.

3. The aforementioned reference relation and the aforementioned measured relation are both linear functions. If the value of the output instruction is γ and the output value is N, The aforementioned reference relation is, N = αbase × γ + βbase It is represented as, The aforementioned experimental relation is, N = α × γ + β It is represented as, The corrected indicated value δ is, δ=(αbase×γ+βbase−β) / α The blower according to claim 2, obtained by the above method.

4. The blower according to claim 3, wherein the control device calculates the slope α and intercept β in the measured relational expression from two or more output values ​​obtained by two or more different output instructions in the correction data acquisition mode.

5. The control device has upper and lower limits set for the output value. In the correction data acquisition mode, the control device, If the output value is less than or equal to the lower limit, the value of the output instruction is increased until the output value is greater than the lower limit. The blower according to claim 4, wherein if the output value is greater than or equal to the upper limit, the output instruction value is reduced until the output value is less than the upper limit.

6. The blower according to claim 1, wherein the control device automatically starts operation of the DC motor in the correction data acquisition mode if the correction data has not been calculated when the DC motor is started in the normal operation mode, and starts operation of the DC motor in the normal operation mode after the correction data has been calculated.

7. The blower according to claim 1, wherein the control device, upon receiving an instruction from an external source to start the correction data acquisition mode, starts operating the DC motor in the correction data acquisition mode, and updates the correction data after calculating the correction data.

8. Blower according to any one of claims 1 to 7 A ventilation system equipped with the following features.

9. The ventilation device according to claim 8, wherein the control device closes the airflow path of the fan in the correction data acquisition mode.