Ceiling fan

Abstract

To provide a ceiling fan that has improved accuracy of motor current calculation even if there exist characteristic variations in an amplifier.SOLUTION: A ceiling fan includes: blades 4; a rotation motor 3 for rotating the blades 4; a voltage conversion unit 21 for converting a motor current flowing through the rotation motor 3 to a first voltage; an amplifier 23 for amplifying the first voltage to a second voltage; a voltage input unit 28 capable of inputting a predetermined voltage; and a detection unit 24 for detecting the second voltage. The ceiling fan also includes: a correction calculation unit 25 for calculation a correction voltage difference, which is a difference between the second voltage detected by the detection unit 24 when the rotation of the rotation motor 3 is stopped, and the predetermined voltage is input, and a theoretical value of the second voltage; a storage unit 29 for storing the correction voltage difference; and an inverse operation unit 26 for inversely operating the motor current flowing through the rotation motor 3 on the basis of the correction voltage difference, the second voltage detected by the detection unit 24, an amplification ratio of the amplifier 23, and a resistance value of the voltage conversion unit 21.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a ceiling fan. [Background technology]

[0002] BACKGROUND ART Ceiling fans that are attached to ceilings are known. For example, Patent Document 1 discloses a ceiling fan equipped with a motor for rotating blades. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-109580 Summary of the Invention [Problem to be solved by the invention]

[0004] The distance from the ceiling to the blades of a ceiling fan varies depending on the installation environment. When the distance from the ceiling to the blades of the ceiling fan changes, the air resistance on the blades changes as the fan rotates. Therefore, if constant motor speed control is used, the motor may break down depending on the installation environment, so constant motor current control is preferable.

[0005] Constant motor current control requires accurate calculation of the motor current. One method for calculating the motor current is to convert the motor current into a voltage, amplify the converted voltage, detect the amplified voltage, and calculate the motor current from the detected voltage.

[0006] However, there are variations in the characteristics of the amplifier, which is an amplifier unit for amplifying the voltage, and there is a possibility that the motor current cannot be calculated with high accuracy due to the variations in the characteristics.

[0007] SUMMARY OF THE INVENTION The present invention is intended to solve the above-mentioned conventional problems, and has an object to provide a ceiling fan that improves the accuracy of calculating the motor current even when there is variation in the characteristics of the amplifier. [Means for solving the problem]

[0008] To achieve this object, the ceiling fan of the present invention comprises blades that rotate to blow air; the second voltage amplified by the amplifier; a correction calculation unit that calculates a correction voltage difference that is the difference between the second voltage detected by the detection unit when the rotation of the rotary motor is stopped and a predetermined voltage is input to the amplifier by inputting a predetermined current, and the theoretical value of the second voltage that should be detected by the detection unit when the rotation of the rotary motor is stopped and a predetermined voltage is input to the amplifier by inputting a predetermined current, assuming that there is no characteristic variation in the amplifier; a memory unit that stores the correction voltage difference calculated by the correction calculation unit; and a back calculation unit that back calculates the motor current flowing through the rotary motor based on the correction voltage difference stored in the memory unit, the second voltage detected by the detection unit, the amplification factor of the amplifier, and the resistance value of the voltage conversion unit.

[0009] In order to achieve this object, the ceiling fan according to the present invention comprises blades that rotate to blow air; the second voltage amplified by the amplifier; a correction calculation unit that calculates a correction voltage difference that is the difference between the second voltage detected by the detection unit when the rotation of the rotary motor is stopped and the predetermined voltage is input, and the theoretical value of the second voltage that should be detected by the detection unit when the rotation of the rotary motor is stopped and the predetermined voltage is input, assuming that there is no characteristic variation in the amplifier; a memory unit that stores the correction voltage difference calculated by the correction calculation unit; and a back-calculation unit that back-calculates the motor current flowing through the rotary motor based on the correction voltage difference stored in the memory unit, the second voltage detected by the detection unit, the amplification factor of the amplifier, and the resistance value of the voltage conversion unit. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a ceiling fan that improves the accuracy of calculating the motor current even when there is variation in the characteristics of the amplifier. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a side view of a ceiling fan according to an embodiment of the present invention. [Figure 2] 1 is a schematic functional block diagram of a ceiling fan according to a first embodiment. [Figure 3] 5 is a flowchart showing a procedure for a correction voltage difference calculation process according to the first embodiment. [Figure 4] 4 is a flowchart showing the procedure of normal processing according to the first embodiment. [Figure 5] FIG. 10 is a schematic functional block diagram of a ceiling fan according to a second embodiment. [Figure 6] 10 is a flowchart showing a procedure for a correction voltage difference calculation process according to the second embodiment. [Figure 7] 10 is a flowchart showing the procedure of normal processing according to the second embodiment. [Figure 8]FIG. 10 is a schematic functional block diagram of a ceiling fan according to a fourth embodiment. [Figure 9] 10 is a flowchart showing the procedure of a first voltage correction amount setting process according to the fourth embodiment. [Figure 10] 10 is a flowchart showing the procedure of normal processing according to the fourth embodiment. [Figure 11] FIG. 10 is a schematic functional block diagram of a ceiling fan according to a fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the embodiments shown below are merely illustrative examples for embodying the technical concept of the present invention, and the present invention is not limited to the following. In particular, the materials, shapes, components, and the arrangement and relative arrangement of the components described in the embodiments are merely examples and are not intended to limit the scope of the present invention thereto. Furthermore, in each drawing, substantially identical components are designated by the same reference numerals, and redundant explanations are omitted or simplified. Furthermore, the dimensions of the components in each drawing are enlarged or reduced as appropriate to facilitate understanding. Furthermore, in each drawing, some components that are not important for explaining the embodiments are omitted.

[0013] Hereinafter, the ceiling fan will be referred to as a ceiling fan.

[0014] (Embodiment 1) First, we will explain ceiling fan A, an embodiment of the present invention. Ceiling fan A is attached to a ceiling 30 and functions as a fan that generates an upward or downward airflow by rotating blades 4. Figure 1 is a side view of ceiling fan A.

[0015] As shown in FIG. 1, the ceiling fan A includes a main body 1, a shaft 2, a rotary motor 3, blades 4, a motor shaft 5, a circuit board 6, and a rotor 7.

[0016] The body 1 acts as an outer shell that encloses the rotary motor 3 and other components.

[0017] The shaft 2 extends downward from the ceiling 30 and supports the main body 1 at its lower end.

[0018] The rotary motor 3 is a DC (Direct Current) motor that rotates the blades 4 via a rotor 7. The rotary motor 3 has an outer rotor structure that includes a stator fixed to the motor shaft 5 and a rotor that rotates around the outer periphery of the stator. The rotor 7 is fixed to the rotor.

[0019] The motor shaft 5 is a hollow rotary shaft that extends downward from the shaft 2 and supports the rotary motor 3 .

[0020] The blades 4 blow air in the vertical direction by rotation. A plurality of blades 4 are attached to the outer periphery of the rotor 7 and rotate integrally with the rotor of the rotary motor 3.

[0021] The circuit board 6 includes a drive circuit that drives the rotary motor 3 and a power supply circuit that supplies power to each circuit, including the drive circuit. The drive circuit and power supply circuit are capable of rotating the rotary motor 3, but the circuit configuration is known technology and will not be described in detail. The circuit board 6 also includes a voltage conversion unit 21, an amplifier unit 23, a voltage input unit 28, and a control unit 31, which will be described in detail below.

[0022] Next, the circuit board 6 will be described using FIG. 2. FIG. 2 is a schematic functional block diagram illustrating a ceiling fan A. Each functional block shown in FIG. 2 can be realized in hardware using one or more electronic circuits including a semiconductor integrated circuit (Integrated Circuit), an LSI (Large Scale Integration), or each circuit element component. Multiple electronic circuits may be integrated into a single chip, or may be provided on multiple chips. Multiple chips may be integrated into a single device, or may be provided on multiple devices. Each functional block is realized in software using a computer program or the like. The functional blocks here are realized by the cooperation of hardware and software. Therefore, those skilled in the art who have read this specification will understand that these functional blocks can be realized in various configurations using a combination of hardware and software.

[0023] The circuit board 6 includes a voltage conversion unit 21, an amplifier unit 23, a voltage input unit 28, and a control unit 31.

[0024] The voltage conversion unit 21 converts the motor current flowing through the rotary motor 3 into a first voltage. The voltage conversion unit 21 is a resistive component, and the first voltage is the product of the motor current and the resistance value of the resistive component. The resistive component used as the voltage conversion unit 21 generally has a small resistance value. If a resistive component with a small resistance value were not used, the motor current flowing through the rotary motor 3 would cause the resistive component (voltage conversion unit 21) to generate a large amount of heat, resulting in damage to the resistive component. An example of a small resistance value is 1.0 [Ω]. However, the resistance value may be larger or smaller than this as long as the motor current flowing through the rotary motor 3 does not cause the resistive component to be damaged.

[0025] The amplifier 23 amplifies the first voltage converted by the voltage converter 21 to generate a second voltage. The amplifier 23 is a circuit component that amplifies voltage, generally called an amplifier, and is configured with a semiconductor integrated circuit. The amplifier 23 has a preset gain, which is defined in the amplifier specifications.

[0026] Here, the amplifier serving as the amplifying unit 23 has characteristic variations, and the characteristic variations are also defined in the specifications. Amplifiers do not always achieve the target characteristic values, and some may deviate slightly from the target characteristic values. The deviation from the target characteristic values ​​is called characteristic variations.

[0027] For example, if an amplifier does not have characteristic variations, then the second voltage = first voltage × amplification factor, but if it has characteristic variations, then the second voltage = (first voltage + characteristic variations) × amplification factor. Characteristic variations can be positive or negative.

[0028] The voltage input unit 28 can input a predetermined voltage instead of the first voltage converted by the voltage conversion unit 21. In the present embodiment, the voltage input unit 28 can input the predetermined voltage to the amplifier unit 23. The predetermined voltage is generated by, for example, a power supply circuit.

[0029] The control unit 31 includes a detection unit 24 , a storage unit 29 , a correction calculation unit 25 , a reverse calculation unit 26 , a rotation control unit 20 , and an input instruction unit 32 .

[0030] The detection unit 24 detects the second voltage amplified by the amplifier unit 23. In this embodiment, the minimum value of the voltage detectable range of the detection unit 24 is greater than the first voltage. The first voltage is the product of the motor current and the resistance value of the resistive component, but as described above, the resistance value of the resistive component is small. In other words, the first voltage also has a small voltage value, and the detection unit 24 cannot detect the first voltage. By amplifying the first voltage in the amplifier unit 23 to generate the second voltage, the detection unit 24 can detect the second voltage.

[0031] The storage unit 29 is a so-called memory, and stores various values.

[0032] Correction calculation unit 25 calculates a correction voltage difference, which is the difference between the second voltage detected by detection unit 24 when rotation of rotary motor 3 is stopped and a predetermined voltage is input from voltage input unit 28, and a theoretical value of the second voltage that should be detected by detection unit 24 when rotation of rotary motor 3 is stopped and a predetermined voltage is input, assuming that there is no characteristic variation in amplifier 23. A detailed calculation method will be described later. Correction calculation unit 25 stores the calculated correction voltage difference in memory unit 29.

[0033] The reverse calculation unit 26 reverse-calculates the motor current flowing through the rotary motor 3 based on the corrected voltage difference stored in the memory unit 29, the second voltage detected by the detection unit 24, the amplification factor of the amplification unit 23, and the resistance value of the voltage conversion unit 21. Specifically, the reverse calculation unit 26 subtracts the corrected voltage difference from the second voltage, divides the subtracted value by the amplification factor, and divides the divided value by the resistance value of the voltage conversion unit 21, thereby reverse-calculating the motor current.

[0034] The rotation control unit 20 controls the rotation of the rotary motor 3 so that the motor current back-calculated by the back-calculation unit 26 becomes the target current. In other words, the rotation control unit 20 performs constant motor current control so that the motor current back-calculated by the back-calculation unit 26 becomes the target current. Constant motor current control is a known technique, so a detailed description will be omitted.

[0035] The input instruction unit 32 instructs whether or not to input a predetermined voltage via the voltage input unit 28. When the input instruction unit 32 instructs to input a predetermined voltage, the voltage input unit 28 inputs the predetermined voltage. When the input instruction unit 32 instructs not to input a predetermined voltage, the voltage input unit 28 does not input the predetermined voltage.

[0036] Here, we will explain why the inverse calculation unit 26 inversely calculates the motor current flowing through the rotary motor 3 based on the corrected voltage difference stored in the memory unit 29, the second voltage detected by the detection unit 24, the amplification factor of the amplification unit 23, and the resistance value of the voltage conversion unit 21.

[0037] In general, the motor current flowing through rotary motor 3 can be back-calculated based on the second voltage detected by detection unit 24, the amplification factor of amplifier 23, and the resistance value of voltage conversion unit 21. Specifically, the motor current flowing through rotary motor 3 can be back-calculated by dividing the second voltage by the amplification factor and then dividing the resulting value by the resistance value. This back-calculation method is defined as a conventional back-calculation method.

[0038] However, the amplifier serving as the amplifying unit 23 has variations in characteristics.

[0039] If the amplifier has negative characteristic variations, the second voltage will be smaller than the value obtained by multiplying the first voltage by the amplification factor. In other words, the motor current calculated using the conventional back-calculation method will be smaller than the current actually flowing through the rotary motor 3.

[0040] Furthermore, if the amplifier has positive characteristic variations, the second voltage will be greater than the value obtained by multiplying the first voltage by the amplification factor. In other words, the motor current calculated using the conventional back-calculation method will be greater than the current actually flowing through the rotary motor 3.

[0041] That is, in the conventional back-calculation method, the back-calculated motor current and the current actually flowing through the rotary motor 3 are different from each other because the amplifiers have variations in characteristics.

[0042] In this state, if the rotation control unit 20 performs constant motor current control so that the back-calculated motor current becomes the target current, the air volume blown from the blades 4 rotated by the rotary motor 3 may not become the target air volume. There is also a risk that a current exceeding the rated value may flow through the rotary motor 3.

[0043] However, in this embodiment, the back calculation unit 26 back-calculates the motor current flowing through the rotary motor 3 based on the corrected voltage difference stored in the memory unit 29, the second voltage detected by the detection unit 24, the amplification factor of the amplifier 23, and the resistance value of the voltage conversion unit 21. This makes it possible to suppress the discrepancy between the back-calculated motor current and the current actually flowing through the rotary motor 3, even if there is variation in the amplifier characteristics. In other words, it is possible to improve the calculation accuracy of the motor current, even if there is variation in the amplifier characteristics. This is because the corrected voltage difference is a value calculated based on the variation in the amplifier characteristics.

[0044] In this embodiment, when the rotation control unit 20 performs constant motor current control so that the back-calculated motor current becomes the target current, the air volume blown from the blades 4 rotated by the rotary motor 3 becomes the target air volume. In addition, there is no risk of a current exceeding the rated value flowing through the rotary motor 3.

[0045] The operation of ceiling fan A configured as described above will now be explained. Ceiling fan A first performs a correction voltage difference calculation process to calculate a correction voltage difference, and then performs normal processing. First, the correction voltage difference calculation process will be explained using FIG. 3. FIG. 3 is a flowchart showing the steps of the correction voltage difference calculation process according to this embodiment. In the flowchart, numbers are assigned starting with the initial S. For example, S21 indicates a processing step. However, the magnitude of the numerical value indicating the processing step does not affect the processing order.

[0046] First, the rotation control unit 20 stops the rotation of the rotary motor 3. The input instruction unit 32 instructs the voltage input unit 28 to input a predetermined voltage, and the voltage input unit 28 inputs the predetermined voltage to the amplifier unit 23 (S21). In the present embodiment, the predetermined voltage is set to 0.10 [V] as an example. The predetermined voltage is set to a voltage value such that the voltage amplified by the amplifier unit 23 falls within a voltage range detectable by the detector 24.

[0047] The amplifier 23 amplifies the predetermined voltage. That is, the predetermined voltage is amplified by the amplifier 23 to become a second voltage (S22).

[0048] The detector 24 detects the second voltage amplified by the amplifier 23 (S23). As an example, the second voltage detected by the detector 24 is set to 2.7 [V].

[0049] The correction calculation unit 25 calculates the theoretical value of the second voltage that should be detected by the detection unit 24 when the rotation of the rotary motor 3 is stopped and a predetermined voltage is input, assuming that there is no characteristic variation in the amplifier unit 23. Here, as an example, the amplification factor of the amplifier unit 23 is set to 30. The amplification factor is defined in the specifications of the amplifier and is stored in advance in the storage unit 29. The calculation formula for the theoretical value of the second voltage is Theoretical value of the second voltage =Predetermined voltage × Amplification factor of amplifier 23 =0.10×30=3.0[V] is. In other words, if there were no variation in the characteristics of the amplifier unit 23, the second voltage detected by the detector unit 24 would be 3.0 [V], but because there is variation in the characteristics of the amplifier unit 23, the second voltage detected by the detector unit 24 is 2.7 [V].

[0050] Next, the correction calculation unit 25 calculates the correction voltage difference (S24). The calculation formula is Corrected voltage difference = second voltage detected by the detection unit 24 - theoretical value of the second voltage =2.7-3.0=-0.3[V] is. The correction calculation unit 25 stores the calculated correction voltage difference in the storage unit 29 (S25). The above is the correction voltage difference calculation process.

[0051] Next, normal processing will be described with reference to Fig. 4. Fig. 4 is a flowchart showing the procedure of normal processing according to this embodiment. In normal processing according to this embodiment, input instruction unit 32 does not instruct voltage input unit 28 to input a predetermined voltage.

[0052] First, the rotation control unit 20 rotates the rotary motor 3 (S31). Here, an initial voltage that will not cause the rotary motor 3 to break down is applied to the rotary motor 3. This causes a motor current to flow through the rotary motor 3.

[0053] The voltage conversion unit 21 converts the motor current flowing through the rotary motor 3 into a first voltage (S32). The amplification unit 23 amplifies the first voltage converted by the voltage conversion unit 21 to generate a second voltage (S33).

[0054] The detection unit 24 detects the second voltage amplified by the amplification unit 23 (S34). As an example, the second voltage detected by the detection unit 24 is set to 2.7 [V].

[0055] The inverse calculation unit 26 inversely calculates the motor current flowing through the rotary motor 3 based on the corrected voltage difference, the second voltage detected by the detection unit 24, the amplification factor, and the resistance value of the voltage conversion unit 21 (S35). As an example, the resistance value of the voltage conversion unit 21 is set to 1.0 [Ω]. The specific formula for calculating the motor current inversely calculated by the inverse calculation unit 26 is: Motor current calculated by the reverse calculation unit 26 = (second voltage detected by the detection unit 24 - correction voltage difference) ÷ amplification factor ÷ resistance value of the voltage conversion unit 21 =(2.7+0.3)÷30÷1.0=0.1[A] is.

[0056] By the way, if the current actually flowing through the rotary motor 3 is 0.1 [A], then by back-calculating using the conventional method, we get Motor current back-calculated using conventional method = Second voltage detected by the detection unit 24 ÷ Amplification factor ÷ Resistance value of the voltage conversion unit 21 =2.7÷30÷1.0=0.09[A] This becomes: In other words, variations in the characteristics of amplifier 23 cause a discrepancy between the motor current back-calculated by the conventional back-calculation method and the current actually flowing through rotary motor 3. However, in this embodiment, back-calculation unit 26 corrects the second voltage detected by detector 24 with the correction voltage difference, thereby suppressing the discrepancy between the back-calculated motor current and the current actually flowing through rotary motor 3.

[0057] The rotation control unit 20 performs constant motor current control so that the motor current calculated by the reverse calculation unit 26 becomes the target current (S36). This allows the air volume blown from the blades 4 rotated by the rotary motor 3 to become the target air volume. Furthermore, it is possible to eliminate the risk of a current exceeding the rated value flowing through the rotary motor 3.

[0058] (Embodiment 2) The second embodiment will be described with reference to Fig. 5, focusing on the differences from the first embodiment. Fig. 5 is a schematic functional block diagram showing a ceiling fan in the second embodiment. The circuit board in the second embodiment is partially different from the circuit board in the first embodiment, and these differences will be described.

[0059] The circuit board 6 in the second embodiment includes a voltage conversion unit 21, a first voltage correction unit 22, an amplifier unit 23, a voltage input unit 28, and a control unit 31. That is, the circuit board 6 in the second embodiment further includes a first voltage correction unit 22 in addition to the components of the circuit board in the first embodiment.

[0060] The voltage conversion unit 21 is the same as in the first embodiment, and therefore a description thereof will be omitted.

[0061] The first voltage correction unit 22 corrects the first voltage converted by the voltage conversion unit 21 by a predetermined first voltage correction amount. The first voltage correction unit 22 is composed of, for example, a power supply and a resistance component, and the first voltage correction amount is determined by the voltage value of the power supply and the resistance value of the resistance component. The first voltage correction amount can be set arbitrarily. The first voltage correction amount is, for example, a positive number equal to or greater than the maximum value of negative characteristic variation in the amplifier unit 23.

[0062] The amplifier 23 amplifies the first voltage corrected by the first voltage correction amount by the first voltage correction unit 22 to generate a second voltage. The amplifier 23 is configured by an amplifier, as in the first embodiment.

[0063] The voltage input unit 28 can input a predetermined voltage instead of the first voltage converted by the voltage conversion unit 21. In this embodiment, the voltage input unit 28 inputs the predetermined voltage to the first voltage correction unit 22.

[0064] The control unit 31 includes a detection unit 24 , a storage unit 29 , a correction calculation unit 25 , a reverse calculation unit 26 , a rotation control unit 20 , and an input instruction unit 32 .

[0065] The detection unit 24, storage unit 29, correction calculation unit 25, rotation control unit 20, and input instruction unit 32 are the same as those in the first embodiment, and therefore their explanation will be omitted.

[0066] The reverse calculation unit 26 reverse-calculates the motor current flowing through the rotary motor 3 based on the corrected voltage difference stored in the memory unit 29, the second voltage detected by the detection unit 24, the amplification factor of the amplification unit 23, the resistance value of the voltage conversion unit 21, and the first voltage correction amount corrected by the first voltage correction unit 22. Specifically, the reverse calculation unit 26 subtracts the corrected voltage difference from the second voltage, divides the value obtained by subtracting the corrected voltage difference from the second voltage by the amplification factor, subtracts the value divided by the amplification factor by the first voltage correction amount, and divides the value obtained by subtracting the first voltage correction amount by the resistance value of the voltage conversion unit 21, thereby reverse-calculating the motor current.

[0067] The operation of a ceiling fan configured as described above will now be described. The ceiling fan according to this embodiment also first performs a corrected voltage difference calculation process to calculate a corrected voltage difference, and then performs normal processing. First, the corrected voltage difference calculation process according to this embodiment will be described using FIG. 6. FIG. 6 is a flowchart showing the steps of the corrected voltage difference calculation process according to this embodiment.

[0068] First, step S21 is performed in the same manner as in embodiment 1. In this embodiment, the predetermined voltage is set to 0.10 [V].

[0069] The first voltage correction unit 22 corrects the predetermined voltage by a predetermined first voltage correction amount (S41). Specifically, the first voltage correction unit 22 adds the first voltage correction amount to the predetermined voltage. In this embodiment, as an example, the first voltage correction amount is set to 0.02 [V]. That is, Voltage after correction by the first voltage correction unit 22 = specified voltage + first voltage correction amount =0.10+0.02=0.12[V] is.

[0070] The amplifier 23 amplifies the voltage corrected by the first voltage corrector 22 (S42). The amplified voltage becomes the second voltage.

[0071] The detection unit 24 detects the second voltage amplified by the amplification unit 23 (S43). In the present embodiment, as an example, the second voltage detected by the detection unit 24 is set to 3.3 [V].

[0072] The correction calculation unit 25 calculates the theoretical value of the second voltage that should be detected by the detection unit 24 when the rotation of the rotary motor 3 is stopped and a predetermined voltage is input, assuming that there is no characteristic variation in the amplifier unit 23. Here, the amplification factor of the amplifier unit 23 is set to 30. The calculation formula for the theoretical value of the second voltage is Theoretical value of the second voltage = (predetermined voltage + first voltage correction amount) × amplification factor of the amplifier 23 =(0.10+0.02)×30 =3.6[V]. In other words, if there were no variation in the characteristics of the amplifier unit 23, the second voltage detected by the detector unit 24 would be 3.6 [V], but because there is variation in the characteristics of the amplifier unit 23, the second voltage detected by the detector unit 24 becomes 3.3 [V].

[0073] Next, the correction calculation unit 25 calculates the correction voltage difference (S44).

[0074] The formula is: Corrected Voltage Difference = Second voltage detected by the detector 24 - Theoretical value of the second voltage =3.3-3.6=-0.3[V] is.

[0075] The correction calculation unit 25 stores the calculated correction voltage difference in the storage unit 29 (S45). The above is the correction voltage difference calculation process.

[0076] Next, normal processing in this embodiment will be described with reference to Fig. 7. Fig. 7 is a flowchart showing the procedure of normal processing according to this embodiment. In normal processing according to this embodiment, input instruction unit 32 does not instruct voltage input unit 28 to input a predetermined voltage.

[0077] First, the rotation control unit 20 rotates the rotary motor 3 (S51). Here, an initial voltage that will not cause the rotary motor 3 to break down is applied to the rotary motor 3. This causes a motor current to flow through the rotary motor 3.

[0078] The voltage conversion unit 21 converts the motor current flowing through the rotary motor 3 into a first voltage (S52).

[0079] The first voltage correction unit 22 corrects the first voltage converted by the voltage conversion unit 21 by a predetermined first voltage correction amount (S53). Specifically, the first voltage correction unit 22 adds the first voltage correction amount to the first voltage.

[0080] The amplifier 23 amplifies the first voltage corrected by the first voltage correction unit 22 by the first voltage correction amount to generate a second voltage (S54).

[0081] The detection unit 24 detects the second voltage amplified by the amplification unit 23 (S55). As an example, the second voltage detected by the detection unit 24 is set to 3.3 [V].

[0082] The inverse calculation unit 26 inversely calculates the motor current flowing through the rotary motor 3 based on the corrected voltage difference, the second voltage detected by the detection unit 24, the amplification factor, the resistance value of the voltage conversion unit 21, and the first voltage correction amount (S56). The resistance value of the voltage conversion unit 21 is set to 1.0 [Ω]. The specific formula for calculating the motor current inversely calculated by the inverse calculation unit 26 is: Motor current calculated by the reverse calculation unit 26 = ((second voltage detected by the detection unit 24 - correction voltage difference) ÷ amplification factor - first voltage correction amount) ÷ resistance value of the voltage conversion unit 21 =((3.3+0.3)÷30-0.02)÷1.0 =0.1[A] is.

[0083] The rotation control unit 20 performs constant motor current control so that the motor current calculated by the reverse calculation unit 26 becomes the target current (S57).

[0084] Now, let us assume that in the first embodiment, the amplifier serving as the amplifier unit 23 has a negative characteristic variation. For example, let us assume that the characteristic variation of the amplifier unit 23 is -0.01. In this state, if the current actually flowing through the rotary motor 3 is 0.005 [A], then: First Voltage = Current actually flowing through the rotary motor 3 × Resistance value of the voltage conversion unit 21 =0.005×1.0=0.005[V] This becomes: In the first embodiment, since the first voltage correction unit 22 is not provided, the second voltage obtained after the first voltage is amplified by the amplifier 23 is The second voltage after being amplified by the amplifier 23 = (first voltage + characteristic variation) x amplification factor =(0.005-0.01)×30 =-0.15[V] However, the second voltage does not actually become negative, and if the second voltage is a negative value in the above calculation, the second voltage after being amplified by the amplifier 23 becomes 0 [V]. In other words, the second voltage detected by the detector 24 becomes 0 [V]. Motor current back-calculated by the back-calculation unit 26 of the first embodiment = (second voltage detected by the detection unit 24 - correction voltage difference) ÷ amplification factor ÷ resistance value of the voltage conversion unit 21 =(0-(-0.3))÷30÷1.0 =0.01[A] This becomes: That is, there is a discrepancy between the back-calculated motor current and the current actually flowing through the rotary motor 3. This discrepancy occurs when the second voltage amplified by the amplifier 23 has a negative value. That is, when the current actually flowing through the rotary motor 3 is small, there is a discrepancy between the back-calculated motor current and the current actually flowing through the rotary motor 3, and therefore the air volume blown from the blades 4 rotated by the rotary motor 3 cannot be set to the target air volume.

[0085] Therefore, in this embodiment, the first voltage correction amount by first voltage correction unit 22 is set to a positive number equal to or greater than the maximum value of negative characteristic variation in amplifier unit 23. The maximum value of negative characteristic variation in amplifier unit 23 can be found by looking at the specifications of the amplifier that is amplifier unit 23. In this embodiment, the second voltage after amplification by amplifier unit 23 = (first voltage + first voltage correction amount + characteristic variation) × amplification factor. In other words, by setting the first voltage correction amount by first voltage correction unit 22 to a positive number equal to or greater than the maximum value of negative characteristic variation in amplifier unit 23, the second voltage after amplification by amplifier unit 23 in this embodiment will never be a negative value.

[0086] If the first voltage correction amount is 0.02 [V], the correction voltage difference is −0.3 [V], and the second voltage detected by the detection unit 24 is 0.45 [V]. In this state, when the inverse calculation unit 26 inversely calculates the motor current flowing through the rotary motor 3 based on the correction voltage difference, the second voltage, the amplification factor, the resistance value of the voltage conversion unit 21, and the first voltage correction amount, the result is: Motor current calculated by the reverse calculation unit 26 = ((second voltage detected by the detection unit 24 - correction voltage difference) ÷ amplification factor - first voltage correction amount) ÷ resistance value of the voltage conversion unit 21 =((0.45+0.3)÷30-0.02)÷1.0 =0.005[A] This becomes: That is, in this embodiment, even if the amplifier 23 has negative characteristic variations, it is possible to suppress the deviation between the back-calculated motor current and the current actually flowing through the rotary motor 3.

[0087] The rotation control unit 20 performs constant motor current control so that the motor current calculated by the back calculation unit 26 becomes the target current, so that the air volume blown from the blades 4 rotated by the rotary motor 3 can be set to the target air volume.

[0088] (Embodiment 3) Like embodiment 2, embodiment 3 also relates to the back-calculation of the motor current flowing through rotary motor 3. The following mainly describes the differences between embodiment 3 and embodiment 2. The schematic functional block diagram showing the ceiling fan in embodiment 3 is the same as embodiment 2. Only the setting of the first voltage correction amount differs between embodiment 3 and embodiment 2, and this difference will be described.

[0089] The first voltage correction amount may be a negative number obtained by inverting a value equal to or less than the maximum value of the positive characteristic variation in the amplifier unit 23 to a negative value.

[0090] Suppose the amplifier serving as amplifying unit 23 has positive characteristic variations. If the amplifier has positive characteristic variations and the current flowing through rotary motor 3 increases, there is a possibility that the second voltage will exceed the maximum value of the voltage detectable range of detector 24. If the second voltage exceeds the maximum value of the voltage detectable range of detector 24, the back-calculated motor current will deviate from the current actually flowing through rotary motor 3. In other words, when the current actually flowing through rotary motor 3 is large, the air volume blown from blades 4 rotated by rotary motor 3 cannot reach the target air volume.

[0091] Therefore, in this embodiment, the first voltage correction amount by first voltage correction unit 22 is set to a negative number obtained by inverting a value equal to or less than the maximum value of the positive characteristic variation in amplifier unit 23. This makes it possible to prevent the second voltage from exceeding the maximum value of the detectable range of voltage by detector 24, even when the current flowing through rotary motor 3 is large. In other words, in this embodiment, even if amplifier unit 23 has positive characteristic variation, it is possible to prevent the discrepancy between the back-calculated motor current and the current actually flowing through rotary motor 3.

[0092] The rotation control unit 20 performs constant motor current control so that the motor current calculated by the back calculation unit 26 becomes the target current, so that the air volume blown from the blades 4 rotated by the rotary motor 3 can be set to the target air volume.

[0093] (Fourth embodiment) The fourth embodiment also relates to the back-calculation of the motor current flowing through the rotary motor 3. The fourth embodiment will be explained with reference to Fig. 8, focusing on the differences from the second embodiment. Fig. 8 is a schematic functional block diagram showing a ceiling fan in the fourth embodiment. The circuit board in the fourth embodiment is partially different from the circuit board in the second embodiment, and these differences will be explained.

[0094] The circuit board 6 in the fourth embodiment includes a voltage conversion unit 21, a first voltage correction unit 22, an amplifier unit 23, a voltage input unit 28, and a control unit 31.

[0095] The voltage conversion unit 21, the amplification unit 23 and the voltage input unit 28 are the same as those in the second embodiment, and therefore the description thereof will be omitted.

[0096] First voltage correction unit 22 corrects the first voltage converted by voltage conversion unit 21 by a first voltage correction amount, but unlike embodiment 2, the first voltage correction amount can be changed. First voltage correction unit 22 can change the voltage value of the power supply and the resistance value of the resistor that are configured, thereby making it possible to change the first voltage correction amount.

[0097] The control unit 31 includes a detection unit 24, a storage unit 29, a correction calculation unit 25, a reverse calculation unit 26, a rotation control unit 20, an input instruction unit 32, and a correction amount calculation unit 33. That is, the control unit 31 further includes the correction amount calculation unit 33 from the second embodiment.

[0098] The detection unit 24, storage unit 29, correction calculation unit 25, rotation control unit 20, and input instruction unit 32 are the same as those in the first embodiment, and therefore their explanation will be omitted.

[0099] The correction amount calculation unit 33 calculates the first voltage correction amount based on the correction voltage difference and the amplification factor. The detailed calculation method will be described later. The first voltage correction unit 22 sets the first voltage correction amount calculated by the correction amount calculation unit 33 as the correction amount. In other words, the first voltage correction unit 22 sets the first voltage correction amount based on the correction voltage difference and the amplification factor.

[0100] The reverse calculation unit 26 reverse-calculates the motor current flowing through the rotary motor 3 based on the second voltage detected by the detection unit 24, the amplification factor of the amplification unit 23, and the resistance value of the voltage conversion unit 21. The detailed calculation method will be described later.

[0101] The operation of a ceiling fan configured as described above will now be described. The ceiling fan according to this embodiment first performs a first voltage correction amount setting process to set a first voltage correction amount, and then performs normal processing. First, the first voltage correction amount setting process according to this embodiment will be described with reference to FIG. 9. FIG. 9 is a flowchart showing the steps of the first voltage correction amount setting process according to this embodiment.

[0102] First, step S21 of embodiment 2 is performed. In this embodiment, the predetermined voltage is set to 0.10 [V].

[0103] The first voltage correction unit 22 corrects the predetermined voltage by the initial setting first voltage correction amount (S61). Specifically, the first voltage correction unit 22 adds the initial setting first voltage correction amount to the predetermined voltage. The initial setting first voltage correction amount can be set arbitrarily. In this embodiment, as an example, the initial setting first voltage correction amount is set to 0.02 [V]. That is, Voltage after correction by the first voltage correction unit 22 = specified voltage + initial first voltage correction amount =0.10+0.02 =0.12[V] is.

[0104] The amplifier 23 amplifies the voltage corrected by the first voltage corrector 22 (S62). The amplified voltage becomes the second voltage.

[0105] The detection unit 24 detects the second voltage amplified by the amplification unit 23 (S63). In the present embodiment, as an example, the second voltage detected by the detection unit 24 is set to 3.3 [V].

[0106] The correction calculation unit 25 calculates the theoretical value of the second voltage that should be detected by the detection unit 24 when the rotation of the rotary motor 3 is stopped and a predetermined voltage is input, assuming that there is no characteristic variation in the amplifier unit 23. Here, the amplification factor of the amplifier unit 23 is set to 30. The calculation formula for the theoretical value of the second voltage is Theoretical value of the second voltage = (predetermined voltage + first voltage correction amount) × amplification factor of the amplifier 23 =(0.10+0.02)×30 =3.6[V] is. In other words, if there were no variation in the characteristics of the amplifier unit 23, the second voltage detected by the detector unit 24 would be 3.6 [V], but because there is variation in the characteristics of the amplifier unit 23, the second voltage detected by the detector unit 24 becomes 3.3 [V].

[0107] Next, the correction calculation unit 25 calculates the correction voltage difference (S64). The calculation formula is Corrected Voltage Difference = Second voltage detected by the detector 24 - Theoretical value of the second voltage =3.3-3.6 =-0.3[V] is.

[0108] The correction amount calculation unit 33 calculates the first voltage correction amount to be set based on the correction voltage difference and the amplification factor (S65). The correction amount calculation unit 33 calculates the first voltage correction amount to be set by subtracting the value obtained by dividing the correction voltage difference by the amplification factor from zero. That is, The first voltage correction amount to be set =0-(corrected voltage difference ÷ amplification factor) =0-(-0.3÷30) =0.01[V] This becomes: Here, the value obtained by dividing the correction voltage difference by the amplification factor is the characteristic variation of the amplifier 23, and in this embodiment, the characteristic variation of the amplifier 23 is −0.01.

[0109] The first voltage correction unit 22 sets the first voltage correction amount calculated by the correction amount calculation unit 33 as the correction amount (S66). That is, the first voltage correction amount is changed from the initially set first voltage correction amount to the first voltage correction amount calculated by the correction amount calculation unit 33.

[0110] The above is the first voltage correction amount setting process.

[0111] Next, normal processing in this embodiment will be described with reference to Fig. 10. Fig. 10 is a flowchart showing the procedure of normal processing according to this embodiment. In normal processing according to this embodiment, input instruction unit 32 does not instruct voltage input unit 28 to input a predetermined voltage.

[0112] First, as in the second embodiment, step S 51. Step S Do 52.

[0113] The first voltage correction unit 22 corrects the first voltage converted by the voltage conversion unit 21 by the first voltage correction amount calculated by the correction amount calculation unit 33 (S71). Specifically, the first voltage correction unit 22 adds the first voltage correction amount calculated by the correction amount calculation unit 33 to the first voltage.

[0114] The amplifier 23 amplifies the first voltage corrected by the first voltage corrector 22 to generate a second voltage (S72).

[0115] The detection unit 24 detects the second voltage amplified by the amplification unit 23 (S73). As an example, the second voltage detected by the detection unit 24 is set to 3.0 [V].

[0116] The reverse calculation unit 26 reverse-calculates the motor current flowing through the rotary motor 3 based on the second voltage detected by the detection unit 24, the amplification factor, and the resistance value of the voltage conversion unit 21 (S74). Specifically, the reverse calculation unit 26 divides the second voltage detected by the detection unit 24 by the amplification factor, and then divides the divided value by the resistance value of the voltage conversion unit 21 to reverse-calculate the motor current. If the resistance value of the voltage conversion unit 21 is 1.0 [Ω], the motor current reverse-calculated by the reverse calculation unit 26 is Motor current calculated by the reverse calculation unit 26 = Second voltage detected by the detection unit 24 ÷ Amplification factor ÷ Resistance value of the voltage conversion unit 21 =3.0÷30÷1.0 =0.1[A] is.

[0117] Here, the inverse calculation unit 26 inversely calculates the motor current using the formula "second voltage detected by the detection unit 24 ÷ amplification factor ÷ resistance value of the voltage conversion unit 21." However, the correct formula should be "(second voltage detected by the detection unit 24 ÷ amplification factor - first voltage correction amount calculated by the correction amount calculation unit 33 - characteristic variation of the amplifier unit 23) ÷ resistance value of the voltage conversion unit 21." However, because the first voltage correction amount is changed from the initial first voltage correction amount to the first voltage correction amount calculated by the correction amount calculation unit 33 through the first voltage correction amount setting process, "- first voltage correction amount calculated by the correction amount calculation unit 33 - characteristic variation of the amplifier unit 23" becomes zero. In other words, the motor current inversely calculated by the inverse calculation unit 26 can be calculated as "second voltage detected by the detection unit 24 ÷ amplification factor ÷ resistance value of the voltage conversion unit 21."

[0118] The rotation control unit 20 performs constant motor current control so that the motor current calculated by the reverse calculation unit 26 becomes the target current (S 75 ).

[0119] Incidentally, when the characteristic variations of the amplifier, which is the amplifying unit 23, include those with positive characteristics and those with negative characteristic variations, if the first voltage correction amount is set to a fixed value as in embodiment 2 or 3, there is a possibility that the back-calculated motor current will differ from the current actually flowing through the rotary motor 3.

[0120] In this embodiment, the first voltage correction amount by the first voltage correction unit 22 can be set to the first voltage correction amount calculated by the correction amount calculation unit 33. By setting the first voltage correction amount to the first voltage correction amount calculated by the correction amount calculation unit 33, as described above, "- the first voltage correction amount calculated by the correction amount calculation unit 33 - the characteristic variation of the amplifier unit 23" becomes zero. That is, the characteristic variation of the amplifier unit 23 is absorbed by the first voltage correction amount calculated by the correction amount calculation unit 33. That is, the amplifier unit 23 can be brought into the same state as an amplifier unit 23 with no characteristic variation. In other words, in this embodiment, regardless of whether the amplifier unit 23 has negative or positive characteristic variation, it is possible to suppress the discrepancy between the back-calculated motor current and the current actually flowing through the rotary motor 3.

[0121] The rotation control unit 20 performs constant motor current control so that the motor current calculated by the back calculation unit 26 becomes the target current, so that the air volume blown from the blades 4 rotated by the rotary motor 3 can be set to the target air volume.

[0122] (Embodiment 5) The fifth embodiment also relates to the back-calculation of the motor current flowing through the rotary motor 3. The fifth embodiment will be explained with reference to Fig. 11, focusing on the differences from the first embodiment. Fig. 11 is a schematic functional block diagram showing a ceiling fan in the fifth embodiment. The circuit board in the fifth embodiment is partially different from the circuit board in the first embodiment, and these differences will be explained.

[0123] The circuit board 6 in the fifth embodiment includes a voltage conversion section 21, an amplification section 23, a current input section 27, and a control section 31. That is, the voltage input section 28 is eliminated from the circuit board in the first embodiment, and a current input section 27 is further included.

[0124] The current input unit 27 inputs a predetermined current to the voltage conversion unit 21. The predetermined current is generated, for example, by a power supply circuit and a resistor. When the predetermined current is input to the voltage conversion unit 21, a predetermined voltage is generated. As a result, the predetermined voltage is input to the amplification unit 23.

[0125] The correction calculation unit 25 of the control unit 31 calculates a correction voltage difference, which is the difference between the second voltage detected by the detection unit 24 when the rotation of the rotary motor 3 is stopped and a predetermined voltage is input to the amplifier unit 23 by inputting a predetermined current, and the theoretical value of the second voltage that should be detected by the detection unit 24 when the rotation of the rotary motor 3 is stopped and a predetermined voltage is input to the amplifier unit 23 by inputting a predetermined current, assuming that there is no characteristic variation in the amplifier unit 23.

[0126] The input instruction unit 32 of the control unit 31 instructs whether or not to input a predetermined current via the current input unit 27. When the input instruction unit 32 instructs to input a predetermined current, the current input unit 27 inputs the predetermined current. When the input instruction unit 32 instructs not to input a predetermined current, the current input unit 27 does not input a predetermined voltage.

[0127] The method of back-calculating the motor current flowing through the rotary motor 3 is the same as in embodiment 1. That is, even if the current input unit 27 is provided instead of the voltage input unit 28, the same effects as in embodiment 1 can be obtained.

[0128] Furthermore, in the second, third and fourth embodiments, a current input unit 27 may be provided instead of the voltage input unit 28. This provides the same effects as when the voltage input unit 28 is provided.

[0129] (Embodiment 6) Embodiment 6 This also relates to the back-calculation of the motor current flowing through the rotary motor 3. In the second, third and fourth embodiments, the voltage input unit 28 inputs a predetermined voltage to the first voltage correction unit 22, but the predetermined voltage may also be input to the amplification unit 23.

[0130] The correction calculation unit calculates a correction voltage difference, which is the difference between the second voltage detected by the detection unit 24 when the rotation of the rotary motor 3 is stopped and a predetermined voltage is input, and the theoretical value of the second voltage that should be detected by the detection unit 24 when the rotation of the rotary motor 3 is stopped and a predetermined voltage is input, assuming that there is no characteristic variation in the amplifier unit 23.

[0131] The method of back-calculating the motor current flowing through the rotary motor 3 is the same as in the second, third and fourth embodiments. That is, the sixth embodiment can also achieve the same effects as the second, third and fourth embodiments.

[0132] Although the present invention has been described above based on the embodiments, it goes without saying that the present invention is not limited to the above embodiments and that various modifications are possible without departing from the spirit of the present invention. Furthermore, the numerical values ​​given in the above embodiments are merely examples, and it goes without saying that the present invention is not limited to adopting the numerical values ​​used in the description of the embodiments.

[0133] (Summary of the Invention) a correction calculation unit that calculates a corrected voltage difference, which is the difference between the second voltage detected by the detection unit when the rotation of the rotary motor is stopped and a predetermined voltage is input to the amplifier by inputting a predetermined current, and the theoretical value of the second voltage that should be detected by the detection unit when the rotation of the rotary motor is stopped and a predetermined voltage is input to the amplifier by inputting a predetermined current, assuming that there is no characteristic variation in the amplifier; a memory unit that stores the corrected voltage difference calculated by the correction calculation unit; and a back-calculation unit that back-calculates the motor current flowing through the rotary motor based on the corrected voltage difference stored in the memory unit, the second voltage detected by the detection unit, the amplification factor of the amplifier, and the resistance value of the voltage conversion unit. This makes it possible to improve the accuracy of calculating the motor current even if there is variation in the characteristics of the amplifier.

[0134] The air conditioner may further include blades that rotate to blow air, a rotary motor that rotates the blades, a voltage converter that converts a motor current flowing through the rotary motor into a first voltage, an amplifier that amplifies the first voltage converted by the voltage converter to a second voltage, a voltage input unit that can input a predetermined voltage instead of the first voltage converted by the voltage converter, a detector that detects the second voltage amplified by the amplifier, a correction calculator that calculates a corrected voltage difference that is the difference between the second voltage detected by the detector when the rotary motor is stopped and the predetermined voltage is input, and a theoretical value of the second voltage that should be detected by the detector when the rotary motor is stopped and the predetermined voltage is input assuming no characteristic variation in the amplifier, a memory that stores the corrected voltage difference calculated by the correction calculator, and a back-calculator that back-calculates the motor current flowing through the rotary motor based on the corrected voltage difference stored in the memory, the second voltage detected by the detector, the amplification factor of the amplifier, and the resistance value of the voltage converter. This improves the calculation accuracy of the motor current even when there is characteristic variation in the amplifier.

[0135] The detection unit may have a minimum value in a detectable range of voltages that is greater than the first voltage, thereby improving the accuracy of calculating the motor current even when the first voltage is undetectable and there is variation in the characteristics of the amplifier unit.

[0136] The inverse calculation unit may also calculate the motor current by subtracting the correction voltage difference from the second voltage, dividing the result by the amplification factor, and then dividing the result by the resistance value, thereby improving the accuracy of calculating the motor current even if there is variation in the characteristics of the amplification unit.

[0137] The power supply may further include a first voltage correction unit that corrects the first voltage by a first voltage correction amount, and the inverse calculation unit may inversely calculate the motor current flowing through the rotary motor based on the corrected voltage difference stored in the memory unit, the second voltage detected by the detection unit, the amplification factor of the amplifier unit, the resistance value of the voltage conversion unit, and the first voltage correction amount corrected by the first voltage correction unit. This makes it possible to improve the calculation accuracy of the motor current even if there is variation in the characteristics of the amplifier unit.

[0138] The inverse calculation unit may also calculate the motor current by dividing the value obtained by subtracting the correction voltage difference from the second voltage by the amplification factor, subtracting the result by the first voltage correction amount, and dividing the result by the resistance value of the voltage conversion unit. This improves the accuracy of calculating the motor current even if there is variation in the characteristics of the amplification unit.

[0139] The first voltage correction amount may be a positive number equal to or greater than the maximum value of the negative characteristic variation in the amplifier unit, thereby improving the accuracy of calculating the motor current even if the amplifier unit has negative characteristic variation.

[0140] The first voltage correction amount may be a negative number obtained by inverting a value equal to or less than the maximum value of the positive characteristic variation in the amplifier unit, thereby improving the accuracy of calculating the motor current even if the amplifier unit has positive characteristic variation.

[0141] The motor current calculation unit may further include a first voltage correction unit that corrects the first voltage by a first voltage correction amount, the first voltage correction amount being variable, and that sets the first voltage correction amount based on the correction voltage difference and an amplification factor, and the inverse calculation unit inversely calculates the motor current flowing through the rotary motor based on the second voltage detected by the detection unit, the amplification factor of the amplification unit, and the resistance value of the voltage conversion unit. This improves the accuracy of calculating the motor current regardless of whether the amplification unit has positive or negative characteristic variations.

[0142] The inverse calculation unit may also divide the second voltage by the amplification factor and then divide the resulting value by the resistance value to calculate the motor current, thereby improving the accuracy of calculating the motor current regardless of whether the amplification unit has positive or negative characteristic variations.

[0143] A rotation control unit may also be provided that controls the rotation of the rotary motor so that the motor current calculated by the back-calculation unit becomes the target current. This allows the air volume blown from the blades rotated by the rotary motor to be the target air volume. Furthermore, it is possible to eliminate the risk of a current exceeding the rated value flowing through the rotary motor. [Industrial Applicability]

[0144] The ceiling fan according to the present invention is useful as a fan to be installed on a ceiling. [Explanation of symbols]

[0145] A Ceiling fan 1 Main unit 2 shafts 3 Rotation Motor 4 Feathers 5 Motor shaft 6 Circuit Board 7 Rotating Body 20 Rotation control section 21 Voltage conversion unit 22 First voltage correction unit 23 Amplification section 24 Detector 25 Correction calculation unit 26 Back Calculation Section 27 Current input section 28 Voltage input section 29 Memory section 30 Ceiling 31 Control Unit 32 Input instruction section 33 Correction amount calculation section

Claims

1. A blade that blows air by rotating; a rotary motor that rotates the blades; a voltage conversion unit that converts a motor current flowing through the rotary motor into a first voltage; a current input unit that inputs a predetermined current to the voltage conversion unit; an amplifier that amplifies the first voltage converted by the voltage converter to generate a second voltage; a detection unit that detects the second voltage amplified by the amplification unit; a correction calculation unit that calculates a correction voltage difference, which is the difference between the second voltage detected by the detection unit when rotation of the rotary motor is stopped and a predetermined voltage is input to the amplifier unit by inputting the predetermined current, and a theoretical value of the second voltage that should be detected by the detection unit when rotation of the rotary motor is stopped and a predetermined voltage is input to the amplifier unit by inputting the predetermined current, assuming that there is no characteristic variation in the amplifier unit; a storage unit that stores the correction voltage difference calculated by the correction calculation unit; A ceiling fan comprising a back-calculation unit that back-calculates the motor current flowing through the rotary motor based on the corrected voltage difference stored in the memory unit, the second voltage detected by the detection unit, the amplification factor of the amplification unit, and the resistance value of the voltage conversion unit.

2. A blade that blows air by rotating; a rotary motor that rotates the blades; a voltage conversion unit that converts a motor current flowing through the rotary motor into a first voltage; an amplifier that amplifies the first voltage converted by the voltage converter to generate a second voltage; a voltage input unit that can input a predetermined voltage to the amplifier unit instead of the first voltage converted by the voltage conversion unit; a detection unit that detects the second voltage amplified by the amplification unit; a correction calculation unit that calculates a correction voltage difference, which is the difference between the second voltage detected by the detection unit when the rotation of the rotary motor is stopped and the predetermined voltage is input, and a theoretical value of the second voltage that should be detected by the detection unit when the rotation of the rotary motor is stopped and the predetermined voltage is input, assuming that there is no characteristic variation in the amplifier unit; a storage unit that stores the correction voltage difference calculated by the correction calculation unit; the corrected voltage difference stored in the storage unit, and the second voltage detected by the detection unit; a reverse calculation unit that reverse-calculates the motor current flowing through the rotary motor based on the amplification factor of the amplifier unit and the resistance value of the voltage conversion unit.

3. The detection unit 3. The ceiling fan according to claim 1, wherein the minimum value of the detectable range of voltage is greater than the first voltage.

4. The inverse calculation unit subtracting the corrected voltage difference from the second voltage; Dividing the subtracted value by the amplification factor; 4. The ceiling fan according to claim 1, wherein the motor current is calculated by dividing the divided value by the resistance value.

5. a first voltage correction unit that corrects the first voltage by a first voltage correction amount, The inverse calculation unit 4. A ceiling fan according to claim 1, wherein the motor current flowing through the rotary motor is calculated based on the correction voltage difference stored in the memory unit, the second voltage detected by the detection unit, the amplification factor of the amplifier unit, the resistance value of the voltage conversion unit, and the first voltage correction amount corrected by the first voltage correction unit.

6. The inverse calculation unit Dividing a value obtained by subtracting the correction voltage difference from the second voltage by the amplification factor; The ceiling fan according to claim 5 , wherein the motor current is calculated by subtracting the first voltage correction amount from the divided value and dividing the result by the resistance value of the voltage conversion unit.

7. The ceiling fan according to claim 5 or 6, wherein the first voltage correction amount is a positive number equal to or greater than a maximum value of negative characteristic variation in the amplifier section.

8. The ceiling fan according to claim 5 or 6, wherein the first voltage correction amount is a negative number obtained by inverting a value equal to or less than a maximum value of a positive characteristic variation in the amplifier section to a negative value.

9. a first voltage correction unit that corrects the first voltage by a first voltage correction amount; the first voltage correction amount is variable; the first voltage correction unit sets the first voltage correction amount based on the correction voltage difference and the amplification factor; 4. A ceiling fan as described in any one of claims 1 to 3, wherein the back-calculation unit back-calculates the motor current flowing through the rotary motor based on the second voltage detected by the detection unit, the amplification factor of the amplification unit, and the resistance value of the voltage conversion unit.

10. The ceiling fan according to claim 9 , wherein the inverse calculation unit divides the second voltage by the amplification factor and then divides the divided value by the resistance value to thereby calculate the motor current.

11. The ceiling fan according to claim 1 , further comprising a rotation control unit that controls rotation of the rotary motor so that the motor current back-calculated by the back-calculation unit becomes a target current.

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