JPWO2016042729A1 - Ceiling fan - Google Patents

Abstract

It is a ceiling fan (1) carrying a brushless DC motor (10). The ceiling fan (1) includes a duty instruction unit (6) for instructing an ON / OFF duty of PWM control of the switching element, and a motor current detection unit (14) for detecting a current flowing in the drive coil (2) of the brushless DC motor. ). And in this ceiling fan (1), the duty instruction | indication value of a duty instruction | indication part (6) is determined by the detected value of this motor current detection part (14). By adopting this configuration, the ceiling fan (1) that can blow the fan with a constant torque with the maximum performance is obtained without being affected by the change in the distance between the blade and the ceiling due to the installation state of the ceiling fan (1). It is done.

Description

  The present invention relates to a ceiling fan equipped with a brushless DC motor for driving a fan.

  In recent years, ceiling fans have been required to be equipped with a DC motor in order to reduce power consumption. Among them, there is a demand for a ceiling fan that reduces power consumption while maintaining the maximum blowing performance without being affected by the installation state.

  Conventionally, this type of ceiling fan has a configuration disclosed in Patent Document 1.

  Hereinafter, the ceiling fan will be described with reference to FIG.

  As shown in FIG. 12, the brushless DC motor 100 includes a stator winding 114 (U, V, W), and a rotor 107 having N pole and S pole permanent magnets alternately applied to eight poles on the surface. It consists of three position detection elements 102a, 102b, 102c. These position detection elements 102 a, 102 b, 102 c are, for example, hall sensors, and are mounted on the electric circuit board 101.

  The position detection elements 102a, 102b, and 102c convert the change of the magnetic pole when the permanent magnet of the rotor 107 changes from the N pole to the S pole, and from the S pole to the N pole into H and L electrical signals, and position detection signals Is input to the rotation speed detector 109.

  The rotation speed detection unit 109 detects the rotation speed of the brushless DC motor 100 from the input position detection signal. The position detection signal is input to the time interval measurement unit 103 of the rotation speed detection unit 109. The time interval measuring unit 103 measures the time interval from when one signal of the position detection signal changes to when the other signal changes, so that one rotation of the mechanical angle of the rotor 107, that is, 12 Saving time intervals.

  The time interval average unit 104 of the rotation speed detection unit 109 obtains an average value of 12 time intervals stored by the time interval measurement unit 103.

  The rotational speed feedback unit 110 compares a predetermined target rotational speed with the rotational speed detected by the rotational speed detection unit 109, and changes the DC voltage applied to the stator winding according to the rotational speed difference. The signal is output to the DC voltage changing unit 112.

  The DC voltage changing unit 112 performs PWM modulation based on a signal for changing the DC voltage applied to the stator winding output from the rotation speed feedback unit 110, and outputs the result to the drive signal generating unit 105.

  The drive signal generator 105 captures changes in the position detection signals of the three position detection elements 102a, 102b, and 102c, and each of the stator windings U, V, and W has a predetermined direction according to the state of the position detection signal at that time. Energize sequentially in the order. At the same time, a signal for changing the DC voltage applied to the stator windings U, V, and W is output to the drive unit 106 based on the PWM modulated signal output from the DC voltage changing unit 112.

  The rotation speed detection unit 109, the rotation speed feedback unit 110, the DC voltage changing unit 112, and the drive signal generation unit 105 are built in the microcomputer 108.

  The drive unit 106 converts the switching element of the switching unit 113 into a signal for turning on and off based on the signal output from the drive signal generation unit 105 built in the microcomputer 108.

  The switching unit 113 is connected to the DC power source 111 and includes six switching elements Q1, Q2, Q3, Q4, Q5, and Q6 and six free-wheeling diodes D1, D2, D3, D4, D5, and D6. Then, the switching unit 113 sequentially energizes the stator windings U, V, and W at a predetermined timing, changes the DC voltage of the DC power source 111 to apply to the stator windings U, V, and W, and brushlessly. The DC motor 100 is rotated.

The rotation speed feedback unit 110 compares the predetermined target rotation speed Nm with the rotation speed NT detected by the time interval averaging unit 104 of the rotation speed detection unit 109,
Nd = NT-Nm
Thus, the rotational speed difference Nd is obtained.

Assuming that the change rate of the voltage corresponding to a predetermined rotation speed difference Nd is gain A and the DC voltage applied to the stator winding is V, the voltage Vd for changing the DC voltage with respect to the rotation speed difference Nd is ,
Vd = Nd × A
Ask for.

  When the rotational speed NT is decreased with respect to the target rotational speed Nm and the rotational speed difference Nd is increased, the voltage is increased by a voltage Vd to be changed with respect to the DC voltage applied to the stator windings U, V, and W. . Thereby, the rotational speed is controlled so as to approach the target rotational speed Nm. Further, when the rotational speed NT is increased with respect to the target rotational speed Nm and the rotational speed difference Nd is increased, the voltage is changed by the voltage Vd to be changed with respect to the DC voltage applied to the stator windings U, V, and W. Decrease. Thereby, the rotational speed is controlled so as to approach the target rotational speed Nm. As described above, control is performed so that the rotation speed is constant at the target rotation speed.

Japanese Patent No. 4649934

  A ceiling fan according to one aspect of the present invention includes a brushless DC motor, an inverter circuit, a drive logic control unit, a duty instruction unit, and a motor current detection unit. The brushless DC motor includes a drive coil. The inverter circuit includes an upper stage and a lower stage, and is bridge-connected by a plurality of switching elements. The drive logic control unit performs PWM control on the DC voltage applied to the inverter circuit and also controls drive logic for sequentially energizing the drive coil. A duty instruction | indication part instruct | indicates PWM control ON / OFF duty. The motor current detection unit detects a current flowing through the drive coil. And a duty instruction | indication part determines a duty instruction | indication value based on the detected value of a motor current detection part. This achieves the intended purpose.

  According to the ceiling fan according to one aspect of the present invention, since the motor torque can be made constant, it is possible to obtain the effect that the ceiling fan can exhibit its maximum capacity without being affected by the distance between the blade and the ceiling in the installed state. .

FIG. 1 is an external view showing a ceiling fan according to the present invention. FIG. 2 is a perspective view showing a ceiling fan configuration according to the present invention. FIG. 3 is a block diagram showing the configuration of the ceiling fan according to Embodiment 1 of the present invention. FIG. 4 is a graph showing the rotational speed-torque characteristics of the brushless DC motor according to Embodiment 1 of the present invention. FIG. 5 is a block diagram showing a configuration of a ceiling fan according to Embodiment 2 of the present invention. FIG. 6 is a graph showing the rotational speed-torque characteristics of the brushless DC motor according to Embodiment 2 of the present invention. FIG. 7 is a block diagram showing a configuration of a ceiling fan according to Embodiment 3 of the present invention. FIG. 8 is a block diagram showing a configuration of a ceiling fan according to Embodiment 4 of the present invention. FIG. 9 is a graph showing the rotational speed-torque characteristics of the brushless DC motor according to Embodiment 4 of the present invention. FIG. 10 is a block diagram showing a configuration of a ceiling fan according to the fifth embodiment of the present invention. FIG. 11 is a graph showing the rotational speed-torque characteristics of the brushless DC motor according to Embodiment 5 of the present invention. FIG. 12 is a block diagram showing a configuration of a conventional ceiling fan. FIG. 13 is a graph showing the rotational speed-torque characteristics of a brushless DC motor mounted on a conventional ceiling fan.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following embodiment is an example embodying the present invention, and does not limit the technical scope of the present invention. Moreover, the same code | symbol is attached | subjected about the same site | part through all drawings, and description is abbreviate | omitted. Furthermore, in each drawing, the description of the details of each part not directly related to the present invention is omitted.

(Embodiment 1)
As shown in FIG. 1, the ceiling fan 1 according to the present embodiment is attached to a ceiling (not shown) and has a plurality of blades 3 around the main body. As shown in FIG. 2, the ceiling fan 1 has a brushless DC motor 10 mounted inside the main body, and the blades 3 are rotated by the brushless DC motor 10 to blow air downward in the drawing, that is, vertically downward.

  Below, the drive control of the ceiling fan 1 is demonstrated in detail.

  As shown in FIG. 3, the ceiling fan 1 includes a blade 3, a brushless DC motor 10, a rectifier diode 12, a smoothing capacitor 13, an inverter circuit 4, a Hall IC 9 (9u, 9v, 9w), a drive logic control unit 5, and a duty instruction. Part 6 is provided.

  The brushless DC motor 10 includes a drive coil 2 (2u, 2v, 2w). The drive of the brushless DC motor 10 is controlled by the drive logic control unit 5 by sequentially energizing the drive coil 2 via the three-phase inverter circuit 4.

  That is, the AC voltage supplied from the AC power supply 11 is rectified by the rectifier diode 12, smoothed to a DC voltage by the smoothing capacitor 13, and applied to the inverter circuit 4.

  The inverter circuit 4 includes three switching elements 7 (7u, 7v, 7w) constituting the upper stage and three switching elements 8 (8u, 8v, 8w) constituting the lower stage, and the switching elements 7, 8 are bridged. It is connected.

  The drive logic control unit 5 sequentially applies all the waves in a predetermined direction and order to the drive coils 2u, 2v, and 2w based on signals from the three Hall ICs 9u, 9v, and 9w that detect the rotational position of the brushless DC motor 10. Energize. At this time, the drive logic control unit 5 controls the supply current to the brushless DC motor 10 by PWM-controlling the DC voltage applied to the inverter circuit 4 by the upper switching element 7 or the lower switching element 8. . A series of control procedures for rotationally driving the brushless DC motor 10 by the drive logic control unit 5 is defined as drive logic.

  The duty instruction unit 6 instructs an ON / OFF duty when the drive logic control unit 5 performs PWM control of the switching elements 7 and 8.

  By the way, in the brushless DC motor 10 which concerns on this Embodiment, the motor current detection part 14 is further provided, and the duty instruction | indication part 6 controls a motor torque uniformly by performing the following control.

  In other words, the motor current detection unit 14 detects the current values of the three phases flowing through the respective drive coils 2 u, 2 v, 2 w and transmits them to the duty instruction unit 6.

  The duty instruction unit 6 changes the duty ratio based on the motor current value detected by the motor current detection unit 14 and the predetermined current value stored in the memory. Specifically, when the motor current value is lower than a predetermined current value, the duty ratio is increased. Further, when the motor current value is higher than the predetermined current value, the duty ratio is decreased. Thereby, the motor current can be maintained at a predetermined current value. Since the motor torque is proportional to the value of the current flowing through the motor, the motor torque can be controlled to be constant as a result.

  When such a ceiling fan 1 is installed on the ceiling, the ease of wind flow varies depending on the distance between the blade 3 and the ceiling, and the load applied to the blade 3 varies.

  The curve in FIG. 4 is the load characteristic of the blade 3 due to the difference in the distance between the blade and the ceiling. In FIG. 4, a thick line 41 indicates the relationship between the torque and the rotational speed when the distance between the ceiling and the blades is long. And the thin line 42 has shown the relationship between the torque and rotation speed in the state where the distance of a ceiling and a blade | wing is short.

  In the conventional ceiling fan shown in FIG. 12, as shown in FIG. 13, the number of rotations of the motor is constant at a predetermined number of revolutions, that is, the control state is controlled to coincide with the rotation number constant axis 43. Has been. For this reason, in the installation state where the wind does not flow easily, that is, in the state where the distance between the blade 103 and the ceiling is short, the rotation is performed at point a on the rotation speed constant axis 43. On the other hand, in the installation state where the wind easily flows, that is, in the state where the distance between the blade 103 and the ceiling is long, the rotation is performed at the point b on the rotation speed constant axis 43. From the viewpoint of blade strength and motor temperature rise, if the load torque at point a is the maximum rated output of the ceiling fan, the maximum output cannot be achieved at point b operated at the same rotational speed.

  On the other hand, according to the present invention, the motor current can be made constant, that is, the motor torque can be controlled to be constant. That is, the control state is controlled so as to coincide with the constant current axis 44. For this reason, in the installation state where the wind does not flow easily, that is, in the state where the distance between the blade 3 and the ceiling is short, it rotates at point a on the current constant axis 44. On the other hand, in the installation state where the wind easily flows, that is, in the state where the distance between the blade 3 and the ceiling is long, the rotation is performed at the point c on the constant current axis 44.

  According to the ceiling fan 1 according to the present embodiment, the fan can be rotated by rotating the blade with a constant torque without being affected by the change in the distance between the blade 3 and the ceiling depending on the installation state of the ceiling fan 1. it can. Then, by setting the maximum capacity based on the current value, it is possible to operate up to the upper limit of the limit due to the blade strength and the motor temperature rise, and the capacity of the ceiling fan 1 can be sufficiently extracted.

(Embodiment 2)
The second embodiment will be described with reference to FIGS.

  In the ceiling fan 1b according to the second embodiment, the current flowing through the inverter circuit 4 is detected by the power supply current detector 15 as shown in FIG.

  Based on the power supply current value from the power supply current detection unit 15, the duty instruction unit 6 increases the duty when the power supply current value is lower than the predetermined current value stored in the memory in advance, and the power supply current value is set to the predetermined current value. If higher, reduce the duty. Thereby, the duty instruction | indication part 6 controls a power supply current to predetermined current.

  According to such a configuration, the current supplied to the inverter circuit 4 can be detected at one place.

  In the brushless DC motor 10, the relationship between the torque and the number of rotations changes as shown by five thin lines 45 shown in FIG. 6 according to the ON / OFF duty output from the duty instruction unit 6.

In other words, when the duty is 100%, the straight line connecting the point where the rotational speed is 0 min ⁻¹ and the torque is 4.0 N · m and the point where the torque is 0 N · m and the rotational speed is 400 min ⁻¹ is the torque. It becomes relation of number of rotations.

If duty of 80% and a point of 3.2 N · m which is 80% of the speed torque at 0min ^-1 4.0 N · m, torque rotation speed at 0N · m for 400 min ^-1 80 A straight line connecting the points of 320 min− ¹ , which is%, represents the relationship between torque and rotational speed.

When the duty is 60%, the rotation speed is 0 min ⁻¹ and the torque is 4.0 N · m, which is 60% of 2.4 N · m, and the torque is 0 N · m and the rotation speed is 400 min ⁻¹ . A straight line connecting the points of 240 min ⁻¹ , which is a percentage, shows the relationship between torque and rotational speed.

  When the duty is 40% or 20%, the torque and the rotational speed are straight lines according to the same calculation.

The duty D, motor current Im, and power supply current Is include
Is = D × Im
The torque constant kt, the motor current Im, and the torque T are
T = kt × Im
There is a relationship.

When the torque constant kt is set to 10 N · m / A and the power supply current Is is controlled to 0.1 A, the rotation speed N is D = 100%, Im = 0.10 A, T = 1.0 N · m in the characteristics shown in FIG. , N = 300min ^-1
D = 80%, Im = 0.13A, T = 1.3 N · m, N = 195 min ⁻¹
D = 60%, Im = 0.17A, T = 1.7 N · m, N = 73 min ⁻¹
Then, when these rotational speed N and torque T are connected, a thick line 46 in FIG. 6 is obtained.

  Thus, even if the power supply current is controlled to be constant, the motor torque can be controlled to be substantially constant.

  In addition, in this control, unlike the first embodiment, the motor current detection unit 14 that detects the three-phase motor current is not required, and therefore the motor torque can be controlled almost constant with a simple configuration.

(Embodiment 3)
A third embodiment will be described with reference to FIG.

  In the ceiling fan 1c according to the third embodiment, the current flowing through the inverter circuit 4 is detected by the power supply current detector 15 as shown in FIG. Further, the rotation speed detector 19 detects the rotation speed of the brushless DC motor 10 from the period of the square wave signals HU, HV, and HW that are output signals of the Hall ICs 9u, 9v, and 9w.

  When the current Is detected by the power supply current detector 15 is smaller than, for example, a predetermined value Ip stored in advance in the memory, the duty instruction unit 6 determines the duty instruction value based on the rotational speed Ns detected by the rotational speed detector 19. That is, the duty instruction value is increased or decreased so that the rotation speed Ns detected by the rotation speed detector 19 approaches the predetermined rotation speed Ns stored in the memory in advance.

Specifically, when the rotational speed difference between the predetermined rotational speed Nt and the detected rotational speed Ns is Nd,
Nd = Nt−Ns
The duty increase / decrease value Dd proportional to the rotational speed difference Nd is Dd = α × Nd where the proportionality constant is α.
It becomes.

If the current duty instruction value is D _n and the next duty instruction value is D _{n + 1} , D _{n + 1} = D _n + Dd
It becomes.

When the detected rotational speed Ns is smaller than the predetermined rotational speed Nt, the rotational speed difference Nd is a positive value, and the duty increase / decrease value Dd proportional to the rotational speed difference Nd is also a positive value. Then, the next duty instruction value D _{n + 1} becomes larger than the current duty instruction value D _n .

  By repeating the above-described processing, the duty instruction value gradually increases, the rotational speed of the brushless DC motor 10 increases, and the predetermined rotational speed Nt matches the detected rotational speed Ns.

Conversely, when the detected rotational speed Ns is greater than the predetermined rotational speed Nt, the rotational speed difference Nd is a negative value, and the duty increase / decrease value Dd proportional to the rotational speed difference Nd is also a negative value. The next duty instruction value D _{n + 1} is smaller than the current duty instruction value D _n .

  By repeating the above-described processing, the duty instruction value gradually decreases, the rotational speed of the brushless DC motor 10 decreases, and the predetermined rotational speed Nt matches the detected rotational speed Ns.

  That is, the rotation speed of the brushless DC motor 10 can be controlled to a predetermined rotation speed Nt.

  On the other hand, when the current Is detected by the power supply current detection unit 15 is larger than the predetermined value Ip, as shown in the second embodiment, the power supply current is controlled to be constant and the motor torque is controlled to be substantially constant.

  In this way, the control is switched depending on the magnitude of the current Is detected by the power supply current detector 15 and the predetermined value Ip.

That means
When Is <Ip, the rotational speed is controlled to be constant. When Is ≧ Ip, the motor torque is controlled to be substantially constant.

  When the power supply current Is is smaller than the predetermined value Ip and the load of the brushless DC motor 10 is small in an installation state where the distance between the blade 3 and the ceiling is long and the wind easily flows, there is a margin in the motor output. For this reason, in this control, the rotation speed of the brushless DC motor 10 can be controlled to be constant and the blades 3 can be rotated to generate a constant air volume.

  Further, when the distance between the blade 3 and the ceiling is short and the wind is difficult to flow and the power source current Is is larger than the predetermined value Ip and the load of the brushless DC motor 10 is large, the motor output has no margin. For this reason, the motor torque is controlled to be substantially constant, and the motor output is controlled to be substantially constant at the maximum.

  In this way, while the basic operation is to generate a constant air volume by controlling the rotational speed to be constant, the motor output is controlled to the maximum constant when the installation state is poor and the motor load is large. Therefore, the overload state to the motor can be prevented and it can be used safely.

  In addition, it is not necessary to manufacture individual products according to the installation state, leading to a reduction in manufacturing costs.

(Embodiment 4)
The fourth embodiment will be described with reference to FIGS.

  In the ceiling fan 1d according to the fourth embodiment, the current flowing through the inverter circuit 4 is detected by the power supply current detector 15 as shown in FIG. The motor current calculation unit 16 calculates the motor current from the duty instruction value output from the duty instruction unit 6 and the power supply current detection value detected by the power supply current detection unit 15.

As described in the third embodiment, the duty D, the motor current Im, and the power supply current Is include
Is = D × Im
There is a relationship.

  Based on the motor current value from the motor current calculation unit 16, the duty instruction unit 6 performs control to increase the duty when the motor current value is lower than a predetermined current value. On the other hand, when the motor current value is higher than the predetermined current value, control is performed to reduce the duty. In this way, the duty instruction unit 6 controls the duty, thereby controlling the motor current to a predetermined current. Since the motor torque is proportional to the motor current, the motor torque can be controlled to be constant.

  In this configuration, although the motor current detection unit 14 for detecting the three-phase motor current is unnecessary, it is possible to calculate the motor current, so that the motor torque can be accurately and uniformly controlled with a simple configuration.

  However, according to the fourth embodiment, the motor torque can be controlled to be substantially constant, but when the power supply voltage changes, the constant value of the torque also changes.

That is, in the fourth embodiment, as shown in FIG. 9, the motor characteristic with a power supply voltage of 240V and a duty of 100% is a thin solid line 47, but the motor characteristic with a power supply voltage of 200V and a duty of 100% is a thin dotted line. 48. When the torque constant kt is set to 10 N · m / A and the power supply current Is is controlled to 0.1 A, the rotation speed N is D = 100%, Im = 0.10 A, T = 1 in the characteristics of the power supply voltage 240 V in FIG. 0.0 N · m, N = 300 min ⁻¹
D = 80%, Im = 0.13A, T = 1.3 N · m, N = 195 min ⁻¹
D = 60%, Im = 0.17A, T = 1.7 N · m, N = 73 min ⁻¹
It becomes.

  When these rotational speed N and torque T are connected, a thick solid line 49 in FIG. 9 is obtained.

In the characteristics of the power supply voltage 200V in FIG. 9, the rotation speed N is D = 100%, Im = 0.10 A, T = 1.0 N · m, N = 233 min ⁻¹
D = 80%, Im = 0.13A, T = 1.3 N · m, N = 142 min ⁻¹
D = 60%, Im = 0.17A, T = 1.7 N · m, N = 33 min ⁻¹
Then, when these rotational speed N and torque T are connected, a thick dotted line 50 in FIG. 9 is obtained. That is, the torque varies depending on the power supply voltage.

(Embodiment 5)
Therefore, the fifth embodiment will be described with reference to FIGS.

  In the ceiling fan 1e according to the fifth embodiment, as shown in FIG. 10, the current flowing through the inverter circuit 4 is detected by the power supply current detection unit 15, and the voltage applied to the inverter circuit 4 is detected by the power supply voltage detection unit 17. Detect with. Then, the power calculator 18 calculates the product of the power supply current value and the power supply voltage value.

  Based on the power value from the power calculation unit 18, the duty instruction unit 6 increases the duty when the power value is lower than the predetermined power value, and decreases the duty when the power value is higher than the predetermined power value. The power is controlled to a predetermined power.

As shown in FIG. 11, the state in which the power supply voltage is 240 V and the power supply current Is is controlled to 0.1 A is the thick solid line 51, and the power is controlled to 24 W. When the power supply voltage is 200 V, controlling the power to 24 W is the same as the state in which the power supply current Is is controlled to 0.12 A. When the power supply current Is is controlled to 0.12 A, the rotational speed N is D = 100%, Im = 0.12 A, T = 1.2 N · m, N = 213 min ^{−1 in} the characteristics of the power supply voltage 200 V in FIG.
D = 80%, Im = 0.15A, T = 1.5 N · m, N = 117 min ⁻¹
D = 60%, Im = 0.20A, T = 2.0 N · m, N = 0 min− ¹
Then, when these rotational speed N and torque T are connected, a thick dotted line 52 in FIG. 11 is obtained. That is, it becomes the same as the thick solid line 51 of the power supply voltage 240V, and can be controlled to the same torque even if the power supply voltage changes.

  In the present embodiment, the motor current detector 14 that detects the three-phase motor current is not necessary, and therefore the motor torque can be controlled to be almost constant with a simple configuration without being affected by the power supply voltage.

  In each embodiment, the Hall ICs 9u, 9v, and 9w are provided as a method for detecting the rotational position of the brushless DC motor 10. However, a sensorless driving method in which no position sensor is provided may be used.

(Outline of the embodiment)
A ceiling fan according to one aspect of the present invention includes a brushless DC motor, an inverter circuit, a drive logic control unit, a duty instruction unit, and a motor current detection unit. The brushless DC motor includes a drive coil. The inverter circuit includes an upper stage and a lower stage, and is bridge-connected by a plurality of switching elements. The drive logic control unit performs PWM control on the DC voltage applied to the inverter circuit and also controls drive logic for sequentially energizing the drive coil. A duty instruction | indication part instruct | indicates the ON / OFF duty in PWM control. The motor current detection unit detects a current flowing through the drive coil. And a duty instruction | indication part has a structure which determines a duty instruction | indication value based on the detected value of a motor current detection part.

  As a result, the motor current can be controlled to be constant, the motor torque proportional to the motor current is also constant, and the load torque applied to the ceiling fan is constant. Therefore, the ceiling fan has an effect that the maximum capacity can be exhibited without being affected by the distance between the blade and the ceiling depending on the installation state.

  A ceiling fan according to another aspect of the present invention includes a brushless DC motor, an inverter circuit, a drive logic control unit, a duty instruction unit, and a power supply current detection unit. The brushless DC motor includes a drive coil. The inverter circuit includes an upper stage and a lower stage, and is bridge-connected by a plurality of switching elements. The drive logic control unit performs PWM control on the DC voltage applied to the inverter circuit and also controls drive logic for sequentially energizing the drive coil. A duty instruction | indication part instruct | indicates the ON / OFF duty in PWM control. The power supply current detection unit detects a current supplied to the inverter circuit. And a duty instruction | indication part determines a duty instruction | indication value based on the detected value of a power supply current detection part.

  This eliminates the need for a motor current detection unit that detects the three-phase motor current, and thus has an effect of controlling the motor torque substantially constant with a simple configuration.

  Moreover, in the specific situation of the ceiling fan of the said structure, the rotation speed detection part which detects the rotation speed of a brushless DC motor is further provided. Then, when the detected current value by the power source current detecting unit is smaller than the predetermined value, the duty indicating unit determines the duty indicating value based on the detected rotational speed value by the rotational speed detecting unit. Further, the duty instruction unit determines the duty instruction value based on the detected current value by the power source current detector when the detected current value by the power source current detector is larger than a predetermined value.

  A ceiling fan according to another aspect of the present invention includes a brushless DC motor, an inverter circuit, a drive logic control unit, a duty instruction unit, a power supply current detection unit, a duty detection unit, and a motor current calculation. A part. The brushless DC motor includes a drive coil. The inverter circuit includes an upper stage and a lower stage, and is bridge-connected by a plurality of switching elements. The drive logic control unit performs PWM control on the DC voltage applied to the inverter circuit and also controls drive logic for sequentially energizing the drive coil. A duty instruction | indication part instruct | indicates the ON / OFF duty in PWM control. The power supply current detection unit detects a current supplied to the inverter circuit. The duty detection unit detects a duty instruction value output from the duty instruction unit. The motor current calculation unit calculates the motor current from the detection value of the power source current detection unit and the detection value of the duty detection unit. And a duty instruction | indication part determines a duty instruction | indication value based on the calculated value of a motor current calculating part.

  As a result, the motor current detection unit for detecting the three-phase motor current is unnecessary, and the motor current can be calculated. Therefore, the motor torque can be accurately and uniformly controlled with a simple configuration.

  A ceiling fan according to another aspect of the present invention includes a brushless DC motor, an inverter circuit, a drive logic control unit, a duty instruction unit, a power supply current detection unit, a power supply voltage detection unit, and power supply power. And an arithmetic unit. The brushless DC motor includes a drive coil. The inverter circuit includes an upper stage and a lower stage, and is bridge-connected by a plurality of switching elements. The drive logic control unit performs PWM control on the DC voltage applied to the inverter circuit and also controls drive logic for sequentially energizing the drive coil. A duty instruction | indication part instruct | indicates the ON / OFF duty in PWM control. The power supply current detection unit detects a current supplied to the inverter circuit. The power supply voltage detection unit detects a voltage supplied to the inverter circuit. The power supply power calculation unit calculates power supply power from the detection value of the power supply current detection unit and the detection value of the power supply voltage detection unit. And a duty instruction | indication part determines a duty instruction | indication value based on the calculated value of a power supply electric power calculating part.

  As a result, the motor current detection unit for detecting the three-phase motor current is not required, and the motor torque can be controlled almost constant without being influenced by the power supply voltage with a simple configuration.

  The ceiling fan according to the present invention is useful as a ceiling fan for driving a fan because it can blow the fan with a constant torque with the maximum performance without being affected by the change in the distance between the blade and the ceiling. It is.

1, 1b, 1c, 1d, 1e Ceiling fan 2, 2u, 2v, 2w Drive coil 3 Blade 4 Inverter circuit 5 Drive logic control unit 6 Duty instruction unit 7, 7u, 7v, 7w Upper stage switching elements 8, 8u, 8v , 8w Lower stage switching element 9, 9u, 9v, 9w Hall IC
DESCRIPTION OF SYMBOLS 10 Brushless DC motor 11 AC power supply 12 Rectifier diode 13 Smoothing capacitor 14 Motor current detection part 15 Power supply current detection part 16 Motor current calculation part 17 Power supply voltage detection part 18 Power calculation part

Claims (5)

A brushless DC motor with a drive coil;
An inverter circuit composed of an upper stage and a lower stage and bridge-connected by a plurality of switching elements,
A PWM control of the DC voltage applied to the inverter circuit, and a drive logic control unit for controlling a drive logic for sequentially energizing the drive coil,
A duty instruction unit for instructing an ON / OFF duty in the PWM control;
A motor current detector for detecting a current flowing in the drive coil;
The said duty instruction | indication part is a ceiling fan which determines a duty instruction | indication value based on the detected value of the said motor current detection part. A brushless DC motor with a drive coil;
An inverter circuit composed of an upper stage and a lower stage and bridge-connected by a plurality of switching elements,
A PWM control of the DC voltage applied to the inverter circuit, and a drive logic control unit for controlling a drive logic for sequentially energizing the drive coil,
A duty instruction unit for instructing an ON / OFF duty in the PWM control;
A power supply current detector for detecting a current supplied to the inverter circuit;
The said duty instruction | indication part is a ceiling fan which determines a duty instruction | indication value based on the detection value of the said power supply current detection part. Furthermore, a rotation speed detection unit that detects the rotation speed of the brushless DC motor is provided,
The duty instruction unit
When the detected current value by the power source current detection unit is smaller than a predetermined value, the duty instruction value is determined based on the rotation number detection value by the rotation number detection unit,
The ceiling fan according to claim 2, wherein when the detected current value by the power source current detecting unit is larger than a predetermined value, the duty instruction value is determined based on the detected current value by the power source current detecting unit. A brushless DC motor with a drive coil;
An inverter circuit composed of an upper stage and a lower stage and bridge-connected by a plurality of switching elements,
A PWM control of the DC voltage applied to the inverter circuit, and a drive logic control unit for controlling a drive logic for sequentially energizing the drive coil,
A duty instruction unit for instructing an ON / OFF duty in the PWM control;
A power supply current detector for detecting a current supplied to the inverter circuit;
A duty detection unit for detecting a duty instruction value output from the duty instruction unit;
A motor current calculation unit that calculates a motor current from the detection value of the power supply current detection unit and the detection value of the duty detection unit;
The duty instruction unit
A ceiling fan that determines the duty instruction value based on a calculation value of the motor current calculation unit. A brushless DC motor with a drive coil;
An inverter circuit composed of an upper stage and a lower stage and bridge-connected by a plurality of switching elements,
A PWM control of the DC voltage applied to the inverter circuit, and a drive logic control unit for controlling a drive logic for sequentially energizing the drive coil,
A duty instruction unit for instructing an ON / OFF duty in the PWM control;
A power supply current detector for detecting a current supplied to the inverter circuit;
A power supply voltage detector for detecting a voltage supplied to the inverter circuit;
A power supply power calculation unit for calculating power supply power from the detection value of the power supply current detection unit and the detection value of the power supply voltage detection unit;
The duty instruction unit
A ceiling fan that determines the duty instruction value based on a calculation value of the power supply power calculation unit.

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