JP7315337B2 - FAN MOTOR, ELECTRONIC DEVICE, AND MOTOR CONTROL METHOD - Google Patents

Description

The present invention relates to a fan motor, an electronic device, and a motor control method, and more particularly to a fan motor, an electronic device, and a motor control method having an advance angle control function.

2. Description of the Related Art Generally, a motor drive control device having an advance angle control function for efficiently driving a motor is used. Such motor drive control devices are widely used, for example, for driving fan motors used in electronic devices having air blowing functions such as air purifiers, humidifiers, dehumidifiers, and air conditioners. The motor drive control device drives the motor so that the rotation speed (number of rotations) of the motor matches the target rotation speed. At this time, the motor is efficiently driven by performing advance angle control in which the phase is advanced by an amount corresponding to the rotation speed of the motor and the drive voltage is applied to the coil of the motor.

Patent Document 1 below describes that in a driving device that performs position detection operation of a brushless motor based on induced voltage, switching to synchronous operation at low speed is performed in order to stably rotate the motor at low speed when the induced voltage is low.

JP-A-5-227787

SUMMARY OF THE INVENTION An object of the present invention is to provide a driving device, an electronic device, and a motor control method for driving a rotating body with low power consumption.

According to one aspect of the present invention to achieve the above object, a fan motor includes a motor that rotates an impeller, and a motor drive control device that controls the rotation speed of the motor to match a target rotation speed. The motor drive control device has a phase adjustment unit that adjusts the phase of the voltage applied to the motor. The second phase adjusting means adjusts the phase of the voltage to be behind the first phase adjusting means.

Preferably, the first phase adjusting means performs adjustment so as to increase the driving efficiency of the motor.

Preferably, the first phase adjustment means performs adjustment based on a predetermined adjustment value corresponding to the rotational speed of the motor.

Preferably, the phase adjustment unit has a switching element for switching between output of a first advance control signal for adjusting the phase of the voltage by the first phase adjustment unit and a second advance control signal for adjustment of the phase of the voltage by the second phase adjustment unit, and the motor drive control device controls the motor based on either the first advance control signal or the second advance control signal output from the phase adjustment unit.

Preferably, the first phase adjusting means adjusts the phase of the voltage to advance as the rotational speed of the motor increases, and the second phase adjusting means adjusts the phase of the voltage to advance by a predetermined amount.

Preferably, the first phase adjusting means adjusts the phase of the voltage so that it advances as the rotational speed of the motor increases, and the second phase adjusting means adjusts the phase of the voltage to be delayed by a predetermined amount from the case where the adjustment is performed by the first phase adjusting means.

According to another aspect of the present invention, an electronic device includes the fan motor according to any one of claims 1 to 6, and a host device that outputs a signal indicating a target rotational speed to the fan motor.

According to still another aspect of the present invention, a motor control method controls a motor that rotates an impeller so that the rotation speed of the motor reaches a target rotation speed, comprising a first phase adjustment step of adjusting the phase of the voltage applied to the motor when the target rotation speed is higher than the switching rotation speed, and a second phase adjustment step of adjusting the phase of the voltage when the target rotation speed is lower than the switching rotation speed, wherein the second phase adjustment step adjusts the phase of the voltage behind the first phase adjustment step. do

1 is a perspective view showing an electronic device according to one embodiment of the present invention; FIG. 1 is a block diagram showing a circuit configuration of a motor drive control device according to an embodiment; FIG. 1 is a diagram showing a circuit configuration of a motor drive control device according to this embodiment; FIG. 3 is a block diagram showing the configuration of a control circuit unit; FIG. 5 is a flowchart showing an example of the operation of the motor drive control device according to the present embodiment regarding advance angle control; FIG. 4 is a diagram for explaining the relationship between rotational speed and advance angle value in the embodiment; FIG. 10 is a diagram for explaining the relationship between the rotation speed and the advance angle value according to one modification of the present embodiment;

An electronic device using a motor drive control device according to one embodiment of the present invention will be described below. Note that the rotational speed is a concept including the number of revolutions (rpm).

[Embodiment]

FIG. 1 is a perspective view showing an electronic device according to one embodiment of the invention.

As shown in FIG. 1, electronic device 10 is, for example, an air cleaner. The electronic device 10 is provided with a suction port 11 for sucking indoor air and an exhaust port 12 for exhausting the air sucked from the suction port 11 . That is, the electronic device 10 sucks air from the suction port 11 and exhausts it from the exhaust port 12 . The suction port 11 is arranged near the ground surface of the electronic device 10 , and the exhaust port 12 is arranged above the electronic device 10 .

Inside the electronic device 10, for example, a filter 13, an impeller 14, and a fan motor 20A as a driving device for rotating a rotating body are provided.

The fan motor 20</b>A has a drive device including the motor 20 and the motor drive control device 1 . The motor 20 is driven by driving power supplied by the motor drive control device 1 . The rotor of the motor 20 rotates together with the impeller 14 as a rotating body. In the electronic device 10, the motor 20 and the motor drive control device 1 are attached to the housing of the fan motor 20A.

The impeller 14 rotates as the rotor of the motor 20 rotates, thereby sucking air from the outside of the electronic device 10 through the suction port 11 and discharging the sucked air through the exhaust port 12 .

The filter 13 is, for example, a purifying filter, a humidifying filter, a deodorizing filter, or the like. The filter 13 is arranged in the air guide path so that the air sucked from the suction port 11 passes through the filter 13 before reaching the impeller 14 . The air sucked from the suction port 11 is cleaned by passing through the filter 13 inside the electronic device 10 and then discharged from the exhaust port 12 .

The electronic device 10 includes a host device 50 (shown in FIG. 3) and an operation panel 51 (shown in FIG. 3). When the user operates the operation panel 51, the host device 50 controls the motor drive control device 1 accordingly. Thereby, the electronic device 10 operates according to the user's operation. By operating the operation panel 51, the user can set the volume of air to be cleaned in stages (low speed, medium speed, high speed, etc.). In addition, it is possible to set the air volume to be automatically changed according to conditions such as air pollution.

In the present embodiment, when an operation to select an air volume level (low speed (low rotation speed), medium speed (middle rotation speed), high speed (high rotation speed), etc.) is performed on the operation panel 51, a target rotation speed (target rotation speed) is set corresponding to the selected step. That is, the host device 50 outputs a target rotation speed signal Sc corresponding to the set air volume to the motor drive control device 1 of the fan motor 20A. The motor drive control device 1 drives the motor 20 at a rotation speed corresponding to the input target rotation speed signal Sc, as will be described later. In other words, the motor drive control device 1 controls the rotation speed of the motor 20 so that it reaches the target rotation speed. The host device 50 controls the motor drive control device 1 by outputting the target rotational speed signal Sc to the motor drive control device 1 . Note that the air volume may be configured to be variable steplessly (or in a large number of steps).

FIG. 2 is a block diagram showing the circuit configuration of the motor drive control device 1 according to this embodiment.

As shown in FIG. 2, in this embodiment, the motor 20 is, for example, a three-phase brushless motor. The motor drive control device 1 is configured to drive the motor 20 by, for example, a sine wave drive method. The motor drive control device 1 rotates the motor 20 by outputting a sine wave drive signal to the motor 20 and periodically passing a sine wave drive current (a wave obtained by synthesizing a sine wave and a wave different from a sine wave) to the coils Lu, Lv, and Lw of the motor 20. Note that the driving method of the motor 20 is not limited to this.

The motor drive control device 1 includes a motor drive section 2 having an inverter circuit 2a and a predrive circuit 2b, a control circuit section (an example of a control section) 3, and an FG signal generation section 4. FIG. Note that the components shown in FIG. 2 are part of the entire motor drive control device 1, and the motor drive control device 1 may have other components in addition to those shown in FIG.

In the present embodiment, the motor drive control device 1 is an integrated circuit device (IC) that is entirely packaged except for the FG signal generator 4 . That is, in the motor drive control device 1 , the motor drive section 2 is integrated together with the control circuit section 3 . Part of the motor drive control device 1 may be packaged as one integrated circuit device, or all or part of the motor drive control device 1 may be packaged together with other devices to form one integrated circuit device.

The inverter circuit 2a constitutes the motor driving section 2 together with the pre-drive circuit 2b. The inverter circuit 2a energizes the coils Lu, Lv, Lw of the motor 20 based on the output signals Vuu, Vul, Vvu, Vvl, Vwu, Vwl output from the predrive circuit 2b. The inverter circuit 2a is configured by, for example, a series circuit pair of two switch elements provided at both ends of the power supply Vcc, arranged for each phase (U-phase, V-phase, W-phase) of the coils Lu, Lv, and Lw. In each pair of two switch elements, a terminal of each phase of the motor 20 is connected to a connection point between the switch elements.

The pre-drive circuit 2b generates six types of output signals corresponding to the switch elements of the inverter circuit 2a for driving the inverter circuit 2a based on the control by the control circuit unit 3, and outputs the output signals to the inverter circuit 2a. The predrive circuit 2b generates output signals Vuu, Vul, Vvu, Vvl, Vwu, and Vwl based on the drive control signal Sd output from the control circuit section 3. FIG. In the inverter circuit 2a, switching elements corresponding to the respective output signals Vuu, Vul, Vvu, Vvl, Vwu, and Vwl perform ON/OFF operations. As a result, drive voltages are applied to the coils Lu, Lv, and Lw of the motor 20 .

FIG. 3 is a diagram showing the circuit configuration of the motor drive control device 1 according to this embodiment.

As shown in FIG. 3 , the FG signal generator 4 generates a real rotational speed signal Sr and outputs it to the control circuit 3 . The actual rotation speed signal Sr is a signal corresponding to the actual rotation speed of the motor 20 (rotation speed of the rotor; hereinafter sometimes referred to as the actual rotation speed). In this embodiment, the actual rotation speed signal Sr is the FG signal. That is, the FG signal generator 4 has, for example, an FG pattern 4a, which is a coil pattern formed on a substrate arranged near the rotor of the motor 20 . The FG signal generator 4 generates and outputs an actual rotation speed signal Sr according to the induced voltage of the FG pattern 4a. Note that the actual rotation speed signal Sr is not limited to the signal generated in this way. For example, the actual rotation speed signal Sr may be an FG signal generated based on the output of a Hall element or Hall IC, or a signal having characteristics such as a frequency corresponding to the rotation speed of the motor 20 generated using an encoder or the like.

In this embodiment, the control circuit unit 3 controls the operation of the motor 20 by outputting a drive control signal Sd for driving the motor 20 to the motor drive unit 2 to control the motor drive unit 2 .

An actual rotational speed signal Sr and a target rotational speed signal Sc are input to the control circuit unit 3 .

The target rotation speed signal Sc is, for example, a clock signal output from a clock terminal of the host device 50 . The target rotation speed signal Sc is a signal with a frequency corresponding to the target rotation speed of the motor 20 . In other words, the target rotation speed signal Sc is information indicating a target value (target rotation speed) of the rotation speed of the motor 20 for instructing at what Hz (rpm) the motor 20 should be rotated.

The control circuit section 3 generates a drive control signal Sd based on the actual rotational speed signal Sr and the target rotational speed signal Sc, and outputs the drive control signal Sd to the pre-drive circuit 2b of the motor drive section 2. FIG. The control circuit unit 3 controls the rotation of the motor 20 by outputting a drive control signal Sd to the motor drive unit 2 so that the motor 20 rotates at the target rotation speed according to the target rotation speed indicated by the target rotation speed signal Sc and the rotation speed of the motor 20 indicated by the actual rotation speed signal Sr. The motor drive unit 2 outputs a sine wave drive signal to the motor 20 based on the drive control signal Sd to drive the motor 20 .

The control circuit unit 3 outputs the drive control signal Sd so that the actual rotation speed of the motor 20 follows the target rotation speed corresponding to the target rotation speed signal Sc. That is, when the target rotation speed is constant, even if the load on the motor 20 fluctuates due to changes in the environment around the electronic device 10, etc., the drive control signal Sd is output so that the actual rotation speed becomes the target rotation speed, and the magnitude of the drive voltage applied to the motor 20 is adjusted. When the target rotation speed is changed (for example, when an operation to change from "low speed" to "medium speed" or the like is performed on the operation panel 51) or when the motor 20 returns from a locked state after being temporarily locked, the target rotation speed and the actual rotation speed deviate relatively greatly. do.

In this embodiment, the control circuit section 3 includes a speed control circuit 31 and a sine wave drive circuit 32 .

A target rotation speed signal Sc and an actual rotation speed signal Sr are input to the speed control circuit 31 . The speed control circuit 31 generates a torque command signal S1 so that the motor 20 follows the target rotation speed according to the comparison result between the target rotation speed signal Sc and the actual rotation speed signal Sr. The torque command signal S1 is a signal corresponding to the magnitude of the torque of the motor 20. FIG. If there is a deviation between the target rotation speed and the actual rotation speed, the torque command signal S1 is adjusted. That is, the rotation speed of the motor 20 is adjusted by feedback control.

A torque command signal S1 is input to the sine wave drive circuit 32 . The sine wave drive circuit 32 generates a drive control signal Sd based on the torque command signal S1 and outputs it to the motor drive section 2 . As a result, a drive voltage is applied from the motor drive unit 2 to the coils Lu, Lv, and Lw of each phase of the motor 20 at timings corresponding to the rotation of the motor 20 so that the motor 20 rotates at a torque corresponding to the torque command signal S1.

FIG. 4 is a block diagram showing the configuration of the control circuit section 3. As shown in FIG.

The configuration and operation of the control circuit section 3 will be described in more detail below.

In this embodiment, the control circuit unit 3 adjusts the phase of the drive voltage applied to the motor 20 . That is, the control circuit unit 3 controls the advance angle of the drive voltage applied to the motor 20 . The advance angle control is performed by a phase adjustment section 33 which is composed of part of the speed control circuit 31 and part of the sine wave drive circuit 32 of the control circuit section 3 .

The speed control circuit 31 has an advance angle determination circuit 34 and a switching rotation speed detection circuit 35 . The advance angle determination circuit 34 and the switching rotation speed detection circuit 35 are included in the phase adjustment section 33 .

The sine wave drive circuit 32 has a sine wave generation circuit 32b, a first lead angle control section (an example of a first phase adjustment means) 36, a second lead angle control section (an example of a second phase adjustment means) 37, and a selector (an example of a switching element) 38. First advance control section 36 , second advance control section 37 , and selector 38 are included in phase adjustment section 33 .

The sine wave generation circuit 32b generates and outputs a drive control signal Sd corresponding to each phase of the motor 20 based on the torque command signal S1. The sine wave generation circuit 32b generates the drive control signal Sd so that the drive voltages are applied to the coils Lu, Lv, and Lw of the motor 20 in phases according to the processing result of the phase adjuster 33. FIG. That is, the motor drive control device 1 controls the motor 20 based on the signal output from the phase adjustment section 33 .

As described above, the phase adjustment section 33 includes the advance angle determination circuit 34 and the switching rotation speed detection circuit 35 of the speed control circuit 31, the first advance angle control section 36, the second advance angle control section 37, and the selector 38 of the sine wave drive circuit 32.

In the present embodiment, the phase adjustment unit 33 switches the method of adjusting the phase of the driving voltage of the motor 20 according to the target rotation speed. That is, when the target rotation speed is higher than the predetermined switching rotation speed (when the motor 20 is rotated in a high-speed range, which is a speed range higher than the switching rotation speed), the phase adjustment unit 33 adjusts the phase of the drive voltage of the motor 20 using the first adjustment method that emphasizes increasing the driving efficiency of the motor 20, and when the target rotation speed is smaller than the switching rotation speed (when the motor 20 is rotated in a low-speed range, which is a speed range lower than the switching rotation speed), the rotation speed of the motor 20 is adjusted to the target rotation speed. The phase of the drive voltage of the motor 20 is adjusted by the second adjustment method of delaying the phase of the drive voltage (decreasing the advance angle) within a range in which the rotational speed can be maintained.

The switching rotation speed is, for example, a preset rotation speed threshold.

When performing adjustment by the first adjustment method, the phase adjustment unit 33 performs advance angle control so that the phases of the induced voltages in the coils Lu, Lv, and Lw of the motor 20 and the winding current (coil current) match. In other words, the phase adjustment unit 33 performs advance control with emphasis on efficiency so that the motor 20 can be efficiently driven with low power consumption. On the other hand, the phase adjustment unit 33 performs control to delay the phase of the drive voltage when performing adjustment by the second adjustment method. In other words, the phase adjustment unit 33 performs low-advance control in which the induced voltages of the coils Lu, Lv, and Lw of the motor 20 become relatively large, so that the current flowing through the coils Lu, Lv, and Lw becomes relatively small. After changing the target rotation speed, the control circuit unit 3 outputs a signal corresponding to the changed target rotation speed, and the phase adjustment unit 33 delays the phase of the drive voltage according to the changed target rotation speed.

Adjustment according to the first adjustment method is performed using the first advance angle control section 36 . Further, adjustment by the second adjustment method is performed using the second advance angle control section 37 . That is, the first advance control unit 36 adjusts the phase of the voltage when the target rotational speed is higher than the switching rotational speed. Further, the second advance control section 37 adjusts the phase of the voltage when the target rotational speed is lower than the switching rotational speed. The second advance control section 37 makes adjustments so that the phase of the voltage lags behind that of the first advance control section 36 .

In the phase adjustment section 33 , the lead angle determination circuit 34 receives the actual rotational speed signal Sr. The lead-angle determination circuit 34 determines a preset lead-angle value (an adjustment value for advancing the phase of applying the drive voltage from the phase of the FG signal) according to the rotational speed of the motor 20 . The lead-angle determination circuit 34 can determine the lead-angle value by selecting, for example, the lead-angle value corresponding to the actual rotation speed from a preset combination of the rotation speed and the lead-angle value corresponding thereto. That is, the lead-angle setting circuit 34 determines a predetermined lead-angle value corresponding to the rotation speed of the motor 20 . The lead-angle determination circuit 34 may calculate the lead-angle value corresponding to the actual rotational speed according to a preset calculation rule. The lead-angle determination circuit 34 outputs information about the determined lead-angle value as a lead-angle value signal S2.

A target rotation speed signal Sc is input to the switching rotation speed detection circuit 35 . Based on the target rotation speed signal Sc, the switching rotation speed detection circuit 35 outputs a selection signal S3 corresponding to the comparison result between the target rotation speed and the switching rotation speed. For example, in the present embodiment, the switching rotation speed detection circuit 35 detects that the target rotation speed is lower than the switching rotation speed, and outputs the selection signal S3 according to the detection result. The selection signal S3 is a signal that becomes a predetermined voltage when it is detected that the target rotation speed is lower than the switching rotation speed, but it is not limited to this. Further, when the switching rotation speed detection circuit 35 detects that the target rotation speed is higher than the switching rotation speed or that the target rotation speed is above or below the switching rotation speed, the switching rotation speed detection circuit 35 may output the selection signal S3 accordingly.

A lead-angle value signal S<b>2 is input to the first lead-angle control unit 36 . Based on the lead-angle value signal S2, the first lead-angle control unit 36 outputs a first lead-angle control signal S4 for controlling the sine wave generation circuit 32b to advance the phase by the lead-angle value determined by the lead-angle determination circuit 34. That is, the first advance control unit 36 outputs a first advance control signal S4 for performing advance control with emphasis on efficiency, and performs advance control so that the induced voltage of the coil of the motor 20 becomes small. In other words, the first advance control section 36 outputs the first advance control signal S4 and adjusts the phase of the driving voltage of the motor 20 so that the driving efficiency of the motor 20 is increased.

The second advance control section 37 makes adjustments so that the phase of the voltage lags behind that in the case where the first advance control section 36 performs advance control. The second lead-angle control unit 37 outputs a second lead-angle control signal S5 for controlling the sine wave generation circuit 32b so that the phase lags behind the efficiency-oriented lead-angle control. That is, the second advance angle control section 37 outputs the second advance control signal S5 for performing advance control for a low advance angle.

In the present embodiment, the second advance control section 37 outputs the second advance control signal S5 based on information stored in advance in the memory 37b. For example, the second lead-angle control unit 37 outputs the second lead-angle control signal S5 so that the lead-angle control is performed by applying the lead-angle value stored in advance in the memory 37b. That is, the second advance angle control section 37 sets the phase of the driving voltage based on the predetermined setting value stored in the memory 37b. When delaying the phase of the drive voltage, the second advance control section 37 sets the phase of the drive voltage to a predetermined set value to delay the phase of the drive voltage. In other words, the second advance control section 37 adjusts the phase of the voltage to advance by a predetermined amount.

Here, the predetermined setting value stored in the memory 37b may be a lead-angle value smaller than the lead-angle value determined by the lead-angle determination circuit 34 when the motor 20 is rotating at the switching rotation speed, and may be set to a lead-angle value that can maintain the rotation speed of the motor 20 at the target rotation speed even when the lead-angle value is applied.

The selector 38 receives the first lead-angle control signal S4, the second lead-angle control signal S5, and the selection signal S3. The selector 38 outputs either the first lead-angle control signal S4 or the second lead-angle control signal S5 to the sine wave generation circuit 32b according to the selection signal S3. In other words, the selector 38 switches between outputting the first lead-angle control signal S4 for adjusting the phase of the voltage by the first lead-angle controller 36 and the second lead-angle control signal S5 for adjusting the phase of the voltage by the second lead-angle controller 37. The selector 38 selects whether to use the first advance control section 36 or the second advance control section 37 to adjust the phase of the driving voltage of the motor 20 . That is, the phase adjustment unit 33 switches between the first adjustment method and the second adjustment method depending on the target rotation speed.

In the present embodiment, the selector 38 causes advance control by the second advance control section 37 when the target rotational speed is lower than the switching rotational speed, and otherwise causes advance control by the first advance control section 36 when the target rotational speed is greater than the switching rotational speed. In other words, based on the target rotational speed, the selector 38 causes the first advance control section 36 to perform advance control in the high speed range, and the second advance control section 37 to perform advance control in the low speed range. Such operation of the selector 38 is performed according to the selection signal S3 output from the switching rotation speed detection circuit 35. FIG.

FIG. 5 is a flow chart showing an example of the operation of the motor drive control device 1 according to the present embodiment regarding advance angle control.

Since it is configured as described above, the motor drive control device 1 performs operations related to advance angle control as shown in FIG.

That is, in step S11, the speed control circuit 31 determines whether or not the target rotational speed signal Sc has been detected. In other words, when the driving of the motor 20 is stopped, the speed control circuit 31 determines whether or not a start command for starting the motor 20 has been detected. If the target rotation speed signal Sc has not been detected, it waits until it is detected. When the target rotational speed signal Sc is detected, the process proceeds to step S12.

In step S12, the switching rotation speed detection circuit 35 compares the target rotation speed with a predetermined switching rotation speed based on the target rotation speed signal Sc, and determines whether or not the target rotation speed is lower than the switching rotation speed. The switching rotation speed detection circuit 35 outputs a selection signal S3 according to the determination result. That is, when the target rotation speed is lower than the switching rotation speed, the process proceeds to step S14, otherwise, the process proceeds to step S13.

In step S13, the phase adjustment unit 33 performs control so that driving is performed with advance angle control emphasizing efficiency. That is, in response to the selection signal S3 output from the switching rotation speed detection circuit 35, the selector 38 outputs the first lead angle control signal S4 output from the first lead angle control section 36 to the sine wave generation circuit 32b. As a result, advance control is performed with emphasis on efficiency, and the motor 20 is driven to rotate at the target rotational speed.

On the other hand, in step S14, the phase adjustment unit 33 performs control so that driving is performed with advance angle control for reducing the winding current. That is, in response to the selection signal S3 output from the switching rotational speed detection circuit 35, the selector 38 outputs the second lead angle control signal S5 output from the second lead angle control section 37 to the sine wave generation circuit 32b. As a result, advance control is performed with a low advance angle, and the motor 20 is driven to rotate at the target rotational speed.

When the process of step S13 or step S14 ends, in step S15, the speed control circuit 31 determines whether or not it has detected that the input of the target rotational speed signal Sc has been stopped. When it is detected that the input of the target rotational speed signal Sc has been stopped, the process proceeds to step S16. Otherwise, return to step S12.

In step S16, the sine wave drive circuit 32 starts a free-run stop operation. That is, the electric power supplied to each phase of the motor 20 is turned off, and the motor 20 is stopped. When the operation of step S16 ends, a series of operations ends.

FIG. 6 is a diagram for explaining the relationship between the rotational speed and the advance value in this embodiment.

In FIG. 6, the method of adjusting the phase of the drive voltage (control mode) is shown in the upper part, and the relationship between the rotation speed of the motor 20 and the set advance value is schematically shown in the lower part.

As shown in FIG. 6, in the present embodiment, in the low-speed region where the rotation speed of the motor 20 is lower than the switching rotation speed, the phase of the drive voltage is adjusted by the second lead-angle control section 37, that is, the low-advance-angle lead-angle control. On the other hand, in a high-speed region where the rotational speed of the motor 20 is higher than the switching speed, the advance angle control that emphasizes efficiency, that is, the phase of the driving voltage is adjusted by the first advance angle control section 36 .

In the present embodiment, the first advance angle control unit 36 performs adjustment so that the phase of the voltage advances (the advance value increases) as the rotation speed of the motor 20 increases. On the other hand, the second advance angle control unit 37 adjusts so that the phase of the voltage advances by a predetermined amount (so that the advance angle value becomes a predetermined value). That is, in the low speed range, the constant advance value b1 is set regardless of the rotation speed of the motor 20 . Here, the lead-angle value b1 is set to a value smaller than the minimum value of the lead-angle value (indicated by the dashed-dotted line in FIG. 6) when the phase of the drive voltage is adjusted by the first lead-angle control section 36 even in the low-speed range, or set to zero.

In the present embodiment, in this way, in the high speed range, efficiency-oriented advance angle control, that is, the phase of the drive voltage is adjusted by the first advance angle control section 36, so the motor 20 is driven with high efficiency. On the other hand, in the low speed range, the second advance angle control section 37 performs advance control for a low advance angle, that is, adjustment such that the phase of the voltage lags behind that of the first advance angle control section 36 . In the low-speed range, the induced voltage in the coils Lu, Lv, and Lw of the motor 20 becomes relatively larger than in the case of performing the advance control with emphasis on efficiency, so that the current flowing through the coils Lu, Lv, and Lw is relatively small. At this time, the torque of the motor 20 is relatively small, but since the rotation speed is low and the load is low, the motor 20 can be rotated at the target rotation speed. Therefore, the power consumption of the motor 20 can be reduced while rotating the motor 20 at the target rotation speed. The electronic device 10 with high energy-saving performance can be manufactured using a simple hardware configuration with low manufacturing cost without using a complicated control method such as vector control.

A specific example will be described with reference to FIG. For example, in a situation where the rotational speed of the motor 20 is 600 rpm, the advance angle is set to b2 (e.g., 10 degrees) when using the efficiency-emphasizing advance control, and is set to b1 (e.g., 5 degrees) when using the low advance angle control. In such a case, when the motor current is about 100 milliamperes when the advance angle is b2, and when the motor current is about 95 milliamperes when the advance angle is b1, 5% energy saving can be achieved by performing the advance control with a low advance angle. In other words, in such a case, the switching rotation speed should be set so that when the rotation speed of the motor 20 is 600 rpm, the advance angle control is performed with a low advance angle. Further, at this time, if the advance angle control is performed with a low advance angle, the motor current becomes smaller, so that the excitation force becomes smaller. Therefore, the vibration generated in the electronic device 10 is reduced.

The switching rotation speed and the predetermined set value set by the second advance control unit 37 may be appropriately set according to the application of the fan motor 20A and the characteristics of the electronic device 10, that is, according to the rotation speed at which the fan motor 20A is used and the load that may be applied to the fan motor 20A, so that the rotation speed of the motor 20 can be maintained at the target rotation speed. The power consumption of the motor 20 can be minimized by setting the predetermined set value set by the second advance control section 37 to a value as small as possible within a range in which the rotation speed of the motor 20 can be maintained at the target rotation speed in the low speed range.

The manner in which the voltage phase is adjusted by the first advance angle control section 36 and the manner in which the voltage phase is adjusted by the second advance angle control section 37 are not limited to those of the above embodiments.

FIG. 7 is a diagram for explaining the relationship between the rotational speed and the lead-angle value according to one modification of the present embodiment.

7 schematically shows the relationship between the rotation speed of the motor 20 and the set lead-angle value, as in the lower diagram of FIG.

As shown in FIG. 7, in this modified example, the adjustment mode of the first advance angle control section 36 is the same as in the above-described embodiment. On the other hand, the second advance control section 37 performs adjustment so that the phase of the voltage is delayed by a predetermined amount from the case where the adjustment by the first advance control section 36 is performed. That is, in the low speed range, the advance angle value is set to be smaller by a predetermined amount d than when adjustment is performed by the first advance angle control section 36 (indicated by the one-dot chain line in FIG. 7). That is, in this modified example, the second advance control section 37 performs adjustment so that the phase of the voltage is delayed as the rotational speed of the motor 20 is lower. Here, the predetermined amount d is set so that the advance value is within a range in which the rotation speed of the motor 20 can be maintained at the target rotation speed over the entire low speed range.

This modification also has advantages similar to those of the embodiment described above. That is, the current flowing through the coils Lu, Lv, and Lw of the motor 20 can be kept small in the low speed range, and the power consumption of the fan motor 20A can be reduced.

[others]

The motor drive control device and the electronic equipment using it are not limited to the circuit configurations shown in the above-described embodiments and modifications thereof. A variety of circuit configurations are applicable that are configured to meet the objectives of the present invention. A motor may be configured by partially combining the features of the above embodiments and modifications. In the embodiments and modifications described above, some components may be omitted or some components may be configured in other manners.

Electronic devices are not limited to air cleaners. The electronic device may be of various types having a configuration such that the impeller is rotated by a motor. For example, the electronic device may be a fan, an air conditioner, or the like, or may be a device having a fan for cooling or ventilation.

The driving method of the motor is not limited to normal sine wave driving, but may be a rectangular wave driving method, a trapezoidal wave driving method, or a driving method in which a sine wave is specially modulated.

The switching rotation speed may not be a rotation speed that is a predetermined fixed value. For example, it may be a value specified according to a predetermined rule according to the surrounding environment (for example, temperature, humidity, etc.).

As the target rotation speed signal, a pulse width modulation signal having a duty ratio corresponding to the set air volume may be output from the host device, and the motor drive control device may drive the motor accordingly. Further, the motor drive control device may be configured to drive the motor at a preset target rotation speed to which a target rotation speed signal is not input from an external host device or the like.

In order to detect the position of the rotor, a Hall element may be used, or a Hall IC may be used as a rotor position detector of the motor.

The above-described flowcharts and the like show examples for explaining the operation, and are not limited to these. The steps shown in each figure of the flowchart are specific examples, and the flow is not limited to this flow. For example, other processing may be inserted between each step, or the processing may be parallelized.

The motor driven by the motor drive control apparatus of the present embodiment is not limited to a three-phase brushless motor, and may be a brushless motor with other number of phases. Also, the type of motor is not particularly limited.

Some or all of the processing in the above-described embodiments may be performed by software or may be performed using hardware circuits. At least a part of each component of the motor drive control device may be processed by software instead of by hardware.

A motor drive controller may be provided within the motor as a component of the motor. In this case, the motor would be equipped with a motor controller.

The above-described embodiments should be considered as illustrative in all respects and not restrictive. The scope of the present invention is indicated by the scope of the claims rather than the above description, and is intended to include all modifications within the scope and meaning equivalent to the scope of the claims.

REFERENCE SIGNS LIST 1 motor drive control device 2 motor drive section 3 control circuit section 10 electronic device 14 impeller 20 motor 20A fan motor 31 speed control circuit 32 sine wave drive circuit 33 phase adjustment section 36 first advance angle control section (an example of first phase adjustment means)
37 second advance control section (an example of second phase adjustment means)
37b memory 38 selector (an example of a switching element)
50 host device Lu, Lv, Lw coil Sc target rotation speed signal Sd drive control signal Sr actual rotation speed signal S4 first advance control signal S5 second advance control signal

Claims (7)

a motor that rotates the impeller;
a motor drive control device that controls the rotation speed of the motor so that it reaches a target rotation speed;
The motor drive control device has a phase adjustment unit that adjusts the phase of the voltage applied to the motor,
The phase adjustment unit is
first phase adjustment means for adjusting the phase of the voltage when the target rotation speed is higher than the switching rotation speed;
a second phase adjustment means for adjusting the phase of the voltage when the target rotation speed is lower than the switching rotation speed;
The first phase adjusting means advances the phase of the voltage as the rotation speed of the motor increases, thereby performing advance angle control so that the phases of the induced voltage and the current of the coil of the motor match, thereby increasing the driving efficiency of the motor.
The second phase adjusting means performs the adjustment so that the phase of the voltage lags behind the phase of the voltage adjusted by advance control performed so that the phases of the induced voltage and the current of the coil of the motor match within a range in which the rotation speed of the motor can be maintained at the target rotation speed. 2. The fan motor according to claim 1, wherein said first phase adjustment means performs said adjustment based on a predetermined adjustment value corresponding to the rotation speed of said motor. The phase adjustment unit has a switching element for switching between outputting a first advance control signal for adjusting the phase of the voltage by the first phase adjustment means and a second advance control signal for adjusting the phase of the voltage by the second phase adjustment means,
3. The fan motor according to claim 1, wherein the motor drive control device controls the motor based on one of the first advance control signal and the second advance control signal output from the phase adjustment unit. The first phase adjustment means performs the adjustment so that the phase of the voltage advances as the rotation speed of the motor increases,
4. The fan motor according to any one of claims 1 to 3, wherein said second phase adjusting means performs said adjustment so that the phase of said voltage advances by a predetermined amount. The first phase adjustment means performs the adjustment so that the phase of the voltage advances as the rotation speed of the motor increases,
4. The fan motor according to any one of claims 1 to 3, wherein said second phase adjustment means performs said adjustment such that the phase of said voltage is delayed by a predetermined amount from when said first phase adjustment means performs adjustment. a fan motor according to any one of claims 1 to 5;
and a host device that outputs a signal indicating the target rotational speed to the fan motor. A motor control method for controlling a motor that rotates an impeller so that the rotation speed of the motor reaches a target rotation speed,
a first phase adjustment step of adjusting the phase of the voltage applied to the motor when the target rotation speed is higher than the switching rotation speed;
a second phase adjustment step of adjusting the phase of the voltage when the target rotation speed is lower than the switching rotation speed;
In the first phase adjustment step, the phase of the voltage is advanced as the rotation speed of the motor increases, thereby performing advance angle control so that the phases of the induced voltage and the current of the coil of the motor match, thereby performing the adjustment so that the driving efficiency of the motor is increased,
The second phase adjustment step is a motor control method in which the phase of the voltage lags behind the phase of the voltage adjusted by advance angle control performed so that the phases of the induced voltage and the current of the coil of the motor match within a range in which the rotation speed of the motor can be maintained at the target rotation speed.

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