JP2020145772A - Motor drive control device, fan, and motor drive control method - Google Patents

Abstract

To realize a fan improved in silence while ensuring necessary air amount.SOLUTION: A motor drive control device (1) includes a control circuit portion (4) that produces a drive control signal (Sd) for controlling the rotation speed of a motor, on the basis of a speed instruction signal (Sc) instructing a target rotation speed (Rtg) of the motor (20), and a motor drive portion (2) that drives the motor on the basis of the drive control signal. The control circuit portion carries out speed feedback control that generates the drive control signal so as to make the rotation speed of the motor match the target rotation speed when the target rotation speed is lower than a threshold value (Rth), and carries out the maximum air amount control for producing the drive control signal bringing a current (Ir) flowing in the motor close to a target current value (Itg) calculated corresponding to the rotation speed of the motor, when the target rotation speed is higher than the threshold value.SELECTED DRAWING: Figure 4

Description

The present invention relates to a motor drive control device, a fan, and a motor drive control method, for example, a motor drive control device that controls an air volume of a fan rotated by a motor.

Conventionally, a fan (fan motor) is widely known as a device for cooling a component or the like provided inside a home electric appliance or an OA device.

In general, fan performance is represented by air volume-static pressure characteristics (hereinafter, also referred to as "PQ curve"). The PQ curve represents the relationship between the loss (static pressure) due to the pressure between the suction port and the discharge port of the fan and the air volume. In the PQ curve, when the static pressure is the maximum (the ventilation resistance is the maximum), the fan air volume becomes zero, and when the static pressure is zero (the ventilation resistance is zero), the fan air volume becomes the maximum (for example). See Patent Document 1).
The state where the static pressure is zero, that is, the air volume of the fan is maximum is also referred to as a "free air state".

JP-A-2009-174414

Generally, the fan is designed to obtain the required air volume in a predetermined operating range (for example, in the region where the static pressure is in the middle range). That is, the fan is designed to realize a PQ curve that provides a predetermined air volume in the required operating range. On the other hand, in a region other than the required operating range, for example, in a region where the static pressure is equal to or less than a predetermined value, the fan is more important than the air volume in quietness.

In the conventional fan, the rotation speed of the motor is controlled so as to be the rotation speed instructed by the host device, and the air volume changes depending on the pressure loss (static pressure). Therefore, the conventional fan has a problem that an air volume larger than the air volume in the required operating range is generated in a region where the static pressure is low such as in a free air state, and the noise becomes loud.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to improve quietness while ensuring a necessary air volume in a fan.

The motor drive control device according to a typical embodiment of the present invention is a control circuit that generates a drive control signal for controlling the rotation speed of the motor based on a speed command signal indicating a target rotation speed of the motor. The control circuit unit includes a unit and a motor drive unit that drives the motor based on the drive control signal. When the target rotation speed is lower than the threshold value, the rotation speed of the motor is the target rotation speed. The speed feedback control for generating the drive control signal is performed so as to match the above, and when the target rotation speed is higher than the threshold value, the current flowing through the motor is calculated in accordance with the rotation speed of the motor. It is characterized in that the maximum air volume control for generating the drive control signal so as to approach the current value is performed.

According to the motor drive control device according to the present invention, it is possible to realize a fan with improved quietness while securing a required air volume.

It is a block diagram which shows the structure of the fan which concerns on embodiment of this invention. It is a figure for demonstrating the air volume control of a fan by the motor drive control device which concerns on this embodiment. It is a figure which shows the correspondence relationship of the rotation speed of a motor, and a motor current in the maximum air volume control line of FIG. It is a block diagram which shows the structure of the motor drive control device which concerns on this embodiment. It is a figure which shows an example of the adjustment method of the rotation speed of a motor at the time of the maximum air volume control. It is a figure which shows an example of the adjustment method of the operating point of a motor at the time of the maximum air volume control. It is a flow chart which shows the flow of the air volume control of a fan by the motor drive control device which concerns on this embodiment. It is a figure which shows the relationship between the rotation speed of the motor in the fan which concerns on this embodiment, and the target rotation speed.

1. 1. Outline of Embodiment First, an outline of a typical embodiment of the invention disclosed in the present application will be described. In the following description, as an example, reference numerals on drawings corresponding to the components of the invention are described in parentheses.

[1] The motor drive control device (1) according to a typical embodiment of the present invention is based on a speed command signal (Sc) indicating a target rotation speed (Rtg) of the motor (20). The control circuit unit (4) for generating a drive control signal (Sd) for controlling the rotation speed and a motor drive unit (2) for driving the motor based on the drive control signal are provided. When the target rotation speed is lower than the threshold value (Rth), the unit performs speed feedback control to generate the drive control signal so that the rotation speed of the motor matches the target rotation speed, and the target rotation speed becomes the target rotation speed. When the value is higher than the threshold value, the maximum air volume control for generating the drive control signal so that the current (Ir) flowing through the motor approaches the target current value (Itg) calculated corresponding to the rotation speed of the motor is performed. It is characterized by doing.

[2] In the motor drive control device, the control circuit unit calculates the actual rotation speed of the motor based on a position detection signal (Sh) indicating the rotation position of the motor, and the motor is stored in advance. The target current may be calculated based on the correspondence relationship information (471) indicating the correspondence relationship between the rotation speed and the target current value and the calculated actual rotation speed.

[3] In the motor drive control device, the motor rotates the impeller (21) in the fan (100), and the corresponding relationship is that the motor in a region where the static pressure of the fan is lower than a predetermined value (Pb). The relationship between the rotation speed of the motor and the target current value may be shown.

[4] In the motor drive control device, the control circuit unit determines the rotation speed (Rr) of the motor when the current (Ir) flowing through the motor is higher than the target current value (Itg) in the maximum air volume control. ) Is generated so that the drive control signal is increased, and when the current (Ir) flowing through the motor is lower than the target current value (Itg), the drive is driven so that the rotation speed (Rr) of the motor decreases. A control signal may be generated.

[5] In the motor drive control device, in the control circuit unit, when the current (Ir) flowing through the motor is higher than the predetermined range (M) based on the target current value (Itg) in the maximum air volume control. In addition, when the rotation speed of the motor is increased and the current (Ir) flowing through the motor is within the predetermined range (M), the rotation speed of the motor is not changed and the current flowing through the motor is the predetermined value. When it is lower than the range (M), the drive control signal may be generated so as to reduce the rotation speed of the motor.

[6] In the motor drive control device, the control circuit unit includes a rotation speed calculation unit (42) that calculates the actual rotation speed (Rr) based on the position detection signal (Sh), and the rotation speed calculation unit. A speed control unit (43) that generates a first control signal (Sp1) so that the actual rotation speed (Rr) calculated by the above matches the target rotation speed (Rtg) indicated by the speed command signal (Sc). ), The target current value calculation unit (47) that calculates the target current value (Itg) based on the actual rotation speed (Rr) calculated by the rotation speed calculation unit, and the current of the current flowing through the motor. When the current value acquisition unit (46) for acquiring the value and the target rotation speed (Rtg) are higher than the threshold value (Rth), the current (Ir) flowing through the motor approaches the target current value (Itg). A drive control signal generation that generates the drive control signal (Sd) based on the maximum air volume control unit (44) that generates the second control signal (Sp2), the first control signal, and the second control signal. It may have a part (45) and.

[7] The fan (100) according to a typical embodiment of the present invention includes a motor (20), an impeller (21) rotatably configured by the rotational force of the motor (20), and a drive of the motor. The motor drive control device includes a motor drive control device (1) for controlling the motor, and the motor drive control device controls the rotation speed of the motor based on a speed command signal (Sc) indicating a target rotation speed (Rtg) of the motor. It has a control circuit unit (4) that generates a drive control signal (Sd) for driving the motor, and a motor drive unit (2) that drives the motor based on the drive control signal. When the target rotation speed (Rtg) is lower than the threshold value (Rth), speed feedback control is performed to generate the drive control signal so that the rotation speed (Rr) of the motor matches the target rotation speed (Rtg). When the target rotation speed (Rtg) is higher than the threshold value (Rth), the current (Ir) flowing through the motor approaches the target current value (Itg) calculated corresponding to the rotation speed of the motor. It is characterized in that the maximum air volume control for generating the drive control signal (Sd) is performed.

[8] The motor drive control method according to a typical embodiment of the present invention controls the drive of the motor (20) based on a speed command signal (Sc) indicating a target rotation speed (Rtg) of the motor (20). A method of generating a drive control signal (Sd) for driving the motor based on the drive control signal, and when the target rotation speed (Rtg) is lower than the threshold value (Rth), the motor The first step (S3) of generating the drive control signal so that the rotation speed (Rr) matches the target rotation speed (Rtg), and when the target rotation speed (Rtg) is higher than the threshold value (Rth). The second step (S4 to S14) of generating the drive control signal so that the current (Ir) flowing through the motor approaches the target current value (Itg) calculated corresponding to the rotation speed of the motor. It is characterized by including.

2. 2. Specific Examples of Embodiments Hereinafter, specific examples of embodiments of the present invention will be described with reference to the drawings. In the following description, the same reference reference numerals will be given to the components common to each embodiment, and the repeated description will be omitted.

FIG. 1 is a block diagram showing a configuration of a fan according to an embodiment of the present invention.

The fan 100 according to the present embodiment is a device that generates wind by rotating an impeller (impeller). The fan 100 can be used as one of the cooling devices for discharging the heat generated inside the device to the outside and cooling the inside of the device. The fan 100 is, for example, an axial fan.

As shown in FIG. 1, the fan 100 includes a motor 20, a motor drive control device 1 for driving the motor 20, and an impeller 21 configured to be rotatable by the rotational force of the motor 20.

In the present embodiment, the motor 20 is, for example, a three-phase brushless motor having coils Lu, Lv, and Lw. The motor drive control device 1 is a device for controlling the rotation of the motor 20. The motor drive control device 1 rotates the motor 20 by periodically passing a drive current through the three-phase coils Lu, Lv, and Lw constituting the motor 20.

Specifically, the motor drive control device 1 includes a motor drive unit 2, a control circuit unit 4, and a current detection unit 6. The components of the motor drive control device 1 shown in FIG. 1 are a part of the whole, and the motor drive control device 1 has other components in addition to those shown in FIG. You may be doing it.

In the present embodiment, at least a part of the motor drive control device 1 is packaged as one semiconductor device (IC: Integrated Circuit). For example, circuits such as the control circuit unit 4 and the motor drive unit 2 are realized as separate semiconductor devices.

The motor drive control device 1 may be a semiconductor device in which all of the motor drive control device 1 is packaged, or a whole or a part of the motor drive control device 1 and another device are packaged together to form one. It may constitute a semiconductor device.

The motor drive unit 2 outputs a drive signal to the motor 20 based on the drive control signal Sd output from the control circuit unit 4, and drives the motor 20. The motor drive unit 2 selectively energizes the multi-phase coils Lu, Lv, and Lw of the motor 20.

Specifically, the motor drive unit 2 has an inverter circuit 2a and a predrive circuit 2b. The predrive circuit 2b generates an output signal for driving the inverter circuit 2a based on the drive control signal Sd output from the control circuit unit 4, and outputs the output signal to the inverter circuit 2a. The inverter circuit 2a energizes the coils Lu, Lv, and Lw included in the motor 20 based on the signal output from the predrive circuit 2b.

Specifically, in the inverter circuit 2a, for example, a pair of a series circuit of two switching elements provided at both ends of the power supply voltage (DC power supply) Vcc is each phase (U phase, V) of the coils Lu, Lv, and Lw. It is arranged and configured for each phase (phase, W phase). In each pair of the two switching elements, the terminals of each phase of the motor 20 are connected to the connection points between the switching elements (not shown). The predrive circuit 2b outputs, for example, six types of signals Vuu, Vul, Vvu, Vvl, Vwoo, and Vwl corresponding to each switching element of the inverter circuit 2a as output signals. By outputting these signals Vuu, Vul, Vvu, Vvl, Vwoo, and Vwl, the switching elements corresponding to the respective signals Vuu, Vul, Vv, Vvl, Vwoo, and Vwl operate on and off. As a result, a drive signal is output to the motor 20, and a current flows through the coils Lu, Lv, and Lw of each phase of the motor 20 (not shown).

The current detection unit 6 is a functional unit for detecting the current flowing through the motor 20, that is, the current flowing through the coils Lu, Lv, and Lw of the motor 20 (hereinafter, also referred to as “motor current”). The current detection unit 6 outputs a voltage Vs corresponding to the motor current of the motor 20. The configuration of the current detection unit 6 will be described later.

The control circuit unit 4 is composed of, for example, a microcomputer, a digital circuit, an analog circuit, and the like. Various signals instructing the driving of the motor 20 are input to the control circuit unit 4. The control circuit unit 4 controls the drive of the motor 20 based on these signals. For example, as a signal instructing the drive of the motor 20, a speed command signal Sc is input to the control circuit unit 4 from a device provided outside the control circuit unit 4 such as a host device.

The speed command signal Sc is a signal related to the rotation speed of the motor 20. For example, the speed command signal Sc is a PWM (pulse width modulation) signal having a duty ratio corresponding to the target rotation speed Rtg of the motor 20. A clock signal may be input as the speed command signal Sc.

Further, the position detection signal Sh is input from the position detection element 5 to the control circuit unit 4. The position detection element 5 is, for example, a Hall element arranged in the motor 20, and the position detection signal Sh is a Hall signal output from the Hall element 5. The position detection signal Sh is a signal indicating the rotation position of the motor 20, that is, a signal corresponding to the rotation of the rotor (not shown) of the motor 20. Hereinafter, the position detection element 5 is also referred to as a “Hall element 5”.

The control circuit unit 4 obtains information on the actual rotation speed of the rotor of the motor 20 from the position detection signal Sh, and controls the drive of the motor 20.

Although FIG. 1 illustrates a case where one Hall element 5 is arranged on the fan 100, the number of Hall elements 5 arranged on the fan 100 is not particularly limited. For example, the three Hall elements 5 may be arranged around the rotor of the motor 20 at substantially equal intervals from each other.

The control circuit unit 4 may be configured to input other information regarding the rotational state of the motor 20 in addition to the position detection signal Sh or instead of the position detection signal Sh. .. For example, as the FG signal corresponding to the rotation of the rotor of the motor 20, a signal (pattern FG) generated by using the coil pattern provided on the substrate on the rotor side may be input. Further, even if the rotation state of the motor 20 is detected based on the detection result of the rotation position detection circuit that detects the counter electromotive voltage induced in each phase (U, V, W phase) of the motor 20. Good. An encoder, a resolver, or the like may be provided so that information such as the rotation speed of the motor 20 can be detected.

The control circuit unit 4 generates a drive control signal Sd for controlling the rotation speed of the motor 20 based on the speed command signal Sc, the position detection signal Sh, the voltage Vs, and the like described above.

The drive control signal Sd is, for example, a PWM (pulse width modulation) signal. The control circuit unit 4 supplies the drive control signal Sd, which is a PWM (pulse width modulation) signal, to the motor drive unit 2, and thereby energizes the multi-phase coils Lu, Lv, and Lw that are energized by the motor drive unit 2. The air volume of the fan 100 is controlled by adjusting the rotation speed of the motor 20 while switching the above in a predetermined order.

The motor drive control device 1 according to the present embodiment controls the rotation speed of the motor 20 so that the air volume of the fan 100 is limited in a region where the static pressure of the fan 100 is equal to or less than a predetermined value.

FIG. 2 is a diagram for explaining air volume control of the fan 100 by the motor drive control device 1 according to the present embodiment.

In FIG. 2, the horizontal axis represents the air volume Q and the vertical axis represents the static pressure P. FIG. 2 shows PQ curves for each target rotation speed Rtg when the target rotation speed Rtg indicated by the speed command signal Sc is changed.

In FIG. 2, reference numeral 201_min represents the PQ curve of the fan 100 when the target rotation speed Rtg is set to the minimum value Rmin, and reference numeral 201_max is when the target rotation speed Rtg is set to the maximum value Rmax. The PQ curve of the fan 100 is represented, and the reference reference numeral 201_x represents the PQ curve when the target rotation speed Rtg is set to a value between the maximum value and the minimum value.

As mentioned above, the fan is designed to provide the desired airflow within the required operating range. For example, in FIG. 2, it is assumed that the operating range required for the fan is the range indicated by the reference numeral 200. In this case, the fan having the PQ curve shown in FIG. 2 has a region where the requested operating range 200 is lower than the PQ curve when the target rotation speed is set to the maximum value Rtg_max (region where the static pressure is low). ), So it can be said that it satisfies the required specifications.

On the other hand, as described above, in a region other than the required operating range, that is, in a region where the static pressure is equal to or less than a predetermined value, the quietness of the fan is more important than the air volume. For example, in FIG. 2, in the region where the static pressure is Pb or less, quietness is more important than air volume.

However, the conventional fan controls the rotation speed of the motor so as to reach the target rotation speed indicated by the speed command signal Sc, and the air volume changes depending on the pressure loss (static pressure). Therefore, the air volume tends to increase and the noise tends to increase even in a region where the static pressure is low.

For example, consider the case where a conventional fan is designed to operate on the PQ curve indicated by reference numeral 201_max, as shown in FIG. In this case, when the target rotation speed is set to "Rtg_max" in the free air state, the conventional fan generates an air volume qmax that greatly exceeds the air volume qr1 to qr2 range required in the operating range 200.

However, as described above, in the region other than the operating range 200, an air volume that greatly exceeds the required air volume qr1 to qr2 range is unnecessary.

Therefore, in the motor drive control device 1 according to the present embodiment, the air volume of the fan 100 is limited in a region where the static pressure is lower than a predetermined value, regardless of the target rotation speed Rtg instructed by the speed command signal Sc. , Control the rotation speed of the motor 20.

Specifically, as shown in FIG. 2, in the motor drive control device 1, the target rotation speed Rtg becomes a predetermined value Rx (minimum value Rmin <Rx <maximum value Rmax) in a range where the static pressure is lower than the predetermined value Pb. A line connecting the point A of the maximum air volume when it is set to the point B of the maximum air volume when the target rotation speed Rtg is set to the maximum value Rmax (hereinafter, also referred to as "maximum air volume control line") C. The air volume of the fan 100 is controlled so as to be in line with.

More specifically, the motor drive control device 1 adjusts the rotation speed of the motor 20 based on the correspondence between the rotation speed of the motor 20 and the motor current in the maximum air volume control line C, so that the static pressure becomes a predetermined value. In the range lower than Pb, the air volume of the fan 100 is controlled so as to be along the maximum air volume control line C.

FIG. 3 is a diagram showing a correspondence relationship between the rotation speed of the motor 20 and the motor current in the maximum air volume control line C of FIG.
The characteristic (graph) 500 shown in FIG. 3 represents the relationship between the rotation speed (actual rotation speed Rr) and the motor current (actual current value Ir) of the motor 20 in the maximum air volume control line C of FIG. Point A in the characteristic 500 of FIG. 3 corresponds to point A in the maximum air volume control line C of FIG. 2, and point B in the characteristic 500 of FIG. 3 corresponds to point B in the maximum air volume control line C of FIG. There is.

The characteristic 500 can be obtained by the method shown below.
For example, the static pressure (P), air volume (Q), and motor at each target rotation speed when the target rotation speed Rtg of the fan 100 (motor 20) is changed from the settable minimum value Rmin to the settable maximum value Rmax. The rotation speed of 20 (actual rotation speed Rr) and the motor current (actual current value Ir) are measured in advance. At this time, the maximum air volume control described later of the fan 100 is disabled.

Next, using the measurement data of the static pressure (P) and the air volume (Q), a PQ curve is drawn for each target rotation speed as shown in FIG. Next, using the drawn PQ curve, the maximum air volume control line C is set so that the air volume is limited in a region where the static pressure is lower than a desired value (for example, Pb). The method of setting the maximum air volume control line C is as described above.

Next, the measurement data of the actual rotation speed Rr and the actual current value Ir in the maximum air volume control line C are extracted from the measurement data of the actual rotation speed Rr of the motor 20 and the actual current value Ir of the motor current at each target rotation speed. To do. Then, based on the extracted measurement data, the correspondence between the actual rotation speed Rr and the actual current value Ir is plotted. As a result, the characteristic 500 representing the correspondence between the rotation speed of the motor 20 and the motor current can be obtained.

As described above, the characteristic 500 represents the relationship between the rotation speed of the motor 20 and the motor current when the fan 100 operates along the maximum air volume control line C of the PQ curve shown in FIG. .. Therefore, by controlling the rotation speed and the motor current of the motor 20 so as to satisfy the characteristic 500, the fan 100 can be operated along the maximum air volume control line C.

Therefore, in the motor drive control device 1 according to the present embodiment, the actual current value of the motor current of the motor 20 is set to the target value of the motor current represented by the characteristic 500 (hereinafter, referred to as “target current value Itg”). By adjusting the rotation speed of the motor 20 so as to approach, the fan 100 is operated along the maximum air volume control line C to limit the maximum air volume of the fan 100.

Hereinafter, the configuration of the motor drive control device 1 for realizing the function for limiting the maximum air volume of the fan 100 will be described in detail.

FIG. 4 is a block diagram showing a configuration of the motor drive control device 1 according to the present embodiment.
FIG. 4 shows a functional block related to the above-mentioned function for limiting the maximum air volume of the fan 100 among the functional blocks constituting the motor drive control device 1.

When the target rotation speed Rtg of the motor 20 specified by the speed command signal Sc is lower than the threshold Rth (for example, when Rtg <Rth), the control circuit unit 4 in the motor drive control device 1 rotates the motor 20. Speed feedback control is performed to generate a drive control signal Sd so that (actual rotation speed Rr) matches the target rotation speed Rtg.

On the other hand, when the target rotation speed Rtg is higher than the threshold Rth (for example, when Rtg ≧ Rth), the control circuit unit 4 determines that the current (motor current) flowing through the motor 20 is the rotation speed (actual rotation speed) of the motor 20. The maximum air volume control for generating the drive control signal Sd is performed so as to approach the target current value Itg calculated in response to.

Specifically, the control circuit unit 4 includes a target rotation speed acquisition unit 41, a rotation speed calculation unit 42, a speed control unit 43, and a maximum air volume control unit 44 as functional blocks for realizing speed feedback control and maximum air volume control. It has a drive control signal generation unit 45, a current value acquisition unit 46, a target current value calculation unit 47, and a comparison unit (CMP) 48.

The target rotation speed acquisition unit 41 acquires information on the target rotation speed Rtg of the motor 20 from, for example, a speed command signal Sc output from a higher-level device existing outside the motor drive control device 1, and the speed control unit 43 and the maximum air volume. It is given to the control unit 44.

For example, when the speed command signal Sc is a PWM signal representing the target rotation speed Rtg by the duty ratio, the target rotation speed acquisition unit 41 analyzes the duty ratio of the PWM signal as the input speed command signal Sc, and the target rotation speed acquisition unit 41 analyzes the duty ratio. The rotation speed corresponding to the duty ratio is calculated and output as the target rotation speed Rtg. For example, the target rotation speed acquisition unit 41 has a table showing the correspondence between the duty ratio of the PWM signal and the target rotation speed, and the target rotation speed acquisition unit 41 has the duty ratio of the input speed command signal Sc. By reading the target rotation speed corresponding to the above table from the above table, the information of the target rotation speed Rtg is acquired from the speed command signal Sc.

The target rotation speed acquisition unit 41 is realized by, for example, an external interface circuit of a microcontroller and a program process of a CPU.

The rotation speed calculation unit 42 calculates the rotation speed (rotation speed per unit time) of the motor 20 based on the position detection signal Sh output from the position detection element 5. The rotation speed calculation unit 42 calculates the actual rotation speed of the rotor of the motor 20 using the position detection signal Sh, and gives the actual rotation speed Rr to the speed control unit 43 and the target current value calculation unit 47.

The rotation speed calculation unit 42 is realized by, for example, the external interface circuit of the microcontroller and the program processing of the CPU, similarly to the target rotation speed acquisition unit 41.

The speed control unit 43 is PWM as a drive control signal Sd based on the target rotation speed Rtg output from the target rotation speed acquisition unit 41 and the actual rotation speed Rr of the motor 20 calculated by the rotation speed calculation unit 42. A PWM command signal (an example of a first control signal) Sp1 that specifies the duty ratio of the signal is generated.

Specifically, the speed control unit 43 generates the PWM command signal Sp1 so that the actual rotation speed Rr matches the target rotation speed Rtg. For example, the speed control unit 43 calculates the difference between the actual rotation speed Rr and the target rotation speed Rtg, and calculates the duty ratio of the PWM signal as the drive control signal Sd so that the difference becomes zero. Then, the speed control unit 43 outputs the calculated duty ratio information as a PWM command signal Sp1.

The current value acquisition unit 46 is a functional unit that calculates the current value of the current flowing through the motor 20. The current value acquisition unit 46 includes, for example, an A / D conversion circuit that converts an analog signal into a digital signal. For example, the current value acquisition unit 46 is a delta-sigma modulation type analog / digital conversion circuit, and is composed of a dedicated logic circuit. The current value acquisition unit 46 converts the analog signal input from the current detection unit 6 into a digital signal by the ΔΣ modulation method.

Here, as described above, the current detection unit 6 is a circuit that outputs a voltage Vs corresponding to the current (motor current) flowing through the motor 20 as a control target. For example, as shown in FIG. 3, the current detection unit 6 includes a resistor Rs connected in series between the coils Lu, Lv, Lw of the motor 20 and the ground potential via the motor drive unit 2, and the resistance Rs. The voltage Vs generated at both ends is output as a detected value of the motor current of the motor 20.

The current value acquisition unit 46 converts the voltage Vs, which is an analog signal output from the current detection unit 6, into a digital signal, and outputs it as the actual current value Ir of the motor current of the motor 20.

The target current value calculation unit 47 calculates the target current value Itg based on the actual rotation speed Rr calculated by the rotation speed calculation unit 42. For example, the target current value calculation unit 47 has a storage unit 470 that stores the correspondence information 471 representing the correspondence relationship between the rotation speed of the motor 20 and the motor current, and the correspondence information 471 read from the storage unit 470. Is used to calculate the target current value Itg from the actual rotation speed Rr.

As described above, the target current value Itg is a target value of the motor current for controlling the air volume of the fan 100 along the maximum air volume control line C.

Correspondence information 471 is, for example, information including a mathematical formula representing the characteristic 500 of FIG. For example, by performing regression analysis in advance using the measurement data of the actual rotation speed Rr and the actual current value Ir of the motor 20 in the maximum air volume control line C, a relational expression (for example, a linear function) between the rotation speed and the motor current can be obtained. It is derived, and the derived relational expression is stored in advance in the storage unit 470 as the correspondence relation information 471.

In the maximum air volume control, the target current value calculation unit 47 reads out the relational expression between the rotation speed and the motor current as the correspondence information 471 from the storage unit 470, and the rotation speed calculation unit 42 calculates the relational expression of the motor 20. By substituting the actual rotation speed Rr, the target current value Itg of the motor 20 is calculated.

The correspondence information 471 is not limited to the above-mentioned relational expression, and may be, for example, a table (look-up table) showing the correspondence between the motor current and the rotation speed.

The comparison unit 48 compares the target rotation speed Rtg with the threshold value Rth and outputs the comparison result.

The threshold value Rth is a parameter that serves as a reference for switching the control mode (speed feedback control and maximum air volume control) of the fan 100. For example, when the fan 100 is controlled along the maximum air volume control line C shown in FIG. 2, the rotation speed of the motor 20 at the point A may be set as the threshold value Rth.

When the target rotation speed Rtg output from the target rotation speed acquisition unit 41 is larger than the threshold value Rth, the comparison unit 48 outputs, for example, a high level determination signal Scmp. On the other hand, the comparison unit 48 outputs, for example, a low level determination signal Scmp when the target rotation speed Rtg output from the target rotation speed acquisition unit 41 is smaller than the threshold value Rth.

The maximum air volume control unit 44 generates a PWM command signal (an example of a second control signal) Sp2 that specifies the duty ratio of the PWM signal as the drive control signal Sd based on the determination signal Scmp of the comparison unit 48. Specifically, the maximum air volume control unit 44 PWMs so that the actual current value Ir of the motor current approaches the target current value Itg when the comparison unit 48 determines that the target rotation speed Rtg is higher than the predetermined threshold value Rth. The command signal Sp2 is generated. On the other hand, when the comparison unit 48 determines that the target rotation speed Rtg is lower than the predetermined threshold value Rth, the maximum air volume control unit 44 does not generate the PWM command signal Sp2.

The maximum air volume control unit 44 generates the PWM command signal Sp2 based on the target current value Itg calculated by the target current value calculation unit 47 and the actual current value Ir calculated by the current value acquisition unit 46.

Specifically, the maximum air volume control unit 44 generates a PWM command signal Sp2 so that the rotation speed Rr of the motor 20 increases when the actual current value Ir is higher than the target current value Itg, and the actual current value Ir becomes When the current value is lower than the target current value Itg, the PWM command signal Sp2 is generated so that the rotation speed Rr of the motor 20 decreases.

More specifically, the maximum air volume control unit 44 increases the rotation speed of the motor 20 when the actual current value Ir of the motor 20 is higher than a predetermined range based on the target current value Itg, and the actual current value Ir becomes. When it is within the predetermined range, the rotation speed of the motor 20 is not changed, and when the actual current value Ir is lower than the predetermined range, the PWM command signal Sp2 is generated so as to reduce the rotation speed of the motor.

5A and 5B are diagrams for explaining maximum air volume control. FIG. 5A shows an example of a method of adjusting the rotation speed of the motor 20 based on the actual current value Ir of the motor current, and FIG. 5B shows an example of the method of adjusting the operating point of the motor 20 based on the target current value Itg. An example is shown.
In FIG. 5A, | X | <| Y |, | Z |.

For example, as shown in FIG. 5A, when Itg-X <Ir <Itg + X, that is, when the actual current value Ir of the motor current is in the range Mm, the maximum air volume control unit 44 determines the rotation speed of the motor 20. Does not change. For example, in FIG. 5B, when the motor 20 is operating at the operating point c, it can be determined that the fan 100 is operating along the maximum air volume control line C. In this case, the maximum air volume control unit 44 outputs the PWM command signal Sp2 including the information of the same duty ratio as the PWM command signal Sp2 output immediately before.

On the other hand, when Ir> Itg + Z, that is, when the actual current value Ir of the motor current is in the range H, the maximum air volume control unit 44 generates the PWM command signal Sp2 so as to reduce the rotation speed of the motor 20. For example, in FIG. 5B, when the motor 20 is operating at the operating point a, it can be determined that the fan 100 is not operating along the maximum air volume control line C (the pressure resistance to the fan 100 is large). In this case, as shown in FIG. 5B, the maximum air volume control unit 44 increases the rotational speed of the motor 20 so as to shift the operating point of the fan 100 from “a” to “ax” on the characteristic 500. Generates PWM command signal Sp2. For example, when the duty ratio specified by the PWM command signal Sp2 output immediately before is 50% and the unit adjustment range of the duty ratio is 0.1%, the maximum air volume control unit 44 is set to "(50-0. 1) The PMW command signal Sp2 indicating the duty ratio of "%" is output.

Further, when Ir <Itg-Y, that is, when the actual current value Ir of the motor current is in the range L, the maximum air volume control unit 44 generates the PWM command signal Sp2 so as to reduce the rotation speed of the motor 20. To do. For example, in FIG. 5B, when the motor 20 is operating at the operating point b, it can be determined that the fan 100 is not operating along the maximum air volume control line C (the pressure resistance to the fan 100 is small). In this case, as shown in FIG. 5B, the maximum air volume control unit 44 reduces the rotation speed of the motor 20 so as to shift the operating point of the fan 100 from “b” to “bx” on the characteristic 500. Generates PWM command signal Sp2. For example, when the duty ratio specified by the PWM command signal Sp2 output immediately before is 50% and the unit adjustment range of the duty ratio is 0.1%, the maximum air volume control unit 44 is set to "(50 + 0.1). % ”Duty ratio indicates PMW command signal Sp2 is output.

As shown in FIG. 5A, in the range Mh where Itg + X <Ir <Itg + Z and the range Ml where Itg-Y <Ir <Itg-X, the range Mm where Itg-X <Ir <Itg + X is the same. The maximum air volume control unit 44 may be controlled so as not to change the rotation speed of the motor 20. As a result, in the maximum air volume control, the range of the operating points of the motor 20 that does not change the rotation speed can be expanded from the range Mm to the range M (= Mh + Mm + Ml). It should be noted that | Y | = | Z | or | Y | ≠ | Z | may be used.

The drive control signal generation unit 45 is a functional unit that generates a drive control signal Sd for controlling the drive of the motor 20. The drive control signal generation unit 45 generates a drive control signal Sd based on the PWM command signal Sp1 output from the speed control unit 43 and the PWM command signal Sp2 output from the maximum air volume control unit 44.

Specifically, when the comparison unit 48 determines that the target rotation speed Rtg is smaller than the threshold value Rth, the drive control signal generation unit 45 has a duty ratio specified by the PWM command signal Sp1 output from the speed control unit 43. PWM signal is generated and output as a drive control signal Sd. On the other hand, when the comparison unit 48 determines that the target rotation speed Rtg is larger than the threshold value Rth, the drive control signal generation unit 45 has a duty ratio of the duty ratio specified by the PWM command signal Sp2 output from the maximum air volume control unit 44. A PWM signal is generated and output as a drive control signal Sd.

For example, when the PWM command signal Sp2 is not output from the maximum air volume control unit 44, the drive control signal generation unit 45 is a PWM signal having a duty ratio specified by the PWM command signal Sp1 output from the speed control unit 43. Is generated and output as a drive control signal Sd, and when the PWM command signal Sp2 is output from the maximum air volume control unit 44, the PWM command signal output from the maximum air volume control unit 44 instead of the PWM command signal Sp1 A PWM signal with a duty ratio specified in Sp2 is generated and output as a drive control signal Sd.

The speed control unit 43, the maximum air volume control unit 44, the drive control signal generation unit 45, the target current value calculation unit 47, and the comparison unit 48 described above are realized by, for example, program processing of a microcontroller (CPU). The drive control signal generation unit 45 may be realized by a dedicated logic circuit.

Next, the flow of the air volume control method for the fan 100 will be described.
FIG. 6 is a flow chart showing a flow of air volume control of the fan 100 by the motor drive control device 1 according to the embodiment.

First, when the speed command signal Sc is input to the control circuit unit 4 from the host device, the target rotation speed acquisition unit 41 of the control circuit unit 4 acquires the information of the target rotation speed Rtg from the speed command signal Sc (step). S1).

Next, the control circuit unit 4 determines whether or not the target rotation speed Rtg acquired in step S1 is larger than the threshold value Rth by the comparison unit 48 (step S2). When the target rotation speed Rtg is smaller than the threshold value Rth (step S2: No), the control circuit unit 4 performs speed feedback control (step S3). That is, as described above, the drive control signal generation unit 45 generates the drive control signal Sd based on the PWM command signal Sp1 generated by the speed control unit 43, so that the actual rotation speed Rr of the motor 20 is targeted. The motor 20 operates so as to match the rotation speed Rtg. At this time, the maximum air volume control unit 44 does not generate the PWM command signal Sp2.

On the other hand, in step S2, when the target rotation speed Rtg is larger than the predetermined threshold value Rth (step S2: Yes), the control circuit unit 4 starts the maximum air volume control (step S4).

In the maximum air volume control, first, the control circuit unit 4 acquires information on the actual rotation speed Rr of the motor 20 (step S5). That is, as described above, the target current value calculation unit 47 acquires the information of the actual rotation speed Rr of the motor 20 calculated by the rotation speed calculation unit 42.

Next, the target current value calculation unit 47 calculates the target current value Itg (step S6). Specifically, the target current value calculation unit 47 uses the above-described method based on the information of the actual rotation speed Rr acquired in step S5 and the correspondence information 471 stored in the storage unit 470 to obtain the target current value. Calculate Itg.

Next, the maximum air volume control unit 44 acquires the actual current value Ir of the motor 20 (step S7). Specifically, as described above, the maximum air volume control unit 44 acquires the information of the actual current value Ir of the motor current calculated by the current value acquisition unit 46.

Next, the maximum air volume control unit 44 determines whether or not Itg-X <Ir <Itg + X, that is, whether or not the actual current value Ir acquired in step S7 is in the range M (step S8).

In step S8, when the actual current value Ir is in the range M (step S8: Yes), the maximum air volume control unit 44 does not change the rotation speed of the motor 20 (step S13). For example, the maximum air volume control unit 44 outputs the PWM command signal Sp2 showing the same duty ratio as the PWM command signal Sp2 output immediately before.

On the other hand, in step S8, when the actual current value Ir is not in the range M (step S8: No), the maximum air volume control unit 44 determines whether or not Ir <Itg-Y, that is, the actual current value Ir is in the range. It is determined whether or not it is in L (step S9).

In step S9, when the actual current value Ir is in the range L (step S9: Yes), the maximum air volume control unit 44 increases the rotation speed of the motor 20 (step S11). For example, the maximum air volume control unit 44 outputs a PWM command signal Sp2 indicating a duty ratio increased by a predetermined width (for example, 0.1%) from the duty ratio indicated by the PWM command signal Sp2 output immediately before.

On the other hand, in step S9, when the actual current value Ir is not in the range L (step S9: No), the maximum air volume control unit 44 determines whether or not Itg + Z <Ir, that is, the actual current value Ir is in the range H. It is determined whether or not there is (step S10).

In step S10, when the actual current value Ir is in the range H (step S10: Yes), the maximum air volume control unit 44 reduces the rotation speed of the motor 20 (step S12). For example, the maximum air volume control unit 44 outputs a PWM command signal Sp2 indicating a duty ratio that is reduced by a predetermined width (for example, 0.1%) from the duty ratio indicated by the PWM command signal Sp2 output immediately before.

On the other hand, when the actual current value Ir is not in the range H (step S10: No) in step S10, the maximum air volume control unit 44 is Itg + X <Ir <Itg + Z or Itg-X <Ir <Itg-Y. That is, it is determined that Itg is in the range Mh or Ml, and the rotation speed of the motor 20 is not changed (step S13).

After steps S11 to S13, the control circuit unit 4 generates a drive control signal Sd based on the PWM command signal Sp2 (step S14). Specifically, the drive control signal generation unit 45 generates a PWM signal having a duty ratio specified by the PWM command signal Sp2 output from the maximum air volume control unit 44 in steps S11 to S13, and outputs the PWM signal as the drive control signal Sd. To do.

After steps S3 and S14, the control circuit unit 4 determines whether or not there is an instruction to stop the motor 20 (step S15). In step S15, when there is no instruction to stop the motor 20 (step S15: No), the above-mentioned processes (S1 to S15) are repeatedly executed. On the other hand, when the instruction to stop the motor 20 is received in step S15 (step S15: Yes), the control circuit unit 4 ends the air volume control process.

FIG. 7 is a diagram showing the relationship between the rotation speed of the motor and the target rotation speed in the fan according to the present embodiment.
In FIG. 7, the horizontal axis represents the target rotation speed Rtg, and the vertical axis represents the actual rotation speed Rr of the motor 20.

As shown in FIG. 7, the conventional fan controls the motor so that the rotation speed matches the target rotation speed Rtg as shown by reference numeral 600. That is, since the conventional fan controls the motor so that the air volume increases in proportion to the target rotation speed Rtg, for example, as shown by the PQ curve indicated by the reference numeral 201_max in FIG. 2, the static pressure (pressure). Even in the region where the resistance) is low, the air volume increases in proportion to the target rotation speed Rtg.

On the other hand, in the fan 100 according to the present embodiment, in the range where the target rotation speed Rtg is lower than the threshold Rth, the motor 20 so that the rotation speed of the fan (motor) matches the target rotation speed Rtg as in the conventional fan. However, in the range where the target rotation speed Rtg is higher than the threshold Rth, as shown by reference numeral 601 so that the rotation speed does not exceed the set maximum rotation speed, that is, the threshold Rth, regardless of the target rotation speed Rtg. Controls the motor 20.

That is, in the range where the target rotation speed Rtg is higher than the threshold value Rth, the fan 100 according to the present embodiment is a motor from the relationship between the rotation speed on the maximum air volume control line C shown in FIG. 2 and the motor current, as described above. The target current value Itg corresponding to the actual rotation speed of 20 is calculated, and the rotation speed of the motor 20 is controlled so that the motor current approaches the target current value Itg. Thereby, the fan 100 can limit the maximum air volume in the region where the static pressure is low (the range where the static pressure in the PQ curve of FIG. 2 is lower than Pb).

As described above, in the motor drive control device 1 according to the present embodiment, when the target rotation speed Rtg instructed by the speed command signal Sc is lower than the threshold Rth, the rotation speed of the motor 20 matches the target rotation speed Rtg. When speed feedback control for generating the drive control signal Sd is performed and the target rotation speed Rtg is higher than the threshold Rth, the actual current value Ir of the motor 20 is the target current value Itg calculated in response to the rotation speed of the motor 20. The maximum air volume control that generates the drive control signal Sd so as to approach is performed. The maximum air volume control in the present invention is controlled so that the maximum air volume becomes a desired value according to the relationship between the rotation speed of the motor 20 and the pressure loss when the target rotation speed Rtg is higher than the threshold value Rth. It is a thing, and it is not necessarily controlled so as to keep the air volume constant. Therefore, the maximum air volume control of the present invention is different from the conventional so-called constant air volume control in the control method and its effect.

According to this, as described above, in the range where the target rotation speed Rtg is lower than the threshold Rth, the motor 20 is driven so that the air volume of the fan 100 increases in proportion to the indicated target rotation speed Rtg. In the range where the target rotation speed Rtg is higher than the threshold Rth, the motor 20 is driven so that the air volume of the fan 100 changes according to the static pressure.

Specifically, as described above, in the range where the target rotation speed Rtg is higher than the threshold value Rth, the motor drive control device 1 provides the correspondence information 471 between the rotation speed of the motor 20 and the target current value Itg stored in advance. The target current value Itg corresponding to the actual rotation speed Rr of the motor 20 calculated based on the position detection signal (Hall signal) Sh of the motor 20 is calculated, and the actual current value Ir of the motor 20 becomes the target current value Itg. The rotation speed of the motor 20 is controlled so as to approach.

Here, the static pressure of the fan 100 is determined by using the correspondence information 471 as information indicating the relationship between the rotation speed of the motor 20 and the target current value Itg in a region where the static pressure of the fan 100 is lower than the predetermined value. In the region lower than the value, the rotation speed of the motor 20 is adjusted so as to satisfy the relationship between the rotation speed of the motor 20 and the target current value Itg specified in the correspondence information 471, regardless of the specified target rotation speed Rtg. Be controlled. For example, by setting the correspondence information 471 so as to satisfy the characteristics on the maximum air volume control line C in the PQ curve shown in FIG. 2, it is designated in the region where the static pressure of the fan 100 is lower than Pb. The air volume can be controlled so as to satisfy the maximum air volume control line C regardless of the target rotation speed Rtg.

That is, according to the motor drive control device 1 according to the present embodiment, in a region where the static pressure is higher than the predetermined value, a sufficient air volume can be secured in the required operating range, and the static pressure is lower than the predetermined value. In the region, the air volume can be suppressed regardless of the designated target rotation speed Rtg, and the generation of noise of the fan 100 and the increase in power consumption can be suppressed.

Further, the motor drive control device 1 according to the present embodiment has a drive control signal so that the rotation speed of the motor 20 increases when the actual current value Ir of the motor 20 is higher than the target current value Itg in the maximum air volume control. Sd is generated, and when the actual current value Ir of the motor 20 is lower than the target current value Itg, the drive control signal Sd is generated so that the rotation speed of the motor 20 decreases.

According to this, when the instructed target rotation speed Rtg is higher than the threshold value Rth, as shown in FIG. 5B, the operating point of the motor 20 has the characteristic 500 between the actual current value Ir of the motor 20 and the actual rotation speed Rr. It becomes easy to control to satisfy.

Further, in the maximum air volume control, the motor drive control device 1 increases the rotation speed of the motor 20 when the actual current value Ir of the motor 20 is higher than the range Mm with respect to the target current value Itg, and the actual current value of the motor 20 is increased. A drive control signal that does not change the rotation speed of the motor 20 when the current value Ir is within the range Mm and reduces the rotation speed of the motor 20 when the actual current value Ir of the motor 20 is lower than the range Mm. Generate Sd.

According to this, when the operating point of the motor 20 approaches the maximum air volume control line C, it is possible to prevent the air volume of the fan 100 from becoming unstable due to an excessive change in the rotation speed. ..

In particular, as shown in FIGS. 5A and 5B, in the maximum air volume control, the range of operating points that do not change the rotation speed of the motor 20 is expanded from the range Mm to the range M (= Mh + Mm + Ml), so that the rotation speed is excessive. It is possible to prevent such changes more effectively, and it is possible to further stabilize the air volume of the fan 100.

≪Expansion of embodiment≫
The inventions made by the present inventors have been specifically described above based on the embodiments, but it goes without saying that the present invention is not limited thereto and can be variously modified without departing from the gist thereof. No.

For example, in the above embodiment, the case where the relational expression or table representing the characteristic 500 between the motor current and the rotation speed on the maximum air volume control line C is used as the correspondence relation information 471 is exemplified, but the present invention is not limited to this. .. For example, the characteristic 500 may be used as a reference, a correction may be made by adding or subtracting an offset amount to the reference, and a relational expression, a table, or the like representing the corrected characteristic may be used as the correspondence relation information 471.

Further, in the above embodiment, as shown in FIG. 5A, a case where the rotation speed of the motor 20 is not changed in the range Mh and the range Ml is illustrated, but the present invention is not limited to this. For example, in the range Mh and the range Ml, the rotation speed of the motor 20 may be reduced by an adjustment width smaller than the adjustment width of the range H and the range L. For example, when the adjustment range of the duty ratio of the drive control signal Sd in the range H and the range L is "± 0.5%", the adjustment range of the duty ratio of the drive control signal Sd in the range Mh and the range Ml is "± 0.5%". It may be "0.1%".

Further, in the above embodiment, the case where the speed command signal Sc is a PWM signal and the target rotation speed is specified by the duty ratio of the PWM signal has been illustrated, but the present invention is not limited to this. For example, the speed command signal Sc is an analog signal, and the target rotation speed may be specified by the voltage level of the analog signal.

Further, in the above embodiment, the case where the motor 20 is a three-phase brushless motor is illustrated, but the type and the number of phases of the motor 20 are not limited to this. For example, it may be a single-phase brushless motor.

Further, the above-mentioned flowchart shows an example for explaining the operation, and is not limited thereto. That is, the steps shown in each figure of the flowchart are specific examples, and are not limited to this flow. For example, the order of some processes may be changed, other processes may be inserted between each process, and some processes may be performed in parallel.

1 ... Motor drive control device, 2 ... Motor drive unit, 2a ... Inverter circuit, 2b ... Predrive circuit, 4 ... Control circuit unit, 5 ... Position detection element (Hall element), 6 ... Current detection unit, 20 ... Motor, 21 ... Impeller, 41 ... Target rotation speed acquisition unit, 42 ... Rotation speed calculation unit, 43 ... Speed control unit, 44 ... Maximum air volume control unit, 45 ... Drive control signal generation unit, 46 ... Current value acquisition unit, 47 ... Target Current value calculation unit, 470 ... Storage unit, 471 ... Correspondence relation information, 48 ... Comparison unit, 100 ... Fan, Lu, Lv, Lw ... Coil, H, L, M, Ml, Mm, Mh ... Range, Sc ... Speed Command signal, Scmp ... Judgment signal, Sd ... Drive control signal, Sp1 ... PWM command signal (example of first control signal), Sp2 ... PWM command signal (example of second control signal), Sh ... Position detection signal, Vcc ... Power supply voltage, Vs ... voltage, Rtg ... target rotation speed, Rth ... threshold, Rr ... actual rotation speed, Itg ... target current value, Ir ... actual current value.

Claims (8)

A control circuit unit that generates a drive control signal for controlling the rotation speed of the motor based on a speed command signal that indicates a target rotation speed of the motor.
A motor drive unit that drives the motor based on the drive control signal is provided.
The control circuit unit
When the target rotation speed is lower than the threshold value, speed feedback control for generating the drive control signal is performed so that the rotation speed of the motor matches the target rotation speed, and when the target rotation speed is higher than the threshold value. A motor drive control device that controls the maximum air volume to generate the drive control signal so that the current flowing through the motor approaches the target current value calculated in response to the rotation speed of the motor. In the motor drive control device according to claim 1,
The control circuit unit
The actual rotation speed of the motor is calculated based on the position detection signal indicating the rotation position of the motor, and the correspondence information and calculation indicating the correspondence relationship between the rotation speed of the motor and the target current value stored in advance are calculated. A motor drive control device characterized in that the target current value is calculated based on the actual rotation speed. In the motor drive control device according to claim 2,
The motor rotates the impeller in the fan and
The corresponding relationship is a motor drive control device characterized in that the relationship between the rotational speed of the motor and the target current value in a region where the static pressure of the fan is lower than a predetermined value is shown. In the motor drive control device according to claim 2 or 3.
In the maximum air volume control, the control circuit unit generates the drive control signal so that the rotation speed of the motor increases when the current flowing through the motor is higher than the target current value, and the current flowing through the motor. A motor drive control device, characterized in that the drive control signal is generated so that the rotation speed of the motor decreases when is lower than the target current value. In the motor drive control device according to claim 4,
In the maximum air volume control, the control circuit unit increases the rotation speed of the motor when the current flowing through the motor is higher than a predetermined range based on the target current value, and the current flowing through the motor is determined by the predetermined range. When it is within the range, the rotation speed of the motor is not changed, and when the current flowing through the motor is lower than the predetermined range, the drive control signal is generated so as to reduce the rotation speed of the motor. A featured motor drive control device. The motor drive control device according to any one of claims 2 to 5.
The control circuit unit
A rotation speed calculation unit that calculates the actual rotation speed based on the position detection signal,
A speed control unit that generates a first control signal so that the actual rotation speed calculated by the rotation speed calculation unit matches the target rotation speed indicated by the speed command signal.
A target current value calculation unit that calculates the target current value based on the actual rotation speed calculated by the rotation speed calculation unit, and a target current value calculation unit.
A current value acquisition unit that acquires the current value of the current flowing through the motor,
A maximum air volume control unit that generates a second control signal so that the current flowing through the motor approaches the target current value when the target rotation speed is higher than the threshold value.
A motor drive control device including a drive control signal generation unit that generates the drive control signal based on the first control signal and the second control signal. With the motor
An impeller configured to be rotatable by the rotational force of the motor,
A motor drive control device for controlling the drive of the motor is provided.
The motor drive control device is
A control circuit unit that generates a drive control signal for controlling the rotation speed of the motor based on a speed command signal that indicates a target rotation speed of the motor.
It has a motor drive unit that drives the motor based on the drive control signal.
The control circuit unit
When the target rotation speed is lower than the threshold value, speed feedback control for generating the drive control signal is performed so that the rotation speed of the motor matches the target rotation speed, and when the target rotation speed is higher than the threshold value. A fan characterized in that the maximum air volume control for generating the drive control signal is performed so that the current flowing through the motor approaches the target current value calculated corresponding to the rotation speed of the motor. A motor drive control method in which a drive control signal for controlling the drive of the motor is generated based on a speed command signal indicating a target rotation speed of the motor, and the motor is driven based on the drive control signal. ,
The first step of generating the drive control signal so that the rotation speed of the motor matches the target rotation speed when the target rotation speed is lower than the threshold value.
The second step of generating the drive control signal so that the current flowing through the motor approaches the target current value calculated corresponding to the rotation speed of the motor when the target rotation speed is higher than the threshold value. A motor drive control method characterized by including.

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