Motor drive control device and fan unit

Abstract

To achieve motor output constant control by a simple configuration and calculation.SOLUTION: A motor drive control device 1 includes a control circuit 3 for outputting a drive control signal Sd for controlling drive of a motor 20 of a fan 22, and a motor drive circuit 2 for driving the motor 20 based on the drive control signal Sd. The control circuit 3 includes: a storage unit 31 that stores correspondence information 310_1 to 310_n indicating a relation between a value based on rotation speed of the motor 20 and torque when a motor output becomes constant at a predetermined value; a target torque determination unit 30 for determining a target torque Tg from the rotation speed by using the correspondence information 310 corresponding to a designated motor output; a target rotation speed determination unit 34 for determining target rotation speed EXC so that difference ΔT between the target torque Tg and a torque value Ts of the motor 20 becomes small; and a drive control signal generation unit 35 for generating the drive control signal Sd so that the rotation speed of the motor 20 approaches the target rotation speed EXC.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a motor drive control device and a fan unit. [Background technology]

[0002] Some motor drive control devices that drive motors for fans such as ventilation fans and dryers are known to have a constant air volume control function that controls the motor so that the air volume of the fan is constant even when the static pressure, etc. changes. For example, Patent Document 1 discloses a technology that keeps the air volume of the fan constant by correcting the rotation speed of the motor using a predetermined air volume value and a motor torque value. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5327045 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, there has been a demand for energy-saving and cost-saving fans such as ventilation fans and dryers. The inventors of the present application have considered that in order to realize energy-saving and cost-saving fans, it is essential to implement constant motor output control that controls the motor output (amount of work per unit time) of a motor to be constant. However, conventional constant motor output control techniques require complex configurations and calculations, and in order to achieve power savings and cost reductions in fans, it is necessary to achieve constant motor output control with simple configurations and calculations.

[0005] The present invention is intended to solve the above-mentioned problems, and has an object to realize constant motor output control with a simple configuration and calculation. [Means for solving the problem]

[0006] A motor drive control device according to a representative embodiment of the present invention comprises a control circuit that outputs a drive control signal for controlling the drive of a motor, and a motor drive circuit that drives the motor based on the drive control signal output from the control circuit, and the control circuit includes a memory unit that stores correspondence information indicating the relationship between a value based on the rotational speed of the motor and torque when the motor output of the motor becomes constant at a predetermined value, a target torque determination unit that determines a target torque value from a value based on the rotational speed of the motor using the correspondence information corresponding to the specified motor output, a torque acquisition unit that acquires a torque value of the motor, a target rotational speed determination unit that determines a target rotational speed of the motor, which is a speed that reduces the difference between the target torque value and the torque value acquired by the torque acquisition unit, and a drive control signal generation unit that generates the drive control signal based on the target rotational speed. Effect of the Invention

[0007] According to one aspect of the present invention, it is possible to realize constant motor output control with a simple configuration and calculation. [Brief description of the drawings]

[0008] [Figure 1] 1 is a diagram showing a configuration of a fan unit including a motor drive control device according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a diagram showing a functional block configuration of a control circuit. [Diagram 3] FIG. 11 is a diagram showing the relationship between the Hall period and the q-axis current (torque) of the motor. [Figure 4] 4 is a block diagram showing an internal configuration of a drive control signal generating unit. FIG. [Diagram 5] 4 is a flowchart showing a flow of processing for constant motor output control performed by the motor drive control device according to the present embodiment. [Figure 6] 5 is a diagram showing motor characteristics when constant motor output control is performed by the motor drive control device according to the embodiment of the present invention. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] 1. Overview of the embodiment First, a typical embodiment of the invention disclosed in this application will be outlined. In the following description, as an example, reference numerals in the drawings corresponding to components of the invention are given in parentheses.

[0010] [1] A motor drive control device (1) according to a representative embodiment of the present invention includes a control circuit (3) that outputs a drive control signal (Sd) for controlling the drive of a motor (20), and a motor drive circuit (2) that drives the motor based on the drive control signal output from the control circuit, and the control circuit includes a memory unit (31) that stores correspondence information (310, 310_1 to 310_n) indicating a relationship between a value based on the rotational speed of the motor and torque when the motor output of the motor becomes constant at a predetermined value, a target torque determination unit (30) that determines a target torque value (Tg) from a value based on the rotational speed of the motor using the correspondence information corresponding to a specified motor output, a torque acquisition unit (32) that acquires a torque value (Ts) of the motor, a target rotational speed determination unit (34) that determines a target rotational speed (EXC) of the motor, which is a speed that reduces a difference (ΔT) between the target torque value and the torque value acquired by the torque acquisition unit, and a drive control signal generation unit (35) that generates the drive control signal based on the target rotational speed.

[0011] [2] In the motor drive control device described in [1] above, the value based on the rotational speed of the motor may be a period (Hp) of a rotational position detection signal (Hu, Hv, Hw) whose voltage changes periodically depending on the rotational position of the rotor of the motor.

[0012] [3] In the motor drive control device described in [1] above, the value based on the rotational speed of the motor may be the reciprocal of the rotational speed of the motor.

[0013] [4] In the motor drive control device described in any one of [1] to [3] above, the torque acquisition unit may acquire a q-axis current value (Iq) corresponding to the torque of the motor as the torque value, and the target torque determination unit may determine a target value (Iq_g) of the q-axis current as the target torque value (Tg).

[0014] [5] In the motor drive control device described in [4] above, the motor has three-phase coils (Lu, Lv, Lw), and the drive control signal generation unit calculates the q-axis current and a d-axis current corresponding to the magnetic flux of the motor based on the current (Si) flowing through the coil of each phase of the motor, determines a duty ratio so that the calculated q-axis current and the d-axis current respectively match target current values ​​(Iq_req, Id_ref) corresponding to the target rotation speed, and outputs a PWM signal having that duty ratio as the drive control signal, and the torque acquisition unit may acquire the q-axis current calculated by the drive control signal generation unit as the torque value.

[0015] [6] In the motor drive control device described in any one of [1] to [5] above, the correspondence information may include functions (601 to 603) expressing the relationship between a value based on the rotational speed of the motor and torque, and the memory unit may store the functions for each of a plurality of specifiable command values ​​of the motor output.

[0016] [7] A fan unit (100) according to a representative embodiment of the present invention is characterized in that it comprises a motor drive control device (1) described in any one of [1] to [5] above, a motor (20) driven by the motor drive control device, and an impeller (21) configured to be rotatable by the rotational force of the motor.

[0017] 2. Specific examples of embodiments Hereinafter, specific examples of the embodiments of the present invention will be described with reference to the drawings. In the following description, components common to each embodiment will be given the same reference numerals, and repeated description will be omitted. It should be noted that the drawings are schematic, and the dimensional relationships and ratios of each element may differ from the actual situation. The drawings may also include parts with different dimensional relationships and ratios.

[0018] <Embodiment>

[0019] FIG. 1 is a diagram showing the configuration of a fan unit including a motor drive control device 1 according to the present embodiment.

[0020] 1 is a device that generates wind by rotating an impeller. The fan unit 100 can be applied to, for example, dryers, ventilation equipment (exhaust fans), and the like.

[0021] As shown in FIG. 1, the fan unit 100 includes a motor 20, an impeller 21, a rotational position detector 25 for detecting the rotational position of the motor 20, a rotational speed detector 26 for detecting the rotational speed of the motor 20, a current detector 27 for detecting the current flowing through the motor 20, and a motor drive control device 1 for driving the motor 20.

[0022] The motor 20 is, for example, a brushless motor. In this embodiment, the motor 20 is a brushless motor having three-phase coils. The motor drive control device 1 is a device for controlling the rotation of the motor 20. The motor drive control device 1, for example, outputs a sine wave drive signal to the motor 20 to periodically pass a sine wave drive current through the three-phase coils Lu, Lv, and Lw of the motor 20, thereby rotating the motor 20.

[0023] The impeller 21 is a component that generates wind, and is configured to be rotatable by the torque of the motor 20. For example, the rotation shaft of the impeller 21 is coaxially connected to the output shaft of the motor 20. In this embodiment, for example, the impeller 21 and the motor 20 constitute one fan 22.

[0024] The motor drive control device 1 has a motor drive circuit 2 and a control circuit 3. Note that the components of the motor drive control device 1 shown in Fig. 1 are only a part of the whole, and the motor drive control device 1 may have other components in addition to those shown in Fig. 1.

[0025] The motor drive circuit 2 drives the motor 20 based on a drive control signal Sd output from a control circuit 3, which will be described later. The motor drive circuit 2 has an inverter circuit 2a and a pre-drive circuit 2b.

[0026] The inverter circuit 2a outputs a drive signal to the motor 20 based on the output signal output from the pre-drive circuit 2b, and energizes the coils Lu, Lv, and Lw of the motor 20. The inverter circuit 2a is configured, for example, by arranging a pair of two switch elements connected in series between a DC power supply Vcc and a ground potential for each phase (U phase, V phase, and 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.

[0027] The pre-drive circuit 2b generates an output signal for driving the inverter circuit 2a based on a drive control signal Sd from the control circuit 3, and outputs the output signal to the inverter circuit 2a.

[0028] The drive control signal Sd is a signal for controlling the drive of the motor 20, and is, for example, a PWM (Pulse Width Modulation) signal. Specifically, the drive control signal Sd includes six types of PWM signals corresponding to each switch element of the inverter circuit 2a. More specifically, the drive control signal Sd is a signal for switching on / off each switch element constituting the inverter circuit 2a.

[0029] The pre-drive circuit 2b generates and outputs six types of drive signals Vuu, Vul, Vvu, Vvl, Vwu, and Vwl that drive the respective switch elements of the inverter circuit 2a based on, for example, the drive control signal Sd. By inputting these drive signals to the inverter circuit 2a, the switch elements that constitute the inverter circuit 2a and correspond to the respective drive signals perform on / off operations. By controlling the on / off of each switch element of the inverter circuit 2a, the current conduction pattern of the coils Lu, Lv, and Lw of the motor 20 is switched, and power is supplied to each phase of the motor 20.

[0030] The rotational position detectors 25u, 25v, and 25w generate signals corresponding to the rotational position of the rotor of the motor 20. The rotational position detectors 25u, 25v, and 25w are, for example, Hall elements. Hereinafter, the rotational position detectors 25u, 25v, and 25w are also referred to as "Hall elements 25u, 25v, and 25w."

[0031] The three Hall elements 25u, 25v, and 25w are provided corresponding to the respective phases (U phase, V phase, and W phase) of the motor 20. The Hall elements 25u, 25v, and 25w are arranged around the rotor of the motor 20 at approximately equal intervals (for example, at intervals of 120 degrees from adjacent elements).

[0032] The Hall elements 25u, 25v, and 25w each detect the magnetic pole of the rotor of the motor 20 and output a Hall signal whose voltage changes periodically according to the rotational position of the rotor. Hereinafter, the Hall signals output from the Hall elements 25u, 25v, and 25w, respectively, are also referred to as "rotational position detection signals Hu, Hv, and Hw."

[0033] The rotational position detection signals Hu, Hv, and Hw are input to the control circuit 3. Note that the control circuit 3 may be configured so that, instead of such a Hall signal, another signal corresponding to the rotational position of the rotor of the motor 20 is input as the rotational position detection signal. For example, an encoder, resolver, motor current detection circuit, or the like may be provided, and the detection signal thereof may be input to the control circuit 3. In other words, the rotational position detectors 25u, 25v, and 25w are not limited to Hall elements.

[0034] The rotation speed detector 26 generates a rotation speed signal Sr corresponding to the rotation of the rotor of the motor 20. The rotation speed detector 26 is, for example, an FG (Frequency Generator) pattern formed on a board (printed board) on which the motor 20 is mounted. The FG pattern as the rotation speed detector 26 generates a signal (FG signal) having a period corresponding to the rotation speed of the motor 20. The FG signal output from the rotation speed detector 26 is input to the control circuit 3 as the rotation speed signal Sr.

[0035] In this embodiment, an FG pattern is used as the rotation speed detector 26, but this is not limiting, and other rotation speed detectors such as an encoder or resolver may be used. Alternatively, the rotation speed detector 26 may derive the rotation speed based on the Hall signals (rotation position detection signals Hu, Hv, Hw) and input it to the control circuit 3 as the rotation speed signal Sr, or the control circuit 3 may calculate the rotation speed based on the Hall signals.

[0036] The current detector 27 generates a current detection signal Si corresponding to the current value of the current flowing through the DC side of the inverter circuit 2a constituting the motor drive circuit 2. The current detector 27 is, for example, a current detection element disposed on the negative side (ground side) of the inverter circuit, such as a resistor (shunt resistor). The current detection element as the current detector 27 generates a voltage corresponding to the current flowing through it, and outputs it as the current detection signal Si.

[0037] The control circuit 3 generates a drive control signal Sd for driving the motor 20 based on an output command signal Sf that specifies the magnitude of the motor output, and supplies the signal to the motor drive circuit 2. Specifically, the control circuit 3 monitors the rotation state of the motor 20 by obtaining information such as the rotational position and rotational speed of the rotor of the motor 20 based on the rotational position detection signals Hu, Hv, Hw and the rotational speed signal Sr, and generates a drive control signal Sd to control the drive of the motor 20 so that the motor output of the motor 20 becomes the value specified by the output command signal Sf.

[0038] In this embodiment, the control circuit 3 is realized by a program processing device (e.g., a microcontroller) having a configuration in which a processor such as a CPU, various storage devices such as RAM and ROM, and peripheral circuits such as a counter (timer), an A / D conversion circuit, a D / A conversion circuit, a clock generation circuit, and an input / output I / F circuit are connected to each other via a bus or a dedicated line.

[0039] The motor drive control device 1 may be configured such that at least a part of the control circuit 3 and at least a part of the motor drive circuit 2 are packaged as a single integrated circuit device (IC), or the control circuit 3 and the motor drive circuit 2 are each packaged as separate integrated circuit devices.

[0040] When controlling the fan 22 based on the output command signal Sf, the control circuit 3 performs constant motor output control to generate a drive control signal Sd so as to maintain constant motor output of the motor 20. The constant motor output control performed by the control circuit 3 will now be described.

[0041] FIG. 2 is a diagram showing a functional block configuration of the control circuit 3. 2, the control circuit 3 has, as functional blocks for realizing constant motor output control, a target torque determination unit 30, a storage unit 31, a torque acquisition unit 32, an error calculation unit 33, a target rotation speed determination unit 34, and a drive control signal generation unit 35. These functional blocks are realized, for example, in a program processing device serving as the control circuit 3, by a processor executing various arithmetic processing according to a program stored in a memory and controlling peripheral circuits such as a counter and an A / D conversion circuit. Note that some or all of the functional blocks constituting the control circuit 3 may be realized by dedicated hardware circuits.

[0042] The target torque determination unit 30 is a functional unit that determines a target value of the torque of the motor 20 (hereinafter referred to as the "target torque value") required for the motor output (work volume per unit time) of the motor 20 to become a value specified by the output command signal Sf. Although details will be described later, the target torque determination unit 30 calculates the target torque value Tg from a value based on the rotation speed of the motor using correspondence information 310 that indicates the relationship between the value based on the rotation speed of the motor and the torque.

[0043] The storage unit 31 is a functional unit that stores parameters and the like required for constant motor output control. The storage unit 31 stores, for example, correspondence information 310 and data such as an initial value of a target rotation speed EXC set for each command value of the motor output.

[0044] As described above, the correspondence information 310 is data indicating the relationship between the torque and a value based on the rotation speed of the motor 20 when the motor output of the motor 20 becomes constant at a predetermined value.

[0045] Here, the value based on the rotation speed of the motor 20 is, for example, the period of the rotation position detection signals Hu, Hv, Hw, or the reciprocal of the rotation speed [rpm].

[0046] In this embodiment, as an example, the value based on the rotation speed of the motor 20 is the period of any one of the rotational position detection signals Hu, Hv, and Hw, and this period is referred to as the "Hall period Hp."

[0047] It is generally known that the torque of a motor is proportional to the current of the q-axis in a two-axis (q-axis, d-axis) rotating coordinate system in vector control of the motor. Therefore, in this embodiment, as an example, the q-axis current Iq is used as a physical quantity that represents the torque of the motor.

[0048] Generally, motor output, that is, the amount of work per unit time P [W], is expressed by the following formula (1), where T is the torque [N·m] and N is the rotational speed [rpm].

[0049]

number

[0050] As described above, in the vector control of the motor, the q-axis current Iq and the motor torque T are in a proportional relationship, so the following equation (2) holds true, where α is a constant.

[0051]

number

[0052] In addition, since the motor rotation speed N is inversely proportional to the Hall period Hp [s], the following formula (3) holds true, where β is a constant.

[0053]

number

[0054] From the above equations (1) to (3), the following equation (4) holds for the q-axis current Iq.

[0055]

number

[0056] As can be seen from the above formula (4), when the motor output P is constant, the relationship between the q-axis current Iq (torque) and the Hall period Hp can be expressed by a linear equation.

[0057] FIG. 3 is a diagram showing the relationship between the Hall period and the q-axis current (torque) of the motor. 3, the horizontal axis represents the Hall period Hp, and the vertical axis represents the q-axis current Iq as the torque of the motor 20. In FIG.

[0058] Each graph indicated by reference numerals 601 to 603 is a Hall period-torque characteristic showing the relationship between the actual measured value of the Hall period Hp and the actual measured value of the q-axis current Iq (torque) of the motor 20 when the motor 20 is operated so that the motor output of the motor 20 is constant at a predetermined value. Specifically, reference numeral 601 represents the characteristic of the q-axis current Iq (torque) of the motor 20 with respect to the Hall period Hp when the motor output of the motor 20 is a first value (W1=5W (watts)). Reference numeral 602 represents the characteristic of the q-axis current Iq of the motor 20 with respect to the Hall period Hp when the motor output of the motor 20 is a second value (W2=10W). Reference numeral 603 represents the characteristic of the q-axis current of the motor 20 with respect to the Hall period Hp when the motor output of the motor 20 is a third value (W3=15W).

[0059] 3, it can be seen that the Hall period-torque characteristics of the motor based on the actual measurement results can be approximated by a linear equation as shown in the above-mentioned equation (4). Therefore, by controlling the Hall period (rotation speed) and the q-axis current of the motor 20 to change along the characteristics 601 to 603 according to the motor output required for the motor 20, it is possible to operate the motor 20 so that the motor output is constant at the required value.

[0060] Therefore, the motor drive control device 1 of this embodiment pre-stores in the memory unit 31 a correspondence relationship 310 that represents the relationship between a value based on the rotational speed of the motor 20 for each motor output (Hall period Hp) and torque (q-axis current Iq), and uses this correspondence relationship 310 to adjust the rotational speed and torque of the motor 20, thereby keeping the motor output of the motor 20 constant.

[0061] Specifically, functions corresponding to a plurality of motor output command values ​​that can be specified for the motor 20 are stored in the storage unit 31 as the correspondence relationship 310. For example, in the case where the motor output level of the motor 20 can be switched between n levels (n is an integer equal to or greater than 2), functions that express the relationship between the Hall period Hp and the q-axis current Iq for each of the n motor output command values ​​are stored in the storage unit 31 as the correspondence relationships 310_1 to 310_n.

[0062] For example, as shown in FIG. 3, the Hall period and the q-axis current (torque) of the motor 20 are measured in advance by experiments, simulations, etc. when the motor 20 is driven so that the motor output of the motor 20 is constant at a predetermined value. Next, an approximation function (e.g., a linear function) showing the relationship between the Hall period and the q-axis current is calculated for each motor output by performing a regression analysis using the measured values ​​of the Hall period and the q-axis current. Then, for example, information showing these approximation functions (e.g., coefficients of the linear function) is stored in the storage unit 31 of the motor drive control device 1 as correspondence information 310_1 to 310_n. Hereinafter, the correspondence information 310_1 to 310_n will also be referred to as "functions 310_1 to 310_n."

[0063] For example, consider a case where the fan unit 100 is applied to a hair dryer and the motor output of the hair dryer (motor 20) can be set to three levels (n=3), namely, "weak (5W)", "medium (10W)", and "strong (15W)". In this case, the coefficient of an approximation function expressing the relationship between the measured value of the Hall period and the measured value of the q-axis current when the motor output is constant at "weak (5W)" is stored in the storage unit 31 as correspondence information 310_1. Similarly, the coefficient of an approximation function expressing the relationship between the measured value of the Hall period and the measured value of the q-axis current when the motor output is constant at "medium (10W)" is stored in the storage unit 31 as correspondence information 310_2, and the coefficient of an approximation function expressing the relationship between the measured value of the Hall period and the measured value of the q-axis current when the motor output is constant at "strong (15W)" is stored in the storage unit 31 as correspondence information 310_3.

[0064] The target torque determination unit 30 calculates a target torque value Tg based on the output command signal Sf, a value based on the rotation speed of the motor 20, and functions 310_1 to 310_n stored in the storage unit 31. Specifically, as shown in FIG. 2, the target torque determination unit 30 has an output command acquisition unit 36, a function selection unit 37, and a target torque calculation unit 38.

[0065] The output command acquisition unit 36 ​​is a functional unit that acquires a command value of the motor output from an output command signal Sf input from outside. For example, when a user operates the operation input unit of the fan 22 to specify a desired output, the operation input unit generates an output command signal Sf indicating the specified output and inputs it to the output command acquisition unit 36.

[0066] The output command acquisition unit 36 ​​acquires a command value of the motor output from the input output command signal Sf. For example, consider a case where the motor output of the dryer (motor 20) can be set to three levels, namely, "weak", "medium", and "strong", as described above, and the output command signal Sf is a two-bit digital signal. In this case, the output command acquisition unit 36 ​​determines whether the command value of the motor output is "weak", "medium", "strong", or "stop operation" based on the two-bit logical value of the output command signal Sf. For example, the output command acquisition unit 36 ​​determines that the output command signal Sf is an instruction to stop the dryer (motor 20) when the output command signal Sf is "00", determines that the command value of the motor output of the dryer is "weak" when the output command signal Sf is "01", determines that the command value of the motor output of the dryer is "medium" when the output command signal Sf is "10", and determines that the command value of the motor output of the dryer is "strong" when the output command signal Sf is "11".

[0067] The function selection unit 37 selects one of the functions 310_1 to 310_n based on the motor output command value acquired by the output command acquisition unit 36. The function selection unit 37 selects the functions 310_1 to 310_n corresponding to the motor output of the motor 20 specified by the motor output command value acquired by the output command acquisition unit 36, and reads out the selected function from the storage unit 31.

[0068] The target torque calculation unit 38 uses the function 310 selected by the function selection unit 37 to calculate the target torque value Tg from a value based on the rotation speed of the motor 20 .

[0069] First, the target torque calculation unit 38 calculates a value based on the rotation speed of the motor 20. For example, the target torque calculation unit 38 calculates a Hall period Hp as a value based on the rotation speed based on the rotation position detection signals Hu, Hv, and Hw. Specifically, the target torque calculation unit 38 calculates the period of any one of the rotation position detection signals Hu, Hv, and Hw, and sets it as the Hall period Hp.

[0070] The method of calculating the Hall period Hp is not limited to the above-mentioned method. For example, the target torque calculation unit 38 may calculate the average value of the periods of the three rotational position detection signals Hu, Hv, and Hw to obtain the Hall period Hp, or may synthesize the three rotational position detection signals Hu, Hv, and Hw by a known method to generate a three-phase synthetic signal, and calculate the Hall period Hp based on the period of the three-phase synthetic signal.

[0071] Next, the target torque calculation unit 38 calculates a target torque value Tg of the motor 20 based on the calculated Hall period Hp and the function 310 selected by the function selection unit 37. For example, the target torque calculation unit 38 calculates a target value Iq_g of the q-axis current by substituting the value of the Hall period Hp calculated based on the rotational position detection signals Hu, Hv, and Hw into a variable (Hall period) in the function 310, and outputs the calculated target value Iq_g of the q-axis current as the target torque value Tg.

[0072] The torque obtaining unit 32 is a functional unit that obtains a measured value of the torque of the motor 20. For example, the torque obtaining unit 32 obtains a q-axis current Iq calculated in a calculation process of vector control performed in a drive control signal generating unit 35, which will be described later. The torque obtaining unit 32 calculates a torque value Ts based on the q-axis current Iq calculated in the drive control signal generating unit 35. For example, the torque obtaining unit 32 outputs the q-axis current Iq calculated in the drive control signal generating unit 35 as the torque value Ts.

[0073] The method of calculating the torque value Ts by the torque obtaining unit 32 is not limited to the above-mentioned method. For example, the torque obtaining unit 32 may calculate an average value of the q-axis current Iq for each predetermined period and output the calculated value as the torque value Ts, or may multiply the q-axis current Iq or the average value of the q-axis current Iq for each predetermined period by a predetermined coefficient and output the result as the torque value Ts. When the torque obtaining unit 32 converts the q-axis current Iq into torque, for example, the target torque calculating unit 38 may multiply the target value Iq_g of the q-axis current calculated using the correspondence information 310 by a predetermined coefficient to calculate the torque value Ts, or the correspondence information 310 may be a function indicating the relationship between the value obtained by converting the q-axis current into torque and the Hall period Hp.

[0074] The error calculation unit 33 is a functional unit that calculates the difference between the target torque value Tg determined by the target torque determination unit 30 and the torque value Ts, which is the measured value of the torque of the motor 20 acquired by the torque acquisition unit 32. The error calculation unit 33 outputs the difference between the target torque value Tg and the torque value Ts as a torque error ΔT.

[0075] The target rotation speed determination unit 34 is a functional unit that determines the target rotation speed EXC of the motor 20 so as to reduce the difference between the target torque value Tg and the torque value Ts. As shown in FIG. 2, the target rotation speed determination unit 34 has a PI control calculation unit 40 and a target rotation speed calculation unit 41. The PI control calculation unit 40 calculates a control amount by a PI control calculation so that the torque error ΔT becomes zero. That is, the target rotation speed calculation unit 41 determines the target rotation speed EXC of the motor 20, which is a speed that reduces the difference between the target torque value Tg and the torque value Ts acquired by the torque acquisition unit 32. The target rotation speed calculation unit 41 calculates the target rotation speed EXC, for example, by multiplying the control amount calculated by the PI control calculation unit 40 by a predetermined conversion coefficient.

[0076] For example, in a fan, generally, when the rotation speed of the motor is increased, the air resistance increases and the load (torque) increases, and conversely, when the rotation speed of the motor is decreased, the air resistance decreases and the load decreases. In other words, in a fan, the torque error ΔT can be controlled to be 0 by controlling the rotation speed of the motor. In this case, when the output signal of the PI control calculation unit 40 is a 10-bit digital value, the output signal becomes a signal of the manipulated variable expressed by 0 to 1023. Therefore, the target rotation speed determination unit 34 converts the manipulated variable output from the PI control calculation unit 40 into the target rotation speed EXC by multiplying the output signal (digital value) of the PI control calculation unit 40 by a predetermined conversion coefficient.

[0077] In addition, the target rotation speed determination unit 34 may calculate the target rotation speed EXC from the output signal of the PI control calculation unit 40 by performing Q formatting (fixed point) or saturation processing of upper and lower limits, rather than multiplying the output signal of the PI control calculation unit 40 by a predetermined conversion coefficient.

[0078] When the target rotation speed determination unit 34 and the drive control signal generation unit 35 are realized by different integrated circuit devices (ICs), the target rotation speed determination unit 34 may generate, for example, a periodic signal having a frequency corresponding to the target rotation speed EXC. In this case, the periodic signal is output from an external terminal of the integrated circuit device in which the target rotation speed determination unit 34 is formed, and input to an external terminal of the integrated circuit device in which the drive control signal generation unit 35 is formed. The drive control signal generation unit 35 acquires information on the target rotation speed EXC by analyzing the frequency of the input periodic signal.

[0079] The drive control signal generating unit 35 is a functional unit that generates a drive control signal Sd so that the rotation speed of the motor 20 approaches the target rotation speed EXC. The drive control signal generating unit 35 generates the drive control signal Sd as a PWM signal, for example, by a so-called vector control calculation. Note that the method of generating the drive control signal Sd by the drive control signal generating unit 35 is not limited to the above-mentioned vector control calculation, and may be calculation based on a known motor drive control technique such as vf control or advance angle control. In this embodiment, however, the drive control signal generating unit 35 is described as generating the drive control signal Sd by a vector control calculation.

[0080] As a vector control calculation, the drive control signal generating unit 35 calculates a q-axis current Iq corresponding to the torque of the motor 20 and a d-axis current Id corresponding to the magnetic flux of the motor 20 based on the current flowing through the coils of each phase of the motor 20, determines a duty ratio so that the calculated q-axis current Iq and d-axis current Id respectively match the target current values ​​Iq_ref, Id_ref corresponding to the target rotation speed EXC, and outputs a PWM signal having that duty ratio as a drive control signal Sd.

[0081] In this embodiment, a case will be described in which the drive control signal generating unit 35 performs vector control calculation using the rotational position detection signals Hu, Hv, Hw output from the Hall elements. However, this is not limited to this, and the drive control signal generating unit 35 may perform so-called sensorless vector control calculation that does not use the rotational position detection signals Hu, Hv, Hw.

[0082] FIG. 4 is a block diagram showing the internal configuration of the drive control signal generating unit 35. As shown in FIG. The drive control signal generating unit 35 has functional blocks for functioning as a vector control unit, including a current measurement unit 50, a Clarke conversion unit 51, a Park conversion unit 52, a rotation information generating unit 56, a rotational speed PI control unit 60, a flux-weakening PI control unit 61, a torque PI control unit 62, a flux PI control unit 63, an inverse Park conversion unit 64, an inverse Clarke conversion unit 65, and a PWM signal generating unit 66. These functional blocks are realized by a processor executing various arithmetic processes according to programs stored in a memory in a program processing device constituting the control circuit 3, and controlling peripheral circuits such as a counter and an A / D conversion circuit. Note that some or all of these functional blocks may be realized by dedicated hardware circuits.

[0083] The current measurement unit 50 acquires the current detection signal Si output from the current detector 27, and generates measurement values ​​of the phase currents Iu, Iv, and Iw of each phase of the motor 20 based on the acquired current detection signal Si. The Clarke transformation unit 51 performs Clarke transformation on the measurement values ​​of the phase currents Iu, Iv, and Iw generated by the current measurement unit 50 to calculate currents Iα and Iβ in a two-phase orthogonal coordinate (fixed coordinate) system (α, β). The Park transformation unit 52 performs Park transformation on the currents Iα and Iβ using the electrical angle θ (sin θ and cos θ) calculated by the electrical angle calculation unit 54 to calculate the q-axis current Iq and the d-axis current Id of the rotating coordinates from the currents Iα and Iβ in the two-phase fixed coordinates.

[0084] Here, the q-axis current Iq is a current corresponding to the torque of the motor 20 (torque current), and the d-axis current Id is an excitation current of the motor 20.

[0085] The rotation information generating unit 56 is a functional unit that generates information (rotation information) related to the rotation state of the motor 20. The rotation information generating unit 56 calculates, as the rotation information of the motor 20, the rotation angles θ, sin θ, and cos θ of the rotor of the motor 20, and the rotation speed (actual rotation speed) of the motor 20.

[0086] The rotation information generating unit 56 includes, for example, a rotation position detection signal acquiring unit 53, an electrical angle calculating unit 54, and a rotation speed signal acquiring unit 55. The rotation position detection signal acquiring unit 53 acquires the rotation position detection signals (Hall signals) Hu, Hv, and Hw output from the rotation position detectors 25u, 25v, and 25w. The electrical angle calculating unit 54 calculates the rotation angle θ of the rotor of the motor 20 and calculates sin θ and cos θ by a known calculation method based on the three rotation position detection signals Hu, Hv, and Hw acquired by the rotation position detection signal acquiring unit 53. The rotation speed signal acquiring unit 55 acquires the rotation speed signal (FG signal) Sr output from the rotation speed detector 26, and acquires a measurement value of the rotation speed of the motor 20 based on the acquired rotation speed signal Sr.

[0087] In addition, when the drive control signal generating unit 35 performs the above-mentioned sensorless vector control, the rotation information generating unit 56 may calculate the rotor's rotational angles θ, sin θ, cos θ, and rotational speed (ω) by known sensorless vector control calculations.

[0088] The rotation speed PI control unit 60 performs a PI control calculation based on the target rotation speed EXC of the motor 20 output from the target rotation speed determination unit 34 and the measurement value of the rotation speed of the motor 20 acquired by the rotation speed signal acquisition unit 55. The rotation speed PI control unit 60 calculates the difference between the target rotation speed EXC and the measurement value of the rotation speed of the motor 20, and calculates a control amount by the PI control calculation so as to reduce the difference.

[0089] The flux-weakening PI control unit 61 calculates, by a known calculation method, a q-axis current target value Iq_ref, which is the target value of the torque current, and a d-axis current target value Id_ref, which is the target value of the excitation current, based on the voltage command values ​​Vq, Vd described later and the control amount calculated by the rotational speed PI control unit 60.

[0090] The torque PI control unit 62 performs a PI control calculation based on the q-axis current target value Iq_ref calculated by the flux-weakening PI control unit 61 and the q-axis current Iq calculated by the park conversion unit 52. The torque PI control unit 62 calculates the difference between the q-axis current target value Iq_ref and the q-axis current Iq, and calculates a voltage command value Vq as a control amount for reducing the difference by a PI control calculation. The flux PI control unit 63 calculates the difference between the d-axis current target value Id_ref and the d-axis current Id, and calculates a voltage command value Vd as a control amount for reducing the difference by a PI control calculation.

[0091] The inverse Park transformation unit 64 calculates voltages Vα, Vβ of two-phase fixed coordinates from the rotating coordinates by performing an inverse Park transformation on the voltage command values ​​Vq, Vd using the electrical angle θ (sin θ and cos θ) calculated by the electrical angle calculation unit 54. The inverse Clarke transformation unit 65 calculates three-phase voltages Vu, Vv, Vw by performing an inverse Clarke transformation on the voltages Vα, Vβ of the two-phase fixed coordinates.

[0092] The PWM signal generating unit 66 calculates duty ratios (set values ​​of the duty ratios of each phase) Udu, Vdu, and Wdu for generating three-phase PWM signals by a known calculation method based on the phase voltages Vu, Vv, and Vw of each phase calculated by the inverse Clarke transform unit 65. The PWM signal generating unit 66 generates three-phase PWM signals having the calculated duty ratios of each phase, and outputs them as the drive control signal Sd.

[0093] Next, a process flow of constant motor output control performed by the motor drive control device 1 according to this embodiment will be described.

[0094] FIG. 5 is a flowchart showing the flow of processing for constant motor output control by the motor drive control device 1 according to this embodiment.

[0095] For example, consider a case where a user operates an operation input unit of fan 22 (e.g., a hair dryer) to instruct fan 22 to operate at a predetermined output while the operation of fan 22 is stopped. In this case, the operation input unit of fan 22 inputs an output command signal Sf including a command value for the motor output to motor drive control device 1 in response to the user's operation (step S1).

[0096] When the output command signal Sf is input, the motor drive control device 1 starts drive control of the motor 20 (step S2). Specifically, in the motor drive control device 1, for example, the target torque determination unit 30 reads out an initial value of the target rotation speed EXC corresponding to the command value of the motor output specified by the output command signal Sf from the storage unit 31 and sets it in the target rotation speed determination unit 34, and the target rotation speed determination unit 34 inputs the set initial value of the target rotation speed EXC to the drive control signal generation unit 35. The drive control signal generation unit 35 performs the above-mentioned vector control calculation based on the initial value of the target rotation speed EXC input from the target rotation speed determination unit 34 to generate the drive control signal Sd and inputs it to the motor drive circuit 2. As a result, the motor 20 starts rotating.

[0097] Next, the target torque determination unit 30 selects the function 310 corresponding to the command value of the motor output specified in step S1 (step S3). Specifically, as described above, the function selection unit 37 reads out the function 310 corresponding to the command value of the motor output specified by the output command signal Sf from the storage unit 31, and provides it to the target torque calculation unit 38.

[0098] The target torque calculation unit 38 acquires the Hall period Hp (step S4). For example, as described above, the target torque calculation unit 38 acquires the period of at least one of the rotational position detection signals Hu, Hv, and Hw as the Hall period Hp.

[0099] Next, the target torque calculation unit 38 calculates the target torque value Tg (target value Iq_g of the q-axis current) from the Hall period Hp calculated in step S4 using the function 310 read in step S3 by the method described above (step S5).

[0100] Furthermore, in the motor drive control device 1, the torque obtaining unit 32 calculates the torque of the motor 20 (step S6). Specifically, as described above, the torque obtaining unit 32 obtains the q-axis current Iq calculated by the vector control calculation by the drive control signal generating unit 35, and calculates the torque value Ts (measured torque value) of the motor 20 based on the q-axis current Iq.

[0101] Next, in the motor drive control device 1, the error calculation unit 33 calculates a torque error ΔT, which is the difference between the target torque value Tg (target value Iq_g of the q-axis current) calculated in step S4 and the torque value Ts (q-axis current Iq) calculated in step S6 (step S7).

[0102] Next, in the motor drive control device 1, the target rotation speed determination unit 34 calculates the target rotation speed EXC from the torque error ΔT calculated in step S7 by the above-mentioned method (step S8). As a result, the value of the target rotation speed EXC is updated based on the torque error ΔT that reflects the actual driving state of the motor 20.

[0103] Next, in the motor drive control device 1, the drive control signal generating unit 35 determines the duty ratio of the PWM signal as the drive control signal Sd based on the target rotation speed EXC updated in step S8, generates a drive control signal Sd having the determined duty ratio, and provides it to the motor drive circuit 2 (step S9). As a result, the rotation speed of the motor 20 is adjusted to the target rotation speed EXC, and the torque of the motor 20 is adjusted to the target torque value Tg. That is, the Hall period Hp according to the rotation of the motor 20 and the torque of the motor 20 are controlled to conform to the Hall period-torque characteristics shown in Fig. 3, so that the motor 20 operates so that the motor output of the motor 20 (fan 22) is constant at the value specified in step S1.

[0104] Thereafter, the motor drive control device 1 determines whether the designated value of the motor output has been changed (step S10). If the motor output command value has been changed by the new output command signal Sf (step S10: Yes), the motor drive control device 1 proceeds to step S3 and executes the above-mentioned processes (S3 to S9) to read out the function 310 according to the new motor output command value, update the target torque value Tg (target value Iq_g of the q-axis current), and generate a drive control signal Sd based on the recalculated target rotation speed EXC to control the rotation of the motor 20. As a result, the fan 22 operates at the newly designated constant motor output.

[0105] On the other hand, if the command value of the motor output has not been changed (step S10: No), the motor drive control device 1 determines whether or not an instruction to stop the operation of the fan 22 has been issued (step S11). If the output command signal Sf has not instructed the fan 22 to stop operating (step S11: No), the motor drive control device 1 proceeds to step S5, executes the above-mentioned processes (S6 to S9), and generates a drive control signal Sd so that the fan 22 continues to operate at the motor output specified in step S1.

[0106] On the other hand, when an instruction to stop the operation of the fan 22 is given (step S11: Yes), the motor drive control device 1 stops the rotation of the motor 20 by the drive control signal Sd. For example, the target torque determination unit 30 (e.g., the output command acquisition unit 36) instructs the target rotation speed determination unit 34 (e.g., the target rotation speed calculation unit 41) to set the target rotation speed EXC to zero. This stops the rotation of the motor 20, and the fan 22 stops.

[0107] FIG. 6 is a diagram showing the characteristics of motor 20 when motor drive control device 1 performs constant motor output control.

[0108] In FIG. 6, the horizontal axis represents the torque [mN·m] of the motor 20, the left side of the vertical axis represents the rotation speed [rpm] of the motor 20, and the right side of the vertical axis represents the motor output [W]. Reference numeral 701 indicates the change (actual measurement value) of motor output relative to the torque of the motor 20 when the motor output is kept constant at 5 W, and reference numeral 801 indicates the change (actual measurement value) of rotation speed relative to the torque of the motor 20 when the motor output is kept constant at 5 W. Reference numeral 702 indicates the change (actual measurement value) of motor output relative to the torque of the motor 20 when the motor output is kept constant at 10 W, and reference numeral 802 indicates the change (actual measurement value) of rotation speed relative to the torque of the motor 20 when the motor output is kept constant at 10 W. Reference numeral 703 indicates the change (actual measurement value) of motor output relative to the torque of the motor 20 when the motor output is kept constant at 15 W, and reference numeral 803 indicates the change (actual measurement value) of rotation speed relative to the torque of the motor 20 when the motor output is kept constant at 15 W.

[0109] As shown in FIG. 6, it can be seen that, according to the motor drive control device 1 of the present embodiment, the rotation speed (Hall period Hp) is controlled in response to changes in the torque of the motor 20, thereby making the motor output constant.

[0110] As described above, the motor drive control device 1 according to this embodiment stores in advance in the storage unit 31 correspondence information (Hall period-torque characteristics) 310_1 to 310_n indicating the relationship between a value (e.g., Hall period Hp) based on the rotational speed of the motor 20 when the motor output of the motor 20 becomes constant at a predetermined value and torque. The motor drive control device 1 calculates a target torque value Tg from a value based on the rotational speed of the motor 20 using the correspondence information 310 according to a specified motor output command value. The motor drive control device 1 determines a target rotational speed EXC of the motor so that the difference between the calculated target torque value and the measured torque value of the motor 20 becomes small, and generates a drive control signal Sd based on the target rotational speed EXC to drive the motor 20.

[0111] According to this, the motor drive control device 1 determines the target rotational speed EXC of the motor 20 according to the relationship between the torque and a value based on the rotational speed of the motor 20 at a specified motor output value, so that the motor 20 can be rotated so that the motor output is constant.

[0112] Furthermore, the motor drive control device 1 pre-stores in the storage unit 31 the relationship between the torque and a value based on the rotation speed of the motor 20 at a specified motor output as correspondence information 310, and calculates the target torque value from the value based on the rotation speed using that correspondence information 310, so no complex calculation is required to calculate the target torque value. This makes it possible to reduce the processing load on the microcontroller and other components of the control circuit 3.

[0113] Therefore, the motor drive control device 1 according to this embodiment makes it possible to control the motor output to be constant by using a simple configuration and calculations. That is, it becomes possible to realize constant motor output control by using a cheaper microcontroller instead of an expensive microcontroller capable of performing complex calculations at high speed.

[0114] In the motor drive control device 1, the correspondence information 310 includes a function that represents the relationship between a value based on the rotation speed of the motor 20 and the torque, and the memory unit 31 stores functions 310_1 to 310_n for each of a plurality of motor output command values ​​that can be specified for the fan 22.

[0115] According to this, even if multiple motor outputs are selectable for fan 22, by appropriately selecting one of functions 310_1 to 310_n of value-torque characteristics based on rotation speed in accordance with the specified motor output, it becomes easy to control motor 20 so that the motor output is constant at a specified value.

[0116] In the motor drive control device 1, a value based on the rotation speed of the motor 20 is the period (Hall period Hp) of the rotational position detection signals Hu, Hv, Hw whose voltages change periodically according to the rotational position of the rotor of the motor 20.

[0117] This makes it even easier to calculate the target torque value Tg, as will be described below. If the rotation speed itself were used as a value based on the rotation speed of the motor 20, the torque (target torque value) and the rotation speed would be inversely proportional, and a "division" would be required to calculate the target torque value from the rotation speed, increasing the processing load on the microcontroller serving as the control circuit 3. In contrast, if the Hall period Hp is used as a value based on the rotation speed of the motor 20, the torque (target torque value) and the Hall period Hp are in a proportional relationship (see equation (4)), and therefore the control circuit 3 only needs to perform "multiplication" to calculate the target torque value from the Hall period Hp. This makes it possible to reduce the processing load on the control circuit 3 and to use a less expensive microcontroller as the control circuit 3.

[0118] Moreover, the motor drive control device 1 acquires the q-axis current Iq calculated by so-called vector control calculation as the torque value Ts of the motor 20, and calculates a target value Iq_g of the q-axis current as the target torque value Tg.

[0119] This eliminates the need for torque acquisition unit 32 to perform complex arithmetic processing to calculate torque value Ts of motor 20, making it possible to achieve constant motor output control with a simpler and less expensive configuration. For example, consider a case in which drive control signal generation unit (vector control unit) 35 in motor drive control device 1 is realized by an existing integrated circuit device (IC) for vector control calculation, and target torque determination unit 30, storage unit 31, torque acquisition unit 32, and target rotational speed determination unit 34 in motor drive control device 1 are realized by integrated circuit devices different from the integrated circuit device for vector control calculation.

[0120] In this case, the integrated circuit device for realizing the target torque determination unit 30, the storage unit 31, the torque acquisition unit 32, and the target rotational speed determination unit 34 does not need to perform complicated calculations such as vector control to calculate the torque value Ts. Therefore, an inexpensive microcontroller with limited functions can be used for this integrated circuit device.

[0121] <<Extension of the embodiment>> The invention made by the present inventors has been specifically described above based on an embodiment, but it goes without saying that the invention is not limited thereto and can be modified in various ways without departing from the spirit of the invention.

[0122] For example, in the above embodiment, when the drive control signal generating unit 35 calculates the rotational speed by a sensorless vector control calculation, the target torque calculating unit 38 may use the inverse of the rotational speed calculated by the drive control signal generating unit 35 as the Hall period Hp and calculate the target torque value Tg by the above-mentioned method.

[0123] Furthermore, the method of detecting the rotation speed of the motor is not particularly limited. For example, when the motor 20 is driven by sensorless drive control that does not use a Hall element, the motor drive control device 1 (control circuit 30) may detect the rotation speed using the back electromotive force of the motor 20. In this case, the target torque calculation unit 38 may calculate the target torque value Tg by the above-mentioned method, for example, using the reciprocal of the detected rotation speed as the Hall period Hp.

[0124] Furthermore, the control circuit 3 is not limited to the circuit configuration described above, and various circuit configurations that are configured to meet the objectives of the present invention can be applied to the control circuit 3.

[0125] The above-described flowchart is a specific example, and the present invention is not limited to this flowchart. For example, other processes may be inserted between each step, or the processes may be parallelized.

[0126] The number of phases of the motor driven by the motor drive control device 1 of the above-described embodiment is not limited to three. Furthermore, the number of Hall elements is not limited to three. [Explanation of symbols]

[0127] 1...motor drive control device, 2...motor drive circuit, 2a...inverter circuit, 2b...predrive circuit, 3...control circuit, 20...motor, 21...impeller, 22...fan, 25, 25u, 25v, 25w...rotational position detector (Hall element), 26...rotational speed detector, 27...current detector, 30...target torque determination unit, 31...storage unit, 32...torque acquisition unit, 33...error calculation unit, 34...target rotational speed determination unit, 35...drive control signal generation unit (vector control unit), 36...output command acquisition unit, 37...function selection unit, 38...target torque calculation unit, 40...PI control calculation unit, 41...target rotational speed calculation unit, 50...current measurement unit, 51...Clark conversion unit, 52...Park conversion unit, 53...rotational position detection signal Acquisition unit, 54...electrical angle calculation unit, 55...rotational speed signal acquisition unit, 56...rotation information generation unit, 60...rotational speed PI control unit, 61...magnetic flux PI control unit, 62...torque PI control unit, 63...magnetic flux PI control unit, 64...inverse Park conversion unit, 65...inverse Clarke conversion unit, 66...PWM signal generation unit, 100...fan unit, 310, 310_1 to 310_n...corresponding information (function), EXC...target rotational speed, Id...d-axis current, Id_ref...d-axis current target value, Iq...q-axis current, Iq_ref...q-axis current target value, Iq_g...q-axis current target value, Sd...drive control signal, Sf...output command signal, Si...current detection signal, Sr...rotational speed signal (FG signal), Tg...target torque value, Ts...torque value, ΔT...torque error.

Claims

1. a control circuit that outputs a drive control signal for controlling the drive of the motor; a motor drive circuit that drives the motor based on the drive control signal output from the control circuit, The control circuit includes: a storage unit configured to store correspondence information indicating a relationship between a torque and a value based on a rotation speed of the motor when a motor output of the motor becomes constant at a predetermined value; a target torque determination unit that determines a target torque value from a value based on a rotation speed of the motor by using the correspondence information corresponding to the designated motor output; a torque acquisition unit that acquires a torque value of the motor; a target rotation speed determination unit that determines a target rotation speed of the motor, the target rotation speed being a speed that reduces a difference between the target torque value and the torque value acquired by the torque acquisition unit; a drive control signal generating unit that generates the drive control signal based on the target rotation speed. Motor drive control device.

2. 2. The motor drive control device according to claim 1, The value based on the rotation speed of the motor is a period of a rotation position detection signal, the voltage of which changes periodically according to the rotation position of the rotor of the motor. Motor drive control device.

3. 2. The motor drive control device according to claim 1, The value based on the rotation speed of the motor is the inverse of the rotation speed of the motor. Motor drive control device.

4. The motor drive control device according to any one of claims 1 to 3, the torque acquisition unit acquires, as the torque value, a value of a q-axis current corresponding to a torque of the motor; The target torque determination unit determines a target value of the q-axis current as the target torque value. Motor drive control device.

5. 5. The motor drive control device according to claim 4, The motor has a three-phase coil, the drive control signal generation unit calculates the q-axis current and a d-axis current corresponding to the magnetic flux of the motor based on the current flowing through the coil of each phase of the motor, determines a duty ratio so that the calculated q-axis current and the calculated d-axis current each match a target current value corresponding to the target rotation speed, and outputs a PWM signal having the duty ratio as the drive control signal; The torque acquisition unit acquires the q-axis current calculated by the drive control signal generation unit as the torque value. Motor drive control device.

6. 2. The motor drive control device according to claim 1, the correspondence information includes a function that represents a relationship between a value based on a rotation speed of the motor and a torque, The storage unit stores the function for each of a plurality of specifiable command values ​​of the motor output. Motor drive control device.

7. A motor drive control device according to any one of claims 1 to 3, The motor driven by the motor drive control device; An impeller configured to be rotatable by the rotational force of the motor. Fan unit.

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