Motor drive control device, fan unit, and motor drive control method

Abstract

In a motor drive control device (1), a control circuit (2) comprises, as periods after activation of the control circuit: a first period (T1) in which a designation of an operation mode of a motor (40) is received; and a second period (T2) in which a designation of a target rotational speed, which is a target value of a rotational speed of the motor, is received, and driving of the motor according to the operation mode designated in the first period and the designated target rotational speed is controlled. The control circuit comprises: an operation mode identification unit (20) that identifies a designated operation mode on the basis of a state of a drive command signal (Sc) input during the first period; a target rotational speed identification unit (21) that identifies a target rotational speed on the basis of a drive command signal input during the second period; and a signal generation unit (22) that generates a drive control signal (Sd) during the second period on the basis of the identified operation mode and target rotational speed.

Description

Motor drive control device, fan unit, and motor drive control method

[0001] The present invention relates to a motor drive control device, a fan unit, and a motor drive control method, and relates to, for example, a motor drive control device that controls the rotation of a motor in a fan unit.

[0002] Fans (fan motors) have been widely known as cooling devices for dissipating heat generated inside electrical equipment and the like to the outside and cooling the inside of the equipment. The fan has a motor and an impeller connected to the motor's output shaft, and generates airflow (wind) by rotating the impeller in response to rotation of the motor's output shaft. The fan, for example, constitutes a single fan unit together with a motor drive control device for controlling the drive of the fan motor.

[0003] In general, in fan units, a motor drive control device drives a motor in response to instructions from a host device, causing the fan (motor) to rotate in one direction at a constant rotational speed. However, if the fan unit is used for a long period of time, dust may accumulate on the impeller, making it difficult for the motor to rotate. Fans used outdoors are particularly prone to attracting dust and sand. Therefore, fan units with a function to rotate the fan in the opposite direction are known, with the aim of removing dust from the fan.

[0004] For example, Patent Document 1 discloses a technology in which a fan rotates in the forward direction when the duty ratio of a PWM signal that specifies the rotation speed is between 5% and 45%, and rotates in the reverse direction when the duty ratio of the PWM signal is between 55% and 95%.

[0005] U.S. Patent No. 1,006,0438

[0006] However, according to the technology disclosed in Patent Document 1, the rotation direction of the motor (fan) is specified by the range of the duty ratio of the PWM signal, which has the problem that the range of rotation speeds that can be set by the duty ratio of the PWM signal is narrowed.

[0007] There is also a demand for a fan motor that is capable of changing not only the direction of rotation but also the operating mode, such as the setting range and resolution of the fan rotation speed.

[0008] The present invention has been made in view of the above-mentioned problems, and has an object to make it possible to switch the operation mode of a motor while ensuring a wide setting range for the rotation speed of the motor.

[0009] A motor drive control device according to a representative embodiment of the present invention comprises a signal input terminal for inputting a drive command signal that indicates a drive state of a motor, a control circuit that generates a drive control signal for controlling the rotation of the motor based on the drive command signal input to the signal input terminal, and a drive circuit that drives the motor based on the drive control signal, and includes periods after startup of the control circuit: a first period in which a designation of an operation mode of the motor is accepted, and a second period in which a designation of a target rotation speed that is a target value for the rotation speed of the motor is accepted and drive of the motor is controlled in accordance with the operation mode designated in the first period and the target rotation speed, and the control circuit includes: an operation mode designator that designates the designated operation mode based on the aspect of the drive command signal input to the signal input terminal during the first period; a target rotation speed designator that designates the target rotation speed based on the drive command signal input to the signal input terminal during the second period; and a signal generator that generates the drive control signal during the second period based on the operation mode designated by the operation mode designator and the target rotation speed designated by the target rotation speed designator.

[0010] The motor drive control device according to the present invention makes it possible to change the operation mode of the motor while ensuring a wide setting range for the rotation speed of the motor.

[0011] 1 is a block diagram showing the configuration of a fan unit according to embodiment 1. FIG. 2 is a perspective view schematically showing the appearance of the fan unit according to embodiment 1. FIG. 3 is a diagram showing an example of the relationship between the number of pulses of a drive control signal and an operation mode according to embodiment 1. FIG. 4 is a flowchart showing an example of the flow of processing by the motor drive control device according to embodiment 1. FIG. 5 is a diagram showing an example of the flow of operation mode specification processing (step S1) according to embodiment 1. FIG. 6 is a diagram showing an example of the flow of target rotation speed specification processing (step S2) according to embodiment 1. FIG. 7 is a diagram showing an example of the relationship between a drive command signal and an operation state of a fan in the fan unit according to embodiment 1. FIG. 8 is a diagram showing another example of the relationship between a drive command signal and an operation state of a fan in the fan unit according to embodiment 1. FIG. 9 is a block diagram showing the configuration of a fan unit according to embodiment 2. FIG. 10 is a diagram showing an example of a settable range of motor rotation speed according to embodiment 2. FIG. 11 is a diagram showing an example of a settable range of motor rotation speed according to embodiment 2. FIG. 12 is a flowchart showing an example of the flow of processing by the motor drive control device according to embodiment 2. FIG. 13 is a diagram showing an example of the flow of operation mode specification processing (step S1A). FIG. 14 is a diagram showing an example of the flow of target rotation speed specification processing (step S2A). 10A and 10B are diagrams illustrating an example of the relationship between a drive command signal and the operating state of the fan in the fan unit according to Embodiment 2. FIG. 10B are diagrams illustrating another example of the relationship between a drive command signal and the operating state of the fan in the fan unit according to Embodiment 2.

[0012] 1. Overview of the Embodiments First, an overview of representative embodiments of the invention disclosed in this application will be described. Note that in the following description, as an example, reference numerals in the drawings corresponding to components of the invention are written in parentheses.

[0013] [1] A motor drive control device (1) according to a representative embodiment of the present invention comprises a signal input terminal (P3) for inputting a drive command signal (Sc) that indicates the drive state of a motor (40), a control circuit (2) that generates a drive control signal (Sd) for controlling the rotation of the motor based on the drive command signal input to the signal input terminal, and a drive circuit (3) that drives the motor based on the drive control signal, and includes a first period (T1) after startup of the control circuit for accepting designation of an operation mode of the motor, a target rotation speed that is a target value for the rotation speed of the motor, and the operation mode designated in the first period, and a second period (T2) in which drive of the motor is controlled in accordance with a target rotational speed and a specified operation mode, and the control circuit includes an operation mode specification unit (20, 20A) that specifies the specified operation mode based on the state of the drive command signal input to the signal input terminal during the first period, a target rotational speed specification unit (21, 21A) that specifies the target rotational speed based on the drive command signal input to the signal input terminal during the second period, and a signal generation unit (22) that generates the drive control signal (Sd) during the second period based on the operation mode specified by the operation mode specification unit and the target rotational speed specified by the target rotational speed specification unit.

[0014] [2] In the motor drive control device described in [1] above, the first period may be a period during which a designation of the target rotation speed is not accepted, but a designation of the operation mode is accepted.

[0015] [3] In the motor drive control device described in [2] above, the drive command signal may be a pulse, the operation mode may be associated with each number of pulses of the drive command signal, and the operation mode identification unit may detect the number of pulses of the drive command signal input to the signal input terminal during the first period, and identify the operation mode based on the detected number of pulses.

[0016] [4] In the motor drive control device (1) described in [3] above, the operation mode identification unit (20) may determine that a mode for rotating the motor in a first direction is designated as the operation mode when the number of pulses detected in the first period is a first value, and may determine that a mode for rotating the motor in a second direction opposite to the first direction is designated as the operation mode when the number of pulses detected in the first period is a second value different from the first value.

[0017] [5] In the motor drive control device (1A) described in [3] above, the settable range of the rotational speed of the motor may include a first rotational speed range (R1) and a second rotational speed range (R2) different from the first rotational speed range, and the target rotational speed within the first rotational speed range and the target rotational speed within the second rotational speed range may be respectively assigned for each duty ratio of the drive command signal, and the operation mode identification unit (20A) may determine that a mode in which the motor rotates in a first direction at a rotational speed within the first rotational speed range is designated as the operation mode when the number of pulses detected in the first period is a first value, and may determine that a mode in which the motor rotates in the first direction at a rotational speed within the second rotational speed range is designated as the operation mode when the number of pulses detected in the first period is a second value different from the first value.

[0018] [6] In the motor drive control device described in [5] above, the operation mode identification unit may determine that the operation mode is designated as a mode in which the motor rotates in a second direction opposite to the first direction at a rotational speed within the first rotational speed range when the number of pulses detected in the first period is a third value different from the first value and the second value, and may determine that the operation mode is designated as a mode in which the motor rotates in the second direction at a rotational speed within the second rotational speed range when the number of pulses detected in the first period is a fourth value different from the first value, the second value, and the third value.

[0019] [7] In the motor drive control device described in [2] above, the drive command signal may be a pulse, the operation mode may be associated with each pulse width of the drive command signal, and the operation mode identification unit may detect the pulse width of the drive command signal input to the signal input terminal during the first period, and identify the operation mode based on the detected pulse width.

[0020] [8] In the motor drive control device (1) described in [7] above, the operation mode identification unit (20) may determine that a mode for rotating the motor in a first direction is designated as the operation mode when the pulse width detected in the first period is a first value, and may determine that a mode for rotating the motor in a second direction opposite to the first direction is designated as the operation mode when the pulse width detected in the first period is a second value different from the first value.

[0021] [9] In the motor drive control device (1A) described in [7] above, the settable range of the rotational speed of the motor may include a first rotational speed range and a second rotational speed range different from the first rotational speed range, and the target rotational speed within the first rotational speed range and the target rotational speed within the second rotational speed range may be respectively assigned for each duty ratio of the drive command signal, and the operation mode identification unit (20A) may determine that, when the pulse width detected in the first period is a first value, a mode in which the motor rotates in a first direction at a rotational speed within the first rotational speed range is designated as the operation mode, and may determine that, when the pulse width detected in the first period is a second value different from the first value, a mode in which the motor rotates in the first direction at a rotational speed within the second rotational speed range is designated as the operation mode.

[0022]

[10] In the motor drive control device described in [9] above, the operation mode identification unit may determine that the operation mode is designated as a mode in which the motor rotates in a second direction opposite to the first direction at a rotational speed within the first rotational speed range when the pulse width detected in the first period is a third value different from the first value and the second value, and may determine that the operation mode is designated as a mode in which the motor rotates in the second direction at a rotational speed within the second rotational speed range when the pulse width detected in the first period is a fourth value different from the first value, the second value, and the third value.

[0023]

[11] A fan unit (6, 6A) according to a representative embodiment of the present invention is characterized by comprising the motor (40), an impeller (41) connected to the output shaft of the motor, and a motor drive control device (1, 1A) described in any one of [1] to

[10] above.

[0024]

[12] A method according to a representative embodiment of the present invention is a motor drive control method for controlling the rotation of a motor by a motor drive control device. This method includes a first step (S1 to S3) of generating a drive control signal for controlling the rotation of the motor based on a drive command signal that indicates the drive state of the motor, and a second step (S4) of driving the motor based on the drive control signal.The method includes, as periods after startup of the motor drive control device, a first period (T1) of accepting a designation of an operation mode of the motor, and a second period (T2) of accepting a designation of a target rotation speed that is a target value for the rotation speed of the motor and controlling the drive of the motor in accordance with the operation mode designated in the first period and the target rotation speed.The first step is characterized by including a third step (S1, S1A) of specifying the designated operation mode based on the aspect of the drive command signal inputted in the first period, and a fourth step (S2, S2A, S3) of specifying the target rotation speed based on the drive command signal inputted in the second period, and generating the drive control signal based on the specified target rotation speed and the operation mode designated in the third step.

[0025] 2. Specific Examples of Embodiments Specific examples of embodiments of the present invention will be described below with reference to the drawings. In the following description, components common to the embodiments will be designated by the same reference numerals, and repeated description will be omitted.

[0026] First Embodiment Fig. 1 is a block diagram showing the configuration of a fan unit 6 according to a first embodiment. Fig. 2 is a perspective view schematically showing the appearance of the fan unit 6 according to the first embodiment.

[0027] The fan unit 6 according to the first embodiment is a device that generates wind by rotating an impeller. The fan unit 6 can be used, for example, as a cooling device that exhausts heat generated inside a device to the outside and cools the inside of the device.

[0028] 1, the fan unit 6 includes a fan 4 and a motor drive control device 1. The fan 4 includes a motor 40 and an impeller 41 attached to the rotating shaft of the motor 40. The fan 4 is, for example, an axial flow fan. The motor 40 is, for example, a three-phase brushless DC (Direct Current) motor.

[0029] The motor drive control device 1 is a device for controlling the drive of a motor 40. As shown in Fig. 1, the motor drive control device 1 includes, for example, a plurality of external terminals, a control circuit 2, a drive circuit 3, and a position detector 5. 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 include other components in addition to those shown in Fig. 1.

[0030] As shown in FIG. 1, the motor drive control device 1 has a plurality of external terminals, such as a power supply terminal P1, a ground terminal P2, a signal input terminal P3 for inputting a signal, and a signal output terminal P4 for outputting a signal.

[0031] The fan unit 6 constitutes a so-called four-wire fan motor. Specifically, as shown in Figures 1 and 2, a signal line 49 is connected to the power supply terminal P1, a signal line 50 is connected to the ground terminal P2, a signal line 51 is connected to the signal input terminal P3, and a signal line 52 is connected to the signal output terminal P4. As shown in Figure 2, each of the signal lines 49 to 51 is drawn out of the casing 47 of the fan unit 6 and connected to a host device (not shown) and a power supply device (not shown) provided outside the fan unit 6, thereby electrically connecting the motor drive control device 1 to the power supply device and the host device.

[0032] A DC voltage Vdc is supplied to the power supply terminal P1 from the power supply device via a signal line 49. This supplies the power supply voltage to the control circuit 2 and the drive circuit 3. Note that a regulator may be provided in the motor drive control device 1, and the regulator may generate a new DC voltage from the DC voltage Vdc and supply it as the power supply voltage to the control circuit 2. The ground terminal P2 is connected to the ground potential GND via a signal line 50.

[0033] As will be described later, a drive command signal Sc instructing the drive state of the motor is input to the signal input terminal P3. For example, the signal input terminal P3 is connected to a higher-level device, and the drive command signal Sc output from the higher-level device is input to the signal input terminal P3. As will be described later, the signal output terminal P4 outputs a rotation state signal So. For example, the signal output terminal P4 is connected to a higher-level device, and the rotation state signal So output from the control circuit 2 is input to the higher-level device from the signal output terminal P4.

[0034] When the fan unit 6 receives power from a host device, the power supply terminal P1 and the ground terminal P2 may be connected to a power line and a ground line, respectively, within the host device.

[0035] The position detector 5 is a device for detecting the rotational position of the rotating shaft (rotor) of the motor 40. The position detector 5 is, for example, a Hall element. For example, three Hall elements corresponding to the respective phases (U phase, V phase, W phase) of the motor 40 are arranged at approximately equal intervals around the rotor (magnet) of the motor 40. The number of Hall elements is not particularly limited.

[0036] The position detector 5 outputs a rotational position detection signal (Hall signal) Sh to the control circuit 2. The rotational position detection signal Sh is a signal that indicates the rotational position of the motor 40, i.e., a signal that corresponds to the rotational position of the rotor (magnet) of the motor 40.

[0037] The position detector 5 may be any device that has the function of detecting position information of the rotating shaft (rotor) of the motor 40 and outputting it as an electrical signal, and may be, for example, a rotary encoder. Alternatively, without providing the position detector 5, the rotational position of the motor 40 may be detected by a so-called sensorless method in which the control circuit 2 detects back electromotive voltages induced in each phase (U phase, V phase, W phase) of the motor 40 and detects the rotational position of the motor 40 based on the back electromotive voltages.

[0038] The control circuit 2 is a circuit that performs overall control of the motor drive control device 1. The control circuit 2 generates a drive control signal Sd for controlling the rotation of the motor 40. The control circuit 2 is, for example, a program processing device (e.g., various types of computers such as a microcontroller) that has 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 buses or dedicated lines. Details of the control circuit 2 will be described later.

[0039] The drive circuit 3 is a circuit that drives the motor 40 based on the drive control signal Sd. The drive circuit 3 includes, for example, an inverter circuit (not shown) and a pre-drive circuit (not shown). The inverter circuit outputs a drive signal to the motor 40 based on the output signal from the pre-drive circuit, and energizes the three-phase coils of the motor 40. The rotation direction of the motor 40 can be changed by switching the order in which the three-phase coils are energized. For example, the inverter circuit is configured by a pair of series circuits of two switch elements connected in series between a DC voltage Vdc and a ground potential GND, each pair being arranged for one phase of the coil. In each pair of two switch elements, a terminal of each phase of the motor 40 is connected to the connection point between the switch elements.

[0040] The pre-drive circuit generates an output signal for driving the inverter circuit based on the drive control signal Sd and outputs it to the inverter circuit. The pre-drive circuit generates and outputs a drive signal for driving each switch element of the inverter circuit based on, for example, the drive control signal Sd. The drive signal output from the pre-drive circuit turns each switch element constituting the inverter circuit on / off, thereby supplying power to each phase of the motor 40 and rotating the rotor of the motor 40.

[0041] In the motor drive control device 1, at least some of the functional parts of the control circuit 2 and the drive circuit 3 may be packaged as a single semiconductor integrated circuit device (IC: Integrated Circuit), or the drive circuit 3 and the control circuit 2 may each be packaged as individual semiconductor integrated circuit devices.

[0042] Next, the control circuit 2 will be described in detail.

[0043] Based on the drive command signal Sc input to the signal input terminal P3, the control circuit 2 generates a drive control signal Sd for controlling the rotation of the motor 40. Specifically, the control circuit 2 has a plurality of operating modes related to the drive control of the motor 40 and has a function of switching the operating modes in accordance with the drive command signal Sc. The control circuit 2 also has a function of generating the drive control signal Sd for the motor 40 in accordance with the operating mode specified by the drive command signal Sc.

[0044] In the first embodiment, the operating modes include a first mode in which motor 40 rotates in a first direction, and a second mode in which motor 40 rotates in a second direction opposite to the first direction. In the following description, the first direction may be referred to as the "forward direction," rotation in the forward direction may be referred to as "positive rotation," the second direction may be referred to as the "reverse direction," and rotation in the negative direction may be referred to as "negative rotation." Furthermore, the first mode may be referred to as the "positive rotation mode," and the second mode may be referred to as the "negative rotation mode."

[0045] The control circuit 2 has, for example, a first period T1 and a second period T2 as periods after the control circuit 2 is started.

[0046] The first period T1 is a period during which the control circuit 2 accepts a designation of the operating mode of the motor 40. During the first period T1, the control circuit 2 identifies the designated operating mode based on the state of the input drive command signal Sc. The first period T1 may be a period (OFF period) during which the target rotation speed, which is the target value of the rotation speed of the motor 40, is not identified according to the input drive command signal Sc. That is, the first period T1 is a period during which the control circuit 2 does not accept a designation of the target rotation speed, which is the target value of the rotation speed of the motor 40, but accepts a designation of the operating mode of the motor. In other words, the control circuit 2 does not analyze the drive command signal Sc input during the first period T1 as a signal designating the target rotation speed, but analyzes the drive command signal Sc input during the first period T1 as a signal designating the operating mode.

[0047] The second period T2 is a period during which the control circuit 2 controls the drive of the motor 40 in accordance with the operation mode and target rotation speed specified in the first period T1. The control circuit 2 controls the rotation of the motor 40 by generating a drive control signal Sd based on the operation mode identified in the first period T1 and the target rotation speed specified by the drive command signal Sc input in the second period T2.

[0048] For example, the control circuit 2 transitions to the first period T1 after activation of the control circuit 2. If a designation of an operation mode is accepted during the first period T1, the control circuit 2 transitions to the second period T2 after the first period T1 has elapsed. On the other hand, if a designation of an operation mode is not accepted during the first period T1, the control circuit 2 transitions to a new first period T1 after the first period T1 has elapsed.

[0049] As shown in FIG. 1 , the control circuit 2 has a drive command signal analyzer 27, a signal generator 22, a rotational speed calculator 23, and a rotational state signal generator 24 as functional blocks for realizing the above-mentioned functions. These functional blocks are realized, for example, by a CPU in the control circuit 2 executing various arithmetic processes in accordance with programs stored in memory and controlling peripheral circuits such as an A / D converter circuit and an input / output interface circuit based on the results of the processes. Note that some or all of the above-mentioned functional blocks may be realized by dedicated circuits (such as dedicated hardware logic circuits). Each functional block will be described below.

[0050] The drive command signal analysis unit 27 analyzes the drive command signal Sc input from an external device (host device) to the signal input terminal P3. Specifically, the drive command signal analysis unit 27 includes an operation mode identification unit 20 and a target rotation speed identification unit 21.

[0051] The operation mode specifying unit 20 is a functional unit for specifying the operation mode of the motor 40. The operation mode specifying unit 20 specifies the specified operation mode based on the state of the drive command signal Sc input to the signal input terminal P3 during the first period T1.

[0052] Here, the drive command signal Sc is a signal that indicates a target drive state of the motor 40. The drive command signal Sc is, for example, a pulse. In other words, the drive command signal Sc is a binary signal that can take on a voltage corresponding to a first logic level or a voltage corresponding to a second logic level that is opposite to the first logic level. In the present embodiment, as an example, the first logic level is a high level (for example, a DC voltage Vdc) and the second logic level is a low level (for example, a ground potential), but this is not limiting.

[0053] For example, the operation mode specifying unit 20 detects the number of pulses of the drive command signal Sc input during the first period T1, and specifies the operation mode based on the detected number of pulses.

[0054] FIG. 3 is a diagram showing an example of the relationship between the number of pulses of the drive command signal Sc and the operation mode in the first embodiment.

[0055] 3, an operation mode is associated with each number of pulses of the drive command signal Sc. For example, if the number of pulses of the drive command signal Sc input to the signal input terminal P3 during the first period T1 is "1," the operation mode specification unit 20 determines that the "forward rotation mode" has been specified. Also, for example, if the number of pulses of the drive command signal Sc input to the signal input terminal P3 during the first period T1 is "2," the operation mode specification unit 20 determines that the "reverse rotation mode" has been specified.

[0056] Furthermore, for example, when the number of pulses of the drive command signal Sc input to the signal input terminal P3 during the first period T1 is "0," the operation mode identification unit 20 determines that an instruction to stop the rotation of the motor 40 (stop mode) has been issued. Note that when the number of pulses of the drive command signal Sc is 3 or more, the operation mode identification unit 20 may determine that an instruction to stop the rotation of the motor 40 has been issued, for example.

[0057] For example, correspondence information 25 indicating the relationship between the number of pulses of the drive command signal Sc and the operation mode is stored in advance in a storage device (not shown) within the control circuit 2. The correspondence information 25 may be, for example, information in a table format as shown in FIG. 3 or may be a function. The operation mode identification unit 20, for example, refers to the correspondence information 25 to identify the operation mode from the number of pulses of the drive command signal Sc input to the signal input terminal P3 during the first period T1. The operation mode identification unit 20 outputs information on the identified operation mode. For example, the operation mode identification unit 20 outputs designated rotation direction information Str indicating the rotation direction of the motor 40 as information on the identified operation mode.

[0058] The target rotation speed specifying unit 21 is a functional unit that specifies the target rotation speed of the motor 40 specified by the drive command signal Sc. Specifically, the target rotation speed specifying unit 21 specifies the target rotation speed based on the drive command signal Sc input to the signal input terminal P3 during the second period T2. More specifically, the target rotation speed specifying unit 21 does not analyze the drive command signal Sc input during the first period T1, but analyzes the drive command signal Sc input during the second period T2 to specify the target rotation speed. For example, when a PWM signal is input as the drive command signal Sc during the second period T2, the target rotation speed specifying unit 21 specifies the target rotation speed by analyzing the duty ratio of the input PWM signal.

[0059] For example, correspondence relationship information 26 indicating the relationship between the duty ratio of the drive command signal Sc and the target rotation speed is stored in advance in a storage device (not shown) in the control circuit 2. The correspondence relationship information 26 is, for example, data in which the target rotation speed is assigned to each duty ratio from a minimum duty ratio (e.g., 5%) to a maximum duty ratio (e.g., 95%). The correspondence relationship information 26 may be, for example, information in the form of a table or a function.

[0060] The target rotation speed specifying unit 21 specifies the target rotation speed from the duty ratio of the drive command signal Sc input to the signal input terminal P3 during the second period T2, for example, by referring to the correspondence information 26. The target rotation speed specifying unit 21 outputs information Stv of the specified target rotation speed.

[0061] The rotation speed calculation unit 23 is a functional unit that calculates the actual rotation speed of the motor 40. The rotation speed calculation unit 23 calculates the rotation speed of the motor 40 using a known calculation method based on the rotation position detection signal Sh, and provides rotation speed information Sv to the signal generation unit 22. In the case of the sensorless system described above, for example, the rotation speed calculation unit 23 detects a back electromotive force induced in each phase (U phase, V phase, W phase) of the motor 40, and calculates the rotation speed of the motor 40 based on the back electromotive force.

[0062] The signal generating unit 22 is a functional unit that generates a drive control signal Sd. The signal generating unit 22 generates the drive control signal Sd during the second period T2 based on the operation mode identified by the operation mode identifying unit 20 and the target rotation speed identified by the target rotation speed identifying unit 21. Specifically, the signal generating unit 22 generates and outputs the drive control signal Sd during the second period T2 based on information Str on the designated rotation direction (operation mode) of the motor 40, information Stv on the target rotation speed of the motor 40, and information Sv on the rotation speed of the motor 40.

[0063] More specifically, during the second period T2, the signal generating unit 22 calculates the error between the target rotation speed and the rotation speed of the motor, and calculates the operation amount of the motor 40 so that the error becomes zero, for example, by a PID (Proportional Integral Differential) control calculation, and generates a PWM signal having a duty ratio according to the operation amount so that the motor 40 rotates in the rotation direction (forward direction / reverse direction) based on the specified operation mode, and outputs the PWM signal as the drive control signal Sd.

[0064] In the case of open-loop control, which does not attempt to maintain the rotational speed of the motor 40 but instead attempts to rotate it with a constant force, the signal generating unit 22 generates a PWM signal having a duty ratio according to the amount of operation for maintaining the predetermined rotational speed, and outputs it as the drive control signal Sd.

[0065] The rotation state signal generator 24 is a functional block that generates a rotation state signal So indicating the rotation state of the motor. The rotation state signal generator 24 generates the rotation state signal So indicating the rotation state of the motor based on the rotation position detection signal Sh output from the position detector 5, and outputs it from the signal output terminal P4. Specifically, the rotation state signal generator 24 generates the rotation state signal So having a frequency based on the rotation speed of the motor 40 and a predetermined duty ratio, and outputs it from the signal output terminal P4.

[0066] Here, the rotation state signal So is, for example, an FG (Frequency Generator) signal having a frequency corresponding to the rotation speed of the motor 40 and a duty ratio of 50%. The rotation state signal generating unit 24 generates the FG signal by a known method, for example, based on a Hall signal serving as the rotation position detection signal Sh.

[0067] The rotation state signal generator 24 may output the rotation state signal So by including information indicating the rotation direction of the motor 40. For example, when the motor 40 is rotating forward, the rotation state signal generator 24 may output a signal having a frequency corresponding to the period of the rotation position detection signal Sh and a duty ratio of 50% as the rotation state signal So from the signal output terminal P4. On the other hand, when the motor 40 is rotating backward, the rotation state signal generator 24 may output a signal having a frequency corresponding to the period of the rotation position detection signal Sh and a duty ratio other than 50% as the rotation state signal So from the signal output terminal P4.

[0068] FIG. 4 is a flowchart showing an example of the flow of processing by the motor drive control device 1 according to the first embodiment.

[0069] For example, the control circuit 2 is activated when the DC voltage Vdc is applied to the fan unit 6. First, the control circuit 2 shifts to a first period T1 and executes an operation mode identification process (step S2).

[0070] FIG. 5 is a diagram showing an example of the flow of the operation mode specifying process (step S1) according to the first embodiment.

[0071] 5, in the operation mode identification process (step S1), the operation mode identification unit 20 of the control circuit 2 starts counting the first period T1 (step S11). Next, the operation mode identification unit 20 counts the number of pulses of the drive command signal Sc input to the signal input terminal P3 during the first period T1 (step S12). Next, the operation mode identification unit 20 determines whether the first period T1 has elapsed (step S13). If the first period T1 has not elapsed (step S13: NO), the operation mode identification unit 20 continues counting the number of pulses.

[0072] If the first period T1 has elapsed (step S13: YES), the operation mode identification unit 20 determines whether the number of pulses N counted in step S12 is "1" (step S14). If the number of pulses N is 1 (step S14: YES), the operation mode identification unit 20 determines that the "forward rotation mode" is specified as the operation mode (step S16). If the number of pulses N is not 1 (step S14: NO), the operation mode identification unit 20 determines whether the number of pulses N is "2" (step S15). If the number of pulses N is 2 (step S15: YES), the operation mode identification unit 20 determines that the "reverse rotation mode" is specified as the operation mode (step S16). If the number of pulses N is not 2 (step S15: NO), for example, the operation mode identification unit 20 starts timing a new first period T1 (step S11).

[0073] If the operation mode is identified in step S16 or step S17, the operation mode identification process (step S1) ends. As shown in Fig. 4, after the operation mode identification process (step S1) ends, the control circuit 2 executes a target rotation speed identification process (step S2).

[0074] FIG. 6 is a diagram showing an example of the flow of the target rotation speed specifying process (step S2) in the first embodiment.

[0075] As shown in Fig. 6, in the target rotation speed identification process (step S2), the control circuit 2 first transitions to the second period T2 (step S21). During the second period T2, the target rotation speed identification unit 21 of the control circuit 2 detects the duty ratio of the PWM signal serving as the drive command signal Sc input to the signal input terminal P3 (step S22). Next, the target rotation speed identification unit 21 identifies the target rotation speed based on the duty ratio detected in step S22 using the method described above (step S23). This completes the target rotation speed identification process (step S2).

[0076] If a state in which a PWM signal is not input as the drive command signal Sc continues for a predetermined period T0 after the transition to the second period T2, the control circuit 2 may transition to the first period T1.

[0077] 4 , after the target rotation speed determination process (step S2) is completed, the control circuit 2 generates a drive control signal Sd during the second period T2 (step S3). Specifically, the signal generator 22 of the control circuit 2 generates and outputs the drive control signal Sd using the method described above so that the motor 40 rotates at the target rotation speed determined in step S2 in the direction (forward or reverse) based on the operating mode determined in step S1 during the second period T2. The drive circuit 3 drives the motor 40 based on the drive control signal Sd, causing the fan 4 to rotate (step S4).

[0078] FIG. 7 is a diagram showing an example of the relationship between the drive command signal Sc and the operating state of the fan 4 in the fan unit 6 according to the first embodiment.

[0079] 7, reference numeral 301 indicates a change over time in the drive command signal Sc, and reference numeral 302 indicates a change over time in the operating state of the fan 4 (motor 40). Here, as an example, it is assumed that when the duty ratio of the drive command signal Sc is 50%, the target rotation speed is set to 5000 rpm, and when the duty ratio of the drive command signal Sc is 90%, the target rotation speed is set to 9500 rpm.

[0080] 7, for example, when the control circuit 2 is started at time t0, a drive command signal Sc of the second logic level (low level) is input to the control circuit 2. At this time, the control circuit 2 generates a drive control signal Sd to stop the rotation of the motor 40.

[0081] The control circuit 2 transitions to a first period T1 at time t1, a predetermined period T0 after the start of the control circuit 2. As shown in Fig. 7, assume that one pulse is input as the drive command signal Sc during the first period T1, from time t1 to time t2. In this case, the control circuit 2 determines that the "forward rotation mode" has been specified as the operating mode, and transitions to a second period T2 from time t2.

[0082] After time t2, when a PWM signal with a duty ratio of 50% is input as the drive command signal Sc, the control circuit 2 sets the target rotation speed to 5000 rpm using the method described above, and generates a drive control signal Sd so that the motor 40 rotates forward at a rotation speed of 5000 rpm.

[0083] At time t3 when the duty ratio of the drive command signal Sc is changed from 50% to 90%, the control circuit 2 changes the target rotation speed from 5000 rpm to 9500 rpm and generates a drive control signal Sd so that the motor 40 rotates forward at a rotation speed of 9500 rpm.

[0084] Thereafter, at time t4, the input of the PWM signal as the drive command signal Sc stops, and at time t5 after a predetermined period T0 has elapsed, the control circuit 2 shifts to the first period T1 and stops the rotation of the motor 40.

[0085] As shown in Fig. 7, suppose two pulses are input as the drive command signal Sc during a first period T1 from time t5 to time t6. In this case, the control circuit 2 determines that the "reverse rotation mode" has been specified as the operating mode, and transitions to a second period T2 from time t6. As shown in Fig. 7, if a PWM signal with a duty ratio of 90% is input as the drive command signal Sc after time t6, the control circuit 2 sets the target rotation speed to 9,500 rpm using the method described above, and generates a drive control signal Sd so that the motor 40 rotates in the reverse direction at a rotation speed of 9,500 rpm.

[0086] At time t7 when the duty ratio of the drive command signal Sc is changed from 90% to 50%, the control circuit 2 changes the target rotation speed from 9500 rpm to 5000 rpm and generates a drive control signal Sd so that the motor 40 rotates in the negative direction at a rotation speed of 5000 rpm.

[0087] Thereafter, at time t8, the input of the PWM signal as the drive command signal Sc stops, and at time t9 after a predetermined period T0 has elapsed, the control circuit 2 transitions to the first period T1 and stops the rotation of the motor 40.

[0088] As described above, in the motor drive control device 1 according to embodiment 1, the control circuit 2 identifies the operating mode based on the state of the drive command signal Sc input to the signal input terminal P3 during the first period T1, identifies the target rotation speed of the motor 40 based on the drive command signal Sc input to the signal input terminal P3 during the second period T2, and controls the driving of the motor 40 by generating a drive control signal Sd based on the identified operating mode and target rotation speed.

[0089] According to this, the control circuit 2 has, as periods after startup of the control circuit 2, a first period T1 for accepting an operation mode specification and a second period T2 for controlling the drive of the motor 40, so that various operation modes can be assigned to each state of the drive command signal Sc input during the first period T1, thereby enabling switching of the operation mode. Furthermore, because the target rotation speed of the motor 40 can be specified by the drive command signal Sc input during the second period T2, which is different from the first period T1, the range of duty ratios that can be assigned as target rotation speeds is not narrowed. In this way, the motor drive control device 1 according to the first embodiment enables switching of the motor operation mode while ensuring a wide setting range for the motor rotation speed.

[0090] Furthermore, according to the motor drive control device 1, the operation mode can be easily identified simply by detecting the number of pulses of the drive command signal Sc input during the first period T1.

[0091] For example, as described above, the control circuit 2 determines that the forward rotation mode is specified as the operating mode when the number of pulses detected during the first period T1 is 1, and determines that the reverse rotation mode is specified as the operating mode when the number of pulses detected during the first period T1 is 2. This makes it easy to switch the rotation direction of the motor 40 by changing the number of pulses input during the first period T1.

[0092] In the first embodiment, the operation mode is identified by analyzing the "number of pulses" of the drive command signal Sc input during the first period T1, but this is not limiting. For example, the operation mode may be identified by analyzing the "pulse width" of the drive command signal Sc input during the first period T1. That is, in the first embodiment, the operation mode is associated with each pulse width of the drive command signal Sc, and the operation mode identification unit 20 may detect the pulse width of the drive command signal Sc input to the signal input terminal P3 during the first period T1 and identify the operation mode based on the detected pulse width.

[0093] FIG. 8 is a diagram showing another example of the relationship between the drive command signal Sc and the operating state of the fan 4 in the fan unit 6 according to the first embodiment.

[0094] The unit pulse width of the pulse input as the drive command signal Sc is defined as W. Fig. 8 shows, as an example, a case where the "positive rotation mode" is assigned to the pulse width W, and the "negative rotation mode" is assigned to the pulse width (W x 2).

[0095] As shown in Fig. 8, suppose the pulse width of the drive command signal Sc input during the first period T1 from time t1 to time t2 is "W." In this case, the control circuit 2 determines that the "forward rotation mode" has been specified as the operating mode. Also, as shown in Fig. 8, suppose the pulse width of the drive command signal Sc input during the first period T1 from time t5 to time t6 is "W x 2." In this case, the control circuit 2 determines that the "reverse rotation mode" has been specified as the operating mode.

[0096] In this way, by changing the width of the pulse input during the first period T1 in the motor drive control device 1 according to the first embodiment, the rotation direction of the motor 40 can be easily switched.

[0097] Second Embodiment FIG. 9 is a block diagram showing the configuration of a fan unit 6 according to a second embodiment.

[0098] The fan unit 6A of embodiment 2 differs from the fan unit 6 of embodiment 1 in that it is capable of switching between three or more operating modes, but is otherwise similar to the fan unit 6 of embodiment 1.

[0099] Specifically, the motor drive control device 1A according to the second embodiment has a first rotation speed range R1 and a second rotation speed range R2 different from the first rotation speed range R1 as the settable range of the rotation speed of the motor 40.

[0100] 10A and 10B are diagrams showing an example of a settable range of the rotation speed of motor 40 according to the second embodiment.

[0101] Fig. 10A shows an example of the first rotation speed range R1, and Fig. 10B shows an example of the second rotation speed range R2. In Fig. 10A and Fig. 10B, the horizontal axis represents the duty ratio [%] of the PWM signal serving as the drive command signal Sc, and the vertical axis represents the motor rotation speed [rpm].

[0102] As shown in Fig. 10A, in the first rotation speed range R1, for example, rotation speeds from 0 rpm to 1000 rpm correspond to duty ratios from 0% to 100%, respectively. Also, as shown in Fig. 10B, in the second rotation speed range R2, for example, rotation speeds from 0 rpm to 10000 rpm correspond to duty ratios from 0% to 100%, respectively.

[0103] The minimum setting width of the rotation speed in the first rotation speed range R1 is 10 rpm / % and the minimum setting width of the rotation speed in the second rotation speed range R2 is 100 rpm / %. Therefore, according to the first rotation speed range R1, the settable range of the target rotation speed is narrow, but the resolution of the target rotation speed is high. On the other hand, according to the second rotation speed range R2, the settable range of the target rotation speed is wide, but the resolution of the target rotation speed is low.

[0104] The fan unit 6A according to the second embodiment is capable of switching not only the rotation direction of the motor 40 but also the settable range of the rotation speed of the motor 40. That is, the fan unit 6A has two operating modes: a "low-speed, forward rotation mode" in which the motor 40 rotates in a first direction (forward direction) at a rotation speed within a first rotation speed range R1, and a "high-speed, forward rotation mode" in which the motor 40 rotates in the first direction (forward direction) at a rotation speed within a second rotation speed range R2. The fan unit 6A also has two operating modes: a "low-speed, negative rotation mode" in which the motor 40 rotates in a second direction (reverse direction) at a rotation speed within the first rotation speed range R1, and a "high-speed, negative rotation mode" in which the motor 40 rotates in the second direction (forward direction) at a rotation speed within the second rotation speed range R2.

[0105] In the second embodiment, a drive command signal analyzer 27A that analyzes the drive command signal Sc includes an operation mode identifier 20A and a target rotation speed identifier 21A. The operation mode identifier 20A detects the “number of pulses” of the drive command signal Sc input during the first period T1, and identifies the specified operation mode based on the number of pulses.

[0106] FIG. 11 is a diagram showing an example of the relationship between the number of pulses of the drive command signal Sc and the operation mode in the second embodiment.

[0107] As shown in FIG. 11 , an operation mode is associated with each number of pulses of the drive command signal Sc. For example, if the number of pulses of the drive command signal Sc input to the signal input terminal P3 during the first period T1 is "1," the operation mode specification unit 20A determines that the "low-speed, forward rotation mode" has been specified. If the number of pulses of the drive command signal Sc input to the signal input terminal P3 during the first period T1 is "2," the operation mode specification unit 20A determines that the "high-speed, forward rotation mode" has been specified. If the number of pulses of the drive command signal Sc input to the signal input terminal P3 during the first period T1 is "3," the operation mode specification unit 20A determines that the "low-speed, reverse rotation mode" has been specified. If the number of pulses of the drive command signal Sc input to the signal input terminal P3 during the first period T1 is "4," the operation mode specification unit 20A determines that the "high-speed, reverse rotation mode" has been specified.

[0108] Furthermore, for example, when the number of pulses of the drive command signal Sc input to the signal input terminal P3 during the first period T1 is "0," the operation mode identification unit 20A determines that an instruction to stop the rotation of the motor 40 (stop mode) has been issued. Note that when the number of pulses of the drive command signal Sc is 5 or more, for example, the operation mode identification unit 20A may determine that an instruction to stop the rotation of the motor 40 has been issued.

[0109] For example, correspondence information 25A indicating the relationship between the number of pulses of the drive command signal Sc and the operation mode is stored in advance in a storage device (not shown) in the control circuit 2. The correspondence information 25A may be, for example, information in a table format as shown in FIG. 11 or may be a function. The operation mode identification unit 20A, for example, refers to the correspondence information 25A to identify the operation mode from the number of pulses of the drive command signal Sc input to the signal input terminal P3 during the first period T1. The operation mode identification unit 20A outputs information Str of the specified rotation direction (operation mode).

[0110] The target rotation speed specifying unit 21A is a functional unit that specifies the target rotation speed of the motor 40 specified by the drive command signal Sc. Specifically, the target rotation speed specifying unit 21A specifies the target rotation speed based on the drive command signal Sc input to the signal input terminal P3 during the second period T2. Specifically, when a PWM signal is input as the drive command signal Sc during the second period T2, the target rotation speed specifying unit 21A specifies the target rotation speed by analyzing the duty ratio of the PWM signal.

[0111] For example, as shown in Fig. 9, correspondence relationship information 26L indicating the relationship between the duty ratio of the PWM signal serving as the drive command signal Sc and the rotation speed in a first rotation speed range R1 (low speed), and correspondence relationship information 26H indicating the relationship between the duty ratio of the PWM signal serving as the drive command signal Sc and the rotation speed in a second rotation speed range R2 (high speed) are pre-stored in a storage device (not shown) within the control circuit 2. The correspondence relationship information 26L and 26H may be, for example, functions such as those shown in Figs. 10A and 10B, or may be information in a table format. Hereinafter, when there is no need to distinguish between the correspondence relationship information 26L and the correspondence relationship information 26H, they may be referred to as "correspondence information 26."

[0112] The target rotation speed specifying unit 21A first selects correspondence relationship information 26 corresponding to the operation mode specified by the operation mode specifying unit 20A. For example, the target rotation speed specifying unit 21A selects correspondence relationship information 26L when the operation mode is the "low-speed, positive rotation mode" or the "low-speed, negative rotation mode," and selects correspondence relationship information 26H when the operation mode is the "high-speed, positive rotation mode" or the "high-speed, negative rotation mode."

[0113] The target rotation speed specifying unit 21A specifies the target rotation speed from the duty ratio of the drive command signal Sc input to the signal input terminal P3 during the second period T2 by referring to the selected correspondence information 26. The target rotation speed specifying unit 21 outputs information Stv of the specified target rotation speed.

[0114] FIG. 12 is a flowchart showing an example of the flow of processing by the motor drive control device 1A according to the second embodiment.

[0115] For example, when the DC voltage Vdc is applied to the fan unit 6A, the control circuit 2A is activated. First, the control circuit 2A enters a first period T1 and executes an operation mode identification process (step S2A).

[0116] 13A and 13B are diagrams showing an example of the flow of the operation mode identification process (step S1A).

[0117] As shown in FIG. 13A, in the operation mode identification process (step S1A), the processes from step S11 to step S13 are the same as the processes by the control circuit 2 according to the first embodiment.

[0118] After step S13, the operation mode specifying unit 20 of the control circuit 2A according to the second embodiment determines whether the number of pulses N counted in step S12 is "1" (step S14A). If the number of pulses N is 1 (step S14A: YES), the operation mode specifying unit 20A determines that the "low-speed, forward rotation mode" is specified as the operation mode (step S16A). If the number of pulses N is not 1 (step S14A: NO), the operation mode specifying unit 20A determines whether the number of pulses N is "2" (step S15A).

[0119] If the number of pulses N is 2 (step S15A: YES), the operation mode specifying unit 20A determines that the "high-speed forward rotation mode" is specified as the operation mode (step S17A). If the number of pulses N is not 2 (step S15A: NO), the operation mode specifying unit 20A determines whether the number of pulses N is "3" (step S18A).

[0120] If the number of pulses N is 3 (step S18A: YES), the operation mode specifying unit 20A determines that the "low-speed / negative rotation mode" is specified as the operation mode (step S20A). If the number of pulses N is not 3 (step S18A: NO), the operation mode specifying unit 20A determines whether the number of pulses N is "4" (step S19A).

[0121] If the number of pulses N is 4 (step S19A: YES), the operation mode specifying unit 20A determines that the "high-speed, negative rotation mode" is specified as the operation mode (step S21A). If the number of pulses N is not 4 (step S19A: NO), for example, the operation mode specifying unit 20A starts timing a new first period T1 (step S11).

[0122] If the operation mode is identified in step S16 or step S17, the operation mode identification process (step S1) ends. As shown in Fig. 12, after the operation mode identification process (step S1A) ends, the control circuit 2 executes a target rotation speed identification process (step S2A).

[0123] FIG. 14 is a diagram showing an example of the flow of the target rotation speed specifying process (step S2A).

[0124] As shown in FIG. 14, in the target rotation speed identification process (step S2A), first, the target rotation speed identification unit 21A of the control circuit 2A selects the correspondence information 26 corresponding to the operation mode identified in step S1A using the above-described method (step S20A).

[0125] Next, the control circuit 2A transitions to the second period T2 (step S21). During the second period T2, the target rotation speed specifying unit 21A detects the duty ratio of the PWM signal as the drive command signal Sc input to the signal input terminal P3 (step S22). Next, the target rotation speed specifying unit 21A uses the correspondence information 26 selected in step S20A to specify the target rotation speed corresponding to the duty ratio detected in step S22 (step S23A). This completes the target rotation speed specifying process (step S2A).

[0126] If a state in which a PWM signal is not input as the drive command signal Sc continues for a predetermined period T0 after the transition to the second period T2, the control circuit 2 may transition to the first period T1.

[0127] 12 , after the target rotation speed determination process (step S2A) is completed, the control circuit 2A generates a drive control signal Sd during the second period T2 (step S3). Specifically, the signal generating unit 22 of the control circuit 2A generates and outputs the drive control signal Sd using the method described above so that the motor 40 rotates at the target rotation speed determined in step S2A in the direction (forward or reverse) based on the operating mode determined in step S1A during the second period T2. The drive circuit 3 drives the motor 40 based on the drive control signal Sd, causing the fan 4 to rotate.

[0128] FIG. 15 is a diagram showing an example of the relationship between the drive command signal Sc and the operating state of the fan 4 in the fan unit 6A according to the second embodiment.

[0129] 15, reference numeral 301A indicates a change over time in the drive command signal Sc, and reference numeral 302A indicates a change over time in the operating state of the fan 4 (motor 40). Here, as an example, when the duty ratio of the drive command signal Sc is 50%, the target rotation speed is set to 500 rpm in the first rotation speed range R1, and the target rotation speed is set to 5000 rpm in the second rotation speed range R2.

[0130] 15, for example, when the control circuit 2A is started at time t0, a drive command signal Sc of the second logic level (low level) is input to the control circuit 2A. At this time, the control circuit 2A generates a drive control signal Sd to stop the rotation of the motor 40.

[0131] At time t1, a predetermined period T0 has elapsed since the start-up time t0, the control circuit 2A transitions to the first period T1. As shown in Fig. 15, assume that one pulse is input as the drive command signal Sc during the first period T1, from time t1 to time t2. In this case, the control circuit 2A determines that the "low speed / forward rotation mode" has been specified as the operating mode, transitions to the second period T2 at time t2, and selects the correspondence relationship information 26L corresponding to the first rotation speed range R1 (low speed).

[0132] After time t2, when a PWM signal with a duty ratio of 50% is input as the drive command signal Sc, the control circuit 2A sets the target rotation speed to 500 rpm based on the correspondence information 26L using the method described above, and generates a drive control signal Sd so that the motor 40 rotates forward at a rotation speed of 500 rpm.

[0133] Thereafter, at time t3, the input of the PWM signal as the drive command signal Sc stops, and at time t4 after the predetermined period T0 has elapsed, the control circuit 2A shifts to the first period T1 and stops the rotation of the motor 40.

[0134] 15, suppose two pulses are input as the drive command signal Sc during a first period T1 from time t4 to time t5. In this case, the control circuit 2A determines that the "high-speed / forward rotation mode" has been specified as the operating mode, and transitions to a second period T2 from time t5, selecting correspondence relationship information 26H corresponding to the second rotation speed range R2 (high speed).

[0135] After time t5, when a PWM signal with a duty ratio of 50% is input as the drive command signal Sc, the control circuit 2A uses the method described above to set the target rotation speed to 5000 rpm based on the correspondence information 26H, and generates a drive control signal Sd so that the motor 40 rotates forward at a rotation speed of 5000 rpm.

[0136] Thereafter, at time t6, the input of the PWM signal as the drive command signal Sc stops, and at time t7 after a predetermined period T0 has elapsed, the control circuit 2A shifts to the first period T1 and stops the rotation of the motor 40.

[0137] 15, suppose three pulses are input as the drive command signal Sc during a first period T1 from time t7 to time t8. In this case, the control circuit 2A determines that the "low speed / reverse rotation mode" has been specified as the operating mode, and transitions to a second period T2 from time t8, selecting correspondence relationship information 26L corresponding to the first rotation speed range R1 (high speed).

[0138] After time t8, when a PWM signal with a duty ratio of 50% is input as the drive command signal Sc, the control circuit 2A sets the target rotation speed to 500 rpm based on the correspondence information 26L using the method described above, and generates a drive control signal Sd so that the motor 40 rotates in reverse at a rotation speed of 500 rpm.

[0139] Thereafter, at time t9, the input of the PWM signal as the drive command signal Sc stops, and at time t10 after a predetermined period T0 has elapsed, the control circuit 2A shifts to the first period T1 and stops the rotation of the motor 40.

[0140] 15, assume that four pulses are input as the drive command signal Sc during a first period T1 from time t10 to time t11. In this case, the control circuit 2A determines that the "high-speed reverse rotation mode" has been specified as the operating mode, and transitions to a second period T2 from time t11, selecting correspondence information 26H corresponding to the second rotation speed range R2 (high speed).

[0141] After time t11, when a PWM signal with a duty ratio of 50% is input as the drive command signal Sc, the control circuit 2A uses the method described above to set the target rotation speed to 5000 rpm based on the correspondence information 26H, and generates a drive control signal Sd so that the motor 40 rotates in reverse at a rotation speed of 5000 rpm.

[0142] As described above, in the motor drive control device 1A according to the second embodiment, an operating mode is set for each combination of a plurality of rotational speed ranges R1, R2 (low / high) and a rotation direction (forward / reverse), and each operating mode is associated with the number of pulses of the drive command signal Sc. In this way, by changing the number of pulses of the drive command signal Sc input during the first period T1, it is possible to change not only the rotational direction of the motor, but also the setting range (low / high) of the target rotational speed and the resolution.

[0143] In the second embodiment, the case where the "number of pulses" of the drive command signal Sc input during the first period T1 is analyzed to identify the operation mode has been described as an example, but this is not limiting. For example, the "pulse width" of the drive command signal Sc input during the first period T1 may be analyzed to identify the operation mode. That is, in the second embodiment, an operation mode may be associated with each pulse width of the drive command signal Sc, and the operation mode identification unit 20A may detect the pulse width of the drive command signal Sc input to the signal input terminal P3 during the first period T1 and identify the operation mode based on the detected pulse width.

[0144] FIG. 16 is a diagram showing another example of the relationship between the drive command signal Sc and the operating state of the fan 4 in the fan unit 6A according to the second embodiment.

[0145] The unit pulse width of the pulse input as the drive command signal Sc is set to W. Fig. 16 shows, as an example, a case in which the "low-speed, positive rotation mode" is assigned to the pulse width W, the "high-speed, positive rotation mode" is assigned to the pulse width (W x 2), the "low-speed, negative rotation mode" is assigned to the pulse width (W x 3), and the "high-speed, negative rotation mode" is assigned to the pulse width (W x 4).

[0146] As shown in Figure 16, suppose the pulse width of the drive command signal Sc input during the first period T1 from time t1 to time t2 is "W." In this case, the control circuit 2A determines that the "low-speed, forward rotation mode" has been specified as the operating mode. Also, suppose the pulse width of the drive command signal Sc input during the first period T1 from time t4 to time t5 is "W x 2." In this case, the control circuit 2A determines that the "high-speed, forward rotation mode" has been specified as the operating mode.

[0147] 16, suppose the pulse width of the drive command signal Sc input during the first period T1 from time t7 to time t8 is "W×3." In this case, the control circuit 2A determines that the "low-speed, negative rotation mode" has been specified as the operating mode. Also, suppose the pulse width of the drive command signal Sc input during the first period T1 from time t10 to time t11 is "W×4." In this case, the control circuit 2A determines that the "high-speed, negative rotation mode" has been specified as the operating mode.

[0148] In this way, in the motor drive control device 1A according to the second embodiment, the direction of rotation of the motor 40 can be easily switched by changing the width of the pulse input during the first period T1 using the pulse width of the drive command signal Sc.

[0149] <<Extending the Embodiments>> The invention made by the present inventor has been specifically described above based on the embodiments, but it goes without saying that the present invention is not limited thereto and can be modified in various ways without departing from the spirit of the invention.

[0150] For example, the operation modes shown in the above embodiment are merely examples, and various operation modes can be provided depending on the application of the fan units 6, 6 A. Furthermore, the specific values ​​of the number of pulses and pulse width shown in the above embodiment are merely examples, and any values ​​can be set as the number of pulses and pulse width associated with each operation mode.

[0151] In addition, in the above embodiment, the motor 40 is a three-phase brushless motor, but the type and number of phases of the motor 40 are not limited to this. For example, the motor 40 may be a single-phase brushless motor.

[0152] Furthermore, the above-described flowcharts are merely examples for explaining the operation, and are not intended to be limiting. That is, the steps shown in each diagram of the flowchart are specific examples, and the present invention is not limited to these flows. For example, the order of some processes may be changed, other processes may be inserted between processes, or some processes may be performed in parallel.

[0153] 1, 1A...motor drive control device, 2, 2A...control circuit, 3...drive circuit, 4...fan, 5...position detector, 6, 6A...fan unit, 20, 20A...operation mode identification unit, 21, 21A...target rotation speed identification unit, 22...signal generation unit, 23...rotation speed calculation unit, 24...rotation state signal generation unit, 25, 25A...correspondence information (number of pulses - operation mode), 26, 26L, 26H...correspondence information (duty ratio - rotation speed), 27, 27A...drive command signal analysis unit, 40...motor, 41...impeller, 49-52...signal line, Sc...drive command signal, Sd...drive control signal, Stv...target rotation speed information, Str...specified rotation direction information, Sv...rotation speed information, Sh...rotation position detection signal

Claims

1. A motor drive control device comprising: a signal input terminal for inputting a drive command signal that indicates the drive state of a motor; a control circuit that generates a drive control signal for controlling the rotation of the motor based on the drive command signal input to the signal input terminal; and a drive circuit that drives the motor based on the drive control signal, wherein periods after startup of the control circuit include a first period in which a designation of an operation mode of the motor is accepted, and a second period in which a designation of a target rotation speed that is a target value for the rotation speed of the motor is accepted and drive of the motor is controlled in accordance with the operation mode designated in the first period and the target rotation speed, wherein the control circuit includes: an operation mode specification unit that specifies the designated operation mode based on the aspect of the drive command signal input to the signal input terminal in the first period; a target rotation speed specification unit that specifies the target rotation speed based on the drive command signal input to the signal input terminal in the second period; and a signal generation unit that generates the drive control signal in the second period based on the operation mode specified by the operation mode specification unit and the target rotation speed specified by the target rotation speed specification unit.

2. A motor drive control device according to claim 1, wherein the first period is a period during which the designation of the target rotation speed is not accepted, but the designation of the operation mode is accepted.

3. A motor drive control device according to claim 1, wherein the drive command signal is a pulse signal, the operation mode is associated with each number of pulses of the drive command signal, and the operation mode identification unit detects the number of pulses of the drive command signal input to the signal input terminal during the first period, and identifies the operation mode based on the detected number of pulses.

4. A motor drive control device as described in claim 3, wherein the operation mode identification unit determines that a mode for rotating the motor in a first direction has been designated as the operation mode when the number of pulses detected during the first period is a first value, and determines that a mode for rotating the motor in a second direction opposite to the first direction has been designated as the operation mode when the number of pulses detected during the first period is a second value different from the first value.

5. A motor drive control device as claimed in claim 3, wherein the settable range of the motor rotational speed includes a first rotational speed range and a second rotational speed range different from the first rotational speed range, the target rotational speed within the first rotational speed range and the target rotational speed within the second rotational speed range are respectively assigned for each duty ratio of the drive command signal, and the operation mode identification unit determines that a mode in which the motor rotates in a first direction at a rotational speed within the first rotational speed range has been designated as the operation mode when the number of pulses detected in the first period is a first value, and determines that a mode in which the motor rotates in the first direction at a rotational speed within the second rotational speed range has been designated as the operation mode when the number of pulses detected in the first period is a second value different from the first value.

6. A motor drive control device as described in claim 5, wherein the operating mode identification unit determines that the operating mode is designated as a mode in which the motor rotates in a second direction opposite to the first direction at a rotational speed within the first rotational speed range when the number of pulses detected in the first period is a third value different from the first value and the second value, and determines that the operating mode is designated as a mode in which the motor rotates in the second direction at a rotational speed within the second rotational speed range when the number of pulses detected in the first period is a fourth value different from the first value, the second value, and the third value.

7. A motor drive control device according to claim 1, wherein the drive command signal is a pulse, the operation mode is associated with each pulse width of the drive command signal, and the operation mode identification unit detects the pulse width of the drive command signal input to the signal input terminal during the first period, and identifies the operation mode based on the detected pulse width.

8. A motor drive control device as described in claim 7, wherein the operation mode identification unit determines that a mode for rotating the motor in a first direction has been designated as the operation mode when the pulse width detected during the first period is a first value, and determines that a mode for rotating the motor in a second direction opposite to the first direction has been designated as the operation mode when the pulse width detected during the first period is a second value different from the first value.

9. A motor drive control device as claimed in claim 7, wherein the settable range of the motor rotational speed includes a first rotational speed range and a second rotational speed range different from the first rotational speed range, the target rotational speed within the first rotational speed range and the target rotational speed within the second rotational speed range are respectively assigned for each duty ratio of the drive command signal, and the operation mode identification unit determines that the operation mode has been designated as a mode in which the motor rotates in a first direction at a rotational speed within the first rotational speed range when the pulse width detected during the first period is a first value, and determines that the operation mode has been designated as a mode in which the motor rotates in the first direction at a rotational speed within the second rotational speed range when the pulse width detected during the first period is a second value different from the first value.

10. A motor drive control device as described in claim 9, wherein the operating mode identification unit determines that the operating mode is designated as a mode in which the motor rotates in a second direction opposite to the first direction at a rotational speed within the first rotational speed range when the pulse width detected during the first period is a third value different from the first value and the second value, and determines that the operating mode is designated as a mode in which the motor rotates in the second direction at a rotational speed within the second rotational speed range when the pulse width detected during the first period is a fourth value different from the first value, the second value, and the third value.

11. A fan unit comprising: the motor; an impeller connected to an output shaft of the motor; and the motor drive control device according to any one of claims 1 to 10.

12. A motor drive control method for controlling the rotation of a motor using a motor drive control device, comprising: a first step of generating a drive control signal for controlling the rotation of the motor based on a drive command signal that indicates the drive state of the motor; and a second step of driving the motor based on the drive control signal, wherein the motor drive control device includes, as periods after startup, a first period for accepting designation of an operation mode of the motor, and a second period for accepting designation of a target rotation speed that is a target value for the rotation speed of the motor, and controlling the drive of the motor in accordance with the operation mode designated in the first period and the target rotation speed, wherein the first step comprises: a third step of specifying the designated operation mode based on the form of the drive command signal input in the first period; and a fourth step of specifying the target rotation speed based on the drive command signal input in the second period, and generating the drive control signal based on the specified target rotation speed and the operation mode designated in the third step.

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