Motor driving device and motor driving method

Abstract

A motor drive device (1) is provided with: a target speed generation unit (10) that generates a target speed signal (St) indicating a target speed of a motor (2); an actual speed detection unit (14) that generates an actual speed signal (Sr) indicating the actual speed; and a drive unit (30) that drives the motor (2) so that the actual speed indicated by the actual speed signal (Sr) approaches the target speed indicated by the target speed signal (St), and the target speed generation unit (10) generates an input speed signal (Si) based on the input command and a provisional speed signal higher than the actual speed signal (Sr) at the time of startup. When the actual speed indicated by the actual speed signal (Sr) at the time of startup is higher than the speed indicated by the input speed signal, the provisional speed signal is output as the target speed signal.

Description

Technical Field

[0001] The present disclosure relates to a motor driving device and a motor driving method, and in particular to a driving method when a motor is started. Background Art

[0002] The driving device of the fan motor detects the rotation speed of the motor, and adjusts the air volume of the fan by increasing or decreasing the torque so as to make it reach the set target rotation speed. Before the fan motor is started, it is usually in a low-speed rotation state of inertial rotation after being stopped or stopped, and the torque is increased to the target rotation speed after starting. However, when the fan is idling due to external forces such as wind, especially if the fan motor is idling in the reverse rotation, the load on the fan motor becomes large and it is difficult to start. In addition, reverse rotation refers to rotation in the opposite direction to the rotation direction of the drive motor (i.e., forward rotation). Patent Documents 1 and 2 are disclosed as methods for starting a fan motor with forward rotation even if the fan is rotating in the reverse direction before starting.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 7-337080

[0006] Patent Document 2: Japanese Patent Application Publication No. 2005-137106 Summary of the invention

[0007] Problems to be solved by the invention

[0008] The prior art such as the above-mentioned Patent Document 1 and Patent Document 2 detects the rotation direction of idling in addition to the rotor position and the rotation speed at startup, and selects the driving method according to whether the idling is forward rotation or reverse rotation. Therefore, the driving circuit becomes complicated. On the other hand, if the rotation direction is not detected and the motor is driven only toward the target speed, when the speed is above the target value, there is a problem that the motor becomes uncontrollable and maintains the rotation state caused by the external force.

[0009] Therefore, the present disclosure proposes a motor driving device and a motor driving method that can reliably start a motor toward a target rotation speed of positive rotation with a simple structure.

[0010] Means for solving problems

[0011] In view of the above, a motor drive device involved in one embodiment of the present invention comprises: an actual speed detection unit, which generates an actual speed signal indicating the actual speed of the motor; a target speed generation unit, which generates a target speed signal indicating the target speed of the motor; and a drive unit, which drives the motor in a manner such that the actual speed indicated by the actual speed signal approaches the target speed indicated by the target speed signal, the target speed generation unit generating a first target speed signal indicating a speed based on an input instruction, and a second target speed signal indicating a speed higher than the actual speed when the motor drive device is started, and outputting the second target speed signal as the target speed signal when the actual speed indicated by the actual speed signal when the motor drive device is started is higher than the speed indicated by the first target speed signal.

[0012] In addition, a motor driving method involved in one embodiment of the present invention is a motor driving method based on a motor driving device, which includes: an actual speed detection step, generating an actual speed signal indicating the actual speed of the motor; a target speed generation step, generating a target speed signal indicating the target speed of the motor; and a driving step, driving the motor in such a manner that the actual speed indicated by the actual speed signal approaches the target speed indicated by the target speed signal, in which a first target speed signal indicating a speed based on an input instruction and a second target speed signal indicating a speed higher than the actual speed when the motor driving device is started are generated, and when the actual speed indicated by the actual speed signal when the motor driving device is started is higher than the speed indicated by the first target speed signal, the second target speed signal is output as the target speed signal.

[0013] Effects of the Invention

[0014] According to the present disclosure, a motor driving device and a motor driving method are realized that can reliably start a motor toward a target rotation speed for positive rotation with a simple structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 1 is a circuit diagram showing a motor drive device according to a first embodiment.

[0016] Figure 2 is a timing chart of normal startup of the motor drive device of the first embodiment ( Figure 2 (a)) Timing diagram of starting from high-speed positive rotation idling state ( Figure 2 (b)), and the timing diagram of starting from the idling state of high-speed reverse rotation ( Figure 2 (c)).

[0017] Figure 3It is a circuit configuration diagram of a motor drive device according to a second embodiment.

[0018] Figure 4 is a timing chart of normal startup of the motor drive device of the second embodiment ( Figure 4 (a)) Timing diagram of starting from high-speed positive rotation idling state ( Figure 4 (b)), and the timing diagram of starting from the idling state of high-speed reverse rotation ( Figure 4 (c)).

[0019] Figure 5 It is a circuit configuration diagram of a motor drive device according to a third embodiment.

[0020] Figure 6 is a timing chart of normal startup of the motor drive device of the third embodiment ( Figure 6 (a)) Timing diagram of starting from high-speed positive rotation idling state ( Figure 6 (b)), and the timing diagram of starting from the idling state of high-speed reverse rotation ( Figure 6 (c)).

[0021] Figure 7 It is a flowchart showing the operation of the motor driving device (that is, the motor driving method) according to the first to third embodiments. DETAILED DESCRIPTION

[0022] Hereinafter, the embodiments of the present disclosure will be described with reference to the accompanying drawings. In addition, the embodiments described below all represent a specific example of the present disclosure. Therefore, the numerical values, shapes, materials, constituent elements, and the configuration positions and connection forms of the constituent elements shown in the following embodiments are all examples, and their purpose is not to limit the present disclosure.

[0023] In addition, in each figure, the same reference numerals are given to substantially the same structure, and repeated descriptions are omitted or simplified. In addition, "A and B are connected" means that A and B are electrically connected, including not only the case where A and B are directly connected, but also the case where A and B are indirectly connected in a state where other circuit elements are interposed between A and B.

[0024] (First Embodiment)

[0025] Figure 1 FIG. 1 is a circuit diagram of a motor drive device 1 according to a first embodiment of the present disclosure. Figure 1In the embodiment, the motor driving device 1 is, for example, a driving device for a fan motor, and includes a target speed generating unit 10, a driving unit 30 (a speed comparing unit 11, a speed command generating unit 12, and an output unit 13), and an actual speed detecting unit 14. The motor driving device 1 performs a high-speed drive for positively rotating the motor 2 when the speed of the motor 2 is lower than the target speed based on an input speed signal Si indicating a target speed of the motor 2, thereby driving the motor 2 in such a manner that the speed of the motor 2 follows the target speed. The input speed signal Si is a signal converted in such a manner that an input command signal from the outside (e.g., a microcomputer, etc.) can be processed inside the motor driving device 1.

[0026] The motor 2 is provided with a position sensor 20 such as a Hall element, and the rotor position information of the motor 2 sent from the position sensor 20 is input to the actual speed detector 14 of the motor drive device 1. The actual speed detector 14 calculates the rotation speed of the motor 2 based on the rotor position information and outputs an actual speed signal Sr.

[0027] The target speed generating unit 10 receives an input speed signal Si and an actual speed signal Sr, and outputs a target speed signal St. The input speed signal Si is an example of a first target speed signal indicating a speed based on an input command. The actual speed signal Sr is a signal indicating an actual speed of the motor 2. The target speed signal St is a signal indicating a target speed of the motor 2. In the case of a normal startup in which the actual speed signal Sr is smaller than the input speed signal Si, the input speed signal Si is output from the target speed generating unit 10 as a target speed signal. In the case in which the actual speed signal Sr is larger than the input speed signal Si, a signal larger than the actual speed signal Sr (e.g., a 6.25% increase of the actual speed signal Sr) is output from the target speed generating unit 10 as a target speed signal St. That is, the target speed generating unit 10 has the following characteristics: it generates a first target speed signal indicating a speed based on an input command, and a second target speed signal indicating a speed higher than an actual speed at the startup of the motor drive device 1, and outputs the second target speed signal as a target speed signal when the actual speed indicated by the actual speed signal at the startup of the motor drive device 1 is higher than the speed indicated by the first target speed signal.

[0028] In addition, as described above, the input speed signal Si, the actual speed signal Sr, and the target speed signal St are all signals corresponding to the rotation speed of the motor (the rotation speed as an absolute value regardless of forward rotation / reverse rotation), and the magnitude (high or low) thereof indicates the high or low rotation speed. In addition, each signal may be a digital signal, an analog signal, or a pulse width modulated signal whose magnitude is indicated by a duty cycle, but in the description of the present disclosure, it is marked as an analog signal (positive voltage) in order to facilitate the imagination of the rotation speed.

[0029] That is, speed means rotation speed, which is synonymous with rotation speed. Rotation speed refers to the rotation speed of the motor 2 per unit time. With respect to the input speed signal Si, the actual speed signal Sr, and the target speed signal St, "large" or "high" means that the speed / rotation speed of the motor 2 represented by the signal is large / high.

[0030] The driving unit 30 is composed of a speed comparison unit 11 , a speed command generation unit 12 , and an output unit 13 .

[0031] The speed comparison unit 11 compares the target speed signal St and the actual speed signal Sr, and outputs a speed comparison result Cs. The speed comparison result Cs may be a signal indicating a speed error, but in the present disclosure, for simplicity, it is set to an H level when the actual speed signal Sr is greater than the target speed signal St, and is set to an L level when the actual speed signal Sr is less than the target speed signal St.

[0032] The speed command generating unit 12 receives the speed comparison result Cs from the speed comparing unit 11 and outputs a speed command signal Ss. The speed command signal Ss is, for example, a signal that increases when the actual speed signal Sr is lower than the target speed signal St (i.e., when the speed comparison result Cs indicates an L level), and decreases when the actual speed signal Sr is higher than the target speed signal St (i.e., when the speed comparison result Cs indicates an H level). The speed comparison result Cs is also fed back to the target speed generating unit 10. When the actual speed signal Sr reaches the target speed signal St and becomes an H level, the target speed generating unit 10 changes the increased target speed signal St and returns the signal output as the target speed signal St to the input speed signal Si.

[0033] The output unit 13 drives the motor 2 by outputting a pulse width modulation signal having a duty ratio corresponding to the speed command signal Ss.

[0034] The target speed generating unit 10 includes a comparison circuit 100, an edge detection circuit 101, a provisional speed setting circuit 102, an OR circuit 103, and a switching circuit 104. The comparison circuit 100 compares the input speed signal Si with the actual speed signal Sr, and outputs an H-level signal when the input speed signal Si is greater than the actual speed signal Sr. The edge detection circuit 101 receives the speed comparison result Cs from the speed comparison unit 11 as input, outputs an L-level signal at startup, and outputs an H-level signal when the speed comparison result Cs changes from the L-level to the H-level, and is fixed at the H-level and output in subsequent operations. The provisional speed setting circuit 102 receives the actual speed signal Sr from the actual speed detection unit 14 as input, and outputs a signal greater than the actual speed signal Sr (for example, 17 / 16 times the actual speed signal Sr, i.e., 6.25% increase) as a provisional speed signal Sz. The provisional speed signal Sz is an example of a second target speed signal indicating a speed higher than the actual speed at startup of the motor drive device 1. The provisional speed signal Sz output at the start-up is maintained, and is maintained even if the actual speed signal Sr changes thereafter. The maintenance period includes at least the period during which the switching circuit 104 described later selects the provisional speed signal Sz as the target speed signal St. The OR circuit 103 outputs the logical sum of the output of the comparison circuit 100 and the output of the edge detection circuit 101 as a switching signal. The switching circuit 104 selects the input speed signal Si as the target speed signal St to output when the switching signal output by the OR circuit 103 is at an H level, and selects the provisional speed signal Sz as the target speed signal St to output when the switching signal is at an L level.

[0035] use Figure 2 The operation of the motor drive device 1 according to the first embodiment configured as above at the time of startup will be described in more detail. Figure 2 is a timing chart of normal startup of the motor drive device 1 according to the first embodiment ( Figure 2 (a)) Timing diagram of starting from high-speed positive rotation idling state ( Figure 2 (b)), and the timing diagram of starting from the idling state of high-speed reverse rotation ( Figure 2 (c)). Figure 2 2 shows waveforms of signals of main parts of the motor drive device 1 .

[0036] Figure 2(a) is a timing diagram for a normal startup, i.e., the idling state at the startup of the motor drive device 1, which is independent of the rotation direction and in which the actual speed signal Sr is lower than the input speed signal Si. Before the startup before time t0, the power supply voltage is supplied to the motor drive device 1, but it is in a standby state with the input speed signal Si=0. Even if the actual speed signal Sr=0, as an initial state, the output of the comparison circuit 100 is set to an L level. In addition, the output of the edge detection circuit 101 is also set to an L level. Therefore, the output of the OR circuit 103 is an L level, and the switching circuit 104 selects the provisional speed signal Sz as the target speed signal St output. As described above, the provisional speed signal Sz is set by the provisional speed setting circuit 102 to a 6.25% increase (1 / 16) of the actual speed signal Sr.

[0037] Here, due to a small external force, the motor 2 is idling in a positive rotation mode, and the target speed signal St> the actual speed signal Sr> the input speed signal Si = 0. However, since it is in the standby state, the speed command generation unit 12 and the output unit 13 do not drive the motor 2 regardless of the speed comparison result Cs.

[0038] When the input speed signal Si rises and starts at time t0, since the input speed signal Si> the actual speed signal Sr, the output of the comparison circuit 100 becomes H level. The switching circuit 104 to which the H level switching signal is input via the OR circuit 103 selects the input speed signal Si as the target speed signal St output. In the speed comparison unit 11, since the target speed signal St> the actual speed signal Sr, the speed comparison result Cs becomes L level, and the speed command signal Ss from the speed command generation unit 12 that has started the action rises, and the speed of the motor 2 increases in the forward rotation direction (increases after temporarily stopping during reverse rotation). The actual speed signal Sr rises as the speed increases, but the target speed signal St, i.e., the provisional speed signal Sz, is maintained and does not change at the time of startup.

[0039] When the actual speed signal Sr reaches the target speed signal St at time t1, the speed comparison result Cs becomes H level, and the speed command signal Ss stops rising. In the target speed generating unit 10, the output of the comparison circuit 100 becomes L level, but the output of the edge detection circuit 101 that detects the speed comparison result Cs rising to H level becomes H level, so the OR circuit 103 is maintained at H level, and the switching circuit 104 continues to output the input speed signal Si as the target speed signal St. After that, the speed of the motor 2 is maintained near the target speed. Strictly speaking, since the target speed is slightly increased or decreased, the output of the comparison circuit 100 and the speed comparison result Cs are unstable (indicated by oblique lines in the figure), but since the output of the edge detection circuit 101 is fixed at H level, the switching signal output by the OR circuit 103 is also fixed at H level, and the switching circuit 104 maintains the input speed signal Si as the target speed signal St.

[0040] Figure 2 (b) is a timing diagram when starting from an idling state of high-speed positive rotation, that is, the idling state at the time of starting the motor drive device 1 is positive rotation and the actual speed signal Sr is higher than the input speed signal Si. Before starting before time t0, except that the level of the actual speed signal Sr is high, Figure 2 The same as the normal start in (a). At time t0, the input speed signal Si rises and starts, but since the actual speed signal Sr>input speed signal Si, the output of the comparison circuit 100 is L level. Since the output of the edge detection circuit 101 is also L level, the switching signal output by the OR circuit 103 is L level, and the switching circuit 104 selects the provisional speed signal Sz as the target speed signal St output. The provisional speed signal Sz is set by the provisional speed setting circuit 102 to a 6.25% increase (1 / 16) of the actual speed signal Sr. Since the target speed signal St>actual speed signal Sr, the speed comparison result Cs becomes L level, the speed command signal Ss rises, and the rotation speed of the motor 2 increases in the positive rotation direction. The situation that the provisional speed signal Sz, that is, the target speed signal St, maintained at startup does not change is the same as Figure 2 Same as (a).

[0041] When the actual speed signal Sr reaches the target speed signal St at time t1, the speed comparison result Cs output by the speed comparison unit 11 becomes H level, and the speed command signal Ss output by the speed command generation unit 12 stops rising. In the target speed generation unit 10, the output of the edge detection circuit 101 is inverted and becomes H level, so the switching signal output by the OR circuit 103 also becomes H level, and the switching circuit 104 changes the signal output as the target speed signal St to the input speed signal Si. At this time, the actual speed signal Sr>target speed signal St=input speed signal Si, the output of the comparison circuit 100 becomes L level, but the output of the edge detection circuit 101 maintains H level, so the target speed signal St output by the switching circuit 104 maintains the input speed signal Si. Since the actual speed signal Sr>target speed signal St, the speed command signal Ss decreases, and the rotation speed of the motor 2 decreases to the rotation speed caused by the external force.

[0042] Figure 2 (c) is a timing diagram for starting from an idling state with high-speed reverse rotation, that is, when the idling at the start of the motor drive device 1 is reverse rotation and the actual speed signal Sr is higher than the input speed signal Si. Figure 2 The same as (b) in FIG. 1 . When the input speed signal Si rises and starts at time t0, since the actual speed signal Sr> the input speed signal Si, the target speed signal St becomes a provisional speed signal Sz higher than the actual speed signal Sr. Since the target speed signal St> the actual speed signal Sr, the speed comparison result Cs output by the speed comparison unit 11 becomes an L level. Since the speed command signal Ss output by the speed command generation unit 12 rises, the output unit 13 drives the motor 2 in a manner that increases the rotation speed in the positive rotation direction. That is, if it is in the reverse rotation state, the rotation speed decreases.

[0043] When the actual speed signal Sr after the decrease is lower than the input speed signal Si at time t1, in the target speed generating unit 10, the output of the comparison circuit 100 is inverted to the H level, the switching signal output by the OR circuit 103 also becomes the H level, and the switching circuit 104 changes the signal output as the target speed signal St to the input speed signal Si. The rotation speed of the motor 2 which is decreased by the reverse rotation eventually becomes zero, and increases by turning to the forward rotation.

[0044] When the actual speed signal Sr reaches the target speed signal St at time t2, the speed comparison result Cs becomes H level, and the output of the comparison circuit 100 becomes L level. Figure 2The same action as in (a) is performed, and the speed of the motor 2 is maintained near the target speed. The output of the comparison circuit 100 and the speed comparison result Cs are unstable, but the output of the edge detection circuit 101 is fixed to the H level, the switching signal is also fixed to the H level, and the switching circuit 104 maintains the input speed signal Si as the target speed signal St.

[0045] As described above, according to the motor drive device 1 of the first embodiment, even if the motor 2 rotates in the reverse direction to a speed exceeding the target speed due to external force before starting, the motor 2 can be forcibly driven in the forward direction and started because the target speed is temporarily set higher than the actual speed.

[0046] (Second Embodiment)

[0047] The motor drive device disclosed in the present invention does not need to be provided with a detection circuit for the rotation direction. Even if it can be started from reverse rotation above the target speed, the rotation direction can be simply detected. When the target speed is temporarily increased, the actual speed increases if the vehicle is idling in forward rotation, and decreases if the vehicle is idling in reverse rotation, so the rotation direction can be simply detected. The motor drive device of the second embodiment has a function of simply detecting the rotation direction of idling at startup by utilizing this phenomenon.

[0048] Figure 3 FIG. 2 shows a circuit configuration of a motor drive device 1A according to a second embodiment. Figure 3 In Figure 1 The same components as the motor drive device 1 are denoted by the same reference numerals, and the description thereof will be omitted. Figure 1 The differences are: the target speed generating unit 10A has a changed internal structure; the speed comparison result Cs from the speed comparing unit 11 is not fed back; the edge detecting circuit 101 is replaced by the edge detecting circuit 101A connected between the output of the OR circuit 103A and the switching circuit 104; and the differential circuit 105 is added. The differential circuit 105 simply detects the rotation direction of the motor 2 by detecting the slope of the actual speed signal Sr, and outputs an H level when the actual speed signal Sr rises, and outputs an L level when the actual speed signal Sr falls.

[0049] use Figure 4 The operation at the time of startup of the motor drive device 1A according to the second embodiment configured as above will be described in more detail. Figure 4 is a timing chart of normal startup of the motor drive device 1A according to the second embodiment ( Figure 4 (a)) Timing diagram of starting from high-speed positive rotation idling state ( Figure 4 (b)), and the timing diagram of starting from the idling state of high-speed reverse rotation ( Figure 4 (c)). Figure 42 shows waveforms of signals of main parts of the motor drive device 1A.

[0050] Figure 4 (a) is a timing diagram for a normal startup, i.e., the idling state at the startup of the motor drive device 1A, regardless of the rotation direction, and the actual speed signal Sr is lower than the input speed signal Si. Before the startup before time t0, the motor drive device 1A is supplied with a power supply voltage, but is in a standby state with the input speed signal Si=0. Even if the actual speed signal Sr=0, as an initial state, the output of the comparison circuit 100 is set to an L level. In addition, the output of the edge detection circuit 101A and the output of the differential circuit 105 are also set to an L level. Therefore, the output of the OR circuit 103A becomes an L level, and the switching circuit 104 selects the provisional speed signal Sz as the target speed signal St output. As described above, the provisional speed signal Sz is set by the provisional speed setting circuit 102 to a 6.25% increase (1 / 16) of the actual speed signal Sr.

[0051] Here, due to a small external force, the motor 2 is idling in positive rotation, and the target speed signal St> the actual speed signal Sr> the input speed signal Si = 0. However, since it is in the standby state, the speed command generation unit 12 and the output unit 13 do not drive the motor 2 regardless of the speed comparison result Cs.

[0052] When the input speed signal Si rises and starts at time t0, since the input speed signal Si>actual speed signal Sr, the output of the comparison circuit 100 becomes H level. The output of the OR circuit 103A also becomes H level, and the output of the edge detection circuit 101A, that is, the switching signal input to the switching circuit 104 is fixed to H level. After that, the switching circuit 104 selects the input speed signal Si as the target speed signal St output, and the rotation speed of the motor 2 increases in the positive rotation direction (temporarily stops and then increases during reverse rotation). During the increase in rotation speed, the actual speed signal Sr also rises, so the output of the differential circuit 105 is H level. In addition, the temporary speed signal Sz maintained at startup, that is, the target speed signal St, does not change, which is the same as Figure 2 Same as (a).

[0053] After the actual speed signal Sr reaches the target speed signal St at time t1, the speed of the motor 2 is maintained near the target speed. Strictly speaking, since the target speed is slightly increased or decreased, the output of the comparison circuit 100, the output of the differentiation circuit 105, and the speed comparison result Cs are unstable, but the output of the edge detection circuit 101A, i.e., the switching signal, is also fixed to the H level, so the switching circuit 104 maintains the input speed signal Si as the target speed signal St.

[0054] Figure 4(b) is a timing diagram of starting from a high-speed positive rotation idling state, that is, when the idling at the start of the motor drive device 1A is positive rotation and the actual speed signal Sr is higher than the input speed signal Si. Before starting before time t0, except that the level of the actual speed signal Sr is high, Figure 4 The same as the normal start in (a). When the input speed signal Si rises and starts at time t0, since the actual speed signal Sr> input speed signal Si, the output of the comparison circuit 100 is L level. The output of the differential circuit 105 to which the actual speed signal Sr that has not changed is input is also L level, so the switching signal output by the OR circuit 103A is L level, and the switching signal input via the edge detection circuit 101A is L level, and the switching circuit 104 selects the temporary speed signal Sz as the target speed signal St output. As described in the first embodiment, the temporary speed signal Sz is set by the temporary speed setting circuit 102 to a 6.25% increase (1 / 16) of the actual speed signal Sr before starting. Since the target speed signal St> actual speed signal Sr, the rotation speed of the motor 2 increases in the positive rotation direction.

[0055] When the output of the differential circuit 105 that detects the rise of the actual speed signal Sr becomes H level at time t0, the output of the OR circuit 103A becomes H level, and the output of the edge detection circuit 101A, that is, the switching signal, is also fixed to H level, so the switching circuit 104 selects the input speed signal Si as the target speed signal St output. The actual speed signal Sr is already higher than the input speed signal Si, that is, the target speed signal St, so the speed comparison result Cs becomes H level, the speed command signal Ss stops rising, the increased speed decreases, and the actual speed signal Sr also turns to decrease. In the target speed generating unit 10A, the output of the comparison circuit 100 and the output of the differential circuit 105 both become L level, so the output of the OR circuit 103A also becomes L level, but the output of the edge detection circuit 101A maintains H level, so the target speed signal St output by the switching circuit 104 maintains the input speed signal Si. Since the actual speed signal Sr> the target speed signal St, the speed command signal Ss decreases, and the speed of the motor 2 decreases to the speed caused by the external force.

[0056] Figure 4 (c) is a timing chart of starting from an idling state with high-speed reverse rotation, that is, when the idling at the start of the motor drive device 1A is reverse rotation and the actual speed signal Sr is higher than the input speed signal Si. Figure 4The same as (b) in FIG. 1 . When the input speed signal Si rises and starts at time t0, since the actual speed signal Sr> the input speed signal Si, the target speed signal St becomes a provisional speed signal Sz higher than the actual speed signal Sr. Since the target speed signal St> the actual speed signal Sr, the speed comparison result Cs output by the speed comparison unit 11 becomes an L level. Since the speed command signal Ss output by the speed command generation unit 12 rises, the output unit 13 drives in a manner that increases the rotation speed of the motor 2 in the positive rotation direction. That is, if it is in the reverse rotation state, the rotation speed decreases, and the output of the differential circuit 105 becomes an L level.

[0057] When the reduced actual speed signal Sr is lower than the input speed signal Si at time t1, in the target speed generating unit 10A, the output of the comparison circuit 100 is inverted to the H level, the switching signal output by the OR circuit 103A also becomes the H level, the output of the edge detection circuit 101A also becomes the H level, and the switching circuit 104 changes the signal output as the target speed signal St to the input speed signal Si. The rotation speed of the motor 2 reduced by the reverse rotation finally becomes zero at time t2, and increases by turning to the forward rotation, and the output of the differential circuit 105 becomes the H level.

[0058] When the actual speed signal Sr reaches the target speed signal St at time t3, the speed comparison result Cs becomes H level, and the output of the comparison circuit 100 becomes L level. Figure 4 The same action as in (a) is performed, and the speed of the motor 2 is maintained near the target speed. The output of the comparison circuit 100, the output of the differential circuit 105, and the speed comparison result Cs are unstable, but the output of the edge detection circuit 101A, i.e., the switching signal, is fixed to the H level, and the switching circuit 104 maintains the input speed signal Si as the target speed signal St.

[0059] As described above, according to the motor drive device 1A of the second embodiment, even if the motor 2 rotates in reverse to a speed higher than the target speed due to external force before starting, the target speed is set to be temporarily greater than the actual speed, so the motor 2 can be forced to be driven in the positive rotation direction and started. In addition, after temporarily increasing the target speed, if the motor rotates in the positive direction, the actual speed increases, and if the motor rotates in the reverse direction, the actual speed decreases, so that the rotation direction of the motor 2 can be determined. In the case of positive rotation and high speed, the input speed signal Si is returned as a signal output as the target speed signal St at the moment of determining the positive rotation, so that the increase in the speed can be suppressed.

[0060] (Third Embodiment)

[0061] In the first and second embodiments, in order to prevent the target speed from changing during the stable operation after starting, an edge detection circuit is used to limit the start-up. However, in order to prevent malfunction after starting, a predetermined time from starting can be set as the start-up time, and the setting and change of the target speed can be limited to the start-up time. In other words, by fixing the target speed signal St to the input speed signal Si after the start-up time, the stable operation can be stabilized without the need for an edge detection circuit or any latch circuit. The motor drive device of the third embodiment has the function of stabilizing the stable operation by setting the start-up time without the need for an edge detection circuit or any latch circuit.

[0062] Figure 5 FIG. 2 shows a circuit configuration of a motor drive device 1B according to a third embodiment. Figure 5 In Figure 1 The same components as the motor drive device 1 are denoted by the same reference numerals, and the description thereof will be omitted. Figure 1 The differences are as follows: the target speed generating unit 10B has a changed internal structure; the speed comparison result Cs from the speed comparing unit 11 is not fed back; there is no edge detecting circuit 101; a comparing circuit 106 for comparing the input speed signal Si with the specified value Sx, a delay circuit 107 for delaying the output of the comparing circuit 106, and an AND circuit 108 for outputting the logical product of the output of the comparing circuit 106 and the output of the delay circuit 107 are provided; an OR circuit 103B is provided instead of the OR circuit 103, and the output of the comparing circuit 100 and the output of the AND circuit 108 are input to the OR circuit 103B, and the switching signal is output to the switching circuit 104. In addition, the output of the comparing circuit 106 is output from the target speed generating unit 10B as the action signal Sy, and is input as the enable signal of the speed instruction generating unit 12 and the output unit 13.

[0063] The comparison circuit 106 outputs an H level when the input speed signal Si is greater than a predetermined value Sx. The predetermined value Sx is set to be lower than the normal level of the input speed signal Si generated after the operation, and the delay time of the delay circuit 107 is set to be equivalent to the start time of the motor 2. That is, the period when the output of the comparison circuit 106, i.e., the operation signal Sy, is at an H level becomes the operation period of the motor 2, and the period when the output of the AND circuit 108 is at an L level becomes the stop and start time of the motor 2.

[0064] use Figure 6 The operation at the time of startup of the motor drive device 1B according to the third embodiment configured as above will be described in more detail. Figure 6 is a timing chart of normal startup of the motor drive device 1B according to the third embodiment ( Figure 6 (a)) Timing diagram of starting from high-speed positive rotation idling state ( Figure 6(b)) and the timing diagram of starting from the idling state of high-speed reverse rotation ( Figure 6 (c)). Figure 6 2 shows waveforms of signals of main parts of the motor drive device 1B.

[0065] Figure 6 (a) is a timing diagram for normal startup, that is, the idling state at the startup of the motor drive device 1B is independent of the rotation direction and the actual speed signal Sr is lower than the input speed signal Si. Before the startup before time t0, it is a standby state with the input speed signal Si=0, and the output of the comparison circuit 100 is set to L level. In addition, the action signal Sy, which is the output of the comparison circuit 106, is also L level, so the output of the OR circuit 103B becomes L level, and the switching circuit 104 selects the provisional speed signal Sz as the target speed signal St output. Here, due to a small external force, the motor 2 is idling in the positive rotation, and the target speed signal St>actual speed signal Sr>input speed signal Si=0. Since the action signal Sy is L level, the speed instruction generation unit 12 and the output unit 13 are both in the standby state, and no signal for driving the motor 2 is output.

[0066] When the input speed signal Si rises and starts at time t0, the input speed signal Si>actual speed signal Sr becomes, and the output of the comparison circuit 100 becomes H level. The output of the OR circuit 103B also becomes H level, and the switching circuit 104 selects the input speed signal Si as the target speed signal St for output. Since the action signal Sy becomes H level, the speed command generation unit 12 and the output unit 13 both start to operate, and the speed comparison result Cs of the speed comparison unit 11, which is L level, of the target speed signal St>actual speed signal Sr, increases the rotation speed of the motor 2 in the forward rotation direction (temporarily stops and then increases in the reverse rotation).

[0067] At time t1, the output of the AND circuit 108 becomes H level, and at time t2, after the actual speed signal Sr reaches the target speed signal St, the speed of the motor 2 is maintained near the target speed. Strictly speaking, since the target speed is slightly increased or decreased, the output of the comparison circuit 100 and the speed comparison result Cs are unstable, but since the output of the AND circuit 108 is H level, the switching signal is also fixed to H level, and the switching circuit 104 maintains the input speed signal Si as the target speed signal St.

[0068] Figure 6 (b) is a timing diagram of the case where the motor drive device 1B is started from the idling state of high-speed positive rotation, that is, the idling state at the time of starting is positive rotation and the actual speed signal Sr is higher than the input speed signal Si. Before starting before time t0, except that the level of the actual speed signal Sr is high, Figure 6The same as the normal start in (a). When the input speed signal Si rises at time t0 and starts, since the actual speed signal Sr> input speed signal Si, the output of the comparison circuit 100 is L level. Since the output of the AND circuit 108 is also L level, the switching signal output by the OR circuit 103B is L level, and the switching circuit 104 selects the provisional speed signal Sz as the target speed signal St output. The provisional speed signal Sz is a value of 6.25% increase of the actual speed signal Sr at the time of startup. The target speed signal St> actual speed signal Sr, so the speed comparison result Cs output by the speed comparison unit 11 becomes L level. Since the speed command signal Ss output by the speed command generation unit 12 rises, the output unit 13 is driven in a manner that increases the rotation speed of the motor 2 in the positive rotation direction. Therefore, the rotation speed of the motor 2 further increases in the positive rotation direction.

[0069] When the output of AND circuit 108 becomes H level at time t1, the switching signal is fixed to H level, and the target speed signal St is fixed to the input speed signal Si. Since the actual speed signal Sr> the target speed signal St, the speed command signal Ss decreases, and the speed of the motor 2 decreases to the speed caused by the external force.

[0070] Figure 6 (c) is a timing chart for starting from an idling state with high-speed reverse rotation, that is, when the idling at the start of the motor drive device 1B is reverse rotation and the actual speed signal Sr is higher than the input speed signal Si. Figure 6 The same as (b) in FIG. 1 . When the input speed signal Si rises at time t0 and starts, since the actual speed signal Sr> the input speed signal Si, the target speed signal St becomes a provisional speed signal Sz higher than the actual speed signal Sr at the time of starting. Since the target speed signal St> the actual speed signal Sr, the speed comparison result Cs output by the speed comparison unit 11 becomes an L level. Since the speed command signal Ss output by the speed command generation unit 12 rises, the output unit 13 drives in a manner that increases the rotation speed of the motor 2 in the positive rotation direction. That is, since it is in the reverse rotation state, the rotation speed decreases. When the reduced actual speed signal Sr is lower than the input speed signal Si, in the target speed generation unit 10B, the output of the comparison circuit 100 is reversed to an H level, the switching signal output by the OR circuit 103B also becomes an H level, and the switching circuit 104 changes the signal output as the target speed signal St to the input speed signal Si. The time t1 at which the output of the AND circuit 108 becomes an H level can be set after this. The rotation speed of the motor 2 reduced by the reverse rotation eventually becomes zero, and turns to positive rotation and increases.

[0071] When the actual speed signal Sr reaches the target speed signal St at time t2, the speed comparison result Cs becomes H level, and the output of the comparison circuit 100 becomes L level. Figure 6 The same operation as in (a) is performed, and the rotation speed of the motor 2 is maintained near the target rotation speed. The output of the comparison circuit 100 and the speed comparison result Cs are unstable, but the output of the AND circuit 108 is fixed at the H level, and the switching circuit 104 maintains the input speed signal Si as the target speed signal St.

[0072] As described above, according to the motor drive device 1B of the third embodiment, even if the motor 2 rotates in the reverse direction to a speed higher than the target speed due to external force before starting, the target speed is temporarily set to be higher than the actual speed, so that the motor 2 can be forced to be driven in the forward rotation direction and started. Furthermore, the starting time is appropriately set, and when it is from starting to the starting time, the target speed signal St is fixed to the input speed signal Si during the subsequent operation time, so that the stable operation can be stabilized without the need for an edge detection circuit or some latch circuits.

[0073] (Motor drive method)

[0074] The motor drive devices (especially the target speed generating unit and the driving unit) of the first to third embodiments described above can be implemented not only in hardware by a dedicated electronic circuit, but also in software by a microcomputer composed of a memory storing programs, a processor executing programs, and an input / output circuit (including an A / D converter, a D / A converter, and a digital input / output circuit). In order to make this clear, the operation of the motor drive devices of the first to third embodiments described above, that is, the motor driving method, will be described.

[0075] Figure 7 The flowchart is a flowchart showing the operation of the motor drive device (i.e., the motor drive method) of the first to third embodiments. In the following, for the sake of convenience, the operation of the motor drive device 1 of the first embodiment is described as an object, but the operation described below is also the same for the motor drive device 1A of the second embodiment and the motor drive device 1B of the third embodiment.

[0076] When the motor drive device 1 is started, first, the actual speed detection unit 14 generates an actual speed signal Sr indicating the actual speed of the motor 2 (actual speed detection step S10). Next, the target speed generation unit 10 generates a target speed signal St indicating the target speed of the motor 2 (target speed generation step S11). Finally, the drive unit 30 drives the motor 2 in such a way that the actual speed indicated by the actual speed signal Sr approaches the target speed indicated by the target speed signal St (driving step S12).

[0077] Here, in the target speed generating step S11, the target speed generating unit 10 generates an input speed signal Si (S11a), which is an example of a first target speed signal indicating a speed based on an input command, by acquiring an input command from the outside, and generates a provisional speed signal Sz (S11b), which is an example of a second target speed signal indicating a speed higher than an actual speed when the motor drive device 1 is started, through the provisional speed setting circuit 102. Then, the target speed generating unit 10 determines whether the actual speed indicated by the actual speed signal Sr when the motor drive device 1 is started is higher than the speed indicated by the input speed signal Si (S11c) by means of the comparison circuit 100, etc. If the actual speed is higher than the speed indicated by the input speed signal Si ("Yes" in S11c), the provisional speed signal Sz is output as the target speed signal St (S11d), and if the actual speed is not higher than the speed indicated by the input speed signal Si ("No" in S11c), the input speed signal Si is output as the target speed signal St (S11e).

[0078] With this motor driving method, even if the motor 2 rotates in the reverse direction to a speed exceeding the target speed due to external force before starting, the motor 2 can be forcibly driven in the forward direction and started because the target speed is temporarily set higher than the actual speed.

[0079] As described above, the motor drive device 1 of the present disclosure includes: an actual speed detection unit 14, which generates an actual speed signal Sr indicating the actual speed of the motor 2; a target speed generation unit 10, etc., which generates a target speed signal St indicating the target speed of the motor 2; and a drive unit 30, which drives the motor 2 in a manner that makes the actual speed indicated by the actual speed signal Sr approach the target speed indicated by the target speed signal St. The target speed generation unit 10, etc. generates an input speed signal Si as an example of a first target speed signal indicating a speed based on an input instruction, and a provisional speed signal Sz as an example of a second target speed signal indicating a speed higher than the actual speed when the motor drive device 1 is started. When the actual speed indicated by the actual speed signal Sr when the motor drive device 1 is started is higher than the speed indicated by the input speed signal Si, the provisional speed signal Sz is output as the target speed signal St.

[0080] Thus, when the actual speed represented by the actual speed signal Sr when the motor drive device 1 or the like is started is higher than the speed represented by the input speed signal Si, the provisional speed signal Sz is output as the target speed signal St representing a speed higher than the actual speed when the motor drive device 1 or the like is started. As a result, even if the motor 2 rotates in the reverse direction to a speed higher than the target speed due to external force or the like before starting, the motor 2 can be forcibly driven in the forward rotation direction and started because the target speed is temporarily set to be higher than the actual speed. Therefore, a motor drive device capable of starting a motor with a simple structure is realized.

[0081] Here, when the target speed generating unit 10 outputs the provisional speed signal Sz as the target speed signal St, if the actual speed represented by the actual speed signal Sr reaches the speed represented by the provisional speed signal Sz, the input speed signal Si is output as the target speed signal St. Thus, after the actual speed reaches the speed represented by the provisional speed signal Sz, the speed represented by the input speed signal Si is used as the target speed, and normal drive control is performed.

[0082] Furthermore, when the target speed generating unit 10 outputs the provisional speed signal Sz as the target speed signal St, if the actual speed indicated by the actual speed signal Sr is lower than the speed indicated by the input speed signal Si, the input speed signal Si is output as the target speed signal St. Thus, when the motor 2 rotates reversely to a speed higher than the target speed due to an external force or the like before starting, if the actual speed is lower than the speed indicated by the input speed signal Si, the input speed signal Si is output as the target speed signal St, and then the speed indicated by the input speed signal Si is used as the target speed to perform normal drive control.

[0083] In addition, in the second embodiment, the target speed generating unit 10A has a differential circuit 105 for detecting the rise and fall of the actual speed represented by the actual speed signal Sr. When the target speed generating unit 10A outputs the provisional speed signal Sz as the target speed signal St, if the differential circuit 105 detects the rise of the actual speed, the input speed signal Si is output as the target speed signal St. Thus, the forward rotation and reverse rotation of the motor 2 can be simply detected with a simple circuit, and even if the motor 2 is rotated forward to a speed higher than the target speed due to an external force before starting, since the target speed is set to be temporarily higher than the actual speed, the motor 2 can be forcibly driven in the forward rotation direction and started.

[0084] In addition, in the second embodiment, when the target speed generating unit 10A outputs the provisional speed signal Sz as the target speed signal St, if the differential circuit 105 detects a decrease in the actual speed, it is determined that the motor 2 is rotating in the reverse direction. Thus, the forward rotation and reverse rotation of the motor 2 can be simply detected with a simple circuit, and even if the motor 2 rotates in the reverse direction to a speed exceeding the target speed due to an external force before starting, the motor 2 can be forcibly driven in the forward rotation direction and started.

[0085] Furthermore, in the third embodiment, after a predetermined period of time has elapsed since the input speed signal Si rises, the target speed generating unit 10B outputs the input speed signal Si as the target speed signal St. Thus, when the predetermined period of time has elapsed since the start, the target speed signal St is fixed to the input speed signal Si during the subsequent operation time, so that the steady operation can be stabilized without the need for an edge detection circuit or some latch circuit as in the first embodiment.

[0086] In addition, the motor driving method disclosed in the present invention is a motor driving method based on a motor driving device 1, etc., which includes: an actual speed detection step S10, generating an actual speed signal Sr indicating the actual speed of the motor 2; a target speed generation step S11, generating a target speed signal St indicating the target speed of the motor 2; and a driving step S12, driving the motor 2 in a manner that makes the actual speed indicated by the actual speed signal Sr close to the target speed indicated by the target speed signal St. In the target speed generation step S11, an input speed signal Si as an example of a first target speed signal indicating a speed based on an input instruction and a provisional speed signal Sz as an example of a second target speed signal indicating a speed higher than the actual speed when the motor driving device 1 is started are generated (S11a and S11b). When the actual speed indicated by the actual speed signal Sr when the motor driving device 1 is started is higher than the speed indicated by the input speed signal Si (S11c: yes), the provisional speed signal Sz is output as the target speed signal St (S11d).

[0087] Thus, when the actual speed represented by the actual speed signal Sr when the motor drive device 1 or the like is started is higher than the speed represented by the input speed signal Si, the provisional speed signal Sz is output as the target speed signal St representing a speed higher than the actual speed when the motor drive device 1 or the like is started. As a result, even if the motor 2 rotates in the reverse direction to a speed higher than the target speed due to external force or the like before starting, the motor 2 can be forcibly driven in the forward rotation direction and started because the target speed is temporarily set to be higher than the actual speed. Therefore, a motor driving method capable of starting a motor with a simple structure is realized.

[0088] The motor driving method of the present disclosure can also be implemented as a program for causing a computer to execute the actual speed detection step S10 , the target speed generation step S11 , and the driving step S12 included in the motor driving method, or as a computer-readable recording medium such as a DVD recording the program.

[0089] The motor drive device and the motor drive method of the present disclosure are described above based on the first to third embodiments, but the present disclosure is not limited to these embodiments. As long as it does not deviate from the main purpose of the present disclosure, the various deformations that can be thought of by those skilled in the art to these embodiments, and other methods constructed by combining some of the constituent elements in these embodiments are also included in the scope of the present disclosure.

[0090] For example, in the above-mentioned embodiments, the comparator circuit 100 is used to detect the start from the rise of the input speed signal, but the present disclosure is not limited to this structure. The rise may also be detected by a structure in which a start signal or the like is input separately from the outside of the input command signal.

[0091] In addition, in each of the above embodiments, a position detection signal based on a Hall element is used to calculate the rotation speed of the motor 2, but the present disclosure is not limited to this structure. Even in sensorless control without using a position sensor such as a Hall element, as long as the rotation speed can be detected or calculated, it will suffice. For example, as a position detection in sensorless control, a method of detecting the zero crossing of the motor winding voltage is known, and the rotation speed can be calculated by counting the zero crossings within a specified time.

[0092] In the first embodiment and the like, a signal indicating a speed 17 / 16 times the speed indicated by the actual speed signal Sr is used as the provisional speed signal Sz, but the present invention is not limited thereto and any signal may be used as long as it indicates a speed greater than the speed indicated by the actual speed signal Sr.

[0093] In the third embodiment, the predetermined value Sx input to one input terminal of the comparison circuit 106 and the delay amount in the delay circuit 107 may be fixed values ​​or variable values ​​that can be adjusted from the outside.

[0094] Furthermore, in each of the above-described embodiments, the input speed signal Si is determined by an input command signal from the outside, but may be a fixed value or a value determined by the motor drive device itself depending on the purpose of the motor drive device.

[0095] Industrial Applicability

[0096] The motor driving device disclosed herein can be used as a motor driving device capable of starting a motor with a simple structure, for example, as a driving device for a fan motor or a driving device for a motor that may idle due to external forces such as wind.

[0097] Reference numerals

[0098] 1, 1A, 1B motor driving device; 10, 10A, 10B target speed generating unit; 100, 106 comparison circuit; 101, 101A edge detection circuit; 102 provisional speed setting circuit; 103, 103A, 103B OR circuit; 104 switching circuit; 105 differential circuit; 107 delay circuit; 108 AND circuit; 11 speed comparison unit; 12 speed instruction generating unit; 13 output unit; 14 actual speed detecting unit; 2 motor; 20 position sensor; 30 driving unit.

Claims

1. A motor drive device, have: an actual speed detection unit that generates an actual speed signal indicating an actual speed of the motor; a target speed generating unit that generates a target speed signal indicating a target speed of the motor; and a driving unit driving the motor in such a manner that an actual speed represented by the actual speed signal approaches a target speed represented by the target speed signal, The target speed generating unit generates a first target speed signal indicating a speed based on an input instruction, and a second target speed signal indicating a speed higher than the actual speed when the motor drive device is started, and outputs the second target speed signal as the target speed signal when the actual speed indicated by the actual speed signal when the motor drive device is started is higher than the speed indicated by the first target speed signal.

2. The motor drive device according to claim 1, The target speed generating unit outputs the first target speed signal as the target speed signal when the actual speed indicated by the actual speed signal reaches the speed indicated by the second target speed signal when outputting the second target speed signal as the target speed signal.

3. The motor drive device according to claim 1, When the target speed generating unit outputs the second target speed signal as the target speed signal, if the actual speed indicated by the actual speed signal is lower than the speed indicated by the first target speed signal, the target speed generating unit outputs the first target speed signal as the target speed signal.

4. The motor drive device according to claim 1, The target speed generating unit includes a differentiating circuit for detecting an increase or decrease in the actual speed indicated by the actual speed signal. When the target speed generating unit outputs the second target speed signal as the target speed signal, if the differentiating circuit detects an increase in the actual speed, the target speed generating unit outputs the first target speed signal as the target speed signal.

5. The motor drive device according to claim 4, When the target speed generating unit outputs the second target speed signal as the target speed signal, if the differentiating circuit detects a decrease in the actual speed, it is determined that the motor is rotating in the reverse direction.

6. The motor drive device according to claim 1, The target speed generating unit outputs the first target speed signal as the target speed signal after a predetermined period of time has elapsed since the first target speed signal rises.

7. A motor driving method, which is a motor driving method based on a motor driving device, The motor driving method include: an actual speed detection step of generating an actual speed signal representing an actual speed of the motor; a target speed generating step of generating a target speed signal indicating a target speed of the motor; as well as a driving step of driving the motor in such a way that the actual speed represented by the actual speed signal approaches the target speed represented by the target speed signal, In the target speed generating step, a first target speed signal indicating a speed based on an input instruction and a second target speed signal indicating a speed higher than the actual speed when the motor drive device is started are generated. When the actual speed indicated by the actual speed signal when the motor drive device is started is higher than the speed indicated by the first target speed signal, the second target speed signal is output as the target speed signal.

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