Motor Drive Unit

Abstract

To provide a motor driving device in which an increase of power consumption due to operation of a fan is not caused, and further, and sludge, etc. can be removed without requiring addition of a mechanism for connecting a rotor and the fan.SOLUTION: A motor driving device 100 drives a motor 30 having a fan unit. The motor driving device 100 includes a start check unit 50 that, upon detecting that power is supplied to a servo amplifier 40 for driving the motor 30, outputs a signal indicating the power supply, and a vibration command unit 60 that, upon receiving the signal indicating the power supply from the start check unit 50, transmits a command for vibrating a rotor 11 of the motor 30 to the servo amplifier 40.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a motor drive device. [Background technology]

[0002] In devices such as blowers and electric motors with cooling fans, devices that have a configuration to prevent malfunctions caused by dust, liquid mist, etc. adhering to the inside of the device are known. In this regard, Patent Document 1 describes a blower control device that automatically performs reverse rotation operation after the forward rotation of the fan ends (Abstract). Patent Document 2 describes a ventilation device that removes dust adhering to a fan by controlling the rotation speed of a drive motor so as to resonate with the natural frequency of the fan (Abstract). Patent Document 3 describes an electric motor with a cooling fan that has a connecting part that connects the rotor and the impeller of the cooling fan when the fan motor is stopped and disconnects the connection between the rotor and the impeller after the fan motor is started (Abstract). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2007-218216 A [Patent Document 2] JP 2009-216366 A [Patent Document 3] JP 2017-225292 A Summary of the Invention [Problem to be solved by the invention]

[0004] In motors with cooling fans, sludge that adheres to the fan may solidify, causing problems with the rotation of the fan motor or causing the fan motor to stop rotating. Configurations that require the operation of a fan to remove dust and other particles, as in Patent Documents 1 and 2, increase power consumption and require circuits to control the forward and reverse rotation of the fan motor and control the rotation speed. The motor in Patent Document 3 requires a mechanism to connect the rotor and the fan, which requires space to be secured, and also increases costs. [Means for solving the problem]

[0005] One aspect of the present disclosure is a motor drive device that drives a motor having a fan unit, the motor drive device including: a start confirmation unit that, in response to detecting that a power supply has been applied to a servo amplifier for driving the motor, outputs a signal indicating that the power supply has been applied; and a start confirmation unit that, in response to receiving a signal indicating that the power supply has been applied from the start confirmation unit, On the other hand, the rotor of the motor is rotated alternately in the forward and reverse directions by a predetermined angle less than 90 degrees for a predetermined period of time, so that the rotor is oscillated at the predetermined angle for the predetermined period of time. and a vibration command unit that outputs a command. Effect of the Invention

[0006] With the above configuration, it is possible to accurately remove dust, sludge, etc. that has adhered or stuck to the motor when the motor is started, without inviting a situation in which power consumption increases due to the operation of the fan motor, and without requiring an additional mechanism to connect the rotor and the fan.

[0007] These and other objects, features and advantages of the present invention will become more apparent from the detailed description of exemplary embodiments of the invention that are illustrated in the accompanying drawings. [Brief description of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating an overall configuration of a motor drive device according to an embodiment. [Diagram 2] FIG. 2 is a functional block diagram of a servo amplifier. [Diagram 3]FIG. 4 is a functional block diagram of a start confirmation unit. [Figure 4] FIG. 2 is a diagram for explaining a state in which the motor is operating in response to a command to rotate the motor forward or backward. [Figure 5A] 5B is a flowchart showing a series of processes from confirmation of power-on by a start confirmation unit and a vibration command unit to an operation of vibrating a motor. [Figure 5B] 5B is a flowchart showing a series of processes from confirmation of power-on by a start confirmation unit and a vibration command unit to an operation of vibrating a motor, together with FIG. 5A. [Figure 6A] 1 is a diagram showing a state in which an electromagnetic force in the forward direction is generated in a rotor by a rotating magnetic field. [Figure 6B] 13 is a diagram showing a state in which the rotor has rotated a specified angle in the forward direction. FIG. [Figure 6C] 1 is a diagram showing a state in which an electromagnetic force in a reverse direction is generated in a rotor by a rotating magnetic field. [Figure 6D] 13 is a diagram showing a state in which the rotor has rotated in the reverse direction by a specified angle. FIG. [Figure 7A] FIG. 13 is a diagram showing a state in which a rotating magnetic field in the forward direction is generated. [Figure 7B] 1 is a diagram showing a state in which eddy currents are generated in a rotor by a rotating magnetic field in the forward direction. [Figure 7C] 11 is a diagram showing a state in which an electromagnetic force in the forward rotation direction is generated in a rotor. FIG. [Figure 8A] FIG. 13 is a diagram showing a state in which a rotating magnetic field in a reverse direction is generated. [Figure 8B] 1 is a diagram showing a state in which eddy currents are generated in a rotor due to a rotating magnetic field in a reverse direction. [Figure 8C] 11 is a diagram showing a state in which an electromagnetic force in a reverse direction is generated in a rotor. FIG. [Figure 9] FIG. 13 is an image diagram showing a state in which sludge is removed by vibrating a rotor. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Next, an embodiment of the present disclosure will be described with reference to the drawings. In the drawings, similar components or functional parts are given similar reference symbols. To facilitate understanding, the scale of these drawings is appropriately changed. In addition, the form shown in the drawings is one example for implementing the present invention, and the present invention is not limited to the illustrated form.

[0010] Fig. 1 is a diagram showing the overall configuration of a motor drive device 100 according to an embodiment. As shown in Fig. 1, the motor drive device 100 includes a motor 30 and a motor control unit 70 that controls the motor 30. The motor drive device 100 can be used in various machines, such as machine tools, robots, forging machines, injection molding machines, various electrical appliances, trains, and automobiles.

[0011] The motor 30 has a motor body 10 and a fan unit 20 attached to the rear of the motor body 10. The motor body 10 has, as main components, a rotor 11, a stator 12, a drive shaft 14, and a body cover 13. The fan unit 20 has a fan motor 22, fan blades 23, and a fan cover 21. The motor 30 is an induction motor in this embodiment, but other types of motors such as a synchronous motor may also be used.

[0012] The motor control unit 70 includes a servo amplifier 40, a start confirmation unit 50, and a vibration command unit 60. The servo amplifier 40 converts the AC power supplied from the AC power supply 90 into a DC voltage that can be used internally, and generates a drive signal for driving the motor 30 in response to a command input from the outside. The start confirmation unit 50 detects that the servo amplifier 40 has been powered on, and transmits a signal indicating that the servo amplifier 40 has been powered on to the vibration command unit 60 in response to the detection of the power-on. The vibration command unit 60 transmits a command (voltage and current command) to the servo amplifier 40 to vibrate the rotor 11 of the motor 30 in response to receiving a signal indicating that the power-on has been confirmed from the start confirmation unit 50. With this configuration, the motor control unit 70 vibrates the rotor 11 of the motor 30 in response to the power-on of the servo amplifier 40, and can remove dust, sludge, and the like that has adhered or stuck to the fan blades 23 and the like.

[0013] 2 is a functional block diagram of the servo amplifier 40. The servo amplifier 40 includes a power supply unit 41 and a drive inverter 42. The AC power supply 90 is, for example, a three-phase 400V AC power supply, a three-phase 200V AC power supply, a single-phase 100V AC power supply, or the like. Note that the power supply applied to the servo amplifier 40 is not limited to these. The power supply unit 41 converts AC power into DC power and supplies it to the drive inverter 42. The power supply unit 41 can be configured with a three-phase bridge circuit or the like that converts AC power into DC power.

[0014] The drive inverter 42 converts DC power into AC power to drive the motor 30 and supplies the power to the motor 30 as drive power. For this purpose, the drive inverter 42 has, for example, an inverter. The inverter in the drive inverter 42 performs power conversion between DC power and AC power, which is the drive power of the motor 30, by controlling the on / off of each switching element based on a drive command (current / voltage command) received from the outside (vibration command unit 60, etc.). The drive inverter 42 may have a control unit (not shown) that generates a drive command signal for the inverter in response to a command (current / voltage command, etc.) received from the outside (vibration command unit 60, etc.). The inverter in the drive inverter 42 switches the internal switching elements based on the drive command signal, and converts the DC power supplied from the power supply unit 41 into AC power having a desired voltage, current, frequency, etc. for driving the motor 30 (inverse conversion operation). As a result, the motor 30 operates based on, for example, AC power with variable voltage and frequency.

[0015] FIG. 3 is a functional block diagram of the start-up confirmation unit 50. As shown in FIG. 3, the start-up confirmation unit 50 has a voltage measurement unit 51, an A / D converter 52, and a microcomputer 53. A DC voltage generated by the power supply unit 41 of the servo amplifier 40 is supplied to the voltage measurement unit 51. The voltage measurement unit 51 measures the DC voltage generated by the power supply unit 41. The voltage measurement unit 51 supplies an analog signal indicating the measured voltage to the A / D converter 52. The A / D converter 52 converts the input analog voltage value into a digital value and supplies it to a microcomputer (microcontroller) 53. The microcomputer 53 monitors the voltage value supplied from the A / D converter 52, and when the voltage value reaches a predetermined value or a predetermined voltage range, transmits a signal indicating that power-on (start-up) has been confirmed to the vibration command unit 60.

[0016] As one example, if the motor 30 is a motor for driving at 200 V, the microcomputer 53 may transmit a signal indicating that activation has been confirmed to the vibration command unit 60 when it is confirmed that the input voltage value is within the range of 200 V to 240 V. As another example, if the motor 30 is a motor for driving at 400 V, the microcomputer 53 may transmit a signal indicating that activation has been confirmed to the vibration command unit 60 when it is confirmed that the input voltage value is within the range of 400 V to 480 V.

[0017] In response to receiving a signal indicating that the start has been confirmed, the vibration command unit 60 transmits a command (voltage and current command) for vibrating the rotor 11 of the motor 30 to the driving inverter 42 of the servo amplifier 40. As an example, in this case, the vibration command unit 60 swings the rotor 11 (for example, rotates forward and backward at a small angle at high speed). FIG. 4 is a diagram for explaining a state in which the motor 30 is operating upon receiving such a command from the vibration command unit 60. Note that FIG. 4 is a cross-sectional view of a plane perpendicular to the drive shaft 14 of the motor body 10, and shows a state when viewed from the rear side (opposite the output shaft) (the same applies to FIGS. 6A to 6D, 7A to 7C, and 8A to 8C). In the illustration of FIG. 4, the clockwise direction is the forward direction, and the counterclockwise direction is the reverse direction (the same applies to FIGS. 6A to 6D, 7A to 7C, and 8A to 8C).

[0018] As an example, six windings 111 to 116 are arranged on the motor body 10. As an example, a rotating magnetic field can be generated by passing drive currents having phases different by 120° to such windings (three coils), and an electromagnetic force that rotates the rotor 11 can be generated. The vibration command unit 60 transmits commands (voltage and current commands) to the drive inverter 42 such that a first state ST1 in which a current is passed through each of the windings 111 to 116 so that an electromagnetic force F1 in a forward direction acts on the rotor 11, and a second state ST2 in which a current is passed through each of the windings 111 to 116 so that an electromagnetic force F2 in a reverse direction acts on the rotor 11 are alternately generated. The vibration command unit 60 is configured by, for example, a microcomputer (microcontroller) 61.

[0019] 5A and 5B are flow charts showing a series of processes (hereinafter, referred to as motor start-up confirmation and vibration processes) from confirmation of power-on by the start-up confirmation unit 50 and the vibration command unit 60 to the operation of vibrating the motor 30. First, when the AC power supply 90 is turned on to the servo amplifier 40 by operating the power-on switch for the servo amplifier 40 or the like (step S1), the voltage measurement unit 51 of the start-up confirmation unit 50 measures the voltage of the turned-on power supply (step S2).

[0020] The microcomputer 53 monitors the voltage value output from the A / D converter 52 and determines whether the voltage value is within a predetermined range (step S3). If the voltage value is not yet within the predetermined range, the microcomputer 53 continues to monitor the voltage (S3: NO). If the voltage value is within the predetermined range (S3: YES), the microcomputer 53 transmits a signal indicating that the start-up has been confirmed to the vibration command unit 60 (step S4).

[0021] When the signal indicating that the start has been confirmed is received, the vibration command unit 60 transmits a command (current and voltage command) to rotate the rotor 11 in the normal direction to the servo amplifier 40 (driving inverter 42) (step S5). FIG. 6A shows a state in which the motor 30 starts to be driven by a command to rotate the rotor 11 in the normal direction. As shown in FIG. 6A, a current flows through the windings 111-116 (three coils) of the stator 12 as shown in the figure, and the stator 12 generates a rotating magnetic field M1 that rotates in the upward direction of the figure and in the normal direction (clockwise in the figure) C1. The rotation of the rotating magnetic field M1 in the normal direction C1 generates an eddy current in the rotor 11, which generates an electromagnetic force F1 in the normal direction (clockwise in the figure) in the rotor 11. Therefore, the rotor 11 rotates in the same direction as the rotating magnetic field M1.

[0022] The motor 30 has a position sensor (not shown), and a detection signal of the position sensor is fed back to the servo amplifier 40. The position sensor is, for example, an optical encoder. In step S6, for example, the vibration command unit 60 acquires the output of the position sensor via the servo amplifier 40 and obtains the rotation angle of the rotor 11. As shown in FIG. 6B, when the rotor 11 rotates from the initial position P0 to a position P1 and the rotation angle of the rotor 11 in the forward direction reaches a designated angle φ (S7: YES), the vibration command unit 60 stops sending a command to rotate the rotor 11 in the forward direction (step S8). As a result, as shown in FIG. 6B, the current flowing through the windings 111-116 is stopped, and the electromagnetic force F1 also disappears. Note that the measurement of the rotation angle is continued until the rotation angle of the rotor 11 reaches the designated angle φ (S7: NO). As an example, the angle φ is less than 90°.

[0023] Next, in step S9 (FIG. 5B), the vibration command unit 60 transmits a command (current and voltage command) to the servo amplifier 40 to rotate the rotor 11 in the reverse direction. FIG. 6C shows a state in which the motor 30 starts to be driven by the command to rotate the rotor 11 in the reverse direction. As shown in FIG. 6C, a current flows through the windings 111-116 (three coils) of the stator 12 in the opposite direction to that during forward rotation (FIG. 6A), and a rotating magnetic field M2 is generated that rotates downward in the figure and in the reverse direction (counterclockwise in the figure). The rotation of the rotating magnetic field M2 in the reverse direction C2 generates an eddy current in the rotor 11, which generates an electromagnetic force F2 in the reverse direction in the rotor 11. Therefore, the rotor 11 rotates in the same direction as the rotating magnetic field M2.

[0024] In step S10, for example, the vibration command unit 60 obtains the output of the position sensor and determines the rotation angle of the rotor 11. As shown in Fig. 6D, when the rotor 11 returns from position P1 to the initial position P0 and the rotation angle of the rotor 11 in the reverse direction reaches the specified angle φ (S11: YES), the vibration command unit 60 stops sending the command to rotate the rotor 11 in the reverse direction (step S12). As a result, as shown in Fig. 6D, the current flowing through the windings 111-116 is stopped and the electromagnetic force F2 also disappears. Note that the measurement of the rotation angle continues until the rotation angle of the rotor 11 reaches the specified angle φ (S11: NO).

[0025] Next, the vibration command unit 60 judges whether the rotor 11 has rotated forward and backward for a predetermined time (step S13). If the operation of rotating the rotor 11 forward and backward has not reached the predetermined time, the process continues from step S5 (S13: NO). If the operation of rotating the rotor 11 forward and backward has reached the predetermined time (S13: YES), this process ends. Through the above process, the rotor 11 can be rotated forward and backward repeatedly for a predetermined time. By oscillating the rotor 11 in this way (in other words, by vibrating the rotor 11), the entire motor 30 can be vibrated, and dust, sludge, etc. attached or fixed to the fan blades 23, etc. in the fan unit 20 can be removed. The frequency, angle, and time for oscillating the rotor 11 can be appropriately determined. For example, the rotor 11 may be oscillated at a small angle at high speed.

[0026] Here, with reference to Figs. 7A to 7C, it will be described how an electromagnetic force F1 in the forward rotation direction is generated in the rotor 11 due to an eddy current generated by a rotating magnetic field M1 rotating in the forward rotation direction C1.

[0027] When a rotating magnetic field M1 rotating in the forward direction C1 is generated as shown in FIG. 7A, an eddy current that generates a magnetic field in a direction that prevents the magnetic field from increasing (opposite to the rotating magnetic field M1) is generated in a portion of the surface of the rotor 11 corresponding to the direction of the rotating magnetic field M1 (FIG. 7B). Reference numerals 212 and 213 indicate the direction of the current (induced current) on the side closer to the rotating magnetic field M1 (the portion where the eddy currents overlap) in such an eddy current. On the other hand, an eddy current that generates a magnetic field in a direction that compensates for the decrease in the magnetic field (the same direction as the rotating magnetic field M1) is generated on the opposite side of the direction of the rotating magnetic field M1 in the vicinity of the surface of the rotor 11 (FIG. 7B). Reference numerals 211 and 214 indicate the direction of the current (induced current) on the side closer to the rotating magnetic field M1 (the portion where the eddy currents overlap). An electromagnetic force F1 acts on the rotor 11 due to the rotating magnetic field M1 and the induced currents 211, 212, 213, and 214 (FIG. 7C).

[0028] Next, with reference to Figs. 8A to 8C, it will be described how an electromagnetic force F2 in the reverse direction is generated in the rotor 11 due to an eddy current generated by a rotating magnetic field M2 rotating in the reverse direction C2.

[0029] When a rotating magnetic field M2 rotating in the reverse direction C2 is generated as shown in FIG. 8A, an eddy current that generates a magnetic field in a direction that prevents the magnetic field from increasing (opposite to the rotating magnetic field M2) is generated in a portion of the rotor 11 near the surface of the rotor 11 that corresponds to the direction of the rotating magnetic field M2 (FIG. 8B). Reference numerals 224 and 221 indicate the direction of the current (induced current) on the side closer to the rotating magnetic field M2 (the portion where the eddy currents overlap). On the other hand, an eddy current that generates a magnetic field in a direction that compensates for the decrease in the magnetic field (the same direction as the rotating magnetic field M2) is generated on the opposite side of the direction of the rotating magnetic field M2 near the surface of the rotor 11 (FIG. 8B). Reference numerals 223 and 222 indicate the direction of the current (induced current) on the side closer to the rotating magnetic field M2 (the portion where the eddy currents overlap). An electromagnetic force F2 acts on the rotor 11 due to the rotating magnetic field M2 and the induced currents 221, 222, 223, and 224 (FIG. 8C).

[0030] As described above, according to this embodiment, it is possible to accurately remove dust, sludge, etc. that has adhered or stuck to the motor when the motor is started, without inviting a situation in which power consumption increases due to the operation of the fan motor, and without requiring an additional mechanism to connect the rotor and the fan.

[0031] 9 shows an image of a situation in which sludge 301 adhered between the fan blades 23 and the inner surface of the fan cover 21 is removed by vibrating the rotor 11 when the power is turned on. Note that FIG. 9 is a view of the inside of the fan unit 20 as seen from the rear. According to this embodiment, the magnetic flux from the stator 12 is controlled so as to vibrate the rotor 11 when the motor 30 is started. Then, the vibration of the rotor 11 is transmitted to the fan cover 21 and the fan blades 23, and the sludge between the fan blades 23 and the fan cover 21 can be peeled off and released from adhesion.

[0032] Although the present invention has been described using exemplary embodiments, those skilled in the art will understand that modifications and various other changes, omissions, and additions can be made to the above-described embodiments without departing from the scope of the present invention.

[0033] The configurations described in the above embodiments can be applied to various motors that can cause the rotor to perform a swing motion in response to a command.

[0034] 2 and 3 are merely examples, and other functional allocations are possible. For example, the function of the power supply unit 41 arranged in the servo amplifier 40 may be arranged in the start confirmation unit 50.

[0035] The microcomputer (microcontroller) used in the above-described embodiments is an integrated circuit incorporating a CPU core, memory (ROM, RAM, non-volatile memory, etc.), a timer, an input / output interface, and the like.

[0036] The program for executing all or part of the motor start confirmation and vibration processing in the above-described embodiment can be recorded on various computer-readable recording media (e.g., semiconductor memories such as ROM, EEPROM, and flash memory, magnetic recording media, and optical discs such as CD-ROM and DVD-ROM). [Explanation of symbols]

[0037] 10 Motor body 11 Rotor 12 Stator 13 Main unit cover 14 Drive shaft 20 Fan Unit 21 Fan cover 22 Fan motor 23 Fan Blades 30 Motor 40 Servo Amplifier 41 Power supply section 42 Drive inverter 50 Startup confirmation section 51 Voltage measurement section 52 A / D converter 53 Microcomputer 60 Vibration command section 61 Microcomputer 90 AC power supply 100 Motor drive device F1, F2 electromagnetic force M1, M2 rotating magnetic field 111, 112, 113, 114, 115, 116 Windings

Claims

1. A motor drive device that drives a motor having a fan unit, a start confirmation unit that outputs a signal indicating that a power supply has been turned on in response to detection that a power supply has been turned on to a servo amplifier for driving the motor; a vibration command unit that, in response to receiving a signal indicating that the power supply has been turned on from the start confirmation unit, sends a command to the servo amplifier to rotate a rotor of the motor alternately in a forward rotation direction and a reverse rotation direction by a predetermined angle less than 90 degrees for a predetermined period of time, thereby oscillating the rotor at the predetermined angle for the predetermined period of time; A motor drive device comprising:

2. A motor driving device as described in claim 1, wherein the motor is an induction motor or a synchronous motor.

3. 2. The motor drive device according to claim 1, wherein the command is a command to cause a stator of the motor to generate a rotating magnetic field that rotates alternately in the forward direction and the reverse direction by the predetermined angle, so that the rotor continues to rotate alternately in the forward direction and the reverse direction by the predetermined angle for the predetermined period of time.

4. A motor driving device as described in any one of claims 1 to 3, wherein the command is a command to oscillate the rotor at the specified angle for the specified time at a specified frequency.

Images