CN117997168A - Motor control device and motor control method - Google Patents
Motor control device and motor control method Download PDFInfo
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- CN117997168A CN117997168A CN202311424788.4A CN202311424788A CN117997168A CN 117997168 A CN117997168 A CN 117997168A CN 202311424788 A CN202311424788 A CN 202311424788A CN 117997168 A CN117997168 A CN 117997168A
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- 238000000034 method Methods 0.000 title claims description 15
- 238000001514 detection method Methods 0.000 claims abstract description 32
- 238000005070 sampling Methods 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 230000005856 abnormality Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012806 monitoring device Methods 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
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Abstract
The invention provides a motor control device for controlling a three-phase motor having a U-phase coil, a V-phase coil and a W-phase coil, which can appropriately judge the locking state of the three-phase motor. The motor control device (1) comprises: a current detection unit (7) that detects currents flowing through a U-phase coil (3U), a V-phase coil (3V), and a W-phase coil (3W) of the three-phase motor (2), respectively; a lock state detection unit (8) that detects the lock state of the three-phase motor (2) on the basis of the detection result of the current detection unit (7); and a motor control unit (5) that stops the three-phase motor (2) when the lock state detection unit (8) detects that the three-phase motor (2) is in the lock state. The lock state detection unit (8) determines that the three-phase motor (2) is in the lock state when the state in which the absolute value of the current flowing through any one of the U-phase coil (3U), the V-phase coil (3V), and the W-phase coil (3W) is equal to or greater than a predetermined reference current value continues for a predetermined reference duration.
Description
Technical Field
The present invention relates to a motor control device for controlling a three-phase motor. The invention also relates to a motor control method for controlling a three-phase motor.
Background
Conventionally, a drive monitor device for a dc motor is known (for example, refer to patent document 1). In the drive monitoring device described in patent document 1, when a current equal to or greater than a preset stop current threshold value continues to flow in the dc motor for a lock monitoring time or longer, the supply of electric power to the dc motor is stopped as a lock abnormality of the dc motor in which the output shaft of the dc motor is locked and the dc motor is stopped.
Conventionally, a motor control unit for controlling a three-phase motor having a U-phase coil, a V-phase coil, and a W-phase coil is known (for example, refer to patent document 2). The motor control unit described in patent document 2 includes: a motor control unit that controls rotation of the three-phase motor by a PWM signal; and an inverter that applies a drive voltage to the U-phase coil, the V-phase coil, and the W-phase coil based on an output signal from the motor control unit. The inverter includes a switching element for a U-phase coil, a switching element for a V-phase coil, and a switching element for a W-phase coil.
[ Prior Art literature ]
[ Patent literature ]
Patent document 1: japanese patent laid-open No. 2020-5377
Patent document 2: japanese patent application laid-open No. 2022-141993
Disclosure of Invention
Technical problem to be solved by the invention
The inventors of the present application studied that, in a three-phase motor having a U-phase coil, a V-phase coil, and a W-phase coil, when the three-phase motor is in a locked state in which an output shaft of the three-phase motor is locked, the three-phase motor is detected to be in a locked state, and supply of electric power to the U-phase coil, the V-phase coil, and the W-phase coil is stopped. In the course of the study, the inventors of the present application determined that the three-phase motor is in the locked state when the state where the total value of the current flowing through the U-phase coil, the current flowing through the V-phase coil, and the current flowing through the W-phase coil is equal to or greater than the predetermined reference current value continues for a predetermined time.
However, in this case, as a result of the study by the inventors of the present application, it was found that, even if a large current that flows when the three-phase motor is in the locked state flows through any one of the U-phase coil, the V-phase coil, and the W-phase coil, the total value of the currents flowing through the three-phase coils does not necessarily become equal to or greater than the reference current value, and the locked state of the three-phase motor may not be appropriately determined. In addition, if the locked state of the three-phase motor cannot be appropriately determined, the switching element is highly likely to be damaged by the influence of heat.
Accordingly, an object of the present invention is to provide a motor control device for controlling a three-phase motor having a U-phase coil, a V-phase coil, and a W-phase coil, which is capable of appropriately determining a locked state of the three-phase motor. Another technical problem of the present invention is to provide a motor control method for controlling a three-phase motor having a U-phase coil, a V-phase coil, and a W-phase coil, which is capable of appropriately discriminating a locked state of the three-phase motor.
Technical proposal for solving the technical problems
In order to solve the above-described problems, a motor control device according to the present invention is a motor control device for controlling a three-phase motor having a U-phase coil, a V-phase coil, and a W-phase coil, comprising: a current detection unit that detects currents flowing through the U-phase coil, the V-phase coil, and the W-phase coil, respectively; a lock state detection unit that detects a lock state of the three-phase motor based on a detection result of the current detection unit; and a motor control unit that stops the three-phase motor when the lock state detection unit detects that the three-phase motor is in the lock state, and determines that the three-phase motor is in the lock state when a state in which an absolute value of a current flowing through any one of the U-phase coil, the V-phase coil, and the W-phase coil is equal to or more than a predetermined reference current value continues for a predetermined reference duration.
In the motor control device according to the present invention, the lock state detection unit determines that the three-phase motor is in the lock state when a state in which the absolute value of the current flowing through any one of the U-phase coil, the V-phase coil, and the W-phase coil is equal to or greater than a predetermined reference current value continues for a predetermined reference duration. Therefore, in the present invention, when a large current flowing when the three-phase motor is in the locked state flows through any one of the U-phase coil, the V-phase coil, and the W-phase coil, the locked state of the three-phase motor can be appropriately determined based on the current flowing through any one of the U-phase coil, the V-phase coil, and the W-phase coil.
In the present invention, for example, the reference current value is a value equal to or less than the maximum current flowing through the U-phase coil, the V-phase coil, and the W-phase coil, and the reference duration is set to a time exceeding: when the three-phase motor is rotated at the lowest rotation speed at the time of normal use of the three-phase motor and when the maximum current flows through the U-phase coil, the V-phase coil, and the W-phase coil, the absolute value of the current flowing through the U-phase coil, the V-phase coil, and the W-phase coil becomes equal to or higher than the reference current value.
In order to solve the above-described problems, the motor control method according to the present invention is a motor control method for controlling a three-phase motor having a U-phase coil, a V-phase coil, and a W-phase coil, wherein when a state in which an absolute value of a current flowing through any one of the U-phase coil, the V-phase coil, and the W-phase coil is equal to or greater than a predetermined reference current value continues for a predetermined reference duration, it is determined that the three-phase motor is in a locked state, and the three-phase motor is stopped.
In the motor control method according to the present invention, when the state in which the absolute value of the current flowing through any one of the U-phase coil, the V-phase coil, and the W-phase coil is equal to or greater than the predetermined reference current value continues for the predetermined reference duration, it is determined that the three-phase motor is in the locked state. Therefore, if the three-phase motor is controlled by the motor control method of the present invention, when a large current flows through any one of the U-phase coil, the V-phase coil, and the W-phase coil when the three-phase motor is in the locked state, the locked state of the three-phase motor can be appropriately determined based on the current flowing through any one of the U-phase coil, the V-phase coil, and the W-phase coil.
Effects of the invention
As described above, in the motor control device according to the present invention, the locked state of the three-phase motor can be appropriately determined. In addition, if the three-phase motor is controlled by the motor control method of the present invention, the lock state of the three-phase motor can be appropriately determined.
Drawings
Fig. 1 is a block diagram for explaining the structure of a motor control device according to an embodiment of the present invention.
Fig. 2 is a diagram showing an example of current waveforms flowing through the U-phase coil, V-phase coil, and W-phase coil shown in fig. 1.
Fig. 3 is a flowchart for explaining an example of a control method of the three-phase motor when the current flowing through any one of the U-phase coil, the V-phase coil, and the W-phase coil shown in fig. 1 is equal to or higher than the reference current value.
Detailed Description
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Structure of Motor control device)
Fig. 1 is a block diagram for explaining the structure of a motor control device 1 according to an embodiment of the present invention. Fig. 2 is a diagram showing an example of current waveforms flowing through the U-phase coil 3U, V phase coil 3V and the W-phase coil 3W shown in fig. 1.
The motor control device 1 of the present embodiment is a device for controlling a three-phase motor 2 (hereinafter referred to as "motor 2"). The motor 2 is a three-phase brushless motor. The motor 2 includes a rotor and a stator. The rotor has permanent magnets. The stator includes U-phase coil 3U, V-phase coil 3V and W-phase coil 3W, and a stator core having salient poles around which U-phase coil 3U, V-phase coil 3V and W-phase coil 3W are wound, respectively.
Currents Iu, iv, iw (see fig. 2) which vary in a sinusoidal manner and are each shifted in phase by 120 ° flow through the U-phase coil 3U, V-phase coil 3V and the W-phase coil 3W. In fig. 2, waveforms of currents Iu, iv, iw flowing through the U-phase coil 3U, V and the W-phase coil 3W when the maximum value of the absolute values of the currents flowing through the U-phase coil 3U, V and the W-phase coil 3W becomes the maximum current when the motor 2 is rotated at the lowest rotation speed at the time of normal use of the motor 2 are illustrated. The maximum current is defined based on rated currents flowing through the U-phase coil 3U, V phase coil 3V and the W-phase coil 3W, for example. In the present embodiment, the maximum current is a value 3 times the rated current.
The motor control device 1 includes: a motor control unit 5 that controls rotation of the motor 2; a motor driving unit 6 for applying a driving voltage to the U-phase coil 3U, V phase coil 3V and the W-phase coil 3W in accordance with a control signal outputted from the motor control unit 5; a current detection unit 7 that detects currents flowing through the U-phase coil 3U, V-phase coil 3V and the W-phase coil 3W, respectively; and a lock state detection unit 8 that detects the lock state of the motor 2 based on the detection result of the current detection unit 7. When the motor 2 is in the locked state, the rotation of the motor 2 with respect to the control signal of the motor control unit 5 is difficult, and the rotation speed of the motor 2 becomes very low or the motor 2 is stopped.
The motor driving unit 6 is a servo amplifier or an inverter. The motor driving unit 6 has a switching element such as a MOSFET. An encoder for detecting the rotation angle and the rotation speed of the rotor of the motor 2 is electrically connected to the motor control unit 5. The motor control unit 5 outputs a control signal to the motor driving unit 6 based on a detection result of the encoder or the like, to control the rotation of the motor 2. When the locked state detection unit 8 detects that the motor 2 is in the locked state, the motor control unit 5 outputs a control signal to the motor drive unit 6 to stop the motor 2.
When the absolute value of the current flowing through any one of the U-phase coil 3U, V and the W-phase coil 3W is equal to or greater than the predetermined reference current value for a predetermined reference duration, the lock state detection unit 8 determines that the motor 2 is in the lock state. The reference current value is equal to or less than the maximum current flowing through the U-phase coil 3U, V-phase coil 3V and the W-phase coil 3W. For example, the reference current value is a current value of 70% to 85% of the maximum current flowing through the U-phase coil 3U, V-phase coil 3V and the W-phase coil 3W. The user sets a reference current value by setting a threshold value for the maximum current in the motor control device 1.
The reference duration is set to a time exceeding the following time: when the motor 2 is rotated at the lowest rotation speed at the time of normal use of the motor 2 and the maximum value of the absolute values of the currents flowing through the U-phase coil 3U, V phase coil 3V and the W-phase coil 3W becomes the maximum current (that is, when the maximum current flows through the U-phase coil 3U, V phase coil 3V and the W-phase coil 3W), the absolute values of the currents flowing through the U-phase coil 3U, V phase coil 3V and the W-phase coil 3W become the reference current value or more.
When determining the reference duration, first, when rotating the motor 2 at the lowest rotation speed at the time of normal use of the motor 2, a threshold th (see fig. 2) for setting the reference current value is set to a current waveform of the U-phase coil 3U in which the maximum value of the absolute values of the currents flowing through the U-phase coil 3U, V-phase coil 3V and the W-phase coil 3W becomes the maximum current. When the threshold value th is set, a time T (see fig. 2) from when the current value of the U-phase coil 3U is equal to or greater than the threshold value th to when the current value is equal to or less than the threshold value th is determined. In addition, a time exceeding the determined time T is taken as the reference duration. For example, when the number of poles of the motor 2 is 5, the minimum rotation speed is 4rpm, and the threshold th is 70%, the time T is about 0.76 seconds, and the reference duration is 2 seconds. The reference duration is set by the user in the motor control device 1.
(Motor control method)
Fig. 3 is a flowchart for explaining an example of a control method of the motor 2 when the current flowing through any one of the U-phase coil 3U, V and the W-phase coil 3W shown in fig. 1 is equal to or greater than a reference current value.
When the absolute value of the current flowing through any one of the U-phase coil 3U, V and the W-phase coil 3W becomes equal to or greater than the reference current value, a lock state determination control for determining whether or not the motor 2 is in the lock state is started. In the lock state determination control, first, after the lock state determination control is started with the absolute value of the current flowing through any one of the U-phase coil 3U, V and the W-phase coil 3W being equal to or greater than the reference current value (yes in step S1), the lock state detection unit 8 determines whether or not the absolute value of the current flowing through any one of the U-phase coil 3U, V and the W-phase coil 3V being equal to or greater than the reference current value is smaller than the reference current value after the sampling time has elapsed (step S2). In addition, the sampling time is a time sufficiently shorter than the reference duration.
In step S2, when the absolute value of the current flowing through any one of the U-phase coil 3U, V phase coil 3V and the W-phase coil 3W, which is equal to or greater than the reference current value, is equal to or greater than the reference current value after the sampling time elapses, the lock state detection unit 8 determines whether or not the reference duration has elapsed after the absolute value of the current flowing through any one of the U-phase coil 3U, V phase coil 3V and the W-phase coil 3W is equal to or greater than the reference current value (that is, after the lock state determination control is started) (step S3). In step S3, when the reference duration has elapsed, the lock state detection unit 8 determines that the motor 2 is in the lock state (step S4), and transmits a lock state detection signal to the motor control unit 5.
The motor control unit 5, which has received the lock state detection signal, outputs a control signal to the motor drive unit 6 to stop the motor 2 (step S5). When the motor 2 is stopped, the lock state determination control ends. On the other hand, in step S3, if the reference duration has not elapsed, the timer for measuring the sampling time is reset (step S6), and the routine returns to step S1. In step S2, when the absolute value of the current flowing through any one of the U-phase coil 3U, V and the W-phase coil 3W, which is equal to or greater than the reference current value, is smaller than the reference current value after the sampling time has elapsed, the lock state determination control ends.
(Main effects of the present embodiment)
As described above, in the present embodiment, when the state in which the absolute value of the current flowing through any one of the U-phase coil 3U, V phase coil 3V and the W-phase coil 3W is equal to or greater than the reference current value continues for the reference duration, the lock state detection unit 8 determines that the motor 2 is in the lock state. Therefore, in the present embodiment, when a large current flows through any one of the U-phase coil 3U, V and the W-phase coil 3W when the motor 2 is in the locked state, the locked state of the motor 2 can be appropriately determined based on the current flowing through any one of the U-phase coil 3U, V and the W-phase coil 3W.
(Other embodiments)
The above-described embodiments are examples of preferred embodiments of the present invention, but the present invention is not limited thereto, and various modifications and changes can be made without changing the gist of the present invention.
Description of the reference numerals
1 Motor control device
2 Motor (three-phase motor)
3U U phase coil
3V V phase coil
3W W phase coil
5. Motor control unit
7. Current detecting unit
8. A lock state detection unit.
Claims (3)
1. A control device for an electric motor is provided,
The motor control device for controlling a three-phase motor having a U-phase coil, a V-phase coil, and a W-phase coil is characterized by comprising:
A current detection unit that detects currents flowing through the U-phase coil, the V-phase coil, and the W-phase coil, respectively;
A lock state detection unit that detects a lock state of the three-phase motor based on a detection result of the current detection unit; and
A motor control unit that stops the three-phase motor when the lock state detection unit detects that the three-phase motor is in the lock state,
The lock state detection unit determines that the three-phase motor is in the lock state when a state in which an absolute value of a current flowing through any one of the U-phase coil, the V-phase coil, and the W-phase coil is equal to or greater than a predetermined reference current value continues for a predetermined reference duration.
2. The motor control device according to claim 1, wherein,
The reference current value is a value equal to or less than a maximum current flowing through the U-phase coil, the V-phase coil, and the W-phase coil,
The reference duration is set to a time exceeding the time of: when the three-phase motor is rotated at the lowest rotational speed at the time of normal use of the three-phase motor and when the maximum current flows through the U-phase coil, the V-phase coil, and the W-phase coil, the absolute value of the current flowing through the U-phase coil, the V-phase coil, and the W-phase coil becomes equal to or higher than the reference current value.
3. A method of controlling an electric motor, the method comprising,
Is a motor control method for controlling a three-phase motor having a U-phase coil, a V-phase coil, and a W-phase coil, characterized in that,
When the state in which the absolute value of the current flowing through any one of the U-phase coil, the V-phase coil, and the W-phase coil is equal to or greater than a predetermined reference current value continues for a predetermined reference duration, it is determined that the three-phase motor is in a locked state, and the three-phase motor is stopped.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2022-176030 | 2022-11-02 | ||
| JP2022176030A JP2024066585A (en) | 2022-11-02 | 2022-11-02 | MOTOR CONTROL DEVICE AND MOTOR CONTROL METHOD |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117997168A true CN117997168A (en) | 2024-05-07 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311424788.4A Pending CN117997168A (en) | 2022-11-02 | 2023-10-30 | Motor control device and motor control method |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JP2024066585A (en) |
| CN (1) | CN117997168A (en) |
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2022
- 2022-11-02 JP JP2022176030A patent/JP2024066585A/en active Pending
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2023
- 2023-10-30 CN CN202311424788.4A patent/CN117997168A/en active Pending
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| JP2024066585A (en) | 2024-05-16 |
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