JP3277521B2 - Induction motor control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable speed control device for an induction motor and a method for operating the same, and more particularly to a case where one or more induction motors are operated by one or more inverter devices and a plurality of inverters are operated. The present invention relates to a variable speed control device in a case where various types of control methods are mixed and an operation method thereof.

[0002]

2. Description of the Related Art The operation of a conventional inverter device by so-called V / F control (hereinafter referred to as V / F control) in which the ratio of the output voltage V to the output frequency F is set to a predetermined value and the induction motor is controlled at a variable speed is 1 When one or a plurality of induction motors are selectively operated by one inverter device, the V / F characteristics are set by selecting only one of the V / F characteristics prepared in the inverter devices and stopping. Was fixed. That is, the setting of the V / F characteristic in this case is performed by selecting and setting only one V / F characteristic according to each induction motor from the V / F characteristics prepared for the inverter device while the inverter device is stopped. The electric motor has been alternately operated by switching ON and OFF the contacts such as contactors between the inverter device and the induction motor based on the operation command.

Further, in a system using a conventional vector control (hereinafter referred to as FB control) inverter device in which an induction motor is controlled at a variable speed by vector control with speed feedback, only one induction motor is operated by one inverter device. It is possible, and only one type of internal setting such as the induction motor constant of the inverter device is fixedly set. Therefore, when a plurality of induction motors are used, the same number of inverter devices are required. In addition, since switching motors is not considered, when using a plurality of motors having different circuit constants, there is a lack of flexibility, such as requiring a plurality of inverters, and there is a problem economically. Was.

As described above, conventionally, when a plurality of induction motors having different characteristics are driven by different control methods, a control method and control constant corresponding to 1: 1 for each induction motor are used.
The number of inverter devices was set.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a sensorless vector control for controlling the induction motor at a variable speed by the V / F control, the FB control, or the vector control without speed feedback (for example, Japanese Patent Laid-Open No. 32788/1990).
reference. Hereinafter, this control scheme to be selected in accordance with a plurality of control method) such as SLV control to driving conditions and driving pattern such as the inverter device and any motor control
The purpose of the present invention is to realize an economical system that can be shared and used in a control system .

[0006]

In order to solve this problem, the ratio between the output voltage V and the output frequency F of the inverter device is determined.
V / F control operation that operates as a predetermined value, inverter
FB control operation for operating the unit by speed feedback control
Invert the inverter device without speed feedback signal.
Of the multiple control methods for SLV control operation that control
At least two types of control methods are switched and one
Speed control of two or more induction motors with a motor device
In the drive device of the induction motor, the plurality of control methods
A set of a plurality of corresponding predetermined control constants is stored in the inverter device.
Storage means for storing in the device; and
Speed feedback during operation with FB control operation control method
If a signal abnormality is detected, the inverter
Equations and control constants for the control method of the SLV control operation and this
Means for switching to a control constant corresponding thereto, and
Based on the switched control method and control constants,
Speed control of the induction motor connected to the inverter device.
Control means .

[0007]

[Function] The inverter device operates by the control method of the FB control operation.
When an abnormality of the speed feedback signal is detected during running
Sets the inverter system control method and control constants to SLV control.
Switching to the control method of the operation and the corresponding control constant
Based on the switched control method and control constants.
The induction motor connected to the inverter device
Is speed controlled.

[0008]

FIG. 1 shows an example of a circuit configuration of an inverter according to the present invention. The power supplied from the power supply 1 is the inverter 2
Is rectified by the rectifier circuit 3 in the inside, passes through the inrush prevention circuit 4, and is stored in the smoothing circuit 5. Thereafter, the motor 8 is converted into an arbitrary voltage and an arbitrary frequency by the inverse conversion circuit 6 and drives the motor 8. The transmitter 9 detects the number of rotations of the motor 8 and performs inversion.
Feedback to the customer. Signals of the current detection circuit 7 and other detection circuits 11 are transmitted to an inverter control circuit 17. This inverter 2 is supplied with V /
The F control circuit 12, the FB control circuit 14, and the SLV control circuit 13 can be switched, and there are a case where the signal from the other detection circuit 11 is switched by the control circuit 17 and a case where the signal is switched from the control circuit 19 of the system. is there. The control constants required for each are the operator 18
A constant stored in the storage circuit 16 is selected, or is directly input from the system control circuit 19. The one controlled as described above drives the inverse conversion circuit 6 through the waveform synthesis circuit 10. Fig. 2 shows the control prepared inside the inverter.
Shows a table of constants . For each induction motor (A, B, C, etc. in the example of FIG. 2), FB control, SLV control and V /
Control constants when controlling in each of the F controls (for example,
FB signal, induction motor constant, V / F characteristics, protection level,
The operating conditions, other constants for control, etc.) are stored in the storage circuit 16 or the system control circuit 19 of the inverter device in association with the mode number. The inverter operates according to the selected control method and constant.

FIG. 3 shows a specific embodiment of an automatic warehouse control system including the inverter device of the present invention. Power supply 21
The power is supplied to the inverter device 22 from the electromagnetic contactor 2.
The elevator induction motor 26 is driven through 3, and the rotation speed of the induction motor 26 is fed back from the transmitter 27 to the inverter device 22. The inverter device 37 drives the fork induction motor 33 through the electromagnetic contactor 36 or the traveling induction motor 34 through the electromagnetic contactor 35. 38
Is a system control circuit using a sequence controller or the like. The electromagnetic contactors 24 and 25 are connected to the inverter device 22 when the inverter device 37 fails.
And fork induction motor 33 and traveling induction motor 34
This is an emergency circuit for driving the. The movable part of this system is a traveling body 2 driven by a traveling induction motor 34.
9 and an elevating body 30 driven by an elevating induction motor 26
And fork 3 driven by fork induction motor 33
It consists of two. The luggage 31 is placed on a fork 32, moved by the traveling body 29 and the elevating body 30 to a designated address of the storage shelf 28, and stored or carried out by the fork 32.

In the prior art, three inverters were separately required for lifting, traveling, and fork. In this embodiment, however, the inverter 37 controls the traveling induction motor 34 by SLV control, and the V / F In order to control the fork induction motor 33 by switching it, two inverter devices are used in total together with the inverter device 22 that controls the induction motor 26 by FB. In order to minimize the transfer time as a system, the traveling induction motor 34 and the lifting / lowering induction motor 26 may be started at the same time, and these may be provided with separate inverter devices. Of course, in a system in which the transport time does not matter so much, the system may be sequentially started and one inverter device may be used as a whole.

FIG. 4 shows an operation flowchart of the traveling and fork inverter device 37. The traveling control or the fork driving is determined by the system control circuit 38 (step 40). For traveling operation, set the electromagnetic contactor 36 to O
The FF is performed and the electromagnetic contactor 35 is turned on to connect the inverter device 37 and the induction motor 34 (step 41).
In this case, in the present embodiment, a mode selection signal for selecting a control constant of mode 8 which is the SLV control of the induction motor 34 is sent to the inverter device 37, and the control constant stored in the inverter device is selectively set or controlled. Circuit 38
Goes to write the control constants directly into the inverter device 37 (step 42). After that, a traveling operation is performed (Step 4).
3). In the case of a fork operation, the inverter device 37 and the induction motor 33 are connected by turning off the electromagnetic contactor 35 and turning on the electromagnetic contactor 36 (step 44). In this case, a signal for selecting the control constant of the mode 6 which is the V / F control of the induction motor 33 is sent to the inverter device 37 to select and set the control constant stored in the inverter device. circuit 38 is directly system to the inverter 37
Go to write the constant (step 45). Thereafter, a fork operation is performed (step 46).

FIG. 5 shows a flowchart in the case where the FB signal of the inverter device 22 becomes abnormal. When the abnormality of the FB signal is detected (step 50), the inverter device control circuit 22 notifies the system control circuit 38 of the abnormality of the FB signal (step 51). At this time, the feed itself inverter device 22, or a mode <br/> over de switching signals the system control circuit 38 switches the control constants of the inverter device from the mode 1 to the mode 2 to the inverter device 22 inverter -
Switch from FB control to SLV control (step 5
2). Thereafter, SLV control is performed (step 53). If the inverter device 37 fails, the electromagnetic contactor 2
By changing the mode of the inverter device in accordance with the switching of the electromagnetic contactor 4 or the electromagnetic contactor 25, the operation efficiency is deteriorated, but the system can be operated so as to avoid a complete stop of the system.

As described above, one inverter can select V / F control, FB control or SLV control based on a signal inside the inverter or a signal from an external control circuit. At this time, the necessary constants are stored in the inverter device for the necessary modes so that the constants can be selected by an internal signal or an external signal. Also, the necessary constants can be set directly in the inverter device by an external control circuit. The constants inside the inverter device can be easily set and changed by an operator.

[0014]

The method of controlling the FB control operation using the inverter device
An error in the speed feedback signal was detected during operation using the formula
When the control method and control constant of the inverter device are SL
Switch to the control method of V control operation and the corresponding control constant.
By switching, the invitation connected to the inverter
The conductive motive can be operated and the system can be strengthened.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of an inverter according to an embodiment of the present invention.

FIG. 2 shows storage contents of an inverter device according to an embodiment of the present invention.

FIG. 3 is a configuration diagram of a transport device according to an embodiment of the present invention.

FIG. 4 shows an example of a flowchart in a normal state provided for an embodiment of the present invention.

FIG. 5 shows an example of a flowchart at the time of abnormality provided in an embodiment of the present invention.

[Description of abbreviations]

DESCRIPTION OF SYMBOLS 1 ... Power supply 2 ... Inverter apparatus 3 ... Rectifier circuit 4 ... Inrush prevention circuit 5 ... Smoothing circuit 6 ... Inverting circuit 7 ... Current detection circuit 8 ... Motor 9 ... Transmitter 10 ... Waveform synthesis circuit, 11 detection circuit, 12 V / F control circuit, 13 ...
SLV control circuit, 14 FB control circuit, 15 control switching circuit, 16 storage circuit, 17 inverter control circuit, 18 operator, 19 system control circuit, 21
... Power supply, 22 ... Inverter device for elevating, 23 ... Electromagnetic contactor for elevating, 24 ... Electromagnetic contactor for fork when abnormal, 25 ...
Electromagnetic contactor for traveling at abnormal time, 26 ... Induction motor for lifting and lowering, 2
7 ... transmitter, 28 ... storage shelf, 29 ... traveling body, 30 ... elevating body, 31 ... luggage, 32 ... fork, 33 ... fork induction motor, 34 ... traveling induction motor, 35 ... traveling electromagnetic contactor 36: electromagnetic contactor for fork, 37: inverter device for traveling and fork, 38: system control circuit

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-131396 (JP, A) JP-A-2-142393 (JP, A) JP-A-4-33583 (JP, A) JP-A-2- 280688 (JP, A) JP-A-61-196788 (JP, A) Patent 3128833 (JP, B2) Patent 2685631 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02P 5 / 50 H02P 5/41 302

Claims (1)

(57) [Claims] 1. A V / F control operation in which the ratio between the output voltage V and the output frequency F of the inverter device is set to a predetermined value, and a F / F operation in which the inverter device is operated by speed feedback control.
B control operation, at least two types of control methods are switched among a plurality of control methods of SLV control operation in which the inverter device is vector-controlled without a speed feedback signal, and two or more induction motors are operated by one inverter device. A drive unit for an induction motor that controls the speed of the motor, a storage unit that stores a set of a plurality of predetermined control constants corresponding to the plurality of control systems in the inverter device, and a control method of controlling the FB control operation by the inverter device. in SL before the control system and the control constants of the inverter device when detecting an abnormality in the speed feedback signal during operation SLV
Means for switching set in the control system and the control constant corresponding to the control operation, the control means for the speed control the connected the induction motor to the inverter device based on the control method and the control constant is changed the cut A control device for an induction motor, comprising: