JPH0880092A - Drive controller of motor - Google Patents

Abstract

PURPOSE: To protect each motor from overload, making use of an electron thermal installed in an inverter, by controlling a plurality of motors not driven at the same time with one inverter. CONSTITUTION: A motor 9 for traveling is connected to the output terminals U, V, and W of an inverter 16 through the normal by open contact MC1a of an electromagnetic contactor MC1, and a motor 11 for drive of a lifter is connected to it through the normal open contact pAC2a an electromagnetic contactor MC2. A truck controller 15 is provided with an exciting and demagnetizing circuit 23 for both electromagnetic contactor MC1 and MC2. CPU 24 installed in the inverter 16 operates the load condition of a motor in ON condition, based on the output signal of a current detection circuit 26, and stops the drive of the motor when it reaches the criteria of overload interruption. CPU 24 judges the ON condition of both motors 9 and 11 from the open and close conditions of the normal open contact MC1a connected between the terminal TH and the terminal S, and outputs a stop command, based on the criteria of overload interruption of the motor in ON condition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor drive control device, and more particularly to a motor drive control device for a gear shift control device for a plurality of motors that are not driven simultaneously by a single inverter. .

[0002]

2. Description of the Related Art A device that uses a motor (for example, a squirrel cage induction motor) whose variable speed is controlled by an inverter as a drive source is widely used in various fields. In the case of gear shift control of a motor, a thermal type thermal relay is usually used to prevent the motor from burning, but it is not possible to detect a temperature rise due to a decrease in motor cooling during low speed operation. Therefore, the inverter is equipped with a so-called electronic thermal that protects the motor from overheating by calculating the motor temperature characteristic from the operating current value and the frequency with the built-in microcomputer.

On the other hand, an overhead traveling type transfer device for moving a load from a station in a factory or a warehouse to a station by moving along a rail erected on the ceiling is provided with an elevating device for raising and lowering the load. (For example, Japanese Patent Laid-Open No. 6-80389). In this transport device, a motor different from the traveling motor and the driving motor of the lifting device is used. For safety reasons, the elevating device is not operated during traveling, and the elevating device is activated only when traveling of the transport device is stopped.

In this type of transfer device, variable speed motors are used for both motors in order to perform work efficiently.
Moreover, since both motors are not driven at the same time, both motors are controlled at a variable speed by one inverter. As described above, the inverter is equipped with an electronic thermal in order to prevent the motor from being burned. However, the electronic thermal is intended for driving one motor. In the case of controlling with an inverter, it was necessary to provide a thermal relay on one motor and perform overload protection for the motor based on the signal from the thermal relay.

[0005]

In the conventional apparatus, although two motors controlled by the inverter are not driven simultaneously, a thermal relay must be provided for overload protection of one motor. , But the cost has increased.

The present invention has been made in view of the above problems, and an object thereof is to equip an inverter in a device in which a plurality of motors that are not driven at the same time are gearshift-controlled by one inverter. Another object of the present invention is to provide a motor drive control device capable of performing overload protection on all motors by utilizing electronic thermal.

[0007]

In order to achieve the above object, according to the invention of claim 1, in a device for controlling a shift of a plurality of motors which are not simultaneously driven by one inverter, each motor is Detecting means for detecting whether or not it is in an on state, storage means for storing an overload cutoff reference value for each motor, and a motor in an on state from a plurality of overload cutoff reference values stored in the storage means Selection means for selecting the overload cutoff reference value corresponding to the above, calculation means for calculating the load state of the motor in the on-state based on the output signal of the current detection means equipped in the inverter, and the calculation result of the calculation means. Control means for outputting a command signal for reducing the load on the motor when the overload cutoff reference value of the motor in the ON state is reached.

According to a second aspect of the present invention, the detection means is a contact of a relay for driving each motor. Also, claim 3
In the invention described in claim 1, in the invention described in claim 1 or 2, the command signal is a stop command signal for the motor.

According to the invention described in claim 4, claim 1
In the invention according to any one of claims 3 to 3, the device is an overhead traveling type conveyance device equipped with a traveling motor and a lifting device driving motor.

[0010]

According to the invention described in claim 1, the plurality of motors is one.
Shift control is performed by the inverter of the stand. The motors are never driven at the same time. The storage means stores an overload cutoff reference value for each motor. The detection means detects whether or not each motor is in the ON state. The selection means selects the overload cutoff reference value corresponding to the motor in the ON state from the plurality of overload cutoff reference values stored in the storage means. The calculation means calculates the load state of the motor in the on-state based on the output signal of the current detection means provided in the inverter. The control means outputs a command signal for reducing the load of the motor when the value indicating the load state calculated by the calculation means reaches the overload cutoff reference value of the motor in the ON state.

According to the second aspect of the invention, whether or not each motor is in the driving state is detected from the state of the contact of the relay for driving each motor. The other actions are similar to those of the first aspect of the invention.

According to the third aspect of the present invention, when the overload cutoff reference value of the motor in the ON state is reached, a motor stop command is output as a command signal for reducing the load of the motor. Other functions are similar to those of the above invention.

According to the invention described in claim 4, the traveling motor and the lifting device driving motor of the overhead traveling conveyance device are gear-shift controlled by one inverter. Other functions are similar to those of the above invention.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is embodied in an overhead traveling type carrier will be described below with reference to the drawings.

As shown in FIG. 2, an overhead traveling type transfer device 1 is provided.
Is provided with a carrier vehicle 3 that is self-propelled along a rail 2 that is installed near the ceiling, and an elevating table 5 that is suspended from the carrier vehicle 3 via a belt 4. The transport vehicle 3 includes a drive wheel 6 and a driven wheel 7 that roll on the rail 2, and a guide wheel 8 that holds a side surface of the rail 2, and the drive wheel 6 is a traveling motor 9 with a reduction gear.
Driven by

As shown in FIG. 3, an elevating device 10 for elevating the elevating table 5 includes a pair of drive pulleys 12 driven by a drive motor 11 of the elevating device and two pairs of guide pulleys 1.
4 of which the first end is fixed to the lift 5 has the second end fixed to the drive pulley 12.
Each belt 4 is wound up via the guide pulley 13 when the drive motor 11 is driven in the forward direction, and is unwound when driven in the reverse direction. And
By driving the drive motor 11 in the forward and reverse directions, the lifting platform 5 moves horizontally between a reference position near the bottom of the transport vehicle 3 and a lowered position where the load is transferred. In addition,
A power supply trolley wire (not shown) is arranged along the rail 2, and both motors 9 and 11 receive power from the power supply trolley wire via a current collector (not shown).

Next, the traveling motor 9 and the driving motor 11
An electrical configuration for controlling the above will be described with reference to FIG.
The control device 14 that controls the overhead traveling transfer device 1 includes a carriage controller 15 and an inverter 16. The trolley controller 15 controls both motors 9 and 11 via the inverter 16 based on a command from a machine operation management computer (not shown).

The inverter 16 includes a main circuit 17 and a control circuit 1.
8 and. The main circuit 17 is composed of a converter unit 20 connected to a commercial power supply 19, a smoothing circuit unit 21, and an inverter unit 22 for converting DC power into AC power. A traveling motor 9 is connected to the output terminals U, V, W of the inverter 16 via a normally open contact MC1a of an electromagnetic contactor MC1 as a motor driving relay.
Further, the drive motor 11 is connected to the output terminals U, V, W of the normally open contact MC of the electromagnetic contactor MC2 as a relay for driving the motor.
It is connected in parallel with the traveling motor 9 via 2a.

The trolley controller 15 has a 24V power supply terminal P24 and open collector output terminals OP1 and OP.
2 are provided. The terminals OP1 and OP2 can be energized from the output terminal P24 when they become L (low) level in response to a command from a CPU (not shown) built in the carriage controller 15. The terminal RUN becomes L level during the operation of the inverter 16 so that power can be supplied from the power supply terminal P24, and becomes H (high) level when the inverter 16 is stopped, so that power supply from the power supply terminal P24 is disabled.

Then, both electromagnetic contactors MC1, MC1 are provided between the terminals.
The excitation / demagnetization circuit 23 of MC2 is connected. Power terminal P
Relay CR1 for emergency stop between 24 and terminal RUN
Is connected. Between the power supply terminal P24 and the relay CR1 and the terminal OP1, a normally open contact CR of the relay CR1 is provided.
1a, a normally closed contact MC2b of the electromagnetic contactor MC2, and the electromagnetic contactor MC1 are connected in series. The normally closed contact MC1b and the electromagnetic contactor MC2 of the electromagnetic contactor MC1 are connected in series between the normally open contact CR1a and the normally closed contact MC2b and the terminal OP2.

The control circuit 18 is a central processing unit (hereinafter referred to as a CPU) 2 as a selection means, a calculation means and a control means.
It is equipped with 4. The CPU 24 is a storage device (R
It operates based on the program stored in OM). C
The PU 24 is a voltage detection circuit 2 that detects the voltage of the main circuit 17.
5 and a current detection circuit 26 as current detection means for detecting the current of the main circuit 17. The CPU 24 is connected to a storage device 27 as storage means. The storage device 27 is composed of a readable and rewritable memory (RAM) having a backup power source, and the overload cutoff reference value A of the traveling motor 9 and the overload cutoff reference value B of the drive motor 11 are stored in the storage device 27. Remembered CPU2
4 calculates the load state of the motor in the ON state based on the output signal from the current detection circuit 26, that is, from the operating current value and the frequency. Then, when the load state of the motor in the ON state reaches the overload cutoff reference value of the motor, the driving of the motor is stopped. CPU
24 and the current detection circuit 26 have the same structure as a general electronic thermal.

The CPU 24 and the carriage controller 15 are connected via a terminal FLT provided on the inverter 16 and an input terminal IP provided on the carriage controller 15. When the load state of the motor in the ON state reaches the overload cutoff reference value of the motor and the CPU 24 controls the stop of the motor, the CPU 24 outputs a failure signal to the truck controller 15 via the terminal FLT. . When the truck controller 15 receives this signal at the input terminal IP, it demagnetizes the electromagnetic contactors MC1 and MC2.

The CPU 24 is a PWM (Pulse Width Modula).
tion) circuit 28, the PWM circuit 28 is connected to the CPU 2
A control command signal is output to the inverter unit 22 in accordance with the command signal from the inverter 4. The CPU 24 compares the command signal from the carriage controller 15 and the current / voltage signals from both detection circuits 25 and 26 to determine the output voltage / frequency of the inverter 16.

An electromagnetic contactor MC1 is provided between the contact input common terminal SD and the input terminal TH provided on the inverter 16.
The normally open contact MC1a of is connected. The normally open contact MC1a constitutes a detecting means for detecting whether the traveling motor 9 and the driving motor 11 are in the ON state. When the normally open contact MC1a is closed, an L level signal is input to the CPU 24, and the CPU 24 determines that the traveling motor 9 is in the on state. CP when the normally open contact MC1a opens
The L level signal is not input to U24. When the L level signal is not input during the operation of the inverter 16, the CPU 24 determines that the traveling motor 9 is off, that is, the driving motor 11 is on. CPU
Reference numeral 24 denotes an overload cutoff reference value A of the drive motor 9 as the overload cutoff reference value when the drive motor 9 is in the ON state, and an overload cutoff reference value of the drive motor 11 when the drive motor 11 is in the ON state. Select the value B. Then, the CPU 24 outputs a stop command to the PWM circuit 28 when the value indicating the load state of the motor reaches the overload cutoff reference value.

Next, the operation of the apparatus configured as described above will be described. The traveling motor 9 is drive-controlled by the control device 14 that operates based on a command from the machine operation management computer, and the overhead traveling transfer device 1 moves between the stations along the rail 2. Then, the drive motor 11 is drive-controlled by the control device 14 in a state of being stopped at the station, and the lift 5 is moved up and down.

During operation of the overhead traveling type transport device 1, the terminal RUN is held at the L level in response to a command from the carriage controller 15, the relay CR1 is excited, and its normally-open contact CR.
1a is closed. When the transport vehicle 3 is running, the terminal O
The electromagnetic contactor MC1 is excited by keeping P1 at the L level, the normally open contact MC1a is closed, and the normally closed contact MC1b is opened. In this state, output terminals U, V, W
The normally open contact MC1a connected between the driving motor 9 and the traveling motor 9 is maintained in the closed state, and the traveling motor 9 is connected to the inverter unit 22.
Is driven at a speed corresponding to the output of. The CPU 24 determines an output voltage and a frequency for driving the traveling motor 9 according to the command based on a command from the carriage controller 15 and outputs a command signal to the PWM circuit 28. And
The inverter unit 22 is driven at a speed corresponding to the command signal of the PWM circuit 28.

While the CPU 24 is outputting a signal for driving the motor to the PWM circuit 28, the CPU 24 calculates the load state of the motor from the output signal and frequency of the current detection circuit 26, and calculates the value and the overload cutoff reference value. Compare. When the value indicating the load state reaches the overload cutoff reference value, the PWM circuit 28
The stop command is output to. When the traveling motor 9 is in the on state, the normally open contact MC1a connected to the input terminal TH of the inverter 16 is held in the closed state, and the CPU 24 receives a signal indicating that the traveling motor 9 is in the on state. Is entered. When the CPU 24 receives this signal,
The overload cutoff reference value A of the traveling motor 9 is selected as the overload cutoff reference value, and that value is compared with a value indicating the load state of the motor. Then, when the traveling motor 9 is overloaded, the CPU 24 outputs a stop command to the PWM circuit 28 to stop the traveling motor 9, and burnout due to the continuation of the overloaded state is prevented. The CPU 24 also outputs a failure signal to the carriage controller 15 via the terminal FLT. When the carriage controller 15 receives this signal, the carriage controller 15 demagnetizes the electromagnetic contactor MC1. As a result, the normally open contact MC1a, which has been held in the closed state until then, is opened, and the power supply to the traveling motor 9 is completely cut off.

With the transport vehicle 3 stopped at a predetermined position,
When operating the elevating device 10, after the output of the terminal OP1 is held in the OFF state and the electromagnetic contactor MC1 is demagnetized,
The terminal OP2 is held at the L level. Then, the electromagnetic contactor MC2 is excited to close its normally open contact MC2a and open its normally closed contact MC2b. In this state, the normally open contact MC2a connected between the output terminals U, V, W and the drive motor 11 is held in the closed state, and the drive motor 1
1 is driven at a speed corresponding to the output of the inverter unit 22.

At this time, the input terminal TH of the inverter 16
The normally open contact MC1a connected to is held open. The CPU 24 selects the overload cutoff reference value B of the drive motor 11 as the overload cutoff reference value when the signal indicating that the normally open contact MC1a is in the closed state is not input. Therefore, when the drive motor 11 is overloaded,
A stop command is output from the CPU 24 to drive the motor 11
Is stopped, and burnout due to continued overload is prevented. The CPU 24 also outputs a failure signal to the carriage controller 15 via the terminal FLT. When the carriage controller 15 receives this signal, it demagnetizes the electromagnetic contactor MC2. As a result, the normally open contact MC2a, which has been held in the closed state until then, is opened, and the power supply to the drive motor 11 is completely cut off. Since the overload cutoff reference value A and the overload cutoff reference value B can be set to desired values, they can be appropriately changed according to the usage conditions of the motor.

Even if the drive signal of the lifting device 10 is erroneously output during driving of the traveling motor 9 and the terminal OP2 goes to L level, the normally closed contact MC1b is held in the open state, so that the electromagnetic contactor MC2 is not excited and is kept in a demagnetized state. Therefore, the lifting table 5 is not moved up and down by mistake while the transport vehicle 3 is traveling. Further, even if a traveling command is erroneously output during driving of the drive motor 11 and the terminal OP1 becomes L level, the normally closed contact MC2b is held in the open state, so the electromagnetic contactor MC1 is not excited. Demagnetized state is maintained. Therefore, the transport vehicle 3 does not accidentally travel while the lifting device 10 is operating.

As described above, in this embodiment, the electronic thermal originally provided in the inverter 16 can be used to prevent the traveling motor 9 and the driving motor 11 from continuing to operate in an overloaded state. Therefore, it is not necessary to attach a thermal relay to one of the motors, and the cost is reduced. Further, in this embodiment, as a detection means for detecting which of the two motors 9 and 11 is in the ON state,
Normally open contact of electromagnetic contactor MC1 for driving traveling motor 9
Since it uses MC1a, the cost will be lower.

The present invention is not limited to the above embodiment, but may be embodied as follows, for example. (1) The normally open contact MC2a of the electromagnetic contactor MC2 may be connected between the input terminal TH and the contact input common terminal SD instead of the normally open contact MC1a of the electromagnetic contactor MC1. in this case,
When the normally open contact MC2a is held in the closed state, the CPU 24 determines that the drive motor 11 is in the on state, selects the overload cutoff reference value B as the overload cutoff reference value, and opens the normally open contact.
When MC2a is open, the overload cutoff reference value A is selected as the overload cutoff reference value.

(2) The input terminal TH is set to 2 in the inverter 16.
One (TH ₁ , TH ₂ ) is provided (not shown), and one input terminal T
Connect the normally open contacts MC1a between H ₁ and the contact input common terminal SD, the other input terminal TH ₂ and the contact input common terminal S
A normally open contact MC2a may be connected to D. In this case, correspond to the closed state of normally open contact MC1a and normally open contact MC2a.
Since the signal is input to the PU 24, the motor in the ON state can be specified more reliably.

(3) Instead of the contact of the electromagnetic contactor for driving the motor, as the detection means for detecting whether or not each motor is in the ON state, the contact of the relay that is excited and deenergized corresponding to the driving of the motor is used. May be used. For example, by changing the excitation / demagnetization circuit 23, as shown in FIG. 4, the bogie controller 15 is provided with an open collector output terminal OP3, and the normally open contact CR1a is provided.
And relay CR between normally closed contact MC1b and terminal OP3
Connect two. And normally open contact CR1a and normally closed contact MC1b
Between normally open contact MC2b and normally closed contact of relay CR2
Connect CR2a. Further, the normally open contact CR2a of the relay CR2 is connected between the contact input common terminal SD and the input terminal TH (not shown). In this case, when the traveling motor 9 is in the ON state, the relay CR2 is excited and its normally open contact CR2a is maintained in the closed state, and when the driving motor 11 is in the ON state, the relay CR2 is demagnetized and normally opened. Contact CR2a is held open. Therefore, the continuous operation of the motor in the overloaded state is prevented as in the above embodiment. Further, in this case, since the contact of the electromagnetic contactor for driving the motor is used for another circuit, there is no problem even in a state where there is no spare contact.

(4) The emergency stop relay CR1 and its normally open contact CR1a may be omitted. (5) When the motor in the ON state is overloaded, the PWM circuit outputs a command signal for reducing the load on the motor, for example, a command signal for reducing the power supplied to the motor, instead of outputting a stop command from the CPU 24. 28 may be output. In this case, the traveling or the elevating / lowering movement of the elevating table 5 can be performed in a state where the traveling speed or the ascending / descending speed is reduced, and the desired work can be completed even if it takes some time.

(6) The present invention is not limited to the overhead traveling type transport device 1, but may be applied to another device in which a plurality of motors that are not driven at the same time are shift-controlled by one inverter. When there are three or more motors, the CPU sends a signal based on the opening and closing of the normally open contact of the electromagnetic contactor for driving each motor, as in (2).
A configuration for outputting to 24 is preferable.

Inventions other than those described in the claims that can be grasped from the respective embodiments and modifications will be described below together with their effects. (1) In the invention according to claim 1, when the calculation result of the calculation means reaches the overload cutoff reference value of the motor in the ON state, a command to reduce the power supplied from the control means to the motor. Output a signal. In this case, it is possible to prevent the continuous operation of the motor in the overloaded state and to continue the work.

[0038]

As described in detail above, the first to fourth aspects of the invention are described.
According to the invention described in (1), overload protection of a plurality of motors whose shifts are controlled by the inverter can be performed by using the electronic thermal equipped in the inverter, and the cost is low compared to the case where the thermal relay is provided. Become. Claim 2
According to the invention described in (1), since the contact of the relay for driving the motor is used as the detection means, the cost becomes lower. According to the third aspect of the invention, continuous operation of the motor in the overloaded state is reliably prevented.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an embodiment embodying the present invention.

FIG. 2 is a schematic side view of the overhead traveling transfer device.

FIG. 3 is a partially cutaway schematic plan view of the overhead traveling transfer device.

FIG. 4 is a circuit diagram of a modified example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Ceiling traveling type conveyance device, 9 ... Traveling motor, 10 ... Elevating device, 11 ... Elevating device driving motor, 16 ... Inverter, 24 ... Central processing unit (CPU) as selecting means, arithmetic means and control means, 26 ... Current detection circuit as current detection means, 27 ... Storage device as storage means, MC
1, MC2 ... Electromagnetic contactor as motor drive relay,
MC1a ... Normally open contact as a detection means.

Claims (4)

[Claims] 1. A device for controlling a shift of a plurality of motors that are not driven simultaneously by a single inverter, and a detection means for detecting whether or not each motor is in an ON state, and an overload for each motor. A storage unit that stores a cutoff reference value, a selection unit that selects an overload cutoff reference value corresponding to a motor in an ON state from a plurality of overload cutoff reference values stored in the storage unit, and an inverter Calculating means for calculating the load state of the motor in the on state based on the output signal of the current detecting means; and the motor when the calculation result of the calculating means reaches the overload cutoff reference value of the motor in the on state. And a control means for outputting a command signal for reducing the load on the motor. 2. The motor drive control device according to claim 1, wherein the detection means is a contact of a relay for driving each motor. 3. The motor drive control device according to claim 1, wherein the command signal is a stop command signal for the motor. 4. The motor drive control device according to claim 1, wherein the device is an overhead traveling transfer device equipped with a traveling motor and a lifting device driving motor.