JPH044793A - Speed controller for industrial machine including hoisting device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a speed control device for industrial machinery such as a hoisting device, and enables inexpensive and highly accurate control.

[Conventional technology]

BACKGROUND ART Hoisting devices such as hoists generally use an induction motor (often wound type) as a drive source (main motor). As an unconventional method for controlling the speed of this main motor, there is the following method.

■ Method of using a thruster brake (push machine brake) for speed control A thruster brake is provided that applies brake torque to the main motor, and the main motor's rotation is controlled by feeding back the secondary frequency of the main motor and driving the push machine motor. Controlling the main motor's rotation speed by controlling the primary voltage applied to the main motor @ Inverter control method By controlling the frequency and voltage applied to the main motor ,
Controlling the rotation speed of the main motor [Problem to be solved by the invention] The speed control thruster brake described above has a simple control circuit configuration and is cheap, but the control accuracy is low.
(It can only reach a certain low speed of about 30% of the rated speed.) It also had the disadvantage of not being able to perform long slow soft starts and soft stops.

The method of controlling the primary voltage of the main motor has high control accuracy, but is expensive, requires a dedicated speed detector for the hoisting device, and has the disadvantage that operation becomes difficult in the event of a failure. there were.

The above-mentioned inverter control system has high control accuracy and can control speed over a wide range, but large-capacity models are expensive and have the disadvantage of being nearly impossible to operate in the event of a failure (even if possible, only full-speed operation). there were.

This invention solves the drawbacks in the conventional techniques, and
The present invention aims to provide a speed control device for industrial machinery such as a hoisting device that is inexpensive and capable of highly accurate speed control.

[Means to solve the problem]

The present invention includes a main motor using an induction motor, a thruster brake that applies a brake torque to the rotation of the main motor, a speed command means that gives a speed command value of the main motor, and a speed that detects the speed of the main motor. comprising a detection means and an inverter device that outputs a drive voltage with a frequency corresponding to the difference between the speed command value and the speed detection value, and by driving the pusher motor of the thruster brake with the output voltage of the inverter device. , the speed of the main motor is controlled.

[For production]

This invention uses a thruster brake to enable highly accurate speed control. That is, a voltage having a frequency corresponding to the difference between the speed setting value and the speed detection value is outputted from the inverter device to drive the pusher motor of the thruster brake. That is, when the speed of the main motor is faster than the set value, the output frequency of the inverter device becomes smaller and the pusher motor decelerates. As a result, the push-up blade becomes smaller, the brake torque becomes larger, and the main motor is decelerated. Conversely, when the speed of the main motor is slower than the set value, the output frequency of the inverter device increases and the pusher motor accelerates. As a result, the push-up blade becomes larger, the brake torque becomes smaller, and the main motor is accelerated.

In this way, the set speed can be controlled with high precision, and multi-step or stepless speed control is possible. In addition, by gradually changing the set value, long-term soft start and soft stop are possible. Moreover, since the inverter device only needs to have the capacity to drive the thruster brake, it can be small and inexpensive, and is particularly effective when equipped with a large-capacity main motor. Furthermore, by attaching this inverter device to a device equipped with a thruster brake, it can be applied to existing devices with simple modification.

Note that if the main motor is constituted by a wound induction motor and the speed of the main motor is detected based on its secondary output frequency, a separate speed detection means is not required.

In addition, the non-inverter control system is further provided with a non-inverter control system that switches and controls a rated operation in which the primary side input of the main motor is applied to the pusher motor and a low-speed operation in which the secondary side output of the main motor is applied to the pusher motor. If the system and the inverter control system that provides the output of the inverter device to the pusher motor are configured to be switchable by a control mode changeover switch, even if the inverter device fails, control can be performed by the non-inverter control system. Furthermore, such a configuration can be easily realized by adding the inverter control system and changeover switch of the present invention to a conventional device equipped with a thruster brake.

〔Example〕

FIG. 1 shows an embodiment in which the present invention is applied to an existing hoisting device such as a hoist equipped with a thruster brake. - The area within the dashed line 10 is the inverter control system added according to the present invention, and the area outside the dashed line 10 is the conventional non-inverter control system 12.

The power supply 14 is the power supply for this device, and is usually a three-phase AC power source of 400/400 mA.
A 440V or 200/220V 50/60Hz power supply is used.

The main motor 16 is used for winding up and down, and is an induction motor. The primary winding of the main motor 16 has a power supply 14
A secondary resistor 18 is connected to the secondary winding. Contactors 20a, 20b, 20 of secondary resistor 18
By sequentially applying c, the motor torque becomes larger and the rotational speed becomes faster. The secondary frequency of the main motor 16 corresponds to its rotational speed; when the rotational speed is high, a low frequency is output, and when the rotational speed is low, a high frequency is output.

The contactors 22a and 22b are used to switch the direction of rotation of the main motor 16 between normal rotation and reverse rotation, and when the contactor 22a is turned on, the motor rotates in the normal direction, and when the contactor 22b is turned on, it is rotated in the reverse direction.

Reference numeral 24 denotes a holding electromagnetic brake, which brakes the rotation of the main motor 16 by means of a contactor 26.

That is, when the contactor 26 is turned on, the brake is opened and the main motor 16 can rotate, and when the contactor 26 is turned off, the brake is closed and the main motor 16 is stopped.

Reference numeral 28 denotes a pusher motor. When the rotational speed of the pusher motor increases, the pusher moves up and opens the brake, reducing the brake torque and increasing the rotational speed of the main motor 16. Further, when the rotational speed becomes low, the push-up machine lowers and closes the brake, and the brake torque becomes large and the rotational speed of the main motor 16 becomes low.

The contactors 30 and 32 are for high/low speed switching in non-inverter control, and when operated to one notch, the contactor 30 is turned on and the contactor 32 is turned off, and the secondary frequency of the main motor 16 is changed to the contactor 30, Matching transformer 34 (main motor 16
is applied to the pusher motor 28 via the contact 36a of the control mode changeover switch 36, and the main motor 16 rotates at a constant low speed. Furthermore, when operated by two or more notches, the contactor 30 is turned off, the contactor 32 is turned on, the power frequency is applied to the pusher motor 28 via the contactor 32 and the contact 36a of the control mode changeover switch 36, and the thruster brake is turned off. will be released. Then, the secondary resistor contactors 20a, 20b, and 20c are sequentially turned on in accordance with the notch, and the switching 30.32 is performed by the internal contact opening/closing operation in conjunction with the notch operation by the controller 40.

The controller 40 includes speed command means for commanding the speed at the time of one notch, either in common with the notch operator or separately, and outputs a voltage corresponding to the operation. this is,
For example, 15%, 25%, 50%, 10 of the rating of 1 notch.
If 0% is indicated, 0.75V and 1
, 25V.

2.5V, 5. It can be configured to output OV.

The FV (frequency/voltage) converters 4 and 2 are means for detecting the speed of the main motor 16, and as shown in FIG.
Outputs a voltage proportional to the secondary frequency of 6 (inversely proportional to rotation speed).

Since the output of the F/V converter 42 is low speed and high output, the voltage converter 44 reverses the voltage to use it as speed feedback, and also inputs the speed feedback input of the inverter device 46. It functions to adjust the voltage value (for example, 0 to 5V). voltage converter 4
The input/output relationship of 4 is shown in FIG. 2(b). voltage converter 4
If the output of 4 is lowered to, for example, 0 to 2.5V, the control accuracy will deteriorate, but hatching can be prevented. Although it is possible to control the pusher motor 28 only by commands from the controller 40 without speed feedback, highly accurate control becomes possible by providing speed feedback.

The inverter device 46 determines the deviation between the speed command value Vp from the controller 4o and the speed detection value Vd from the voltage converter 44, and outputs a drive voltage VD having a frequency (or frequency and voltage value) according to this deviation. . This inverter device 46 is small enough to drive the pusher motor 28, for example, on the order of several hundred watts.

Control mode changeover switch 36 is for non-inverter control system 12
This is a switch for switching between control by the inverter control system and control by the inverter control system. Normally, it is connected to the contact 36b side to perform control by the inverter control system 10, and in the event of a failure of the inverter device 46 etc., it can be switched manually (by the controller 40).
Alternatively, it is automatically connected to the contact 36a side and controlled by the non-inverter control system 12.

Note that when controlling by the inverter control system 10, when the secondary resistor contactor 20c is turned on, the main motor 1
Since the secondary side frequency output voltage of No. 6 is O and the torque is too large to be controlled, the secondary resistor contactor 20c is not turned on.

The operation of the apparatus shown in FIG. 1 will be explained. When stopped, both the holding electromagnetic brake 24 and the thruster brake are closed, and both brake the main motor 16. When starting operation, the control mode changeover switch 36 is connected to the inverter control system 10 (on the contact 36b side). When the contactor 26 is turned on by operating the controller 40, the holding electromagnetic brake 24 is released and the main motor 16 becomes rotatable. When the controller 40 is operated one notch, the secondary resistor contactors 20a, 20b.

20c is turned off. Turn on the contactor 22a for forward rotation (upward rotation), and turn on the contactor 22a for reverse rotation (downward rotation).
Turn on b.

When the speed command value Vp is given by the controller 40, the inverter device 46 outputs a driving voltage VD having a frequency according to the deviation from the speed detection value Vd. At the beginning of startup, main motor 1
Since speed 6 is O, the deviation is large and a high frequency drive voltage VD is output from the inverter device 46. As a result, the pusher motor 28 rotates at high speed, pushing up the pusher, weakening the brake torque, and accelerating the main motor 16. As the speed command value Vp approaches, the deviation from the speed detection value Vd becomes smaller and the frequency of the drive voltage VD becomes lower. As a result, the pusher motor 28 gradually decelerates, increases the brake torque, and balances when the speed matches the command speed.

By gradually increasing the speed command value Vp of the controller 40, a gentle (for example, 30 seconds or more) soft start can be realized.

Further, by gradually lowering the speed command value Vp, a gradual soft stop can be achieved. When the speed command value Vp reaches the maximum, the output frequency of the inverter device 46 increases,
The pusher motor 28 is rotated at high speed, the brake torque is zero, and the main motor 16 is accelerated.

After that, when the main motor 16 requires higher torque, the notch can be raised, and the secondary resistor contactor 20a,
20b are sequentially introduced.

If the inverter device 46 fails, the control mode changeover switch 36 is connected to the contact 36a side, and the non-inverter control system 12 can perform emergency operation. That is, when a low speed command is issued (1 notch), the switch 30 is on and the switch 32 is off. As a result, the secondary output of the main motor 16 is applied to the pusher motor 28 via the switch 30, matching transformer 34, and switch 36, and the speed is controlled by the thruster brake as in the conventional art. Further, when the number of notches is two or more, the switch 30 is turned off and the switch 32 is turned on.

Also, depending on the notch, a secondary resistor contactor 20a.

20b and 20c are turned on sequentially. As a result, the pusher motor 28 is driven at the primary frequency of the main motor 16, the brake torque becomes 0, and the main motor 16 is operated at a speed corresponding to the notch.

[Modification] In the embodiment described above, the present invention is applied to one notch, but it can also be applied to upper notches.

In the embodiments described above, a wound type induction machine is used as the main motor, but the present invention can also be applied to a main motor using various types of induction machines such as a high-resistance squirrel cage type. If secondary side output frequency information cannot be obtained, a separate speed detection means may be used.

In the embodiment described above, the present invention is applied to hoisting/up/down control of a hoisting machine, but it can also be applied to travel control and other speed control of various industrial machines.

〔Effect of the invention〕

As explained above, according to the present invention, a voltage with a frequency corresponding to the difference between the speed setting value and the speed detection value is output from the inverter device, and this drives the pusher motor of the thruster brake to control the speed. As a result, the set speed can be controlled with high precision, and multi-step or stepless speed control becomes possible. In addition, by gradually changing the set value, long-term soft start and soft stop are possible. Furthermore, since the inverter device only needs to have the capacity to drive the thruster brake, it can be small and inexpensive, and is particularly effective when equipped with a large-capacity main motor. Furthermore, by attaching this inverter device to a device equipped with a thruster brake, it can be applied to existing devices with simple modification.

Further, if the main motor is constituted by a wound induction motor and the speed of the main motor is detected based on its secondary output frequency, a separate speed detection means is not required.

Furthermore, the non-inverter control system switches between a rated operation in which the primary side input of the main motor is applied to the pusher motor and a low-speed operation in which the secondary side output of the main motor is applied to the pusher motor. If the system and the inverter control system that supplies the output of the inverter device to the pusher motor are configured to be switchable using a control mode changeover switch,
Even when the inverter device fails, it can be controlled by the non-inverter control system. Further, since the inverter control system and changeover switch of the present invention can be added to a device having such a configuration or a conventional thruster brake, it can be easily realized.

DESCRIPTION OF SYMBOLS 10... Inverter control system, 12... Non-inverter control system, 16... Main motor, 28... Thruster brake pusher motor, 36... Control mode changeover switch, 42... Speed detection Means, 46...Inverter device, Vp...Speed command value, Vd...Speed detection value, VD
...Driving voltage.

Applicant: Ishikawajima Harima Heavy Industries Co., Ltd. Ishikawajima Transport Co., Ltd.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention. FIG. 2 is an input/output characteristic diagram of the F/V converter 42 and voltage converter 44 shown in FIG.

Claims (3)

[Claims] (1) A main motor using an induction motor, a thruster brake that applies a brake torque to the rotation of the main motor, a speed command means that provides a speed command value of the main motor, and a speed detector that detects the speed of the main motor. and an inverter device that outputs a drive voltage with a frequency corresponding to the difference between the speed command value and the speed detection value, and by driving the pusher motor of the thruster brake with the output voltage of the inverter device, A speed control device for an industrial machine such as a hoisting device, characterized in that it controls the speed of the main motor. (2) The hoisting device according to claim 1, wherein the main motor is a wound induction motor, and the speed detection means detects the speed of the main motor based on a secondary output frequency of the main motor. Speed control devices for industrial machinery such as. (3) Further comprising a non-inverter control system that switches and controls a rated operation in which the primary input of the main motor is applied to the pusher motor and a low speed operation in which the secondary output of the main motor is applied to the pusher motor. 3. An industrial machine such as a hoisting device according to claim 2, wherein said non-inverter control system and an inverter control system that provides the output of said inverter device to said pusher motor are configured to be switchable by a control mode changeover switch. Speed control device.