JP2000344351A - Bucket elevator driving method for continuous unloader - Google Patents

Abstract

(57) [Problem] To stably start a bucket elevator of a continuous unloader for discharging a load from a hold. A continuous unloader having a bucket elevator that scrapes and discharges a cargo in a hold by driving a chain mounted with a bucket by a driving sprocket, wherein two guides are individually provided to the driving sprocket via a speed reducer. The motors are connected and these are connected to individual motor drive circuits 34
A, the induction motor is vector controlled and converts the torque current and magnetic flux based on the primary current and the primary voltage of the 32AF at 34B, primary current when applying a low DC voltage V _D to the induction motor 32AF at start By detecting I _D1 , measuring the primary resistance r _1, and correcting the primary voltage drop based on the measured value, the influence of the primary resistance change during speed control is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bucket elevator driving apparatus and method for a continuous unloader for continuously scraping and carrying loads in a hold, and more particularly to a motor for controlling a bucket elevator by an AC variable speed apparatus. It is designed to be driven.

[0002]

2. Description of the Related Art A practical unloader of this type has been actively developed in recent years because it is easy to increase the size of the unloader. As a conventional bucket elevator driving device for a continuous unloader, for example, Japanese Unexamined Patent Publication No.
There is one described in JP-A-11-11688.

[0003] This conventional example is a continuous unloader having a bucket elevator that scrapes and discharges a load in a hold by driving a chain on which a bucket is mounted with a driving sprocket. The two induction motors are connected via a motor, and these are vector-controlled by separate motor drive circuits. At startup, the torque current target calculated by the target value calculation circuit in the motor drive circuit composed of one speed sensorless vector inverter There is disclosed a bucket elevator driving apparatus and method of a continuous unloader in which each induction electric motor is synchronously controlled based on a value, and after starting, an independent motor control circuit performs independent vector control.

[0004]

However, in the conventional bucket elevator driving apparatus for a continuous unloader described above, two induction electric motors that individually drive a pair of driving sprockets at the time of startup are replaced by one motor. Synchronous control of each induction motor based on the torque current target value calculated by the target value calculation circuit in the drive circuit prevents interference between the electric motors and performs stable drive control. The speed sensorless vector inverter detects the primary current and the primary voltage of the electric motor of the electric motor, performs magnetic flux and torque current conversion based on these, performs speed estimation calculation from the deviation of the torque current, For voltage, voltage drop correction based on the cable and motor primary resistance measured in advance is performed. There is an unsolved problem which will be described.

[0005] That is, during the cargo handling, the bucket elevator is interlocked when the ground conveyor is stopped.
The load may stop while the load is being loaded, and in the subsequent restart, an electromagnetic brake is provided on the output side of the electric motor to prevent reverse rotation of the bucket, and this electromagnetic brake is used after a predetermined torque is generated by the electric motor. I am trying to open it.

In such a situation in which the load changes suddenly due to the low speed immediately after startup and the release of the electromagnetic brake, an error in the primary resistance of the motor due to a change in the motor temperature greatly affects the speed estimation calculation accuracy. There is an unsolved problem in that the speed estimation calculation accuracy is reduced due to the influence of the ambient temperature, and starting may be difficult. Therefore, the present invention has been made by focusing on the unsolved problems of the above conventional example, and every time the bucket elevator of the continuous unloader is started,
An object of the present invention is to provide a bucket elevator driving method of a continuous unloader that can improve a speed estimation calculation accuracy at the time of starting by setting a motor constant and can perform stable starting.

[0007]

According to a first aspect of the present invention, there is provided a bucket elevator driving method for a continuous unloader, wherein a plurality of buckets are mounted between a pair of endless chains, and the endless chains are mounted on an upper end. Is stretched between a pair of driving sprockets disposed at the bottom and a scraping portion disposed at a lower portion through a bucket insertion cylinder hung at the end of the boom, and the driving sprocket is rotationally driven to scrape. A bucket elevator in which the load in the hold is scraped into the bucket and conveyed to the upper collecting section, and the sprocket of the bucket elevator is driven by an electric motor controlled by a vector control type AC variable speed device. In the bucket elevator driving method for the continuous unloader as described above, every time the electric motor is started, the AC variable speed device It is characterized in that the motor parameters of the serial motor and adapted to automatically adjust.

According to the first aspect of the present invention, the motor constant in the AC variable device is automatically adjusted every time the motor is started to drive the bucket elevator, thereby reducing the temperature dependence of the motor constant, particularly the primary resistance. It is possible to take account of this, and stable start-up of the bucket elevator can be ensured. Also, in the bucket elevator driving method for a continuous unloader according to claim 2, in the invention according to claim 1, the motor constant is a primary resistance of the motor, and a DC low voltage is applied to the primary side of the motor at startup. A primary side current value at the time of application is detected, a primary side resistance is calculated by dividing an applied voltage by the detected primary side current value, and a voltage drop correction of the AC variable speed device is performed based on the calculated primary resistance. It is characterized by doing so.

In the invention according to the second aspect, the primary resistance of the motor is automatically measured when the motor is started, and the voltage drop of the AC variable speed device is corrected based on the measured value. In this case, it is possible to reliably prevent the speed estimation calculation accuracy from being lowered due to the influence of the operating condition and the ambient temperature.

[0010]

Embodiments of the present invention will be described below. FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention. A continuous unloader 7 is driven by an electric motor (not shown) to roll on traveling rails 4a and 4b installed on a quay 1. A traveling frame 10 having driving wheels 9a and 9b is provided.

On the traveling frame 10, a swivel tower 11 having a conveyor 11a built therein for vertically transporting the scattered material therein for effect is provided at an angle of 125.degree. The hopper 12 is rotatably supported within the range, and a hopper 12 is fixedly disposed below the swirl tower 11.
A belt feeder 13 for dispensing a fixed amount toward is provided. At the falling position of the belt feeder 13, an in-machine conveyor 14 for transporting the scattered material to a position above the receiving belt conveyor 5 is provided. It is transferred onto the conveyor 5.

At the upper end of the swivel tower 11, a swivel boom 15 in which a belt conveyor 15a for transporting splinters is disposed is rotatably supported in a vertical plane. A balance weight 16 is provided on the opposite side. At both ends of the turning boom 15, inclined support links 17 and 18 are rotatably supported.
A link 19 parallel to the swiveling boom 15 is rotatably connected to a free end of 18 to form a parallel link, and a bucket elevator 20 extending in the vertical direction is fixed to the inclined support link 17 on the free end side.

The bucket elevator 20 has a cylindrical fixed frame 21 fixed to the support link 17 and a cylindrical column member 22 constituting an elevator shaft pivotally supported by the fixed frame 21.
2, a pair of front and rear chain drive sprockets 23A and 23B mechanically connected to each other by a drive shaft 23a are provided at the upper end of the column member 22, and the lower end is provided with an L. And a pair of endless chains 25A and 25B is extended so as to orbit around the sprockets 23A and 23B and the excavation portion 24 through the column member 22. , 25B, a number of buckets 26 are mounted at predetermined intervals to form a bucket conveyor.

The column member 22 is fixed to the fixed frame 2.
1 is rotated by a rotation drive mechanism such as a motor mounted on the motor 1 and the sprockets 23A and 23B are similarly rotated counterclockwise in FIG. 1 by a sprocket rotation drive mechanism including the motor. Here, as shown in FIG. 2, the sprocket rotation drive mechanism has speed reducers 27A and 27B connected to both ends of a drive shaft 23a, and the output side gears 28A and 28B are driven by the speed reducers 27A and 27B. The output side gear 28 is engaged with two input side gears 29AF, 29AR and 29BF, 29BR.
9BF and 29BR are electromagnetic brakes 30AF and 30A and 30BF and 30BR and torque limiters 31AF and 31A.
R and 31BF, 31BR are connected to the induction motors 32AF, 32AR and 32BF, 32BR in that order.

Each of the induction motors 32AF to 32BR is connected to motor drive circuits 34A and 34B constituting a control device via slip rings 33AF to 33BR, and is driven and controlled by these motor drive circuits 34A and 34B. These motor drive circuits 34A and 34B
Perform speed sensorless vector control as shown in FIG.

That is, the motor driving circuits 34A and 34
B is a torque current target value i based on the speed command value _Nref.
1T ^* and target value calculation circuits 35A and 35B for calculating the magnetizing current target value i _1M ^* , and the torque current target value i _1T ^* and the magnetizing current target value i _1M ^* output from the target value calculation circuits 35A and 35B. and the current detection value I ₁ from the later-described current sensor 38A is input, a subtracter 36AFT outputting these deviations, 36AFM; 36ART, 36AR
M and 36BFT, 36BFM; 36ART, 36AR
M and these subtractors 36AFT, 36AFM; 36AR
T, 36ARM and 36BFT, 36BFM; 36AR
T, the current vector calculation circuit 37AF the primary frequency omega ₁ and the output from the deviation signal and the target value computing circuit 34A and 34B output from 36ARM is input, 37AR and 37BF, and 36bR, these current vector computing circuit 36AF , 36AR, 36BF, and 37BR, the voltage-type pulse width modulation (PWM) inverter 38A that drives the induction motors 32AF, 32AR and 32BF, 32BR based on the three-phase current target values.
F, 38R and 38BF, 38BR.

Here, the target value calculation circuit 35A detects a three-phase current value of the inverter 38AF, converts the detected value into a single-phase current, and outputs the single-phase current.
And a voltage sensor 42AF for detecting a three-phase voltage value of the 8AF, converting the detected value into a single-phase voltage, and outputting the same. The current detection value I ₁ of the current sensor 41AF and the voltage sensor 42AF
Voltage detection value V ₁ of the can is supplied to the current-magnetic flux converter 43A for calculating a torque current I ₂ and the magnetic flux φ of the secondary current.

[0018] At this time, the voltage detection value V ₁ of the voltage sensor 42AF is multiplied by the multiplication circuit 44A the sum of the primary resistance r ₁ and cable resistance r _f as the motor constant to the current detection value I ₁ of the current sensor 41AF By doing so, a voltage drop correction value of the cable and the primary resistance of the electric motor 32AF is calculated and supplied to the subtractor 45A, and the subtractor 45A
, The voltage detection value V ₁ is subtracted and corrected, and the voltage correction value output from the subtractor 45A is supplied to the current / magnetic flux conversion circuit 43A.

Here, the primary resistance r of the motor 32AF
_{Since 1} is the operating condition of the bucket elevator 20 before starting, that is, immediately after the end of the previous operation of the bucket elevator 20, or the time has elapsed since the end of the operation, or changes due to the influence of the ambient temperature, Bucket elevator 2
It is automatically adjusted every time 0 is started. That is, the changeover switch 61 is interposed between the inverter 38AF and induction motor 32AF, on the output side of the one fixed contact ta inverter 38AF of the change-over switch 61, the other fixed contact tb is at a low DC voltage V _D Each of the movable contacts tc is connected to an induction motor 32AF. On the other hand, the current sensor 41
The current detection value I ₁ detected by the AF is used as the starting adjustment circuit 63.
The start-up adjusting circuit 63 fixes the movable contact tc of the changeover switch 61 when a bucket elevator pre-start signal CS of, for example, a logical value “1” is input from a control device that controls the continuous unloader. The contact is switched to the contact tb side, and in this state, the primary current value I _D1 when the DC low voltage V _D from the DC constant voltage source 62 detected by the current sensor 41AF is applied is read, and the DC low voltage V _D is primary The primary resistance r ₁ of the induction motor 32AF is calculated by dividing by the current value I _D1 , the calculated primary resistance r ₁ is set in the multiplying circuit 44A, and when the pre-start signal CS becomes the logical value “0”, the switching is performed. The movable contact tc of the switch 61 is returned to the fixed contact ta side. In startup adjustment circuit 63 is performed to adjust the primary resistance r _1, for example 0.01% resolution.

Further, the fluctuation of the secondary resistance of the induction motor 32AF does not affect the magnetic flux and the torque. The current-flux transformation torque current I ₂ which is output from the circuit 43A are supplied to a subtracter 46A ^{to *} the torque current target value i _1Ta entered, deviation rate estimation circuit therebetween outputted from the subtracter 46A The speed estimation value N _det is supplied to 47A and the speed estimation value N _det is calculated. The speed estimation value N _det and the speed command value N _ref are input to a subtractor 48A, and the difference between the two is input to a speed controller 49A. The torque current command value i _1TA is calculated by the unit 49A, and this is input to the adder 51A via the first-order lag filter 50A.

[0021] In the adder 51A, the torque current compensation value i _AT for securing the starting torque to the filter output of the first-order lag filter 47A adds the correction, the maximum torque value is limited to the addition correction value by the limiter 52A , _Whose output is the torque current target value i _1TA ^*
Output to 6ART. On the other hand, the speed estimation value N _det output from the speed estimation circuit 47A is
When the absolute value of the speed estimated value N _det is equal to or less than a preset value, the magnetic flux command value calculating circuit 53A calculates a constant secondary magnetic flux target value φ ₂ ^*, and calculates the speed estimated value. When N _det exceeds the set value, the speed estimation value N
_A secondary magnetic flux target value φ ₂ ^* that decreases as _det increases in the positive and negative directions is calculated, and this secondary magnetic flux target value φ ₂ ^* is input to the subtractor 54A.

The subtractor 54A has the current / flux conversion.
The magnetic flux φ output from the conversion circuit 43A is input,
This and the secondary magnetic flux target value φ_Two ^*Deviation from the magnetic flux controller 55
A from the magnetic flux controller 55A
Value i_1MA ^*Is output, and this is subtracted by the subtractors 36AFM and 3
6ARM. Further, the output from the limiter 52A
Target torque current value i_1TA ^*Is the slip operation circuit 56
A, and the torque calculation circuit 56A
Standard value i_1TA ^*Based on the slip angle frequency ω_SIs calculated.
And the speed estimation value N of the speed estimation circuit 47A. _detAnd the adder
57A, the primary frequency ω₁Calculate
The current vector calculation circuits 37AF and 37AR
To supply.

The other target value calculation circuit 35B also has an adder 51.
A target value calculation circuit 35
A The torque current target value i _1TA ^{* of A} is input, and the gain of the speed controller 49B is
The gain is set to “0” at the start of “0”, and the gain in the normal state thereafter is set to be smaller than the gain of the speed controller 49A of the target value calculation circuit 35A. 35A has the same configuration as that of the target value calculation circuit 35A, and the portions corresponding to the target value calculation circuit 35A are represented by replacing the symbol A with the symbol B, and the detailed description thereof is omitted.

The current vector calculation circuits 37AF-3
In 7BR, the input primary frequency ω ₁ is integrated to determine φ ₁ as the relative electrical angle of the rotating magnetic field axis with respect to the stator winding axis, and the input torque current deviation Δi _T and magnetization current deviation Δi Based on _M , coordinate conversion from the rotating magnetic field coordinate system to the stator winding coordinate system is performed, and two-phase / three-phase conversion is performed to perform voltage-type pulse width modulation inverters 38AF-38.
A target current value to be supplied to the BR is calculated, and this is output to the inverters 38AF to 38BR.

Voltage source pulse width modulation inverters 38AF-
38BR are current vector calculation circuits 37AF to 3AF
Induction motor 3 according to the current target value output from 7BR
The three-phase power supplied to 2AF to 32BR is controlled. Returning to FIG. 1, the fixed frame 21 has the sprockets 23A, 23B below the sprockets 23A, 23B.
A chute 51 is formed to receive the debris falling from the bucket 26 inverted at 23B, and the debris guided by the chute 51 is rotated by a rotary feeder 52 disposed at the lower end thereof.
Is transferred to the conveyor 15a in the turning boom 15.

The excavating portion 24 includes a support frame 61 rotatably supported at the lower end of the column member 22, a horizontal support frame 62 similarly rotatably supported at the lower end thereof, and left and right ends of the support frame 62. Chain 25A, 25B
The sprockets 63 and 64 are mounted on the horizontal support frame 62 by rotating the support frames 61 and 62 by a rotation drive mechanism such as a hydraulic motor.
Can be moved in the front-rear direction while maintaining the horizontal state.

Therefore, as shown in FIG. 1, the bucket elevator 20 is inserted into the hold A, the bucket 26 at the lower end of the horizontal support frame 62 is brought into contact with the scattered material 65 and scraped off. When the bucket 26 is turned upright at the position of the upper sprockets 23A and 23B, the scattered material inside the bucket 26 is moved through the chute 51 and the rotary feeder 52 to turn the boom 15.
Is transported to a conveyor 15a inside the rotating tower 11 and then lowered vertically by a conveyor 11a inside the swirling tower 11 to be temporarily stored in a hopper 12.

From the hopper 12, a fixed amount of paper is discharged by the belt feeder 13 in accordance with the carrying capacity of the receiving belt conveyor 5, and is transferred to the receiving and selling belt conveyor 5 via the in-machine conveyor 14. This operation is performed to move the bucket elevator 20 around the hold A, for example, so that the dust in the hold A is sequentially carried out.

Next, the operation of the above embodiment will be described with reference to a timing chart at the time of startup shown in FIG. Assuming that the continuous unloader is in a stopped state, in this state, the scraping unit 24 is inserted into the hold A as shown in FIG.
The bucket 26 at the lower end of the horizontal support frame 62 is
Set on 5

In this state, when the bucket elevator 20 is activated to start scraping off the dust 63, first, the electromagnetic brakes 30AF to 30BR are maintained in the operating state as shown in FIG. , in the control device which controls a total time t _1, when the operation start instruction to the oN state, in response to this, as shown in FIG. 4 (b), pre-boot control signal CS
Becomes a logical value "1", which is input to the startup adjustment circuit 63, whereby the movable contact tc of the changeover switch 61 is switched to the fixed contact tb side by the startup adjustment circuit 63, and the DC constant voltage source 62 low DC voltage V _D is applied to the primary side of the induction motor 32AF of. In this Yo, by applying a low DC voltage V _D to the induction motor 32AF, it is possible to measure the primary resistance r ₁ without being influenced by the impedance of the primary winding of the induction motor 32AF.

A DC low voltage V _{D is} applied to the induction motor 32AF.
Is applied, the startup adjustment circuit 63 reads the primary current value I _D1 detected by the current sensor 41AF, and converts the DC low voltage V _D set in the DC constant voltage source 62 into the primary current value I _D.
Is divided by _D1 calculates the primary resistance r _1, calculated primary resistance r
₁ is set in the multiplication circuit 44A. At the time t ₂ after a few seconds,
As shown in FIG. 4B, the pre-startup control signal CS output from the control device returns to the logical value “0”, and the movable contact tc of the changeover switch 61 is fixed by the start-up adjusting circuit 63 accordingly. It returns to the contact point ta side.

At the same time, with the gain of the speed controller 49B of the target value calculation circuit 35B set to "0", the speed command value _Nref is set to the target speed 1 as shown in FIG.
The initial excitation state is about 0%. At this time, since the gain of the speed adjuster 49B of the target value calculation circuit 35B is set to “0”, the torque current command value output from the speed adjuster 49B becomes zero and is input to the adder 51B. Target current value i from the target value calculation circuit 35A
_1TA ^* is output as it is as the torque current target value i _1TB ^* .

As a result, based on the torque current target value i _1TA ^* calculated by the target value calculation circuit 35A, the current vector calculation circuits 37AF-37BR convert the inverters 38AF-3
By calculating and outputting the target current value for 8BR, each of the induction motors 32AF to 32BR is started in synchronization, and a stable start can be performed without causing mutual interference.

[0034] Then, outputs a torque command is set to about 10% with respect to the normal torque command at the time, as shown in FIG. 4 (d) at t ₃ after a predetermined time (e.g., 1 second) has elapsed,
Then outputs a brake release command to the released state this for electromagnetic brake 30AF~30BR as shown in FIG. 4 (e) at time t _4, immediately after the electromagnetic brake release at t ₅ after the passage of the brake release delay time As shown in FIG. 4 (f), a torque compensation i _AT is generated in order to secure the starting torque of, and this is input to the adder 51A.

Then, the electromagnetic brakes 30AF to 30BR
Are in the released state, the induction motors 32AF to 3AF
2BR is transmitted to the drive shaft 23a via the reduction gears 27A and 27B, and thereby the sprocket 2
3A and 23B start rotating at a low speed, and the
Scraping of the debris 65 by the bucket 26 is started,
In response to this, the speed estimation value N _det calculated by the speed estimation circuits 47A and 47B increases in accordance with the low-speed driving state as shown in FIG.

This low-speed state is maintained until time t ₆ , during which the induction motors 32 AF to 3 AF to 3 AF are maintained.
An impact caused by inertia torque generated when a backlash of the 2BR drive system is absorbed is suppressed. Then, at time t ₆
By gradually increasing the speed command value N _ref as shown in FIG. 4 (c) in the velocity estimation value N _det increases as shown in FIG. 4 (g), the speed command value at time t ₇ N _ref If There reaches the target speed, velocity estimates at a later time t ₈ N _{de t}
Reaches the target speed.

When the estimated speed value N _det reaches the target speed, the gain of the speed adjuster 49B of the target value calculating circuit 35B is switched to the normal gain smaller than the gain of the speed adjuster 49A of the target value calculating circuit 35A. Can be Therefore, the target value computing circuit 35B, will be the torque current command value independent based on the speed command value N _ref is calculated, this target value computing circuit 35A torque current target value calculated by the i _1Ta ^* is By being added as the torque compensation, a torque current target value i _1TB ^* is calculated, whereby the induction motors 32BF and 32BR are connected to the induction motor 32A.
By being driven and controlled independently of F and 32AR,
During normal load balancing, the drive is controlled by the torque current target value i _1TA calculated by the target value calculation circuit 35A.
When the loads on the sprockets 23A and 23B are different, these are controlled independently to prevent the occurrence of load imbalance.

In addition, the gain of the speed controller 49B of the target value calculation circuit 35B is set to a value smaller than the gain of the speed controller 49A of the target value calculation circuit 35A. Since only the P control is performed on the value calculation circuit 35B side, the sprocket 23
When the load balance between A and 23B is lost and a speed deviation occurs, the correction operation can be performed without interference between the two.

Therefore, the primary resistance r of the induction motor
When you start actually bucket elevators 20 ₁ by the activation method of automatically adjusting, as shown in FIG. 5, by moving at t ₁₂ to the low speed holding state, the torque command value in the motor drive circuit 34A and 34B There were increases in substantially synchronized, while releasing the electromagnetic brake 30AF~30BR at time t _13, by adding a torque compensation input i _aT, torque both increased in the motor drive circuit 34A and 34B, in this case Scrap 7 scraped into bucket 26
5 can be generated against the reverse rotation torque caused by its own weight, which is generated when the gear 5 is accommodated, whereby the drive sprockets 23A and 23B are driven to rotate, and the speed estimation in each of the motor drive circuits 34A and 34B at this time is performed. becomes precise value estimated speed N _det based on the current value I ₁ and the voltage value V ₁ of the in circuit 47A and 47B is corresponding to the speed command, stable startup without causing a velocity anomaly performed, the time t ₁₄ It was confirmed that the estimated speed value also increased steadily with the increase in the speed command value at.

Incidentally, the primary resistance r _{1 of the} induction motor 32AF when starting the bucket elevator 20 as in the conventional example.
If the prevent automatic adjustment, if representing the primary side resistor r ₁ in percent impedance, the actual value (about 3.5
Respect to 4.0%), even deviations below 0.2%, as shown in FIG. 6, the torque command rises at time t _22, as well as an electromagnetic brake the released state at time t _23, the torque compensation input Is added, at time t ₂₄ , the speed estimation value of each speed estimating circuit indicates an abnormal value.
It was confirmed that the torque calculation was stopped at ₂₅ , and the starting of the bucket elevator 20 was stopped, and there was a case where stable starting could not be performed.

On the other hand, in the present embodiment, the primary resistance r ₁ of the induction motor 32AF is measured at the time of start-up, and is automatically adjusted by the multiplying circuit 44A for correcting the voltage. Starting in response to changes in the primary resistance r ₁ activation by previous operating conditions or ambient temperature of the elevator 20 can be performed, it is possible to ensure stable start of the bucket elevator 20.

In addition, each induction motor 32AF, 32AR
, 32BF, and 32BR are controlled by the speed sensorless vector control, so that slip rings 33AF, 33AR and 33BF, 3BF are connected between the control circuit and the induction motor.
Even in the case of connection by 3BR, the accuracy of torque calculation can be improved, and more accurate speed control can be performed.

Thereafter, while controlling the excavation depth in the excavation section 24, the bucket elevator 20 is moved while the longitudinal direction of the excavation section 24 and the ship wall are kept substantially perpendicular to scrape out debris. . On the other hand, when scraping off debris at the corner portion of the hold A, the respective parts such as the swiveling boom 15 are operated to rotate the bucket elevator 20 and the excavating section 2.
4 is rotated along the corner, and if necessary, the support frames 31 and 32 are rotated to move the excavated portion 24 in the longitudinal direction, thereby scraping off the dust at the corner.

In the above embodiment, the case where the changeover switch 61 is switched by the start-up adjustment circuit 63 has been described. However, the present invention is not limited to this. May be controlled, as long as the primary resistance r ₁ of the induction motor can be automatically adjusted when the bucket elevator 20 is started.

In the above embodiment, the case where the target value calculation circuits 35A and 35B perform speed estimation calculation based on the deviation between the torque current value I ₂ and the torque current target values i _1TA ^* and i _1TB ^* will be described. However, the present invention is not limited to this. The back electromotive force calculation circuit calculates the induced voltage based on the current detection value I ₁ and the voltage detection value V ₁ , and calculates the speed estimation value based on the calculated electromotive force. The electrical angle φ ₁ of the next rotation axis relative to the stator winding axis may be calculated using the voltage model method. Speed sensorless vector control using a speed-adaptive secondary magnetic flux observer for estimating the intersecting magnetic flux can also be applied.

Further, in the above embodiment, two induction motors 3 are provided for each of the sprockets 23A and 23B.
Although the case where the drive system is constituted by 2AF, 32AR and 32BF, 32BR has been described, the present invention is not limited to this, and three or more induction motors may be applied to each of the sprockets 23A and 23B. . Furthermore, in the above embodiment, each induction motor 32A
F, 32AR and 32BF, 32BR are controlled by speed sensorless vector control. However, the present invention is not limited to this, and each induction motor 32AF, 32AR is controlled.
, 32BF, and 32BR may be detected by a pulse encoder or the like, so that normal vector control may be performed. In this case, if a slip ring is used, torque calculation accuracy due to noise is reduced. It is preferable to wirelessly transmit the detected rotational speed value to the control circuit using a motor or the like, and it is also possible to apply a synchronous motor instead of the induction motor. In this case, too, it is preferable to perform vector control of each synchronous motor. I just need.

[0047]

As described above, according to the first aspect of the present invention,
According to the bucket elevator driving method of the continuous unloader according to the present invention, every time the motor is started to drive the bucket elevator, by automatically adjusting the motor constant in the AC variable device, the temperature dependence of the motor constant, particularly the primary resistance. Can be taken into account, and the effect that stable activation of the bucket elevator can be ensured can be obtained.

Further, according to the bucket elevator driving method of the continuous unloader according to the second aspect, the primary resistance of the motor is automatically measured when the motor is started, and the voltage of the AC variable speed device is determined based on the measured value. By performing the descent correction, an effect is obtained that the accuracy of the speed estimation calculation can be reliably prevented from lowering due to the influence of the operating condition before the start and the ambient temperature.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an overall configuration of a continuous unloader to which the present invention can be applied.

FIG. 2 is a configuration diagram of a bucket elevator drive unit showing one embodiment of the present invention.

FIG. 3 is a block diagram illustrating an example of a control device in FIG. 2;

FIG. 4 is a time chart for explaining the operation of the embodiment.

FIG. 5 is a time chart showing a state of each unit when starting according to the embodiment.

FIG. 6 is a time chart for explaining the occurrence of an abnormality when the primary resistance is not adjusted from the start.

[Explanation of symbols]

 Reference Signs List 1 pier 7 continuous unloader 15 boom 20 bucket elevator 23A, 23B drive sprocket 24 excavation unit 25A, 25B chain 26 bucket 27A, 27B reducer 32AF-32BR induction motor 33AF-33BR slip ring 34A, 34B motor drive circuit 35A, 35B Value calculation circuit 37AF-37BR Current vector calculation circuit 38AF-38BR Voltage type pulse width modulation inverter 49A, 49B Speed controller 61 Changeover switch 62 DC constant voltage source 63 Start-up adjustment circuit

Claims (2)

[Claims] 1. A plurality of buckets are mounted between a pair of endless chains, and the endless chains are hung at the end of a boom between a pair of driving sprockets provided at an upper portion and a scraping portion provided at a lower portion. A bucket elevator is provided which is stretched through the bucket insertion cylinder and rotatably drives the driving sprocket so as to scrape the load in the hold in the bucket at the scraping unit and convey it to the upper collecting unit. In the bucket elevator driving method of the continuous unloader, wherein the sprocket of the bucket elevator is driven by an electric motor controlled by a vector control type AC variable speed device, every time the electric motor is started, the AC variable speed device A method of driving a bucket elevator of a continuous unloader, wherein the motor constant of the motor is automatically adjusted. Law. 2. The motor constant is a primary resistance of the motor, detects a primary current value when a low DC voltage is applied to a primary side of the motor at the time of starting, and detects a primary current that detects the applied voltage. 2. The bucket elevator drive of a continuous unloader according to claim 1, wherein a primary-side resistance is calculated by dividing by a value, and a voltage drop correction of the AC variable speed device is performed based on the calculated primary resistance. Method.