JP2877591B2 - Shaft hoist control unit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for controlling the operation of a shaft hoist, and in particular, to significantly increase the operating power factor during power running operation without increasing the risk of commutation failure during regeneration. The present invention relates to a shaft hoist control device to be obtained.

[0002]

2. Description of the Related Art In general, a shaft hoist, as shown in FIG.
It controls the DC motor 6 that drives the drum 30 that hoists or lowers via the ropes 33 and 34.

That is, when hoisting a load, a load is loaded on the skip 31, and the skip 32 is empty. At this time, the drum 30 rotates clockwise. Initially, the torque generated by the DC motor 6 is upward (positive torque),
At the same time as the skip 31 is hoisted, the skip B32 is lowered, and at a certain point, the total load on both sides of the drum 30 (the sum of the skip weight, the product load, and the rope weight).
Are balanced. After this point, the total load becomes unbalanced in the opposite direction, so that the DC motor 6 must generate a torque (negative torque) in the opposite direction.

FIG. 3 is a diagram showing an example of the relationship between the rotation direction and the torque described above. That is, at the time of startup, the torque becomes a positive torque (power running operation), and after the equilibrium point A23, the torque becomes a negative torque (regenerative operation). Therefore, the thyristor converters 11 that control the DC motor 6 for the shaft hoist must be connected in antiparallel to each other.

FIG. 4 is a circuit diagram showing an example of the configuration of this type of conventional shaft control device. In FIG. 4, a shaft driving machine control device is connected to the rectifier transformer 1 in anti-parallel with each other and connected to the rectifier transformer 1 to be supplied with power, and a DC motor 2 for driving the shaft driving machine. Two thyristor converters 3 that supply current so as to generate positive and negative torques with respect to the motor, and a field winding 2a of the DC motor 2
And a converter 4 for exciting a field current.

[0006] In such a vertical shaft control device, the secondary voltage of the rectifier transformer 1 is determined so that commutation does not fail during regenerative operation. Because the thyristor converter 3 is a power supply commutation, when the power supply voltage decreases, the thyristor fails to commutate, and an excessive current flows in the DC circuit.

Therefore, in order to lower the probability of such a risk of commutation failure as much as possible, the thyristor phase control angle β during regenerative operation is set so that it does not advance more than 30 degrees in electrical angle, and the thyristor phase control angle during power running operation. A margin is taken in comparison with the control angle α limit (electrical angle of 10 degrees). And, for this margin, it is necessary to make the secondary voltage of the rectifier transformer 1 higher during the regenerative operation than during the power running operation.

However, as shown in FIG. 4, the two sets of thyristor converters 3 must perform both a power running operation and a regenerative operation in accordance with the rotation direction of the DC motor 2, so that the thyristor phase shifts during the power running operation. The control angle α is operated at a point where there is a sufficient margin (for example, 30 degrees in electrical angle). That is, originally, the thyristor phase control angle α during the power running operation may advance to an electrical angle of 10 degrees to operate.

The relationship between the power supply power factor PF and the thyristor phase control angle α is such that the power supply power factor PF is proportional to the cosine (cos α) of the thyristor phase control angle α. That is,
Driving at an electrical angle of 30 degrees is 0.88 times (cos 30 degrees / cos 10
The driving power factor is reduced by about 0.88).

[0010]

As described above, the conventional shaft driving machine control apparatus has a problem that the operating power factor during power running operation is low.

An object of the present invention is to provide an extremely reliable shaft hoist control device capable of significantly increasing the operating power factor during power running operation without increasing the probability of commutation failure during regeneration. To provide.

[0012]

In order to achieve the above object, in an apparatus for controlling the operation of a shaft hoist, first, according to the first aspect of the present invention, on the low pressure side (secondary side),
A rectifier transformer having a powering tap and a regenerative tap having a higher voltage than the powering tap, and a DC motor for driving the shaft driving machine connected to the powering tap of the rectifier transformer and supplied with power. Powering converter, which is energized so as to generate positive-direction torque, and connected in anti-parallel to the powering converter and connected to the regenerative transformer's regenerative tap to receive power and drive the vertical hoist. And a regenerative converter that energizes the DC motor for use so as to generate a negative torque.

According to the third aspect of the present invention, a rectifier transformer having a powering tap and a regenerative tap having a higher voltage than the powering tap on the low voltage side (secondary side); A power running converter that is connected to the power running tap of the vessel and is supplied with power and is energized so as to generate a positive torque to the DC motor for driving the shaft drive, and is connected in anti-parallel to the power running converter. A regenerative converter connected to the regenerative tap of the rectifier transformer and supplied with power, and energizing the DC motor for driving the shaft drive so as to generate a negative torque, and a field of the DC motor. An exciting converter for flowing a field current through the magnetic winding, and a forward / reverse switch provided between the exciting converter and the field winding to switch the polarity of the field of the DC motor by opening and closing operations. And an exciter having .

In particular, a thyristor converter is used as each of the powering converter and the regenerative converter, and the voltage of the powering tap is set to a value obtained from the thyristor phase control angle limit during powering. Is the value obtained from the thyristor phase control angle limit during regeneration.

[0015]

Therefore, in the control device of the vertical hoisting machine of the present invention, the power running converter is connected to the low voltage power running tap on the low voltage side of the rectifier transformer, and the power regeneration converter for regenerating a higher voltage than the power running tap is connected. By connecting the regeneration converter to the tap, the operating power factor during the power running operation can be increased. Further, since the current flowing at the same time is the same and the secondary voltage of the rectifier transformer is lower than the conventional one, the generated reactive power can be reduced.

Furthermore, since the powering converter and the regenerative converter are separated, for example, when the regenerative current is smaller than the powering current, the rating of the regenerative converter is made smaller than that of the powering converter. be able to.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the concept of the present invention will be described. The secondary voltage V _ac of the rectifier transformer is given by the following equation. V _ac = {E _CEMF + (IR _a + IR _e ) × n + e _o } / [1.35 × {(1-x) × cos α− (I _x / 2 + IR _T ) × n}]

Here, E _CEMF : Rotational anti-starting force of DC motor IRa: Armature voltage drop of DC motor IRe: Voltage drop of main circuit wiring e _o : Forward voltage drop of thyristor element x: Power supply voltage fluctuation rate α: thyristor drive angle I _x: rectifier transformer voltage drop (reactance) IRT: rectifier transformer voltage drop (resistance component) n: overload factor

By substituting various constants into the above equation, the secondary voltage V _ACP during the power running operation and the secondary voltage T _ACR during the regenerative operation are calculated, and based on the calculated values, the transformer of the rectifier is calculated. A powering tap and a regenerative tap are provided on the secondary side. In this case, since the limit value of the thyristor phase control angle is different, the voltage during the regenerative operation is naturally higher than the voltage during the power running operation. In this manner, during power running operation, the power running converter connected to the low voltage tap is operated, and the converter is operated at a point as close as possible to the thyristor phase control angle α limit value. In the regenerative operation, the regenerative operation is performed by the regenerative converter connected to the regenerative tap having a higher voltage than the powering tap. Further, if necessary, the rotation direction of the DC motor is switched by switching the polarity of the field of the DC motor. Hereinafter, an embodiment of the present invention based on the above concept will be described in detail with reference to the drawings.

FIG. 1 is a circuit diagram showing a configuration example of a shaft control device according to the present invention. That is, as shown in FIG. 1, the shaft driving machine control device of the present embodiment includes a rectifier transformer 11 having a powering tap 11a and a regenerative tap 11b having a higher voltage than the powering tap 11a.
A powering converter comprising a thyristor converter which is connected to the powering tap 11a of the rectifier transformer 11 and is supplied with electric power, and energizes the DC motor 12 for driving the shaft shaft so as to generate a positive torque. 13 is connected in reverse parallel to the powering converter 13 and is connected to the regenerative tap 11b of the rectifier transformer 11 and is supplied with power. The torque in the negative direction with respect to the DC motor 12 for driving the shaft driving machine. Converter 1 consisting of a thyristor converter energized so as to generate power
4, an excitation converter 15 for flowing a field current to a field winding 12a of the DC motor 12, and an excitation converter 15 provided between the excitation converter 15 and the field winding 12a. It comprises a contactor 16 for forward rotation, which is a switch for forward rotation and reverse rotation for switching the polarity of the field, and an exciter 18 having a contactor 17 for reverse rotation.

Here, the voltage of the powering tap 11a is a value obtained from the thyristor phase control angle (α) limit during powering, and the voltage of the regeneration tap 11b is the thyristor phase control angle (β) during regeneration. The value is obtained from the limit. Next, the operation of the control apparatus for the shaft hoist of the present embodiment configured as described above will be described.

Now, in FIG. 2, skip 3
1 will be described. In this case, in FIG. 3, at the time of the operation in the powering operation region 20, the powering converter 13 supplied from the powering tap 11 a operates to generate a current so that the DC motor 12 generates a forward torque. Flow.

Next, when the skip 31 is gradually wound up and operation starts in the regenerative operation area 21, the powering converter 13 is turned off, and the regenerative converter 14 supplied from the regenerative tap 11b operates. Then, a current is supplied to the DC motor 12 so as to generate a reverse (negative) torque.

Next, when the skip 31 is hoisted in this way, the load is unloaded from the skip 31, the load is loaded on the skip 32, and the skip 32 is hoisted, so that the DC motor 12 must rotate in the reverse direction. For this reason, the forward contactor 1 connected to the output side of the exciter 18
6 is opened, the reverse contactor 17 is closed, and the direction of rotation of the DC motor 12 is changed by changing the polarity of the field of the DC motor 12.

As described above, by switching to the polarity of the field of the DC motor 12, the powering converter 13 always operates during the powering operation regardless of the rotation direction of the DC motor 12.
During regeneration operation, the regeneration converter 14 operates.

As described above, the control apparatus for the shaft hoist according to the present embodiment includes the rectifier transformer 11 having the powering tap 11a and the regenerating tap 11b having a higher voltage than the powering tap 11a. Power converter 13 comprising a thyristor converter, which is connected to the power running tap 11a of the power transformer 11 and is supplied with power, and energizes the DC motor 12 for driving the shaft drive so as to generate a positive torque.
And connected in anti-parallel with the powering converter 13 and connected to the regenerative tap 11b of the rectifier transformer 11 to be fed with electric power, thereby providing a negative torque to the DC motor 12 for driving the shaft shaft. A regenerative converter 14 composed of a thyristor converter energized to generate power, an exciting converter 15 for passing a field current to a field winding 12a of the DC motor 12, and an exciting converter 15 and a field winding 12a, and an exciter 18 having a forward contactor 16 as a forward / reverse switch for switching the polarity of the field of the DC motor 12 by an opening / closing operation and a reverse contactor 17. It was done. Therefore, the following various effects can be obtained.

(A) The driving power factor during power running operation is calculated as V _ACR / V
_Since it can be increased by _ACP times, the driving power factor during power running operation can be significantly increased without increasing the risk of commutation failure during regeneration. (B) The current flowing simultaneously is the same, and the rectifier transformer 11
Is lower than in the prior art, it is possible to reduce the generated reactive power.

(C) Converter 13 for powering and converter 1 for regeneration
For example, when the regenerative current is smaller than the powering current, the rating of the regenerative converter 14 can be smaller than that of the powering converter 13.

In the above-described embodiment, the DC motor 12 is opened and closed by an opening / closing operation between the excitation converter 15 for supplying a field current to the field winding 12a of the DC motor 12 and the field winding 12a.
A forward contactor 16 and a reverse contactor 17 which are forward and reverse switches for switching the polarity of the magnetic field of
Although the case where the exciter 18 is configured has been described, this is not necessarily an essential element of the present invention. That is, as can be seen from the relationship example between the rotation direction and the torque shown in FIG. 3 described above, the operation pattern of the DC motor 12 for driving the shaft driving machine is that the operation in the powering operation region 20 is
This is because, since the region is considerably larger than the operation in the regenerative operation region 21, increasing the driving power factor during the power running operation has a much greater advantage.

[0030]

As described above, according to the present invention, a rectifier transformer having a powering tap and a regeneration tap having a higher voltage than the powering tap on the low voltage side (secondary side), and a rectifier Power converter connected to the powering tap of the power transformer and supplied with power so as to generate a positive torque to the DC motor for driving the shaft drive, and antiparallel to the powering converter A regenerative converter that is connected and connected to the regenerative transformer's regenerative tap and is supplied with power, and energizes the DC motor for driving the shaft drive to generate a negative torque. Accordingly, an exciting converter that supplies a field current to the field winding of the DC motor, and an exciting converter provided between the exciting converter and the field winding to switch the polarity of the field of the DC motor by opening and closing operations Exciter with forward and reverse switch Since so as to constitute a, without increasing the risk of probability of commutation failure at the time of regeneration,
An extremely reliable shaft hoist control device capable of significantly increasing the operating power factor during power running operation can be provided.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing one embodiment of a shaft control device according to the present invention.

FIG. 2 is a diagram showing a configuration example of a shaft hoist.

FIG. 3 is a diagram illustrating an example of a relationship between a rotation direction and a torque of a DC motor for driving a shaft shaft.

FIG. 4 is a circuit diagram showing a configuration example of a conventional shaft control device.

[Explanation of symbols]

11: rectifier transformer, 11a: powering tap, 11b
... Tap for regeneration, 12 ... DC motor, 12a ... Field winding of DC motor 12, 13 ... Converter for power running, 14 ... Converter for regeneration, 15 ... Converter for excitation, 16 ... Contactor for normal rotation, 17 ... Contactor for reverse rotation, 18 ... exciter.

Continuation of the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) H02P 7/00-7/34 B66D 1/46 H02P 5/00-5/26

Claims (4)

(57) [Claims] 1. An apparatus for controlling operation of a shaft hoist, comprising: a rectifier transformer having a powering tap and a regenerative tap having a higher voltage than the powering tap on a low voltage side (secondary side); A powering converter connected to a powering tap of the rectifier transformer, supplied with power, and energized so as to generate a positive torque to the DC motor for driving the shaft drive; and For regenerative power, which is connected in anti-parallel to the regenerative transformer and connected to the regenerative tap of the rectifier transformer to be fed with power and generates a negative torque to the DC motor for driving the shaft hoist. A shaft control device, comprising: a converter; 2. A thyristor converter is used as each of the powering converter and the regenerative converter, and the voltage of the powering tap is a value obtained from a thyristor phase control angle limit during powering. The shaft control device according to claim 1, wherein the voltage is a value obtained from a thyristor phase control angle limit during regeneration. 3. An apparatus for controlling the operation of a shaft hoist, comprising: a rectifier transformer having a powering tap and a regeneration tap having a higher voltage than the powering tap on a low voltage side (secondary side); A powering converter connected to a powering tap of the rectifier transformer, supplied with power, and energized so as to generate a positive torque to the DC motor for driving the shaft drive; and For regenerative power, which is connected in anti-parallel to the regenerative transformer and connected to the regenerative tap of the rectifier transformer to be fed with power and generates a negative torque to the DC motor for driving the shaft hoist. A converter, an excitation converter for flowing a field current to the field winding of the DC motor, and a switching device provided between the excitation converter and the field winding. Forward / reverse to switch polarity of Shaft hoist control device and characterized in that it comprises an excitation device having a use switch, the. 4. A thyristor converter is used as each of the powering converter and the regenerating converter, and the voltage of the powering tap is set to a value obtained from a thyristor phase control angle limit during powering. The shaft control device according to claim 3, wherein the voltage is a value obtained from a thyristor phase control angle limit during regeneration.