JP2945826B2 - Inverter control hoisting device stop control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stop control method for an inverter-controlled hoist, and more particularly to a stop control method for an inverter-controlled hoist that operates at a high speed with a light load less than a rated load exceeding a rated speed. It is.

[0002]

2. Description of the Related Art In a conventional hoisting apparatus without inverter control, for example, a rated load is M (t) and a rated speed is S
(M / min) first crane and rated load M / 2
In (t), with the second crane having a rated speed of 2S (M / min), the capacity of the hoisting motor is the same, so the deceleration time from full speed to stop is the same, and from the rated speed to stop of both cranes. The deceleration distance of is proportional to each speed only,
The second crane is twice as large as the first crane. However, inverter control is performed to reduce the light load to the rated speed of 2
When performing high-speed operation up to double speed, the time required to stop is determined by the deceleration of the inverter output.If the inverter is at a constant deceleration, stopping from double speed stops compared to stopping from rated speed. The required time is doubled. Therefore, the deceleration distance to stop is quadrupled because it is proportional to both the speed and the time. FIG. 3 shows the relationship between the hoisting control method and the required deceleration time.

[0003]

As described above, since the distance from the start of deceleration to the stop of the hoist varies depending on the hoist, a stop operation is required for an operator who operates both cranes. I feel uncomfortable with the timing,
There were safety issues that led to danger.

SUMMARY OF THE INVENTION In view of the above problems, the present invention is designed to stop a hoisting device of an inverter crane with a distance equivalent to a deceleration distance until stopping in the hoisting device in the conventional control method. An object of the present invention is to provide a stop control method for an inverter control hoisting device.

[0005]

In order to achieve the above object, the present invention provides a method for controlling the stop of an inverter control hoisting apparatus, wherein the inverter control hoisting apparatus operates a light load equal to or less than a rated load at a high speed over a rated speed. In the stop control method of
Set the inverter's deceleration characteristics in two stages. When stopping from a low operating speed range below the rated frequency, decelerate with normal deceleration. On the other hand, when stopping from a high operating speed range above the rated frequency, The deceleration is performed by a large deceleration until the rated frequency is reached, and by a normal deceleration after the rated frequency is reached, so that the deceleration distance until the stop is substantially proportional to the operating speed.

[0006]

The stop control method of the inverter-controlled hoisting apparatus is a method of setting the inverter's deceleration characteristics in two stages in the acceleration / deceleration setting function of the inverter for controlling the hoisting motor, from the high-speed operation speed range above the rated frequency. When stopping, the vehicle is decelerated by a large deceleration until the rated frequency is reached, and by a normal deceleration after the rated frequency is reached, so that the deceleration distance to the stop is substantially proportional to the operating speed.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of a method for controlling the stopping of an inverter control hoist according to the present invention.
FIG. 1 shows the configuration of the inverter control circuit of the hoisting electric motor used to carry out the inverter control hoisting device stop control method.

As shown in FIG. 1, an inverter main circuit 1
Is configured by serially connecting a forward converter 11, a discharge unit 13, and an inverse converter 12 connected to a power switch,
The hoisting motor M is connected to the inverting unit 12 and the control unit 2 is connected to the inverting unit 12. The control unit 2 is configured by connecting a detection unit 24 in series with a base drive unit 23, a PWM generation unit 22, and a sequence controller 21 and in parallel with a PWM generation unit between the base drive unit 23 and the sequence controller 21. The sequence controller 21 is provided with a setting device 4 and an operation controller 3.

When a stop instruction is given by the controller 3 during the hoisting operation, the control unit 2 operates in accordance with the deceleration preset in the sequence controller 21 and stops at a fixed rate while reducing the speed. The change of the deceleration is performed by the setting unit 4. Here, the first and second deceleration set values are inputted as the deceleration, and a predetermined deceleration is set according to the change of the output frequency in the deceleration process until the stop. Shall gain.

The characteristics of the deceleration time until stoppage are as shown in FIG. In order to simplify the description, if the time from the rated speed to the stop at the normal deceleration is 2 seconds, the deceleration time characteristic is 4 seconds from the 200% speed as shown by the broken line in FIG. Becomes In this figure, the deceleration distance until stopping is represented by the area of a triangle.

If the deceleration distances from the 100% speed and the 200% speed are D1 and D2, respectively,

D1 / D2 = ((2 × 1.00) / 2) / ((4 × 2.00) / 2) = 1/4

In the case where the deceleration is constant, it can be seen that the distance required for stopping from twice the rated speed and the rated speed has a difference of four times.

In setting the deceleration of the inverter, when the operation speed is higher than the rated speed, that is, when the inverter output frequency is higher than the rated value (for example, 50 Hz), the deceleration set value of the first stage is taken and the output frequency is set. Is 50Hz
Is detected, and the subsequent steps are set as the second-stage deceleration set value.

Here, as an example, in order to provide deceleration so that the deceleration distance from a speed of 200% is substantially the same as that from a rated speed, a deceleration that reaches 0.8% in 100 seconds to a speed of 100% Decelerate to the point and stop at the normal deceleration after the point A. In this case, the time required to stop is 2.8 seconds, but the deceleration travel distance D3 is as follows.

D1 / D3 = ((2 × 1.00) / 2) / ((0.8 × 1.00) × 3/2 + (2 × 1.00) / 2) = 1 / 2.2

As described above, the deceleration distance from the speed of 100% to the stop is approached, and a sense of strangeness can be prevented.

The deceleration distance D4 from the speed of 150% to the stop is:

D4 = (0.4 × 1.00) × 3/2 + (2.4 × 1.00) / 2) = 1.8

Thus, it can be seen that the sense of distance of the driver is within a range in which safe driving can be obtained.

In such a control method, the determination as to whether the initial speed is a high speed operation speed region or a low speed operation speed region with respect to the rated value, and the detection that the rated speed has been reached from the high speed operation speed region, All are performed by detecting the output frequency of the inverter, and can be easily determined by the sequence controller 21 and the detection unit 24 in the inverter control unit.

In setting such a deceleration, it is naturally necessary to consider the balance with the allowable current value in the discharge unit 13 in FIG.
The actual value should be determined in consideration of the speed range of high-speed operation.

[0023]

According to the stop control method of the inverter control hoisting apparatus of the present invention, the deceleration characteristics of the inverter are set in two stages, and when the inverter is stopped from a low operation speed range below the rated frequency, the normal deceleration is used. When stopping from a high-speed operation speed range higher than the rated frequency, decelerate with a large deceleration until the rated frequency is reached, and decelerate with a normal deceleration after reaching the rated frequency. Since the deceleration distance to the stop is made approximately proportional to the operating speed, the simple control method reduces the operator's sensational discomfort due to the difference in the control method when used together with the conventional control method that does not perform inverter control. Thus, the safety of the hoisting device during operation can be improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an inverter control circuit of a hoisting motor used for carrying out a method of controlling a stop of an inverter control hoisting device of the present invention.

FIG. 2 is a characteristic diagram of a deceleration time until a stop by the stop control method of the inverter control hoisting device of the present invention.

FIG. 3 is a characteristic diagram of a deceleration time until a stop according to a conventional stop control method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inverter main circuit 11 Forward conversion part 12 Inversion part 13 Discharge unit 2 Control part 21 Sequence controller 22 PWM generation part 23 Base drive part 24 Detection part 3 Operation controller 4 Setting device M Hoisting motor

Claims (1)

(57) [Claims] In an inverter control hoisting device for operating a light load equal to or less than a rated load at a high speed exceeding a rated speed, a deceleration characteristic of an inverter is set in two stages, and a low operating speed range below a rated frequency is set. When stopping from the normal deceleration, the motor is decelerated.When stopping from the high-speed operation speed range higher than the rated frequency, the motor is decelerated until the rated frequency is reached. A stop control method for an inverter-controlled hoisting device, wherein deceleration is performed by normal deceleration so that a deceleration distance until stop is substantially proportional to an operation speed.