JPH04350069A - Controller for hydraulic elevator - Google Patents

Abstract

PURPOSE:To improve the starting characteristics and ride comfortableness characteristics during run by detecting a rotation speed of a hydraulic pump, inputting it to a speed determining means, selecting a control constant for a controller for a high-precision high-speed response for a low speed range, and controlling for a low-speed response for a high speed range. CONSTITUTION:A rotation speed of a three-phase induction motor 6 is detected by a speed detector 18, it is given to an adder 15, and it is given to a speed determining means 20 simultaneously. For a speed-zero range with a very low rotation speed, a signal A is generated, and a control constant A for characteristics of a high-precision high-speed response for a controller 14 is selected by a controller selector 21, so a smooth inverse rotation is obtained. The speed determining means 20 generates a signal B for a speed exceeding the very low speed-zero range, a control constant B for the controller 14 is selected by the controller selector 21. The performance for the precision and response speed becomes a little low, which is convenient for a vibration system of an elevator comprising a hydraulic system and a rope system, thereby the vibration of a basket during run is reduced.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control system for an inverter-controlled hydraulic elevator, and more particularly to a control system for an inverter-controlled hydraulic elevator with improved starting characteristics.

0002

[Prior Art] Conventionally, in an inverter-controlled hydraulic elevator, when starting the elevator in a descending operation, for example, as disclosed in Japanese Patent Laid-Open No. 61-13288, a hydraulic pump is operated by an electric motor, and the hydraulic pump is first operated in an ascending operation. After rotating in the direction of rotation to suck oil from the oil tank and making the hydraulic pressure on the hydraulic pump side the same as the hydraulic pressure on the cylinder side, open the electromagnetic switching valve, reverse the rotation direction of the hydraulic pump, and transfer the oil from the hydraulic cylinder to the oil tank. The car was being driven downward by pumping oil and lowering the hydraulic plunger.

0003

[Problems to be Solved by the Invention] In the prior art, when starting a car to descend, the hydraulic pump is rotated in the upward direction to make the hydraulic pressure on the plunger side and the hydraulic pressure on the hydraulic pump side approximately equal. to open the hydraulic valve, and then rotate the hydraulic pump in the downward operating direction in accordance with the speed command.

There is a phenomenon in which the hydraulic pump does not pass smoothly due to friction in a region where the rotational direction of the hydraulic pump changes from an upward direction to a downward direction and passes through a zero rotational speed.

[0005] Therefore, there is a problem in that a shock occurs when starting the car.

[0006] An object of the present invention is to improve the starting characteristics of an inverter-controlled hydraulic elevator with smooth and favorable ride comfort characteristics.

[0007]

[Means for Solving the Problems] In order to achieve the object of the present invention, the rotational speed of the hydraulic pump 5 or the three-phase induction motor is detected by a speed detector, and the detected speed is input into a speed determiner. Then, in a low speed region, the speed determiner selects the control constant of the controller so as to provide high precision and fast response, so as not to be affected by friction. In addition, in a high speed region, the control constant of the controller is set to a slower response than in a low speed region, so that control is performed so as not to be influenced by the rope vibration system.

In this way, the control constant of the controller is made variable depending on the rotational speed of the three-phase induction motor or the hydraulic pump.

[0009]

[Operation] To achieve the purpose, the speed detector detects the speed of the three-phase induction motor and hydraulic pump. The speed determiner has characteristics similar to the friction characteristics of a three-phase induction motor and a hydraulic pump, and outputs a signal A in a low speed region where the friction between the three-phase induction motor and hydraulic pump is large, and outputs a signal B in other regions. It has the characteristic of obtaining an output.

[0010] The output signal of the speed determiner operates the controller selector. When the controller selector receives signal A, it selects a control constant A that has high precision and fast response characteristics.

[0011] When the control constant A of the controller is reached, it has high precision and high-speed response, so disturbance caused by friction of the three-phase induction motor and hydraulic pump can be sufficiently controlled, and the rotation direction of the three-phase induction motor and the hydraulic pump can be changed. It can be controlled smoothly and sufficiently even in the zero speed region, and the startup characteristics are smooth with little shock.

Further, when the controller selector receives the signal B, the controller characteristic selects the control constant B.

The control constant B of the controller has somewhat lower accuracy and response speed performance than the control constant A. This is advantageous for the vibration system of the elevator, which consists of a hydraulic system and a rope system, and serves to reduce vibrations of the car during travel.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a hydraulic elevator control system according to the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a system diagram showing the configuration of an embodiment of the present invention, and FIG. 2 is a time chart explaining the operation of the present invention.

In FIG. 1, 1 is a car, 2 is a hydraulic cylinder, 3 is a plunger, 4 is a rope, 5 is a hydraulic pump,
6 is a three-phase induction motor, 7 is an oil tank, 8 is a solenoid switching valve,
9 is an inverter device, 10 is a hydraulic pressure detector, 11 is a hydraulic signal converter, 13 is a limiter, 14 and 14' are inverter controllers, 15 is an adder for speed command and actual speed, 16 is a speed command device, 17a ~17d is an oil pipe, 18 is a speed detector, 2
0 is a speed determiner, and 21 is a controller selector.

Each operation will be explained with reference to a time chart during descending operation shown in FIG.

Now, at time T1, the electromagnetic switching valve 8 is closed, so the car 1 is kept stopped. At this time, the plunger side hydraulic pressure is a hydraulic pressure Pj corresponding to the load of the car 1,
The oil pressure detector 10 indicates the plunger side oil pressure in FIG.

The plunger side oil pressure detected by the oil pressure detector 10 passes through an oil pressure signal converter 11 and a limiter 13, and is applied to a speed command and actual speed adder 15 as a plunger side oil pressure command, that is, a pump rotation command.

The three-phase induction motor 6 and the hydraulic pump 5 rotate in the upward operation direction at a pump rotational speed d, and the pump side oil pressure e becomes the oil pressure Pp, which is approximately the same as the plunger side oil pressure Pj. At the same time as opening the electromagnetic switching valve 8 at time T2,
A speed command C for descending operation is given to the adder 15 by the speed command device 16 .

The rotational speeds d of the three-phase induction motor 6 and the hydraulic pump 5 rotate in reverse from the ascending direction to the descending direction. When this rotation direction changes, the rotation speed is very low (zero speed)
In this region, as shown in FIG. 3, the frictional force is very large. Smooth reverse rotation cannot be obtained.

The rotational speed of the three-phase induction motor 6 is detected by a speed detector 18 and fed to an adder 15 at the same time as a speed determiner 20, which generates a signal A when the rotational speed is in a very low zero speed region. and gives it to the controller selector 21.

When the controller selector 21 receives the signal A, the controller selector 21 selects a control constant A that has characteristics of the controller 14 with high precision and high speed response.

When the controller 14 has a control constant A, high precision
Due to its high-speed response, smooth reverse rotation can be obtained. For example, characteristic A has a high gain characteristic, as shown in the frequency-gain characteristic shown in FIG.

In other words, when the rotation direction changes, in the very low zero speed region W, smooth reverse rotation can be obtained even if the frictional force is very large as shown in FIG. Speed d and car speed f start smoothly,
To accelerate. Therefore, fluctuations in the pump side oil pressure e are small, and the car acceleration g is smooth, resulting in good starting characteristics. The speed determiner 20 generates a signal B when the speed exceeds a very low zero speed region W, and the controller selector 21 selects the control constant B of the controller 14.

As shown in FIG. 4, the control constant B of the controller 14 has somewhat lower performance in accuracy (control gain) and response speed than the control constant A. By doing so, it is convenient for the vibration system of the elevator consisting of the hydraulic system and the rope system, and the vibration of the car during traveling is reduced.

According to the present invention, it is possible to control the electric motor and the hydraulic pump during startup without being affected by the friction peculiar to the low speed region, thereby improving the startup characteristics and providing a hydraulic elevator with excellent riding comfort.

FIG. 5 shows another embodiment. 5, the difference from FIG. 1 is that the car 1 is equipped with an auxiliary rope, one end of which is equipped with a speed detector 19, and a speed signal of the car 1 is provided to the speed determiner 20. .

The control constant A of the controller 14 is applied in the zero speed region where the speed of the car 1 is very low, and the control constant B is applied in the high speed region.

In other words, the configuration is such that the control constants are changed when the car is stopped and when the car is running.

According to this embodiment, it is possible to provide a hydraulic elevator with good starting characteristics of the car and good riding comfort characteristics during running.

[0032]

[Effects of the Invention] According to the present invention, it is possible to perform high-precision, high-speed response control that is unaffected by the frictional force of the electric motor and hydraulic pump. It is possible to provide a hydraulic elevator with smooth operating characteristics unaffected by the vibration systems of the hydraulic system and rope system, and with good ride comfort.

[Brief explanation of drawings]

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

FIG. 2 is a timing chart of the present invention.

[Fig. 3] Characteristic diagram of the frictional force of the electric motor and hydraulic pump.

FIG. 4 is a gain-frequency characteristic diagram showing the performance of the control system of the present invention.

FIG. 5 is a system diagram of another invention.

[Explanation of symbols]

1... Car, 5... Hydraulic pump, 6... Electric motor, 9... Inverter device, 14... Controller, 18, 19... Speed detector, 2
0...Speed determiner, 21...Controller selector.

Claims (2)

[Claims] 1. An oil pipe for supplying oil to a hydraulic cylinder, the hydraulic pump, an oil tank for supplying oil to the hydraulic pump, an electromagnetic switching valve for opening and closing a hydraulic circuit between the hydraulic cylinder and the hydraulic pump, and the hydraulic pressure. an electric motor that drives the pump; a plunger that moves up and down by sending oil to the hydraulic cylinder;
a car that is controlled by the vertical movement of the plunger; a power converter that supplies power to the electric motor; a speed detector that detects the rotational speed of the electric motor; An inverter-controlled hydraulic elevator comprising a controller that controls a converter, wherein a control constant of the controller is changed in a speed range of the electric motor. 2. An oil pipe for supplying oil to a hydraulic cylinder, the hydraulic pump, an oil tank for supplying oil to the hydraulic pump, an electromagnetic switching valve for opening and closing a hydraulic circuit between the hydraulic cylinder and the hydraulic pump, and the hydraulic pressure. an electric motor that drives the pump; a plunger that moves up and down by sending oil to the hydraulic cylinder;
A car controlled by the vertical movement of the plunger, a speed detector that detects the speed of the car, a power converter that supplies power to the electric motor, a speed detector that detects the rotational speed of the electric motor, and the speed detector. In an inverter-controlled hydraulic elevator comprising a controller that operates according to the output of the car and a speed command and controls the power converter, the car speed determiner is actuated by the signal from the car speed detector to determine the car speed. A hydraulic system characterized by generating a signal A and selecting a controller with a control constant A by a controller selector in a zero speed region where the speed is low, and selecting a controller with a control constant B at speeds exceeding the zero speed region. Elevator control device.