JPH03158376A - Control device for hydraulic elevator - Google Patents

Abstract

PURPOSE:To restrain influence by stirring loss which is changed with change in temperature, and thereby efficiently control a hydraulic elevator stably by providing an oil temperature detecting means detecting the temperature of oil within an oil tank, and also providing a control constant regulating means regulating the control constant of an induction motor in response to the detected oil temperature by the aforesaid detection means. CONSTITUTION:The control constant of an induction motor 15 which drives the hydraulic pump of a submerged type power unit submerged in oil within an oil tank at variable speeds through an inverter 14, is suitably regulated in response to the temperature of oil within the oil tank detected by a temperature sensor 18. As a result, this thereby allows the control of the induction motor 15 by a VVVF method to be assumed at all times, which is optimum against load fluctuation due to change in stirring loss accompanied by change in the temperature of oil within the oil tank, and also allows influence by stirring loss which is changed due to change in oil temperature to be restrained so that a hydraulic elevator can thereby be efficiently controlled stably.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a control device for a hydraulic elevator, and particularly to a control device for a hydraulic elevator in which a hydraulic pump and an electric motor are both housed in an oil tank. It is something.

[Prior Art] The power unit of a hydraulic elevator mainly consists of a hydraulic pump, an electric motor for the hydraulic pump, a flow control valve, an oil tank, etc., but in recent years, the above equipment has been housed in the oil tank to save space. A type (hereinafter referred to as a submerged type) that aims to save energy and reduce noise has been proposed. FIG. 2 is a sectional view showing the inside of an oil tank of a conventional submerged type hydraulic elevator.

In the figure, (1) is an oil tank, (2) is an oil tank (1
), (3) is the tank stand installed on the bottom of the oil tank (1).
), (4) is the oil injected into the oil tank (1), (5) is the hydraulic pump immersed in the oil (4), (6) is the hydraulic pump (5) (7) is a mounting bracket that fixes the electric motor (6) to the lid (3); (8) is a hydraulic pump mounted above the lid (3); The flow control valve (9) communicates with the flow control valve (9), which is a pipe connecting the flow control valve (8) and a hydraulic jack (not shown).

The oil tank of a conventional submerged type hydraulic elevator is configured as described above, and when an ascending operation command is issued, the electric motor (6) rotates, which drives the hydraulic pump (5), and the oil ( 4) is sent to a hydraulic jack (not shown) through a flow control valve (8) and piping (9) to move the car (not shown) in the upward direction. On the other hand, when a descending operation command is issued, the flow control valve (8) is opened,
The oil (4) in the hydraulic jack is returned to the oil tank (1), thereby moving the car in the downward direction.

In this way, hydraulic elevators generally raise and lower the car by controlling the flow rate of oil (4) to the hydraulic jack using the flow control valve (8).
As shown in Japanese Patent No. 1-235380, a device has also been proposed that controls the running of a car by controlling the rotational speed of an electric motor (6). In this case, the electric motor (6
) is subjected to variable voltage variable frequency (hereinafter referred to as VVVF) control.

This VVVF system is extremely suitable for a submerged type hydraulic elevator. Because the submerged type stores the above equipment in oil (4),
Compared to conventional power units, the temperature rise inside the oil tank (1) is greater. Therefore, in some cases, it becomes necessary to install a cooling device or the like. However, the VVVF method provides only the necessary flow rate and energy, compared to the conventional method of discarding the oil of a hydraulic elevator and running the car, so the rise in oil temperature is reduced.

[Problems to be Solved by the Invention] In the conventional submerged type hydraulic elevator as described above, the electric motor (6) and the hydraulic pump (5) are immersed in the oil (4). In addition to the load torque for raising and lowering the cage, stirring loss caused by the rotation of the electric motor (6) and hydraulic pump (5) in the oil (4) was added as loss torque. The magnitude of this stirring loss is mainly controlled by the viscosity of the oil (4), and since the viscosity of this oil (4) is a function of temperature, the magnitude of the stirring loss also changes depending on the oil temperature. was.

That is, if the stirring loss is considered as a load applied to the electric motor (6), the magnitude of the load changes depending on the oil temperature.

However, in the conventional VVVF type hydraulic elevator control device, the control constant of the electric motor (6) is kept constant, so it is always optimal for load fluctuations due to changes in stirring loss due to changes in oil temperature. It was not possible to exercise proper control.

Therefore, it is an object of the present invention to provide a control device for a hydraulic elevator using the VVVF method, which can always optimally control the electric motor of a submerged type hydraulic elevator in accordance with changes in oil temperature.

[Means for Solving the Problems] A control device for a hydraulic elevator according to the present invention includes a hydraulic pump (which delivers pressure oil to a hydraulic jack while being immersed in oil (4) in an oil tank (1)). 5), an induction motor (15) that drives the hydraulic pump (5) at variable speed by an inverter (14) while immersed in the oil (4) in the oil tank (1); It is equipped with an oil temperature detection means for detecting the temperature of the oil (4) in the tank (1), and a control constant adjustment means for adjusting the control constant of the induction motor (15) according to the detected oil temperature. be.

[Function] In the hydraulic elevator control device of the present invention, the hydraulic pump (5) of the submerged type power unit immersed in the oil (4) in the oil tank (1) is controlled by the inverter (
14), the control constants of the induction motor (15) which is driven at variable speed are adjusted appropriately according to the detected oil temperature by detecting the temperature of the oil (4) in the oil tank (1). Therefore, the induction motor (15) can always be controlled by the optimum VVVF method in response to load fluctuations due to changes in stirring loss due to changes in oil temperature.

[Example] Fig. 1 is a control block diagram showing a control mechanism by a control device of a hydraulic elevator which is an embodiment of the present invention, and Fig. 2 is a control block diagram showing the inside of an oil tank of a submerged type hydraulic elevator which is an embodiment of the invention. FIG. Note that since FIG. 2 is common to the conventional example, the explanation will be omitted here.

In the figure, (10) is a subtracter that compares the speed command value and the actual speed, (11) is a speed controller that controls the speed according to the value of the subtracter (10), (12) is a current command circuit, and (13) is a
) is a current controller that performs PWM control, (14) is an inverter that drives the motor at variable speed, (15) is an induction motor,
(16) is a current detector that detects the current supplied to the induction motor (15), (17) is an encoder that detects the rotation speed of the induction motor (15), and (18) is the oil tank (1).
A temperature sensor (19) detects the temperature of the oil (4) inside, and a control constant storage circuit (19) stores control constants corresponding to each oil temperature.

The control mechanism of the hydraulic elevator control device of this embodiment is constructed as described above, and operates as follows.

First, the subtracter (10) converts the speed command value ω* and the encoder (
17) and the actual speed ω detected by the speed controller (11), the torque command T* is outputted by the speed controller (11). The current command circuit (12) outputs the current command i* based on the torque command T*, and the current controller (13) outputs the current command i* based on the torque command T*.
) A control signal for the inverter (14) is generated and output from the motor current i detected by the motor current i and the current command i*. Then, the induction motor (15) is driven by the inverter (14), the hydraulic pump (5) is driven, and the hydraulic jack (not shown) is driven, thereby raising and lowering the elevator car (not shown). In this manner, in this embodiment, the entire hydraulic elevator control system is controlled while feeding back the actual speed ω of the induction motor (15) to the speed controller (11) and the current command circuit (12). Also,
In this embodiment, a temperature sensor (18
) is provided, and this temperature sensor (18) detects the temperature of the oil (4) in the oil tank (1), and from this detected value, the control constant storage circuit (19) determines the optimum control constant for speed. Output to the controller (11) and current command circuit (12).

That is, the optimum control of the induction motor (15) can be performed by reading out appropriate control constants for each oil temperature, which have been stored in advance in the ROM of the control constant storage circuit (one), in accordance with the detected oil temperature. It becomes possible. Then, VVVF control of the induction motor (15) is performed using this control constant.

In this way, the hydraulic elevator control device of this embodiment is immersed in the oil (4) in the oil tank (1).
A hydraulic pump (5) that delivers pressure oil to the hydraulic jack, and a hydraulic pump (5) immersed in the oil (4) in the oil tank (1),
an induction motor (15) that drives the hydraulic pump (5) at variable speed using an inverter (14);
) as shown in FIG. and control constant adjustment means for the configuration.

Then, the temperature of the oil (4) in the oil tank (1) is detected,
The control constant of the induction motor (15) is adjusted according to this detected oil temperature, and vVVF control of the induction motor (15) is performed.

Therefore, optimal VVVF control of the induction motor (15) can always be performed with respect to load fluctuations due to changes in stirring loss due to changes in oil temperature. As a result, the influence of stirring loss that changes due to changes in oil temperature can be suppressed as much as possible, making it possible to control the hydraulic elevator in an extremely efficient and stable manner.

[Effects of the Invention] As explained above, the hydraulic elevator control device of the present invention includes a hydraulic pump and an induction motor immersed in oil in an oil tank, and an oil temperature sensor that detects the temperature of the oil in the oil tank. and a control constant adjusting means for adjusting a control constant of the induction motor in accordance with the detected oil temperature, the control constant of the induction motor driving the hydraulic pump at variable speed by an inverter is adjusted to the control constant of the induction motor according to the oil temperature in the oil tank. Since the temperature is detected and adjustments are made appropriately according to the detected oil temperature, the optimum VVVF control of the induction motor can always be performed in response to load fluctuations due to changes in stirring loss due to changes in oil temperature. Therefore, the influence of stirring loss that changes due to changes in oil temperature can be suppressed as much as possible, and extremely efficient and stable control of the hydraulic elevator can be realized.

In the figure, 1: Oil tank 4: Oil 5: Hydraulic pump 6: Electric motor 10: Subtractor 11: Speed controller 12: Current command circuit 13 Two current controller 14: Inverter 1
5: Induction motor 16: Current detector 17: Encoder 18: Temperature sensor 19: Control constant storage circuit.

In the drawings, the same reference numerals and the same symbols indicate the same or equivalent parts.

Claims (1)

[Scope of Claims] A hydraulic pump that sends pressure oil to a hydraulic jack while immersed in oil in an oil tank; and a hydraulic pump that sends pressure oil to a hydraulic jack while immersed in oil in an oil tank; an induction motor that is driven at a variable speed by: an oil temperature detection means that detects the temperature of oil in the oil tank; and a control constant adjustment means that adjusts a control constant of the induction motor according to the detected oil temperature. A hydraulic elevator control device characterized by: