JPH03152070A - Hydraulic elevator control device - Google Patents

Abstract

PURPOSE:To safety increase the temperature of oil with a cheap arrangement by controlling a hydraulic elevator with the use of a speed signal for a motor during regenerating braking operation of the motor so as to issue a frequency instructing signal by which the regenerative power for the motor becomes zero. CONSTITUTION:When a motor falls in a braking operation, a slip frequency instructing signal 32a becomes negative so that a changeover device 37 is operated, and accordingly, shoes 37a, 37b are turned to contacts (b) respectively. A power control device 39 receives a speed signal 14a, and delivers a frequency instructing signal by which the regenerative power becomes zero, to a control device 36. Meanwhile, a slip frequency instruction signal 32a is inputted to a gain converter 38 from which an output as a voltage instructing signal is delivered to a control device 36. When a slip is controlled so that the sum of the power consumed in the motor and the regenerative power becomes zero, the mechanical energy is all consumed by the motor. Accordingly, the regenerative power are all consumed in the motor so as to be exhibited as a heat within the motor. However, since the motor is stored in oil in a tank, the temperature of the oil is increased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device for controlling a hydraulic elevator by controlling a common motor during ascending and descending.

[Prior Art] In recent years, with the advancement of electronic technology including semiconductors, a method of controlling the rotational speed of an induction motor by changing the applied voltage and frequency (hereinafter referred to as VVVF control) has been applied to hydraulic elevator control devices. It is proposed to apply. This uses a constant discharge pump and variably controls the pump's discharge amount by changing the rotational speed of the electric motor.
It is inexpensive and highly reliable.

By the way, in a hydraulic elevator, when the oil temperature decreases in winter or the like, the viscosity of the oil changes, which may cause a worsening of riding comfort and insufficient motor torque at startup. In the VVVF control mentioned above, since the power loss is small, the oil temperature rise can be controlled using the conventional pump control method (using a variable displacement pump,
Compared to methods such as methods that vary the discharge amount of the pump itself,
Since the oil temperature rises below 172°C, the above-mentioned performance decline in winter is likely to occur.

To improve this problem, a hydraulic elevator control system has been proposed, for example, as disclosed in Japanese Patent Application Laid-Open No. 148877/1983.

FIG. 3 is an overall circuit diagram showing the control device for the hydraulic elevator.

In the figure, (1) is a hoistway, (2) is a hydraulic cylinder installed at the bottom of the hoistway (1) and filled with hydraulic oil (3), and (4) is a hydraulic cylinder installed at the bottom of the hoistway (1) and filled with hydraulic oil (3).
) is a plunger that moves up and down by controlling the amount of oil in the hydraulic cylinder (2), (5) is a cage connected to the head of plunger (4), (7) is a landing, and (8) is a heel to (5). The provided cam (9) is installed in the hoistway (1) and the cam (8
) is engaged with the deceleration command switch, and (lO) is the same stop command switch ((9) and (10) in the figure are for lowering,
A lift is also provided in the same way. ), (11) is a solenoid valve provided between the hydraulic pump (12) and the cylinder (2), (13) is an induction motor that drives the pump (12),
(14) is directly connected to the electric motor (13) and the speed signal (14a
), and (15) is an oil tank connected to the pump (12), which is equipped with an oil temperature detector (16) and a heater (17). (18) is a three-phase AC power supply R
, S, and T to direct current, (19) is a capacitor that smoothes the output of converter (18), and (20) is a converter that controls the pulse width of the smoothed direct current to make it variable voltage/variable. Inverters (21a) to (21c) that generate frequency alternating current power are inserted between the inverter (20) and the electric motor (13), and close when a running command is issued to the car (5), just before landing stops. (22) is the deceleration command switch (9)
The speed command signal (
(23) is a speed control device that inputs the speed command signal (22a) and speed signal (14a) to generate a control signal (23a) for the inverter (20); (24) is an electric motor (13) is a regeneration control device that detects regenerative operation; (25) is an inverter for power regeneration connected in parallel with the converter (18); (26) is a regeneration control device (24) and an oil temperature detector (16) This is an oil temperature control device that controls the heater (17) based on the output of the oil temperature control device.

That is, when a rising command is issued, the contacts (21a) to
(21cl) is closed, and the inverter (
20) is supplied, and the pattern generator (
22) outputs a speed command signal (22a). The control signal (23a) is now output from the speed control device (23), the output of the inverter (20) is controlled, and the electric motor (13) drives the pump (12). Pump (12
), the oil in the tank (15) flows through the solenoid valve (11).
) to the cylinder (2) and the plunger (4)
The car (5) is raised via the .

Next, when a descending command is issued, the solenoid valve (11) is energized and the oil (3) in the cylinder (2) is gradually pumped to the pump (1).
Start sending to 2). At the same time, the electric motor (13) is activated in the opposite direction to the upward direction, causing the pump (12) to reverse. At this time, the amount of oil sent from the cylinder (2) is
), the electric motor (13) is operated under regenerative braking by the pump (12).

At this time, the regenerated power from the electric motor (13) is reversely converted into direct current through the inverter (20), and the capacitor (19) is charged. This regenerated power is then returned to the AC side via the power regeneration inverter (25).

On the other hand, when the voltage of the capacitor (19) becomes higher than a certain value, the regeneration control device (24) outputs an output. The oil temperature control device (26) energizes the heater (17) when the temperature detected by the oil temperature detector (16) is lower than a predetermined temperature and the output from the regeneration control device (24) is input. It works to keep the oil temperature within the appropriate range.

Note that the cam (8) of the car (5) is the deceleration command switch (9).
) and a stop command switch (10) to decelerate and stop, but the details will be omitted.

[Problems to be Solved by the Invention] In the hydraulic elevator control device configured as described above, when the split power is returned to the AC side and the oil temperature is low during regenerative braking, the tank (15 ), the regeneration control device (24), power regeneration inverter (25), oil temperature control device (26), and heater (1
7) etc. are required and are expensive. Furthermore, since the high-temperature heating part of the heater (17) comes into direct contact with the oil in the tank (15), the oil temperature rises locally, causing rapid deterioration of the oil and also affecting safety. There is also a problem.

Although FIG. 3 shows a so-called tri-type in which the pump (12) and electric motor (13) are installed in the air, a submerged type in which both are installed in oil has similar problems.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a control device for a hydraulic elevator that is inexpensive and can safely raise the temperature of oil.

[Means for Solving the Problems] A control device for a hydraulic elevator according to the present invention includes a pump and an electric motor housed in a tank, performs VVVF control on both electric motors during ascending and descending, and uses a speed signal of the motor during regenerative braking. The frequency command signal is controlled to output a frequency command signal that makes the regenerative power of the motor zero.

[Function] In the present invention, in a submerged type hydraulic elevator, a frequency command signal is output such that the regenerated power of the electric motor becomes zero, so that all the regenerated electric power is consumed inside the electric motor.

[Embodiment] Figures 1 and 2 are diagrams showing an embodiment of the present invention. Figure 1 is an overall circuit diagram, and Figure 2 is a block circuit diagram of a speed control device, which is similar to the conventional device. Parts are indicated by the same reference numerals.

In Fig. 1, the hydraulic pump (12), electric motor (13), and speed detector (14) are housed in oil in the oil tank (15), and the regeneration control device (24) and electric power The regeneration inverter (25) is not used.

Figure 2 is shown, for example, in Figure 3 of Japanese Unexamined Patent Publication No. 59-17879, in which (31) is the speed command signal (22
a) and the speed signal (14a), (32) is a compensation element connected to the adder (31) to improve the response of the speed control system, and G (S) is the transmission The function (32a) is the output of the compensation element (32), which is the slip frequency command signal, and (33) is the slip frequency command signal (32a).
) and a speed signal (14a);
(34) is the voltage command signal (3) from the output of the adder (33).
4a); (35) is a frequency command generator that also issues a frequency command signal (35a);
6) is a voltage command signal (34a) and a frequency command signal (35
(37) is in contact when the slip frequency command signal (32a) is positive (including zero); (38) is the contact (b) of the contactor (37a); and (38) is the contact (b) of the contactor (37a). and the control device (36), and outputs a set value according to the input value.
The gain converter (39) is the contact (b) of the contact (37b).
) and control table! (36) is a power control device that emits a frequency command signal such that the regenerated power becomes zero.

Next, the operation of this embodiment will be explained.

When the electric motor (13) is in continuous operation, the speed command signal (22a
) and the speed signal (14a) is positive, so the slip frequency command signal (32a) is also positive, and the switching device (37)
does not operate, and both contacts (37a) and (37b) are in contact with contact point (a). Therefore, the speed command signal (
A slip frequency command signal (32a) corresponding to the deviation between the speed signal (14a) and the speed signal (14a) is output, and this slip frequency command signal (32a) corresponds to a torque command signal. By adding the speed signal (14a) by the adder (33), the voltage command signal (34a) and frequency command signal (35a) are determined so as to satisfy the relationship that the voltage/frequency is approximately constant. It will be done. Based on these command values, the control device (36) controls the switching of the elements of the inverter (20) (or the converter (18) depending on the case when the converter (18) is composed of a thyristor, etc.), and generates the slip frequency command. The electric motor (13) is caused to generate torque corresponding to the signal (32a). Now, the electric motor (13) is started and the car (5) runs, and its speed is automatically controlled with high precision.

On the other hand, when the electric motor (13) enters braking operation, the slip frequency command signal (32a) becomes negative, so the switching device (37)
operates, and both contacts (37a) and (37b) are switched to contact (b). Now the power control device (3
9) inputs the speed signal (14a) and outputs a frequency command signal such that the regenerated power becomes zero to the control device (36). On the other hand, the slip frequency command signal (32a) is input to the gain converter (38), and its output is output to the control device (36) as a voltage command signal.

Here, as shown in the above-mentioned Japanese Unexamined Patent Publication No. 59-17879, if the power consumed inside the electric motor (13) is Pl, and the power generated as regenerative power is Pg, then P1+Pg=O・If the slip S is controlled so that...■, then all the mechanical energy will be consumed inside the electric motor (13).

Here, the slip S is 9 22, r' l +1 -order resistance r2 of the motor (13)
= Secondary resistance (-order conversion value) of the electric motor (13) go; Excitation conductance Z: Total impedance of the electric motor (13). However, by setting Z = Z (S) and satisfying the equation 0 regardless of the input voltage, the slip S that generates braking force without power transfer can be found.

All of the regenerated power will now be consumed within the electric motor (13).

This regenerated power appears as heat generated by the electric motor (13), but since the electric motor (13) is housed in oil in the tank (15), the heat generated by the electric motor (13) does not increase the temperature of the oil. become.

Furthermore, the rotation of the electric motor (13) causes the oil to be pumped into the tank (15).
), it does not cause a local temperature rise of the oil.

The output of the contact point (b) of the contactor (37a) in Fig. 1 is further input to the power control device (39), and the applied voltage and speed are used as inputs to control the slippage without transfer of active power to the power control device (39). The calculation may be performed by the control device (39).

In addition, if a drop in oil temperature becomes a problem when the elevator is stopped for a long time, the oil temperature can be detected and when the temperature drops below a predetermined temperature, the elevator can be forcibly operated using regenerative power. It is also possible to increase the temperature.

[Effects of the Invention] As explained above, in this invention, a submerged type hydraulic elevator outputs a frequency command signal that makes the regenerated power of the motor zero, so all the regenerated power is consumed inside the motor. The generated heat raises the oil temperature, which has the effect of safely increasing the oil temperature without the need for special equipment, with an inexpensive configuration.

[Brief explanation of the drawing]

FIG. 1 is an overall circuit diagram showing an embodiment of a hydraulic elevator control system according to the present invention, FIG. 2 is a block circuit diagram of the speed control system shown in FIG. 1, and FIG. 3 is a conventional hydraulic elevator control system. FIG. 1 is an overall circuit diagram showing the device. In the figure, (2) is a hydraulic cylinder, (5) is a cage, and (12)
is a hydraulic pump, (13) is an induction motor, (14a) is a speed signal, (15) is an oil tank, (18) is a converter, (20) is an inverter, (22a) is a speed command signal,
(23) is a speed control device, (34a) is a voltage command signal,
(35a) is a frequency command signal, (36) is an inverter control device, and (39) is a power control means (power control device). Note that the same reference numerals in the figures indicate the same or corresponding parts. Figure 2

Claims (1)

[Claims] In an elevator in which a hydraulic pump and an electric motor for driving the hydraulic pump are housed in an oil tank, the electric motor is controlled by a voltage command signal and a frequency command signal during ascending and descending, and the hydraulic pump is driven to drive the car, A control device for a hydraulic elevator, comprising power control means for outputting the frequency command signal that is controlled by a speed signal of the electric motor so that regenerative power of the electric motor becomes zero during regenerative braking of the electric motor.