JPH03216476A - Control device for elevator - Google Patents

Abstract

PURPOSE:To obtain simple constitution by providing a safety circuit for detecting a trouble in a main circuit between a converter and an inverter and further providing an arithmetic device for fetching an output or the like from this safety circuit so as to apply a DC brake before action of an electromagnetic brake or to stop a PWM output. CONSTITUTION:When a safety circuit, except a safety circuit 21 of an inverter 4, is actuated during floor arrival action by running an elevator, a converter 2 is disconnected from power supplies R, S, T by deenergizing an electromagnetic switch 1. Now the microprocessor of a speed controller 15 keeps a DC current to continue its flow in an induction motor 5 until an electromagnetic brake 14 is actuated. Accordingly, DC braking acts on the motor 5 during this time to control acceleration of a cage 12. In the case such that the safety circuit 21 is actuated during the floor arrival action by running the elevator, the inverter 4 can not be continuously operated with the inverter 4 in trouble. That is, a PWM signal is stopped when an output of the circuit 21 is deenergized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an elevator control device, and particularly to an improvement in a safety device that operates when an abnormality occurs while the elevator is running.

[Prior Art] FIG. 6 is a configuration diagram showing an example of a conventional elevator control device disclosed in, for example, Japanese Utility Model Application Publication No. 152693/1983. In the figure, R, S, and T are three-phase AC power supplies, (
la). (lb). (lc) is the contact of the first electromagnetic switch, (2) is the converter, (3) is the smoothing capacitor, (4) is the inverter, (5) is the induction motor that drives the elevator sheave, and (6) is Three-phase full-wave bridge for charging,
(9a). (9b) is a contact point of the second electromagnetic switch.

In the control device configured as described above, while the elevator is operating, the first electromagnetic switch is excited and the contacts (la),
(lb). (le) is closed, AC power supplies R, S, T
is converted into DC by the converter (2), further smoothed by the smoothing capacitor (3), and then sent to the inverter (4).
) is converted into variable voltage, variable frequency alternating current, which is then fed to the induction motor (5).

If an abnormality occurs while the elevator is running, the first electromagnetic switch is deenergized and contacts (la). (lb) , (l
c) is released, and the contacts (9a) of the second electromagnetic switch are opened.
(9b) is closed and the AC power source is converted to DC voltage by the charging three-phase full-wave bridge (6), which is then supplied to the two phases of the induction motor (5) to apply DC braking. .

[Problem to be Solved by the Invention] In the elevator control device as described above, when the elevator reaches the floor and the safety circuit is activated while the door is open to initiate an emergency stop, the inverter (4) immediately stops. Electromagnetic brake is activated. However, with this electromagnetic brake, there is a time delay between when the first electromagnetic switch is deenergized and when braking torque is generated, and during this time delay, the car increases due to unbalanced torque between the car and the counterweight. When the car speeds up and the gap between the car floor and the landing floor (hereinafter referred to as bedsores) increases, it poses a danger to passengers. As a countermeasure to this, it is necessary to apply DC braking to the induction motor (5), which requires the installation of a three-phase aftereffect bridge (6) for charging, an electromagnetic switch for switching the main circuit, etc., which makes the device expensive. There was a problem.

This invention was made to solve the above-mentioned problems, and it is possible to apply DC braking with a relatively simple configuration without the need for a special three-phase full-wave bridge for charging or equipment for switching the main circuit. The purpose of the present invention is to obtain an elevator control device that can perform the following steps.

[Means for Solving the Problems] An elevator control device according to the present invention includes a converter that exchanges an AC power source with a direct current, and a hoisting induction motor that converts the output of this converter into an alternating current of variable voltage and variable frequency. A safety circuit is installed to detect a failure in the main circuit between the inverter that supplies power to the inverter, and the output from this safety circuit is also taken in to apply DC braking or stop PWM output before operating the electromagnetic brake. It is equipped with a computing unit.

[Operation] If a safety device other than the safety circuit that detects a failure in the main circuit between the converter and inverter operates while the door of the co-elevator is open, the inverter is operated for a specified period of time through the specified procedure and the hoisting induction motor is DC braking is applied to the motor, and the PWM output is stopped when the safety circuit is activated (failure of the above-mentioned main circuit) or when other safety devices are not activated.

[Embodiment] FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a block diagram of the speed control device in FIG. 1.

In FIG. 1, portions (1) to (5) are the same as or equivalent to the portions with the same symbols in FIG. 6, which shows a conventional example.

(10) is a sheave driven by an induction motor (5),
The car (12) connected to the index lobe (11) and the counterweight (13) are raised and lowered. (14) is an electromagnetic brake provided in contact with the shaft of the sheave (lO), (15) is a speed control device, and a speed detector (1) is attached to the induction motor (5).
6) and the output of the speed command device (17), and provides a PWM signal to the inverter (4). (l8) is a current detector that detects the current flowing between the inverter (4) and the induction motor (5), and its output is the speed controller (l5).
) will be returned. (l9) and (20) are converters (
A current detector (21) detects the current flowing between the inverter (4) and the inverter (2);
This is a safety circuit that operates when the output of (20) exceeds a predetermined value.

In FIG. 2, (16a) is the output of the speed detector (16), (17a) is the output of the speed command device (17), and the interface (23). (22) to the microprocessor (27), R O M (
28) and RAM (29) perform a comparison operation and output to the PWM converter (30). (1e) is the contact output of the electromagnetic switch (1), (2lb) is the safety circuit (21)
(33a) is the door open signal, (18a) is the output of the current detector (18), and the interface (24) is the output of the current detector (18).
), (25), (H) and A/D converter (3l
) into the microprocessor (27). (15a) is the output of the speed control device (15).

Figure 3 is an explanatory diagram showing the connection between the electromagnetic switch (1) and each contact, where (1a) is the excitation coil of the electromagnetic switch (1), <2
1a) is a contact of the safety circuit (21), (32a) is a contact of a start command circuit, and (34a) is a contact of a safety circuit other than the safety circuit (2l).

Next, the operation of the elevator control system configured as described above will be explained using the flowchart shown in FIG. First, in step 41, it is determined whether or not the electromagnetic switch (1) is excited, and if YES, the process proceeds to step 47, in which the PWM output is set to follow the output (15a) of the speed control device (15). Control. If No, proceed to step 42, where it is determined whether the safety circuit (2l) of the inverter (4) is operating, and if YES, step 48
Proceed to and stop PWM output. On the other hand, if No, the process proceeds to step 43, where it is determined whether or not a safety circuit other than the safety circuit (21) is operating, and if No, step 4
The process proceeds to step 8 to stop the PWM output, and if YES, the process proceeds to step 44.

Next, in step 44, it is determined whether the door is closed, and if YES, the process proceeds to step 48 to stop the PWM output, and if NO, the process proceeds to step 45, where the electromagnetic switch (1) is excited. It is determined whether a predetermined amount of time or more has elapsed since the coil (la) was deenergized. And Y
If ES, the process proceeds to step 48 to stop the PWM output, and if NO, the process proceeds to step 46, where the PWM output is controlled so that a predetermined DC current flows.

As described above, when the elevator is running and a safety circuit other than the safety circuit (21) of the inverter operates during the landing operation, the electromagnetic switch (1) is deenergized and the converter (2) , is cut off from T. At this time, the microprocessor (27) calculates the electromagnetic switch (
Since 1) is deactivated, proceed to the calculation in step 42,
By the calculations after step 43, the electromagnetic brake (14
) continues to flow through the induction motor (5) until it operates. Therefore, during this time, DC braking is applied to the induction motor (5) to prevent the car (12) from increasing speed. Also,
The time delay of the electromagnetic brake (14) is short, about 0.5 seconds or less, so even if the electromagnetic switch (1) is open, the electric charge stored in the electrolytic capacitor (3) will not be able to supply current during this time. I do.

Also, if the elevator is running and the safety circuit (21) of the inverter is activated during the landing operation, in this case, the inverter (4) is malfunctioning and the inverter (4) will continue to operate. I can't drive. That is, proceeding from step 4l to step 42, the safety circuit (21)
If the output of PW is de-energized, proceed to step 48 and
The M signal is stopped, and the operation of the inverter (4) is stopped.

Figure 5(a) is a diagram showing the relationship between car speed and stopping distance, and Figure 5(b) is a safety circuit (21) as shown in Figure 5(c).
FIG. 3 is a diagram showing the relationship between the car speed and the stopping distance when DC braking is applied by the output of the car. As is clear from both figures (a) and (b), when DC braking is applied by the safety circuit (21) according to the present invention shown in figure (b), the conventional safety circuit as shown in figure (a) is activated. Since there is no speed increase of the car between the time the car stops and the time when the electromagnetic brake operates, the distance traveled by the car until the car comes to a halt is shortened, so bedsores when landing on the floor can be reduced.

[Effects of the Invention] As described above, according to the present invention, a safety circuit is provided that detects an abnormality in the inverter by detecting the current value between the converter and the inverter, and when an abnormality occurs while the elevator is running, Depending on the operating status of the safety circuit, DC braking is applied before braking by the electromagnetic brake, or P is applied instantaneously.
Since the configuration is configured to stop the WM output, there is no need to separately install an electromagnetic switch for switching the main circuit, a three-phase aftereffect bridge for charging, etc., and it is possible to use an inexpensive elevator control device with a DC braking function. Obtainable.

[Brief explanation of drawings]

Fig. 1 is a block diagram of an embodiment of the present invention, Fig. 2 is a block diagram of the speed control device in Fig. 1, and Fig. 3 is an explanatory diagram showing the connection between the electromagnetic switch and each contact in Fig. 1. , FIG. 4 is a flowchart for explaining the operation of this invention, and FIG.
The figure is a diagram showing the relationship between the car stopping distance during braking by a conventional control device and the braking by the present invention, and FIG. 6 is a configuration diagram showing an example of a conventional elevator control device. In the figure, (2) is a converter, (4) is an inverter, (5) is an induction motor, (14) is an electromagnetic brake, and (l
5) is a speed control device, (21) is a safety circuit, and (27) is a microprocessor. Note that the same symbols in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] An elevator control device comprising a converter for converting AC power into DC power, and an inverter for converting the output of the converter into a variable voltage, variable frequency AC power to supply power to a hoisting induction motor. A safety circuit that detects a failure in the main circuit between the two, and a calculation function that takes in the output from this safety circuit and applies DC braking or stops PWM output after applying a predetermined procedure before braking with the electromagnetic brake. 1. A control device for an elevator, comprising a speed control means having a speed control means.