JPH0570047A - Control device for ac elevator - Google Patents

Abstract

PURPOSE:To safely rescue passengers in an emergency such as a power stoppage by providing a control circuit operating an electromagnetic brake and stopping a cage at the landing position if the output of a current detector exceeds a preset value while the cage travels at the constant speed and the cage reaches a point at the preset distance from the landing position when a motor is driven by an emergency DC power source. CONSTITUTION:A current detector 13 detecting the input current of a motor 5 driving the cage 12 of an AC elevator and an emergency DC power source driving the motor 5 in an emergency are provided, when the motor 5 is driven by the emergency DC power source, the input current of the motor 5 driving the cage 12 is detected by the current detector 13, and the motor 5 is driven by the emergency DC power source in an emergency. When the motor 5 is driven by the emergency DC power source, if the output of the current detector 13 exceeds a preset value while the cage 12 travels at the constant speed and the cage 12 reaches a point at the preset distance from the landing position in a hoistway, an electromagnetic brake 9 is operated, and the cage 12 is stopped at the landing position by a control circuit 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an AC elevator, and more particularly to a control device for an AC elevator that can be safely rescued in an emergency.

[0002]

2. Description of the Related Art A conventional example will be described. FIG. 3 is a block diagram showing a conventional AC elevator control device disclosed in, for example, Japanese Patent Publication No. 63-27270. In the figure, three-phase AC power source 1 for generating an AC output, 2 diodes D ₁ to D ₆
And consists transistors Q ₁ to Q _6, 3-phase full-wave bridge circuit for converting an AC output of the three-phase AC power supply 1 into DC, the capacitor for smoothing the output of the three-phase full-wave Burijijji circuit 2 3, 4, transistor Q _{7 to} Q ₁₂ and diode D _{7 to} D
_The inverter 5 is provided with the DC output of the three-phase full-wave bridge circuit 2 via the capacitor 3, the output of the inverter 4 is supplied to the inverter 5, the induction motor for driving the elevator car (not shown), and 6 is one end. A contact connected to the positive power supply terminal side of the three-phase full-wave bridge circuit 2 and the inverter 4,
7 is a battery whose positive terminal is connected to the three-phase full-wave bridge circuit 2 and the negative power source terminal side of the inverter 4, and the other terminal is connected to the other end of the contact 6, and 8 is a net wheel installed in the induction motor 5. , 9 is an electromagnetic brake of the net wheel 8, 10 is a counterweight, 11 is an index rope which is connected to the counterweight 10 at one end and is wound around the net wheel 8, and 12 is connected to the other end of the index rope 11. It is a basket. The contact 6 and the battery 7
Constitutes an emergency DC power supply.

Next, the operation of the conventional example will be described with reference to FIG. Normally, the DC output from the three-phase full-wave bridge circuit 2 is smoothed by the capacitor 3 and converted into a three-phase voltage by the inverter 4. Induction motor 5 during power running in normal operation
The frequency of the inverter 4 is gradually increased and the power running torque of the induction motor 5 is controlled while the ratio of the terminal voltage to the frequency is constant.

[0004] During normal operation the braking, the induction ratio between the terminal voltage and frequency of the motor 5 is reduced gradually has been while the frequency of the inverter 4 constant, the transistor Q ₁ to Q ₆ of the three-phase full-wave bridge circuit 2 The conduction control is performed according to the phase of the three-phase AC power supply 1, the regenerative power of the induction motor 5 is returned to the three-phase AC power supply 1, and the regenerative braking torque of the induction motor 5 is controlled. In this way, the power running torque and the regenerative braking torque of the induction motor 5 are appropriately controlled, and the acceleration control of the elevator during normal operation is performed.

In an emergency such as a power failure, the contact 6 is closed and the battery 7 is connected to the DC power supply terminal of the inverter 4 to perform rescue operation. That is, in the event of an emergency such as a power failure, the DC output of the battery 7 is supplied, a current as shown in FIG. 4 (a) flows through the induction motor 5, and the elevator operates in the direction of being pulled by the load. The basket 12 runs at a constant speed C as shown in FIG. While the car 12 is traveling at a constant speed C, a large deceleration current I _M flows to stop the car 12 at the nearest floor landing position, as shown in FIG. 4 (a), and as shown in FIG. 4 (b). As shown, the car 12 slows down. In addition, the terminal voltage V of the induction motor 5 during deceleration of the rescue operation
_M is expressed by equation (1).

V _M ≈I _M [R _s + R _r (ω / ω _s )] (1)

However, in the equation (1), R _s is the resistance value of the stator of the induction motor 5, R _r is the resistance value of the rotor of the induction motor 5, ω is the output frequency of the inverter 4, and ω _s is the slip of the inverter 4. Indicates the frequency. Further, the terminal voltage V _M of the induction motor 5 can be calculated by ignoring the voltage drop in the transistors Q _{7 to} Q ₁₂ and the diodes D _{7 to} D ₁₂ of the inverter 4.
Since it does not become higher than the terminal voltage V _D of the battery 7, the formula (2) holds.

2 ^1/2 V _M ≤V _D / 2 (2)

Therefore, from the expressions (1) and (2), the deceleration current I _M flowing through the induction motor 5 is limited as shown in the expression (3).

I _M ≦ V _D / [2 · 2 ^1/2 (R _s + R _r (ω / ω _s ))] ... (3)

[0011]

The conventional AC elevator control device is constructed as described above, and the deceleration current I limited by the formula (3) to the induction motor 5 during deceleration during the rescue operation.
Only _M flows. However, when the load in the car 12 is heavy (heavy load), the deceleration current required for the car 12 to stop at the landing position is larger than the deceleration current I _M limited by the formula (3), so If you try to decelerate with the position as the target,
There was a problem that 12 could not slow down sufficiently and went too far to the landing position.

The present invention has been made in order to solve such a problem. In an emergency such as a power failure, the car is stopped at the landing position even if the load in the car is heavy, and the passengers are safely rescued. It is an object of the present invention to obtain a control device for an AC elevator that can do the work.

[0013]

An AC elevator control apparatus according to the present invention is a current detector for detecting an input current of an electric motor for driving a basket of an AC elevator, and an emergency DC for driving the electric motor in an emergency. When the electric motor is driven by the power supply and the emergency DC power supply, the output of the current detector when the car is traveling at a constant speed exceeds a predetermined value, and the car is predetermined from the landing position in the hoistway. When a position point at a distance is reached, an electromagnetic brake is operated to stop the car at the landing position.

[0014]

In the present invention, the current detector detects the input current of the electric motor for driving the basket of the AC elevator, and the emergency DC power supply drives the electric motor in an emergency. When the electric motor is driven by the emergency DC power supply, the output of the current detector exceeds a predetermined value while the car is traveling at a constant speed by the control circuit, and the car is in the landing position in the hoistway. When a position point located at a predetermined distance from is reached, the electromagnetic brake is activated and the basket stops at the landing position.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention. In the figure, 1 to 12 are the same as those shown in FIG. 4, 13 is a current detector connected between the inverter 4 and the induction motor 5 to detect the input current of the induction motor 5, and 14 is a current detector. A speed detector, which is provided between the induction motor 5 and the sheave 8, detects the rotational speed of the induction motor 5, and 15 is a three-phase full-wave bridge circuit 2, an inverter 4, an electromagnetic brake 9, and a current detector 13. The control circuit is connected to the speed detector 14 and includes a microcomputer.

The emergency operation of FIG. 1 will be described below with reference to the flowchart of FIG. In the hoistway of the basket 12,
Corresponding to each floor, a position point for detecting a relevel zone and a door zone is usually provided at a predetermined distance from the landing position in addition to the landing position. In an emergency, the position 12 is used to stop the car 12.

That is, in step S1, the control circuit 15
Judges whether the input current of the induction motor 5 detected by the current detector 13 is less than or equal to a predetermined value while the car 12 is traveling at a constant speed from the output of the speed detector 14, and determines that the input current is less than or equal to the predetermined value. If (YES), the process proceeds to step S2. In step S2, the control circuit 15 controls the three-phase full-wave bridge circuit 2 until the car 12 reaches the nearest floor landing position.
And the inverter 12 is controlled to decelerate the car 12. Then, in step S3, the control circuit 15 determines whether or not the basket 12 has reached the landing position, and when it determines that it has arrived.
If (YES), the process proceeds to step S4. In step S4, the control circuit 15 operates the electromagnetic brake 9 to control the sheave 8 and stop the basket 12.

Further, in step S1, the control circuit 15
When it is determined that the input current of the induction motor 5 detected by the current detector 13 exceeds a predetermined value (in the case of NO),
That is, when the load is heavy, the process proceeds to step S5. In step S5, the control circuit 15 determines whether or not the car 12 has reached the position point. When it is determined that the car 12 has reached the position point (in the case of YES), the process proceeds to step S4 and, as described above, the car 12
To stop.

In step S3, the control circuit 15
Is determined that the basket 12 has not reached the landing position.
If (NO), the operation ends. Also, step S5
In, when the control circuit 15 determines that the basket 12 has not reached the position point (in the case of NO), the operation ends.

In step S4, the control circuit 15
The car 12 moves a little after the electromagnetic brake 9 is actuated, but it can be stopped near the landing position.

[0021]

As described above, the present invention provides a current detector for detecting an input current of an electric motor for driving a car of an AC elevator, an emergency DC power supply for driving the electric motor in an emergency, and the emergency A position where the output of the current detector exceeds a predetermined value while the car is traveling at a constant speed when the electric motor is driven by the DC power supply for use, and the car is at a predetermined distance from the landing position in the hoistway. When the point is reached, the electromagnetic brake is activated to stop the car at the landing position. It has the effect of being able to stop nearby and safely rescue passengers.

[Brief description of drawings]

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

FIG. 2 is a flow chart for explaining the operation of the embodiment of the present invention.

FIG. 3 is a configuration diagram showing a conventional AC elevator control device.

FIG. 4 is a waveform diagram for explaining problems of a conventional AC elevator control device.

[Explanation of symbols]

 5 Induction motor 6 Contact 7 Battery 9 Electromagnetic brake 12 Basket 13 Current detector 15 Control circuit

Claims (1)

[Claims] 1. A current detector for detecting an input current of an electric motor for driving a basket of an AC elevator, an emergency DC power supply for driving the electric motor in an emergency, and the electric motor being driven by the emergency DC power supply. In this case, when the output of the current detector while the car is traveling at a constant speed exceeds a predetermined value and the car reaches a position point at a predetermined distance from the landing position in the hoistway, the electromagnetic brake is activated. A control device for an AC elevator, comprising a control circuit that operates to stop the basket at a landing position.