JP2001253650A - Controller of elevator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stop a car in safety by applying body of the dynamic brake and the mechanical brake in service interruption. SOLUTION: In this elevator where the alternate current is converted into the direct current by a converter, and further converted into the direct current of variable voltage by a DC chopper circuit formed by connecting a switching element and a diode inversely in parallel with each other, to be applied to a separately excited DC motor to raise a car, a field circuit of the DC motor is connected to an input side of the DC chopper circuit to energize the field circuit by the induced electromotive force returned through the diode to consume the induced electromotive force in service interruption of an AC power source.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an elevator control device for safely stopping a car during a power failure.

[0002]

2. Description of the Related Art When a power failure occurs during elevator car lifting and lowering, a mechanical brake is immediately activated to stop the car. However, when the speed at which the car moves up and down is increased, simply operating the mechanical brake alone may increase the distance the car moves up and down before stopping. Therefore, in order to increase the braking force of the hoist motor, especially in a DC motor using a permanent magnet for the field, for example,
As disclosed in Japanese Patent Application Laid-Open No. 9-9699, a system using a dynamic brake is adopted. This dynamic brake connects a resistor to the armature circuit,
The induced electromotive force generated in the armature is consumed by this resistor. Therefore, it is effective as a supplement to the mechanical brake particularly at a high speed stage.

[0003]

By the way, in a separately-excited DC motor that does not use a permanent magnet for the field, the power for the field is cut off due to a power failure, and the induced electromotive force cannot be generated in the armature. , Dynamic brake does not function effectively. For this reason, there has been a problem that the capacity of the mechanical brake must be increased, and the elevator becomes expensive.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem. In the event of a power failure, a separately-excited DC motor generates a dynamic brake and is used in combination with a mechanical brake to safely stop the car. It is intended to be.

[0005]

A first elevator control device according to the present invention converts an alternating current into a direct current by a converter, and furthermore, a variable voltage by a DC chopper circuit in which a switching element and a diode are connected in anti-parallel. In an elevator that converts the direct current to DC and applies it to a separately-excited DC motor and raises and lowers the car, when the AC power supply fails, the power failure braking circuit is activated to disconnect the elevator control circuit from the AC power supply, and the DC motor The field circuit is connected to the input side of the DC chopper circuit, and the induced electromotive force returned via the diode activates the field circuit to consume the induced electromotive force.

A second elevator control apparatus according to the present invention converts an alternating current into a direct current by a converter, smoothes the current by a smoothing capacitor, and furthermore, a variable voltage by a DC chopper circuit in which a switching element and a diode are connected in anti-parallel. In an elevator that converts the direct current to DC and applies it to a separately-excited DC motor and raises and lowers the car, when the AC power supply fails, the power failure braking circuit is activated to disconnect the elevator control circuit from the AC power supply, and the DC motor Field circuit D
The field circuit is energized by both the induced electromotive force returned via the diode connected in parallel with the smoothing capacitor to the input side of the C chopper circuit and the charging power of the smoothing capacitor so that the induced electromotive force is consumed. It was done.

According to a third elevator control device of the present invention, in the first or second elevator control device, when the power transmission is restarted, the field current due to the induced electromotive force becomes equal to or less than a predetermined value. Sometimes, the field circuit connected to the input side of the DC chopper circuit is cut off from the DC chopper circuit.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 1 and 2
Embodiment 1 Embodiment 1 of the present invention will be described. In FIG. 1, 1 is a three-phase AC power supply, 2 is an IGBT (Insulated Ga
A converter consisting of a combination of a te Bipolar Transistor and a diode, which performs both forward conversion from three-phase AC to DC and reverse conversion for converting the electromotive force generated during normal operation to the three-phase AC power supply 1 as regenerative power. Make it possible. Reference numeral 3 denotes a smoothing capacitor for smoothing the DC output converted by the converter 2, and reference numeral 4 denotes a circuit element in which an IGBT and diodes D1 to D4 are connected in anti-parallel to each other in a bridge form. This is a DC chopper circuit that performs DC voltage control in both reverse directions.

Reference numeral 5 denotes a DC motor controlled by the DC chopper circuit 4; 5a, an armature of the DC motor 5; 5f, a field winding; 6, a transformer connected to the three-phase AC power supply 1;
Is a rectifier circuit for converting AC to DC. Reference numeral 9 denotes a rotary shaft directly connected to the DC motor 5, reference numeral 10 denotes a hoisting machine connected to the rotary shaft 9, reference numeral 11 denotes a mechanical brake for decelerating and stopping the rotary shaft 9, and furthermore, reference numeral 12 denotes hoisting. A main rope 13 wound around the machine 10, a basket 13 suspended at one end of the main rope 12, and a counterweight 14 suspended at the other end of the main rope 11.

Reference numeral 21 denotes an encoder mounted on the rotating shaft 9;
Reference numeral 22 denotes a speed detection circuit for detecting the rotation speed n of the rotary shaft 9 from the encoder 21; 23, a speed pattern generation circuit for generating a speed pattern for raising and lowering the car 13; A comparison circuit for comparing the speed pattern with the speed pattern; 25, a PWM circuit for generating a PWM signal based on the comparison result by the comparison circuit 24;
6 is a DC chopper circuit 4 according to a signal of the PWM circuit 25.
Is a gate drive circuit that controls ON / OFF of the gate of the IGBT.

Reference numeral 30 denotes a power failure braking circuit that controls the elevator during a power failure. Among them, 31 is a DC current transformer for detecting a current flowing through the field winding 5f during a power failure, 32 is a field current detection circuit for detecting the field current If from the DC current transformer 31, and 32a is a field current detection circuit A normally closed contact that is opened when the field current If detected by the circuit 32 exceeds a predetermined value δ, and closed when the field current If is equal to or less than the predetermined value, and 33 is when the three-phase AC power supply 1 is transmitting power. Is energized to normally open contact 33a,
33b and 33c are closed, and normally closed contacts 33d and 33e are closed.
A contactor that opens the contactor. Reference numeral 34 denotes a resistor for limiting the current from the buses (+) and (-) to the field winding 5 during a power failure. Vc is a bus voltage between the buses (+) and (−),
Vm is a terminal voltage of the armature 5a.

Next, the operation will be described. 1. Normally, the contactor 3
3, the normally open contact 33a is closed to form a self-holding circuit. By closing the normally open contact 33b, a three-phase AC is supplied to the converter 2, and a DC bus (+)-
Between (−) is smoothed by the smoothing capacitor 3 and the bus voltage V
m DC is generated. When the normally open contact 33c is closed, an alternating current is supplied to the rectifier circuit 7 via the transformer 6, and a field current If flows through the field winding 5f.

When a start command is issued, a predetermined speed signal is output from the speed pattern generation circuit 23, and a comparison circuit 24
Is compared with the actual speed. PWM based on the comparison result
A PWM signal is generated from the circuit. The gate drive circuit 26 turns on the DC chopper circuit 4 in accordance with the PWM signal.
-OFF control, voltage-controlled DC is applied to the DC motor 5, and the car 12 is raised and lowered to the destination floor.

2. As shown in FIG. 2, the bus voltage Vc is Vc0 and the terminal voltage V
It is assumed that m is Vm0, the field current If is If0, and the rotating shaft 9 is rotating at a constant speed of the rotational speed n0 to move the car 13 up and down. (1) When a Power Failure Occurs (Time t1) It is assumed that a power failure occurs at time t1 during ascent and descent in the above state.
The contactor 33 is deenergized, the normally open contact 33b is opened, and the converter 2 is disconnected from the three-phase AC power supply 1. Also,
By opening the normally open contact 33c, the rectifier circuit 7 is also disconnected from the AC power supply. Therefore, at time t1 immediately after the occurrence of the power failure, the normally closed contacts 33d and 33e are closed, and the resistor 34 is closed.
, The bus voltage Vc0 is applied to the field winding 5f.
Since the bus voltage Vc0 is higher than the field voltage by the rectifier circuit 7, the field current If is equal to the previous field current If.
Increases from 0 to If1. The induced electromotive force increases due to the increase in the field current If, and the terminal voltage Vm increases from Vm0 to Vm1.

(2) Times t1 to t2 On the other hand, when a power failure occurs, the mechanical brake 11 operates, and the rotating shaft 9 starts to decelerate from the rotation speed n0. The bus voltage Vc is maintained by the charging power of the smoothing capacitor 3, and the initial bus voltage Vc0 is higher than the terminal voltage Vm1. Therefore, the induced electromotive force generated in the armature 5a is not consumed, and the car 13 is decelerated only by the mechanical brake 11. However, although the charge of the smoothing capacitor 3 is prevented from flowing into the armature 5a by the DC chopper circuit 4, the field current If
, The bus voltage Vc becomes the initial value V
It is smaller than c0. Further, the terminal voltage Vm is also equal to the rotational speed n.
And the reduction of the field current If, the value becomes smaller than the value Vm1 at the beginning of the power failure.

(3) Time t2 As the field current If is discharged from the smoothing capacitor 3, the bus voltage Vc decreases rapidly and becomes equal to the terminal voltage Vm2 at time t2 after a short time. At this time, the rotation speed n is set to n1, and the field current If is set to If2.

(4) Time t2 to t3 After time t2, the field current If is supplied from both the smoothing capacitor 3 and the induced electromotive force in the armature 5a. For this reason, the reduction rate of the field current If between the times t2 and t3 is:
It becomes smaller than between times t1 and t2. The same applies to the terminal voltage Vc. However, the terminal voltage Vm is reduced by a part of the field current If,
growing. In addition, since a part of the induced electromotive force is consumed as the field current If by the field winding 5f, the power generation braking is added to the braking by the mechanical brake 11, and the rotation speed n rapidly decreases after time t2. . However, the rotation speed n
As the field current decreases, the field current If also decreases, and the dynamic braking decreases. The braking is mainly decelerated by the mechanical brake 11, and the rotating shaft 9 stops at time t3. That is, it stops at time t3, which is shorter than time t4 when it is expected to stop only with the mechanical brake 11.

(5) Restart of power transmission When the power transmission is restarted, the field current If is lower than the predetermined value δ. When the power transmission is restarted, when the field current If is lower than the predetermined value δ, the power supply is normally closed. The contact 32a is closed. For this reason, the contactor 33 is urged through the normally closed contact 32a to close the normally open contact 33a, to form a self-holding circuit, and to close the normally open contact 33b to the converter 2 to apply three-phase AC to the converter 2. To close the normally open contact 33c to supply alternating current to the rectifier circuit 7 to excite the field winding 5f. In this state, when a speed pattern is generated from the speed pattern generation circuit 23 based on the start command, the car 13 is operated according to this pattern and moves up and down to the destination floor. That is, the state returns to the normal state. When power transmission is restarted, field current If exceeds predetermined value δ When power transmission is restarted, when field current If exceeds predetermined value δ, normally closed contact 32a is open. Therefore, the contactor 33 remains unenergized, the converter 2 and the rectifier circuit 7 are both disconnected from the AC power supply, and the power failure state is maintained. However, when the field current If has a predetermined value δ
By decreasing below, the normally closed contact 32a is closed, and thereafter returns to the normal state as described above.

According to the first embodiment, when a power failure occurs, the contactor 33 of the power failure braking circuit 30 is deenergized, the normally open contacts 33d and 33e are closed, and the field winding 5f is connected to the bus (+ ) And (−) are excited by the charging power of the smoothing capacitor 3. For this reason, when the car 13 is operating at high speed at the time of a power failure, induced electromotive force is generated in the armature 5a by exciting the field winding 5f. This induced electromotive force is converted back to the bus (+) and (-) sides through the DC chopper circuit 4 and consumed by the field winding 5f. Therefore, in addition to the mechanical brake 11, the electric braking is applied. The car 13 can be stopped at a short distance as compared with the case where only 11 is used. In addition, since the charging power of the smoothing capacitor 3 is used, it is possible to generate the power generation braking from the initial stage of the substantially high-speed operation, and it is not necessary to separately provide a discharging circuit of the smoothing capacitor 3.

Further, when the power transmission from the three-phase AC power supply 1 is resumed, the contactor 33 is energized after the field current If becomes equal to or less than a sufficiently small predetermined value δ, and the normally closed contacts 33d and 33 are turned on.
e is opened, and the field winding 5f is cut off from the buses (+) and (-), so that there is substantially no current interruption. Therefore, the normally closed contacts 33d and 33e are not welded. Furthermore, since the armature 5a is connected to the buses (+) and (-) via the DC chopper circuit 4, even if the DC motor 5 reversely rotates and the polarity of the terminal voltage Vm changes, the DC chopper circuit 4 The current is rectified by the diodes D <b> 1 to D <b> 4 and a direct current in a certain direction is always returned to the buses (+) and (−). For this reason,
There is no need to separately provide a switching circuit for matching the polarity of the terminal voltage Vm with the polarity of the bus voltage Vc.

Embodiment 2 FIG. In the first embodiment, the smoothing capacitor 3 is connected to the buses (+) and (−) and uses the charging power. However, the smoothing capacitor 3 is not always necessary. That is, in the separately-excited DC motor 5, the field winding 5f is always excited by a DC voltage in a fixed direction, so that even if a power failure occurs and the exciting current If becomes "0", a fixed remanence exists. . Therefore, if the DC motor 5 is rotating, a residual voltage is generated in the armature 5a. If this residual voltage is returned to the bus (+) and (-) sides via the DC chopper circuit 4 to excite the field winding 5f, the induced electromotive force of the armature 5a is increased to generate power braking. Can be applied.

According to the second embodiment, the dynamic braking can be applied in addition to the mechanical brake 11. Therefore, the car 13 can be stopped at a short distance as compared with the case where only the mechanical brake 11 is used.

[0023]

Since the present invention is configured as described above, it has the following effects. The first elevator control apparatus according to the present invention converts AC into DC by a converter, and further converts the AC into DC of a variable voltage by a DC chopper circuit in which a switching element and a diode are connected in anti-parallel to separately-excited. In an elevator that applies a voltage to a DC motor and raises and lowers a car, when an AC power supply fails, a power failure braking circuit is activated to disconnect the elevator control circuit from the AC power supply and to connect a DC motor field circuit to a DC chopper circuit input. The field circuit is energized by the induced electromotive force returned through the diode connected to the side and consumes the induced electromotive force. For this reason, if a power failure occurs while the car is running at high speed, the mechanical brake is applied with dynamic braking and decelerated, so that the car can be stopped more quickly than in the case where only the mechanical brake is used. To play.

A second elevator control apparatus according to the present invention converts an alternating current into a direct current by a converter, smoothes the current by a smoothing capacitor, and furthermore, a variable voltage by a DC chopper circuit in which a switching element and a diode are connected in anti-parallel. In an elevator that converts the direct current to DC and applies it to a separately-excited DC motor and raises and lowers the car, when the AC power supply fails, the power failure braking circuit is activated to disconnect the elevator control circuit from the AC power supply, and the DC motor Field circuit D
The field circuit is energized by both the induced electromotive force returned via the diode connected in parallel with the smoothing capacitor to the input side of the C chopper circuit and the charging power of the smoothing capacitor so that the induced electromotive force is consumed. It was done. For this reason, even in this case, the car can be stopped quickly as described above, and since the charging power of the smoothing capacitor is used, the power generation braking can be generated from almost the initial stage of the power failure occurrence. It has the effect of being able to.

According to a third elevator control device of the present invention, in the first or second elevator control device, when the power transmission is restarted, the field current due to the induced electromotive force becomes equal to or less than a predetermined value. Sometimes, the field circuit connected to the input side of the DC chopper circuit is cut off from the DC chopper circuit. For this reason, there is an effect that there is substantially no current interruption and the field circuit can be easily cut off.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an overall configuration of an elevator control device according to Embodiment 1 of the present invention.

FIG. 2 is an operation explanatory diagram of the first embodiment of the present invention.

[Explanation of symbols]

1 three-phase AC power supply, 2 converter, 3 smoothing capacitor, 4 DC chopper circuit, 5 DC motor,
5a armature, 5b field winding, 6 transformer,
7 rectifier circuit, 9 rotating shaft, 10 hoisting machine, 1
1 mechanical brake, 12 main ropes, 13 cars, 14 counterweights, 21 encoders, 2
2 speed detection circuit, 23 speed pattern generation circuit,
24 comparison circuit, 25 PWM circuit, 26 gate drive circuit, 30 power failure braking circuit, 31 DC current transformer, 32 field current detection circuit, 32a normally closed contact
33 contactor, 33a normally open contact, 33b normally open contact, 33c normally open contact, 33d normally closed contact, 33e
Normally closed contact, 34 resistor, (+) bus, (-)
Busbar.

Continued on the front page F term (reference) 3F002 EA01 EA04 EA09 GB02 3F304 CA05 EA18 5H530 AA14 BB26 CC08 CC26 CE02 CE15 CE22 DD05 DD15 DD19 EE07 EF03 5H571 AA09 BB10 CC05 CC09 DD01 EE02 FF02 FF06 GG02 HA08 HC01 PP02

Claims (3)

[Claims] 1. A separately-excited DC motor which converts an AC of an AC power supply into a DC by a converter, and further converts the DC into a variable-voltage DC by a DC chopper circuit in which a switching element and a diode are connected in anti-parallel. In the elevator control device that raises and lowers the car, when the AC power is cut off, the AC power is cut off, and the field circuit of the DC motor is connected to the input side of the DC chopper circuit to connect the diode. An elevator control device including a power failure braking circuit for energizing the field circuit with the induced electromotive force returned through the power supply and consuming the induced electromotive force. 2. An AC power supply of an AC power source is converted into DC by a converter, smoothed by a smoothing capacitor, and further converted into a variable voltage DC by a DC chopper circuit in which a switching element and a diode are connected in anti-parallel, and separately excited. In the elevator control device for applying a voltage to the DC motor and raising and lowering the car, when the AC power is cut off, the AC power is cut off, and the field circuit of the DC motor is connected to the smoothing capacitor on the input side of the DC chopper circuit. And a power failure braking circuit for activating the field circuit with both the induced electromotive force returned through the diode and the charging power of the smoothing capacitor to consume the induced electromotive force. Elevator control device. 3. A power failure braking circuit, comprising: a field circuit connected to an input side of a DC chopper circuit when power transmission is resumed and a field current due to induced electromotive force becomes a predetermined value or less. Claim 1 wherein the chopper circuit is cut off.
Or the elevator control device according to claim 2.