JPS6013475A - Controller of ac elevator - Google Patents

Abstract

PURPOSE:To eliminate the possibility of an electric shock by setting a regenerative power consuming circuit in a conductive state when a no-fuse breaker is interrupted, thereby discharging the stored charge of a smoothing condenser. CONSTITUTION:3-phase alternating currents are converted by a converter 3 into a direct current, smoothed by a smoothing condenser 4, converted by an inverter 6 into a variable frequency alternating current, and supplied to an AC motor 8. In case of the maintenance of an elevator, when no-fuse breakers 1, 14 are opened, the power supply to a relay 17 is interrupted, the relay 17 is dropped out, and its normal-closure contact 17a is closed. Accordingly, a transistor 5b is conducted, and the charge stored in the condenser 4 is rapidly consumed by the resistor 5.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for an AC elevator, and more particularly to a variable voltage variable frequency type elevator control device that enables rescue operation using battery power during a power outage.

The variable voltage variable frequency elevator control system that enables rescue operations during power outages includes a converter that converts alternating current to direct current (VC), a smoothing capacitor that smoothes this direct current, and a converter that converts the smoothed direct current to variable frequency alternating current. It consists of an inverter, a battery, etc. that supplies power during a power outage, but when performing maintenance by cutting off the main power supply during a power outage, the problem is that the charge accumulated in the smoothing capacitor is transferred to the DC line of the control device. is to keep it in an active state. Therefore, there is a risk of electric shock if maintenance personnel accidentally come into contact with an active DC line.

Therefore, in the past, a method has been adopted in which the accumulated charge in the smoothing capacitor is automatically discharged when a power outage or main power supply is cut off.

Figure 1 is for explaining this type of conventional AC elevator control device with a discharge function. No fuse breaker, 2a, 2b, 2c are contacts of a magnetic contactor that is energized when the AC power source is activated, 3 is a variable voltage converter that converts three-phase AC to DC, 4 is connected to the DC output end of converter 3 5 is a regenerative power circuit consisting of a series circuit of a resistor 5a and a transistor 5b, and 6 is an inverter that converts direct current into variable frequency alternating current. An AC motor 8 for driving the hoist is connected. Reference numeral 9 denotes a sheave connected to the AC motor 8 via a speed reducer (not shown). A rope 1o is wound around the sheave 9, and a cage 1 is attached to one hanging end of the sheave 9, and a fishing rod is attached to the other hanging end. The joints 12 are connected to each other. 13 is a battery for operation during a power outage connected to the AC power line of the inverter 3 through a melt no fuse breaker 14 and contactor contacts 15a, 15bf that are made during a power outage; 16 is a battery for operation during a power outage; A rectifier connected to an AC power source, 1
7 is a relay that detects whether or not the no fuse breaker 1 is cut off, which is energized by the output of the rectifier 1G when the AC power source is activated, and its normally closed contact 17a is connected in parallel between the collector and base of the transistor 5b. , normally closed contact 17a
When the regenerative power consumption circuit 5 is closed, the smoothing capacitor 4 is discharged.When the power is on, the contactor contacts 2a to 2c are closed, and when the converter is running in a straight line (during acceleration, constant lifting speed, etc.) 3 and inverter 6 operate, thereby controlling the speed of the AC motor 8 according to the speed pattern and causing the elevator car to travel. Further, during regenerative operation (during deceleration, constant lowering speed, etc.), a control circuit (not shown) turns on the transistor 5b, thereby causing the regenerative power generated from the AC motor 8 to be consumed by the resistor 5a. Note that during normal operation, the relay 17 is in the pick-up state, so its normally closed contact 17a is open.

Further, during a power outage, the contactor contacts 211 to 2c open, and the contactor contacts 151L and 1!5b close. Therefore, electric power from the battery 13 is supplied to the AC motor 8 through the converter 3 and inverter 6, and this (5) -977 drives and controls the stain motor 8, for example, to move an elevator car stopped between floors at a low speed. to run to the nearest floor. In other words, a rescue operation is performed.

By the way, in the conventional circuit as described above, when there is a power outage or the main power no fuse breaker 1 is cut off, the rectifier 1
Since the output of the transistor 5 becomes 0 and the relay 17 drops out, the normally-closed contact 17 & closes to close the transistor 5.
b becomes conductive, and the accumulated charge of the smoothing capacitor 4 is transferred to the resistor 51L.
This can protect maintenance personnel from electric shock.

However, since the relay 17 detects a power outage or the interruption of the main power supply no-fuse breaker 1 and drops out, the meter no-fuse breaker 14 was turned on so that the elevator could be rescued in the event of a power outage. In this case, the accumulated charge in the smoothing capacitor 4 is discharged through the resistor 5a, so that the voltage across the smoothing capacitor 4 increases to the battery 13.
When the voltage of the battery 13 becomes equal to the voltage of the resistor 5a, the power of the battery 13 becomes equal to the voltage of the resistor 5a.
It will be wasted. Also, when the elevator starts operating during a power outage, if the smoothing capacitor 4's charge (6) is almost completely discharged, contactor contact 1.
5&, 15b is turned on, there is a large inrush current from the battery 13 to the smoothing capacitor 4, which may cause the contacts 15a and 15b to be welded, and the diodes, etc. that make up the converter 3 may be exposed to overcurrent. There was also a risk of it being destroyed.

This invention solves the above-mentioned conventional drawbacks, and is an AC elevator that can discharge the accumulated charge of the smoothing capacitor to a state that does not pose a danger to maintenance personnel, etc., without wasting the power of the battery for operation during a power outage. to provide control equipment.

Hereinafter, specific embodiments of the present invention will be described based on the drawings.

FIG. 2 shows an example of a control device for an AC elevator according to the present invention, and the same reference numerals as in FIG. 1 represent the same parts. In addition, a rectifier 16 connected via an AC power line transformer 18 downstream of the main power no fuse breaker 1
A relay 17 is connected in parallel to the DC output end of the circuit via a backflow prevention diode 19, and this relay 17 is connected in parallel to a battery 13 for operation during a power outage through a backflow prevention diode and a melt no fuse breaker 14. The battery 13 is connected to two phases of the AC side power supply line of the converter 3 via the melt no fuse breaker 14 and contactor contacts 151L and 15b. Therefore, the relay 17 is energized by both the AC power supply and the battery 13 when the no-fuse breakers 1 and 14 are turned on, and is de-energized only when both the no-fuse breakers 1 and 14 are cut off. It is something.

In this embodiment configured as described above, during normal power supply, the main power supply no-fuse breaker 1 is turned on and the melt no-fuse breaker 14 is shut off. Relay 17 is therefore picked up by the output of rectifier 16 and its normally closed contacts 17a are open. Here, if the contactor contacts 2a to 2c are closed, the three-phase alternating current is converted to direct current by the converter 3, and the smoothing capacitor 4
After being smoothed, it is converted into variable frequency alternating current by an inverter 6 and supplied to an alternating current motor 8. Then, the speed of the AC motor 8 is controlled by the inverter 6, and the elevator is operated normally.

In addition, in the event of a power outage, the melt no-fuse breaker 14 is turned on, so power is supplied to the relay 17 from the battery 13, so that the relay 7 maintains the pickup state and its normally closed contact 17m is opened. Under normal circumstances, transistor 5b will not become conductive.

In such a state, contactor contacts 15a #15b
If the battery 13 is closed, the elevator will perform a rescue operation using electric power from the battery 13.

At this time, the accumulated charge in the smoothing capacitor 4 is not discharged through the resistor 5a and the transistor 5b, so
Even when the contactor contacts 15a s 15b are closed, no inrush current flows to the smoothing capacitor 4 as in the conventional case, and there is no risk of burning out or destroying the equipment.

During elevator maintenance, etc., use no-fuse breaker 1.
and 14, all power supply to the relay 17 is cut off, so the relay 17 drops out, and its normally closed contact 17a closes, so the transistor 5b becomes conductive, and the accumulated charge in the smoothing capacitor 4 is quickly removed by the resistor 5. consumed. Therefore, the DC line of the control circuit remains at 0 volts, and there is no risk of electric shock even if maintenance personnel touch the DC line.

That is, according to the above embodiment, the charge in the smoothing capacitor 4 is discharged only when the main power supply and melt no fuse breakers 1.14 are cut off, so that excess power is consumed from the battery. In addition, it is possible to prevent equipment from being destroyed due to rush current to the smoothing capacitor, and to protect maintenance personnel from electric shock.

FIG. 3 shows another embodiment of the invention.

The same reference numerals as in FIG. 1 represent the same parts, and 21 represents the transistor 5 &
and a base control circuit for controlling the transistor Tr of the inverter 6. The control circuit 21 is connected to the battery 13 via the melt no-fuse breaker 14, and is kept in an operating state when the no-fuse breaker 4 is turned on. As a result, the conduction of the transistor 5b of the regenerative power consumption circuit 5 is controlled until the terminal voltage of the smoothing capacitor 4 becomes equal to the voltage of the battery 13, and the conduction of the transistor Tr of the inverter 6 is controlled so that the DC side voltage (battery It is controlled so that it can be operated by changing the voltage (voltage) in 6 steps.

During normal operation of an elevator, inverter control is performed using a PWM (pulse width modulation) method that approximates a sine wave in terms of vibration and noise, so the DC side voltage may be constant regardless of the frequency, but during operation during a power outage, Since the elevator must be operated more cheaply and reliably to the nearest floor, PW
It is more advantageous to operate in 6 steps instead of using the M control method. Therefore, unless the DC side voltage is set to a frequency that matches the battery voltage, the iron core of the motor will become saturated and an overcurrent will flow, potentially damaging the inverter due to the overcurrent.

In the other embodiments described above, when a maintenance worker shuts off only the main power supply no-fuse breaker 1, the base control circuit 21 operated by the battery 13 conducts the transistor 5b, thereby turning on the smoothing capacitor 4. The accumulated charge of the battery is discharged to a voltage of ]3, and then the transistor 5b
turn off. In such a state, the voltage of the DC line is the battery voltage of 48V, so even if maintenance personnel touch the DC line, there is almost no risk of electric shock.

Note that the same effect as shown in FIG. 3 can be obtained by connecting a normally closed contact 22 in parallel between the collector and base of the transistor 5a as shown by the broken line in FIG. 3, and controlling this normally closed contact 22. It will be done.

As explained above, according to the present invention, the charge accumulated in the smoothing capacitor can be discharged to a state that does not pose a danger to maintenance personnel, etc., and there is no risk of wasting battery power as in the past. It is also possible to prevent equipment burnout and destruction due to rush current to the smoothing capacitor.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional AC elevator control device, FIG. 2 is a block diagram showing an example of an AC elevator control device of the present invention, and FIG. 3 is a block diagram of an AC elevator control device showing another embodiment of the present invention. FIG. 2 is a block diagram of a control device. 1... No fuse breaker for main power supply, 3... Converter, 4... Smoothing capacitor, 5... Regenerative power consumption circuit that also serves as smoothing capacitor discharge, 6... Converter, 8... AC motor , 9... Sheave, 11... Car, 12... Counterweight, 13... Battery, 14
... No fuse breaker for melt, 16... Rectifier, 17... Relay, 1.9 j20... Diode for backflow prevention, 21... Base control circuit. In addition, the same reference numerals in the drawings indicate the same or equivalent parts. Agent: Yu Daiwakaso (two others) Procedural amendment (voluntary) July 1980, II. 2. Title of the invention AC elevator control device 3. Person making the amendment Representative Hitoshi Katayama Department 4. Agent 5. Subject of amendment (1) Scope of claims in the specification (2) Invention in the specification Column for detailed explanation (3) Column for brief explanation of drawings in the specification (4) Drawing 6, content of amendment (1) The scope of claims in the specification is amended as shown in the attached sheet. (2) Page 4, line 13 of the specification, page 6, line 14, page 8, lines 1, 4, and 14, page 9, line 5, page 11, line 1 of the specification 2, page 13, lines 10-11, the words ``for melting'' will be corrected to ``for power outage rescue equipment.'' (3) On page 11, lines 7 to 9, the phrase "The transistor Tr... is controlled." was replaced with "The transistor Tr is controlled sequentially so that a rotating magnetic field is generated in steps. It is controlled using a so-called 6-step method.'' (4) Figure 2 of the drawing will be amended as shown in the attached sheet. 7. Attached documents (2) (1) Document stating the entire text of the amended scope of claims (1 copy) (2) Amended drawings 1 copy (3) Document stating the entire text of the amended scope of patent claims 2, Claims (1) A converter that converts alternating current into direct current, and a smoothing capacitor that smoothes the direct current from the converter. an inverter that converts the direct current to variable frequency alternating current;
An AC motor for driving the hoisting machine connected to the AC output terminal of the inverter, a circuit connected to the DC line of the converter and consuming the regenerated power of the AC motor, and a main power supply provided on the AC line of the converter. In an elevator control device comprising a no-fuse breaker for a power outage, a battery for operation during a power outage, and a no-fuse breaker for a power outage rescue device provided between the battery and the AC input terminal of the converter, Means for detecting whether or not the no-fuse breaker for the rescue device during a power outage is cut off is provided, and when both of the no-fuse breakers are cut off, the above-mentioned regenerative power consuming circuit is made conductive by the above-mentioned detection means. A control device for an AC elevator, characterized in that the accumulated charge in a smoothing capacitor is discharged. (2) The control device for an AC elevator according to claim 1, wherein the smoothing capacitor is discharged until the accumulated charge becomes close to the battery voltage. (3) The control device for an AC elevator according to claim 1, characterized in that the detection means is constituted by a relay that is energized by both an AC power source and a variable IJ. Control device. ＼ ＼ 379−

Claims (4)

[Claims] (1) A converter that converts alternating current to direct current, a smoothing capacitor that smoothes the direct current from the converter, an inverter that converts the above direct current to alternating current with variable frequency, and a hoist connected to the alternating current output end of this inverter. a driving AC motor, a circuit connected to the DC line of the converter and consuming regenerated power of the AC motor, and a main power no fuse breaker provided on the AC line of the converter;
A battery for operation during a power outage is provided, and a means is provided between the battery and the AC input terminal of the converter to detect whether or not a melt no-fuse breaker is cut off, and both of the no-fuse breakers are cut off. A control device for an AC elevator, characterized in that the detecting means brings the regenerative power consuming circuit into conduction to discharge the charge accumulated in the smoothing capacitor. (2) The control device for an AC elevator according to claim 1, wherein the smoothing capacitor is discharged until the accumulated charge becomes close to the battery voltage. (3) The control device for an AC elevator according to claim 1, wherein the detection means comprises a relay energized by both an AC power source and a battery. (4) The control device for an AC elevator according to claim 1, wherein the detection means is comprised of a control circuit that is operated by both an AC power source and a battery.