JPS59172984A - Controller of ac elevator - Google Patents

Abstract

PURPOSE:To prevent a danger of electric shock for a maintenance worker or the like by conducting a semiconductor element for processing regenerative power when an AC power source failure is detected and discharging the charge of a smothing condenser. CONSTITUTION:When an AC power source 1 is normal and a breaker 2 is energized, a power source failure detector relay 12 is energized, and a contact 12a is opened. When the terminal voltage of a smoothing condenser 4 is raised by the regenerative power from a motor 6 in this case, a base drive circuit 10 generates an output, and a transistor 8 is conducted to consume the regenerative power by a resistor 7. When the breaker 2 is interrupted or the power source 1 is interrupted, the relay 12 is deenergized to close the contact 12a, and the transistor 8 is conducted by the charge stored in a capacitor 19. In this manner, the stored charge of the condenser 4 is quickly discharged, and the terminal voltage drops.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a device for controlling an AC elevator.

For example, Japanese Unexamined Patent Application Publication No. 132275/1983 discloses a system in which an induction motor is used in an electric car that drives an elevator car, and an inverter supplies alternating current power of variable voltage and frequency to operate the car. There is. FIG. 1 shows a system in which a device for processing the regenerative power of the electric motor is added to this system.

In the figure, (1) is a commercial three-phase AC sound source, and (2) is an AC power source (
1) is the circuit breaker connected to circuit breaker (2), (3) is the circuit breaker connected to circuit breaker (2)
A converter (4) is a smoothing capacitor connected to the DC side of the converter (3), which is connected to a converter (4) consisting of diodes that form a three-phase full-wave rectifier circuit, and converts three-phase AC into DC.
(5) is a well-known PWM type inverter that is connected to a smoothing capacitor (4) and is composed of transistors and diodes, and converts a constant DC voltage into an AC voltage with variable voltage and variable frequency by controlling the pulse width. Three-phase induction motors (7) and (8) connected to the AC side of the inverter (5) and driving the elevator heel (not shown) via a drive sheave (not shown) are connected in series with each other. A resistor and a transistor connected to the DC side of the inverter (5), (
9) is a voltage detection circuit α0 that is connected to both ends of the smoothing capacitor (4) and outputs an output when the voltage exceeds a predetermined value.
is a base drive circuit which is operated by the output of the voltage detection circuit (9) and provides a conduction signal to the base of the transistor (8).

That is, the smoothing capacitor (4) is charged by the DC voltage converted by the converter (3), and when the voltage reaches a certain value, the transistors of the inverter (5) are sequentially turned on in the driving direction. Generates variable voltage/variable frequency alternating current power in corresponding phase sequence. The electric motor (6) is now started in the direction determined by the phase sequence of the inputs, and the car starts running. In this case, during heavy load ascending operation, light load descending operation, etc., electric power is supplied to the electric motor (6), but during heavy load descending operation, light load increasing operation, etc., electric power is regenerated by the electric motor (6), and this is On the other hand, the inverter (
5). In such a case, the DC side voltage of the inverter (5) increases and becomes a voltage higher than the withstand voltage of the elements of the inverter (5) or converter (3).
There is a possibility that the element may be destroyed. Therefore, when the terminal voltage of the smoothing capacitor (4) exceeds a predetermined value, the voltage detection circuit (9) issues an output, the base drive circuit 00 operates, and the transistor (8) becomes conductive.

As a result, the regenerated power is consumed through the resistor (7),
Destruction of the element is prevented.

However, even if the circuit breaker (2) is shut off during maintenance, etc., the terminal voltage of the smoothing capacitor (4) remains high for a considerable period of time, so there is a risk of electric shock if maintenance personnel come into contact with it. be.

This invention prevents the above-mentioned problem, and when loss of AC power is detected, connects the charged second capacitor to the semiconductor element for regenerative power processing and conducts it, thereby replacing the smoothing capacitor. An object of the present invention is to provide a control device for an AC elevator that can discharge electricity to ensure the safety of maintenance personnel and the like.

An embodiment of the present invention will be described below with reference to FIG.

In the figure, (2) is connected to the circuit breaker (2) and the AC power supply (1)
A power loss detection relay that is energized when the AC power supply (1) is turned on and deenergized when the AC power supply (1) is cut off. (12a) is its normally closed contact, αa is the base drive circuit power supply device, and 04'l is the AC power supply [1) K
The secondary winding of the connected transformer (not shown), αυ~(
(to) is a diode that full-wave rectifies the alternating current supplied from the secondary winding α to provide direct current power to the base drive circuit (9), and the wire is connected to both ends of the direct current side of the full-wave rectifying circuit, respectively. Connected between secondary winding α→neutral wire and base drive circuit 0
The second capacitor, Q]), which smoothes the power supply to A conductive circuit (a) is formed by connecting the

Note that one of the output lines of the base drive circuit (11) is connected to the base of the transistor (8), and the other output line, the neutral line of the transformer secondary winding α, is connected to the emitter side of the transistor (8). It is connected to the.

Other than the above, the configuration is the same as in FIG. 1.

Next, the operation of this embodiment will be explained.

When the AC power supply (1) is normal and the circuit breaker (2) is turned on, the power loss detection relay 02 is energized and the contact (
12a) is open. The operation in this case is similar to that shown in FIG. In other words, when the terminal voltage of the smoothing capacitor (4) increases due to the regenerated power from the motor (6), the base drive circuit 00 emits an output, the transistor (8) becomes conductive, and the regenerated power is consumed by the resistor (7). be done.

When the circuit breaker (2) is tripped or the AC power supply (1) is interrupted, the power loss detection relay (2) is deenergized and the contact (
12a) is closed. Now, Q'e - (12a)
-621) -(8) A circuit of 〇〇 is formed, and the transistor (8) becomes conductive due to the charge accumulated in the second capacitor α9.

As a result, the accumulated charge of the smoothing capacitor (4) is rapidly discharged in the circuit (4)-(f)-(8)-(4), and the terminal voltage thereof decreases. Therefore, electric shock accidents are prevented.

As explained above, in the present invention, when loss of AC power is detected, the charged second capacitor is connected to the semiconductor element for processing regenerative power from the elevator induction motor to make it conductive. Therefore, the electric charge of the smoothing capacitor can be discharged through the semiconductor element and the terminal voltage thereof can be lowered, and the risk of electric shock to maintenance personnel and the like can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing a conventional AC elevator control device, and FIG. 2 is a circuit diagram showing an embodiment of an AC elevator control device according to the present invention. (1) Commercial three-phase AC power supply, (2) Molded circuit breaker, (3) Converter, (4) Smoothing capacitor, (5) Inverter, (6 )...Three-phase induction motor, (8)...Transistor, (9)...Voltage detection circuit, 00...Base drive circuit, α''2...
Power loss detection relay, (I4)...Transformer secondary winding,
α9-a (to)...Diode, 0e...Second capacitor, (A)...Conduction circuit Note that the same reference numerals in the drawings indicate the same parts. Agent Shin Kuzuno - (1 other person) Figure 1 Figure 2 Procedural amendment (voluntary) 1. Indication of the case Patent Application No. 1988-4'/4'70 No. 2
・Name of the invention: AC elevator control device 3, relationship with the amended case Patent applicant address: 2-2-3 Marunouchi, Chiyoda-ku, Tokyo Name (601) Jinhachibe Katayama, Representative of Mitsubishi Electric Corporation 4. Agent address: 2-2-3-5 Marunouchi, Chiyoda-ku, Tokyo
, column 6 of the detailed description of the invention in the specification to be amended, and the description of the contents of the amendment, are corrected as follows. (2)

Claims (1)

[Claims] A smoothing capacitor, a series circuit of a resistor and a semiconductor element, and an inverter are each connected in parallel to the DC side of the converter connected to an AC power supply, and the output of this inverter drives an induction motor to operate the car. , wherein the regenerative power of the motor is consumed through the resistor by making the semiconductor element conductive, a power loss detection device that operates when the AC power source is lost; capacitor,
and a control device for an AC elevator, comprising a conduction circuit that connects the second capacitor to the semiconductor element and makes it conductive when the power loss detection device operates.