JPS6175780A - Speed controller for alternating current elevator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a device for controlling the speed of an AC elevator driven by an induction motor.

[Conventional technology]

Among AC elevators driven by induction motors, an AC feedback control system is used for speed control of medium-speed and low-speed elevators with a rated speed of 105 m/min or less.

This is, for example, Mitsubishi Electric Technical Report, 52 [4] (Sho 53-4
-25) p, 323 in FIG. 5, this will be explained with reference to FIG.

In the diagram, (1) is a three-phase AC power supply, (2) is an AC power supply (1)
(3) is also a braking control thyristor device, (4) is a three-phase induction motor connected to (2) + (3), and (5) is a braking control thyristor device connected to (2) + (3). is directly connected to the electric motor (4).
(6) is a speed detector consisting of a speedometer-developed electric machine that emits a speed signal 8 (5a) corresponding to the rotational speed of the electric motor (4); (6) is a speed reducer that decelerates the rotation of the electric motor (4); (7)
is the drive sheave connected to the output shaft of the reducer @ (6), (8)
is an electromagnetic brake that applies braking force to the sheave (7), (9) is the main rope wrapped around the sheave (7), αO is the cage connected to one end of the main rope (9), and (loa) is the A car position signal is output when a position detector (not shown) installed in car α4 detects a position point in the hoistway. A speed command generator that inputs a position signal (LOA) and issues a speed command signal (12a) according to the car position. An adder that compares and generates a deviation signal (13a), α→ is a deviation signal (13a)
When the output of amplifier α→ is positive, it amplifies the signal (15a), and when it is negative, it amplifies the signal (15b).
), αQ is a power firing control circuit that operates according to the signal (15a) and controls the firing of the power row control thyristor device (2), and αη is a braking control thyristor device that operates according to the signal (15b). (3) A brake ignition control circuit that controls e-ignition, that is, a speed command signal (12a) and a speed signal (5a)
) When the deviation m (13a) of be done. The rotation of the electric motor (4) is reduced by a speed reducer (6) to drive the sheave (7), and the speed of the car αO is controlled via the main rope (9). When the deviation signal (13a) is negative, the brake firing control circuit αη operates to control firing of the brake control thyristor device (3), and the motor (4) is controlled with DC braking current to decelerate.

When the car αO is running at the rated speed, in order to reduce the heat generation and power consumption of the electric motor (4), the car row control thyristor device (2) is fully turned on, and the full three-phase voltage is applied to the electric motor (4). and the electric motor (4) is rotating near its synchronous speed. V shown in the speed command generator (2) is a rated speed command value corresponding to the above-mentioned rated speed. After all, in this elevator, the maximum speed of the car αO is the speed when the car row control thyristor device (2) is fully fired, that is, the rated speed.

[Problem that the invention seeks to solve]

When there are no passengers in car αO, call αO at the landing.
When calling a car, there is almost no danger in running the car αO at a speed higher than the rated speed. However, with the conventional AC elevator speed control device as described above, there is a problem in that it is impossible to run the car αO at a speed higher than the rated speed, and the operating efficiency cannot be improved.

This invention was made to solve the above problems, and is an AC elevator that allows the car to run at a speed higher than the rated speed when there is no load inside the car, thereby increasing the operating efficiency. The purpose is to provide a speed control device.

[Means for solving problems]

The speed control device for an AC elevator according to the present invention supplies an AC of variable voltage and variable frequency to an induction motor so that the car runs at a speed higher than the rated speed when there is no load in the car. It is something.

[Effect]

In the AC elevator speed control device of this invention,
When there is no load in the car, the frequency of alternating current supplied to the electric motor is increased to increase the speed of the car and shorten the time it takes to answer a call.

〔Example〕

FIG. 1 is a block diagram of an embodiment of the present invention (1).

(4) to α] are the same as in FIG.

In the diagram? The sword is a converter that is connected to an AC power source (1) and forms a three-phase full-wave rectifier circuit using diodes (A).
121) is a smoothing capacitor connected to the DC side of the converter 121), and 121) is an inverter connected to the smoothing capacitor (A). Three sets of two transistors connected in series are connected in parallel, and these transistors Each circuit is composed of a circuit in which diodes are connected in parallel. (To) is a load detection device installed in the car αO, which is composed of a differential transformer, etc., and outputs a load signal (24IL) corresponding to the load in the car and gives it to the speed command generator, and (5) is a deviation signal. (13a) is a well-known PWM control circuit that converts a constant DC voltage into a variable voltage/variable frequency alternating current by controlling the transistors of the center-temperature converter using pulse width modulation (PWM). , an inverter (g), and a PWM control circuit (c) are shown, for example, in FIG.

Next, the operation of this embodiment will be explained.

Three-phase AC power is converted to DC by Compartur D,
The inverter is smoothed by a smoothing capacitor (c)
given to. The inverter (c) is controlled by the PWM control circuit (to) and generates a variable voltage/variable frequency alternating current with a sum term corresponding to the driving direction. Now the electric motor (4
) rotates, and the car α0 is rotated N as in the case of FIG.

As is well known, when the input voltage/frequency of the electric motor (4) is kept approximately constant, a predetermined torque can be obtained at any speed. Furthermore, since the maximum speed is determined by the slip frequency, the speed can be increased by increasing the supply frequency.

Now, when there is no negative load inside the car αO, a corresponding load signal (Z4a) is output. In the speed command generator (2), the rated speed command value V of the speed command signal (12a) is set to 1.1Vtp by the load signal (24a).
Increase by p. As a result, the speed of car uO becomes 110% of the rated speed, but since there are no passengers in car αQ,
There is little danger. Of course, for the safety of the elevator itself, the speed of the car uO is set to the rated speed 17)l1596
When the speed reaches a certain level, a speed governor (not shown) is activated and the car uO suddenly stops. However, when there is no load, there is no problem in increasing the speed to about 110% of the rated speed.

In this way, when there are no passengers in the car uO, when the car uO is called for by a call from the landing, the car uO runs at a speed higher than the rated speed and answers the call 8 times, increasing the operating efficiency.

In addition to using a differential transformer, the load detection device ■ also uses a detection means using image processing using a camera installed inside the car.
A detection device using infrared rays or ultrasonic waves may also be used.

〔Effect of the invention〕

As described above, in this invention, variable voltage and variable frequency alternating current is supplied to the induction motor that drives the elevator car, so that the car runs at a speed higher than the rated speed when there is no load in the car. This has the effect of shortening the time it takes to answer six calls and increasing operational efficiency.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of an AC elevator speed control apparatus according to the present invention, and FIG. 2 is a block diagram showing a conventional AC elevator speed control apparatus. In the figure, (1) is a three-phase AC power supply, (4) is a three-phase induction motor, uO is a cage, @ is a speed command generator, C is a converter, □□□ is an inverter, and (c) is a load detection device. , (to) is a PWM control circuit. Note that the same reference numerals in the figures indicate the same or equivalent items.

Claims (1)

[Claims] (1) A converter converts AC power into DC, an inverter converts it into AC with variable voltage and variable frequency, and supplies it to the induction motor, and adjusts the rotation speed of the motor according to the speed command signal to drive the car. A load detection device that outputs an output when the load in the car is unloaded, and when this load detection device generates the output, it corresponds to a speed higher than the rated speed of the car. A speed control device for an AC elevator, comprising a speed command generation circuit that generates the speed command signal described above.