JPS5866598A - Drive device for ac elevator - Google Patents

Abstract

PURPOSE:To regenerating the electric power to a power source without providing an exclusive regenerative inverter by commonly using a converter and a regenerative inverter. CONSTITUTION:When a motor 8 is power driven, operating solenoid contactor contacts 19a, 19b are closed, and switching solenoid contactor contacts 20a, 20b are opened. A firing circuit 16 controls the phases of thyristors 4a-4f so that the converter 4 is operated as the rectifier. AC power of variable voltage and variable frequency is supplied to the motor 8. In case that the motor 8 is regeneratively braked, when an over voltage detector 13 produces an output, a switching unit 21 operates to close the contacts 20a, 20b, and to open the contacts 19a, 19b. Simultaneously, a firing circuit 16 controls the phases of thyristors 4a-4f so that the converter 4 may operate as an inverter. The regenerative power generated at the motor 8 is returned through the converter 4 to the power source 1.

Description

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

An induction motor is used as an electric motor for driving an elevator car, and the electric motor is driven by supplying variable voltage, variable frequency AC power converted by an inverter. In this case, when the car is under regenerative braking, such as when the car is lowering a heavy load, increasing a light load, or decelerating, regenerative power is generated, so a device is required to regenerate this power into a power source. This is the first
As shown in the figure.

In the figure, (1) is a three-phase AC power supply, (2) is a conversion device consisting of a voltage source inverter that converts constant frequency AC power into variable frequency AC power, and (3) is connected to the AC power supply (1). A regenerative inverter composed of thyristors (3a) to (3f), (4) is connected to the AC power supply (1) and the DC side of the regenerative inverter (3), and the thyristor (4a) to
(4f) is a converter, (5) is a smoothing capacitor connected between the DC terminals of converter (4), (6) is a voltage detection device also made of a resistor, and (7) is a converter (4). A transistor (′
7A) to (7F) and diodes ('7a) to (7f), and is a well-known pulse width modulation type inverter that converts a constant DC voltage into AC of any voltage and any frequency; (8) is an inverter ( 7) is a three-phase induction motor connected to the downstream side, (9) is a hoist-like drive sheave driven by the motor (8), (10 is a main rope wound around the sheave (9)) , (11), (12) are the heels and counterweights connected to both ends of the main rope 0, 03) is the overvoltage detection device connected to the voltage detection device (6), and (14) is the overvoltage detection device ( +3) output drives the regenerative inverter (
The ignition circuit (16) that controls the phase of the thyristors (main) to (3f) in 3) or the thyristor (4a) in the converter (4)
) to (4f), the phase control device t and (17) that operate the ignition circuit (16) that controls the phase of the transistors (7A) to (7F) are distributors that control on/off of the transistors (7A) to (7F) of the inverter (7).

That is, when the electric motor (8) is in power mode, the overvoltage detection device θ barrel does not output an output, the phase control device (14) operates the ignition circuit (+6), and the thyristor (4a) of the converter (4) ) to (4f) are phase-controlled and act as rectifiers. AC power from AC power supply (1) is converted to converter (4)
Since the AC power is rectified by the inverter (7) and supplied to the inverter (7), the electric motor (8) is supplied with alternating current power of variable voltage and variable frequency. with this,! The motive (8) is driven and the car (l
Su is running.

When the induction motor (8) rotates at a rotational speed higher than the synchronous speed, such as during braking, it operates as a generator. The terminal voltage of the capacitor (5) increases,
There is a risk of damaging the semiconductor element. Therefore, when the terminal voltage of the smoothing capacitor (5) rises above a predetermined value, the overvoltage detection device (13) emits an output and the ignition circuit (1
5) works. With this, the phases of the regenerative inverter (3) (3a) to (3f) are controlled, and the regenerative power is returned to the power source (1) via the regenerative inverter (3). This prevents an increase in the terminal voltage of the smoothing capacitor (5).

However, when driving a large-capacity electric motor (8) with large regenerative power, such as a double series, the regenerative inverter (3)
Therefore, the conversion device (2) becomes expensive.

However, when using a small-capacity induction motor with low regenerative power, the regenerative power is configured to be consumed through a resistor (not shown). In this case, the regenerative inverter (
Although 3) is unnecessary, since the regenerated power is not returned to the power source (1), an increase in power consumption is unavoidable.

The present invention aims to improve the above-mentioned problems, and provides an AC elevator drive device that can regenerate power to a power source without providing a dedicated regeneration inverter by sharing a converter and a regeneration inverter. With the goal.

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

In the figure, (19a) and (19b) are operating electromagnetic contactor contacts inserted into the connection line between the converter (4) and inverter (7), and (20a) and (20b) are the contacts of the converter (4) and inverter (7). ) is a switching electromagnetic contactor contact that connects to the opposite polarity, and υ is a switching device that is connected to an overvoltage detection device (connection) and controls the operation of the electromagnetic contactor.Others are the same as in Fig. 1.However, , a regeneration inverter (3) is not provided.

Next, the operation of this embodiment will be explained.

When the electric motor (8) is running, there is a magnetic contactor contact (1 a) for operation.

(19b) is closed and the switching magnetic contactor contact (zoa,
), (20b) are open. The ignition circuit (+6fl) controls the phase of the thyristors (4a) to (4f) so that the converter (4) performs its original rectifying action.The motor (8) now receives variable voltage and variable frequency AC power. Supplied.

When the overvoltage detection device 03) outputs an output during regenerative braking of the electric motor (8), the switching device 12]) operates and the contact (2)
0a).

(20b) is closed, and the contacts (19a) and (19b
) is open.

At the same time, the ignition circuit αXin controls the phase of the thyristors (4a) to (4f) so that the converter (4) performs an inverter operation. With this, the regenerated power generated in the electric motor (8) is returned to the power source (1) via the converter (4) without providing a dedicated regeneration inverter.

Note that the contacts (19a), (19b) and the contact (20a)
, (20b), the current flowing through the converter (4) is small, so the contacts (19a), (19b),
For (20a) and (20b), inexpensive ones with small current interrupting capacity can be used.

FIG. 3 shows another embodiment of the invention, in which a plurality of elevators are operated in parallel.

In the figure, ('7x) to (75) are inverters connected in parallel with each other and connected to the DC side of converter (4), and (8
1) ~ (85), (91) ~ (95), (101) ~
(105), (111)-(115).

(121) to (125) are three-phase B conductive motors, respectively.

The main rope, the cage and the counterweight. The rest is the same as in FIG. 2.

When performing parallel operation using voltage source inverters, inverters (71) to (75) are required depending on the number of elevators, but one converter (4) is installed next to each other. Moreover, since part or all of the power consumption of other elevators can be supplied with regenerated power, the power consumption as a whole is reduced. Furthermore, when regenerative power is generated, contact (19a)
, (19b), (20a), and (20b), power can be returned to the power source (1), further reducing power consumption.

As explained above, in this invention, when the AC motor of the elevator is running, the converter of the voltage-type inverter device for driving the motor is connected to the inverter, and during regenerative braking, this is switched to the opposite polarity. can be used as a regenerative inverter, power can be regenerated to the power source without providing a dedicated regenerative inverter, and the device can be constructed at low cost.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a conventional AC elevator drive device, FIG. 2 is a block diagram showing an embodiment of an AC elevator drive device according to the present invention, and FIG. 3 is a block diagram showing another embodiment of the present invention. FIG. (1)... Three-phase AC power supply, (2)... Conversion device, (
4)...Converter, (7)...Inverter, (8)...
...Three-phase induction motor, (11)...Cage, (19a),
(19b)... Operating electromagnetic contactor contact, (20a)
, (20b)...Switching magnetic contactor contact, (2])
...Switching device Note that the same or equivalent parts in the figures are indicated by the same reference numerals. Agent Makoto Kuzuno (1 other person) Figure 3 Procedural amendment (voluntary) Commissioner of the Japan Patent Office 1, Indication of case Relationship to patent application No. 56-162931 Patent applicant address 2 Marunouchi, Chiyoda-ku, Tokyo Chogetsu 2-3 Name (601,) Mitsubishi Electric Corporation Representative Hitoshi Katayama 4, Agent address 2-2-3-5 Marunouchi, Chiyoda-ku, Tokyo 1% group of specifications subject to amendment Column 6 for detailed explanation of the invention
The statement of contents of the amendment is amended as follows. (2)

Claims (1)

[Claims] A converter rectifies a commercial AC power source into DC power, an inverter converts the DC power into variable frequency AC power, and the AC motor is driven by the converted AC power to operate the car. A driving device for an AC elevator, comprising a switching contact that connects the converter to the inverter when the electric motor is moving and switches the connection between the converter and the inverter to reverse polarity when the electric motor is in regenerative braking.