JPS6319429B2 - - Google Patents

Description

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

Some systems convert AC power from an AC power supply into DC using a rectifier, convert this into AC power with variable voltage and variable frequency using an inverter, and supply this to an induction motor to operate the car. In this case, lifting operation (operation in which the heavier side of the basket and counterweight is raised)
In this case, electric power is supplied to the electric motor, but the lowering load operation (operation in which the heavier side of the car and counterweight is lowered)
In this case, electric power is regenerated and flows from the electric motor to the inverter. In such a case, the DC side voltage of the inverter increases and becomes a voltage higher than the withstand voltage of the inverter or rectifier elements.
There is a possibility that the element may be destroyed. In order to prevent this, it is common to provide a regenerative inverter that returns the regenerated power to the AC power source, but this is expensive. Therefore, as a way to configure this at a low cost,
What is shown in FIG. 1 has been proposed.

In the figure, R, S, and T are three-phase AC power supplies, 1 is a circuit breaker connected to AC power supply 1, 2 is a converter consisting of a rectifier, 3 is a smoothing capacitor that smoothes the DC output of converter 2, and 4 is a smoothing capacitor. A well-known device that is connected to a capacitor 3 and pulse-width modulates a constant DC voltage to generate variable voltage/variable frequency AC power.
A PWN type inverter, 5 is a three-phase induction motor driven by the inverter 4, 6 is a brake wheel coupled to the electric motor 5, 7 is a brake wheel (not shown) provided opposite to the outer periphery of the brake wheel 6; ); 8 is a brake coil that, when energized, pulls the brake shoe 7 away from the brake wheel 6 against the force of the spring; 9 is driven by the electric motor 5; 10 is a main rope wound around the sheave 9; 11 and 12 are a cage and a counterweight connected to both ends of the main rope 10, respectively; 13 is connected to power sources R and S on the primary side; , a three-phase transformer connected to T, 14 a rectifier connected to the secondary side of the transformer 13, 15 a smoothing capacitor connected to the DC side of the rectifier 14,
16 is a start/stop device connected to the smoothing capacitor 15 to control starting and stopping of the car 11; 17 is a brake control device connected to the smoothing capacitor 15 to control the brake coil 8; 18 is a smoothing capacitor 1
A contactor control device 19 is connected to the contactor control device 5, and an operating electromagnetic contactor 19 is controlled by the contactor control device 18 and is energized when the car 11 is started and deenergized when the car 11 is stopped, and 19a to 19c are its normally open contacts. , 20 is an operating electromagnetic contactor that is deenergized at the same time as the electromagnetic contactor 19 is deenergized after the electromagnetic contactor 19 is energized, and 20a to 20c are normally open contacts thereof; 22 is a speed control device that is connected to the smoothing capacitor 15 and controls the inverter 4; 22 is a door control device that is connected to the smoothing capacitor 15 and controls the opening and closing of the car door provided in the car 11; 23 is a device that is connected between the smoothing capacitors 3 and 15; This is an inserted diode.

That is, while the car 11 is stopped, the brake shoe 7 presses the brake wheel 6 with the force of the spring. When a starting command is issued to car 11, electromagnetic contactor 19 is energized, contacts 19a to 19c are closed, and converter 2 generates a DC output. Then, the smoothing capacitor 3 is charged, and when the voltage reaches a predetermined value, the control elements (not shown) of each arm of the inverter 4 are sequentially turned on according to the operating direction, and the phase order corresponding to the operating direction is performed. Generates variable voltage/variable frequency AC power. Then,
The electromagnetic contactor 20 is energized, and the contacts 20a to 20c
is closed and AC power is supplied to the electric motor 5. At the same time, the brake coil 8 is energized so that the brake shoe 7 separates from the brake wheel 6. The electric motor 5 is now started in a direction determined by the input phase sequence, and the car 11 starts running. Then, by the operation of the speed control device 21, the output voltage and output frequency of the inverter 4 are adjusted according to the speed command signal, and the rotational speed of the electric motor 5, that is, the running speed of the car 11 is controlled. Additionally, the door control device 22
The opening and closing of the car door is controlled by the operation of the car door.

Now, when the electric motor 5 enters a regenerative operation state and the DC side voltage of the inverter 4 increases due to the regenerated power, the regenerated power flows into each of the control devices 16, 21, and 22 through the diode 23. This allows each control device 16, 21, 22 to
Since electric power is supplied to the car 11, the car 11 can continue to operate.

However, the DC side voltage of the inverter 4 is different from the output voltage of the rectifier 14, and the inverter 4
Normally, the DC side voltage is higher, and some type of level converter is required. Further, when the regenerated power is large, it is insufficient to simply flow the power to each control device 16, 21, 22. Furthermore, if the car 11 is configured to continue operating without stopping even in the event of a power outage, maintenance personnel can repair the car 11 in the elevator machine room in case of some kind of emergency.
Even if the circuit breaker 1 is shut off in an attempt to stop the car, the car 11 will continue to run, which is dangerous because it cannot be distinguished from a power outage.

This invention improves the above-mentioned problems by comparing the voltage on the AC power supply side and the voltage on the DC side of the inverter.
It is an object of the present invention to provide a control device for an AC elevator that can sufficiently process regenerative power during regenerative operation by consuming regenerative power of an electric motor according to the relative value.

An embodiment of the present invention will be described below with reference to FIGS. 2 and 3.

In the figure, 25 and 26 are resistors each having one end connected to the DC side of the inverter 4, 27 and 28 are transistors connected in series with each other and connected to the other ends of the resistors 25 and 26, respectively, and 29 and 30 are transistors, respectively. Diodes 27 and 28 are connected in parallel, 31 is a rectifier connected to AC power supplies R, S, and T, 32 is a power failure detection relay connected to the DC side of the rectifier 31, and 32a to 32d are its normally closed contacts. , 32e, 32f are normally open contacts, 33 is a rectifier connected to the circuit breaker 1, V _s1 is its output, 34 is the DC side voltage E ₁ of the inverter 4, the DC side voltage E ₂ of the rectifier 14, and the rectifier 33. The output of V _s1
is a power control device that inputs and controls transistors 27 and 28, 34a and 34b are the outputs thereof, and 35
is a voltage conversion device that calculates V _{s1 ×} K (K is a value slightly larger than the ratio of the DC side voltage E ₂ of the rectifier 14 and the DC side voltage E ₁ of the inverter 4) from the input V s1,
V _s1 ×K is set to a value slightly higher than voltage E ₂ . E _1s and E _2s are the reference voltage, respectively, and 36 is the voltage
Adder 37 calculates the deviation voltage by inputting E ₁ , E _1s , E _s1 , adder 37 calculates the deviation voltage by inputting voltage E ₂ , E _2s , V _s1 ×K, 38 and 39 respectively This is a pulse width control device comprised of a well-known integrated circuit element that generates a pulse when the input becomes negative, and the ratio of its "H" section and "L" section changes in accordance with the value of the deviation voltage. 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 supplies R, S, and T are normal, the power failure detection relay 32 is energized, the contacts 32a to 32d are open, and the contacts 32e and 32f are closed. Further, it is assumed that the circuit breaker 1 is closed.

During input operation of the electric motor 5, as explained in FIG. 1, variable voltage/variable frequency AC power is supplied from the inverter 4 to the electric motor 5, and the speed of the electric motor 5 is controlled. At this time, the DC side voltage E ₁ of the inverter 4 and the output V _s1 of the rectifier 33 are approximately equal, so the pulse width control circuit 38 does not operate and the transistor 27 does not conduct. Similarly, the output V _s1 of the voltage converter 35 is higher than the DC side voltage E ₂ of the rectifier 14
Since K is high, the pulse width control circuit 39 also does not operate and the transistor 28 does not conduct. Therefore, control power to the control devices 16, 21, 22 is supplied from the rectifier 14.

During regenerative operation of the electric motor 5, regenerative power flows into the inverter 4. As a result, the DC side voltage _E1 of the inverter 4 increases, and when it becomes higher than the output _Vs1 of the rectifier 33, the pulse width control device 38 operates,
The output 34a is generated to drive the transistor 27. Then, on/off control is performed according to the deviation voltage. Now, the regenerative power is 4-25-27-
16, 21, 22-4 circuits, control device 16,
21 and 22. When the regenerated power becomes larger and the voltage E ₁ becomes larger, and as a result, the DC side voltage E ₂ of the rectifier 14 becomes higher than V _s1 ×K, the pulse width control circuit 39 operates and outputs the output 34b. The transistor 28 is driven and turned on and off. With this, the regenerated power that could not be absorbed by the control devices 16, 21, and 22 alone is reduced to 4-25-2.
It is supplied to the resistors 25 and 26 in the circuit 7-28-26-4 and is consumed there.

Next, when the AC power supplies R, S, and T fail, the power failure detection relay 32 is deenergized and the contacts 32a to 32d
is closed, and contacts 32e and 35f are opened. Furthermore, the output V _s1 of the rectifier 33 becomes zero, and the output V _s1 ×K of the voltage converter 35 also becomes zero. Therefore, in this case, the pulse width control circuit 39 controls the voltage E ₂
operates so that the voltage becomes the reference voltage _E2s , and the output 34a
The transistor 27 is turned on and off, and the power stored in the smoothing capacitor 3 is transferred to the control device 1.
6, 21, and 22. Now, basket 11
can continue driving. In particular, in the case of a momentary power outage, normal operation can be resumed with almost no problems after power is restored. In addition, during a power outage, when performing regenerative operation in the unloading direction, voltage _E1 increases;
When E ₁ exceeds the reference voltage E _1s , the pulse width controller 38 operates and outputs an output 34b to turn the transistor 28 on and off, and the regenerated power is transferred to the resistors 25 and 2.
Consumed at 6. With this, the DC side voltage E ₁ of the inverter 4 is kept constant.

On the other hand, during normal operation, when a maintenance worker shuts off the circuit breaker 1 in an emergency, the power failure detection relay 32 is energized, so the contacts 32a to 32d are open and the contacts 32e and 32f are closed. , rectifier 3
Since the output V _s1 of No. 3 becomes zero, the pulse width control circuits 38 and 39 operate and generate outputs 34a and 34b. The transistors 27 and 28 are now conductive.
Since the smoothing capacitor 3 is discharged through the resistors 25 and 26, and the smoothing capacitor 15 is discharged through the resistor 26, the voltage applied to the control devices 16, 21, and 22 rapidly decreases, and the operating magnetic contactor contacts 20a to 2
0c is released, the brake coil 8 is deenergized, the brake is applied, and the car 11 suddenly stops. Also,
Even when performing maintenance and inspection in the machine room, if the circuit breaker 1 is shut off, the smoothing capacitors 3 and 15 will be discharged as described above, thereby preventing maintenance personnel from receiving an electric shock.

As explained above, in this invention, the output of the rectifier connected between the circuit breaker connected to the AC power supply and the contacts that close during each operation is compared with the DC side voltage of the inverter, and the voltage is determined according to the relative value. Since the regenerative power generated during regeneration of the electric motor is consumed, the regenerated power during regenerative operation can be processed according to the amount. Furthermore, the output of the rectifier is maintained at a high value even during stoppage, and there is no need to charge the smoothing capacitor every time the motor is started, thereby preventing shortening of the life of the contacts and the smoothing capacitor. Furthermore, since the output of the rectifier is reduced when the breaker is turned off, maintenance personnel can be protected from accidents such as electric shock.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a conventional AC elevator control device, FIG. 2 is a block diagram showing an embodiment of an AC elevator control device according to the present invention, and FIG. 3 is a block diagram of the power control device shown in FIG. It is a diagram. In the figure, 1...breaker, 2...converter, 3...smoothing capacitor, 4...inverter,
5... Three-phase induction motor, 8... Brake coil,
11... Car, 14... Rectifier, 15... Smoothing capacitor, 16... Start/stop device, 17... Brake control device, 18... Contactor control device, 19,
20... Operating electromagnetic contactor, 21... Speed control device, 22... Door control device, 25, 26... Resistor, 27, 28... Transistor, 33... Rectifier, 34... Power control device, 35 ...Voltage converter, 36, 37... Adder, 38, 39... Pulse width control circuit. Note that the same parts in the figures are indicated by the same reference numerals.

Claims (1)

[Claims] 1 Connect a contact that closes each time the circuit breaker is connected to an AC power source, convert the AC power supplied through this to DC using a converter, smooth it using a smoothing capacitor, and convert it to variable frequency using an inverter. is converted into alternating current power, and the converted alternating current power is used to drive an alternating current motor to operate the car, a rectifier connected between the circuit breaker and the contacts, and an output of the rectifier. a power control device that compares the voltage with the DC side voltage of the inverter and generates a signal corresponding to the relative value when the DC side voltage of the inverter becomes higher than the output voltage of the rectifier; A control device for an AC elevator, comprising a power processing device that consumes regenerative power generated during regenerative braking.