JPS5921172Y2 - AC elevator control device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of a control device for an AC elevator.

Conventionally, as a control method for an AC elevator, there is a method that uses DC braking force and applies a feedback control method.

That is, high-speed operation is performed using the high-speed electric motor, and when the vehicle reaches a deceleration position after traveling a certain distance, the high-speed electric motor is disconnected from the power source.

At the same time, a DC current is applied to the low-speed motor from a control rectifier circuit including a thyristor.

As a result, the low-speed electric motor generates a braking force to decelerate the elevator.

In this case, in order to obtain stable landing accuracy and good riding comfort, a feedback control method is generally introduced to control the thyristor of the control rectifier circuit, generate an appropriate braking force, and decelerate the elevator.

This method currently has good elevator characteristics, but
On the other hand, since the kinetic energy during the braking time is consumed as heat, the electric power is wasted and the temperature inside the elevator machine room increases.

Furthermore, as another control method for AC elevators, it is also known to switch to a low-speed electric motor and then use its regenerative braking torque to decelerate.

In this case, by connecting an AC power source to the low-speed motor, regenerative braking torque can be obtained in a speed range equal to or higher than the synchronous speed.

When the elevator decelerates to the synchronous speed of the low-speed motor,
This electric motor switches to motoring and continues running at low speed until the planned position is reached.

The AC power source is then disconnected at the predetermined position, and the electromagnetic brake is used to stop the machine.

This state is shown by the broken line in FIG.

With this method, the kinetic energy of the elevator is regenerated into the power supply during deceleration, so it can be expected to save power.

However, after decelerating to the synchronous speed of the low-speed motor,
Since the torque cannot be controlled, it is necessary to first create a low-speed driving range and then use an electromagnetic brake or the like to stop the vehicle once it has reached the planned position.

This low-speed running period is clearly a dead time (uncontrolled section) for the elevator, which increases the time required for operation and significantly reduces the transportation capacity of the elevator.

An object of the present invention is to provide a control device for an AC elevator that can eliminate low-speed running periods to improve transportation capacity, save power, and provide smooth deceleration characteristics.

The feature of the present invention is that in an AC elevator using an induction motor, during deceleration, the regeneration control torque of the motor is controlled according to the deviation between the deceleration command and the motor speed, thereby regenerating power while speeding up. It decelerates smoothly following the command, detects that the motor speed has reached a low speed at least before the equilibrium point between the regenerative braking torque and the load torque, and applies a DC braking current to the motor according to the speed command. By supplying power to the vehicle, the system is configured to follow the speed command and smoothly brake to a stop.

With this configuration, the kinetic energy of the elevator is recovered to the power source to save power, while other braking forces can be applied smoothly following the regenerative braking to stop the elevator for a long time. Driving efficiency and riding comfort can be improved by eliminating excessive low-speed running.

The present invention will be explained below with reference to embodiments shown in FIGS. 1 to 5.

FIG. 1 is a main circuit diagram of an embodiment of an AC elevator control device according to the present invention.

In the figure, numerals 1 and 2 are high-speed and low-speed induction motors (hereinafter abbreviated as IM), respectively.

These IMs are usually chosen to be 6-pole or 24-pole, and therefore have a synchronous speed ratio of 4:1.

In the figure, IMs 1 and 2 are shown as being constructed separately, but they may be constructed integrally and have two windings, and the pole number ratio is not limited to this. .

Now, these IMI and 2 are directly connected and the speed generator 3
It is connected to the sea 15 via an electromagnetic brake 4 or the like.

The sheave 5 suspends the elevator car 6 and the counterwade door via a rope in a hanging shape and drives them up and down.

The high-speed side IM1 is connected to a three-phase AC power supply 8, a main contactor 9,
They are connected via an anti-parallel thyristor 10 and a high-speed side contactor 11.

When the elevator is started and accelerated, the anti-parallel thyristor 10 is controlled to fire based on the deviation between the speed command and the actual speed, thereby controlling the speed of the elevator.

Further, the low-speed side IM 2 is connected to the three-phase AC power source 8 through the low-speed side contactor 12 .

In the figure, AC power is obtained from the output end of the anti-parallel thyristor 10, but it may also be obtained from the input end of the thyristor 10.

This low-speed side IM2 is installed mainly due to the necessity of low-speed running during maintenance operation, and the operating speed is 30 to 30.
Usually, it is selected to be about 40m/mm.

However, this low-speed side IM2 can be effectively used when decelerating the elevator.

That is, the main contactor 9 and the high-speed side contactor 11 are turned on, and the high-speed side IMI is controlled by the ignition control of the thyristor 10 to start and accelerate the elevator, and after operating at the desired speed, when the deceleration point is reached. , the high speed contactor 11 is cut off and the low speed contactor 12 is switched to the low speed contactor 12.

At this time, the speed of the elevator is usually much higher than the synchronous speed of the low speed side IM2, and the low speed side IM2 can generate regenerative braking torque to decelerate the elevator.

Furthermore, by controlling the firing of the anti-parallel thyristor 10 as necessary, the braking torque can be adjusted, and therefore the speed of the elevator can be controlled during deceleration.

In the present invention, in addition to the regenerative braking device described above, a DC braking device is added to the high-speed side IMI.

That is, the control rectifier circuit 13 is connected to the output end of the main contactor 9, and its DC side terminals are connected to arbitrary two terminals of the high speed side IMI.

The control rectifier circuit 13 includes, for example, a transformer 131
．． It consists of thyristors 132 and 133.

By controlling the firing of the thyristors 132 and 133, it is possible to generate DC braking torque on the high-speed side IMI and adjust its magnitude.

Reference numeral 14 denotes a speed command device, whose output is compared with the output of the speed generator 3 by a comparator 15, and the difference between them is detected by a phase shifter 161.
and 162.

The phase shifter 161 is provided to control the phase of the anti-parallel thyristor 10, while the phase shifter 162 is provided to control the phase of the anti-parallel thyristor 10.
This is provided to control the phase of the thyristor.

Reference numeral 17 denotes a switching point detection device, which will be described later. As an example, the speed signal of the elevator is manually input, and based on internal judgment, the phase shifter 16 is detected.
1 and 162.

FIG. 2 shows the speed command voltage given by the speed command device 14 in FIG. 1 versus time.

The illustration of the acceleration time is omitted because it is not directly related to the present invention.

Further, it is obvious that the specific circuit configuration can be obtained by an integrator or a combination of a transistor and a capacitor, and is not shown in the drawings.

FIG. 3 shows a specific example of the circuit configuration of the phase shifters 161 and 162.

In the figure, the input terminal has the output voltage e =
ep-es is given, and contacts 34 of a relay 34, which will be described later.
The capacitor 19 is charged via a.

The voltage of this capacitor 19 is applied to the base of a transistor 20, and the collector of this transistor 20 is connected through a resistor 21 to a control power supply terminal (1).

The emitter is connected to the series connection point of resistor 22 and capacitor 23.

Also, the voltage of the capacitor 23 is unijunction
Transistor (UJT).

This UJT is connected to a power source via a resistor 25 and a pulse transformer 26, and phase-controlled pulses can be taken out from the pulse transformer 26 at different times depending on the magnitude of the input voltage e.

Note that 27 is a constant voltage diode.

FIG. 4 is a diagram showing the phase angle characteristics of the phase shifters 161 and 162 with respect to the input voltage.

FIG. 5 is a circuit diagram showing an example of the switching point detection device 17 in FIG. 1, and the output voltage ep of the speed generator 3 is applied to the input terminal 28.

The operation of the transistor 29 is regulated by a resistor bridge composed of resistors 30, 31, 32, and 33, and becomes conductive when the input voltage ep applied to the resistor 33 falls below a predetermined value, thereby shorting the relay 34 and deenergizing it.

The contacts of this relay 34 are connected to the phase shifters 161 and 16 described above.
2 (Fig. 3).

However, the make contact 34a is inserted into the phase shifter 161, while the break contact is inserted into the phase shifter 162, and the two are configured to be switched.

With the above configuration, the operation of the present invention will be explained.

First, in Fig. 1, by the elevator start command,
It is assumed that the main contactor 9 and the high-speed side contactor 11 are turned on, the speed of the high-speed side IMI is controlled by the anti-parallel thyristor 10, and the elevator accelerates and reaches the deceleration command point shown in FIG.

By a floor controller (not shown),
When this deceleration command point is detected, the high speed contactor 11 is shut off and the low speed contactor 12 is turned on.

On the other hand, the output voltage es of the speed command device 14 and the speed generator 3
is compared with the output voltage ep, and the deviation e = ep - e
s is applied to two sets of phase shifters 161 and 162.

However, in FIG. 5, since the elevator is at a high enough speed, the voltage ep is also high enough that transistor 29 is non-conducting and relay 34 is energized.

Therefore, in the phase shifter 161 side circuit shown in FIG.
a is closed and generates a pulse whose phase is controlled according to the deviation.

Therefore, in FIG. 1, a firing signal is given from the phase shifter 161 to the group of anti-parallel thyristors 10, and the regenerative braking torque of the low-speed side IM2 is adjusted to reduce the elevator speed in accordance with the command, thereby reducing the kinetic energy of the elevator. is regenerated to the power source.

At this time, the other phase shifter 162 connects the break contact 34b of the relay 34 behind the input terminal 18 in FIG.
is inserted, it is in an inactive state and the control rectifier circuit 13 does not operate.

This state is a state in which the torque curve THM of the high speed side IMI has moved to the torque curve TLM of the low speed side IM2 in the IM full torque characteristic diagram shown in FIG.

For example, if the rated load is being loaded and the load torque is T1-, the load torque converted to the motor shaft is T1-, then the state has shifted from point a to TLM2.

When a heavy load increases, the deviation e-e is
p-eS becomes relatively small, and the conduction angle θ of the thyristor shown in FIG. 4 is controlled small.

Therefore, the regeneration control torque of the low speed side IM2 in FIG. 6 is relatively small like TLM2.

Of course, the magnitude of the braking torque is continuously adjusted by the momentary changes in the deviation e, but for the sake of simplicity, the elevator is decelerated along the torque curve TLM2, and the slip S.

Consider the case where the speed becomes .

In this embodiment, the switching point detection device 17 detects the above-mentioned speed S.

is detected and the phase shifter 161 is switched to phase shifter 162.

That is, in FIG. The voltage corresponding to eS
o, the bias voltage Eb applied to the base of the transistor 29 is equal to the operating voltage (base-emitter voltage) Vbe of the transistor, Eb = seo
Since the relationship CfF is selected to be +Vbe, the elevator speed decreases and the output voltage ep of the speed generator 3 becomes equal to the slip S.

When the voltage decreases to the voltage eSo corresponding to the transistor 29
conducts, and the relay 34 is deenergized.

Therefore, in FIG. 3, the circuit of phase shifter 161 is
The circuit of the phase shifter 162 (not shown) becomes inoperative when the break contact 34a is opened, while the circuit of the phase shifter 162 (not shown) starts operating when the break contact 34b is closed.

Therefore, in FIG. 1, the antiparallel thyristor 10 that was controlling the regenerative braking torque of the low speed side IM2 becomes inoperable.
On the other hand, the control rectifier circuit 13 that generates DC braking torque on the high-speed side IMI and controls its magnitude starts operating.

In this case, like the regenerative braking torque, the DC braking torque is also controlled by feedback control according to the deviation e so that the actual speed ep matches the command es, and remains effective until the elevator completely stops.

Therefore, as shown in FIG. 6, the slip S occurs.

At a speed below , the motor is decelerated and stopped by the DC braking torque TDB shown by the broken line instead of the regenerative torque TLM.

By the way, the above switching from regenerative braking to DC braking is as follows:
If it is not smooth, the ride quality of the elevator will be impaired.

In this embodiment, smooth switching is possible due to the characteristics of the phase shifter shown in FIG.

That is, when contact 34a is opened, transistor 2
Capacitor 19 is installed to prevent the base voltage of 0 from dropping suddenly.
is provided.

Therefore, the voltage e before contact 34a is opened = ep-es
The conduction angle θ gradually decreases due to the discharge characteristics of the capacitor 19 charged to
It gradually decreases like N.

On the other hand, in the circuit of the phase shifter 162, the contact 34b is closed to start operation, but the capacitor 19
The voltage does not suddenly become the input voltage e, but the conduction angle θ is gradually increased depending on its charging characteristics.

Therefore, the DC braking torque TD8 is also S in Fig. 7. → Gradually increase as shown in C.

Since the sum of these torques acts on the elevator, l
) -+C, a smooth braking torque transition occurs.

In this way, when the regenerative braking is used when the elevator is running at relatively high speeds and the DC braking is used when the elevator is running at low speeds, the following effects can be expected.

That is, (1) the kinetic energy of the elevator system at high speeds can be regenerated into a power source, resulting in power savings.

(2) As is clear from FIG. 6, regenerative braking torque disappears in the reduction region, but by supplementing this with DC braking, braking torque can be applied effectively from high speed to stop.

(3) As shown in Figure 8, regenerative braking torque is large in the high speed range, and IM DC braking torque is usually large in the relatively low speed range. , large braking torque can be obtained over the entire range.

(4) Since it is possible to perform feedback control over the entire range, as shown in Figure 9, it is possible to decelerate and stop in a linear manner as shown by the solid line, compared to the conventional regenerative braking method shown by the broken line. Therefore, the deceleration time t1 can be shortened and the transportation capacity of the elevator can be improved.

(5) According to the above, continuous speed characteristics without terraces can be obtained, and the ride comfort of the elevator is improved.

(6) If the regeneration and DC braking torques are gradually decreased and increased, respectively, as shown in FIG. 7, the transition from regeneration to DC braking can be performed smoothly, and the riding comfort of the elevator will not be impaired.

FIG. 10 shows still another embodiment of the present invention, in which a one-winding two-speed electric motor is used as the IM.

During start-up acceleration, the winding terminal U is
2. When a three-phase alternating current is applied between V2 and W2, it becomes, for example, a four-pole IM with a double star 2Y connection.

On the other hand, during deceleration, the high-speed side contactor 11 and the short-circuit contactor 3
5, open the low speed side contactor 12, and connect the winding terminal U1.
．． ■If three-phase AC is applied between 1 and W1, the telter (J
) The connection is, for example, an 8-pole IM.

Therefore, the synchronous speed at the time of delta connection is half the speed at the time of double star, and regenerative braking is possible.

In this case, as in the previous embodiment, the thyristor 10
The regenerative braking torque is controlled by

When the elevator decelerates and detects the switching point, thyristor 1
0 or open the contactor 12,
The control rectifier circuit 13 is driven.

This DC output voltage is applied between terminals U1 and W2 to obtain a strong DC braking torque.

In this case as well, the thyristors 132, 133
This controls the braking torque.

FIG. 11 shows still another embodiment, in which the DC braking circuit in FIG. 10 is improved.

That is, by igniting only the thyristors 101 and 103 in the anti-parallel thyristor 10, a DC current is caused to flow through two paths: power terminal S → contactor 1 21 and terminal S → contactor 1 and 29 , and DC braking is performed. It is designed to apply .

Furthermore, if left as is, the direct current is half-wave rectified, resulting in large pulsations, weak braking torque, and noise.

To prevent this, flywheel thyristors 36 and 37 are connected between terminals W1 and Ul and between terminals 1 and U1, respectively.

Therefore, during DC braking, the black-painted thyristor 101.
103.36 and 37 are used.

Further, these thyristors can control the braking torque not only by applying a gate signal, but also by controlling the phase as necessary.

Therefore, the entire thyristor 10 is controlled to perform regenerative braking control, and as the speed of the elevator decreases, the firing angles of the thyristors 102 and 104 are reduced, and the thyristor 101
, 103 can be increased to automatically shift to DC braking.

Furthermore, even in the case of over-deceleration, the thyristors 102 and 104
Motoring is also possible by restarting the ignition.

Other points can be controlled in the same manner as in FIG.

In FIGS. 10 and 11 above, the case where the high-speed side IM1 and the low-speed side IM2 are constituted by -winding two-speed IMs has been explained, but if the configuration of FIG. 1 is adopted and the low-speed side IM2 itself is It can also be a single winding two speed IM.

In this configuration, if regenerative braking is applied using the multi-pole winding of the low speed side IM2, the synchronous speed can be significantly lowered, so that it can be applied even to the considerably low speed range of the elevator. Regenerative braking becomes possible and the power saving effect becomes greater.

One circuit side for detecting the switching point is shown in FIG.
It is shown in FIG.

In FIG. 12, the speed of the elevator and the load are matched by a differential amplifier, but the following settings are required for both detected values.

That is, the voltage at the connection point divided by the resistor 48.49 by the voltage generated by the speed generator 3 at the rotational speed of the slide Sl in FIG. 6 is e.

Set it so that On the other hand, the output voltage of the load detection device is also set to produce a voltage C8 at the connection point of the resistors 50 and 51 at full load.

Considering the case of a full load increase, if the base voltage of the transistor 52 is at the voltage eo and the vehicle is operating at such high speed that the effect of regenerative braking is sufficiently exerted, the speed detection voltage is e.

bigger. Therefore, transistor 53 is on and transistor 52 is off.

Therefore, relay 54 is energized.

When the elevator decelerated by regenerative braking reaches a speed corresponding to the slip Sl in FIG. 6, with the above settings,
The voltage applied to the base of the transistor 53 by speed detection is e.

becomes. Therefore, if the elevator speed decreases any further, transistor 53 is turned off and transistor 52 is turned on.

As a result, the relay 54 is short-circuited and deenergized, so that the switching point can be detected by turning on and off the relay 54.

On the other hand, in the case of no-load rise or full-load fall, the 6th
When the elevator speed is at the point of slip S3 in the figure, the detected load value and the detected speed value are set to match in FIG. 12.

This makes it possible to detect the range S1→S2→S3 in FIG. 6 under any conditions.

Figure 13 shows the first load detection voltage that is switched for each rise and fall.
FIG. 2 is a circuit diagram for supplying to FIG.

That is, even if the load in the elevator car is detected by a weighing device or the like, the load torque applied to the motor shaft will be in the opposite direction in the vertical direction.

In the figure, the output of a load detection device such as a weighing device is connected between terminals a and l).

This detected value is amplified by a transistor 55, and its output is attached to the emitter resistor 57 through a contact 56 during upward operation, and taken out from the lower end of the collector resistor 59 through contact 58 during downward operation.

These output terminals c and d are connected to the load detection voltage terminal shown in FIG.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of an embodiment of an AC elevator control device according to the present invention, Fig. 2 is a diagram showing a speed command during deceleration, Fig. 3 is a circuit diagram of an embodiment of a phase shifter, and Fig. 4 is a diagram showing a speed command during deceleration. Its phase angle characteristic diagram, Fig. 5 is a circuit diagram of an embodiment of a switching point detection device from regenerative braking to other braking, and Figs. 6, 7, and 8 are illustrations for explaining the present invention. Torque characteristic diagram, Figure 9 is an elevator speed characteristic diagram, Figures 10 and 11 are main circuit configuration diagrams of other embodiments of the present invention, Figures 12 and 13.
The figure is a circuit diagram of another embodiment of the switching point detection device. 1...High-speed induction motor, 2...Low-speed induction motor, 3...Speed generator, 4...
...Electromagnetic brake, 5... Sheave, 6...
...Elevator cage, 7...Counterweight, 8...3-phase AC power supply, 9...
Main contactor, 10... Anti-parallel thyristor, 11.
...High-speed side contactor, 12...Low-speed side contactor, 13... Control rectifier circuit, 14...
Speed command device, 15... Comparator, 16...
...Phase shifter, 17...Switching point detector, 35...
...Short-circuit contactor, 36°37...Flywheel Cynostar.

Claims (1)

[Scope of utility model registration request] In an AC elevator that includes an induction motor for driving the elevator, a device that generates a deceleration command that gradually decreases toward a stop point, and a device that detects the speed of the motor, the difference between the deceleration command and the motor speed during deceleration is determined. a regenerative braking control device that controls regenerative braking torque of the electric motor according to the deviation;
Switching point detection means receives the output of the speed detection device and detects when the speed has reached a low speed at least before the equilibrium point between the regeneration control torque and the load torque, and the switching point detection means responds to the detection means and follows the deceleration command. and a device for feeding a DC braking current to the electric power source.