JPS5928514B2 - DC elevator control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control system for an elevator, and particularly to a control system for an elevator that controls speed by controlling the armature current of a DC motor in one direction and controlling the field current in both positive and negative directions. Regarding.

Focusing on the startup phenomenon of an elevator, the ride comfort of the seat varies depending on the load condition of the seat and the driving direction at that time.

That is, even if the brake is released to start the electric motor and a torque command is given to the electric motor according to a predetermined driving pattern, the electric motor torque does not respond immediately due to delay elements in the control system.

Depending on the state of the load torque, phenomena such as the speed rising higher than the target speed causing a jump-out phenomenon, or once reversing and then starting to move in the normal operating direction may occur during startup.

This phenomenon is a major problem for elevators and escalators that require delicate ride comfort.

Therefore, in order to eliminate this startup shock, the following methods have been adopted.

FIG. 1 shows an example of a conventional control circuit for an elevator motor using the Ward Leonard method.

The output of the speed command generator 4 and the armature voltage of the motor 5 (
Depending on the deviation from the feedback value 11 (corresponding to the speed), the generator field control amplifier 3 is controlled to adjust the generated voltage of the generator 1 which causes current to flow through the generator field winding 2 and supplies it to the motor 5.

On the other hand, a constant current is passed through the field winding 7 of the electric motor 5.

That is, the output of the field command device 10 which outputs a constant value and the output of the field current detector 8 are connected to the motor field control amplifier 9.
A constant current control system is constructed by comparing the two at.

Therefore, the electric motor 5 rotates at a speed that follows the speed command, rotates the winding drum 12, and causes the seat 13 to travel upward and downward.

At this time, if we pay attention to the startup time when the speed command takes a small value, a weight difference will occur between the rider and the balance weight 14 depending on the load 16 of the rider 13, and an unbalanced rotational force will be applied to the winding drum 12. Therefore, the electric motor 5 cannot be started smoothly, and the passenger shaft 13 generates a shock upon starting, causing discomfort to the passengers.

Therefore, for example, in Japanese Patent Publication No. 33-3577, a load detection device 15 is installed in the passenger car 13 to detect the load 16 and give the detected amount as input to the generator field control amplifier 3 via the contact 17. The armature current is controlled to generate the motor terminal voltage according to the balanced load, and the motor torque matching the load torque is generated in advance.

In other words, this is a method in which the field current is set to a constant value at startup, and the armature current is controlled to be positive or negative.

By the way, when an elevator is driven by the Ward Leonard method using this motor generator 1, the efficiency of this motor generator, the induction motor (the prime mover that drives the generator 1 and constitutes the motor generator) when the elevator is stopped, ) losses, etc.
From the point of view of effective use of electricity, there is a disadvantage that there is a lot of waste.

Therefore, it has been proposed to adopt the stationary Leonard system, which has fewer such drawbacks.

The stationary Leonard system referred to here is a system in which the motor generator part is replaced with two sets of forward and reverse Cyrisk converters.

A circulating current control method is shown in FIG. 2 as an example of the stationary Leonard method.

A three-phase power supply 18 insulated by two sets of power transformers 19 is used to supply power to the Cyrisk devices 22 and 23, which causes positive and negative currents to flow through the DC reactors 20 and 21 to the motor 5 to maintain a constant state. Positive and negative torques are generated between the magnet and the excited field 7.

However, this system requires two sets each of DC reactors 20, 21 and power transformers 22, 23, making the circuit complex and expensive.

Furthermore, since a circulating current is passed between the forward and reverse polarity switching devices in order to improve the characteristics at the time of polarity switching, there is a problem in that this control also requires very delicate control.

FIG. 3 shows a non-circulating current control method as another method of the stationary Leonard method.

In this method, one of the positive and negative side thyrisks in the thyrisk circuit 24 must be in an operating state and the other in a non-operating state, otherwise a short circuit will result in the power supply, so it is necessary to switch the polarity. This has the disadvantage that a dead time occurs during this polarity switching, and a switching shock occurs.

As a speed control method that does not have these drawbacks, a method as shown in FIG. 4 has been proposed.

In the operation of this method, the speed command Sp from the speed command device 4 and the speed feedback signal from the speed generator 29 directly connected to the electric motor 5 are input to the preamplifier 32 as a torque command generator, and the amount of deviation is calculated. It is input to the function generators 30 and 31 as a required torque command.

The output of the function generator 30 is combined with the constant armature current command of the armature current command device 40 to obtain an armature current command, which is compared with the armature current detected by the current detector 26 to perform phase control of the silisk device 22. It is applied to phase shifter 25 to control the armature current.

The output of the function generator 31 becomes a field current command, which is compared with the field current detected by the current detector 28 to control the phase of the field control thyristor 41 in addition to the field phase shifter 27 that controls the field current. to control the field current.

The motor torque is controlled by this armature current and field current (
goods).

In the illustrated example, the preamplifier 32 includes a high gain operational amplifier 36, input resistors 34 and 35, a feedback resistor 33, and a feedback capacitor 38 to form a proportional integrator.

The characteristics of the function generators 30 and 31 are as shown in FIG.

When the required torque of the electric motor 5 is small, that is,
When the torque command is small, the function generator 30 that issues the armature current command F30 does not generate an output, but combines it with the output F40 of the armature current command device 40 to maintain a small constant value.

The function generator 31 that issues the field current command F31 generates positive and negative outputs proportional to the torque command.

Further, when the required torque is large such as when the electric motor 5 is accelerating, decelerating, or under a large load, that is, when the torque command is large, the function generator 31 that issues the field current command F31 is saturated to a constant value, Operates to achieve the rated field current.

On the other hand, the function generator 30 that generates the armature current command F30 generates an output F30 proportional to the increase in the torque command from a region where the function generator 31 is saturated.

With this configuration, it is possible to reduce the temperature rise of the armature winding 6, and since the si-risk device only requires six si-risks, the cost of this device is considerably lower than that of the stationary Leonard system. This simplifies the circuit configuration and improves reliability.

In FIG. 4, in order to reduce the temperature rise of the armature winding 6; when the required torque is small, the function generator 30 does not generate an output and the - constant current from the armature current command device 40 is Only command F40 is used and a constant armature current is used.

The smaller the constant armature current value is selected, the smaller the temperature rise in the armature winding 6 will be.

However, in this system, good starting compensation cannot be achieved by simply controlling the armature current to be positive or negative depending on the load, as is done in the conventional Ward Leonard system or stationary Leonard system.

Now, looking at the case where the unbalanced torque of the elevator is large, the constant armature current command F40 is set small, so the field magnetic flux is large, that is, it is necessary to flow a large field current If.

However, the relationship between the field current of the motor and the field magnetic flux has a characteristic as shown by the solid line Φ in FIG.

That is, since it has saturation characteristics, errors occur and it becomes difficult to generate a motor torque that matches the unbalanced torque, and good elevator starting characteristics cannot be expected.

The present invention aims to provide a control system that does not cause a starting shock during startup in a DC elevator equipped with a DC motor that controls the armature current in one direction and controls the field current in both positive and negative directions. purpose.

To summarize the features of the present invention, the structure is such that a large armature current flows during startup so that load compensation torque can be generated in a region where the relationship between field current and field magnetic flux is within the proportional range. It is in.

FIG. 7 shows an embodiment of the present invention.

At startup, the load detection amount of the load detection device 15 is sent to the contact 17,
the amplifier 32 via a delay element 44 and a resistor 45;
Enter.

Since the feedback circuit is closed at the contact 46, the amplifier 32 operates as a proportional amplifier consisting of a resistor 47 and a resistor 33, and generates an output proportional to the amount of load detected by the load detection device 15. given as input.

At this time, if the constant armature current command of the armature current command device 42 is small as shown by the solid line Ias1 in the figure, this control system increases the output of the function generator 31 to increase the field current. Try to obtain the field magnetic flux.

However, since the relationship between the field current and the field magnetic flux has a saturation characteristic as shown in Fig. 6, the field current l Ifo
Even if I try to compensate by flowing I, the field magnetic flux is 1Φ.

Since only 1 is generated, the magnetic flux Φ1 that should be obtained by the originally required characteristic Φ' is 1Φ1-Φ.

1 is insufficient for magnetic flux, and optimal starting compensation is difficult.

Therefore, in the present invention, when the armature command device 42
The armature current command was increased as shown by the broken line Ias2 in Figure 7, so that the relationship between field current and field magnetic flux was within the proportional range, and the configuration was configured to generate sufficient starting compensation torque. It is something.

That is, the armature current command 'I; It82 is set large so that even when the maximum starting compensation torque is required, the field current is sufficient within the range of 1 f2 to 2 f2.

By doing so, highly accurate starting characteristics can be obtained.

Even if this large armature current command Ias 2 is set to the phase shifter 25 after confirming that the door of the car is closed, it will be done in sufficient time and sufficient starting characteristics can be obtained.

This is because the armature current is negatively fed back by the armature current detector 26, and the armature current control circuit is constructed using a cyrisk device, so the response is quick.

Because of this, the armature current that is passed during the period when the motor is stopped only needs to be passed for a very short time, which is effective because the commutator of the motor is less likely to become rough.

When the armature current command decreases from Tas 2 to Ias 1, the response is quick, so the decrease occurs with a delay element (time constant element).

By doing this, the connection from startup to operation becomes smoother and the ride becomes more comfortable.

When operation starts from startup, one of the detected load amounts is also disconnected by opening the contact point 17, and the load command is sequentially decreased through the delay element 44, resulting in a transition to smooth operation.

The contact 46 of the feedback circuit of the preamplifier 32 is also opened, and the amplifier 32 becomes a proportional-integral element including a resistor 33 and an integrating capacitor 38 to form a control circuit.

. Better starting characteristics can be obtained by matching the characteristics of the delay element 44 with the proportional-integral time constant.

In this way, by flowing a constant armature current that is twice as large during startup, highly accurate startup characteristics can be obtained without increasing the temperature rise of the armature winding at all.

FIG. 8 shows an example of changes in the output Ias of the armature current command device 42 and the speed command Vs.

A start command is given to the elevator that has stopped at a desired floor,
Assuming that door closing is completed at time t1, armature current command Ias□ generates a relatively large constant voltage.

At the same time, the electromagnetic brake is excited, but there is a time delay before it is released, and it is assumed that it is released at time t2.

The speed command Vs is generated in consideration of this time delay.

When the brake is released, if an unbalanced load exists between the car and the balance weight, a load compensation command commensurate with the magnitude of the unbalanced load is given, and the field current is adjusted.

At this time, the armature current Ta is set relatively large, so even if there is a maximum unbalanced load, the field current is sufficiently within the range of 1f2 to 1f2 in Fig. 6. Load compensation torque can be generated with high accuracy.

Therefore, the elevator is accelerated to follow the increase in the speed command Vs without jumping out or reversing.

Thereafter, from time t3, the armature current command Ias itself decreases with a time constant as shown in the figure, and at time t5 it reaches a constant value
I settled on as1.

(However, the actual armature current Ta may increase according to the characteristics shown in FIG. 5 depending on the magnitude of the torque required for acceleration.

) Note that t4 is an example of the time point at which the acceleration of the speed command Vs reaches the maximum value.

[Brief explanation of the drawing]

Figure 1 is a control circuit diagram of a conventional Ward Leonard type DC elevator, Figures 2 and 3 are stationary Leonard circuit diagrams, and Figure 4 is a DC that controls the armature current in one direction and the field current in both positive and negative directions. The elevator control circuit diagram, Figure 5 is a characteristic diagram of the function generator, Figure 6 is a diagram of the relationship between field current and field magnetic flux of the motor, Figure 7 is a diagram of an embodiment of the present invention, and Figure 8 is a diagram of the relationship between field current and field magnetic flux of the motor. It is a figure explaining the operation|movement. Explanation of symbols, 4...Speed command generator, 5...
...DC motor, 6... Armature winding, 7.
...Field winding, Sp...Speed command, 12
... Winding barrel, 13 ... Cart, 14 ...
... Balance weight, 15 ... Load detector, 1
6...Load, 22...Sirisk device, 25°27...Phase shifter, 26,28...
...Current detector, 29...Speed generator, 30,
31...Function generator, 32...Preamplifier, 41...Field control sirisk, 42...
... Armature current command device, 43, 46 ...
Contact point, 44...Delay element, 45.47...
・Resistance, Iasl t Tas□... Constant armature current command.

Claims (1)

[Claims] 1. An armature current is passed in one direction to a DC motor that drives an elevator, and a field current is passed in both directions.
In a device that has a section in which the armature current is kept constant and the field current is controlled according to the speed deviation between the speed command and the actual speed, the armature current value that is kept constant before the rise of the speed command is set. A DC elevator control device comprising means for increasing the armature current value and decreasing the armature current value after the speed command rises. 2. A DC elevator control device according to claim 1, wherein the means for reducing the armature current includes a time constant element that gradually restores the armature current to a low constant value over time.