JPS599470B2 - Elevator speed control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an elevator speed control device, and more particularly to an improvement of a DC elevator speed control device that has power saving effects and cost reduction effects.

FIG. 1 shows an example of an elevator motor control circuit based on the Ward Leonard method, which is the most commonly used method.

The output of the speed command generator 4 and the armature voltage of the motor 5 (
Based on the deviation from the feedback value 11 (corresponding to the speed), the generator field control amplifier 3 is controlled to cause a 2K current to flow through the generator field winding and adjust the voltage generated by the generator 10 to be supplied to the motor 5.

On the other hand, a constant current is passed through the field winding I of the 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 moves the car 13 upward and downward.

Also, when landing on the floor, the relative distance signal between the car and the target floor is detected by the landing device 42 and the guide plate 43, and is returned to the generator field leg amplifier via the contact 44 to reduce the landing error. .

In addition, 6 is the armature winding of the electric motor 5, 14 is a counterweight, 15 is a load detector 16 in the heel 13 is a load inside the car, and 11 is a contact point for feeding back this load signal to the generator field control amplifier. It is.

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.
If you think about it from the point of view of effective use of electricity, it has the disadvantage that there is a lot of waste.

Therefore, it has been proposed to adopt the stationary Leonard method, 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.

The thyristor device 22.23 is supplied with power from the 3-phase power supply 18 using a 3-phase power supply insulated by two sets of power transformers 19, which causes positive and negative currents to flow through the DC reactor 20.21 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 method 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 thyristor devices in order to improve the characteristics of the polarity switching mechanism, there is a problem in that very delicate control is required.

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

In this method, one of the positive side thyristor and negative side thyristor in the thyristor circuit 24 must be in an operating state and the other in an inactive state, otherwise the power supply will be short-circuited, so it is necessary to switch the polarity. Not only does this require a dead time and a switching shock during polarity switching, but there are also problems with the reliability of the control system itself.

Therefore, a system as shown in FIG. 4 was proposed as a speed control system that does not have these drawbacks of the Ward Leonard system and the stationary Leonard system.

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 deviation amount is calculated. Function generator 30 . 31.

The output of the function generator 30 is combined with the constant armature current command of the armature current command device 40 to generate an armature current command, which is detected by the current detector 26 and compared with the armature current to perform phase shifting for controlling the phase of the thyristor device 220. 25 to control the armature current.

In addition, 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, and in addition to the field phase shifter 27 that controls the field current, the field control Cyrisk 410 phase control is performed. Then, apply the field current.

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

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.

Function generator 30. The characteristics of No. 31 are as shown in FIG.

When the required torque of the electric motor 50 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, the temperature rise in the armature winding 6 can be reduced, and the thyristor device as the armature power source only needs six thyristors, so the price of this device is lower than that of the stationary Leonard system. The cost can be considerably reduced, the circuit configuration is simple, and the reliability is improved.

On the other hand, the power saving effect is greater than that of the Ward Leonard method, as is the case with the stationary Leonard method.

However, this method of controlling the field current in both positive and negative directions and the armature current in one direction (hereinafter, an elevator driven by this method will be referred to as a field-controlled elevator) has the following problems.

In other words, if the elevator speed is controlled by controlling the armature current constant and changing the field current according to the torque command, in order to obtain good transient characteristics, it is necessary to control the speed of the field time constant. It needs to be small enough to be possible.

The superiority or inferiority of the transient characteristics has a great influence on the riding comfort and floor landing performance that are used when comparing elevator performance, so when this control method is used for elevator control, the field response is 0.2. It is necessary to shorten the time to about 0.4 seconds.

On the other hand, as is widely known, the motor field time constant is as large as 1 to 2 seconds due to the influence of its inductance, which means that this control method cannot provide good elevator performance if left as is. As a solution, it has been found that it is effective to apply a voltage several times the rated excitation voltage to the field in this field-controlled elevator to equivalently speed up the response of the field.

Hereinafter, the ratio of the applied voltage to the rated excitation voltage will be referred to as the hosing ratio.

FIG. 6 shows the measurement results of landing errors due to load changes in a state where a voltage three times the rated excitation voltage is applied to the field (hosing ratio is 3).

Although the ride comfort was almost satisfactory with this level of hosing ratio, the landing error (difference between the building floor and the elevator floor) was ±20wIL, which is large enough to be used as a guideline for evaluating normal elevator performance. This is inferior to the current value of ±10R, indicating that the setting of the hosing ratio is insufficient and the voltage applied to the field is still insufficient.

Furthermore, the voltage applied to the field winding was increased to 6
FIG. 1 shows the results of suppressing landing errors due to load changes when double the voltage is applied (hosing ratio is 6).

The landing error was ±9M, which almost satisfied the required performance.However, in a field-controlled elevator that controls the elevator speed by controlling the field current in both positive and negative directions and the armature current in one direction, the required elevator performance is not achieved. In order to obtain this, it was found that it was necessary to apply a voltage considerably higher than the rated excitation voltage to the field winding to reduce the field time constant.

However, if the hosing ratio is set this high in order to obtain good performance, the thyristor used in the field circuit must be a special type with higher voltage resistance than the general-purpose type, and the motor field winding There is also the problem that a special specification product with high voltage resistance must be designed for the line, which may undermine the main advantage of the field-controlled elevator, which is that it is cheaper than the stationary Leonard system.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks of the prior art and to provide a speed control device for a DC elevator that has power saving effects and cost reduction effects.

The present invention has confirmed through experiments that the landing performance of field-controlled elevators depends on the magnitude of the hosing ratio of the field circuit, and as a means to obtain good landing performance with a low hosing ratio, The relative distance signal with the floor,
This system is characterized in that the deviation between the speed command and the car speed signal is input to a comparator that generates it.

An embodiment of the present invention is shown in FIG.

The armature current flows in one direction according to the torque command and the characteristics of the function generator 30, and the field current flows according to the torque command and the characteristics of the function generator 3.
10 flows in both positive and negative directions depending on the torque, generating electric motor torque between the two, and operating the riding heel 13 in accordance with the output of the speed command generating device 4.

After operation, the elevator slows down as it approaches the destination floor.
When landing on the floor, the contact point 44 closes and occurs depending on the relative distance between the landing device 42 installed in the car 13 and the guide plate located at the target stop floor among the guide plates 43 provided for each floor. A position command is input to a preamplifier 32, which is part of the speed controller.

On the other hand, since the speed feedback signal representing the speed of the car is also input to the preamplifier, a comparison between the two is performed in the preamplifier.

For this reason, if the elevator goes too far past the target stop floor surface, a speed command is given to bring it back, but if it falls short, a speed command is added to move it further, so the speed command is always zero. In other words, the elevator must be controlled so that it stops at the correct position.

Therefore, even if the hosing ratio is set to a small value in the conventional field ffl control elevator, accurate landing can be achieved and cost reduction is possible.

By the way, let's compare the costs when the hosing ratio is set to a necessary and sufficient value and when the present invention is used.

The price of the field control device when the hosing ratio is set to about 6 (equivalent to the former), the hosing ratio is about 3.
The rate of cost reduction of the field control device and electric motor when the present invention is used is approximately 50 times, and by adopting the present invention, the cost of the field current control device is equivalently halved (this figure is By using the present invention, the withstand voltage of the thyristor, the capacity of the power transformer, and the withstand voltage of the motor field winding can be reduced to 1/2. This was obtained as a result of comprehensive consideration of the points that would require the provision of each.

)can do.

It can be said that the cost reduction effect of the present invention is particularly great for field control elevators that are adopted for the purpose of economical efficiency.

Next, the speed control performance of the present invention will be described.

Figure 9 shows the results of measuring the landing characteristics using the circuit in Figure 8 with the field circuit hosing ratio set as low as possible within the range that actually provides good riding comfort and the field applied voltage in an insufficient state. show.

(When the hosing ratio is 3) ±20 rrr in Figure 6
The implantation error, which was m, was greatly improved to ±LM.

The reason for such a large effect is not only that the relative distance signal between the car and the destination floor is input into the preamplifier at the time of landing, but also that the preamplifier in this example is a proportional integrator. He has become a big H prisoner.

In other words, even if the relative distance command issued by the landing device 42 is extremely small, the preamplifier continues to output until the required field current or armature current is obtained.
This is because the landing position of the car can be reduced over time, regardless of the load inside the car.

In this way, according to this embodiment, the landing error can be extremely reduced.

Here, as an example of a system that controls the field current in both positive and negative directions and the armature current in one direction, as shown in Figure 5, when the torque command (deviation between the speed command and the speed feedback value) is small, the armature current is controlled to a constant value in one direction, the field current is controlled to be positive or negative according to the torque command, and when the torque command force is large, the field current is controlled to be constant to a positive or negative value, and the armature The explanation has been given using a control method in which the current is changed in one direction according to the torque command, but there is also a method in which the armature current is controlled to a constant value in one direction and only the field current is changed positive or negative according to the torque command, and an elevator Control that has sections in which the field current is controlled to be positive or negative according to the torque command, such as a method in which the armature current is increased to a certain value in one direction during acceleration or deceleration, and the field current is changed to positive or negative according to the torque command. It goes without saying that the present invention can be applied to other systems.

In addition, in the embodiment shown in FIG. 8, the contact 44 is closed after the speed command from the speed command generator 4 becomes zero, and the position control system starts operating after the car has almost stopped. Similar effects can be obtained by adopting a method in which the speed command from the speed command generator 4 is turned OFF during deceleration, the contact 44a is closed, and the control system is switched to position control during deceleration, as in the embodiment shown in Fig. 10. is obvious.

According to the present invention, landing performance can be improved at low cost in a field-controlled elevator.

[Brief explanation of drawings]

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 control circuit 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, Figures 6 and γ are diagrams showing the landing characteristics of a DC elevator that controls the armature current in one direction and the field current in both positive and negative directions. Figure 8 is a circuit diagram showing an embodiment of the present invention, Figure 9 is a diagram showing implantation characteristics when the present invention is used, and Figure 10 is a diagram showing the implantation characteristics when the present invention is used.
The figure is a circuit diagram showing another embodiment of the present invention. 4...Speed command generation device, 5...DC motor, 6.
... Armature winding, T ... Field winding, SP ... Speed command, 12 ... Winding drum, 13 ... Driving basket, 14 ... Balance weight, 15 ... Load detector , 16...Load, 22
．． 41... Cyrisk device, 25,2γ... Phase shifter, 26. 28... Current detector, 29... Velocity generator, 30.31... Function generator, 32... Preamplifier (ratio articulator), 42... Implantation device, 43... - Guidance plate, 44... contact.

Claims (1)

[Claims] 1. A DC motor for driving an elevator, an armature power supply device that supplies current in one direction to the armature of this motor, a field power supply device that supplies current in both positive and negative directions to the field of the motor, and an elevator speed command generation device a speed feedback signal generating device that represents the actual speed of the elevator; a comparator that generates a deviation signal between the speed command and the speed feedback signal; A device for controlling the magnetic power supply device, a device for controlling the armature power supply device according to the deviation signal when the deviation signal is a predetermined value or more, and a hosing ratio of the field power source is set in a range of 1 to 3. An elevator speed control device comprising: a device for inputting a signal to the comparator according to a relative distance between an elevator passenger and a floor to be landed upon landing of the elevator.