JPS6128588B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a device for controlling the speed of an elevator using a DC motor.

With the recent development of semiconductor devices, elevator speed control systems have replaced the Ward Leonard system.
The stationary Leonard method came into use.
Among these, there is a method called the field-controlled static Leonard method, in which the armature current of the hoisting motor is kept constant and the field current is controlled to obtain the required torque. FIG. 1 shows an example of the characteristics of the above system, in which V shows the speed, Ia shows the armature current, and If shows the field current.

By the way, the advantage of the stationary Leonard system over the Ward Leonard system is its high efficiency, that is, its low power consumption. but,
In the system shown in FIG. 1, even when the required torque is zero, a large current flows through the armature, resulting in wasteful heat generation.

The present invention aims to improve the above-mentioned drawbacks and provides an elevator speed control device that allows a DC motor to be operated with minimum power consumption.

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

In Figure 2, 1 is the elevator car, 2 is the car 1
3 is a counterweight, 4 is a main rope, 5 is a drive sheave, 6 is an armature of a DC motor that drives the sheave 5, 7 is an armature control device. unidirectional thyristor converter,
8 is an armature current detector, 9 is an ignition control circuit for controlling the converter 7, 9a is an armature current command signal input terminal, 10 is an externally excited field of the DC motor, and 11 is a bidirectional thyristor converter for field control. , 12 is a field current detector, 13 is an ignition control circuit for controlling the converter 11,
14 is a speedometer generator driven by the armature 6 and emits a speed signal 14a; 15 is a speed command signal generated from a predetermined acceleration command signal; 16 is a differentiation circuit; 16a is its output, which is equal to the above acceleration command signal. . 17 is an adder; 18 is a torque command generation circuit comprising an adder and generating a torque command signal 18a;
19 and 20 are nonlinear arithmetic circuits, 21 and 22 are output limiting circuits, 21a is a field current command signal, and 22a
is the armature current command signal.

Next, the operation of this embodiment will be explained.

The speed command signal 15 and the speed signal 14a are sent to the adder 1.
7, and the deviation signal is input to the torque command generation circuit 18. Output signal 1 of differentiator circuit 16
6a and the load signal 2a which is the output of the load measuring device 2.
is added by the torque command generation circuit 18, and becomes the torque command signal 18a. This signal 18a is transmitted to nonlinear arithmetic circuits 19 and 20 and an output limiting circuit 2, which will be described later.
1 and 22 to become a field current command signal 21a and an armature current command signal 22a. The field current command signal 21a is input to the ignition control circuit 13, and since the converter 11 is controlled by the field current signal output from the current detector 12, the field current If is controlled. Further, the armature current command signal 22a is input to the ignition control circuit 9, and the converter 7 is controlled by the field current signal which is the output of the current detector 8, and the armature current Ia is controlled. As a result, the speed of the armature 6, that is, the speed of the car 1, is changed by the speed command signal 15.
Automatically controlled with high precision.

By the way, as is well known, the speed control of the elevator is torque control, and the form of the required torque T is as shown in FIG. FIG. 3 shows, for example, a case where the total load is increased, and the interval is power running operation and the interval is regenerative operation.

Now, as is well known, the torque T generated by a DC motor is T=K・Φ・Ia where K: proportionality constant Φ: field magnetic flux Ia: armature current Magnetic flux Φ is nonlinear with respect to field current If. Yes, but
According to Fro¨hlich's empirical formula, Φ=bI _f /a+I _f (a, b are constants) Therefore, the power consumption is P, P=Ia ² Ra + I ² _f R _f where, R _a : Armature resistance R _f : Field resistance From the above formula, T=K・Ia・bI _f /a+I _f 〓I _a =a+I _f /bI _f・T/K 〓P=(a+I _f /bI _f・T/K ) ² R _a +I _f ² R _fFrom this formula, if we set dP/dI _f = 0, -a(a+I _f )T ² R _a +I ⁴ _f R _f b ² K ² = 0, which is the minimum power consumption. The conditions are as follows. From the formula, if the torque is determined as _If = f ₁ (T), the field current _If is determined. Also, if I _f is determined, Ia=f ₂
The armature current Ia is determined as (T).

The nonlinear calculation circuit 19 in FIG. 2 calculates I _f =f ₁ (T) from the required torque, and the nonlinear calculation circuit 20 similarly calculates I _a =f ₂ (T). With the field current command signal 21a and armature current command signal 22a obtained in this way,
Operation is performed with minimum power consumption.

Note that it is clear that the above acceleration command signal may be used directly instead of the output 16a of the differentiating circuit 16.

In addition, although the field-switched static Leonard system has been described in the embodiment, the unidirectional thyristor converter 7 for armature control is a bidirectional type, and the bidirectional thyristor converter 11 for field control is a unidirectional type. Of course, it can also be applied to the stationary Leonard method.

As explained above, in this invention, a torque command value is calculated from an acceleration command signal and an in-cage load signal, and further calculations are made from this torque command value to generate a field current command signal and an armature current command signal that minimize power consumption. Since the power consumption of the electric motor is outputted, the power consumption of the electric motor can be reduced.

[Brief explanation of the drawing]

Figure 1 is a characteristic curve diagram of a conventional elevator, Figure 2 is a characteristic curve diagram of a conventional elevator.
The figure is a block diagram showing one embodiment of an elevator speed control device according to the present invention, and FIG. 3 is a diagram showing the required torque form of the electric motor shown in FIG. 2. 1... Elevator car, 2... Load measuring device, 6
... Armature of DC motor, 7... Unidirectional thyristor converter for armature control, 8... Armature current detector, 9...
Ignition control circuit, 10... DC motor externally excited field magnet, 1
1... Bidirectional thyristor converter for field control, 12...
Field current detector, 13...Ignition control circuit, 15...Speed command signal, 16...Differential circuit, 17...Adder, 1
8... Torque command generation circuit, 19, 20... Nonlinear calculation circuit. Note that the same parts in the figures are indicated by the same reference numerals.

Claims (1)

[Claims] 1. A DC motor for driving the car, a speed command generation circuit that generates a speed command signal for operating the DC motor at a predetermined acceleration, a load measuring device that generates a load signal corresponding to the load in the car, and the speed command signal. A torque command generation circuit calculates a torque command signal from the differential value of and the load signal, and generates a field current command that minimizes the sum of power consumption due to armature resistance and field resistance of the DC motor from the torque command signal. An elevator comprising a first calculation circuit that calculates and outputs a signal, and a second calculation circuit that calculates and outputs an armature current command signal of the electric motor from the output of the first calculation circuit and the torque command signal. Speed control device.