JPS58224977A - Controller for speed of elevator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for controlling the speed of an elevator motor by means of a thyristor.

BACKGROUND OF THE INVENTION Recently, electric motors of elevators have been controlled by stationary Leonard devices such as thyristors. An example of this is shown in FIG.

FIG. 1 is a diagram showing the configuration of a conventional elevator speed control device using a non-circulating current type reversible static Leonard device. In the figure, 1 is a three-phase AC power supply, 2A is a thyristor converter that supplies power when the DC motor 6 is running in the upward direction, for example, in the ascending operation of an elevator, and 2B is a thyristor converter that supplies regenerative power during the regenerative operation of the DC motor B in the upward operation of the elevator. Power supply 1
Thyristor conversion device to send to, 4 is the sheave of the hoist, 5 is the lobe, 6 is the elevator car, 7 is the counterweight, 8
9 is a current regulator; 9 is a phase shifter; 110A and 10B are switches for providing gate pulses during operation of the thyristor conversion devices 2 and 2B, respectively; 11 is a speed regulator; and 12 is a current shunt. A gate pulse is applied to the thyristor converter 2 or 2B from the phase shifter 9 at a firing angle determined according to the output of the current regulator 8 via the switches IOA and IOB, respectively, and a speed command is applied to the current. (not shown) is given to the current regulator 8. Furthermore, current feedback from the shunt 12 and speed feedback from the DC motor 3 (
(not shown) improves the performance of the control system, and the speed of the car 6 is controlled with high accuracy.

By the way, in the above configuration, when the DC motor 3 shifts from the power operation to the regenerative operation during the upward operation of the elevator, the current direction of the load is changed, so the thyristor conversion device changes from 2A to 2B by the operation of the switches IOA and 10B.
However, this switching must be performed when the load current of the DC motor 3 is zero. This means that when the load current is not zero and the components of the thyristor converter 2A are in a conductive state, when the thyristor converter 2B is fired, two thyristor converters 2A are activated.

This is because the power supply 1 is short-circuited through 2B and becomes inoperable.

Therefore, this switching is performed, for example, after the gate pulse applied to the thyristor converter 2A on the power running side is cut off with the switch 10A to stop the operation, and after a suitable amount of time has elapsed and the load current has definitely become zero, the regeneration side is switched on. Thyristor conversion device 2
A gate pulse is applied to B via switch 10B.
At this time, when the thyristor conversion device 2B starts operating, if a gate pulse is applied with an abnormal phase, an excessive rush current will flow.

In order to prevent this phenomenon, conventionally, after opening the switch IOA to cut off the gate pulse and stopping the operation of the power running side Sirisk conversion device 2A, the output of the current regulator 8, which is the phase shifter input signal, is The control delay angle is maintained at a value corresponding to the γ limit, that is, the value at which the load current of the thyristor converter 2B is least likely to flow, and then the switch 10B is closed and the regenerative side thyristor
-) The method used was to apply a gate pulse to the evening conversion device 2B to start regenerative operation.

However, in this method, the regeneration side thyristor conversion device 2B
However, it is 1100mK to 200mK before the regenerative current starts flowing.
During this time, the current regulator 8 loses its function, so the speed control function for the elevator car also stops, the amount of deviation accumulates, and the thyristor converter 2B on the regeneration side enters the control state. At this point, the current supplied to the DC motor 6 overshoots, giving a shock to the car 6 and significantly deteriorating the riding comfort. The above-mentioned phenomenon also applies to switching during descending operation of the elevator or switching from the regeneration side to the power running side.

The present invention has been made to solve the above-mentioned drawbacks.
The purpose is to provide an elevator speed control device that reduces the time required to switch the current direction, thereby smoothing changes in motor torque and improving riding comfort.

Therefore, in the present invention, when switching the current direction, the value of the phase shifter input signal at the time when the control operation is started is not set to a value equivalent to the conventional γ limit, but when the load current becomes zero and the control operation is stopped. By setting the output to correspond to the optimal phase shift calculated from the phase shifter input value, the time required for switching is shortened.

The present invention will be explained in detail below. First, the phase shifter characteristics common to the two thyristor conversion devices 2A and 2B in FIG. 1 are expressed by the following equation.

α−−x 180 +90 (dθg),,o+v Here, α is the control delay angle, and e is the phase shifter input (e−−V~→
−■ variable width), ■ is the reference voltage.

A phase shifter having such characteristics can be easily realized by using a sawtooth wave as shown in FIG. 2(b) for the power supply voltage waveform shown in FIG. 2(a).

Now, in the configuration of the younger brother 1, the thyristor conversion device 2
A is the control delay angle α corresponding to the input voltage e of the phase shifter 9,
If the current direction is switched during operation, the load current at the time when the thyristor converter 2A stops controlling is almost zero, so the peak value of the output voltage of the thyristor converter 2A is: It becomes equal to the back electromotive force 1ira of the DC motor 6. From this, the following equation holds true.

E E, M au (α1-30°)-xa, , ,
(21Here, EAC is the three-phase AC power supply voltage.On the other hand, when the back electromotive voltage of the DC motor 3 is Ea, the minimum current at the start of operation of the thyristor converter 2B that starts control becomes zero. When the control delay angle of is α2, the following equation holds true.

JE KA(au (α2-30°)-Ea,,,(3
) From equations (2) and (3), the relationship between control delay angles α1 and α2 is expressed by the following equation.

α, +α2−240°, , , (4) Control delay angle α
If the phase shifter force for , is e, then (Equation 11 and (
From equation 4), the relationship e@--V-elo, (51) holds between phase shifter human power θ, and 02. Therefore, if the relationship of equation (5) is satisfied, Switching of the current direction is performed most smoothly.An example of a circuit configuration that satisfies the relationship of equation (5) is shown in FIG.

In the figure, SW is open when the current regulator 8 is in operation, and switches 10A and 10B are opened in the process of switching the current direction.
13 is a resistor r9. A differential amplifier with a no-gain characteristic consisting of r10 and OP amplifier OP2, R1 and R2 are resistors with the same resistance value, and 14 is a phase shifter input signal which is an input signal by a hold signal SWa at the same time as the switch SW is closed. A sample and hold circuit 15 holds a value of 1, a voltage source 15, and other components that are the same as in FIG. 1 are denoted by the same reference numerals. Note that the current regulator 8 includes resistors r1 to r4 and a capacitor C! 1.OP
The amplifier opi constitutes a so-called P-knee cylinder.

With the above configuration, if we consider a case where the current direction is changed while the Cyrisk converter 2A is in operation, the switch 10A is opened and the switch SW is closed, and at the same time the hold signal SWa is used to change the current direction. The phase input power 431 is held in the sample and hold circuit 14, and its output, that is, the potential at point b, is also held at 0m. Therefore, the differential amplifier 13 is controlled by the resistors R1 and R2 and the voltage source 15 so that the current regulator 8
An input signal is applied to the switch SW via the switch SW. After a certain period of time has elapsed, the switch 10B is closed and the thyristor converter 2B starts operating. At this time, the phase shifter manual power θ, corresponds to sa in equation (6), and therefore, in equation (5). I know you will be satisfied. Further, when the switch 10B is closed, the switch SW is opened, the hold signal SWa is released, and the sample and hold circuit 14 starts sampling again. Therefore, according to this configuration, when the current direction is switched, the output voltage of the current regulator becomes the optimum value immediately after switching, so the time during which speed control is stopped is 1710 times longer than in the conventional method. It will be shortened to a certain extent.

As described above, according to the present invention, the initial setting value of the firing phase of the thyristor conversion device that newly operates when the current direction is switched can be optimally set based on equation (5). The stopping time of speed control associated with switching can be significantly shortened compared to the conventional method, there is almost no current overshoot during switching, and the shock to the car due to sudden torque changes of the electric motor is reduced, improving ride comfort. I can do it.

[Brief explanation of the drawing]

Figure 1 is a block diagram showing a conventional elevator speed control device, Figures 2 (a) and (b) are explanatory diagrams showing the characteristics of a phase shifter, and Figure 3 is an embodiment of the present invention. FIG. 2 is a block diagram showing the main parts of a speed control device for an elevator. 119. Three-phase AC power supply 2A, 2B, . . . Thyristor conversion device 600. DC motor 80, 2 current regulator 900. Phase shifters 10A, 10B, SW, switch 11, speed regulator 13, differential amplifier 141. Sample and hold circuit patent applicant Fujichik Co., Ltd., 11th phantom

Claims (1)

[Claims] The DC motor for driving the elevator is controlled by a non-circulating current type reversible stationary Leonard device to control the speed of the elevator, and when the current direction is changed, a pulse cutoff device that cuts off the gate pulse for a certain period of time, and a thyristor conversion device are used. A phase shifter input holding device that holds the input signal to the phase shifter that determines the ignition phase at the time the pulse cutoff device operates and outputs this value, and a current direction from the output signal of the phase shifter input holding device. 1. An elevator speed control device comprising a phase shifter input calculation device that calculates a phase shifter input signal corresponding to an optimal initial setting phase of a SIRISK conversion device that operates after switching.