JPH10114473A - Direct current elevator controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a current skip by varying an integral value of an electric current deviation so that armature current is prevented from flowing when a power converter is switched to a power operation or to a regenerative operation. SOLUTION: In transfer from power running to regeneration, a one-shot circuit 16b detects a drop (↓) of a switching command 12b on the receipt of a change in logic of the switching command from '1' to '0', and the logic '0' is output. By means of the '0' signal, a switch SW2 in an analog circuit 16c is closed, and an optionally set voltage and a charge current decided by a limiting resistor 16e are fed to an integration circuit 15. The integration circuit 15 is constructed of an operation amplifier 15a and an integration capacitor 15b, which is charged by output current from a current skip suppressing circuit 16. This charge is finished at the set limit in the one-shot circuit 16b. In this process, the charged integral voltage is set to the value at which no armature current flows even if travel is carried out at any speed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DC elevator having two sets of forward and reverse power converters each composed of a plurality of self-extinguishing elements for converting AC power into DC power or DC power into AC power. The present invention relates to a control device, and more particularly to a DC elevator control device suitable for suppressing a jump of an armature current and reducing a non-conduction time when a power converter is switched.

[0002]

2. Description of the Related Art In an elevator control apparatus using a DC motor, a non-circulating ammeter reversible stationary Leonard system using two sets of thyristors has been proposed and commercialized.
In this method, it is necessary to switch the thyristor group at the time of switching between the power running operation and the regenerative operation of the DC motor. The jump of the child current causes torque pulsation of the DC motor and, consequently, the vibration of the elevator car, causing a problem that passengers are uncomfortable.

For this reason, for example, Japanese Patent Application Laid-Open No. 51-27252
As disclosed in Japanese Patent Application Laid-Open No. H05-340, a method of changing the gain of an amplifier that outputs a control signal of the thyristor when the thyristor group is switched to shorten the armature current interruption time, As described in the publication, when the armature current command signal becomes zero or close to zero, the gain of the acceleration control circuit of the DC motor is set to be larger than before, and after a certain period of time, A method of restoring the gain and suppressing the vibration of the elevator car has been proposed.

Further, as described in Japanese Patent Application Laid-Open No. 53-23454, for example, the polarity in which an armature current flows is stored, the vehicle is not running at a constant speed, and the flowing armature current becomes zero. Only when this occurs, a bias voltage having a polarity corresponding to the polarity of the stored armature current is applied to the control signal of the thyristor group, the polarity of the control signal of the thyristor group is rapidly changed, and the switching time of the thyristor group is reduced. As described in Japanese Patent Application Laid-Open No. 53-121349, for example, when the flowing armature current is zero and the armature current command is not zero, the direction of the armature current is switched. A method has been proposed in which a command for shortening the later armature current rise time is output, and the shortening command is not output when the armature current command is maintained at zero.

[0005]

By the way, in an elevator, when the mass of a counterweight connected in a car and a ladder-type manner and the mass of a car and passengers are balanced, the torque when traveling at a constant speed is reduced. It is not necessary, and it is necessary to control the armature current at almost zero. Furthermore, in order for the car to land on a certain floor with high accuracy, it is necessary to perform gentle deceleration / stop from an almost constant extremely low speed. It is necessary to finely control the child current in positive and negative directions.

On the other hand, Japanese Patent Application Laid-Open No. 51-27252 proposes the above.
In the method described in Japanese Unexamined Patent Application Publication No. 54-340 and the method described in Japanese Patent Application Laid-Open No. 54-340, the gain of the control
It is difficult to construct a stable control system. When the armature current is controlled near zero, a current jump occurs every time switching is performed, and in some cases, oscillation may occur.

In the method described in Japanese Patent Application Laid-Open No. 53-23454 and the method described in Japanese Patent Application Laid-Open No. 53-121349, a current jump does not occur when the above-mentioned armature current is controlled near zero. However, it is difficult to finely control the above-mentioned armature current in the positive and negative directions, and there remains a problem in the landing accuracy of the elevator.

That is, in the conventional method, the focus is on shortening the operation delay due to the use of the thyristor, and the armature current can be finely controlled in positive and negative directions. However, there is a problem that car vibration is generated or landing accuracy of the car is poor.

The present invention has been made in view of such a situation in the prior art, and has as its object to suppress a current jump at the time of switching a power converter, shorten a non-conduction time, and generate a car vibration. Another object of the present invention is to provide a DC elevator control device that can improve the landing accuracy of a car.

[0010]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to a power converter comprising two sets of forward and reverse power converters each composed of a plurality of self-extinguishing elements, connected to a driving AC power supply. An elevator DC motor is connected to the DC motor, an armature current command of the elevator DC motor is compared with an actually flowing armature current, the current deviation is integrated, and the power converter is integrated according to an integrated value of the current deviation. In a DC elevator control device that varies an output voltage, an armature current jump suppression that changes an integral value of a current deviation so that an armature current does not flow when the power converter is switched to a power running operation or a regenerative operation of the elevator. Means and a non-linear function unit for setting the output voltage of the power converter non-linearly with respect to the integrated value of the current deviation.

Further, the armature current jump suppressing means changes the integrated value of the current deviation to a predetermined value different depending on the polarity of the armature current flowing through the power converter only when the power converter is switched. It was made.

Further, the switching of the power converter is performed by a logical product of the fact that the polarity of the armature outflow command is reversed and the flowing armature current is zero or near zero.

Further, the integration of the current deviation is performed by an analog circuit, and the integrated voltage is charged to a predetermined voltage by a one-shot circuit constituted by a monostable multivibrator only when the output converter is switched. .

The above-mentioned non-linear function unit is different for each of the forward and reverse power converters.

Further, when the power converters are switched, both power converters are temporarily stopped, and after a certain period of time, the power converters are switched and operated.

As described above, according to the present invention, the electric power constituted by a plurality of self-extinguishing elements is obtained by the logical product of the reversal of the polarity of the armature current command and the fact that the flowing armature current is zero or near zero. It is determined whether the converter can be switched. When it is determined that the switching is possible, the power converter is first temporarily stopped. Next, a one-shot multi-vibrator configured by a monostable multivibrator converts the integral value of the deviation between the armature current command and the actually flowing armature current into an integral value that does not allow the armature current to flow according to the polarity of the armature current to flow. The power converter is changed by a circuit, and after a certain period of time, the power converter is switched and operated. Further, the non-linear function acts so as to reduce the interruption time of the armature current of the switching word.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a DC elevator control apparatus according to the present invention, FIG. 2 is an explanatory diagram of an operation of a switching determination process F1100, and FIG. 3 is an integrated value of an armature current deviation and driving of a transistor. FIG. 4 is an explanatory diagram showing the relationship between the nonlinear function unit of the present invention for generating a signal and the flowing armature current, and FIG. 4 shows a transistor drive signal setting / output process F13.
FIG. 5 is an operation explanatory diagram of the armature current jump suppressing means of the present invention.

In FIG. 1, reference numeral 1 denotes a driving AC power supply composed of a three-phase AC, 2 denotes a first power converter, 3 denotes a second power converter connected in anti-parallel with the first power converter 2, 4 is a DC reactor, 5 is a DC motor for an elevator, 6 is a sheave,
7 is a car, 8 is a counterweight, 9 is a current detector,
10 is a speed detector, 11 is a speed control circuit, 12 is a microcomputer, 13 is a polarity detection circuit of the armature current command I ₀ , 14 is a zero detection circuit of the feedback current I _FB , 15 is an integration circuit, and 16 is the present invention. A current jump suppressing circuit 17 is a switching circuit.

Next, the operation of the present invention will be described. now,
When raising or lowering the car 7, the speed control circuit 11 calculates a predetermined speed command, calculates the required torque from the relationship between the mass of the car 7 and the passenger and the mass of the counterweight 8, and calculates the armature current command. and it outputs the I _0. The armature current command I ₀ is compared with an armature current actually flowing through the circuit, that is, a feedback current I _FB detected by the current detector 9, and this current deviation is integrated by the integration circuit 15 and input to the microcomputer 12. I do. Further, the output of the polarity detection circuit 13 of the armature current command I ₀ and the output of the zero detection circuit 14 of the feedback current I _FB are also input to the microcomputer 12.

The microcomputer 12 includes a normal process F1000 that is started by a timer interrupt at a predetermined interval, a switching determination process F1100, and a transistor drive signal calculation process F1.
200, transistor drive signal setting / output processing F130
0 is sequentially executed. First, switching determination processing F
The operation of 1100 will be described with reference to FIG. Microcomputer 12
Is the two conditions of whether the armature current command I polarity changes and the feedback current I _{FB 0} input is substantially zero, sets a switching command. That is, when the feedback current _IFB exceeds an arbitrary value other than zero, the setting of the switching command is not changed, and the switching of the first power converter 2 and the second power converter 3 is not performed. Further, the feedback current I _FB is substantially zero, and if the polarity of the armature current command I ₀ is changed, that is, when the polarity of the armature current command I ₀ is changed from positive to negative, the setting of the switching command Is changed to logic "0", and when it changes from negative to positive, the setting of the switching command is changed to logic "1".

Of course, if the polarity of the armature current command I ₀ does not change even if the feedback current I _FB is almost zero,
Do not change the settings. Here, in the zero detection of the feedback current I _FB , the case where the feedback current I _FB is set to almost zero has been described.

Next, transistor drive signal calculation processing F12
The operation of 00 will be briefly described using the nonlinear function unit for the first power converter 2 in FIG. The microcomputer 12 uses the function 101 of the function unit to convert the phase command θ ₀ into the function 102 based on the integrated value of the current deviation input from the integration circuit 15.
Is used to create the duty ratio command γ ₀ . Here, the duty ratio command γ ₀ is for setting the ignition time width of the transistor constituting the first power converter 2, and the duty ratio command γ ₀ is minimum and the ignition time of the transistor is minimum. The duty ratio command γ ₀ is maximum and the firing time is maximum. On the other hand, the phase command θ ₀ is set in the range of 0 ° to 180 °, and is varied only in the range of the phase control in which the duty ratio command γ ₀ is the minimum, and is otherwise fixed at 0 ° or 180 °. next,
From the relationship between the power supply voltage phase of the driving AC power supply 1 and the phase command θ ₀ , the switching order of the transistors constituting the first power converter 2 and the timing thereof are calculated from the duty ratio command γ ₀ .

Thus, under the condition that the armature current is not intermittent, positive and negative voltages can be continuously output at a phase of 90 °.

FIG. 3C shows a non-linear function unit for the second power converter 3, which is different from the non-linear function unit of FIG.
The function of the phase command θ ₀ with respect to the integrated value of the current deviation is expressed as 103
In addition, the function of the duty ratio command γ ₀ is set to 104, which is the same in calculating the switching order of the transistors constituting the second power converter 3 and the timing thereof. .

The transistor drive signal setting / output processing F1300 performs various signal output processing according to the switching order, timing, and state of the switching command. The operation of the process F1300 will be described with reference to FIG. If there is no change in the switching command set in the above-mentioned process F1100, it is determined that there is no switching (F1310), and the switching order and the timing of the transistors obtained in the above-mentioned process F1200 are output (F132).
0), and the process ends. If there is a change in the setting of the switching command, it is determined that switching has been performed (F1310),
Outputs a command to extinguish all transistors immediately. further,
The changed switching command 12b is output as logic "0" or logic "1", and the process ends.

Next, in the switching circuit 17, the switching command 1
2b, the transistor drive signal 12a with logic "1"
Is output to the first power converter 2 as the transistor drive command 17a, and the logic "0" is output to the second power converter 3 as the transistor drive command 17b. In response to the transistor drive command 17a or 17b, each transistor constituting the first power converter 2 or the second output converter 3 performs a switching operation, outputs a predetermined DC voltage, and outputs a predetermined DC voltage. The armature current flows due to the potential difference from the generated DC voltage. The armature current is smoothed by the DC reactor 4, and the armature current is fed back as described above, so that the armature current is controlled with high accuracy, and thus the required torque is controlled. Further, the rotation speed of the elevator DC motor 5 is detected by the speed detector 10 and the speed is returned to the speed control circuit so as to reduce the speed deviation. The car 7 is controlled to have a high precision and a smooth ride.

Next, the detailed operation of controlling the armature current when the operation state of the elevator shifts from power running to regeneration will be described together with the operation of the outflow jump suppression circuit. Now, when the armature current during power running operation is supplied by the first power converter 2, the armature current has a characteristic shown in FIG. 3B with respect to the integrated value of the current deviation. As is clear from the figure, when the armature current is larger than the value of a, there is a linear relationship with the integral value of the current deviation, whereas in the range below a, it becomes non-linear and the first power is When the output voltage of the converter 2 and the voltage generated by the elevator DC motor 5 become equal, the current becomes zero. This is because when the current is small, the back electromotive voltage generated by the DC reactor 4 is small, and the transistor in the reverse bias state is unlikely to fire in response to the drive command. Further, this characteristic curve moves in parallel according to the speed of the elevator DC motor 5, that is, the generated voltage. Now, when moving to regenerative operation, the armature current command I ₀ is decreased, the integral value of the current deviation moves to the left in FIG. 3 (b), the reducing armature current. When the armature current command I ₀ is further reduced, the armature current eventually becomes substantially zero, and the zero detection circuit 14 for the feedback current I _FB detects it and outputs it to the microcomputer 12. Thereafter, when the polarity of the armature current command I ₀ turns negative, the polarity detection circuit 13 of the armature current command I ₀ detects this and outputs it to the microcomputer 12. As a result, the switching command is set to logic "0" in the above-described process F1100, and a command to immediately extinguish all the transistors is output in process F1300. Further, the switching command 12b is changed from logic "1" to "0" and output.

The logic "1" to "0" of the switching command 12b
In response to the change, the current jump suppression circuit 16 shown in FIG. 5 operates as follows. First, the one-shot circuit 16b detects the falling edge (↓) of the switching command 12b and outputs a logical "0".
Is output. The “0” signal causes the analog circuit 16
(c) SW2 is closed and the arbitrarily set voltage and limiting resistor 16
The charging current determined by e is supplied to the integrating circuit 15. The integrating circuit 15 includes an operational amplifier 15a and an integrating capacitor 15b.
The output current from the current jump suppression circuit 16 charges the integration capacitor 15b. Then, the charging is terminated by the setting limitation of the one-shot circuit 16b. Here, a time limit is set in advance so that the integrated voltage to be charged is, for example, d 'in FIG. 3D. That is, the integrated voltage d at which the armature current becomes zero varies depending on the voltage generated by the DC motor 5 for an elevator as described above, and has a value at which the armature current does not flow at any speed. To set.

The operation principle when the operating state of the elevator shifts from regeneration to power running is the same, and the switching command 12b
In response to the change from the logic "0" to "1", the one-shot circuit 16a of the current jump suppression circuit 16 detects the rise (↑) of the switching command 12b and outputs the logic "0". Hereinafter, charging the integration capacitor 15b as described above is the same, except that a time limit is set so that the integrated voltage after charging becomes, for example, b 'in FIG. 3B.

By the operation of the above-described current jump suppression circuit 16, no current jump occurs when the power converter is switched, regardless of the speed at which the elevator DC motor 5 is rotating.

The slope of the function 102 of the flow control 1 of the first power converter 2 in FIG. 3A and the function 104 of the flow control 3 of the second power converter 3 in FIG. , The rate of change of the duty ratio command γ _{0 in} the small armature current region can be increased, and the response time of the current control system when switching the power converter can be shortened. Thereby, the interruption time of the armature current can be reduced.

In order to speed up the response of the current control system, for example, it can be achieved by reducing the capacity of the integrating capacitor 15, but there is a concern that the stability of the control system may be deteriorated.
Further, this can be achieved by using a microcomputer having a high processing speed and a transistor having a high switching speed, but there is a problem that the cost is increased. According to the present invention, since the rate of change of the duty ratio command γ ₀ is increased only in the small armature current region by programming processing in the microcomputer, the stability of the control system can be ensured and the cost does not increase.

In the embodiment configured as described above, by changing the integral voltage to a value at which the armature current does not flow when the power converter is switched, the armature current does not jump, and the current is interrupted by the nonlinear function device. You can save time. As a result, the armature current can be finely controlled, the car does not vibrate, and high landing accuracy can be obtained.

When the power converters are switched, all the transistors are once extinguished, so that there is no simultaneous firing of the first power converter 2 and the second power converter 3 and no short circuit occurs.

[0036]

Since the present invention is configured as described above, it is possible to suppress the current jump at the time of switching the power converter, shorten the current interruption time, prevent the occurrence of car vibration, and improve the landing accuracy of the car. Can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram of an operation of a switching determination process F1100.

FIG. 3 is an explanatory diagram showing a relationship between a function unit and an armature current.

FIG. 4 is a transistor drive signal setting / output process F130.
0 is an operation explanatory diagram of FIG.

FIG. 5 is a diagram illustrating the operation of the armature current jump suppressing means.

[Explanation of symbols]

2 First power converter 3 Second power converter 5 DC motor for elevator 12 Microcomputer 13 Armature current command I ₀ polarity detection circuit 14 Feedback current I _FB zero detection circuit 15 Integration circuit 16 Armature current jump suppression circuit 17 Switching circuit

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toshiaki Kurosawa 1-6-6 Kanda Nishiki-cho, Chiyoda-ku, Tokyo, Japan Inside the Hitachi Building System Service (72) Inventor Terika Asazawa 1-6-6 Kanda Nishiki-cho, Chiyoda-ku, Tokyo, Japan Hitachi Building System Service, Ltd. (72) Inventor Shigenori Yoritori 1-6-6 Kanda Nishikicho, Chiyoda-ku, Tokyo, Japan Co., Ltd. Hitachi Building System Service (72) Inventor Hironori Kaneko 832 Horiguchi 832, Hitachinaka City, Ibaraki Prefecture Elevator Engineering Co., Ltd.

Claims (6)

[Claims] 1. A power converter comprising two sets of forward and reverse power converters each comprising a plurality of self-extinguishing elements is connected to a driving AC power supply, and a DC motor for an elevator is connected to the power converter. An armature current command and an actually flowing armature current are compared, a current deviation is integrated, and a DC elevator control device that varies an output voltage of the power converter according to an integrated value of the current deviation is provided. An armature current jump suppressing means for changing an integrated value of a current deviation so that an armature current does not flow when the power converter is switched to an operation or a regenerative operation, and the power non-linearly with respect to the integrated value of the current deviation. A DC elevator control device comprising a non-linear function unit for setting an output voltage of a converter. 2. The armature current jump suppressing means changes an integrated value of a current deviation to a predetermined value which differs according to the polarity of the armature current flowing through the power converter only when the power converter is switched. The control device for a DC elevator according to claim 1, wherein: 3. The switching of the power converter is performed by a logical product of the fact that the polarity of the armature outflow command is reversed and the flowing armature current is zero or near zero. 2. The control device for a DC elevator according to claim 1. 4. The method according to claim 1, wherein the integration of the current deviation is performed by an analog circuit, and the integrated voltage is charged to a predetermined voltage by a one-shot circuit constituted by a monostable multivibrator only when the output converter is switched. Item 3. A control device for a DC elevator according to item 1 or 2. 5. The control device for a DC elevator according to claim 1, wherein the nonlinear function unit is different for each of the forward and reverse power converters. 6. The DC elevator control device according to claim 1, wherein when the power converters are switched, both power converters are temporarily stopped, and after a certain period of time, the power converters are switched and operated.