JPH10120315A - Power control unit for dc elevator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a DC elevator power control unit capable of preventing the occurrence of a car vibration. and improving the landing accuracy thereof by restraining a current skip at the time of changing over a power converter. SOLUTION: A DC control unit 12 receives a time integrated signal through an integration circuit 15 regarding a difference between an armature current instruction signal IO from a speed control circuit 11 and a feedback current signal IFB detected with a polarity detection circuit 13, a polarity reversal detection signal for the armature current instruction signal IO detected with the polarity detection circuit 13, and a zero detection signal outputted when the feedback current signal IFB detected with a zero detection circuit 14 reaches the vicinity of zero. In addition, transistor drive signals 12a and 12b are outputted to a current skip inhibit circuit 16 as well as a selector circuit 17, when both of the polarity reversal detection signal and the zero detection signal are received, and charge current is fed from the current skip inhibit circuit 16 to the integration circuit 15 over the prescribed time. At the same time, the integrated value of a difference between the armature current instruction signal IO and the feedback current signal IFB is varied by the prescribed value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of power control of a DC elevator driven by a DC motor supplied from two sets of forward and reverse power converters for converting AC power into DC power. It is characterized by a technique for suppressing a jump phenomenon of an armature current which occurs at the time of switching operation of two sets of power converters.

[0002]

2. Description of the Related Art In elevators using a DC motor, a non-circulating current type reversible stationary Leonard type control device using two sets of thyristors has been proposed and actually commercialized. In the control device of this system, the connection of the thyristor group is switched at the time of switching between the power running operation and the regenerative operation of the DC motor, so that no current flows through the armature during that time, and a disconnection time of generally 50 to 300 ms occurs, or immediately after the switching. Of the DC motor due to the jump of the armature current. There is a problem that the torque pulsation of the DC motor is transmitted to the elevator car as vibrations, giving a passenger discomfort.

Therefore, various devices for overcoming such problems have been conventionally proposed and proposed. For example, Japanese Patent Application Laid-Open No. 51-27252 discloses an invention that shortens the armature current interruption time by changing the gain of an amplifier that outputs a thyristor control signal when a thyristor group is switched. JP-A-54-340 discloses that 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 a larger value than before, and after a lapse of a predetermined time, the gain is returned to the original value. The inventions that prevent the car of the elevator from vibrating by doing so are disclosed.

In Japanese Patent Application Laid-Open No. 53-23454, the polarity of an armature current is stored, and when the armature current becomes zero in a state where the vehicle is not traveling at a constant speed, the polarity is stored beforehand. Japanese Patent Application Laid-Open No. 53-121349 discloses an invention in which a bias voltage having a polarity opposite to the current polarity is added to a control signal for a thyristor group to rapidly change the voltage polarity of the control signal to shorten the current switching time of the thyristor group. If the armature current command signal is not zero when the armature current becomes zero, the armature current rise time after switching the direction of the armature current is shortened, and the armature current command signal remains zero. In each case, an invention is disclosed in which an armature current rise time command signal that outputs a normal armature current rise time is output.

[0005]

[0005] By the way, when the elevator is in a state of being balanced with a passenger-carrying car and a counterweight connected in a swinging manner, it requires a rotational force for driving when traveling at a constant speed. Therefore, the output of the armature current is controlled in a state close to zero. In addition, in order for the car to land on a certain floor with high precision, it is necessary to perform slow deceleration / stopping operation from slow low-speed traveling, and the elevator where the passenger and the counterweight are almost balanced In order to control the landing of the armature, it is necessary to perform such control as to apply a small positive / negative torque, that is, to slightly change the direction of the armature current to the positive / negative direction.

In such a case, the above-mentioned 2
In the two inventions, since the gain of the control system is changed in order to prevent the vibration of the elevator car, there is a problem in the stability of the current control, and when the armature current close to zero is controlled, the current polarity is switched. Each time, a current jump occurs, and there is a possibility that an oscillation operation may be performed. Further, in the two inventions described later, a device for preventing a current jump when controlling the armature current near zero is provided, but the direction of the armature current is finely controlled to be positive or negative. It is difficult to accurately control the landing of the elevator.

That is, in the above-mentioned prior art, the main purpose is to shorten the operation delay at the time of switching the direction of the armature current peculiar to the drive circuit using the thyristor. There has been no ingenuity for subtly controlling the vehicle in the positive and negative directions. Therefore, there is a problem that it is not possible to effectively prevent the car from vibrating or to increase the landing accuracy of the elevator. Was. The present invention has been made in view of such a problem in the prior art, and an object of the present invention is to prevent the occurrence of a vibration of a car by reliably suppressing a current jump at the time of switching a power converter, and at the same time, preventing the occurrence of a vibration. It is an object of the present invention to provide a DC elevator power control device capable of improving the landing accuracy of a car.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a DC controller which reduces a current deviation integral which is a time integral of a deviation between a measured armature current and an armature current command signal. It controls the output voltage of the power converter, and changes the value of the current deviation integral at the time of the switching operation between the powering operation and the regenerative operation of the elevator, which flows into the DC control device, to change the armature current. An armature current jump suppressing means for suppressing occurrence of a jump is provided.

For example, the armature current jump suppressing means changes the value of the current deviation integral by a predetermined value in accordance with the polarity of the armature current command signal immediately before the switching operation between the powering operation and the regenerative operation of the elevator. The switching operation of the two sets of power converters is performed when the DC control device detects that the measured armature current has become 0 or a value near 0 together with the reversal of the polarity of the armature current command signal. This is performed by a power converter switching command that issues a command for switching between powering operation and regenerative operation of the elevator.

[0010]

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 device according to the present invention, FIG. 2 is an explanatory diagram of an operation of a switching determination process F1100, and FIG. 3 is a diagram showing an integrated value of an armature current deviation and a transistor drive signal. FIG. 4 is an explanatory diagram showing a relationship between a function unit for performing the operation and the flowing armature current.
Is an operation explanatory diagram of the transistor drive signal setting / output processing F1300, FIG. 5 is an operational explanatory diagram of the armature current jump suppressing means of the present invention, and FIG. 6 is a diagram explaining the effect of the armature current jump inhibiting means.

In FIG. 1, reference numeral 1 denotes a driving AC power supply composed of three-phase AC, 2 denotes a first power converter, 3 denotes a second power converter connected in antiparallel 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 ,
4 is a zero detection circuit for the feedback current I _FB , 15 is an integration circuit, 16
Is a current jump suppressing circuit of the present invention, and 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 driving new word 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".

Naturally, 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, a transistor drive signal calculation process F12
The operation of 00 will be briefly described with reference to the function unit of FIG. The microcomputer 12 creates a phase command θ ₀ using the function 101 of the function unit and a duty ratio command γ ₀ using the function 102 based on the integrated value of the current deviation input from the integration circuit 15. Here, the duty ratio command γ ₀ is the first power converter 2
Alternatively, it sets the firing time width of the transistor constituting the second power converter 3, wherein the duty ratio command γ ₀ is the minimum, the firing time of the transistor is minimum, and the duty ratio command γ ₀ is The maximum firing time is the 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, based on 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 or the second power converter 3 and the duty ratio command γ The timing is calculated from ₀ . Accordingly, under the condition that the armature current is not intermittent, the phase 9
It can output positive and negative voltages continuously at 0 °.

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 instruction 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. Upon receiving the transistor drive command 17a or 17b,
Each transistor constituting the first power converter 2 or the second power converter 3 performs a switching operation, outputs a predetermined DC voltage, and outputs a predetermined DC voltage to the armature based on a potential difference from the DC voltage generated by the elevator DC motor 5. An electric current flows. Also, this armature current is smoothed by the DC reactor 4, and by returning this armature current as described above,
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 operating state of the elevator shifts from power running to regeneration will be described together with the operation of the current jump suppression circuit. Now, when the armature current during the 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 integrated value of the current deviation, whereas in the range below a, it becomes non-linear and the integrated value b
And the current is 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 DC motor 5 for an elevator, 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. Further, as the armature current command I ₀ is reduced, the armature current eventually becomes almost zero and the feedback current I 0
_{The FB} zero detection circuit 14 detects this 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 rising 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, this charging is completed in a set time limit 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. 3C. 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 the 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 operation state of the elevator shifts from regeneration to power running is the same, and the switching command 12
In response to the change of the logic “b” from “0” to “1”, the one-shot circuit 16 a of the current jump suppression circuit 16 switches the switching command 12 b
Is detected and a logical "0" is output.
Hereinafter, charging of the integrating capacitor 15b as described above is the same, except that a time limit is set in advance so that the integrated voltage after charging becomes, for example, b 'in FIG. 3B.

FIG. 6 shows an armature current waveform when the power converter is switched depending on the presence or absence of the above-described current jump suppression circuit 16. 3A shows a waveform in the case where the current jump suppression circuit 16 of the present invention is not provided, and FIG. 3C shows the waveform when switching to the second power converter 3 near the integrated voltage b in FIG. This indicates that a current jump represented by c in FIG. FIG. 6B is a waveform in the case where the current jump suppression circuit 16 of the present invention is provided, and shows that no current jump occurs when switching to the second power converter 3.

Further, in the region where the armature current is small as described above, there is a non-linear region where the transistor cannot follow the firing command. Therefore, when the response time of the current control system is slow, the effect of the current interruption time at the time of switching the power converter cannot be ignored. However, a self-extinguishing element such as a transistor can surely extinguish an arc by an extinguishing command, so that its switching speed is higher than that of a thyristor, and it is easy to construct a control system that is stable and has a high response speed. For this reason, when using a self-extinguishing element such as a transistor,
The current interruption time is extremely short, and its effect is negligible.

In the embodiment configured as described above, the jump of the armature current does not occur by changing the integrated voltage to a value at which the armature current does not flow when the power converter is switched. As a result, the armature current can be finely controlled, the car does not vibrate, and high landing accuracy can be obtained. Further, when the power converters are switched, since all the transistors are once extinguished, there is no simultaneous firing of the first power converter 2 and the second power converter 3, and no power supply short circuit occurs.

[0024]

As described above, according to the first aspect of the present invention, the value of the current deviation integral flowing into the DC control device during the switching operation between the power running operation and the regenerative operation of the elevator is changed. As a result, the occurrence of jumps in the armature current is suppressed, so that it is possible to prevent the occurrence of vibration of the car and to improve the landing accuracy of the car without performing complicated operations. According to the invention of claim 2, the value of the current deviation integral is changed by a predetermined value in accordance with the polarity of the armature current command signal immediately before the switching operation between the powering operation and the regenerative operation of the elevator. Therefore, high-precision traveling control according to the positive and negative operating characteristics of the semiconductor switching element constituting the power converter when a minute armature current is supplied can be achieved.

According to the third aspect of the present invention, when the polarity of the armature current command signal is inverted and when it is detected that the measured armature current has become 0 or a value near 0, the power running operation of the elevator is performed. Since the switching between the regenerative operation and the regenerative operation is commanded, it is possible to reliably detect the operating point at which the semiconductor switching element exhibits the non-linear characteristic, and to suppress the occurrence of a jump in the armature current. According to the fourth aspect of the present invention, the output of the integrating circuit for integrating the difference between the armature current command signal and the feedback current signal output from the current detector with respect to time is defined as current deviation integration, and is responsive to the output of the one-shot circuit. Since the armature current jump suppression means is constituted by the current jump suppression circuit that supplies the charging current to the integration circuit only during the closing operation period of the switch that opens and closes, the armature current jump suppression means can be constituted by a relatively simple circuit.

According to the fifth aspect of the present invention, at the time of the switching operation between the power running operation and the regenerative operation of the elevator, the power supply operation of the two sets of power converters is temporarily stopped and then the switching operation is performed. With this configuration, it is possible to reliably prevent a power supply short circuit due to simultaneous firing of two power converters.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram of a DC elevator control device according to an embodiment of the present invention.

FIG. 2 is a table showing the contents of a switching determination process;

FIG. 3 is an explanatory diagram showing a relationship between an integral value of a deviation of an armature current, a function unit for generating a drive signal of a transistor, and a flowing armature current;

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

FIG. 5 is an explanatory diagram of the operation of the armature current jump suppressing means.

FIG. 6 is a diagram for explaining the effect of the armature current jump suppressing means.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 AC power supply for drive 2, 3 First and second power converters 4 DC reactor 5 DC motor for elevator 7 Riding car 9 Current detector 10 Speed detector 11 Speed control circuit 12 DC controller 13 Polarity detection circuit 14 Zero Detection circuit 15 Integration circuit 15a Operational amplifier 15b Integration capacitor 16 Current jump suppression circuit 16a, 16b One-shot circuit 16d, 16e Limiting resistor 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 (5)

[Claims] 1. A DC motor connected to an AC power supply, comprising a plurality of self-extinguishing semiconductor switching elements, and supplied with DC power by two sets of forward and reverse power converters for converting AC power into DC power. A speed control circuit for generating an armature current command signal for the DC motor, such that an armature current flowing through the armature is measured and an elevator driven by the DC motor has a desired speed. In a power control device for a DC elevator, comprising a DC control device for controlling an output voltage of the power converter such that a deviation between an armature current and the armature current command signal is reduced, the DC control device is measured. Controlling the output voltage of the power converter so that the current deviation integral, which is the time integral of the deviation between the armature current and the armature current command signal, is reduced. Armature current jump suppression means for changing a value of the current deviation integral at the time of a switching operation between a power running operation and a regenerative operation of an elevator, which suppresses occurrence of a jump in the armature current. A power control device for a DC elevator, comprising: 2. The armature current jump suppressing means changes the value of the current deviation integral by a predetermined value in accordance with the polarity of the armature current command signal immediately before the switching operation between the powering operation and the regenerative operation of the elevator. The power control device for a DC elevator according to claim 1, wherein 3. When the DC control device detects that the measured armature current has become 0 or a value close to 0 together with the reversal of the polarity of the armature current command signal, the DC control device performs a power running operation and a regenerative operation of the elevator. 2. A power converter switching command for commanding switching between the power converters is issued.
A power control device for a DC elevator as described in the above. 4. An integrating circuit for integrating a difference between an armature current command signal generated by a speed control circuit and a feedback current signal output by a current detector for measuring an armature current flowing through an armature of a DC motor. The armature current jump suppression means is a current jump suppression circuit that supplies a charging current to the integration circuit only during a closing operation period of a switch that opens and closes in response to an output of a one-shot circuit including a monostable multivibrator. The power control device for a DC elevator according to claim 1 or 2, wherein 5. A switching operation between a power running operation and a regenerative operation of an elevator, wherein the power supply operation of the forward and reverse power converters is temporarily stopped, and then the switching operation is performed. The power control device for a DC elevator according to claim 1.