JPH0326680A - Elevator control device - Google Patents

Abstract

PURPOSE:To miniaturize an inverter device by controlling a converter with the voltage reference lower than the voltage reference at the time of normal operation from the second voltage reference output device, when the device is placed in a catch test. CONSTITUTION:By a voltage reference output device 4 or by the second voltage reference device 27, for a voltage reference value 4a given through a selector switch 29, DC voltage is taken out from an AC commercial power supply 1 by a converter device 2 and converted into three-phase AC power in accordance with a speed command 18a from a speed command output device 18 by an inverter device 11, and a riding cage 1 is lifted by driving a hoisting motor 13. Here for a catch test, when heavy torque operation is performed in a short time, the selector switch 29 is selected to a side of the second voltage reference output device 27, and the second reference voltage lower than the voltage reference value at the time of normal operation from the first voltage reference output device 4 is given to the converter device 2. Thus by eliminating the necessity for forming a semiconductor element of the inverter device in large size, miniaturization of the device can be attained.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to an elevator control device.

(Prior Art) Generally, in elevator control devices, a limit design is required for the capacity and motor characteristics of the control device due to cost considerations. In particular, systems in which a motor is driven using a converter using a semiconductor element do not have sufficient overload capacity.

FIG. 5 shows an example of an elevator control device using a conventional semiconductor converter. In the figure, 1 is an AC commercial power source, and this AC commercial power source 1 is a power supply side converter device 2 for AC-to-DC conversion. is connected to via reactor 3.

This converter device 2 performs pulse width control (
A power supply that generates a PWM (PWM) switching output
It performs a switching operation upon receiving the switching output 5a of the control device 5, and is controlled to convert it into a DC voltage corresponding to the set value 4a and output it.

The DC output voltage of the converter M2 is detected by a DC voltage detector 6, and its detection output 6a and the above set value 4a are input to a power supply voltage controller 7, where a deviation is calculated and output. The output 7a (deviation) of the power supply voltage controller 7 is compared with the output 8a of the power supply current detector 8, the power supply current controller calculates the deviation, and according to the output 9a, the power supply PWM control device 5 Each element is driven and controlled to output the power supply voltage set by the voltage reference output device 4.

The current output converted and outputted by the converter device 2 is smoothed by a capacitor 10 and then inputted to an inverter device 11 for the motor, where it is converted into three-phase alternating current, and then passed through a reactor 12 to a hoisting motor 13. is given to drive this.

As a result, the main sheave 14 is rotationally driven, and the elevator car 15 is operated. In addition, 16 is a deflection sheep,
17 is a counterweight.

The control of the inverter device 11 described above is performed by the converter device 2
A speed command output device 1 that gives a speed command reference in the same way as
It is controlled to follow the output 18a of 8. however,
Unlike the converter device 2 on the power supply side, the elevator car 15
It is necessary to add the load signal 19a output from one of the load detectors to make a correction corresponding to the load. That is,
The output 19a and the output 20a of the speed detector 20 that detects the speed of the elevator enter the motor speed controller 21, where the deviation between the two is calculated and the load signal 19a is added to the output 21a. This is done in a weight signal adder 22.

Then, this addition output 22a and the output 23a of the current detector 23 that detects the current of the hoisting motor 13 are input to the motor current controller 24, the deviation thereof is calculated, and the output 24
a is input to the motor PWM controller 25, where a switching control signal 2 with a pulse width corresponding to the input 24a is input.
5a is generated, each element of the inverter device 11 is driven by this switching control signal 25a, and motor drive control that follows the speed command value 18a of the speed command output device 18 is performed.

(Problem to be Solved by the Invention) Generally speaking, in addition to normal operation, in elevators, the safety link mechanism, which is one of the elevator safety devices, operates when the speed of the elevator reaches a specified value or higher in the event of a lobe breakage, etc. A catch test is stipulated as one of the inspection items to check the operation of the car (a mechanism that forcibly holds the car stationary using friction between the device and the rail).

An example of this inspection method is to first stop the elevator, forcibly operate the governor switch that detects the acceleration of the elevator, and operate the elevator at low speed in the direction in which the safety link mechanism operates. This is a method of confirming that the mechanism operates safely and that the sheaves and lobes connected to the motor slip after the car has stopped.

In this inspection method, the control device requires a very large torque to overcome the traction force applied to the sheave and cause further slip when the electric motor is stopped.

In the induction motor control device, the slip frequency is used to generate torque when the motor is stopped.
The slip frequency is very low compared to the frequency during normal elevator operation, and in order to generate large torque, a large current must be controlled.

However, in a high-power semiconductor element such as a G-TR, internal loss increases the most when controlling a large current at a low frequency, and this may lead to instantaneous damage.

Therefore, it is necessary for the inverter device for elevators to have the ability to tolerate the above-mentioned catch test.
There was a problem that the device became larger than necessary.

In addition, in order to solve this problem, for example,
As proposed in Japanese Patent No. 56275, a method has been proposed in which the magnetic flux component current of the induction motor is increased by vector control calculation, thereby increasing the amount of torque generated relative to the current value.

However, even with this method, there are the following problems.

The loss when G-TR is used in switching operation is G
- It can be obtained from waveform observation of the collector current Ic and the collector-emick voltage Vce of the TR.
It has been shown that when [Hz] is used, the following approximation can be made. FIG. 6 shows the IC and VCE waveforms of this example and the loss waveforms converted therefrom.

Saturation loss Psat =kIcVce(sat)・
-(1) Turn-on loss 1 Pon= tr Ic Vcf' -(2)
5 Turn-off loss Poff' = (A1 t 1 + A2 t 2 )
Ic Vcf'...(3) Here, base loss Pb = k I b Vbe (sat) =
・《4) Off-state loss Pd = (1 − k )jeer Vc ・・l
5) Total loss Pt = Psat +Pon+Pof'f' +Pb
+Pd...《6》 In the above equation (6), Pb and Pd are sufficiently small values compared to the others and can be ignored in practical terms. Therefore, the total loss pt is: Pt = Psat + Pon + Poff' -- (
6) -.

Therefore, it can be seen that the main losses of a transistor are determined by the loss P sat when the transistor is on, the turn-on loss P on when switching is on, and the turn-off loss Poff when switching is off. If we look at these three elements, all of them have a collector current Ic
Contains.

However, since motor torque has a proportional relationship with current, it is unavoidable that Ic increases when the torque is heavy, and in the conventional method, G-
There was a problem that damage occurred when the maximum rating of the TR element was exceeded.

This invention was made in view of these conventional problems, and by adding a device that increases the current withstand capacity of the inverter during short-term heavy torque operation, it is possible to carry out catch tests without increasing the size of the inverter. An object of the present invention is to provide an elevator control device that can perform the following operations.

[Structure of the Invention] (Means for Solving the Problems) The elevator control device of the present invention is composed of an induction motor for driving an elevator, a converter having a power regeneration function for controlling the induction motor, a DC smoothing capacitor, and an inverter. a voltage type inverter control device, a first DC voltage command circuit that commands the inverter DC voltage value during normal operation, and a second DC voltage command circuit that commands an inverter DC voltage value lower than the command value of the first DC voltage command circuit. and a second DC voltage command circuit that transfers the inverter DC voltage command value from the first DC voltage command circuit during short-time heavy torque operation of the elevator.
A circuit for switching to the command value of the DC voltage command circuit.

(Function) In the elevator control device of the present invention, during normal operation, the first DC voltage command value necessary for normal operation is given from the first DC voltage command circuit to drive the motor.

Then, at the time of a catch command, by switching to the second DC voltage command circuit, a second DC voltage command value lower than the first DC voltage command value is given to the voltage-type inverter control device, and the total loss of the transistor is expressed by the formula 《6 ), Vc is lowered to lower the loss in terms of Pon and PofT, and the direct current IC can be increased accordingly, making it possible to generate heavy torque for a short period of time.

(Example) Hereinafter, embodiments of the present invention will be explained in detail based on the drawings.

FIG. 1 shows the circuit structure of one embodiment of the present invention, and the fifth
In the conventional elevator control device shown in the figure, a second voltage reference output device 27 that outputs a voltage reference lower than that of the voltage reference output device 18 is further provided in parallel to the power supply 28 in the voltage reference output device 18. The voltage reference 4a applied to the power supply voltage controller 7 can be switched between the voltage reference output device 18 and the second voltage reference output device 27 by means of a changeover switch 29.

The other components of the elevator control device shown in FIG. 1 are the same as those of the conventional elevator control device shown in FIG. 5, and are indicated by the same reference numerals.

Next, the operation of the elevator control device having the above configuration will be explained.

Similarly to the conventional example shown in FIG. The speed command signal 1 from the speed command output device 18 is then applied to the inverter device 11 again.
8a to the three-phase AC power necessary to rotate the hoisting motor 13 at a rotational speed corresponding to
Controls the lifting and lowering operations of 5.

Here, as conditions for determining the voltage Vdc of the DC bus 30, it is necessary to satisfy the following equations (7) and (8).

Vdc≧vSxA5×k1×1/k2 ...《7》V
dc≧V■ (8) where, vs: Effective value of power supply voltage k1: Power supply voltage fluctuation rate 1/k2: Increase due to interface/sock during converter control vI1 = Motor induced voltage peak value.

Therefore, during normal elevator operation, selector switch 2 is
9 is switched to the first voltage reference output device 4 side, and the selector switch 29 is switched to the second voltage reference output device 27 side during short-time heavy torque operation for a catch test.

Assuming that the set voltage value Vdcl of the first voltage reference output device 4 is the set voltage value Vdc2 of the second voltage reference output device 27, the set voltage value Vdcl must satisfy the above equation (7) and <<8>>. However, it is noted that the rotation speed of the hoisting motor 13, which is an induction motor, is low during short-time heavy torque operation, and Vw 4k 3 N . . . {9).

This relationship of formula <9> means that the induced voltage of the hoisting motor 13 is approximately proportional to the rotation speed N, and the above (7)
If Equation (8) has a higher value during normal operation, N is sufficiently small during short-term heavy torque operation, so Equation The value becomes high, and Vdc2 can be set to a value that produces only equation (7). And if you set it like this, V
It is possible to set dcl>Vdc2.

In particular, in high-speed and ultra-high-speed elevators commonly used today, N is large, so equation (8) is higher during normal operation than equation (7), making it possible to set the reference voltage as described above. It will become.

In this way, if it becomes possible to lower the voltage reference set value Vdc during short-time heavy torque operation than during normal operation, then in equation (6)' for the total loss of the semiconductor element, equation (2),
Since Vc is included in the losses of the turn-on loss Pon and turn-off loss Poff shown in equation <3>, the losses of these terms decrease in proportion to Vdc. especially,
If VC is used with a high value, P during the total loss
This effect is particularly large because the ratio of on and port increases, and even when the switching frequency f is high, the effect is large because the two terms of equations (2) and (3) that are related to this frequency decrease. .

Therefore, the voltage reference signal 4 from the second voltage reference output device 27
By lowering Vc by giving a, it is possible to increase the direct current value Ic by that amount, and it is possible to generate heavy torque for a short time without applying a large load to the semiconductor element.

FIG. 2 shows another embodiment of the present invention, in which the operation of the governor switch or the operation of the safety link mechanism is detected in order to automatically change the voltage setting value from large to small during the catch test. The switch operates in response to the switch operation, and sets the DC bus voltage to a low value during the catch test.

That is, in FIG. 2, 31 is a governor operation switch that detects overspeed of the elevator, 32 is an operation confirmation switch of the safety link mechanism operated by the governor overspeed detection operation switch 31, and 33 is the operation confirmation switch of the safety link mechanism that is activated by the governor overspeed detection operation switch 31. A DC voltage selection command circuit inputs the switch signals of the operation switch 31 and the operation confirmation switch 32 to select and command the DC bus voltage. 34 is a voltage standard of large and small voltage based on the command from the DC voltage selection command circuit 33. The voltage reference signal 4a from the voltage reference switching output device 34 is applied to the power supply voltage controller 7 in the elevator control device shown in FIG.

FIG. 3 shows the detailed internal structure of the DC voltage selection command circuit 33 and the voltage reference switching output device 34 in this second embodiment, where the human power 31a is the operating signal from the governor operating switch 31, and 32a is the safety signal. These are switch signals from the operation confirmation switch 32 of the link mechanism, and both are signals that become "1" during operation.

The DC voltage selection command circuit 33 includes an OR circuit 331 and an inversion circuit 332, and the voltage reference switching output device 34 connects the first voltage reference output device 4 and the second voltage reference output device 27 to the power source 28.
are connected in parallel to each other, and their outputs are connected to selector switches 341.
Further, the output of the OR circuit 331 of the DC voltage selection command circuit 33 controls the changeover switch 341 on and off, and the output of the inverting circuits 3 and 32 controls the switching. It is connected to control the on/off state of the switch 342.

The operation of the above elevator control device will be explained next.

If both the governor and safety linkage are inoperative,
The switch signals 3 1 a + 3 2 a from the operation switch 31 and the operation confirmation switch 32 are both "0", the output of the OR circuit 331 is also "0", and conversely, the output of the inverting circuit 332 is 1, the changeover switch 341 is turned off, the changeover switch 342 is turned on, and the output from the reference voltage output device 4 that provides the reference voltage Vdcl during normal operation is output as the reference voltage signal 4a.

However, when the governor operates or the safety link mechanism operates and either one or both of the operation switch 31 and the operation confirmation switch 32 becomes "1", the input signal 31a. 32a becomes "1", the output of the OR circuit 331 becomes "1", and conversely, the output of the inverting circuit 332 becomes "0", and the changeover switch 341
is turned on, the changeover switch 342 is turned off, and the voltage standard Vdc2 for short-time heavy torque operation during the catch test is turned on.
is now outputted from the second voltage reference output device 27 as the reference voltage signal 4a.

In this way, during the catch test, the operation of the governor or the safety link mechanism can be detected and the DC voltage reference value for short-term heavy torque operation can be automatically selected and output.

FIG. 4 shows still another embodiment of the present invention. In order to automatically change to heavy torque operation for a short time during the catch test, the DC voltage path selection command circuit 33 shown in FIG. Input the inspection operation switch signal 35a to input the inspection operation switch signal 35a, which is another manual condition at the time, and turn it on.
The output of the R circuit 331 is also input to the AND circuit 333, and the output of the AND circuit 333 or the AND
The output from the circuit 333 is inverted by the inverting circuit 332, and the changeover switch 3 of the voltage reference switching output device 34 is activated.
41 and 342 are controlled to turn on and off.

In this embodiment, the inspection operation switch is turned on,
When the inspection operation switch signal 35a is input manually and the governor switch signal 31a or the safety linkage mechanism operation detection switch signal 32a becomes "1", the DC voltage setting value is automatically changed to the voltage standard VdC2 during short-term heavy torque operation.
It is possible to switch to and output.

If this is done, it becomes possible to simulate heavy torque operation for a short period of time when entering a catch test during actual inspection operation.

[Effects of the Invention] As described above, according to the present invention, for short-term heavy torque operation during a catch test, a voltage reference lower than the voltage reference during normal operation is outputted in advance as the second voltage reference output device. A device is installed to control the converter, and when a catch test is entered, the converter is controlled by a low voltage reference from the second voltage reference output device, which reduces the DC current voltage that increases during short-term heavy torque operation. This eliminates the need to increase the size of the semiconductor elements of the inverter device in order to withstand the increased DC current due to short-term heavy torque operation, as is the case in the past, and the device can be made more compact.

[Brief explanation of drawings]

Fig. 1 is a block diagram of one embodiment of the present invention, Fig. 2 is a block diagram of another embodiment of the invention, and Fig. 3 is a DC voltage selection command circuit and voltage reference switching output device of the above embodiment. FIG. 4 is a block diagram showing a detailed circuit configuration of another embodiment of the present invention, and FIG.
FIG. 6 is a waveform diagram showing waveforms and loss waveforms during switching of a transistor as a semiconductor element of a general inverter device. 1... AC commercial power supply 2... Condenser overnight device 4... Voltage reference output device 5. ...Power supply PWM control device 6...DC voltage detector 7...Power supply voltage controller 8
...Power supply current detector 9...Power supply current controller fO
... Capacitor 11 ... Innoku Ichito device 1
3... Hoisting motor 14... Sheave 15...
Car 18...Speed command output device 19...
- Load detector 20...Speed detector 21...Motor speed controller 22...Load signal adder 25...Motor PWM control device 27...Second voltage reference output device 29...Switching switch

Claims (1)

[Claims] An induction motor for driving an elevator, a converter having a power regeneration function for controlling the same, a voltage type inverter control device comprising a DC smoothing capacitor and an inverter, and a first DC voltage source that commands the inverter DC voltage value during normal operation. a voltage command circuit; and a second DC voltage command circuit that commands an inverter DC voltage value lower than the command value of the first DC voltage command circuit.
and a circuit for switching the inverter DC voltage command value from the first DC voltage command circuit to the command value of the second DC voltage command circuit during short-time heavy torque operation of the elevator. Characteristic elevator control device.