KR101623284B1 - Elevator control device - Google Patents

Abstract

Provided is a control device for an elevator in which a circuit for detecting abnormality of a bus line DC voltage value of a two-level inverter can be miniaturized without requiring a large step-down circuit or an insulating circuit. For this purpose, a three-phase AC power source of neutral grounding type, a converter for converting a three-phase AC voltage from the three-phase AC power source into two levels of DC voltage of high and low potentials, And an inverter for converting an AC voltage into an AC voltage and driving the motor of the elevator, the control device comprising: a first and a second inverter connected in series between the high potential side and the low potential side of the two- And detecting means for detecting a ground potential of a connection portion of the second capacitor and the connection portion of the first and second capacitors as an intermediate voltage, wherein the detecting means detects an abnormality of two levels of DC voltage input to the inverter based on the detected intermediate voltage Is detected.

Description

[0001] ELEVATOR CONTROL DEVICE [0002]

The present invention relates to a control apparatus for an elevator.

Conventional elevators include a converter for converting a three-phase AC voltage supplied from a power source into a DC voltage, an inverter for converting a DC voltage into an AC voltage to drive an elevator motor, (Refer to, for example, Japanese Patent Application Laid-open No. 2001-325819), and a voltage detecting means for detecting the voltage of the condenser to determine whether the capacitor used in the main circuit of the elevator is good or bad .

In the power conversion control device in which two smoothing capacitors are connected in series between the converter and the inverter, the terminal (voltage) between both ends of the smoothing capacitor is taken out by the voltage dividing circuit, It is also known to detect the opening and shorting of a capacitor and a balance resistor (see, for example, Patent Document 2).

In addition, in a power inverter including a three-level inverter for converting power of three potentials of a low potential, an intermediate potential and a high potential converted from an AC by a converter into an AC, In order to suppress the fluctuation, a DC neutral point voltage control system for detecting the DC neutral voltage and controlling the DC neutral voltage has been conventionally known (see, for example, Patent Document 3).

Patent Document 1: JP-A-2010-265093 Patent Document 2: Japanese Patent Application Laid-Open No. 08-079963 Patent Document 3: Japanese Patent No. 4466618

However, the elevator has a self-diagnosis function that monitors whether there is no abnormality in the DC voltage value (inverter bus voltage value) input from the converter to the inverter or whether there is abnormality such as phase loss in the three- It is common to have the function.

However, as in the conventional elevator disclosed in Patent Document 1, when the bus line voltage of the inverter (of two levels) is directly detected and monitored, since a signal to be detected (monitored) is a very high voltage, Thus, there is a problem that the apparatus becomes large and expensive.

Since the digital system control circuit provided in the control device of the elevator generally operates at the same potential (same potential) as the ground potential, a circuit for detecting and monitoring the bus line voltage of the inverter, There is a large potential difference. Therefore, a long creepage distance and an insulating circuit are required between these circuits, so that the scale of the detection circuit becomes very large, which hinders miniaturization of the substrate.

The power conversion control apparatus disclosed in Patent Document 2 detects one terminal voltage of two smoothing capacitors connected in series in order to detect the open or short of the smoothing capacitor and the balance resistor. There is a problem that the abnormal monitoring and detection of the supplied three-phase alternating current is not taken into consideration at all and the abnormality can not be detected.

The power conversion apparatus disclosed in Patent Document 3 controls the DC neutral point voltage of the 3-level inverter by detecting the DC neutral voltage of the 3-level inverter, thereby detecting abnormality of the bus voltage value of the 2-level inverter or abnormal monitoring of 3-phase AC supplied from the power source There is no consideration at all for detection, and there is a problem that such an abnormality can not be detected.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the problems described above, and it is an object of the present invention to provide a two-level inverter which does not require a large step-down circuit and does not require a long creepage distance or an insulating circuit, And an elevator control device capable of detecting abnormality of three-phase alternating current supplied from a power source.

In the control apparatus for an elevator according to the present invention, a three-phase alternating-current power supply of a neutral point grounding method for supplying electric power to a main circuit of an elevator, and a two-phase alternating- Level inverter and an inverter for converting the DC voltage of the two levels from the converter to an AC voltage to drive an elevator motor, the elevator control device comprising: a converter provided between the converter and the inverter, A first capacitor and a second capacitor connected in series between a high potential side and a low potential side of the two-level DC voltage; and a first capacitor and a second capacitor connected in series between the high potential side and the low potential side of the two- And a detecting means for detecting the detected intermediate voltage as a voltage, It is configured to detect an abnormality of the direct current voltage level of the second group.

In the control apparatus for an elevator according to the present invention, it is unnecessary to provide a large-scale step-down circuit, and a long creepage distance and an insulation circuit are not required between the control system and the digital system control circuit. It is possible to achieve the effect of being able to do.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a view for explaining the overall configuration of a control apparatus for an elevator according to Embodiment 1 of the present invention. FIG.
2 is a circuit diagram showing a detection circuit included in a control apparatus for an elevator according to Embodiment 1 of the present invention.
3 is a diagram showing waveforms of respective phases of a three-phase AC power source according to Embodiment 1 of the present invention.
4 is a diagram showing the voltage to ground of the bus line (before smoothing) on the converter side according to the first embodiment of the present invention.
5 is a diagram showing the ground voltage of the bus line (after smoothing) on the inverter side according to the first embodiment of the present invention.
6 is a view for explaining an undervoltage detection operation in the detection circuit according to the first embodiment of the present invention.
7 is a view for explaining an overvoltage detection operation in the detection circuit according to the first embodiment of the present invention.
FIG. 8 is a view showing a waveform at the time of image formation in a three-phase AC power source according to Embodiment 1 of the present invention. FIG.
Fig. 9 is a view for explaining an image-forming-detecting operation in the detection circuit according to the first embodiment of the present invention. Fig.
10 is a diagram showing the configuration of a three-phase AC power source to a detection circuit of a control apparatus for an elevator according to Embodiment 2 of the present invention.
Fig. 11 is a view for explaining fluctuations occurring on the ground voltage of the bus line (after smoothing) on the inverter side at the time of regeneration according to the second embodiment of the present invention. Fig.
12 is a circuit diagram showing a detection circuit included in the elevator control apparatus according to Embodiment 3 of the present invention.
13 is a diagram exemplifying the detection target voltage waveform in the detection circuit according to the third embodiment of the present invention.
14 is a diagram showing a detection circuit portion included in the elevator control device according to Embodiment 4 of the present invention.

The present invention will be described with reference to the accompanying drawings. In the drawings, the same reference numerals denote the same or substantially equivalent parts, and redundant descriptions thereof are appropriately simplified or omitted.

Embodiment 1

Fig. 1 is a diagram for explaining the overall configuration of a control apparatus of an elevator. Fig. 2 is a circuit diagram showing a detection circuit included in a control apparatus of an elevator. Fig. 3 Fig. 4 is a diagram showing the ground voltage of the bus line (before smoothing) on the converter side, Fig. 5 is a diagram showing the ground voltage of the bus line (after smoothing) on the inverter side, 6 is a view for explaining an undervoltage detection operation in the detection circuit, FIG. 7 is a view for explaining an overvoltage detection operation in the detection circuit, FIG. 8 is a view showing a waveform at the time of image formation in a three- Fig. 9 is a view for explaining the image-forming-detecting operation in the detection circuit.

1, reference numeral 1 denotes a three-phase AC power source for supplying power to a main circuit of an elevator. As the three-phase AC power supply 1, for example, a commercial power supply on the building side where an elevator is installed is used. However, in general, when the power source is a three-phase AC power source having a phase voltage of 400 V or more, a neutral point is often grounded. Neutral point grounding is employed also in the three-phase AC power supply 1.

The power supplied by the three-phase AC power supply 1 is received by an elevator control panel provided with a control device of the elevator. The AC voltage of the received three-phase AC power source 1 is converted into a DC voltage by the converter 2. The output of the converter 2 has two levels, that is, the ground voltage is the low voltage N and the high voltage P is higher than the low voltage, and the DC voltage of the two levels is the bus voltage (on the converter side). Further, in the above description, the words " voltage " and " potential " may be used in the same meaning without distinguishing them from each other.

The DC voltage (bus voltage) at two levels of high potential (P) and low potential (N) from converter 2 is converted into a three-phase alternating voltage of variable voltage and variable frequency by inverter 3. The motor 4 of the elevator is driven by the three-phase AC voltage output from the inverter 3. [

A smoothing capacitor is connected between the converter 2 and the inverter 3 so as to connect between two busbars of high potential (P) and low potential (N). This smoothing capacitor is for smoothing the pulsation of the DC voltage which is the output of the converter 2. That is, the busbar voltage on the inverter 3 side input to the inverter 3 is the busbar voltage on the converter 2 side output from the converter 2 smoothed by the action of this capacitor.

Here, an electrolytic capacitor is used for the smoothing capacitor. However, when the voltage of the three-phase AC power supply 1 is 400 V, it is necessary to smooth the voltage signal of about 565 V (400 V) output from the converter 2 . However, in general, electrolytic capacitors rarely have a withstand voltage exceeding about 600 (V). A first condenser 5 and a second condenser 6, which are two general-purpose electrolytic capacitors having a high withstand voltage of several hundreds (V), are connected as a smoothing capacitor connected between the converter 2 and the inverter 3, Are connected in series.

In order to use the electrolytic capacitors connected in series, it is necessary to make the voltages applied to the first and second capacitors 5 and 6 equal. A first balance resistor 7 is connected in parallel to the first capacitor 5 and a second balance resistor 8 is connected in parallel with the second capacitor 6. The first and second capacitors 5 and 6 are connected in parallel, 2 are adjusted so that the voltages applied to the capacitors 6 become equal to each other.

The power conversion function for supplying the electric power for driving the motor 4 of the elevator, mainly of the control device of the elevator, is configured as described above. The control device of this elevator is provided with a detection circuit 9 for detecting abnormality of the bus voltage inputted to the inverter 3 and power supply abnormality in accordance with the alternating voltage supplied from the three-phase alternating-current power supply 1.

The detection circuit 9 includes two first capacitors 5 for smoothing the DC bus voltage of two levels of high potential P and low potential N input from the converter 2 to the inverter 3, 2 capacitor 6, and detects an abnormality of the DC bus voltage based on the intermediate potential. Further, the detection circuit 9 is grounded, and treats the intermediate potential of the first capacitor 5 and the second capacitor 6 as a ground voltage.

The configuration of the detection circuit 9 is shown in Fig. The intermediate potential VH of the first capacitor 5 and the second capacitor 6 input to the detection circuit 9 can be referred to as the intermediate potential between the first balance resistor 7 and the second balance resistor 8 Is input to the comparator 11 for under voltage detection and the comparator 12 for overvoltage detection and power supply abnormality detection after being depressed by the step-down circuit 10 provided in the detection circuit 9. [

The undervoltage detection comparator 11 compares the lowered intermediate voltage with a predetermined undervoltage detection reference voltage generated by the undervoltage detection reference voltage generating power source 13. [ As a result of the comparison, when the lowered intermediate voltage is equal to or higher than the reference voltage for undervoltage detection, the undervoltage detection comparator 11 outputs a comparison signal.

As will be described later, a periodicity is also observed in the waveform of the intermediate voltage VH input to the detection circuit 9 from the periodicity of the voltage waveform of the three-phase AC power supply 1. [ Therefore, when the coerced intermediate voltage is equal to or higher than the reference voltage for undervoltage detection, the comparison signal output from the undervoltage detection comparator 11 becomes a periodic rectangular pulse.

An output from the undervoltage detection comparator 11 is input to the undervoltage detection pulse generating device 14. [ The undervoltage detection pulse generator 14 generates a pulse of a predetermined first pulse period T1 as a trigger and outputs it as a detection signal. The first pulse period T1 is set to be equal to or longer than the period of the rectangular pulse of the comparison signal output from the undervoltage detection comparator 11 so that the undervoltage detection pulse The detection signal is continuously output from the generation device 14 and the detection signal can be prevented from being output from the undervoltage detection pulse generator 14 when the coerced intermediate voltage is not equal to or more than the undervoltage detection reference voltage have.

The detection signal outputted from the undervoltage detection pulse generator 14 is supplied to the inverter 15 through the inverter 15 so that the inverted intermediate voltage is lower than the reference voltage for undervoltage detection The signal is continuously outputted, and when the coerced intermediate voltage is equal to or higher than the reference voltage for undervoltage detection, no signal is output.

The overvoltage detection and power supply abnormality detecting comparator 12 is for detecting a predetermined overvoltage detection and power supply abnormality generated by the reference voltage generating power supply 16 for detecting the intermediate voltage and the overvoltage detection and power supply abnormality, Compare the reference voltage. If the intermediate voltage is lower than the reference voltage for overvoltage detection and power supply abnormality detection as a result of the comparison, the comparator 12 for overvoltage detection and power supply abnormality detection outputs a comparison signal.

The comparison signal output from the comparator 12 for overvoltage detection and power supply abnormality detection is also output from the above undervoltage detection comparator 11 when the lowered intermediate voltage is equal to or higher than the reference voltage for overvoltage detection and power supply error detection Like the comparison signal, which becomes a periodic rectangular pulse.

The output from the comparator 12 for overvoltage detection and power supply abnormality detection is input to the overvoltage detection and power supply abnormality detection pulse generation device 17. The overvoltage detection and power source abnormality detection pulse generation device 17 generates a pulse of a predetermined second pulse period T2 as a trigger and outputs it as a detection signal. This second pulse period T2 is set to be equal to or longer than the period of the rectangular pulse of the comparison signal outputted from the comparator 12 for overvoltage detection and power supply abnormality detection so that the coercive intermediate voltage becomes the reference voltage for overvoltage detection and power supply abnormality detection The detection signal continues to be output from the overvoltage detecting and power source abnormality detecting pulse generator 17. If the intermediate voltage is not higher than the reference voltage for overvoltage detection and power source abnormality detection, It is possible to prevent the detection signal from being output from the power supply abnormality detecting pulse generator 17.

The output from the inverter 15 and the output from the overvoltage detection and power source abnormality detection pulse generation device 17 are input to the OR circuit 18. When there is output of a signal from at least one of the inverter 15 and the overvoltage detection and power source abnormality detection pulse generation device 17, the OR circuit 18 outputs a signal.

Next, the operation of the detecting circuit 9, particularly of the control apparatus for an elevator configured as described above, will be described.

First, the ground voltage (phase voltage) of each phase of the three-phase alternating current supplied from the three-phase alternating-current power supply 1 has a phase difference of 120 degrees with respect to each other. Therefore, the voltages VR, VS, and VT of each phase of R, S, and T of the three-phase alternating current can be expressed by the following equations (1) to (4), assuming that the peak voltage of the phase voltage is A (V) Can be expressed by the expression. A graph of these waveforms is shown in Fig.

VR = A * sin (? T) ... (One)

VS = A * sin (? T-120) ... (2)

VT = A * sin (? T-240) ... (3)

ω = 360 ° * f ... (4)

At this time, the high potential side VP of the bus line voltage between the converter 2 and the inverter 3 becomes equal to the phase having the maximum ground voltage among VR, VS, and VT. Conversely, the low potential side VN of the bus line voltage becomes equal to the phase having the smallest ground voltage among VR, VS, and VT (Fig. 4 (a)). Therefore, VP can be represented by the following expressions (5) to (7), and VN can be expressed by the following expressions (8) to (10).

VP (30 °?? T? 150 °) = A * sin (? T) ... (5)

VP (150 °?? T? 270 °) = A * sin (? T-120 °) (6)

VP (0??? T? 30, 270?? T? 360) = A * sin (? T-240) (7)

VN (210 °?? T? 330 °) = A * sin (? T) ... (8)

VN (0??? T? 90, 330?? T? 360) = A * sin (? T-120) (9)

VN (90 °?? T? 210) = A * sin (? T-240 °) (10)

4 (b) shows a state in which the potential VP at the high potential side of the bus line voltage is lowered to a level equivalent to the potential VN at the low potential side. Conventionally, the abnormality of the bus voltage is detected in the state shown in Fig. 4 (b). In this state, the ground voltage of the potential VN on the low potential side is sufficiently high.

The intermediate potential VH input to the detection circuit 9 is the intermediate potential between the first capacitor 5 and the second capacitor 6 connected in series between the high potential side VP and the low potential side VN of the bus voltage. Therefore, this intermediate potential is expressed by the following equation (11).

VH = 1/2 * (VP + VN) ... (11)

Substituting the equations (5) to (10) into the equation (11), the following equations (12) to (14) are obtained.

A * sin (? T-120) + A * sin (? T-240) where VH (0 ° ≤ωT≤30 °, 150 ° ≤ωT≤210 °, 330 ° ≤ωT≤360 °) ) ... (12)

VH (30??? T? 90, 210?? T? 270) = 1/2 A * sin (? T) + A * sin (? T-120 ?? (13)

VH (90??? T? 150, 270??? T? 330) = 1/2 A * sin (? T) + A * sin (14)

(12) to (14), the following equations (15) to (17) are obtained.

VH (0??? T? 30, 150?? T210, 330?? T? 360) = A / 2 * sin (? T-180) (15)

VH (30 °?? T 90 °, 210 °? T? 270 °) = A / 2 * sin (? T-60 °) (16)

VH (90 °?? T? 150 °, 270 °?? T? 330 °) = A / 2 * sin (? T-300 °) (17)

A waveform graph of the intermediate potential VH represented by the expressions (15) to (17) is shown in Fig. Thus, it can be seen that the intermediate potential VH changes periodically at a frequency of 3f. It can also be seen that the amplitude of the intermediate potential VH becomes -A / 4? VH? A / 4. That is, the intermediate potential VH is 1/4 times of the peak voltage A of the phase potential of the three-phase AC power supply 1, and 1/4√3 times (approximately 15%) of the peak of the inter-bus voltage √3A do.

5 (a) and 5 (b) show an example in which the capacitance of the capacitors of the first condenser 5 and the second condenser 6 is changed. When the capacitances of the first capacitor 5 and the second capacitor 6 are changed in this manner, the waveforms of the high potential side VP and the low potential side VN of the bus voltage are close to the waveform of the intermediate potential VN, There is little change in the waveform.

As described above, when the three-phase AC power supply 1 is in the neutral ground, the intermediate potential VH of the high potential side VP and the low potential side VN of the bus is less than the phase potential of the three-phase AC power supply 1 or the bus line potential of the inverter 3 And the crest value of the intermediate potential VH changes in proportion to the phase potential of the three-phase AC power supply 1 or the bus line potential of the inverter 3. By detecting this intermediate potential VH, it is possible to monitor the phase potential of the three-phase AC power supply 1 and the abnormality of the bus line potential of the inverter 3.

Here, for example, the detection circuit 9 detects an undervoltage abnormality when the bus voltage of the inverter 3 is reduced by x% from the rated power supply voltage, based on the intermediate potential VH, Overvoltage abnormality shall be detected when the rated supply voltage is increased by more than y%. If the intermediate voltage input to the detection circuit 9 in the step-down circuit 10 is stepped down by z%, the voltage input to the undervoltage detection comparator 11 and the overvoltage detection and power supply abnormality detection comparator 12 is VH * (1-z / 100), and the value at the peak is A / 4 * (1-z / 100).

Therefore, in this case, the predetermined undervoltage detection reference voltage generated by the undervoltage detection reference voltage generating power source 13 can be obtained by using A0 (V) as the phase voltage of the rated power supply voltage, 4 * (1-z / 100) * (1-x / 100). Similarly, the predetermined reference voltage for overvoltage detection and power supply abnormality detection generated by the reference voltage generating power supply 16 for overvoltage detection and power supply abnormality detection is A0 / 4 * (1-z / 100) * (1 + y / 100).

Fig. 6 shows signal waveforms in the undervoltage detection comparator 11 and undervoltage detection pulse generator 14. Fig. In this manner, the voltage VH * (1-z / 100) input to the undervoltage detection comparator 11 is lower than the reference voltage A0 / 4 * (1-z / 100) ), The comparison signal output from the undervoltage detection comparator 11 becomes a spherical pulse wave having a frequency of 3f (Hz).

Thus, by setting the predetermined first pulse period T1 of the undervoltage detection pulse generator 14 to be equal to or longer than the period 1 / 3f (s), the input voltage to the undervoltage detection comparator 11 becomes undervoltage detection It is possible to continuously output the detection signal from the undervoltage detection pulse generator 14. In this case,

The signal waveforms in the overvoltage detection / power supply abnormality detection comparator 12 and the overvoltage detection / power supply abnormality detection pulse generation device 17 are as shown in Fig. Thus, the voltage VH * (1-z / 100) input to the overvoltage detection and power supply abnormality detection comparator 12 is compared with the reference voltage A0 / 4 * (1-z / 100 ) * (1 + y / 100), the comparison signal output from the comparator 12 for overvoltage detection and power supply abnormality detection is a spherical pulse wave having a frequency of 3f (Hz).

Therefore, similarly to the case of undervoltage detection, by setting the predetermined second pulse period T2 of the overvoltage detection and power source abnormality detection pulse generation device 17 to be equal to or longer than this period 1 / 3f (s) It is possible to continuously output the detection signal from the overvoltage detection / power source abnormality detection pulse generator 17 when the input voltage to the power source abnormality detecting comparator 12 is equal to or higher than the reference voltage for overvoltage detection and power source abnormality detection have.

However, in order to perform both the overvoltage detection and the power supply abnormality detection in the comparator 12 and the pulse generator 17, the second pulse period T2 is set to a time equal to or longer than the period 1 / f (s) . This point will be described next.

8 is a waveform graph of the three-phase alternating current and the intermediate potential VH when an abnormality (imaging) occurs in the three-phase alternating current of the three-phase alternating-current power supply 1. The high potential side bus line voltage VP and the low potential side bus line voltage VN at this time are represented by the following equations (18) to (21).

VP (0??? T? 150, 330??? T? 360) = A * sin (? T) (18)

VP (150 °?? T? 330 °) = A * sin (? T-120 °) (19)

VN (150 °?? T? 330) = A * sin (? T) ... (20)

VN (0??? T? 150, 330??? T? 360) = A * sin (? T-120) (21)

Therefore, the intermediate potential VH at this time can be obtained by the following equation (22) by substituting these equations (18) to (21) into the equation (11).

VH = 1/2 * (A * sin (? T) + A * sin (? T-120)) = A / 2 * sin (22)

From the expression (22) and the graph in Fig. 8, the intermediate potential VH input to the detection circuit 9 when an imaging abnormality occurs in the three-phase alternating-current power supply 1 has a peak value (amplitude ) Becomes A / 2 (V). Therefore, the peak value of the voltage input to the comparator of the detection circuit 9 is A / 2 * (1-z / 100), which is twice the normal value.

From such a situation, it is possible to detect an abnormality in image formation of the three-phase AC power supply 1 in the same manner as the detection of the overvoltage in the bus. FIG. 9 shows a signal state at the time of an abnormal phase of the three-phase AC power supply 1 in the overvoltage detection and power supply abnormality detection comparator 12 and the overvoltage detection and power supply abnormality detection pulse generation device 17 .

Here, as described above, the frequency of the intermediate potential VH at the time of image formation abnormality of the three-phase AC power supply 1 is f (Hz). Therefore, when the phase abnormality occurs in the three-phase AC power supply 1, the comparator 12 for overvoltage detection and power supply abnormality detection outputs a rectangular pulse having the frequency f (Hz) as a comparison signal. By setting the second pulse period T2 of the pulse generator 17 for overvoltage detection and power supply abnormality detection to be equal to or larger than 1 / f (s), when the overvoltage occurs in the bus line and when the three- The detection signal is continuously output from the overvoltage detection and power source abnormality detection pulse generation device 17 in both cases.

Further, in order to detect both the overvoltage abnormality of the bus and the phase abnormality of the three-phase AC power supply 1 by the overvoltage detection and power supply abnormality detection comparator 12, the reference voltage for overvoltage detection and power supply abnormality detection is determined The value of y must be set to 100 or less.

The output from the undervoltage detection pulse generator 14 is input to the OR circuit 18 through the inverter 15 and the output from the pulse generator 17 for overvoltage detection and power supply abnormality detection is input to the OR circuit 18 OR circuit 18 as shown in FIG. Therefore, when any of the under voltage of the bus line, the over voltage, and the phase abnormality of the three-phase AC power supply 1 occurs, the OR circuit 18 outputs the abnormality detection signal.

Although the description has been given of the case where the step-down circuit 10 is provided in the detection circuit 9, the step-down circuit 10 is not essential and the step-down circuit 10 may not be provided. In addition, even when the balance of the three-phase alternating-current power supply 1 is in equilibrium, the voltage of the neutral point changes. Therefore, the undervoltage detection comparator 11 and the overvoltage detection and power supply abnormality detection comparator 12 It is possible to detect that the balance of the three-phase alternating-current power supply 1 has become unbalanced.

Further, in the above-described configuration, when a current flows between the neutral portion of the neutral point of the three-phase AC power supply 1 and the ground portion of the detection circuit 9 of the control device, there is a possibility . Therefore, a filter for removing noise may be provided in the step-down circuit 10. Since the frequency of the detection object in the detection circuit 9 is 3f (Hz), by providing a first-order low-pass filter at, for example, a cutoff frequency 30f (Hz), the influence of high- can do. Specifically, when the frequency f of the three-phase alternating-current power supply 1 is 60 Hz, a noise of 9 kHz or more can be sufficiently attenuated by using a low-pass filter having a cutoff frequency of 1.8 kHz.

The controller of the elevator configured as described above notices that the intermediate potential of the bus line potential becomes a low potential with respect to the ground when the ground of the power source side is the neutral point grounding system and does not require a large scale down circuit, It is possible to detect an abnormality in the bus line DC voltage value of the 2-level inverter or an abnormality in the 3-phase AC supplied from the power supply.

By setting the reference voltage in the comparator and the pulse period of the pulse generator appropriately, it is also possible to detect power supply abnormality such as overvoltage detection and image formation of the bus by a comparator and a pulse generator.

Embodiment 2 Fig.

Fig. 10 and Fig. 11 show a configuration of a three-phase alternating-current power supply to a detection circuit of a control apparatus of an elevator according to a second embodiment of the present invention. Fig. ) Is a diagram for explaining a variation in the ground voltage of the bus.

In the configuration of the first embodiment described above, when electric power returns to the bus line from the motor 4 during the regenerative operation, the diode of the converter 2 is turned off. For this reason, the ground voltage of the bus line fluctuates within a range of certain constant uncertainty, as shown in Fig. In this case, since the intermediate potential also fluctuates, an abnormality can not be correctly detected except at the time of stopping or backward operation. Also, when the converter 2 is used with a regenerative converter (transistor converter), the ground potential of the bus line is changed by the switching of the converter.

Thus, the second embodiment described herein is a circuit configuration in which the diode bridge 19 and the first intermediate voltage generating resistor 20 and the second intermediate voltage generating resistor 20, which are different from the main circuit shown in Fig. 1 of the first embodiment, (21) are provided, and a detection circuit (9) is connected to them.

The three-phase alternating-current power supply 1 is also connected to a diode bridge 19 provided separately from the converter 2. The three-phase alternating-current voltage supplied from the three-phase alternating-current power supply 1 is converted into a direct-current voltage by the diode bridge 19. To the output of the diode bridge 19, a first intermediate voltage generating resistor 20 and a second intermediate voltage generating resistor 21 connected in series are connected. The impedance of the first intermediate voltage generating resistor 20 is the same as that of the first balanced resistor 7 and the impedance of the second intermediate voltage generating resistor 21 is the same as that of the second balanced resistor 8. [

The intermediate voltage between the first intermediate voltage generating resistor 20 and the second intermediate voltage generating resistor 21 becomes equal to the intermediate voltage VH of the first capacitor 5 and the second capacitor 6. [ In this way, the generated intermediate voltage VH is input to the detection circuit 9. Other configurations and operations including the configuration and operation of the detection circuit 9 are the same as those in the first embodiment. That is, the detection circuit 9 detects the intermediate voltage generated by the diode bridge 19, the first intermediate voltage generating resistor 20, and the second intermediate voltage generating resistor 21 provided separately from the main circuit, Based on the voltage VH, abnormality of the DC bus voltage or power supply abnormality is detected.

The control device of the elevator configured as described above can detect an accurate intermediate potential even in the case of the regenerative operation or the regenerative converter and correctly detect the abnormality of the bus voltage or the power supply abnormality.

Embodiment 3:

Fig. 12 and Fig. 13 are diagrams according to Embodiment 3 of the present invention, Fig. 12 is a circuit diagram showing a detection circuit included in the elevator control device, and Fig. 13 is a diagram exemplifying the detection target voltage waveform in the detection circuit .

In the configuration of the first embodiment or the second embodiment described above, the waveform of the voltage input to the comparator indicates a sinusoidal waveform that fluctuates in both upward and downward directions, whereas the reference voltage serving as a comparison reference in the comparator is a waveform . Therefore, when the equilibrium of the three-phase AC power supply 1 is lost for some reason and the potential is offset downward as a whole, there is a possibility that the abnormality can not be detected.

Thus, in the third embodiment described herein, the detection circuit 9 is provided with a full-wave rectification circuit 22 to rectify the downward displacement of the intermediate potential VH in the upward direction, . Therefore, since the potential on the lower side of the intermediate potential VH is also compared in the comparator, it is possible to detect an abnormality in which the equilibrium of the three-phase AC power supply 1 is off balance for some reason and the potential is offset downward as a whole.

Other configurations and operations are the same as those in Embodiment 1 or Embodiment 2, and detailed description thereof will be omitted.

Embodiment 4.

Fig. 14 is a diagram showing a detection circuit portion included in the elevator control apparatus according to Embodiment 4 of the present invention. Fig.

In the fourth embodiment described here, the extracted intermediate potential VH is converted into a digital signal by the A / D converter 23, and then abnormality of the DC bus voltage or power supply anomaly is detected. The intermediate potential VH converted into a digital signal by the AD converter 23 is input to the CPU 24 that performs digital signal processing by calculation. The CPU 24 realizes the functions of the detection circuit 9 of the first to third embodiments described above by digital signal processing. As described above, by detecting the abnormality of the DC bus voltage based on the intermediate potential VH or the detection of the power supply abnormality by the digital signal processing, it is possible to perform the abnormality with higher accuracy and stronger against the noise. Other configurations and operations are the same as those of the first to third embodiments, and detailed description thereof will be omitted.

[Industrial Availability]

The present invention relates to a three-phase alternating-current power supply of a neutral point grounding type which supplies electric power to a main circuit of an elevator, and a converter for converting a three-phase alternating-current voltage from the three-phase alternating-current power supply into two levels of high- And an inverter for converting an AC voltage of two levels from the converter into an AC voltage to drive an elevator motor.

1: Three phase AC power source
2: Converter
3: Inverter
4: Motor
5: First capacitor
6: Second capacitor
7: first balance resistance
8: second balance resistance
9: Detection circuit
10: Step-down circuit
11: Comparator for Undervoltage Detection
12: Comparator for overvoltage detection and power supply fault detection
13: Reference voltage generating power source for undervoltage detection
14: Pulse generator for undervoltage detection
15: Reversal
16: Overvoltage detection and reference voltage generation power source for power supply fault detection
17: Pulse generator for overvoltage detection and power supply fault detection
18: OR circuit
19: Diode bridge
20: Resistance for generating the first intermediate voltage
21: Second intermediate voltage generating resistor
22: Full wave rectifier circuit
23: AD converter
24: CPU

Claims (9)

A three-phase alternating-current power supply of a neutral point grounding method for supplying power to a main circuit of an elevator and a three-phase alternating-current power supply for converting a three-phase alternating-current voltage from the three- And an inverter for converting the two-level direct-current voltage from the converter to an alternating-current voltage to drive the motor of the elevator,
A first capacitor and a second capacitor provided between the converter and the inverter and connected in series between a high potential side and a low potential side of the two levels of DC voltage;
And detecting means for detecting, as an intermediate voltage, a voltage between the ground and the ground of the connecting portion of the first capacitor and the second capacitor,
Wherein the detecting means detects an abnormality of the two-level DC voltage inputted to the inverter based on the detected intermediate voltage. The method according to claim 1,
Wherein the detecting means detects an abnormality of the three-phase alternating-current voltage supplied from the three-phase alternating-current power supply based on the detected intermediate voltage. The method of claim 2,
Wherein the detecting means detects both of an abnormality of the two-level DC voltage and an abnormality of the three-phase AC voltage by comparing the detected intermediate voltage with a predetermined reference voltage. The method according to claim 1,
And a filter that removes a high frequency component of a predetermined frequency or more from the detected intermediate voltage,
Wherein the detecting means detects an abnormality of the two-level DC voltage based on the intermediate voltage from which the high-frequency component has been removed by the filter. The method according to claim 1,
And a full-wave rectification circuit for rectifying the detected intermediate voltage by the detection means,
Wherein the detecting means detects an abnormality of the two-level DC voltage based on the intermediate voltage rectified by the full-wave rectifying circuit. The method according to claim 1,
And conversion means for converting the detected intermediate voltage into a digital signal by the detection means,
Wherein said detecting means detects abnormality of said two-level DC voltage by digital signal processing based on said intermediate voltage converted into a digital signal by said converting means. The method according to claim 2 or 3,
And a filter that removes a high frequency component of a predetermined frequency or more from the detected intermediate voltage,
Wherein the detecting means detects an abnormality of the two-level DC voltage and an abnormality of the three-phase AC voltage based on the intermediate voltage from which the high-frequency component has been removed by the filter. The method according to claim 2 or 3,
And a full-wave rectification circuit for rectifying the detected intermediate voltage by the detection means,
Wherein the detecting means detects an abnormality of the two-level DC voltage and an abnormality of the three-phase AC voltage based on the intermediate voltage rectified by the full-wave rectifying circuit. The method according to claim 2 or 3,
And conversion means for converting the detected intermediate voltage into a digital signal by the detection means,
Wherein said detecting means detects abnormality of said two-level DC voltage and abnormality of said three-phase AC voltage by digital signal processing based on said intermediate voltage converted into a digital signal by said converting means Lt; / RTI >

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