JP7003965B2 - Passenger conveyor - Google Patents

Description

The present invention relates to a passenger conveyor.

Patent Document 1 discloses a passenger conveyor having a switch for switching a connection state of a regenerative resistor that converts regenerative power into heat energy.

Japanese Unexamined Patent Publication No. 2016-171699

If the semiconductor switch that switches the connection state of the regenerative resistor fails, the DC stage voltage inside the inverter is continuously applied to the braking resistor, and the braking resistor may overheat.

The present invention provides a passenger conveyor capable of appropriately detecting a failure of a semiconductor switch that switches the connection state of a braking resistor.

The passenger conveyor of the present invention
A motor that circulates and drives the steps connected in an endless manner,
A converter unit that converts AC power supplied from AC power to DC power,
The inverter section that converts the DC power converted by the converter section into AC power and supplies it to the motor.
Semiconductor switches and braking resistors connected in series between the positive and negative power lines that connect the output of the converter section and the input of the inverter section,
With a control unit,
The control unit
When the AC power supply is not out of power, the semiconductor switch is controlled to OFF, and the regenerative power generated by the motor is sent to the AC power supply via the inverter section and converter section.
When the AC power supply fails, the semiconductor switch is controlled to be ON for a predetermined time after the power failure occurs, and the regenerative power generated by the motor is energized to the braking resistor via the inverter and the semiconductor switch.
The control unit
If the braking resistor is energized at a time other than the specified time, it is determined that the semiconductor switch has a short-circuit failure.

According to the passenger conveyor of the present invention, it is possible to appropriately detect the failure of the semiconductor switch that switches the connection state of the braking resistor.

It is a schematic side view of the escalator in Embodiment 1. FIG. It is a figure which showed the electric structure of the inverter of the escalator in Embodiment 1. FIG. It is a flowchart explaining the control by the controller of the inverter at the time of the descending operation of the escalator in Embodiment 1. It is a flowchart explaining the control by the controller of the inverter at the time of the descending operation of the escalator in Embodiment 1.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Background of invention)
For example, when the user is on board more than a certain amount while the escalator is in the descending operation, regenerative power is generated to rotate the motor shaft in the direction opposite to the descending operation direction due to the weight of the user. In the configuration where power is supplied from the inverter to the motor, a braking resistor is placed outside the inverter to prevent the voltage of the DC stage capacitor inside the inverter (between the rectifying section and the inverter section) from continuing to rise due to regenerative power. At the same time, the inverter has a built-in semiconductor switch, and the semiconductor switch controls the energization of the regenerative power to the braking resistor, while the braking resistor consumes the regenerative power to prevent the DC stage capacitor voltage from rising. is doing. Further, by consuming the regenerative power with the braking resistor, the regenerative braking of the escalator becomes possible.

Here, if the semiconductor switch built in the inverter causes a short-circuit failure, the capacitor voltage of the DC stage inside the inverter is continuously applied to the braking resistor, which may cause the braking resistor to overheat.

As a method of detecting overheating, for example, there is a method of detecting overheating of the braking resistor itself. However, the braking resistor is in a state of overheating to some extent even in a normal state, and the overheating level of the braking resistor changes depending on the rise of the escalator. Therefore, in order to properly judge the abnormality, it is necessary to set the overheating level individually, which causes a problem that the judgment of the abnormality becomes complicated.

In view of this, the present invention provides a passenger conveyor capable of appropriately detecting a failure of a semiconductor switch that switches a connection state of a braking resistor.

(Embodiment 1)
1. 1. Configuration Figure 1 is a schematic side view of the escalator according to the first embodiment. The escalator 1 is an example of a passenger conveyor.

The escalator 1 includes an escalator main body 10, a motor 20, an inverter 30, a control device 40, and the like.

The escalator main body 10 is installed in a state of being bridged between two floors F1 and F2 of the building. The escalator main body 10 has a plurality of steps 11 connected in an endless manner, a pair of left and right endless handrails 12, and a power transmission mechanism for transmitting the power of the motor 20 to the steps 11 and the handrail 12. The plurality of steps 11 and the handrail 12 are circulated and driven by the power of the motor 20 driven by the electric power supplied from the inverter 30. Floors F1 and F2 are provided with entrances 5 and 6 for users to get on and off. The entrances 5 and 6 are entrances or exits depending on the driving direction.

The inverter 30 inputs AC power, converts the frequency of the input AC power, and supplies it to the motor 20.

The motor 20 operates at a rotation speed corresponding to the frequency of the AC power supplied from the inverter 30. As a result, the drive speed of the step 11 is changed according to the frequency of the AC power supplied from the inverter 30. The motor 20 is composed of, for example, an induction motor.

The control device 40 controls the operation of the escalator 1. The control device 40 is configured by using, for example, a programmable logic controller (PLC). The control device 40 outputs a deceleration signal to the inverter 30 when it becomes necessary to stop the escalator 1 due to the operation of the safety device or when a power failure occurs.

FIG. 2 is a diagram showing an electrical configuration of an inverter of an escalator according to the first embodiment.

The inverter 30 includes a converter unit 31, a capacitor 32, an inverter unit 33, a braking transistor 34, a braking resistor 35, a controller 36, and a voltage measuring unit 37.

The converter unit 31 inputs three-phase AC power from the AC power supply PS side, converts it into DC power (AC → DC conversion), and outputs it to the inverter unit 33 side. Further, the converter unit 31 inputs DC power from the inverter unit 33 side when regenerative power is generated in the motor 20, and converts it into three-phase AC power that matches the voltage, frequency, and phase of the AC power supply PS (DC → AC). Convert) and output to the AC power supply PS side. The converter unit 31 is composed of, for example, a plurality of transistors or the like. The converter unit 31 performs the above-mentioned AC → DC conversion and DC → AC conversion by controlling the ON / OFF timings of the plurality of transistors by the controller 36.

The capacitor 32 smoothes the DC power output from the converter unit 31. Further, the capacitor 32 smoothes the DC power output from the inverter unit 33 when the regenerative power is generated. The capacitor 32 may be any capacitor such as an electrolytic capacitor as long as it can smooth DC power.

The inverter unit 33 inputs DC power from the converter unit 31 side, converts it into three-phase AC power having a voltage and frequency suitable for the operation of the motor 20 (DC → AC conversion), and outputs the DC power to the motor 20 side. Further, the inverter unit 33 inputs regenerative power (three-phase AC power) from the motor 20 side, converts it into DC power (AC → DC conversion), and outputs it to the converter unit 31 side, for example, during deceleration control. The inverter unit 33 is composed of, for example, a plurality of transistors or the like. The inverter unit 33 performs the above-mentioned DC → AC conversion and AC → DC conversion by controlling the ON / OFF timings of the plurality of transistors by the controller 36.

The braking transistor 34 controls the energization of the braking resistor 35. Specifically, the braking transistor 34 is controlled to be ON for a predetermined time by the controller 36 during deceleration control during a power failure. The braking transistor 34 is an example of a semiconductor switch. The predetermined time T0 is the time required to realize the predetermined deceleration rate described later in the deceleration control, or a time slightly longer than the time. The predetermined time T0 is, for example, 2 seconds.

The braking resistor 35 is composed of, for example, a cement resistor. The braking resistor 35 converts the energized electric power into heat and consumes it. The braking resistor 35 and the braking transistor 34 are connected in series between the positive and negative power lines connecting the output of the converter unit 31 and the input of the inverter unit 33.

The voltage measuring unit 37 measures the voltage between both terminals of the braking resistor 35.

The controller 36 controls the operation of the inverter 30 by controlling the operation of each of the above-mentioned components in the inverter 30. The controller 36 is configured by using, for example, a programmable logic controller (PLC). The programmable logic controller (PLC) includes a control unit and a storage unit. The storage unit stores programs and various data. The program includes a program for realizing various functions of the controller 36 of the present embodiment. The control unit reads a program and data from the storage unit, and performs arithmetic processing based on the read program and data. As a result, various functions in the controller 36 are realized.

The escalator 1 further includes a power supply voltage monitoring device 70.

The power supply voltage monitoring device 70 monitors the voltage of the AC power supply PS. The power supply voltage monitoring device 70 outputs a power failure signal to the control device 40 when the voltage of the AC power supply PS becomes 0 V, for example, due to a power failure or the like.

2. 2. Operation The operation of the escalator 1 during the descending operation will be described below.

FIG. 3 is a flowchart illustrating control by the control device 40 during the descending operation of the escalator 1. The process shown in the flowchart of FIG. 3 is started when an escalator activation operation is performed on the key switch of the escalator operation panel by an escalator administrator or the like.

When there is an escalator activation operation, the controller 36 activates the escalator 1 (S11). At this time, the controller 36 outputs a start signal to the inverter 30.

The control device 40 determines whether or not a power failure of the AC power supply PS has occurred (S12). When the control device 40 receives, for example, a power failure signal from the power supply voltage monitoring device 70, the control device 40 determines that a power failure has occurred.

When no power failure has occurred (NO in S12), the control device 40 determines whether or not the operation stop condition is satisfied (S13). The control device 40 determines that the operation stop condition is satisfied when the safety device for detecting the abnormality of the escalator 1 is activated or when the escalator is stopped.

If the operation stop condition is not satisfied (NO in S13), the control device 40 returns to step S12 and executes the determination again.

When the operation stop condition is satisfied (YES in S13), the control device 40 executes an operation stop process for stopping the operation of the escalator 1 (S14). The control device 40 outputs a deceleration signal to, for example, the inverter 30.

If it is determined in step S12 that a power failure has occurred (YES in S12), the control device 40 executes an operation stop process in order to respond to the power failure (S14). The control device 40 outputs a deceleration signal to, for example, the inverter 30.

FIG. 4 is a flowchart illustrating control by the controller 36 of the inverter 30 during the downward operation of the escalator 1. The process shown in the flowchart of FIG. 3 is started when the escalator administrator or the like has an escalator start operation for the key switch of the escalator operation panel and the start signal is output from the control device 40 to the controller 36 of the inverter 30. ..

Upon receiving the start signal from the control device 40, the controller 36 performs a start process for operating the inverter 30 (S21). At this time, the controller 36 controls the braking transistor 34 to OFF.

When the startup process is performed, the controller 36 determines whether or not a power failure of the AC power supply PS (commercial power supply or the like) has occurred (S22). The controller 36 may determine by itself that the AC voltage for operating the inverter 30 has disappeared, or determines that a power failure has occurred when a power failure signal is received from the power supply voltage monitoring device 70 of the escalator 1. May be good.

When a power failure has not occurred (NO in S22), the controller 36 determines whether or not a deceleration signal has been received from the control device 40 (S23). The control device 40 transmits a deceleration signal when a power failure has not occurred, for example, when the safety device is activated.

When the deceleration signal is not received (NO in S23), the controller 36 executes, for example, the following normal controls (1) and (2). (1) AC power supply Three-phase AC power is input from PS, and the input three-phase AC power is converted into three-phase AC power with a voltage and frequency suitable for steady operation by the converter unit 31, inverter unit 33, and the like, and the motor 20. Output to. (2) When regenerative power is generated by the motor 20 due to a large number of passengers while the escalator is in a descending operation, the regenerative power generated by the motor 20 is input, and the input regenerative power is used by the inverter unit 33, the converter unit 31, etc. Converts it into three-phase AC power that matches the voltage, frequency, and phase of the AC power PS and outputs it to the AC power PS. In the normal control of (1) and (2), the controller 36 controls the braking transistor 34 to OFF.

When the deceleration signal is received (YES in S23), the controller 36 executes the non-power failure deceleration control of the following (3) for a predetermined time T0 (S25), stops the escalator 1, and ends the processing of this flowchart. do. (3) While controlling the motor 20 to decelerate at a predetermined deceleration rate, the regenerative power generated by the motor 20 due to the deceleration is input, and the input regenerative power is used by the inverter unit 33, the converter unit 31, and the like to control the voltage of the AC power supply PS. It is converted into three-phase AC power that matches the frequency and phase and output to the AC power supply PS. The predetermined deceleration rate is a deceleration rate at which the impact applied to the user while riding on the escalator 1 becomes a predetermined degree or less when the escalator 1 is stopped. In the non-power failure deceleration control (3), the controller 36 controls the braking transistor 34 to OFF.

When it is determined in step S22 that a power failure has occurred (YES in S22), the controller 36 executes the following (4) power failure deceleration control for a predetermined time T0 (S26). (4) The inverter 30 controls the motor 20 to decelerate at a predetermined deceleration rate, inputs the regenerative power generated by the motor 20 due to the deceleration, converts the input regenerative power into DC power by the inverter unit 33, etc., and brakes. The braking resistor 35 is energized and consumed via the transistor 34. The predetermined time T0 is, for example, 2 seconds as described above. In the deceleration control at the time of power failure, the controller 36 controls the braking transistor 34 to be ON for a predetermined time T0.

After the execution of step S26, the controller 36 controls the braking transistor 34 to OFF (S27).

The controller 36 determines whether or not the voltage between the terminals of the braking resistor 35 is 0 (V) (S28).

When the voltage between the terminals of the braking resistor 35 is 0 (V) (YES in S28), the controller 36 ends the process of this flowchart.

When the voltage between the terminals of the braking resistor 35 is not 0 (V) (NO in S28), the controller 36 determines that a braking transistor abnormality has occurred (S29). At this time, the controller 36 may output a braking transistor abnormality signal to the control device 40.

3. 3. Action of this embodiment The action of the escalator 1 of the embodiment will be described.

In the escalator 1 of the present embodiment, depending on the situation in which the escalator 1 is placed, the above-mentioned normal control (1) to (2), (3) non-power failure deceleration control, or (4) power failure Time deceleration control is performed.

For example, when the motor 20 generates regenerative power due to a large number of passengers while the escalator is in a descending operation, the normal control (2) is performed. As a result, the regenerative power generated by the motor 20 can be converted into three-phase AC power matching the voltage, frequency, and phase of the AC power supply PS by the inverter 30 and output to the AC power supply PS. Further, when the safety device is activated, the deceleration control at the time of non-power failure (3) is performed. This makes it possible to perform deceleration control for decelerating the motor 20 at a predetermined deceleration rate. Further, the regenerative power generated by the motor 20 due to deceleration can be converted into three-phase AC power matching the voltage, frequency, and phase of the AC power supply PS by the inverter 30 and output to the AC power supply PS.

In particular, in any of the controls (2) and (3), the regenerative power generated by the motor 20 due to deceleration is not energized to the braking resistor 35, so that the braking resistor 35 is not overheated.

Further, when a power failure occurs during the descent operation, the deceleration control at the time of the power failure according to (4) is performed. At this time, the controller 36 controls the braking transistor 34 to be ON for a predetermined time T0. This makes it possible to control the motor 20 to decelerate at a predetermined deceleration rate. Further, the regenerative power generated by the motor 20 due to deceleration can be converted into DC power by the inverter unit 33, and the braking resistor 35 can be energized and consumed via the braking transistor 34. The energization time to the braking resistor 35 is only the predetermined time T0 (for example, 2 seconds) described above.

According to the above configuration, the braking resistor 35 is energized only in the case of the deceleration control at the time of power failure in (4). Further, the energization time is only the predetermined time T0 after the power failure is detected, and the predetermined time T0 is a short time of about 2 seconds as described above. Therefore, it is possible to prevent the braking resistor 35 from overheating. If the temperature of the braking resistor 35 is allowed to rise within a range that does not cause a problem, the braking resistor 35 can be downsized. In this case, the cost of the braking resistor 35 can also be reduced.

In particular, in the present embodiment, the braking transistor 34 is configured to be turned on only at T0 for a predetermined time only when a power failure occurs. Therefore, when the voltage between the terminals of the braking resistor 35 is T0 or more and not 0 (V) for a predetermined time, it means that the braking resistor 35 has a short-circuit failure. Therefore, in the present embodiment, whether or not the voltage between the terminals of the braking resistor 35 is T0 or more for a predetermined time and is not 0 (V) is determined to determine whether the braking transistor 34 has a short-circuit failure. You can properly judge whether or not it is.

(Summary of embodiments)
(1) The escalator 1 (an example of a passenger conveyor) of the first embodiment is
A motor 20 that circulates and drives the step 11 connected in an endless manner, and
A converter unit 31 that converts AC power supplied from the AC power supply PS into DC power, and
The inverter unit 33 that converts the DC power converted by the converter unit 31 into AC power and supplies it to the motor 20.
A braking transistor 34 (an example of a semiconductor switch) and a braking resistor 35 connected in series between positive and negative power lines connecting the output of the converter unit 31 and the input of the inverter unit 33.
With a controller 36 (control unit)
The controller 36
When the AC power supply PS is not out of power, the braking transistor 34 is controlled to OFF, and the regenerative power generated by the motor 20 is passed to the AC power supply PS via the inverter unit 33 and the converter unit 31.
When the AC power supply PS fails, the braking transistor 34 is controlled to be ON for a predetermined time T0 from the occurrence of the power failure, and the regenerative power generated by the motor 20 is transmitted to the braking resistor 35 via the inverter unit 33 and the braking transistor 34. Energize and
The controller 36
When the braking resistor 35 is energized at a time other than T0 for a predetermined time, it is determined that the braking transistor 34 has a short-circuit failure.

According to the escalator 1 of the first embodiment, it is possible to appropriately detect the failure of the braking transistor 34 that switches the connection state of the braking resistor 35.

(2) In the escalator 1 of the first embodiment
A voltage measuring unit 37 for measuring the voltage between terminals of the braking resistor 35 is provided.
When the voltage between terminals is not 0 volt when the time is other than T0, the controller 36 determines that the braking transistor 34 has caused a short-circuit failure.

According to this, by measuring the voltage between the terminals of the braking resistor 35, it is possible to easily determine the short-circuit failure of the braking resistor 35.

(Other embodiments)
(A)
The escalator 1 of the above embodiment is an example of the passenger conveyor of the present invention. In the present invention, the passenger conveyor may be a passenger conveyor such as a so-called moving walkway arranged horizontally or diagonally on one floor.

(B)
In the first embodiment, the voltage measuring unit 37 for measuring the voltage between the terminals of the braking resistor 35 is provided, and the controller 36 short-circuits the braking transistor 34 when the voltage between the terminals is not 0 volt except for a predetermined time T0. Judge that it is out of order. However, instead of or in combination with this, a current measuring unit for measuring the current flowing through the braking resistor 35 is provided, and the controller 36 has a braking transistor 34 when the current is not 0 amperes at times other than T0 for a predetermined time. It may be determined that a short-circuit failure has occurred. According to this, by measuring the current of the braking resistor 35, it is possible to easily determine the short-circuit failure of the braking resistor 35.

(C)
In the first embodiment, the braking transistor 34 is exemplified as the semiconductor switch. However, in the present invention, the semiconductor switch may be any semiconductor switch that controls energization.

(D)
In the first embodiment, an example is shown in which the determination (S28) of whether or not the voltage between the terminals of the braking resistor 35 is 0 (V) is executed immediately after the step S27. However, the determination of whether or not the voltage between the terminals of the braking resistor 35 is 0 (V) may be executed at any timing other than the timing at which step S26 is executed. In the present invention, the semiconductor switch is controlled to be ON for a predetermined time after the occurrence of a power failure. Therefore, if the voltage between the terminals of the braking resistor 35 is not 0 (V) when the time is other than T0, the braking transistor 34 is short-circuited. This is because it can be said that a failure has occurred.

1 Escalator 5 Entrance / exit 6 Entrance / exit 10 Escalator body 11 Step 12 Handrail 20 Motor 30 Inverter 31 Converter 32 Condenser 33 Inverter 34 Braking transistor 35 Braking resistor 36 Controller 40 Control device F1 Floor F2 Floor

Claims (3)

A motor that circulates and drives the steps connected in an endless manner,
A converter unit that converts AC power supplied from AC power to DC power,
An inverter unit that converts DC power converted by the converter unit into AC power and supplies it to the motor.
A semiconductor switch and a braking resistor connected in series between the positive and negative power lines connecting the output of the converter section and the input of the inverter section.
With a control unit,
The control unit
When the AC power supply is not out of power, the semiconductor switch is controlled to OFF, and the regenerative power generated by the motor is passed to the AC power supply via the inverter unit and the converter unit.
When the AC power supply fails, the semiconductor switch is controlled to be ON for a predetermined time from the occurrence of the power failure, and the regenerative power generated by the motor is energized to the braking resistor via the inverter unit and the semiconductor switch. After that, the semiconductor switch is controlled to OFF, and the semiconductor switch is turned off .
The control unit
When the braking resistor is energized even though the semiconductor switch is controlled to be OFF at a time other than the predetermined time during which the semiconductor switch is controlled to be ON, the semiconductor switch is short-circuited. Judging that it is causing
Passenger conveyor. A voltage measuring unit for measuring the voltage between the terminals of the braking resistor is provided.
When the voltage between the terminals is not 0 volt even though the semiconductor switch is controlled to be OFF when the control unit controls the semiconductor switch to be ON at a time other than the predetermined time, the semiconductor is controlled. Judge that the switch has a short-circuit failure,
The passenger conveyor according to claim 1. A current measuring unit for measuring the current flowing through the braking resistor is provided.
When the current is not 0 amperes even though the semiconductor switch is controlled to be OFF when the control unit controls the semiconductor switch to be ON at a time other than the predetermined time, the semiconductor switch is controlled. Judge that a short circuit failure has occurred,
The passenger conveyor according to claim 1 or 2.

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