CONTROL DEVICE FOR A PASSENGER TRANSPORT SYSTEM

Abstract

An electrical control device for controlling the drive of a passenger transport system which can be switched between load operation and idle operation is described. The electrical control device includes at least a three-phase mains voltage connection, a frequency converter, and a controllable switching device. The switching device can couple the three phases of the drive motor to the three phases of the mains voltage connection in a load operation switching state and to the three phases of the frequency converter in an idle operation switching state. In this manner, the drive motor is supplied with the three-phase mains voltage in the load operation switching state and with the three-phase output voltage of the frequency converter in the idle operation switching state.

Claims

1-14. (canceled)

15. An electrical control device for controlling a drive of a passenger transport system that can be switched between load operation and idle operation, wherein the passenger transport system comprises an escalator or moving walkway and includes a three-phase drive motor, the electrical control device comprising: a three-phase mains voltage connection for supplying a three-phase mains voltage; a frequency converter that can be controlled at least with regard to a frequency of a three-phase output voltage; a controllable switching device having: a load operation switching state in which three phases of the three-phase drive motor can be coupled to three phases of the three-phase mains voltage connection, and an idle operation switching state in which the three phases of the three-phase drive motor can be coupled to the three phases of the frequency converter, wherein the three-phase drive motor is supplied with the three-phase mains voltage in the load operation switching state and with the three-phase output voltage of the frequency converter in the idle operation switching state, wherein the frequency converter is supplied via at least one phase the three-phase mains voltage connection and a neutral conductor of the three-phase mains voltage connection.

16. The electrical control device of claim 15, wherein a frequency converter supply voltage is applied to supply the frequency converter, which frequency converter supply voltage is smaller than the three-phase mains voltage by a factor of 1/3.

17. The electrical control device of claim 16, wherein the three-phase mains voltage is three times 400 volts and the three-phase output voltage of the frequency converter has a range from three times 0 to 230 volts.

18. The electrical control device of claim 16, wherein the three-phase mains voltage is three times 380 volts and the three-phase output voltage of the frequency converter has a range from three times 0 to 220 volts.

19. The electrical control device of claim 15, wherein the frequency converter comprises a rectifier module having a diode bridge circuit connected, on its input side, to a phase of the three-phase mains voltage connection and to the neutral conductor.

20. The electrical control device of claim 15, wherein the frequency converter comprises a rectifier module having a diode arrangement, which rectifier module is connected, on its input side, to each phase of the three-phase mains voltage connection, wherein the three phases are combined via a diode in a same reverse direction and form a positive pole of a DC voltage circuit of the frequency converter and the neutral conductor forms a negative pole of the DC voltage circuit.

21. The electrical control device of claim 15, wherein the frequency converter comprises a rectifier module having a diode arrangement, which rectifier module is connected, on its input side, to each phase of the three-phase mains voltage connection, wherein the three phases are combined via a diode in a same reverse direction and form a negative pole of a DC voltage circuit of the frequency converter and the neutral conductor forms a positive pole of the DC voltage circuit.

22. The electrical control device of claim 15, wherein the controllable switching device can be controlled by a controller of the passenger transport system.

23. The electrical control device of claim 15, further comprising a phase synchronization module that synchronizes a converter frequency of the three-phase output voltage of the frequency converter with a mains frequency of the three-phase mains voltage connection and triggers a switching process of the controllable switching device depending on the mains frequency and converter frequency.

24. A passenger transport system configured as an escalator or moving walkway, the passenger transport system comprising: a controller; a three-phase drive motor; and the electrical control device of claim 15, wherein the controller is connected via a wired or wireless signal connection to the electrical control device.

25. The passenger transport system of claim 24, wherein the controller is connected via the wired or wireless signal connection to the frequency converter or the controllable switching device.

26. The passenger transport system of claim 24, further comprising at least one transport requirement signal transmitter that detects and transmits a transport requirement to the controller as a sensor signal such that, depending on the sensor signal, the controller controls the frequency converter and the controllable switching device.

27. A method for controlling the drive of the passenger transport system of claim 24, wherein the controller controls the controllable switching device such that the three-phase drive motor of the drive is supplied with: the three-phase mains voltage of three times 400 volts during load operation, and the three-phase output voltage of the frequency converter of three times 0 to 230 volts during idle operation.

28. The method of claim 27, wherein the passenger transport system further comprises at least one transport requirement signal transmitter that detects and transmits a transport requirement to the controller as a sensor signal, wherein, depending on the sensor signal, the controller controls the frequency converter and the controllable switching device.

29. A method for controlling the drive of the passenger transport system of claim 24, wherein the controller controls the controllable switching device such that the three-phase drive motor of the drive is supplied with: the three-phase mains voltage of three times 380 volts during load operation, and the three-phase output voltage of the frequency converter of three times 0 to 220 volts during idle operation.

30. The method of claim 29, wherein the passenger transport system further comprises at least one transport requirement signal transmitter that detects and transmits a transport requirement to the controller as a sensor signal, wherein, depending on the sensor signal, the controller controls the frequency converter and the controllable switching device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Further advantages, features and details of the disclosure can be found in the following description of embodiments and with reference to the drawings, in which like or functionally like elements are provided with identical reference signs. The drawings are merely schematic and are not to scale. In the drawings:

[0026] FIG. 1 shows a passenger transport system which is designed as an escalator or moving walkway, and has at least a controller, a three-phase drive motor, and an electrical control device;

[0027] FIG. 2 is a diagram showing the various possible operating states;

[0028] FIG. 3A shows a rectifier module of the frequency converter in a first embodiment;

[0029] FIG. 3B shows a rectifier module of the frequency converter in a second embodiment; and

[0030] FIG. 3C shows a rectifier module of the frequency converter in a third embodiment.

DETAILED DESCRIPTION

[0031] FIG. 1 shows a passenger transport system 1, which is designed as an escalator. The components of the passenger transport system 1 that are visible to a user are a continuously movable conveyor belt 3 having steps 5. Balustrades 7 with continuously movable handrails 9 extend on the left and right sides of the conveyor belt 3. The return of the handrails 9 and the conveyor belt 3 takes place within the passenger transport system 1 and is therefore hidden from the users. The transport requirement signal transmitters 11 that monitor the access region 13 of the passenger transport system 1 are also hidden. In the present embodiment, the transport requirement signal transmitters 11 are radar sensors which are arranged behind handrail inlet caps 15 so as to be hidden. The detection region 17 thereof is indicated by a dash-dotted line.

[0032] As indicated by the broad arrow, a controller 21, a three-phase drive motor 25 and an electrical control device 23 are also accommodated within the passenger transport system 1. The three-phase drive motor 25 acts on the conveyor belt 3 and the handrails 9 via a transmission (not shown) and can drive same. The controller 21 controls and regulates the driving operation of the passenger transport system 1, as shown by way of example in FIG. 2 described below.

[0033] As shown in FIG. 1, the electrical control device 23 comprises at least a three-phase mains voltage connection 31, a frequency converter 33, and a controllable switchover device 35.

[0034] The three-phase mains voltage connection 31 is used to supply a three-phase mains voltage U.sub.N via the three phases R, S, T and also has a neutral conductor N. In the present embodiment, the neutral conductor N and the phase R of the mains voltage connection 31 are connected to a rectifier module 37 of the frequency converter 33 and supply a supply voltage U.sub.AC. Various embodiments, including those in which all three phases R, S, T and the neutral conductor N of the mains voltage connection are connected to the rectifier module 37, are described below with reference to FIG. 3A to 3C.

[0035] The frequency converter 33 also has a DC voltage circuit 39, which is supplied by the rectifier module 37. Depending on the configuration of the rectifier module 37, it can be useful if the direct voltage U.sub.DC in the DC voltage circuit 39 is smoothed by means of a capacitor 41. The DC voltage circuit 39 in turn supplies a converter module 43 of the frequency converter 33. The converter module 43 can be controlled with regard to its three-phase output voltage U.sub.AC1, U.sub.AC2, U.sub.AC3 For this purpose, the frequency converter 33 can be activated by the controller 21, as is indicated by the double arrow S.sub.1 shown with a broken line. The output voltages U.sub.AC1, U.sub.AC2, U.sub.AC3 are output by the converter module 43 via three phases U.sub.1, V.sub.1, W.sub.1.

[0036] The three phases U.sub.1, V.sub.1, W.sub.1 are connected to a first switch arrangement 51 of the controllable switching device 35. The three phases R, S, T of the mains voltage connection 31 are also connected to a second switch arrangement 53 of the controllable switching device 35. Both switch arrangements 51, 53 are switched by an actuator 55 of the controllable switching device 35, the actuator 55 also being activated by the controller 21 as indicated by the double arrow S.sub.2 shown with a broken line. Double arrows S.sub.1, S.sub.2 are used here because a bidirectional signal flow is provided. On the one hand, control commands are transmitted from the controller 21 to the frequency converter 33 or to the controllable switching device 35 and, on the other hand, the current states thereof are sent back to the controller 21.

[0037] The controllable switching device 35 has the task of switching between a load operation switching state B2 and an idle operation switching state B1 (see FIG. 2), the three phases U.sub.2, V.sub.2, W.sub.2 of the drive motor 25 being coupled to the three phases R, S, T of the mains voltage connection 31 in the load operation B2, while the three phases U.sub.1, V.sub.1, W.sub.1 of the converter module 43 are decoupled from the three phases U.sub.2, V.sub.2, W.sub.2 of the drive motor 25. In the idle operation switching state B1, if the couplings are exactly the opposite, then the three phases U.sub.2, V.sub.2, W.sub.2 of the drive motor 25 are coupled to the three phases U.sub.1, V.sub.1, W.sub.1 of the converter module 43 and the three phases R, S, T of the mains voltage connection 31 are decoupled from the three phases U.sub.2, V.sub.2, W.sub.2 of the drive motor 25. In other words, the drive motor 25 is supplied with a three-phase mains voltage U N in load operation and with the three-phase output voltage U.sub.AC1, U.sub.AC2, U.sub.AC3 of the frequency converter 33 in idle operation.

[0038] As already described, the passenger transport system 1 has transport requirement signal transmitters 11 in the access regions 13. A user can be detected by these signal transmitters when he steps toward the access region 13 of the passenger transport system 1 in order to enter same. The transport requirement signal transmitter 11 thus detects a transport requirement and thus an imminent load operation. A detected transport requirement is transmitted to the controller 21 as a sensor signal S.sub.3, the controller 21, depending on this sensor signal S.sub.3, controlling the controllable frequency converter 33 and the controllable switching device 35.

[0039] In order to show the interaction of the mains voltage connection 31, the frequency converter 33 and the controllable switching device 35, an exemplary speed curve 61 is shown in FIG. 2 during various possible operating states. The speed V of the conveyor belt 3 is plotted on the ordinate and the time t is plotted on the abscissa. The various operating states are described below with reference to FIGS. 1 and 2.

[0040] At the time 0, for example, an approaching user is detected by the transport requirement signal transmitter 11 and reported to the controller 21 as a transport requirement. This upregulates the three-phase output voltage U.sub.AC1, U.sub.AC2, U.sub.AC3 of the frequency converter 33, the controllable switching device 35 being switched to the idle operation switching state B1. In other words, the three-phase output voltage U.sub.AC1, U.sub.AC2, U.sub.AC3 of the frequency converter 33 is supplied to the drive motor, while the drive motor 25 is separated from the three-phase mains voltage connection 31. Between the times 0 and 1, the frequency converter 33 is upregulated so that the speed curve 61 of the conveyor belt 3 and the handrails 9 increases in a ramp-like manner up to the nominal speed V.sub.N.

[0041] At the time 1, at which the user has approximately reached the conveyor belt 3, it is at the nominal speed V.sub.N. The controller 21 can now send a switching signal S 2 to the controllable switching device 35. With the switching, the three-phase drive motor 25 is decoupled from the frequency converter 33 and connected to the three phases R, S, T of the mains voltage connection 31. The controllable switching device 35 has thus changed from the idle operation switching state B1 to the load operation switching state B2 in order to supply the three-phase drive motor 25 with sufficient electrical energy to transport users without a loss of speed.

[0042] At the time 2, the user has left the passenger transport device 1. This time can be calculated from the travel time t and the nominal speed V.sub.N, for example. Alternatively, the signal from the transport requirement signal transmitter 11 arranged at the other access region 13 can of course also be used, which can register the departure of the user and report it to the controller 21. From the time 2, the speed V of the conveyor belt 3 and the handrails 9 can be reduced again if no new user approaches. To reduce the speed V, the controllable switching device 35 is switched from the load operation switching state B2 back to the idle operation switching state B1 at time 2, the output voltages U.sub.AC1, U.sub.AC2, U.sub.AC3 of the frequency converter 33 first being upregulated before the switching process and then downregulated in the manner of a ramp after the switching process.

[0043] With regard to further operation, there may be two options:

[0044] In a first variant, the conveyor belt 3 can be brought to a standstill P in the idle operation switching state B1, which standstill, in the present example, is reached at point 4 and remains in place until point 5. As soon as the transport requirement signal transmitter 11 again reports a transport requirement (here at time 5), the drive motor 25 is started up by means of the frequency converter 33 in a manner analogous to that already described for times 0 to 1 and when the nominal speed V N is reached at time 7, the switching process by the controllable switching device 35 from the idle operation switching state B1 to the load operation switching state B2 takes place.

[0045] In a second variant, the conveyor belt 3 can be put into what is known as a crawl S in the idle operation switching state B1, the crawl speed Vs corresponding, for example, to half of the nominal speed V.sub.N. The crawl speed V s is then kept constant, as shown by the dash-dotted line, until a transport requirement is registered again at the time 5. The drive motor is then started up again by means of the frequency converter 33 until, after the nominal speed V N is reached at time 6, the switching process by the controllable switching device from the idle operation switching state B1 to the load operation switching state B2 takes place. As can be clearly seen from the diagram, the conveyor belt 11 in the second variant reaches the nominal speed V N much earlier and the switching process can take place earlier.

[0046] If the phase zero crossings of the mains voltage connection 31 are shifted in relation to the phase zero crossings of the output voltages U.sub.AC1, U.sub.AC2, U.sub.AC3 of the frequency converter 33 during the switching process, this can lead to undesirable additional loads for the mechanical and electrical components of the passenger transport system 1. In order to avoid this, the electrical control device 23 can have a phase synchronization module 63. This phase synchronization module 63 synchronizes the converter frequency of the three-phase output voltage U.sub.AC1, U.sub.AC2, U.sub.AC3 of the frequency converter 33 with the mains frequency of the three-phase mains voltage connection 31, by, for example, the phase zero crossings being detected by sensors 65, 67 and the IGBT (not shown) of the converter module 43 being controlled accordingly, so that the zero crossings of the three phases U.sub.1, V.sub.1, W.sub.1 and the phase position thereof match the corresponding phases R, S, T of the mains voltage connection 31. The phase synchronization module 63 then triggers the switching process of the controllable switching device 35 depending on the synchronized mains frequency and converter frequency. As shown, the entire logic of the phase synchronization module 63 can be implemented in the controller 21 of the passenger transport system 1. Of course, the phase synchronization module 63 can also be implemented separately from the controller 21.

[0047] As already described above and shown in FIG. 1, the rectifier module 37 of the frequency converter 33 is supplied by at least one phase R and the neutral conductor N of the mains voltage connection 31. In other words, a frequency converter supply voltage U.sub.AC is applied to supply the frequency converter 66, which supply voltage is smaller than the three-phase mains voltage U.sub.N by a factor of 1/3 or a factor of 1/1.73.

[0048] With a three-phase mains voltage U N of, for example, three times 400 volts, the frequency converter supply voltage U.sub.AC is therefore 230 volts. After the rectification, a direct voltage U.sub.DC is present in the direct voltage circuit 39, which direct voltage varies depending on the load. The three-phase output voltage U.sub.AC1, U.sub.AC2, U.sub.AC3 of the converter module 43 supplied by the direct voltage circuit 39 can be varied in a range of three times to 230 volts due to the existing DC voltage U.sub.DC, provided that this DC voltage is approximately sinusoidal. With a three-phase mains voltage U N of three times 380 volts, the frequency converter supply voltage is 220 volts and correspondingly the three-phase output voltage U.sub.AC1, U.sub.AC2, U.sub.AC3 of the frequency converter 33 can be varied in each case in a range of three times 0 to 220 volts.

[0049] The frequency converter 33 can have differently configured rectifier modules 37. The rectifier module 37 shown in FIG. 3A has a diode bridge circuit 71. This bridge circuit is connected on its input side 77 to a phase R and to the neutral conductor N of the three-phase mains voltage connection 31. The direct voltage U.sub.DC generated by the bridge circuit 71 is output to the downstream DC voltage circuit 39 of the frequency converter 33 and smoothed there by means of a capacitor 41.

[0050] The rectifier module 37 shown in FIG. 3B has a diode arrangement 73 deviating from the bridge circuit 71 and is connected, on its input side 77, to each phase R, S, T of the three-phase mains voltage connection 31. The three phases R, S, T are each brought together via a diode with the same reverse direction in such a way that only the positive half-waves are allowed to pass due to the reverse direction and the positive pole of the DC voltage circuit 39 of the frequency converter 33 is thus formed. In this case, the neutral conductor N forms the negative pole of the DC voltage circuit 39.

[0051] The rectifier module 37 shown in FIG. 3C has a diode arrangement 75 which is almost identical to the previously described diode arrangement of FIG. 3B and is also connected to the neutral conductor N and the three phases R, S, T of the three-phase mains voltage connection 31. The three phases R, S, T are each brought together via a diode with the same reverse direction in such a way that only the negative half-waves are allowed to pass due to the reverse direction and the negative pole of the DC voltage circuit 39 of the frequency converter 33 is thus formed. In this case, the neutral conductor N forms the positive pole of the DC voltage circuit 39.

[0052] Although FIG. 1 shows a passenger transport system 1 designed as an escalator, it is obvious that the present invention can also be used in a passenger transport system 1 designed as a moving walkway.

[0053] Finally, it should be noted that terms such as comprising, having, etc., do not preclude other elements or steps and terms such as a or an do not preclude a plurality. Furthermore, it should be noted that features or steps that have been described with reference to one of the above embodiments may also be used in combination with other features or steps of other embodiments described above. Reference signs in the claims should not be considered to be limiting.