Method for controlling an elevator drive and a control device for carrying out the method

Abstract

In a method for controlling an elevator drive, particularly a passenger and / or goods elevator, a drive motor (14) of the elevator drive (11), connected to a power supply network (15), drives a cable (12) rotatably connected to it. The cable (12), which supports one of the elevator cars, causes the car to be raised or lowered with or without a payload when it is moved by the drive motor (14). The power of the drive motor (14) for the cable (12) can be varied by an electrical control system (20) such that the drive motor (14) supplies the cable (12), and thus the car, with a limited drive power, at least when lifting with a full or nearly full payload, so that the travel speed of the car is reduced compared to when carrying a partial payload.Based on the determined full or nearly full payload, the drive motor (14) is controlled accordingly by the control system (20). In this process, the operation is automatically and optimally adapted to these given operating conditions.

Description

[0001] The invention relates to a device for controlling an elevator drive, in particular a passenger and / or goods elevator, in which a cable connected to a rotary cable is driven by means of at least one drive motor of the elevator drive connected to a power consumer network, wherein the cable supporting an elevator cabin causes the cabin to be raised or lowered with or without a payload when adjusted by the drive motor, and a control device for carrying out the method, according to the preamble of claim 1 or claim 7.

[0002] Publication EP 3 566 996 A1 discloses an elevator with a rope for raising and lowering an elevator car on the one hand and a counterweight supported by it on the other. The rope is guided by means of a drive pulley, preferably rotatably connected to a motor at its upper end, and around at least one pulley of a support pulley arrangement held on the counterweight.

[0003] The counterweight is advantageously installed in the elevator with a weight equal to the cabin weight and, typically, half the payload. The payload, defined as the cabin's capacity, is determined by the cabin size, such as the number of passengers. This results in the lowest torque at the motor compared to other weight ratios, and therefore the lowest required power output. This counterweight load balancing means the motor requires the same power output when traveling downwards with an empty cabin as when traveling upwards with a full cabin, because the counterweight, weighing half the additional payload, must be pulled upwards during downward travel. The power output, or motor power, is dimensioned so that the cabin always travels at the same speed in both directions.

[0004] If the counterweight is reduced to, for example, 30% of the given payload, the required maximum torque at the motor increases because the power output when the cabin is full going upwards is 70% of the payload, while when the cabin is empty going downwards it is only 30% of the payload. This weight distribution is used because a lighter counterweight reduces power consumption over the operating period. This is because, especially in passenger elevators, it is rare for them to travel upwards with a full payload, as is often the case in residential buildings. However, a disadvantage of this type of elevator is that the torque or connected load of the elevator drive must be increased to deliver the necessary power when carrying a full payload.

[0005] While elevators without a counterweight have the advantage of requiring less space, the disadvantage is that the cabin weight and the payload, i.e. 100% of the total mass, must be lifted or carried by the drive motor both when going up and down.

[0006] The invention is based on the objective of creating a method for controlling an elevator drive for an elevator with or without a counterweight, by which the elevator operates more economically and is better adapted to the operating conditions.

[0007] This problem is solved according to the invention by the features of claim 1.

[0008] According to the invention, in the control method, the power of the drive motor for the cable pull can be changed by an electrical control system in such a way that the drive motor supplies the cable pull and thus the cabin with a limited drive power, at least when lifting in the state with a full or nearly full payload, so that the travel speed of the cabin is reduced compared to that when not fully loaded, wherein at least the full or nearly full payload is determined and evaluated by the control system, which controls the drive motor accordingly.

[0009] This inventive method achieves significant savings in elevator operation, even though the elevator primarily travels at its normal speed. Based on the fact that the elevator usually does not operate at full payload, because in addition to empty runs, it is typically loaded with a reduced payload (a phenomenon known from statistical experience with elevators), the inventive method automatically optimizes the elevator's operation according to these given operating conditions.

[0010] It is highly advantageous to use an asynchronous motor as the drive motor, which is operatively connected to a frequency converter associated with the electrical control system in such a way that the frequency and / or the voltage of the drive motor, and thus its speed, can be varied. This allows for simple and effective control of the drive motor.

[0011] It is advantageous for the frequency converter to determine the maximum torque at the drive shaft of the drive motor, at least during start-up, and to transmit this information to the control system for evaluating and controlling the drive motor. This determination of at least the full or nearly full payload can also be achieved by measuring the cabin load, current, and / or by using another measuring device before and / or during cabin start-up.

[0012] The control system is advantageously programmed in such a way that the cabin is always moved up and down at the same speed, regardless of the prevailing payload, except when it is moving with a full or nearly full payload during lifting.

[0013] The inventive method allows elevators to be operated with or without a counterweight and achieves the aforementioned advantages.

[0014] A control device according to the invention for carrying out the method is associated with an electrical control system for the drive motor, by which the power from the consumer network to the drive motor for the cable pull or the cabin can be varied. With this control device, the intended power limitation can be carried out very efficiently and safely.

[0015] The invention and further advantages thereof are explained in more detail below with reference to exemplary embodiments and the drawing. It shows: Fig. 1 shows a diagram of the cabin's power consumption during travel time as an abscissa, with the load increasing with full payload and decreasing with empty payload, where the counterweight corresponds to the cabin weight plus 50% of the payload or 35% of the payload, respectively, which corresponds to the prior art; Fig. 2 shows a diagram of the cabin's power consumption according to the invention during travel time as an abscissa, with the load increasing with full payload and decreasing with empty payload, respectively, where the counterweight corresponds to the cabin weight plus 50% or 35% of the payload, compared to the known cabin power consumption with a counterweight corresponding to the cabin weight plus 50% of the payload; Fig.3. A diagram of an elevator without a counterweight, showing the course of the cabin's power consumption according to the invention during travel time as the abscissa as a function of the payload upwards as the ordinate, with the cabin weight plus 100% or 70% of the payload, respectively, in comparison with the known power consumption of the cabin without a counterweight, which corresponds to the cabin weight plus 100% of the payload; and Fig. 4. An electrical schematic diagram of the elevator drive control according to the invention.

[0016] An elevator, not shown in detail, is equipped with a cabin that is typically height-adjustable along guide rails in an elevator shaft. The cabin can travel between several floors, and lockable doors are provided on each floor for access. The cabin is held by a cable and moved up and down along the guide rails. The cable, which runs through the elevator shaft, is driven longitudinally by a drive pulley connected to it and belonging to the elevator's drive motor.

[0017] The elevator is a passenger and / or goods elevator, constructed in the conventional manner and suitable for installation in any building, tower, freestanding glass shaft or the like.

[0018] In the elevator, the cable is advantageously guided around the drive pulley of the drive motor, which is preferably located at the top, and around a support pulley assembly of a counterweight that can be adjusted up and down in the elevator shaft, as explained in the aforementioned publication EP 3 566 996 A1. Naturally, the arrangement of the cable and the counterweight can be varied according to requirements. Several of these counterweights and / or cables can also be used.

[0019] In a cable winch, several cables are preferably used side by side. However, at least one belt can also be used instead of cables, or a combination of both. In a simpler design, the cable winch can just as easily be attached to the counterweight on one side and to the cabin on the other, and guided around the drive pulley located at the top of the shaft.

[0020] The elevator can also be designed without a counterweight, for example, if space is limited or if it is a simple, cost-effective design intended for installation in a building. Such an elevator is described in detail in patent application no. CH000571 / 2024 and is therefore not further described here.

[0021] In the method for controlling the elevator drive, a drive motor of the elevator drive connected to a power consumer network is used to control and drive a rope pull connected to it, and thus the cabin, whereby the rope pull supporting the cabin of the elevator causes the cabin to be raised or lowered with or without payload when it is adjusted by the drive motor.

[0022] Fig. 1 This figure shows the power ratings P35 and P50 of a lift cabin according to the state of the art. These ratings are plotted as a function of the travel time tK (abscissa) against the power ratings Pup and Pdown during the cabin's ascending and descending movements (ordinates). The power rating increases during acceleration up to a maximum, which then remains constant and decreases to zero when the cabin stops at a floor. The figures illustrate the required power ratings Pup with a full load going upwards and Pdown with an empty load going downwards. The power ratings are calculated by multiplying the voltage by the current.

[0023] For these connection capacities P 50 and P 35, a counterweight is assumed in each case, which in the case of P 50 corresponds to the cabin weight plus 50% of the payload, and in the case of P 35 to the cabin weight plus 35% of the specified payload of the cabin.

[0024] At power ratings P 35 and above, the power rating is higher than at P 50 because the counterweight is lighter and pulls less weight downwards. Conversely, when descending with an empty cabin, the power rating is higher at P 50 because the heavier counterweight requires more power to pull it upwards. When the cabin is partially loaded, the power ratings are lower than the two maximum ratings shown. When descending with a loaded cabin, the power rating is lower anyway due to gravity.

[0025] According to the invention, the connected power of the drive motor for the cabin is changed by an electrical control system in such a way that the drive motor supplies the cable pull and thus the cabin with a limited drive power, at least when lifting in the state with full or nearly full payload, so that the travel speed of the cabin is reduced compared to that when not fully loaded.

[0026] Before or during the lifting of the cabin, the system determines at least the full or nearly full payload, and if this is the case, the drive motor is controlled accordingly by the control system; that is, if the control system is informed that the full payload is present, the drive power is reduced.

[0027] The drive motor for the cable pull and thus for the cabin, designed as an asynchronous motor, is very advantageously connected to a frequency converter assigned to the electrical control system in such a way that the frequency and / or the voltage of the drive motor and thus its speed can be changed proportionally.

[0028] The control system is programmed so that the cabin always travels up and down at the same speed, regardless of the actual payload, as long as it is not carrying a full or near-full load when lifting. This constant speed is the same as that of conventional elevators. A near-full load can be between 90% and 99% of the full load, or possibly even lower.

[0029] Fig. 2 Figure 50 shows the curve of the connected loads P50.1 and P50.2 of a cabin of an elevator according to the inventive method, in which these are illustrated as a function of the travel time tK on the abscissa and the power P up and P down during ascending and descending travel of the cabin on the ordinate, respectively. In addition, the curve of the known connected load P50 is shown, as also in Fig. 1 As can be seen, the comparison is shown. The power output increases during acceleration up to a maximum, which then remains constant and decreases to zero again when the cabin stops at a floor. This curve can also be configured differently. The required power outputs are shown for full payload upwards and at 70% of the full payload, with the counterweight corresponding to the cabin weight plus 50% of the specified cabin payload, as specified for the P 50.

[0030] This results in reduced connected loads P 50.1 and P 50.2, which, as can be seen, differ by a power difference P Dif compared to the known connected load P 50. With P 50.1 and a full payload, the cabin travels a correspondingly longer time t 3 - t 2, totaling t 3 - t 1, for example, from one floor to the next or across several floors. In contrast, with P 50.2 and the lower payload of 70%, the travel time is the same as with the known power P 50. This power reduction saves energy, and the electrical components for the control system and the elevator drive can be made smaller and therefore more cost-effective.

[0031] When descending with an empty cabin according to Fig. 2 The connected load is higher at P 50 because the connected load at P 50.1 is reduced due to the lifting of the smaller counterweight. When the cabin is partially loaded, the connected loads are less than the two maximum loads shown. When descending with a loaded cabin, the load is reduced anyway due to gravity, as mentioned above.

[0032] Such a power reduction can of course also be provided for a different counterweight mass, for example as in P 35, where it corresponds to the cabin weight plus 35% of the specified cabin payload. In P ab, with an empty payload and below, the power reduction could then not be activated or could be omitted, because the required power output is lower anyway.

[0033] Fig. 3 Figure 1 shows another variant of the power ratings P0.1 and P0.2 of a cabin in an elevator according to the inventive method, in which no counterweight is present. The power ratings P0.1 and P0.2 are shown at full payload and at 70% of the full payload respectively when traveling upwards, as is provided for a power rating P0 without a counterweight and without power reduction. The power ratings are illustrated as a function of the travel time tK (abscissa) to the power P during upward travel of the cabin (ordinate). The curve of the known power rating P50 is also shown, as in [reference missing]. Fig. 1 This is shown for comparison, but without a counterweight. The connected loads are higher with the same payload than when a counterweight is used, and they increase during start-up up to a maximum power, remain constant, and then decrease to zero when the cabin stops at a floor, at which point the motor is switched off.

[0034] Fig. 4 Figure 1 shows a schematic diagram of a control device 10 according to the invention for the elevator drive 11 for carrying out the method, which is associated with an electrical control system 20 for the elevator drive 11, by which the connected load from the power consumer network 15 to the drive motor 14 of the cable pull 12 can be changed. The power consumer network 15 is generally connected to the public grid with a frequency of 50 Hz and a voltage of 220 V or 380 V. Accordingly, a three-phase asynchronous motor is used as the drive motor 14.

[0035] The electrical control system 20 is associated with a frequency converter 22, which interacts with the drive motor 14 in such a way that the frequency and / or the mains voltage generated by the power consumer network 15 is converted, thereby allowing the speed of the drive motor to be varied. The frequency converter 22 can also determine the torque at the drive shaft 16 of the drive motor 14 and transmit it via a signal line 17 to the control system 20 for evaluation and control of the drive motor 14. This allows for a very efficient determination, when starting up to lift the cabin, of whether the full or nearly full payload is present, so that, if necessary, the drive motor 14 is controlled by the control system 20 via the frequency converter 22 with the reduced power input P 50.1.The speed of the drive motor 14 and consequently the travel speed of the cabin is then a function of the required torque and the power limit set in the control system 20.

[0036] The determination of at least the full or nearly full payload can be carried out instead of the torque at the drive shaft by a load measurement of the cabin, a current measurement of the mains current and / or by another measuring device, by which corresponding measurement signals are transmitted to the control system 20 for evaluation, which then serve to control the drive motor 14.

[0037] If the electrical control system 20 receives information from the relevant determination before or during starting that the cabin is not loaded or not nearly loaded with full load, the control system 20 will control the drive motor 14 in such a way that the faster predetermined travel speed of the cabin is achieved, which is always the same whether there is an empty weight or a partial load in the cabin, and which usually changes with each stop because people get in and out or goods are loaded or unloaded.

[0038] In principle, the power output of the drive motor for the cable pull 12 could be varied by the electrical control system 20 such that the drive motor 14 could control the cable pull 12, and thus the cabin, at least during lifting, with two or more different limited power outputs, with or without a counterweight. The same power output could be used in the state with a full or nearly full payload, as in the embodiment described above for P 50.1. A second, less restricted power output could be used for a payload less than nearly full, but, for example, higher than 70% of the payload. A third, less restricted power output could be used for a payload of less than 70%, but higher than 50%. For payloads below 50%, the normal travel speed would then be set as in P 50.This gradation would allow for further energy and cost savings in the elevator drive.

[0039] The invention is sufficiently demonstrated by the above exemplary embodiments. However, it could be further explained by other variations. For example, instead of a frequency converter for the control system, a frequency inverter, a frequency converter and / or another electrical device could also be used.

[0040] Alternatively, a DC motor could be used instead of an asynchronous motor, in which the power could be varied analogously.

Claims

1. Method for controlling an elevator drive, in particular a passenger and / or goods elevator, in which a rope pull (12) rotatably connected to a power consumer network (15) is driven by means of at least one drive motor (14) of the elevator drive (11) connected to a power consumer network (15), wherein the rope pull (12) supporting a cabin of the elevator causes the cabin to be raised or lowered with or without payload when it is adjusted by the drive motor (14), characterized by the fact that the power of the drive motor (14) for the cable pull (12) can be varied by an electrical control system (20) such that the drive motor (14) can drive the cable pull (12) and thus the cabin, at least when lifting in the state with full or nearly full payload, with a limited drive power (P). 50.1 , P 0.1) supplied, so that the travel speed of the cabin is reduced compared to the state when not fully loaded, whereby the drive motor (14) is controlled accordingly by the control system (20) based on the at least determined full or nearly full load.

2. Method according to claim 1, characterized by the fact that The drive motor (14), designed as an asynchronous motor or the like, is operatively connected to a frequency converter (22) associated with the electrical control system (20) in such a way that the frequency and / or the voltage of the drive motor (14) and thus its speed can be changed.

3. Method according to claim 2, characterized by the fact that The frequency converter (22) determines the torque at the drive shaft of the drive motor (14), at least during start-up, and transmits it to the control system (20) for evaluating and controlling the drive motor.

4. Method according to any one of claims 1 to 3, characterized by the fact thatThe determination of at least the full or nearly full payload is carried out by measuring the cabin load, current and / or by another measuring device before and / or during the cabin start-up, by which corresponding measurement signals are transmitted to the control system (20) for evaluation, which then serve to control the drive motor (14).

5. Method according to any one of claims 1 to 4, characterized by the fact that the control system (20) is programmed such that the cabin is always moved up and down at the same speed regardless of the prevailing payload in it, except when it is moving with a full or nearly full payload during lifting.

6. Method according to any one of claims 1 to 5, characterized by the fact thatthe control system (20) is programmed such that, in addition to the reduced travel speed when lifting in the state with full or nearly full payload, the cabin is also controlled with at least one further limited travel speed, particularly when lifting the cabin, for example when the payload is less than the nearly full payload, but preferably more than half of the full payload.

7. Control device for an elevator drive, in particular for a passenger and / or goods elevator, for carrying out the method according to one of claims 1 to 6, characterized by the fact thatThe control device (10) is assigned an electrical control system (20) for the drive motor (14), by which the power from the electrical consumer network (15) to the drive motor of the cable pull (12) can be changed in such a way that the cabin can be supplied with a limited drive power at least when lifting in the state with full or nearly full payload and thus its travel speed is reduced compared to the state with not full payload.

8. Control device according to claim 7, characterized by the fact that the drive motor (14) is designed as an asynchronous motor or the like and the electrical control system has a frequency converter (22), the latter being controlled in such a way as to interact with the drive motor (14) that the frequency and thus the speed of the drive motor can be changed.

9. Control device according to claim 7 or 8, characterized by the fact thatThe speed of the drive motor (14) for the cable pull (12) can be adjusted by the electrical control system (20) with at least two different speeds depending on the state of the payload when the cabin is moved up or down by the frequency converter (22) measuring the torque.

10. Control device according to one of claims 7 to 9, characterized by the fact that The determination of at least the full or nearly full payload is carried out by means of a load measurement of the cabin, a current measurement and / or by means of another measuring device, through which corresponding measurement signals can be transmitted to the control system (20) for evaluation thereof.

11. Control device according to one of claims 7 to 10, characterized by the fact thatThe control device is provided with limited drive power for a cabin without or with at least one counterweight connected to it, wherein the counterweight is provided with a weight load determined in relation to that of the cabin.

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