Elevator control device and control method

Abstract

Provided are an elevator control device and a control method with which such a confinement that a rescue operation for causing a cage to travel in a powering direction is impossible hardly occurs. In a control device (100), an inverter (8) drives a hoisting machine motor (9) for causing the cage of an elevator to travel. A smoothing capacitor (7) stabilizes the voltage of a DC bus line connected to the inverter (8). A regenerative resistor (10) consumes the regenerative power generated by the hoisting machine motor (9) during the regenerative operation of the elevator. A threshold setting unit (15) sets a voltage threshold value so that the remaining lifetime of the inverter (8) predicted by a second lifetime prediction unit (17) becomes longer than the remaining lifetime of a regenerative switching element (11) predicted by a first lifetime prediction unit (16). A switching control unit (13) controls, on the basis of a relationship between the voltage detection value of the DC bus line and the set voltage threshold value, the switching operation of the regenerative switching element (11) for switching the presence or absence of current flow into the regenerative resistor (10).

Description

[Technical Field]

[0001] The present disclosure relates to an elevator control device and control method. [Background technology]

[0002] Patent Document 1 discloses an example of an elevator, in which a lifespan estimation circuit for estimating the lifespan of an inverter is provided in a control device for the elevator. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2009-12929 Summary of the Invention [Problem to be solved by the invention]

[0004] Even when the inverter's lifespan is estimated, as in the elevator of Patent Document 1, early replacement of inverter components may not be possible before the estimated lifespan due to management reasons. In such cases, inverter failure may cause the elevator to make an emergency stop. When the elevator makes an emergency stop, passengers inside the car may become trapped. In this case, if the inverter is faulty, rescue operation cannot be performed, in which the car is powered and stopped at floor level.

[0005] The present disclosure relates to solving such problems, and provides an elevator control device and control method that make it less likely for passengers to be trapped, making rescue operation by running the car in the power running direction impossible. [Means for solving the problem]

[0006] an inverter that drives a hoist motor that drives an elevator car; a smoothing capacitor that stabilizes the voltage of a DC bus connected to the inverter; a regenerative resistor that is connected to the DC bus and consumes regenerative power generated by the hoist motor during regenerative operation of the elevator; a regenerative switching element that switches on and off the flow of current to the regenerative resistor; a first voltage monitoring unit that detects the voltage of the DC bus; a threshold setting unit that sets a voltage threshold that determines the timing of the switching operation of the regenerative switching element; a switching control unit that controls the switching operation of the regenerative switching element based on the relationship between the voltage value detected by the first voltage monitoring unit and the voltage threshold set by the threshold setting unit; a first life prediction unit that predicts the remaining life of the regenerative switching element; and a second life prediction unit that predicts the remaining life of the inverter, wherein the threshold setting unit sets the voltage threshold so that the remaining life of the inverter predicted by the second life prediction unit is longer than the remaining life of the regenerative switching element predicted by the first life prediction unit.

[0007] The elevator control method according to the present disclosure includes an inverter that drives a hoisting machine motor that runs a car, a smoothing capacitor that stabilizes the voltage of a DC bus connected to the inverter, a regenerative resistor that is connected to the DC bus and consumes regenerative power generated by the hoisting machine motor during regenerative operation, a regenerative switching element that switches whether or not a current flows into the regenerative resistor, a first voltage monitoring unit that detects the voltage of the DC bus, and a switching control unit that controls the switching operation of the regenerative switching element based on the relationship between the voltage value detected by the first voltage monitoring unit and a voltage threshold that determines the timing of the switching operation of the regenerative switching element. and a threshold setting step of setting the voltage threshold so that the remaining life of the inverter predicted in the second prediction step is longer than the remaining life of the regenerative switching element predicted in the first prediction step. [Effects of the Invention]

[0008] With the elevator control device or control method according to the present disclosure, it becomes less likely that passengers will be trapped in a manner that makes rescue operation, in which the car travels in the power running direction, impossible. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a configuration diagram of an elevator control device according to a first embodiment. [Figure 2A] 4A to 4C are diagrams illustrating an example of the switching operation of the regenerative switching element during regenerative operation of the elevator according to the first embodiment. [Figure 2B] 4A to 4C are diagrams illustrating an example of the switching operation of the regenerative switching element during regenerative operation of the elevator according to the first embodiment. [Figure 3] 3 is a diagram illustrating an example of the transition of the remaining life span of an inverter and a regenerative switching element in the elevator control device according to the first embodiment, and an example of the setting of a voltage threshold value. FIG. [Figure 4A] 3 is a diagram illustrating an example of prediction of the remaining life of an inverter or a regenerative switching element in the elevator control device according to the first embodiment. FIG. [Figure 4B] 3 is a diagram illustrating an example of prediction of the remaining life of an inverter or a regenerative switching element in the elevator control device according to the first embodiment. FIG. [Figure 5A] FIG. 2 is a diagram illustrating an example of determining whether an open fault has occurred in a regenerative switching element in the elevator control device according to the first embodiment. [Figure 5B] FIG. 2 is a diagram illustrating an example of determining whether an open fault has occurred in a regenerative switching element in the elevator control device according to the first embodiment. [Figure 6] 2 is a hardware configuration diagram of a main part of a control device according to the first embodiment. FIG. [Figure 7] FIG. 10 is a configuration diagram of an elevator control device according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] The following describes embodiments of the subject matter of the present disclosure with reference to the accompanying drawings. In each drawing, identical or corresponding parts are designated by the same reference numerals, and redundant explanations are appropriately simplified or omitted. Note that the subject matter of the present disclosure is not limited to the following embodiments, and any component of the embodiments may be modified or omitted within the scope of the gist of the present disclosure.

[0011] Embodiment 1 FIG. 1 is a configuration diagram of an elevator control device according to the first embodiment.

[0012] Elevators are used in buildings with multiple floors. An elevator shaft (not shown) is provided in the building. The shaft is a long vertical space spanning multiple floors. The elevator has a car (not shown). The car is placed in the shaft. The car's load is supported by a main rope (not shown). The car travels up and down the shaft, transporting elevator users between multiple floors. Elevator users board and disembark the car when it is stopped at the floor level of each floor.

[0013] The elevator is controlled by a control device 100. The elevator operates by receiving power from an external AC power source 1. In this example, the AC power source 1 is a commercial power source that supplies three-phase AC power. Output terminals of each phase of the AC power source 1 are connected to respective input terminals of a power-on switch 2 of the control device 100.

[0014] Each power-on switch 2 is formed, for example, by a no-fuse breaker. The output terminal of each power-on switch 2 is connected to the input terminal of a contactor 3 of the control device 100. The output terminal of each contactor 3 is connected to each input terminal of a converter 4 of the control device 100. The converter 4 is formed, for example, by a three-phase diode bridge circuit. The high-potential side output terminal of the converter 4 is connected to the input terminal of a first DC bus 5. The low-potential side output terminal of the converter 4 is connected to the input terminal of a second DC bus 6.

[0015] A smoothing capacitor 7 of the control device 100 is connected between the first DC bus 5 and the second DC bus 6. The output terminal of the first DC bus 5 is connected to the high-potential input terminal of an inverter 8 of the control device 100. The output terminal of the second DC bus 6 is connected to the low-potential input terminal of the inverter 8 of the control device 100. The inverter 8 is configured, for example, by a two-level three-phase voltage-type full-bridge circuit. The inverter 8 includes switching elements (not shown). The switching elements of the inverter 8 are, for example, IGBTs (Insulated Gate Bipolar Transistors). The output terminals of the inverter 8 are connected to each input terminal of a hoisting machine motor 9. The hoisting machine motor 9 is a device that generates driving force to run the elevator car. The rotating shaft rotated by the hoisting machine motor 9 is connected to a drive sheave (not shown) around which, for example, a main rope is wound.

[0016] In an elevator configured as described above, contactor 3 is closed at startup. Closing contactor 3 supplies AC power from AC power source 1 to converter 4. Converter 4 converts the supplied AC power to DC power. The DC power converted and output by converter 4 is smoothed by smoothing capacitor 7. The smoothed DC power is input to inverter 8. Inverter 8 converts the input DC power into AC power. The AC power converted and output by inverter 8 is supplied to traction machine motor 9. Traction machine motor 9 uses the supplied AC power to rotate the rotating shaft and drive sheave. The rotation of the drive sheave moves the main rope, causing the car to travel up and down the hoistway.

[0017] On the other hand, depending on the relationship between the load on the car and the direction of travel of the car, the elevator may operate regeneratively. When the elevator operates regeneratively, the traction machine motor 9 functions as a generator. In other words, the traction machine motor 9 generates regenerative power. The control device 100 is equipped with a function to consume the regenerative power generated by the traction machine motor 9.

[0018] The control device 100 includes a regenerative resistor 10, a regenerative switching element 11, and a regenerative switching element gate drive circuit 12. The regenerative resistor 10 is, for example, a resistor that consumes power as Joule heat. The regenerative switching element 11 is an element that performs a switching operation to switch between allowing and not allowing current to flow in. The regenerative switching element 11 is, for example, an IGBT. The regenerative switching element gate drive circuit 12 is, for example, a gate driver that outputs a signal that drives the switching operation of the regenerative switching element 11. One end of the regenerative resistor 10 is connected to a first DC bus 5. The other end of the regenerative resistor 10 is connected to a collector terminal of the regenerative switching element 11. The emitter terminal of the regenerative switching element 11 is connected to a second DC bus 6. The output end of the regenerative switching element gate drive circuit 12 is connected to a gate terminal of the regenerative switching element 11.

[0019] The control device 100 includes a switching control unit 13, a first voltage monitoring unit 14, a threshold setting unit 15, a first life prediction unit 16, a second life prediction unit 17, a first temperature sensor 18, a second temperature sensor 19, and a fault judgment unit 20.

[0020] The switching control unit 13 is a unit that has a function of controlling the switching operation of the regenerative switching element 11. The output of the switching control unit 13 is connected to the input of the regenerative switching element gate drive circuit 12. The switching control unit 13 outputs a control signal for the switching operation to the regenerative switching element 11 via the regenerative switching element gate drive circuit 12.

[0021] The first voltage monitoring unit 14 is a part that has a function of detecting the voltage of the DC bus, i.e., the voltage between the first DC bus 5 and the second DC bus 6. The first voltage monitoring unit 14 is connected to the first DC bus 5 and the second DC bus 6. The output of the first voltage monitoring unit 14 is connected to the input of the switching control unit 13.

[0022] The threshold setting unit 15 is a part that has a function of setting a voltage threshold for the switching control unit 13. The voltage threshold is used to determine the timing of the switching operation of the regenerative switching element 11 in the switching control unit 13. The output of the threshold setting unit 15 is connected to the input of the switching control unit 13.

[0023] The switching control unit 13 controls the switching operation of the regenerative switching element 11 based on the relationship between the DC bus voltage value detected by the first voltage monitoring unit 14 and the voltage threshold value set by the threshold setting unit 15. In this example, the voltage threshold values ​​include a high-side voltage threshold value and a low-side voltage threshold value. The high-side voltage threshold value is set to a voltage value higher than the low-side voltage threshold value. One or both of the high-side voltage threshold value and the low-side voltage threshold value are set by the threshold setting unit 15. The high-side voltage threshold value or the low-side voltage threshold value may be a preset value. In this example, the high-side voltage threshold value is set to a specific fixed value that does not cause an overvoltage for devices such as the inverter 8 and the smoothing capacitor 7. When the DC bus voltage value detected by the first voltage monitoring unit 14 exceeds the high-side threshold value, the switching control unit 13 switches on the operation of the regenerative switching element 11 so that a current flows into the regenerative resistor 10. Furthermore, when the voltage value of the DC bus detected by the first voltage monitoring unit 14 falls below the low potential side threshold, the switching control unit 13 switches off the operation of the regenerative switching element 11 so that no current flows into the regenerative resistor 10. In this way, the switching control unit 13 performs hysteresis control.

[0024] When the elevator is in powered operation, the regenerative switching element 11 is always in an off state, preventing current from flowing into the regenerative resistor 10. On the other hand, if the converter 4 does not have a function for regenerating power to the AC power source 1, such as a diode converter, when the elevator is in regenerative operation, the regenerative power generated by the traction machine motor 9 is stored in the smoothing capacitor 7. At this time, the DC bus voltage rises. When the DC bus voltage rises and exceeds the high-potential threshold, the switching control unit 13 switches the regenerative switching element 11 to the on state. This forms a discharge circuit in which the regenerative resistor 10 is connected between the first DC bus 5 and the second DC bus 6. In the formed discharge circuit, the power stored in the smoothing capacitor 7 and the regenerative power are converted into Joule heat in the regenerative resistor 10 and consumed. At this time, the DC bus voltage drops. In this way, the on-off operation of the regenerative switching element 11 is repeated during regenerative operation of the elevator.

[0025] The first life prediction unit 16 is a part that has a function of predicting the remaining life of the regenerative switching element 11. The second life prediction unit 17 is a part that has a function of predicting the remaining life of the inverter 8.

[0026] The first temperature sensor 18 is disposed close to the regenerative switching element 11. The first temperature sensor 18 is mounted near the semiconductor chip of the regenerative switching element 11. The first temperature sensor 18 measures the temperature of the regenerative switching element 11. The measurement value of the first temperature sensor 18 is input to the first life prediction unit 16. The measurement value of the first temperature sensor 18 is used, for example, in the first life prediction unit 16 to predict the remaining life of the regenerative switching element 11.

[0027] The second temperature sensor 19 is disposed close to the inverter 8. The second temperature sensor 19 is mounted near a specific semiconductor chip mounted on the inverter 8. The semiconductor chip in question is, for example, a semiconductor chip selected from among the semiconductor chips mounted on the inverter 8 as one that will experience the largest temperature rise due to mounting. The semiconductor chip in question is, for example, a semiconductor chip of a switching element mounted on the inverter 8. The second temperature sensor 19 measures the temperature of the semiconductor chip in question. The measurement value of the second temperature sensor 19 is input to the second life prediction unit 17. The measurement value of the second temperature sensor 19 is used, for example, to predict the remaining life of the inverter 8 in the second life prediction unit 17. The remaining life of the inverter 8 corresponds, for example, to the remaining life of one of the semiconductor chips mounted on the inverter 8. Note that a plurality of second temperature sensors 19 may be mounted. In this case, each second temperature sensor 19 is mounted near a respective one of the specific semiconductor chips mounted on the inverter 8.

[0028] The threshold setting unit 15 sets the voltage threshold so that the remaining life of the inverter 8 predicted by the second life prediction unit 17 is longer than the remaining life of the regenerative switching element 11 predicted by the first life prediction unit 16. In this example, the threshold setting unit 15 selects one voltage value from multiple preset voltage values ​​based on the magnitude relationship between the remaining life of the inverter 8 and the remaining life of the regenerative switching element 11, and sets the selected voltage value as the low-potential-side voltage threshold. Here, the threshold setting unit 15 may compare the magnitude relationship between the remaining life of the inverter 8 and the remaining life of the regenerative switching element 11 taking into account a preset life margin. The life margin is set according to the accuracy of the remaining life prediction. This prevents the inverter 8 from reaching the end of its life before the regenerative switching element 11 due to poor remaining life prediction accuracy. The threshold setting unit 15 outputs the set voltage threshold to the switching control unit 13, thereby updating the voltage threshold used by the switching control unit 13.

[0029] The fault determination unit 20 is a part that has a function of determining whether an open fault has occurred in the regenerative switching element 11. The input of the fault determination unit 20 is connected to the output of the switching control unit 13. The fault determination unit 20 receives a control signal for the switching operation to the regenerative switching element 11 from the switching control unit 13. The input of the fault determination unit 20 is connected to the output of the first voltage monitoring unit 14. The fault determination unit 20 receives the voltage value of the DC bus detected by the first voltage monitoring unit 14.

[0030] The fault determination unit 20 determines whether an open fault has occurred in the regenerative switching element based on the detected value of the DC bus voltage after discharge, when a sufficient amount of time has passed since the smoothing capacitor 7 started to discharge. The fault determination unit 20 detects the start of discharge of the smoothing capacitor 7, for example, based on a control signal for switching operation from the switching control unit 13. The fault determination unit 20 determines whether a fault has occurred, for example, when the smoothing capacitor 7 is charged and the power supply to the smoothing capacitor 7 is cut off. The fault determination unit 20 determines whether a fault has occurred, for example, when the elevator is stopped and the contactor 3 is in an open state. The fault determination unit 20 may determine whether a fault has occurred when the elevator is in a pause mode in which operation is paused, or may determine whether a fault has occurred when the elevator is stopped in a diagnosis mode, for example, once a day.

[0031] Furthermore, the elevator may make an emergency stop due to a malfunction of the control device 100. In this case, if the car stops between floors, passengers inside the car may become trapped. The between-floor location may be, for example, the location between the floor levels of adjacent floors. Here, the elevator is controlled so that the remaining life of the inverter 8 is longer than the remaining life of the regenerative switching element 11, so the regenerative switching element 11 fails before the inverter 8. Therefore, when the elevator makes an emergency stop due to an open circuit failure of the regenerative switching element 11, the inverter 8 is not expected to have failed. Therefore, in the event of a trapped passenger, the control device 100 performs rescue operation in the powering direction if the failure determination unit 20 determines that an open circuit failure has occurred in the regenerative switching element 11. In rescue operation in the powering direction, the inverter 8 drives the hoist motor 9 to run the car in the powering direction and stop it at floor level. Rescue operation in the powering direction enables remote rescue, thereby realizing early rescue of trapped passengers.

[0032] Next, an example of the switching operation of the regenerative switching element 11 during regenerative operation of the elevator will be described with reference to FIG. 2A and 2B are diagrams illustrating an example of the switching operation of the regenerative switching element 11 during regenerative operation of the elevator according to the first embodiment. 2A and 2B, the horizontal axis represents time. In these graphs, the vertical axis represents voltage. In these graphs, a DC bus voltage value 21 is shown by a solid line. In these graphs, voltage thresholds 22, 23, and 24 are shown by dashed lines.

[0033] 2A shows an example in which the value obtained by subtracting a life margin from the remaining life of inverter 8 predicted by second life prediction unit 17 is longer than the remaining life of regenerative switching element 11 predicted by first life prediction unit 16. At this time, DC bus voltage value 21 transitions between high-potential-side voltage threshold 22 and first low-potential-side voltage threshold 23. Here, high-potential-side voltage threshold 22 is a preset fixed value. Furthermore, first low-potential-side voltage threshold 23 is a voltage value selected from multiple voltage values ​​and set by threshold setting unit 15 as the low-potential-side voltage threshold when the remaining life of inverter 8 minus the life margin becomes longer than the remaining life of regenerative switching element 11.

[0034] 2B shows an example in which the value obtained by subtracting the life margin from the remaining life of inverter 8 predicted by second life prediction unit 17 is shorter than the remaining life of regenerative switching element 11 predicted by first life prediction unit 16. At this time, DC bus voltage value 21 transitions between high-potential-side voltage threshold 22 and second low-potential-side voltage threshold 24. Here, second low-potential-side voltage threshold 24 is a voltage value selected from multiple voltage values ​​and set by threshold setting unit 15 as the low-potential-side voltage threshold when the remaining life of inverter 8 minus the life margin becomes shorter than the remaining life of regenerative switching element 11.

[0035] The second low-potential-side voltage threshold 24 is set higher than the first low-potential-side voltage threshold 23. That is, the hysteresis width, which is the difference in voltage between the high-potential-side voltage threshold and the low-potential-side voltage threshold, is wider in FIG. 2A than in FIG. 2B. Also, the hysteresis width is narrower in FIG. 2B than in FIG. 2A. Therefore, the regenerative switching element 11 operates at a lower frequency in FIG. 2A than in FIG. 2B. Also, the regenerative switching element 11 operates at a higher frequency in FIG. 2B than in FIG. 2A. Higher frequency switching in the regenerative switching element 11 results in greater switching loss and a shorter lifespan. On the other hand, lower frequency switching in the regenerative switching element 11 results in smaller switching loss and a longer lifespan. Therefore, controlling the hysteresis width adjusts the relationship between the remaining lifespan of the regenerative switching element 11 and the inverter 8.

[0036] Next, an example of the transition of the remaining life span of the inverter 8 and the regenerative switching element 11 and the setting of the voltage threshold will be described with reference to FIG. FIG. 3 is a diagram illustrating an example of the transition of the remaining life span of the inverter 8 and the regenerative switching element 11 in the elevator control device 100 according to the first embodiment, and the setting of the voltage threshold value.

[0037] In each of the graphs shown in Figure 3, the horizontal axis represents the number of years that have elapsed since the elevator was newly installed or since a part was replaced. When a part is replaced, the inverter 8 and the regenerative switching element 11 are replaced at the same time.

[0038] The upper graph in Fig. 3 shows the secular change of the voltage threshold set by threshold setting unit 15. In this graph, the vertical axis represents the set voltage threshold value. In this graph, a high-potential-side voltage threshold 22 and a low-potential-side voltage threshold 25 are shown. The low-potential-side voltage threshold 25 takes on either the value of a first low-potential-side voltage threshold 23 or a second low-potential-side voltage threshold 24.

[0039] 3 shows the aging of the remaining life 26 of the inverter 8 and the remaining life 27 of the regenerative switching element 11. The value obtained by subtracting the life margin 28 from the remaining life 26 of the inverter 8 is indicated by a dashed line 29.

[0040] Immediately after installation or component replacement, low potential side voltage threshold 25 is set to a higher first low potential side voltage threshold 23. First low potential side voltage threshold 23 is designed in advance so that remaining life 27 of regenerative switching element 11 is consumed more quickly than remaining life 26 of inverter 8. When remaining life 27 of regenerative switching element 11 is consumed over time and falls below value 29 obtained by subtracting remaining life margin 28 from remaining life 26 of inverter 8, threshold setting unit 15 sets low potential side voltage threshold 25 to a lower second low potential side voltage threshold 24. Second low potential side voltage threshold 24 is designed in advance so that remaining life 27 of regenerative switching element 11 is consumed more slowly than remaining life 26 of inverter 8. Thereafter, when the remaining life 27 of the regenerative switching element 11 exceeds the value 29 obtained by subtracting the life margin 28 from the remaining life 26 of the inverter 8, the threshold setting unit 15 resets the low potential side voltage threshold 25 to the first low potential side voltage threshold 23, which is a higher potential.

[0041] Next, an example of predicting the remaining life of the inverter 8 or the regenerative switching element 11 in the elevator control device 100 will be described with reference to FIG. 4A and 4B are diagrams illustrating an example of prediction of the remaining life of the inverter 8 or the regenerative switching element 11 in the elevator control device 100 according to the first embodiment. The first life prediction unit 16 and the second life prediction unit 17 predict the remaining life using, for example, Miner's rule based on temperature fluctuations as described below. Note that the first life prediction unit 16 and the second life prediction unit 17 may also employ the rainflow method as a method for predicting the remaining life from temperature fluctuations.

[0042] FIG. 4A shows the time variation of the measured value of the temperature sensor used to predict the remaining life. In the graph shown in FIG. 4A, the horizontal axis represents the passage of time. The vertical axis represents the measured temperature value. FIG. 4A shows the time variation of the measured value of the first temperature sensor 18 or the second temperature sensor 19. That is, FIG. 4A shows the temperature variation of a specific semiconductor chip equipped with a temperature sensor of the regenerative switching element 11 or the inverter 8. The temperature of the semiconductor chip fluctuates as the elevator operates. The first life prediction unit 16 and the second life prediction unit 17 calculate the life consumption corresponding to the temperature difference ΔT from the maximum value of the temperature fluctuation to the next minimum value for each temperature cycle and sequentially add up the calculated values ​​to calculate the cumulative life consumption. Here, the life consumption is a parameter expressed, for example, as a percentage. A life consumption of 100% indicates that the life has been reached. A life consumption of 50% indicates that half of the life has been consumed.

[0043] The first life prediction unit 16 calculates a predicted value of the remaining life of the regenerative switching element 11 using the cumulative life consumption calculated based on the temperature fluctuations of the first temperature sensor 18. The second life prediction unit 17 calculates a predicted value of the remaining life of the inverter 8 using the cumulative life consumption calculated based on the temperature fluctuations of the second temperature sensor 19. Here, the second life prediction unit 17 may calculate the remaining life of the semiconductor chip on which the second temperature sensor 19 is provided as the remaining life of the inverter 8. Furthermore, when multiple second temperature sensors 19 are provided, the second life prediction unit 17 may calculate the remaining life for each of multiple specific semiconductor chips on which the second temperature sensors 19 are provided. In this case, the second life prediction unit 17 may determine the shortest of the calculated remaining lives of the specific semiconductor chips as the remaining life of the inverter 8.

[0044] FIG. 4B is a diagram showing the relationship between the temperature difference ΔT and the corresponding lifetime consumption L. In the graph shown in FIG. 4B, the horizontal axis represents the temperature difference ΔT. In the graph, the vertical axis represents the lifetime consumption L. The relationship between the temperature difference ΔT and the lifetime consumption L is created in advance, for example, based on accelerated lifetime tests and calculations performed in advance. The relationship between the temperature difference ΔT and the lifetime consumption L is created, for example, for each specific semiconductor chip.

[0045] Next, an example of determining whether an open fault has occurred in the regenerative switching element 11 in the elevator control device 100 will be described with reference to FIG. 5A and 5B are diagrams illustrating an example of determining whether an open fault has occurred in a regenerative switching element in the elevator control device according to the first embodiment. 5A and 5B, the horizontal axis represents time. The vertical axis represents voltage. In these graphs, the voltage value 21 of the DC bus is indicated by a solid line.

[0046] 5A shows the change over time in the voltage value 21 of the DC bus when the power stored in the smoothing capacitor 7 is discharged in a normal case where the regenerative switching element 11 does not have an open circuit fault. The power stored in the smoothing capacitor 7 is discharged in a discharge circuit formed by the regenerative switching element 11 and the regenerative resistor 10.

[0047] The fault determination unit 20 detects switching of the regenerative switching element 11 from an OFF state to an ON state based on a control signal for the switching operation of the regenerative switching element 11 received from the switching control unit 13. The fault determination unit 20 determines whether the DC bus voltage value 21 detected by the first voltage monitoring unit 14 is below a discharge voltage threshold 31 after a discharge time 30 has elapsed since the start of discharging of the smoothing capacitor 7 due to switching of the regenerative switching element 11. Here, the discharge time 30 is set in advance as a time sufficient for the time required for discharging the smoothing capacitor 7. The discharge voltage threshold 31 is set in advance as a voltage sufficient for determining whether the smoothing capacitor 7 has discharged. When the DC bus voltage value 21 is below the discharge voltage threshold 31, the fault determination unit 20 determines that the smoothing capacitor 7 has discharged normally and that the regenerative switching element 11 has not reached an open fault.

[0048] 5B shows the change over time in the DC bus voltage value 21 when the regenerative switching element 11 is switched from the OFF state to the ON state, as in the case of FIG. 5A, in the case where the regenerative switching element 11 has an open-circuit fault. In this case, a discharge circuit is not formed due to the open-circuit fault in the regenerative switching element 11, and discharging of the smoothing capacitor 7 does not start. At this time, the DC bus voltage 21 remains above the discharge voltage threshold 31 even after the discharge time 30 has elapsed. Therefore, the fault determination unit 20 determines that the regenerative switching element 11 has experienced an open-circuit fault when the DC bus voltage value 21 remains above the discharge voltage threshold 31 after the discharge time 30 has elapsed since the regenerative switching element 11 was switched.

[0049] As described above, the elevator control device 100 according to the first embodiment includes the inverter 8, the smoothing capacitor 7, the regenerative resistor 10, the regenerative switching element 11, the first voltage monitoring unit 14, the threshold setting unit 15, the switching control unit 13, the first life prediction unit 16, and the second life prediction unit 17. The inverter 8 drives the hoisting machine motor 9 that drives the elevator car. The smoothing capacitor 7 stabilizes the voltage of the DC bus connected to the inverter 8. The regenerative resistor 10 is connected to the DC bus. The regenerative resistor 10 consumes regenerative power generated by the hoisting machine motor 9 during regenerative operation of the elevator. The regenerative switching element 11 switches between allowing and not allowing current to flow into the regenerative resistor 10. The first voltage monitoring unit 14 detects the voltage of the DC bus. The threshold setting unit 15 sets a voltage threshold that determines the timing of the switching operation of the regenerative switching element 11. The switching control unit 13 controls the switching operation of the regenerative switching element 11 based on the relationship between the voltage value detected by the first voltage monitoring unit 14 and the voltage threshold set by the threshold setting unit 15. The first life prediction unit 16 predicts the remaining life of the regenerative switching element 11. The second life prediction unit 17 predicts the remaining life of the inverter 8. The threshold setting unit 15 sets the voltage threshold so that the remaining life of the inverter 8 predicted by the second life prediction unit 17 is longer than the remaining life of the regenerative switching element 11 predicted by the first life prediction unit 16. Moreover, the elevator control method according to the first embodiment includes a first prediction step, a second prediction step, and a threshold setting step. The first prediction step is a step of predicting the remaining life of the regenerative switching element 11. The second prediction step is a step of predicting the remaining life of the inverter 8. The threshold setting step is a step of setting a voltage threshold so that the remaining life of the inverter 8 predicted in the second prediction step is longer than the remaining life of the regenerative switching element 11 predicted in the first prediction step.

[0050] With this configuration, the elevator is controlled so that the remaining life of inverter 8 is longer than the remaining life of regenerative switching element 11, so regenerative switching element 11 will fail before inverter 8. Therefore, when the elevator makes an emergency stop due to an open circuit failure of regenerative switching element 11, it is expected that inverter 8 will not have failed. Since an emergency stop due to a failure of inverter 8 is less likely to occur, it is less likely that passengers will be trapped in a way that makes rescue operation by running the car in the power running direction impossible.

[0051] The control device 100 also includes a first temperature sensor 18. The first temperature sensor 18 is disposed in proximity to the regenerative switching element 11. The first life prediction unit 16 predicts the remaining life of the regenerative switching element 11 based on the temperature fluctuation measured by the first temperature sensor 18. The control device 100 also includes a second temperature sensor 19. The second temperature sensor 19 is disposed in proximity to a semiconductor chip such as a switching element of the inverter 8. The second life prediction unit 17 predicts the remaining life of the inverter 8 based on the temperature fluctuation measured by the second temperature sensor 19.

[0052] With this configuration, the remaining life is predicted based on the measured value of the temperature fluctuation of the element, so the predicted remaining life value becomes more accurate, which makes it less likely that a passenger will be trapped in a train that cannot be rescued by running the car in the power running direction.

[0053] The control device 100 also includes a fault determination unit 20. The fault determination unit 20 determines that an open fault has occurred in the regenerative switching element 11. When the car is stopped at a position between floors, the fault determination unit 20 may determine that an open fault has occurred in the regenerative switching element 11. In this case, the inverter 8 drives the hoist motor 9 so as to perform a rescue operation in which the car travels in the powering direction and stops at floor level.

[0054] With this configuration, even if a person is trapped when the life of a component of the control device 100 has expired, rescue operation in the power running direction is possible, making remote rescue easier than rescue by releasing the brakes and realizing earlier rescue in the event of a person being trapped.

[0055] Furthermore, the fault determination unit 20 determines whether an open fault has occurred in the regenerative switching element 11 when the smoothing capacitor 7 is charged and the power supply to the smoothing capacitor 7 is cut off. Under these circumstances, the fault determination unit 20 determines whether an open fault has occurred in the regenerative switching element 11 based on the voltage value detected by the first voltage monitoring unit 14 after the regenerative switching element 11 performs a switching operation to allow current to flow into the regenerative resistor 10.

[0056] With this configuration, the fault determination unit 20 determines whether an open fault has occurred in the regenerative switching element 11 based on the actual detected value of the voltage of the DC bus, thereby making it possible to more accurately determine whether a fault has occurred.

[0057] Furthermore, when the voltage value detected by the first voltage monitoring unit 14 exceeds the high-potential-side voltage threshold, the switching control unit 13 switches the operation of the regenerative switching element 11 so that current flows into the regenerative resistor 10. When the voltage value detected by the first voltage monitoring unit 14 falls below the low-potential-side voltage threshold, the switching control unit 13 switches the operation of the regenerative switching element 11 so that current does not flow into the regenerative resistor 10. The threshold setting unit 15 sets the voltage threshold when the value obtained by subtracting a preset life margin from the remaining life of the inverter 8 predicted by the second life prediction unit 17 becomes shorter than the remaining life of the regenerative switching element 11 predicted by the first life prediction unit 16. At this time, the threshold setting unit 15 sets at least one of the high-potential-side voltage threshold and the low-potential-side voltage threshold as the voltage threshold so as to reduce the difference between the high-potential-side voltage threshold and the low-potential-side voltage threshold.

[0058] With this configuration, by switching the switching operation between high-frequency operation and low-frequency operation, the relationship between the remaining life of the regenerative switching element 11 and the remaining life of the inverter 8 can be adjusted more easily.

[0059] Note that some or all of the information processing functions of the control device 100, such as the threshold setting unit 15, the first life prediction unit 16, the second life prediction unit 17, and the failure determination unit 20, may be mounted on one or more servers. Some or all of the servers may be located in remote locations from the elevator and communicate with each other via a communication network such as the Internet or a telephone network. Some or all of the information processing functions of the control device 100 may be realized by processing or storage resources on a cloud service.

[0060] Furthermore, the remaining life of the regenerative switching element 11 and the remaining life of the inverter 8 may be predicted outside the control device 100. The threshold setting unit 15 may accept manual setting of the voltage threshold by, for example, a maintenance person.

[0061] Next, an example of the hardware configuration of the control device 100 will be described with reference to FIG. FIG. 6 is a hardware configuration diagram of the main part of the control device 100 according to the first embodiment.

[0062] Each function of the control device 100 may be realized by a processing circuit. The processing circuit includes at least one processor 200 a and at least one memory 200 b. The processing circuit may include at least one dedicated hardware 300 in addition to or in place of the processor 200 a and the memory 200 b.

[0063] When the processing circuit includes a processor 200a and a memory 200b, each function of the control device 100 is realized by software, firmware, or a combination of software and firmware. At least one of the software and firmware is written as a program. The program is stored in the memory 200b. The processor 200a realizes each function of the control device 100 by reading and executing the program stored in the memory 200b.

[0064] The processor 200a is also referred to as a CPU (Central Processing Unit), processing device, arithmetic device, microprocessor, microcomputer, or DSP. The memory 200b is configured by, for example, non-volatile or volatile semiconductor memory such as RAM, ROM, flash memory, EPROM, or EEPROM.

[0065] Where the processing circuitry comprises dedicated hardware 300, the processing circuitry may be implemented, for example, as a single circuit, multiple circuits, a programmed processor, parallel programmed processors, an ASIC, an FPGA, or a combination thereof.

[0066] Each function of the control device 100 can be realized by a processing circuit. Alternatively, each function of the control device 100 can be realized collectively by a processing circuit. Some of the functions of the control device 100 may be realized by dedicated hardware 300, and the other parts may be realized by software or firmware. In this way, the processing circuit realizes each function of the control device 100 by dedicated hardware 300, software, firmware, or a combination of these.

[0067] Embodiment 2 In the second embodiment, differences from the example disclosed in the first embodiment will be described in particular detail. For features not described in the second embodiment, any of the features of the example disclosed in the first embodiment may be adopted.

[0068] FIG. 7 is a configuration diagram of an elevator control device according to the second embodiment.

[0069] The control device 100 includes an inverter gate drive circuit 32 and an inverter control unit 33. The inverter gate drive circuit 32 is, for example, a gate driver that outputs signals that drive the switching operations of each switching element mounted in the inverter 8. Each output terminal of the inverter gate drive circuit 32 is connected to the gate terminal of the corresponding switching element mounted in the inverter 8. The inverter control unit 33 is a part that has a function of controlling the operation of the inverter 8, such as the switching operations of each switching element mounted in the inverter 8. An output of the inverter control unit 33 is connected to an input of the inverter gate drive circuit 32. The inverter control unit 33 outputs a control signal for the switching operation to each switching element mounted in the inverter 8 via the inverter gate drive circuit 32.

[0070] The control device 100 includes a first temperature predicting unit 34, a second temperature predicting unit 35, a reference temperature sensor 36, and a second voltage monitoring unit 37.

[0071] The first temperature prediction unit 34 is a unit equipped with a function for predicting temperature fluctuations of the regenerative switching element 11. The second temperature prediction unit 35 is a unit equipped with a function for predicting temperature fluctuations of a specific semiconductor chip mounted on the inverter 8. This semiconductor chip is, for example, a semiconductor chip selected from among the semiconductor chips mounted on the inverter 8 as one that will experience the largest temperature rise due to packaging. This semiconductor chip is, for example, a semiconductor chip of a switching element mounted on the inverter 8. Each of the first temperature prediction unit 34 and the second temperature prediction unit 35 receives a control signal from the inverter control unit 33 to the inverter 8. The first temperature prediction unit 34 receives information on the voltage threshold set by the threshold setting unit 15. The prediction value of the first temperature prediction unit 34 is input to the first life prediction unit 16. The prediction value of the first temperature prediction unit 34 is used by the first life prediction unit 16 to predict the remaining life of the regenerative switching element 11. The first life prediction unit 16 predicts the remaining life of the regenerative switching element 11 based on the predicted value of the temperature fluctuation by the first temperature prediction unit 34, similar to the prediction of the remaining life based on the measured value of the temperature fluctuation. The predicted value by the second temperature prediction unit 35 is input to the second life prediction unit 17. The predicted value by the second temperature prediction unit 35 is used to predict the remaining life of the inverter 8 in the second life prediction unit 17. The second life prediction unit 17 predicts the remaining life of the inverter 8 based on the predicted value of the temperature fluctuation by the second temperature prediction unit 35, similar to the prediction of the remaining life based on the measured value of the temperature fluctuation.

[0072] The reference temperature sensor 36 is disposed on the heat dissipation path of the regenerative switching element 11 or a specific semiconductor chip mounted on the inverter 8. The reference temperature sensor 36 may be disposed on the heat dissipation path of both the regenerative switching element 11 and the specific semiconductor chip mounted on the inverter 8. The reference temperature sensor 36 is mounted, for example, on the base plate of a heat dissipation fin (not shown) to which the inverter 8 and the regenerative switching element 11 are connected. The reference temperature sensor 36 measures a reference temperature. The measurement value of the reference temperature sensor 36 is input to each of the first temperature prediction unit 34 and the second temperature prediction unit 35. The reference temperature is used to predict temperature fluctuations by the first temperature prediction unit 34 and the second temperature prediction unit 35. Note that the reference temperature sensor 36 may be mounted separately for the regenerative switching element 11 and the inverter 8.

[0073] The first temperature prediction unit 34 receives input of a current command value and a voltage command value from the inverter control unit 33. The first temperature prediction unit 34 receives input of information on the voltage threshold set by the threshold setting unit 15. The first temperature prediction unit 34 predicts temperature fluctuations based on a preset temperature estimation model. The temperature estimation model held by the first temperature prediction unit 34 is, for example, a model that calculates the temperature of the regenerative switching element 11 from a reference temperature, a current command value, a voltage command value, and a low-potential-side voltage threshold. The temperature estimation model is, for example, composed of a thermal circuit.

[0074] The second temperature prediction unit 35 receives inputs of a current command value and a voltage command value from the inverter control unit 33. The second temperature prediction unit 35 predicts temperature fluctuations based on a preset temperature estimation model. The temperature estimation model held by the second temperature prediction unit 35 is, for example, a model that calculates the temperature of a semiconductor chip such as a switching element mounted on the inverter 8 from a reference temperature, a current command value, and a voltage command value. The temperature estimation model is, for example, formed by a thermal circuit.

[0075] The second voltage monitoring unit 37 is a part that has a function of detecting the voltage on the secondary side of the regenerative switching element 11. The second voltage monitoring unit 37 is connected to the collector terminal and the emitter terminal of the regenerative switching element 11. The second voltage monitoring unit 37 monitors the collector-emitter voltage of the regenerative switching element 11. The output of the second voltage monitoring unit 37 is connected to the input of the fault determination unit 20.

[0076] The fault determination unit 20 determines the occurrence of an open fault in the regenerative switching element 11 based on the logical consistency between the control signal for the switching operation to the regenerative switching element 11 received from the switching control unit 13 and the secondary side voltage of the regenerative switching element 11 received from the second voltage monitoring unit 37. For example, when the fault determination unit 20 receives an ON command or OFF command to the regenerative switching element 11 from the switching control unit 13, it determines whether the measured value of the secondary side voltage of the regenerative switching element 11 is behaving correctly without any logical inconsistency. When there is a logical inconsistency in the measured value of the secondary side voltage of the regenerative switching element 11, the fault determination unit 20 determines that the regenerative switching element 11 has reached an open fault.

[0077] As described above, the elevator control device 100 according to the second embodiment includes the reference temperature sensor 36. The reference temperature sensor 36 is arranged on the heat dissipation path of semiconductor chips such as the regenerative switching element 11 and the switching elements of the inverter 8. The reference temperature sensor 36 measures a reference temperature. The control device 100 includes a first temperature prediction unit 34. The first temperature prediction unit 34 predicts temperature fluctuations of the regenerative switching element 11 based on the measurement value of the reference temperature sensor 36 and a preset temperature estimation model. The first life prediction unit 16 predicts the remaining life of the regenerative switching element 11 based on the temperature fluctuations predicted by the first temperature prediction unit 34. The control device 100 also includes a second temperature prediction unit 35. The second temperature prediction unit 35 predicts temperature fluctuations in semiconductor chips such as switching elements of the inverter 8 based on the measurement values ​​of the reference temperature sensor 36 and a preset temperature estimation model. The second life prediction unit 17 predicts the remaining life of the inverter 8 based on the temperature fluctuations predicted by the second temperature prediction unit 35.

[0078] With this configuration, the temperature fluctuation of the element is predicted based on the measured value of the reference temperature, so that the remaining life can be predicted even when a temperature sensor or the like is not provided near the element.

[0079] The control device 100 also includes a second voltage monitoring unit 37. The second voltage monitoring unit 37 detects the voltage on the secondary side of the regenerative switching element 11. The fault determination unit 20 determines whether an open fault has occurred in the regenerative switching element 11 based on the consistency between the control signal output from the switching control unit 13 to the regenerative switching element 11 and the voltage detected by the second voltage monitoring unit 37.

[0080] With this configuration, the fault determination unit 20 determines the occurrence of an open fault in the regenerative switching element 11 based on the actual detected value of the consistency between the input and operation of the regenerative switching element 11, thereby making the determination of the occurrence of a fault more accurate. [Industrial Applicability]

[0081] The control device and control method according to the present disclosure can be applied to elevators. [Explanation of symbols]

[0082] 1 AC power supply, 2 power-on switch, 3 contactor, 4 converter, 5 first DC bus, 6 second DC bus, 7 smoothing capacitor, 8 inverter, 9 traction machine motor, 10 regenerative resistor, 11 regenerative switching element, 12 regenerative switching element gate drive circuit, 13 switching control unit, 14 first voltage monitoring unit, 15 threshold setting unit, 16 first life prediction unit, 17 second life prediction unit, 18 first temperature sensor, 19 second temperature sensor, 20 fault determination unit, 21 DC bus voltage value, 22 high potential side voltage threshold, 23 first low potential side voltage threshold, 24 second low potential side voltage threshold, 25 low potential side voltage threshold, 26 remaining life of inverter, 27 remaining life of regenerative switching element, 28 life margin, 29 Value obtained by subtracting a life margin from the remaining life of the inverter, 30 discharge time, 31 discharge voltage threshold, 32 inverter gate drive circuit, 33 inverter control unit, 34 first temperature prediction unit, 35 second temperature prediction unit, 36 reference temperature sensor, 37 second voltage monitoring unit, 100 control device, 200a processor, 200b memory, 300 dedicated hardware

Claims

1. an inverter that drives a traction motor that runs the elevator car; a smoothing capacitor for stabilizing the voltage of a DC bus connected to the inverter; a regenerative resistor connected to the DC bus and consuming regenerative power generated by the hoisting machine motor during regenerative operation of the elevator; a regenerative switching element that switches whether or not a current flows into the regenerative resistor; a first voltage monitoring unit that detects a voltage of the DC bus; a threshold setting unit that sets a voltage threshold that determines the timing of a switching operation of the regenerative switching element; a switching control unit that controls a switching operation of the regenerative switching element based on a relationship between the voltage value detected by the first voltage monitoring unit and the voltage threshold value set by the threshold value setting unit; a first life prediction unit that predicts a remaining life of the regenerative switching element; a second life prediction unit that predicts a remaining life of the inverter; Equipped with the threshold setting unit sets the voltage threshold so that the remaining life of the inverter predicted by the second life prediction unit is longer than the remaining life of the regenerative switching element predicted by the first life prediction unit. Control device.

2. a first temperature sensor disposed adjacent to the regenerative switching element; Equipped with the first life prediction unit predicts a remaining life of the regenerative switching element based on a temperature fluctuation measured by the first temperature sensor; The control device according to claim 1 .

3. a second temperature sensor disposed adjacent to a switching element of the inverter; Equipped with the second life prediction unit predicts a remaining life of the inverter based on a temperature fluctuation measured by the second temperature sensor. The control device according to claim 1 .

4. a reference temperature sensor disposed on a heat dissipation path of the regenerative switching element and configured to measure a reference temperature; a first temperature prediction unit that predicts a temperature fluctuation of the regenerative switching element based on a measurement value of the reference temperature sensor and a preset temperature estimation model; Equipped with the first life prediction unit predicts a remaining life of the regenerative switching element based on the temperature fluctuation predicted by the first temperature prediction unit; The control device according to claim 1 .

5. a reference temperature sensor disposed on a heat dissipation path of a switching element of the inverter and configured to measure a reference temperature; a second temperature prediction unit that predicts a temperature fluctuation of a switching element of the inverter based on a measurement value of the reference temperature sensor and a preset temperature estimation model; Equipped with the second life prediction unit predicts a remaining life of the inverter based on the temperature fluctuation predicted by the second temperature prediction unit. The control device according to claim 1 .

6. a fault determination unit that determines whether an open fault has occurred in the regenerative switching element; Equipped with When the failure determination unit determines that an open failure has occurred in the regenerative switching element while the car is stopped at a position between floors, the inverter drives the hoist motor to perform a rescue operation in which the car travels in a powering direction and stops at floor level. The control device according to any one of claims 1 to 5.

7. When the regenerative switching element performs a switching operation so that a current flows into the regenerative resistor under a condition in which the smoothing capacitor is charged and power supply to the smoothing capacitor is cut off, the failure determination unit determines the occurrence of an open failure in the regenerative switching element based on a voltage value detected by the first voltage monitoring unit after the switching operation. The control device according to claim 6.

8. a second voltage monitoring unit that detects a voltage on the secondary side of the regenerative switching element; Equipped with the failure determination unit determines the occurrence of an open failure in the regenerative switching element based on consistency between a control signal output from the switching control unit to the regenerative switching element and a voltage detected by the second voltage monitoring unit. The control device according to claim 6.

9. the switching control unit switches the operation of the regenerative switching element so that a current flows into the regenerative resistor when the voltage value detected by the first voltage monitoring unit exceeds a high-potential-side voltage threshold, and switches the operation of the regenerative switching element so that a current does not flow into the regenerative resistor when the voltage value detected by the first voltage monitoring unit falls below a low-potential-side voltage threshold; the threshold setting unit sets at least one of the high potential side voltage threshold and the low potential side voltage threshold as the voltage threshold so as to reduce a difference between the high potential side voltage threshold and the low potential side voltage threshold when a value obtained by subtracting a preset life margin from the remaining life of the inverter predicted by the second life prediction unit becomes shorter than the remaining life of the regenerative switching element predicted by the first life prediction unit. The control device according to any one of claims 1 to 5.

10. an inverter that drives a hoisting machine motor that runs the car; a smoothing capacitor for stabilizing the voltage of a DC bus connected to the inverter; a regenerative resistor connected to the DC bus and consuming regenerative power generated by the hoisting machine motor during regenerative operation; a regenerative switching element that switches whether or not a current flows into the regenerative resistor; a first voltage monitoring unit that detects a voltage of the DC bus; a switching control unit that controls a switching operation of the regenerative switching element based on a relationship between the voltage value detected by the first voltage monitoring unit and a voltage threshold that determines a timing of a switching operation of the regenerative switching element; An elevator control method comprising: a first prediction step of predicting a remaining life of the regenerative switching element; a second prediction step of predicting a remaining life of the inverter; a threshold setting step of setting the voltage threshold so that the remaining life of the inverter predicted in the second prediction step is longer than the remaining life of the regenerative switching element predicted in the first prediction step; A control method comprising:

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