CN118510713A

CN118510713A - Control device for elevator

Info

Publication number: CN118510713A
Application number: CN202280088110.0A
Authority: CN
Inventors: 大塚康司; 和田山久广
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2022-01-19
Filing date: 2022-01-19
Publication date: 2024-08-16
Also published as: JP7505653B2; JPWO2023139690A1; WO2023139690A1

Abstract

Provided is an elevator control device capable of applying dynamic braking to an electric motor by a simple structure. A control device for an elevator controls a synchronous motor for rotationally driving a sheave, comprising: an inverter unit that supplies an ac voltage of a plurality of phases obtained by converting a dc voltage to the motor; and a control unit that controls the inverter unit, the inverter unit including: an upper arm configured by a plurality of switching elements corresponding to the plurality of phases, respectively; and a lower arm configured by a plurality of switching elements corresponding to the plurality of switching elements, wherein the control unit turns off all switching elements belonging to one of the upper arm and the lower arm and turns on all switching elements belonging to the other of the upper arm and the lower arm when performing a rescue operation in which the car is moved by a torque acting on the sheave due to a difference between a weight of the car and a weight of the counterweight.

Description

Control device for elevator

Technical Field

The present disclosure relates to a control device for an elevator.

Background

Patent document 1 discloses an elevator apparatus. The elevator apparatus is provided with a dynamic brake (dynamic brake) circuit. The dynamic braking circuit is connected to a power supply line for the motor. When the rescue operation switch is operated, the motor and the dynamic braking circuit form a closed circuit. In this case, the rescue operation in which the car is driven by the unbalanced torque acting due to the difference between the car weight and the counterweight weight can be performed in a state where the dynamic brake acts on the motor.

Prior art literature

Patent literature

Patent document 1: japanese patent application laid-open No. 2012-184043

Disclosure of Invention

Problems to be solved by the invention

However, in the elevator apparatus described in patent document 1, the dynamic braking circuit is provided separately from the inverter circuit. Therefore, it is necessary to install an apparatus for enabling dynamic braking.

The present disclosure has been made to solve the above-described problems. The purpose of the present disclosure is to provide a control device for an elevator, which is capable of applying dynamic braking to a motor with a simple structure.

Means for solving the problems

The control device of the elevator controls a synchronous motor for rotationally driving a rope pulley around which a main rope suspending a car and a counterweight is wound, wherein the control device of the elevator comprises: an inverter unit that supplies, to the motor, ac voltages of a plurality of phases obtained by converting a dc voltage; and a control unit that controls the inverter unit, the inverter unit including: an upper arm configured by a plurality of switching elements corresponding to the plurality of phases, respectively; and a lower arm configured by a plurality of switching elements corresponding to the plurality of switching elements, wherein the control unit turns off all switching elements belonging to one of the upper arm and the lower arm and turns on all switching elements belonging to the other of the upper arm and the lower arm when performing a rescue operation in which the car is moved by a torque acting on the sheave due to a difference between a weight of the car and a weight of the counterweight.

Effects of the invention

According to the present disclosure, when performing the rescue operation, the control unit turns off all the switching elements belonging to one of the upper arm and the lower arm, and turns on all the switching elements belonging to the other of the upper arm and the lower arm. Therefore, dynamic braking can be applied to the motor by a simple structure.

Drawings

Fig. 1 is a schematic diagram of an elevator system to which the control device of the elevator according to embodiment 1 is applied.

Fig. 2 is a diagram showing a circuit of a main part of the control device of the elevator according to embodiment 1.

Fig. 3 is a diagram showing an outline of the on operation performed by the control device of the elevator according to embodiment 1.

Fig. 4 is a diagram showing an outline of the on operation performed by the control device of the elevator according to embodiment 1.

Fig. 5 is a diagram showing the values of the duty ratios set for the control device of the elevator according to embodiment 1.

Fig. 6 is a flowchart for explaining an outline of the operation of the control device of the elevator according to embodiment 1.

Fig. 7 is a flowchart for explaining an outline of the operation of the control device of the elevator according to embodiment 1.

Fig. 8 is a flowchart for explaining an outline of the operation of the control device of the elevator according to embodiment 1.

Fig. 9 is a hardware configuration diagram of the control device for an elevator according to embodiment 1.

Fig. 10 is a diagram showing an outline of the on operation performed by the control device of the elevator according to embodiment 2.

Fig. 11 is a flowchart for explaining an outline of the operation of the control device of the elevator according to embodiment 2.

Fig. 12 is a schematic view of an elevator system to which the control device of the elevator according to embodiment 3 is applied.

Fig. 13 is a flowchart for explaining an outline of the operation of the control device of the elevator according to embodiment 3.

Fig. 14 is a flowchart for explaining an outline of the operation of the control device of the elevator according to embodiment 3.

Detailed Description

The manner in which the present disclosure is practiced is described with reference to the accompanying drawings. In the drawings, the same or corresponding portions are denoted by the same reference numerals. Repeated description of this portion is appropriately simplified or omitted.

Embodiment 1.

In the elevator system of fig. 1, a hoistway 1 penetrates floors of a building, not shown. A machine room, not shown, is provided directly above the hoistway 1. The plurality of landing stations 2 are provided on each floor of the building. Fig. 1 shows one of a plurality of landing stations 2.

The motor 3 is provided in a machine room. The motor 3 is a synchronous motor. The motor 3 has a rotor with permanent magnets. The motor 3 has a rotary shaft body that rotates in synchronization with the rotor. The sheave 4 is provided in the machine room. The shaft of the sheave 4 is fixed coaxially with the rotary shaft of the motor 3. Two brakes 5 are provided adjacent to the sheave 4. The two brakes 5 are capable of braking the sheave 4. In the elevator system, the number of the brakes 5 may be one or three or more instead of two.

The main rope 6 is wound around the sheave 4. The car 7 is provided inside the hoistway 1. The car 7 is suspended from one side of the main rope 6. The counterweight 8 is provided inside the hoistway 1. The counterweight 8 is suspended from the other side of the main ropes 6. Namely, the car 7 and the counterweight 8 are suspended in a bucket by means of the sheave 4 and the main ropes 6. The weight of the counterweight 8 is a preset weight. For example, the weight of the counterweight 8 is equal to the sum of the weight of the car 7 and 50% of the rated load bearing weight of the car 7.

The weighing device 9 is arranged under the floor of the car 7. The weighing device 9 is capable of measuring the weight inside the car 7. The door zone sensor 10 is provided outside the car 7. A plurality of door zone plates 11 are provided inside the hoistway 1. The plurality of door zone plates 11 are provided at height positions corresponding to the plurality of landing stations 2. Fig. 1 shows one of a plurality of door zone plates 11.

The control device 12 is arranged in the machine room. An ac voltage is supplied from a commercial power source E to the control device 12. The control device 12 can control the elevator system as a whole. The control device 12 includes a converter unit 13, an inverter unit 14, and a control unit 15.

The converter section 13 includes a converter circuit. The converter unit 13 is electrically connected to the commercial power source E. The converter unit 13 converts an ac voltage from the commercial power source E into a dc voltage. The converter unit 13 outputs a dc voltage from the positive bus P and the negative bus N. In the present embodiment, the converter section 13 outputs a dc voltage of the voltage value V _dc.

The inverter unit 14 is electrically connected to the converter unit 13 via the bus bar P and the bus bar N. The inverter unit 14 is a full-bridge inverter circuit. The inverter unit 14 converts the dc voltage into ac voltages of a plurality of phases in the bridge circuit 16. In the present embodiment, the bridge circuit 16 outputs ac voltages of U-phase, V-phase, and W-phase. The bridge circuit 16 may convert a dc voltage into an ac voltage having a number of phases other than three.

The bridge circuit 16 comprises three bridge arms 17. The three arms 17 correspond to the U phase, V phase, and W, respectively. The three bridge arms 17 are connected across the positive bus line P and the negative bus line N, respectively. The three bridge arms 17 each include an upper arm switch 18 and a lower arm switch 19. That is, the bridge circuit 16 includes three upper arm switches 18 and three lower arm switches 19.

Three upper arm switches 18 are connected to the bus bar P on the positive side. The three upper arm switches 18 correspond to the U phase, V phase, and W, respectively. The upper arm switch 18 includes a semiconductor switching element as a switching element. For example, the upper arm switch 18 includes an IGBT (Insulated Gate Bipolar Transistor ) and a diode for feedback. The set of three upper arm switches 18 functions as an upper arm 20 of the bridge circuit 16.

Three lower arm switches 19 are connected to the bus bar N on the negative side. The three lower arm switches 19 are connected in series with the corresponding three upper arm switches 18 between the bus bar P and the bus bar N, respectively. The three lower arm switches 19 correspond to the U phase, the V phase, and the W phase, respectively. The lower arm switch 19 includes a semiconductor switching element as a switching element. For example, the lower arm switch 19 includes an IGBT (Insulated Gate Bipolar Transistor ) and a diode for feedback. The group of three lower arm switches 19 functions as the lower arm 21 of the bridge circuit 16.

Three wires 22 electrically connect the motor 3 to the three arms 17, respectively. Three wires 22 are connected between the upper arm switch 18 and the lower arm switch 19 of the corresponding phase.

The control unit 15 is electrically connected to the two brakes 5, the weighing device 9, and the door zone sensor 10. The control unit 15 controls the operation of the inverter unit 14. Specifically, the control unit 15 generates a switching command to turn on or off the three upper arm switches 18 and the three lower arm switches 19 independently, and transmits the switching command to the inverter unit 14. The control unit 15 may perform control to directly turn on or off the three upper arm switches 18 and the three lower arm switches 19 without generating a switching command.

When the elevator system is operating normally, the control device 12 controls the operation of the motor 3 by supplying electric power. Specifically, the converter unit 13 converts the ac voltage of the commercial power source E into a dc voltage, and supplies the dc voltage to the inverter unit 14. The inverter unit 14 converts the dc voltage into three-phase ac voltage. At this time, the control device 12 controls the ac voltage converted by the inverter unit 14 by controlling the three upper arm switches 18 and the three lower arm switches 19 independently. The inverter unit 14 supplies an ac voltage to the motor 3.

The motor 3 generates torque in the rotary shaft based on the ac voltage from the inverter unit 14. The motor 3 rotates a sheave 4 coaxially connected to the rotating shaft. That is, the control device 12 controls the rotational drive of the motor 3 and the sheave 4. The main rope 6 moves following the rotation of the sheave 4. The car 7 and the counterweight 8 rise and fall in opposite directions to each other following the movement of the main ropes 6.

When the weighing device 9 is in normal operation, information indicating the weight of the inside of the car 7 as the weight of the passenger is transmitted to the control device 12 at a predetermined cycle. In the case where the car 7 has approached the destination landing 2, the control device 12 controls the driving of the motor 3 and the driving of the two brakes 5 to decelerate the car 7. For example, the control device 12 controls the motor 3 to reduce the value of the torque generated at the sheave 4. The control device 12 sends a command to the two brakes 5 to generate braking force to the sheave 4. The two brakes 5 respectively generate frictional forces for stopping the sheave 4, thereby decelerating the car 7.

Then, the door zone sensor 10 detects the door zone plate 11 corresponding to the landing 2. The door zone sensor 10 sends a signal to the control device 12 indicating that the door zone plate 11 is detected. The control device 12 controls the driving of the motor 3 and the driving of the two brakes 5 based on the signal from the door zone sensor 10 to stop the car 7 at the landing position. In this way, the car 7 conveys the passenger to the landing 2 which is the landing of the target floor. For example, when the car 7 stops at the landing 2, the motor 3 does not generate torque on the sheave 4. The two brakes 5 hold the sheave 4 stationary.

In an elevator system, when a specific failure occurs, a rescue operation using a difference between the weight of the car 7 and the weight of the counterweight 8 is sometimes performed. For example, the specific failure refers to a failure in which the rotation of the motor 3 should not be controlled by applying a voltage to the motor 3. Specifically, for example, if a device for measuring the rotation amount of the rotary shaft of the motor 3 fails, the position and speed of the car 7 cannot be controlled, and thus rescue operation is performed. In the rescue operation, the car 7 stopped between the two landings 2 is moved to any one of the landings 2. Then, the door of the car 7 is opened so that the passenger can get off the car 7.

An unbalanced torque due to the difference between the weight of the car 7 and the weight of the counterweight 8 acts on the sheave 4. For example, in the case where the weight inside the car 7 as the weight of the load is not 50% of the weight of the load at a predetermined amount, the weight of the car 7 including the car 7 main body and the load of the car 7 is lighter than the weight of the counterweight 8. In this case, an unbalanced torque in the direction in which the car 7 rises acts on the sheave 4. The unbalanced torque also acts on the motor 3 via the rotating shaft body. On the other hand, when the weight inside the car 7 exceeds 50% of the rated load weight, the weight of the car 7 is heavier than the weight of the counterweight 8. In this case, unbalanced torque in the direction in which the car 7 descends acts on the sheave 4 and the motor 3.

The weight of the counterweight 8 may be set to be equal to the sum of the weight of the car 7 and a value other than 50% such as 40% and 45% of the rated load bearing weight of the car 7. In this case, the same unbalanced torque also acts on the sheave 4 and the motor 3.

When the car 7 moves during the rescue operation, the two brakes 5 release the braked sheave 4 in response to a command from the control device 12. The sheave 4 is rotationally driven by unbalanced torque. The car 7 moves following the rotation of the sheave 4. At this time, the control device 12 causes the motor 3 to dynamically brake by shorting the closed circuit including the motor 3 and the inverter unit 14. The dynamic braking torque acts in a direction to brake the rotational movement of the sheave 4. The car 7 moves at a predetermined speed at which the passengers in the car 7 are not disturbed or uncomfortable due to the unbalanced torque or the torque caused by the dynamic braking as much as possible.

In the rescue operation, when the car 7 has approached any one of the landings 2, the door zone sensor 10 detects the corresponding door zone plate 11. The door zone sensor 10 sends a detection signal of the door zone plate 11 to the control device 12. The control device 12 drives the two brakes 5 based on the detection signal to stop the car 7 at the landing 2.

Next, control for dynamically braking the motor 3 will be described with reference to fig. 2.

Fig. 2 shows a state of the inverter section 14 in a case where dynamic braking of the motor 3 occurs. The plurality of switching elements included in the upper arm 20 are in an on state. The plurality of switching elements included in the lower arm 21 are in an off state. In addition, a closed circuit may be formed between the motor 3 and the switching element included in the lower arm 21, instead of the upper arm 20. That is, all switching elements included in one of the upper arm 20 and the lower arm 21 are turned off, and all switching elements included in the other of the upper arm 20 and the lower arm 21 are turned on. In fig. 2, the motor 3 and the inverter section 14 constitute a closed circuit shown by solid lines. That is, the motor 3 and the inverter unit 14 are short-circuited in all circuits of the U-phase, V-phase, and W-phase.

When the rotary shaft of the motor 3 rotates in this state, dynamic braking occurs in the motor 3. Specifically, when the rotary shaft body rotates, the rotor of the permanent magnet rotates in the vicinity of the coil inside the motor 3. According to fleming's right hand rule, an induced electromotive force is generated in the coil. That is, the motor 3 functions as a generator, and an induced current flows in a closed circuit formed by the motor 3 and the inverter unit 14. The induced current does not flow through a circuit shown by a broken line, that is, a circuit including a plurality of switching elements included in the lower arm 21 and the motor 3. The induced current is returned to the motor 3 through the inverter unit 14. When the induced current returned to the motor 3 flows through the coil, a rotational resistance in a direction opposite to the rotational direction of the rotor acts on the rotor according to the fleming's left hand rule. That is, dynamic braking based on the rotational resistance is generated in the motor 3.

The magnitude of the rotational resistance against the rotational speed of the rotor is determined by the number of coil windings of the motor 3, the magnetic force of the rotor, and other characteristics inherent to the motor 3. Therefore, in the state of fig. 2, the magnitude of the torque generated by dynamic braking depends on the rotational speed of the rotor. The greater the rotational speed of the rotor, the greater the torque of the dynamic brake.

The control unit 15 turns off all the switching elements included in the lower arm 21 of the inverter unit 14, and turns on all the switching elements included in the upper arm 20, thereby controlling the dynamic braking torque generated in the motor 3. At this time, as the on operation, the control unit 15 intermittently turns on all the switching elements included in the upper arm. That is, as the on operation, the control unit 15 alternately switches on and off all the switching elements included in the upper arm. The control unit 15 controls torque applied by dynamic braking by performing on operation.

In addition, turning on all the switching elements included in the upper arm 20 is also referred to as "turning on the upper arm 20". Turning off all switching elements included in the upper arm 20 is also referred to as "turning off the upper arm 20". The same applies to the lower arm 21.

Next, the on operation in the control device 12 will be described with reference to fig. 3.

Fig. 3 (a) is a graph showing the net torque value acting on the sheave 4 during the on operation at each time. Fig. 3 (B) is a graph showing the state of turning on or off the upper arm 20 of the UVW phase at a certain time. Fig. 3 (C) is a graph showing the state of turning on or off the lower arm 21 of the UVW phase at a certain time.

As shown in fig. 3 (C), the lower arm 21 is in the OFF (OFF) state at any time. As shown in fig. 3B, as the ON operation, the upper arm 20 is intermittently turned ON, that is, alternately switches between an ON (ON) state and an OFF (OFF) state. Specifically, the control unit 15 turns off all the switching elements included in the upper arm 20 in the period from time t ₀ to t ₁. Then, the control unit 15 turns on the upper arm 20 at time t ₁, and maintains the upper arm 20 on for a period of time from time t ₁ to t ₂. Then, the control section 15 turns off the upper arm 20 at time t ₂, and maintains the upper arm 20 off for a period of time from time t ₂ to t ₃. The control unit 15 repeatedly performs the same operation. At this time, the control unit 15 controls the on operation of the upper arm 20 so as to have a predetermined duty ratio. The duty ratio is a ratio of the on time, which is a total value of the times of the on states, to a total value of the overall times. The total value of the overall time is the sum of the on-time and the off-time, which is the total value of the times in the off-state. Fig. 3 (B) shows a case where the duty ratio is 50%.

In this case, as shown in fig. 3 (a), the net torque value applied to the sheave 4 changes depending on the time. Specifically, a net torque value corresponding to the unbalanced torque acts on the sheave 4 in the period from time t ₀ to t ₁. In the period from time t ₁ to t ₂, torque due to dynamic braking of the motor 3 acts on the sheave 4. Thus, the net torque value acting on the sheave 4 is reduced by the amount of torque value due to dynamic braking over the period of time t ₁ to t ₂ compared to the torque value in the period of time t ₀ to t ₁. Then, in the period from time t ₂ to t ₃, a net torque value corresponding to the unbalanced torque acts on the sheave 4.

In fig. 3 (a), the net average torque value T _ave in a prescribed period including the period of time T ₀ to T ₄ is shown by a broken line. The average torque value T _ave is smaller than the torque value corresponding to the unbalanced torque.

Next, the duty ratio will be described with reference to fig. 4.

As shown in fig. 4 (a) and (B), the control unit 15 controls the average torque value T _ave by changing the duty ratio in the on operation. For example, the control unit 15 controls the duty ratio of the on operation so that the average torque value T _ave becomes a constant value. At this time, the control unit 15 sets a duty ratio corresponding to the magnitude of the unbalanced torque. The control unit 15 controls the duty ratio so that the maximum value of the moving speed of the car 7 during the rescue operation becomes a constant value regardless of the magnitude of the unbalanced torque.

Fig. 4 (a) shows the on operation in the case where the torque value of the unbalanced torque is large. For example, the torque value of the unbalanced torque in fig. 4 (a) is larger than that of the unbalanced torque in fig. 3. In this case, the duty ratio is set to a value greater than 50%. The period of time t ₁ to t ₂, which is the time of the on state, is longer than the period of time t ₂ to t ₃, which is the time of the off state. That is, the torque due to dynamic braking acts for a longer period of time than in the case of the duty ratio of 50%. Therefore, the difference between the average torque value T _ave in the case of (a) of fig. 4 and the torque value of the unbalanced torque is larger than in the case of fig. 3. As a result, for example, the average torque value T _ave in the case of fig. 4 (a) is the same value as the average torque value T _ave in the case of fig. 3.

Fig. 4 (B) shows the on operation in the case where the torque value of the unbalanced torque is small. For example, the torque value of the unbalanced torque in (B) of fig. 4 is smaller than that of the unbalanced torque in fig. 3. In this case, the duty ratio is set to a value less than 50%. The period of time t ₁ to t ₂, which is the time of the on state, is shorter than the period of time t ₂ to t ₃, which is the time of the off state. That is, the time in which the torque due to dynamic braking acts is shorter than in the case of the duty ratio of 50%. Therefore, the difference between the average torque value T _ave and the torque value of the unbalanced torque in the case of (a) of fig. 4 is smaller than that in the case of fig. 3. As a result, for example, the average torque value T _ave in the case of fig. 4 (B) is the same value as the average torque value T _ave in the case of fig. 3 and the case of fig. 4.

Next, a relationship between duty ratios with respect to the weight inside the car 7 will be described with reference to fig. 5.

Fig. 5 shows an example of the correspondence relationship of the duty ratio with respect to the weight inside the car 7. The vertical axis is the duty cycle. The horizontal axis represents the weight inside the car 7. The control unit 15 stores information indicating the correspondence relationship. For example, the control unit 15 performs a learning operation to create and store information indicating the correspondence relationship.

The torque value of the imbalance torque corresponds to the difference between the weight of the car 7 and the weight of the counterweight 8. Here, the weight of the counterweight 8 is a fixed value set in advance. That is, the torque value of the unbalanced torque varies according to the weight inside the car 7. Specifically, the absolute value of the torque value varies with respect to the absolute value of the difference between the weight inside the car 7 and the rated load-bearing weight of the car 7. Therefore, the control unit 15 determines a duty ratio corresponding to the weight inside the car 7 based on the information indicating the weight inside the car 7 from the weighing device 9.

Fig. 5 shows correspondence under conditions a and B shown by line segments a and broken lines B. The difference between the condition a and the condition B is a difference in the inherent characteristics of the motor 3. The magnitude of the rotational resistance with respect to the rotational speed of the motor 3 of the condition a is smaller than the magnitude of the rotational resistance with respect to the rotational speed of the motor 3 of the condition B.

In the correspondence between either condition a and condition B, the duty ratio becomes smaller as the weight in the car 7 becomes closer to 50% of the rated load weight. The line segment shown in the correspondence relationship has a shape folded back with a value of 50% of the rated load.

When the weight of the counterweight 8 corresponds to a value other than 50% such as 40% and 45% of the rated load weight of the car 7, the correspondence relationship shown in fig. 5 is a shape folded back at 40% and 45% respectively. Further, the graph showing the correspondence relationship may be a graph showing a higher order function instead of a straight line.

Next, an operation performed when rescue operation is performed will be described with reference to fig. 6.

The operation of the flowchart shown in fig. 6 is started when control device 12 determines that the rescue operation is to be performed.

In step S001, the control device 12 acquires information indicating the weight inside the car 7 from the weighing device 9. The control device 12 detects the weight inside the car 7.

Then, the operation of step S002 is performed. In step S002, the control device 12 selects a duty ratio corresponding to the weight inside the car 7 based on the information of the correspondence relation stored in advance. The control device 12 determines the selected duty ratio as the duty ratio used in the rescue operation.

Then, the control device 12 ends the operation of the flowchart. For example, control device 12 then starts the rescue operation.

Next, the operation of the control device 12 during the rescue operation will be described with reference to fig. 7.

The actions of the flowchart shown in fig. 7 begin after the actions shown in the flowchart of fig. 6.

In step S101, the control device 12 releases the two brakes 5 from stopping the sheave 4. The control device 12 turns off the lower arm 21 and turns on the upper arm 20. Therefore, the car 7 travels by the action of unbalanced torque and the action of dynamic braking. In addition, in the case where both the brakes 5 have released the sheave 4 in step S101, the control device 12 maintains a state where both the brakes 5 have released the sheave 4.

Then, the operation of step S102 is performed. In step S102, the control device 12 determines whether a gate area is detected. Specifically, when receiving the detection signal of the door zone plate 11 from the door zone sensor 10, the control device 12 determines that the door zone is detected.

If it is not determined in step S102 that the door zone is detected, control device 12 performs the operations of step S101 and beyond.

When it is determined in step S102 that the gate area is detected, the operation of step S103 is performed. In step S103, the control device 12 stops the two brakes 5 against the sheave 4. Thus, the car 7 stops at the door zone.

Then, the control device 12 ends the operation of the flowchart.

In the rescue operation, it is difficult to finely adjust the speed of the car 7 by dynamic braking during the running of the car 7. As shown in the flowchart, when the car 7 has reached the door zone as the stop position, the control device 12 stops the car 7 by the two brakes 5.

Fig. 7 shows an operation of an example in which only one horizontal height (level) of the door zone is set as the stop position. If the door zone level is divided into a plurality of door zones, the vehicle may travel again toward the next door zone level after step S103. In this case, the operations of step S101 and subsequent steps may be repeated.

Specifically, for example, consider a case where the horizontal height of the door zone is divided into 0mm, 5mm, 20mm, 50mm from the stop position. In this case, the control device 12 first detects a gate area of a horizontal height of 50mm in step S102. The control device 12 stops by performing the operation of step S103. Then, by the operation of step S101, the car 7 travels toward the door zone at a horizontal height of 20 mm. Thereafter, the control device 12 repeats the operations of steps S101 to S103 until the gate areas of the horizontal heights of 20mm, 5mm, and 0mm are detected, respectively. When a gate area of a horizontal height of 0mm is detected, the control device 12 ends the operation of the flowchart. For example, the control device 12 then opens the door of the car 7.

Next, the duty learning operation performed by the control device 12 will be described with reference to fig. 8.

The control device 12 performs learning operation to create a relationship of the duty ratio with respect to the weight inside the car 7 as a correspondence relationship shown in fig. 5. The learning operation is performed in a normal state of the motor 3 or the like as a driving device of the elevator system. Specifically, the learning operation is performed when the elevator system is installed, when the elevator system is tested in an elevator test tower, when the elevator system is tested using a motor reference device, or the like. After the learning operation, the control device 12 stores information indicating the correspondence created by the learning operation.

In the learning operation when the elevator system is installed or when a test is performed in an elevator test tower, a weight having a known weight is mounted on the car. Then, the car is driven in a state where the brake is released, that is, in the same manner as in the rescue operation. At this time, the duty ratio and the speed of the car are measured. Based on the measured information, a duty ratio at which the car travels at a predetermined speed is determined when the weight inside the car is a certain value. The predetermined speed is a speed at which passengers in the car do not feel uncomfortable.

In the learning operation in the test using the motor reference device, a torque corresponding to the unbalanced torque is applied to the evaluation motor by the load motor. In this state, the evaluation motor generates dynamic braking while the duty ratio is changed. At this time, the duty ratio and the rotational speed corresponding to the speed of the car are measured. Based on the measured information, a duty ratio at which the car travels at a predetermined speed is determined when the weight inside the car is a certain value.

The flowchart shown in fig. 8 shows an outline of the learning operation of the control device 12 when the elevator system is installed or when a test is performed in the elevator test tower. The operations in the flowchart may be performed by a test device other than the control device 12.

In a state where a weight of a certain weight is loaded on the car 7, the operation of the flowchart is started.

In step S201, the control device 12 detects the weight inside the car 7 based on the information from the weighing device 9. In this case, the control device 12 may detect the weight of the inside of the car 7 by inputting the weight of the weight loaded on the car 7, instead of the information from the weighing device 9.

Then, the operation of step S202 is performed. In step S201, the control device 12 sets the duty ratio to a predetermined value. For example, the control device 12 sets the duty ratio to 100%. In this example, 100% of the duty cycle that functions to the maximum is used as a predetermined value in order to ensure safety. However, the control device 12 may set the duty ratio to another value.

Then, the operation of step S203 is performed. The control device 12 releases both brakes 5. In this case, the car 7 travels by the action of unbalanced torque and the action of dynamic braking.

Then, the operation of step S204 is performed. The control device 12 monitors the speed of the car 7. The control device 12 determines whether or not the speed of the car 7 is a predetermined speed. Here, the control device 12 uses the speed of the car 7 when the car 7 is stable in a certain speed range as the speed of the car 7 in the determination.

In step S204, the speed of the car 7 may be measured by any method. For example, the control device 12 may calculate the speed of the car 7 from the rotational speed of the motor 3 calculated from the measured value of the angle detector provided to the motor 3. The control device 12 may monitor the speed of the car 7 based on information from a speed limiter attached to the car 7.

When it is determined in step S204 that the speed of the car 7 is not the predetermined speed, the operation of step S205 is performed. In step S205, the control device 12 changes the duty ratio to another value to adjust the duty ratio. Then, the control device 12 performs the operations of step S204 and thereafter.

When it is determined in step S204 that the speed of the car 7 is a predetermined speed, the operation of step S206 is performed. In step S206, the control device 12 stores the current duty ratio in association with the weight inside the car 7. Then, the control device 12 ends the operation of the flowchart.

Then, the weight of the weight loaded on the car 7 is changed, and the operation of the flowchart is repeated.

After repeating the operations of the flowchart a plurality of times, the control device 12 creates information indicating the correspondence relationship between the duty ratio and the weight inside the car 7. In this case, the information of the weight inside the car 7 may not be information measured under all weight conditions. For example, the control device 12 may create information representing the correspondence relationship by linear approximation by several measurement points. For example, when the rated load weight is 50%, the control device 12 may calculate the correspondence relationship between 50% and 100% by weight based on the weight condition that the weight in the car 7 is 0% to 50%. In this case, the correspondence of 50% to 100% by weight is complemented to a shape in which the correspondence of 0% to 50% is folded back. This is because, when the weight of the car 7 is 0% of the rated load weight and when it is 100% of the rated load weight, the absolute value of the unbalance torque acting on the sheave 4 is the same and the direction of the action is different.

According to embodiment 1 described above, the control device 12 includes the inverter unit 14 and the control unit 15. During the rescue operation, the control device 12 turns off one of the upper arm 20 and the lower arm 21, and turns on the other of the upper arm 20 and the lower arm 21. The switching element included in the arm that performs the conduction operation forms a closed circuit with the motor 3. Thus, dynamic braking acts on the motor 3. That is, according to the control device 12 of the present embodiment, it is not necessary to add a device for applying dynamic braking to the structure of the existing elevator system. As a result, dynamic braking can be applied to the motor 3 by a simple structure.

Further, as the on operation, the control device 12 alternately switches on and off all the switching elements included in the arm. When all the switching elements are turned on, dynamic braking occurs in the motor 3. When all switching elements are off, dynamic braking is not generated in the motor 3. Since the torque caused by dynamic braking intermittently acts on the sheave 4, the average torque value acting on the sheave 4 is smaller than in the case where dynamic braking always acts. Therefore, the speed of the car 7 during the rescue operation can be increased as compared with the case where dynamic braking is always applied.

The control device 12 controls the duty ratio during the on operation. It is assumed that the maximum value of dynamic braking generated at the motor 3 is constant with a constant duty ratio. On the other hand, the value of the unbalance torque varies according to the weight inside the car 7. That is, the maximum speed of the car 7 during the rescue operation may vary depending on the weight inside the car 7. If the speed is too high, the passenger in the car 7 may feel uncomfortable and uncomfortable. In addition, when the speed is too slow, it takes time until the passenger gets out of the car 7. The control device 12 of the present embodiment can control the speed of the car 7 during the rescue operation by controlling the duty ratio in accordance with the weight of the car 7. As a result, the car 7 can be driven at a constant speed regardless of the weight of the car 7.

Further, the control device 12 stores information of the correspondence relationship. The control device 12 determines the duty ratio in the rescue operation based on the information measured by the weighing device 9 and the information of the correspondence relation. Therefore, the control device 12 can appropriately control the duty ratio according to the weight of the car 7.

The control device 12 performs learning operation to create correspondence information. Therefore, for example, at the time of elevator installation, the control device 12 can create information of the correspondence relationship.

In addition, during the rescue operation, the control device 12 performs control to stop the car 7 at the stop position based on the signal from the door zone sensor 10. Conventionally, rescue operation is sometimes performed manually by an operator who is dispatched to an elevator system. The control device 12 of the present embodiment can automatically perform rescue operation.

In addition, the following structure may be adopted: the motor 3 and the sheave 4 are not directly connected by the rotary shaft body, but indirectly connected by a gear provided therebetween.

The elevator system may be a roping elevator system provided with a car 7 and a counterweight 8, and may not be 1 shown in fig. 1:1 roping mode, but 2:1 roping, etc. Furthermore, the elevator system may be in such a way that no machine room is provided.

The weighing device 9 may be provided at a position other than the under floor of the car 7 as long as the weight inside the car 7 can be measured.

In addition, when the car 7 travels in step S101 in fig. 7, the control device 12 may intermittently travel the car 7 by setting a time interval for releasing the two brakes 5. In this case, for example, when the door zone is not detected during the period in which the two brakes 5 are released for 5 seconds, the control device 12 may cause the two brakes 5 to brake the sheave 4. Then, the control device 12 may repeat the operations after step S101 to divide the traveling operation into a plurality of times to travel the car 7. Therefore, the maximum speed of the car 7 during the rescue operation can be suppressed. As a result, the rescue operation can be performed more safely.

Next, an example of hardware constituting the control device 12 will be described with reference to fig. 9.

The functions of the control device 12 may be implemented by a processing circuit. For example, the processing circuit is provided with at least one processor 100a and at least one memory 100b. For example, the processing circuit is provided with at least one dedicated hardware 200.

In the case of a processing circuit provided with at least one processor 100a and at least one memory 100b, the respective functions of the control device 12 are implemented by software, firmware, or a combination of software and firmware. At least one of the software and the firmware is described as a program. At least one of the software and firmware is stored in at least one memory 100 b. The at least one processor 100a implements the functions of the control device 12 by reading and executing programs stored in the at least one memory 100 b. The at least one processor 100a is also referred to as a central processing unit, a processing unit, an arithmetic unit, a microprocessor, a microcomputer, a DSP. For example, the at least one Memory 100b is a nonvolatile or volatile semiconductor Memory such as RAM (Random Access Memory: random access Memory), ROM (Read Only Memory), flash Memory, EPROM (Erasable Programmable Read Only Memory: erasable programmable Read Only Memory), EEPROM (ELECTRICALLY ERASABLE PROGRAMMABLE READ ONLY MEMORY: electrically erasable programmable Read Only Memory), magnetic disk, floppy disk, optical disk, CD (compact disc), mini disc (mini disc), DVD (DIGITAL VERSATILE DISK: digital versatile disc), or the like.

In the case of a processing Circuit with at least one dedicated hardware 200, the processing Circuit is implemented, for example, by a single Circuit, a composite Circuit, a programmed processor, a parallel programmed processor, an ASIC (Application SPECIFIC INTEGRATED Circuit), an FPGA (Field Programmable GATE ARRAY field programmable gate array), or a combination thereof. For example, each function of the control device 12 is realized by a processing circuit. For example, the functions of the control device 12 are unified by a processing circuit.

With respect to the functions of the control device 12, one part may be implemented by dedicated hardware 200, and the other part may be implemented by software or firmware. For example, the functions of the converter unit 13 may be realized by a processing circuit that is dedicated hardware 200, and the functions other than the functions of the converter unit 13 may be realized by at least one processor 100a reading out and executing a program stored in at least one memory 100 b.

Thus, the processing circuitry implements the functions of the control device 12 via hardware 200, software, firmware, or a combination thereof.

Embodiment 2.

Fig. 10 is a diagram showing an outline of the on operation performed by the control device of the elevator according to embodiment 2. The same or corresponding parts as those of embodiment 1 are denoted by the same reference numerals. The description of this portion is omitted.

In embodiment 2, the control device 12 alternately switches the arms that perform the on operation from among the upper arm 20 and the lower arm 21. Specifically, the control unit 15 turns off one of the upper arm 20 and the lower arm 21 and turns on the other, and then turns off the other of the upper arm 20 and the lower arm and turns on the other. Then, the control unit 15 turns off one of the upper arm 20 and the lower arm 21 and turns on the other. In this way, the control unit 15 alternately switches the arms that perform the on operation. The control unit 15 turns off the arm that is not on. In this case, the number of times the arm is turned on in the on operation may be any number as long as it is at least one.

Fig. 10 shows a case where the number of times the arm is turned on, that is, the cycle is one time in the on operation. The control unit 15 turns off the lower arm 21 and turns on the upper arm 20 in a period from time t ₀ to t ₂. Then, the control unit 15 turns off the upper arm 20 and turns on the lower arm 21 in a period from time t ₂ to t ₄. Then, the control unit 15 turns off the lower arm 21 and turns on the upper arm 20 in a period from time t ₄ to t ₆.

In this case, in the motor 3, dynamic braking is effected in the period of time t ₁ to t ₂, in the period of time t ₃ to t ₄, and in the period of time t ₅ to t ₆. Therefore, the net average torque value T _ave becomes a value shown by a broken line. The control unit 15 thus controls the average torque value T _ave.

Since the switching elements through which the induced current flows are alternately switched, the thermal load generated by the on operation is generated in the upper arm 20 and the lower arm 21 without bias in both arms.

Next, an operation performed when the rescue operation is performed will be described with reference to fig. 11.

The operation of the flowchart shown in fig. 11 is started when control device 12 determines that the rescue operation is to be performed.

In step S301, the control device 12 acquires information from the weighing device 9, and detects the weight inside the car 7.

Then, the operation of step S302 is performed. In step S302, the control device 12 selects a duty ratio corresponding to the weight inside the car 7 based on the information of the correspondence relation stored in advance, and determines the duty ratio to be used in the rescue operation.

Then, the operation of step S303 is performed. In step S303, as an initial arm, the control device 12 selects one of the upper arm 20 and the lower arm 21 as the arm that first performs the on operation. The arm that first performs the on operation may be any arm.

Then, the operation of step S304 is performed. In step S304, the control device 12 releases the two brakes 5 from stopping the sheave 4. The control device 12 turns on the arm selected in step S303, and turns off the other arm. Therefore, the car 7 starts traveling by the action of the unbalanced torque and the action of the dynamic brake.

Then, the operation of step S305 is performed. In step S305, the control unit 15 of the control device 12 determines whether or not the arm in the on operation has been on for a predetermined period.

When it is determined in step S305 that the arm is not conducting for a predetermined period, the operation of step S305 is repeated. That is, the control device 12 causes the same arm to continue the on operation.

When it is determined in step S305 that the arm on operation has been performed for a predetermined period, the operation of step S306 is performed. In step S306, the control device 12 determines whether or not the car 7 has finished traveling. Specifically, when the control device 12 receives a detection signal of the stopping position from the door zone sensor 10 and the brake 5 is stopping the sheave 4, it determines that the car 7 has finished traveling.

When it is determined in step S306 that the car 7 is not traveling, the operation of step S307 is performed. In step S307, the control unit 15 of the control device 12 switches the arm in the on operation to the other arm. Then, the control device 12 performs the operations of step S305 and thereafter.

When it is determined in step S306 that the car 7 has finished traveling, the control device 12 ends the operation of the flowchart.

According to embodiment 2 described above, control device 12 switches the arm that performs the on operation during the rescue operation. Therefore, when dynamic braking is generated, the upper arm 20 and the lower arm 21 can be alternately caused to generate heat. That is, the bias of heat generated in the upper arm 20 and the lower arm 21 can be suppressed. In the case where a thermal load is excessively applied to the switching element, the switching element may malfunction. According to the control device 12, the configuration of the inverter unit 14 can be protected during the rescue operation.

Embodiment 3.

Fig. 12 is a schematic view of an elevator system to which the control device of the elevator according to embodiment 3 is applied. The same or corresponding parts as those of embodiment 1 or 2 are denoted by the same reference numerals. The description of this portion is omitted.

As shown in fig. 12, in embodiment 3, the control device 12 includes a failure detection unit 30.

As fault detection of the inverter section 14, the fault detection section 30 detects a fault of the switching element of the inverter section 14. The failure detection unit 30 determines a failure location of the inverter unit 14. That is, the inverter unit 14 identifies the switching element in which the failure has occurred. For example, the inverter unit 14 detects which of the upper arm 20 and the lower arm 21 the switching element having failed belongs to. The fault detection unit 30 detects whether the switching element in which the fault has occurred is an on fault or an off fault. The conduction failure refers to a failure in which the switching element is stuck on the conduction side and is always in the conduction state. The off failure refers to a failure in which the switching element is stuck on the off side and is always in the off state.

In addition, the method of detecting the failure of the switching element by the failure detection section 30 may be applied to various methods. For example, the fault detection unit 30 may detect a fault of the switching element based on a detection result of an overcurrent detection circuit, not shown, provided in the inverter unit 14. For example, the fault detection unit 30 may estimate and detect a fault of the switching element based on information indicating a voltage and a current supplied to the motor 3 when the motor 3 is driven.

When detecting a failure of the inverter unit 14, the failure detection unit 30 transmits information indicating a failure location of the inverter unit 14 to the control unit 15. For example, the fault detection unit 30 detects whether or not the inverter unit 14 has failed during normal operation of the elevator system.

When receiving the information indicating the failure location from the failure detection unit 30, the control unit 15 shifts to the rescue operation. In the rescue operation, the control unit 15 controls the inverter unit 14 in correspondence with a failure portion of the inverter unit 14. Specifically, the control unit 15 determines the arm that is turned off and the arm that is turned on among the upper arm 20 and the lower arm 21, in correspondence with the failure location.

Next, a rescue operation when a switching element has a conduction failure will be described with reference to fig. 13.

The flowchart shown in fig. 13 is control performed by the control device 12 when the failure detection unit 30 detects an on failure of the switching element. When detecting a failure of the switching element, the control device 12 starts the operation of the flowchart.

In step S401, the fault detection unit 30 of the control device 12 detects a fault location of the switching element as a conduction fault location, and a case where the fault is a conduction fault. The failure detection unit 30 transmits the detected information to the control unit 15.

Then, the operation of step S402 is performed. In step S402, the control unit 15 of the control device 12 determines whether or not the switching element in which the failure has occurred belongs to the upper arm 20, based on the information from the failure detection unit 30.

In step S402, when it is determined that the switching element having failed belongs to the upper arm, the operation of step S403 is performed. In step S403, the control unit 15 transmits a command to turn off the lower arm 21 and turn on the upper arm 20 to the inverter unit 14. The inverter unit 14 operates according to the instruction. In addition, in the on operation, the on and off of the switching element in which the on failure does not occur is switched.

Then, when the rescue operation is completed, control device 12 ends the operation of the flowchart.

When it is determined in step S402 that the switching element having failed does not belong to the upper arm, the operation of step S404 is performed. In this case, the switching element in which the conduction failure occurs belongs to the lower arm 21. In step S404, the control unit 15 transmits a command to turn off the upper arm 20 and turn on the lower arm 21 to the inverter unit 14. The inverter unit 14 operates according to the instruction. In addition, in the on operation, the on and off of the switching element in which the on failure does not occur is switched.

Next, a rescue operation when a switching element has an off failure will be described with reference to fig. 14.

The flowchart shown in fig. 14 is control performed by the control device 12 when the failure detection unit 30 detects an off failure of the switching element. When detecting a failure of the switching element, the control device 12 starts the operation of the flowchart.

In step S501, the fault detection unit 30 of the control device 12 detects a fault location of the switching element as a cut-off fault location, and a case where the fault is a cut-off fault. The failure detection unit 30 transmits the detected information to the control unit 15.

Then, the operation of step S502 is performed. In step S502, the control unit 15 of the control device 12 determines whether or not the switching element in which the failure has occurred belongs to the upper arm 20, based on the information from the failure detection unit 30.

When it is determined in step S502 that the switching element having failed belongs to the upper arm, the operation of step S503 is performed. In step S503, the control unit 15 transmits a command to turn off the upper arm 20 and turn on the lower arm 21 to the inverter unit 14. The inverter unit 14 operates according to the instruction. That is, the control device 12 performs the on operation of the lower arm 21 that can be turned on.

When it is determined in step S502 that the switching element having failed does not belong to the upper arm, the operation of step S504 is performed. In this case, the switching element in which the off failure occurs belongs to the lower arm 21. In step S504, the control unit 15 transmits a command to turn off the lower arm 21 and turn on the upper arm 20 to the inverter unit 14. The inverter unit 14 operates according to the instruction. That is, control device 12 performs the on operation of upper arm 20 that can be turned on.

Then, when the rescue operation is completed, the control device 12 ends the operation of the flowchart

According to embodiment 3 described above, the control device 12 includes the failure detection unit 30. Therefore, control device 12 can perform rescue operation according to the failure location of the switching element.

Further, the fault detection unit 30 of the control device 12 detects an on fault. During the rescue operation, the control device 12 causes the arm including the switching element in which the conduction failure has occurred to perform the conduction operation. Therefore, even if an on-failure occurs, dynamic braking of the motor 3 can be generated.

Further, the failure detection unit 30 of the control device 12 detects a cutoff failure. During the rescue operation, the control device 12 turns on the arm that does not include the switching element in which the off failure has occurred. Therefore, even if a cutoff failure occurs, rescue operation can be performed. In this case, the motor 3 can be efficiently braked.

Industrial applicability

As described above, the control device of the present disclosure can be used in an elevator system.

Description of the reference numerals

1: A hoistway; 2: a landing; 3: a motor; 4: a rope pulley; 5: a brake; 6: a main rope; 7: a car; 8: a counterweight; 9: a weighing device; 10: a door zone sensor; 11: a door zone plate; 12: a control device; 13: a converter section; 14: an inverter section; 15: a control unit; 16: a bridge circuit; 17: bridge arms; 18: an upper arm switch; 19: a lower arm switch; 20: an upper arm; 21: a lower arm; 22: a wire; 30: a fault detection unit; 100a: a processor; 100b: a memory; 200: hardware.

Claims

1. An elevator control device for controlling a synchronous motor for rotationally driving a sheave on which a main rope suspending a car and a counterweight is suspended, the elevator control device comprising:

An inverter unit that supplies, to the motor, ac voltages of a plurality of phases obtained by converting a dc voltage; and

A control unit for controlling the inverter unit,

The inverter section includes:

An upper arm configured by a plurality of switching elements corresponding to the plurality of phases, respectively; and

A lower arm composed of a plurality of switching elements corresponding to the plurality of phases respectively,

The control unit turns off all switching elements belonging to one of the upper arm and the lower arm and turns on all switching elements belonging to the other of the upper arm and the lower arm when performing a rescue operation in which the car is moved by an unbalanced torque acting on the sheave due to a difference between the weight of the car and the weight of the counterweight.

2. The control device of an elevator according to claim 1, wherein,

When the rescue operation is performed, the control unit alternately switches on and off all switching elements belonging to the other of the upper arm and the lower arm as the on operation.

3. The control device of an elevator according to claim 2, wherein,

When the rescue operation is performed, the control unit alternately switches on and off all the switching elements belonging to the other of the upper arm and the lower arm so that a duty ratio of an on time to an off time of the switching element becomes a ratio corresponding to a weight of the car as the on operation.

4. The control device of an elevator according to claim 3, wherein,

The control unit stores information that associates a duty ratio at which dynamic braking is generated at the motor with a weight inside the car, wherein in the dynamic braking, a braking force smaller than a torque generated at the sheave due to a difference between the weight of the car and the weight of the counterweight is caused to act,

As the on operation, on and off of all the switching elements belonging to the other of the upper arm and the lower arm are alternately switched so as to be a duty ratio corresponding to the measured weight of the inside of the car based on the information of the correspondence relationship.

5. The control device of an elevator according to claim 4, wherein,

The control unit performs a learning operation as follows during an operation of moving the car by using the unbalanced torque: and determining a duty ratio for making the car be at a specified speed, and establishing correspondence between the determined duty ratio and the weight inside the car, thereby creating information of the correspondence.

6. The control device of an elevator according to any one of claims 1 to 5, wherein,

When the rescue operation is performed, the control unit turns off one of the upper arm and the lower arm and turns on the other, and then turns on the one of the upper arm and the lower arm and turns off the other.

7. The control device of an elevator according to any one of claims 1 to 5, wherein,

The elevator control device further comprises a fault detection unit for detecting a fault of any switching element among the plurality of switching elements constituting the upper arm and the lower arm and a fault portion of the switching element,

The control unit performs the rescue operation when the failure detection unit detects a failure of the switching element, and determines an arm corresponding to a failure location detected by the failure detection unit among the upper arm and the lower arm as an arm performing the conduction operation in the rescue operation.

8. The control device of an elevator according to claim 7, wherein,

The fault detection unit detects a case where a switching element has a turn-on fault as a fault location,

The control unit causes an arm including a switching element in which a conduction failure has occurred, out of the upper arm and the lower arm, to perform a conduction operation in the rescue operation when the failure detection unit detects a conduction failure.

9. The control device of an elevator according to claim 7 or 8, wherein,

The fault detection unit detects a case where a switching element has an off fault as a fault location,

When the failure detection unit detects an off failure, the control unit causes an arm, which does not include a switching element in which the off failure has occurred, of the upper arm and the lower arm to perform an on operation in the rescue operation.

10. The control device of an elevator according to any one of claims 1 to 9, wherein,

When the control unit receives a signal of a door zone plate corresponding to a stop position of the car during the rescue operation, the control unit controls a brake for braking the sheave so that the car stops at the stop position.