Elevator control device

Abstract

To provide a technique capable of identifying a characteristic parameter of a hoist by using information about current supplied to the hoist of an elevator and optimizing a control parameter used for controlling the hoist.SOLUTION: This elevator control device comprises: a car; a main rope connected at one end to the car and at the other end to a balance weight; a hoist that winds the main rope on a sheave to lift the car; a hoist control unit that controls the hoist by using a control parameter; and a parameter identification unit that identifies a characteristic parameter of the hoist. The parameter identification unit is configured to identify the characteristic parameter by using a current value flowing through the hoist and unbalance torque generated due to a weight difference between the car and the balance weight. The hoist control unit is configured to set the control parameter on the basis of the characteristic parameter.SELECTED DRAWING: Figure 3

Description

[Technical field]

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

[0002] Patent Document 1 discloses a method for identifying motor parameters in a motor control device using an estimation technique based on a disturbance observer. In this method, the motor parameters are identified based on a disturbance estimate from the disturbance observer, a q-axis current, the disturbance estimate, and a torque detected by a torque detector. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2022-178401 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the technology described in Patent Document 1 cannot identify the characteristic parameters of an electric motor in a system that does not have a torque detector. In addition, the technology described in Patent Document 1 requires estimation calculations such as a disturbance observer, which increases the burden on software.

[0005] The present disclosure has been made to solve the problems described above, and aims to provide a technology for identifying characteristic parameters of an elevator hoist using information on the current supplied to the hoist, and optimizing control parameters used to control the hoist. [Means for solving the problem]

[0006] The elevator control device disclosed herein is an elevator control device that includes a car, a main rope having one end connected to the car and the other end connected to a counterweight, and a hoist that raises and lowers the car by winding the main rope around a sheave, and includes a hoist control unit that controls the hoist using control parameters, and a parameter identification unit that identifies characteristic parameters of the hoist, wherein the parameter identification unit is configured to identify the characteristic parameters using the current value flowing through the hoist and the unbalance torque generated by the weight difference between the car and the counterweight, and the hoist control unit is configured to set the control parameters based on the characteristic parameters. Effect of the Invention

[0007] According to the technology disclosed herein, it is possible to identify characteristic parameters of an elevator hoist using information on the current supplied to the hoist, and to optimize control parameters used to control the hoist. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a configuration diagram of an elevator according to a first embodiment. [Diagram 2] FIG. 4 is a diagram showing an example of changes over time in the q-axis current value and the rotational speed of the hoisting machine when stationary maintenance control is executed in the elevator of the first embodiment. [Diagram 3] 5 is a flowchart showing a routine for identifying a torque constant by the elevator control device of the first embodiment. [Figure 4] FIG. 2 is a diagram illustrating an example of hardware resources of a control device. [Diagram 5] FIG. 11 is a diagram illustrating another example of hardware resources of a control device. [Figure 6] FIG. 11 is a diagram showing an example of a time change in the q-axis current value of the hoisting machine for each car load when stationary maintenance control is executed in the elevator of the second embodiment. [Figure 7] 10 is a flowchart showing a routine for identifying a torque constant by the elevator control device of the second embodiment. [Figure 8]FIG. 11 is a diagram showing an example of the change over time in the q-axis current value of the hoisting machine and the position of the car in the elevator shaft when an upward operation from the bottom floor to the top floor and a downward operation from the top floor to the bottom floor are performed consecutively in an elevator of embodiment 3. [Figure 9] 13 is a flowchart showing a routine for identifying a torque constant by the elevator control device of the embodiment 3. [Figure 10] FIG. 13 is a diagram showing an example of changes over time in the q-axis current value and the rotational speed of the hoisting machine when stationary maintenance control is executed in the elevator of the fourth embodiment. [Figure 11] 13 is a flowchart showing a routine for adjusting current control parameters by the elevator control device of embodiment 4. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment will be described with reference to the drawings. In addition, elements common to the various drawings are given the same reference numerals, and duplicated explanations will be omitted.

[0010] Embodiment 1 1-1. Configuration of the elevator in the first embodiment FIG. 1 is a configuration diagram of an elevator according to a first embodiment. An elevator 100 according to the first embodiment is installed in a facility consisting of a building or the like having multiple floors. An elevator shaft for the elevator 100 is provided in the facility. The elevator shaft is a long space in the vertical direction that spans multiple floors.

[0011] The elevator 100 mainly comprises a hoisting machine 1, a rotation sensor 2, a car 3, a counterweight 4, a main rope 5, a brake device 6, a weighing device 7, a current sensor 8, a power converter 9, and a control device 10.

[0012] The hoisting machine 1 is installed at the top of the hoistway. The hoisting machine 1 includes a sheave and an electric motor that rotates the sheave. A main rope 5 is wound around the sheave of the hoisting machine 1. A car 3 is connected to one end of the main rope. A counterweight 4 is connected to the other end of the main rope 5. The car 3 and counterweight 4 are suspended in the hoistway by the main rope 5 in a bucket-like manner. The car 3 and counterweight 4 move up and down in the hoistway by rotating the sheave of the hoisting machine 1.

[0013] The weight of the counterweight 4 is adjusted based on the weight ratio to the rated capacity CP of the car 3, called the "counter ratio γ." For example, when the counter ratio γ is set to 50%, the weight of the counterweight 4 is adjusted to a value obtained by adding the mass of the car 3 to the weight of 50% of the rated capacity CP.

[0014] The rotation sensor 2 detects the rotation position and rotation speed of the hoist 1 by generating a pulse value according to the rotation of the sheave. For example, an encoder or resolver that generates a signal according to the rotation of the sheave is used as the rotation sensor 2. The detected rotation position and rotation speed are input to the control device 10 and used for position control and speed control of the hoist 1.

[0015] The brake device 6 brakes the rotation of the hoisting machine 1 based on a brake command from the control device 10. The weighing device 7 measures the car load acting on the car 3. The car load measured by the weighing device 7 is input to the control device 10. The current sensor 8 detects the value of a current flowing through the hoisting machine 1. The current value detected by the current sensor 8 is input to the control device 10.

[0016] The power converter 9 applies a voltage to the hoisting machine 1 based on a voltage command calculated by the control device 10. The power converter 9 is, for example, a PWM inverter.

[0017] The control device 10 includes a hoisting machine control unit 12 and a parameter identification unit 14 as functions realized by the processor executing a program. The hoisting machine control unit 12 is a functional block for calculating a voltage command for controlling the hoisting machine 1. Typically, the hoisting machine control unit 12 configures a position control system and a speed control system based on the rotational position and rotational speed of the hoisting machine 1 detected by the rotation sensor 2. The hoisting machine control unit 12 also configures a current control system based on a current value detected by the current sensor 8. The control gains of the position control system, the speed control system, and the current control system of the hoisting machine control unit 12 are adjusted based on the characteristic parameters of the hoisting machine 1 identified in the parameter identification unit 14.

[0018] The parameter identification unit 14 is a functional block for identifying the characteristic parameters of the hoisting machine 1. Typically, the parameter identification unit 14 identifies the characteristic parameters using a current command value as a control command value received from the hoisting machine control unit 12 and a current value detected by the current sensor 8. This process is hereinafter referred to as an "identification process." An example of the characteristic parameter is a torque constant Kt. The torque constant Kt is the torque generated per unit current generated in the hoisting machine 1. The characteristic parameters identified in the identification process are sent to the hoisting machine control unit 12. The hoisting machine control unit 12 adjusts the control parameters of the position control system, the speed control system, and the current control system based on the characteristic parameters.

[0019] 1-2. Overview of identification process Next, an overview of the identification process performed by the parameter identification unit 14 in the first embodiment will be described. When the weights of the car 3 and the counterweight 4 are balanced, the load torque acting on the hoist 1, i.e., the unbalance torque T1 generated due to the weight difference between the car 3 and the counterweight 4, becomes zero. On the other hand, when the weights of the car 3 and the counterweight 4 are not balanced, the unbalance torque T1 acts on the hoist 1 due to the weight difference between the car 3 and the counterweight 4. In the identification process, the parameter identification unit 14 uses the unbalance torque T1 to calculate a torque constant Kt as a characteristic parameter.

[0020] When no load is applied to the cage 3, the mass of the cage 3 is M1, the mass of the counterweight 4 is M2, the acceleration of gravity is g, and the diameter of the sheave of the hoisting machine 1 is r, then the unbalanced torque T1 can be expressed by the following equation (1).

[0021] T1 = (M1 - M2) × g × r (1)

[0022] The mass M2 of the counterweight 4 can be rewritten as the following equation (2) using the mass M1 of the car 3, the rated capacity CP of the car 3, and the counter rate γ.

[0023] M2 = M1 + γ × CP (2)

[0024] From equations (1) and (2), the unbalanced torque T1 can be expressed by the following equation (3): As shown in equation (3), if the counter rate γ, the rated capacity CP, and the sheave diameter r of the hoisting machine 1 are known, the unbalanced torque T1 can be calculated as a known value.

[0025] T1 = -γ × CP × g × r (3)

[0026] The torque T2 generated by the hoisting machine 1 can be expressed by the following equation (4) using the q-axis current Iq and torque constant Kt of the hoisting machine 1.

[0027] T2 = Kt × Iq ​​(4)

[0028] Here, when the braking by the brake device 6 is released and the stationary holding control for feedback controlling the torque T2 of the hoist 1 so that the speed of the hoist 1 becomes 0 (zero) is performed by the hoist control unit 12, the unbalanced torque T1 and the torque T2 are balanced. Therefore, while the car 3 is stationary due to the stationary holding control, the torque constant Kt can be expressed as the following equation (5). Kt = T1 / Iq (5)

[0029] FIG. 2 is a diagram showing an example of time changes of the q-axis current value and the rotation speed of the hoisting machine 1 when the stationary holding control is executed in the elevator of the first embodiment. In the example shown in this figure, when the brake device 6 is released from a state in which the brake device 6 brakes the hoisting machine 1 so that the rotation speed of the hoisting machine 1 becomes 0, the hoisting machine 1 rotates due to the unbalanced torque T1. The hoisting machine control unit 12 executes stationary holding control to generate a q-axis current Iq for generating a torque T2 in the hoisting machine 1 so as to make the rotation speed 0. Then, when the rotation speed becomes 0, the q-axis current Iq becomes a constant value, and the q-axis current Iq at this time becomes a stationary holding current at which the torque T2 and the unbalanced torque T1 are balanced. The parameter identification unit 14 identifies the torque constant Kt by substituting the unbalanced torque T1 and the stationary holding current detected by the current sensor 8 into the formula (5). The identified torque constant Kt is sent to the hoisting machine control unit 12.

[0030] The hoist control unit 12 uses the identified torque constant Kt to set the control gain of the hoist control unit 12, particularly the speed control gain. This makes it possible to keep the control performance constant even in a situation where the characteristics of the hoist 1 have changed due to temperature change or aging.

[0031] When the torque constant Kt is unknown, the torque constant Kt is provisionally calculated using the rated torque, rated output, rated rotation speed, and rated current written on the motor nameplate of the hoisting machine 1. The hoisting machine control unit 12 performs stationary maintenance control using the calculated torque constant Kt. Then, the parameter identification unit 14 calculates an accurate torque constant Kt based on the actual q-axis current Iq of the hoisting machine 1 during stationary maintenance control and the torque T2 acting on the hoisting machine 1.

[0032] Moreover, before releasing the brake device 6, a current that generates a torque equivalent to the unbalanced torque T1 may be applied to the hoisting machine 1 in advance. According to such control, when stationary maintenance control is performed, the time until the rotation speed converges to 0 can be shortened.

[0033] 1-3. Specific processing executed by the control device in the first embodiment 3 is a flowchart showing a routine for identifying a torque constant by the elevator control device of the embodiment 1. In the embodiment 1, the control device 10 executes this routine when the car load is 0, that is, when there is no passenger in the car 3. In this case, the unbalance torque T1 can be calculated as a known quantity based on the formula (3).

[0034] In step S100, the brake device 6 that brakes the hoisting machine 1 is released. When the brake is released, in step S102, stationary maintenance control is performed to generate a torque T2 in the hoisting machine 1 so that the speed of the hoisting machine 1 becomes zero.

[0035] Next, in step S104, it is determined whether the rotation speed detected by the rotation sensor 2 is equal to or less than a reference value. The reference value here is, for example, 0. Alternatively, the reference value may be a value close to 0. As a result, if the determination is not established, the process returns to step S102, and the stationary maintenance control process is executed again. On the other hand, if the determination is established, the process proceeds to step S106.

[0036] In step S106, a stationary current value is acquired. Here, the acquired current value may be subjected to a filter process, or a value obtained by acquiring data multiple times in a sampling period of the control device 10 and averaging the data may be acquired as the stationary current value. When the process of step S106 is completed, the process proceeds to step S108.

[0037] In step S108, the torque constant Kt is identified by substituting the stationary holding current value acquired in step S106 and the unbalance torque T1, which is a known amount, into equation (5) to calculate the torque constant Kt.

[0038] As is clear from the above description, according to the elevator 100 of the first embodiment, the torque constant Kt can be identified as a characteristic parameter of the electric motor of the hoisting machine 1, using the stationary holding current detected during execution of stationary holding control. This makes it possible to optimize the control parameters of the hoisting machine control unit 12, thereby making it possible to maintain constant control performance.

[0039] 1-4.Modifications The elevator 100 of the first embodiment may adopt the following modified aspects.

[0040] 1-4-1. Hardware resources of the control device 10

[0041] 4 is a diagram showing an example of hardware resources of the control device 10. The control device 10 includes, as hardware resources, a processing circuit 106 including a processor 102 and a memory 104. The processing circuit 106 may include multiple processors 102. The processing circuit 106 may include multiple memories 104.

[0042] In this embodiment, the hoist control unit 12 and the parameter identification unit 14 indicate functions possessed by the control device 10. The functions of the hoist control unit 12 and the parameter identification unit 14 can be realized by software written as a program, firmware, or a combination of software and firmware. The program is stored in the memory 104. Alternatively, the program may be recorded in a computer-readable recording medium. The control device 10 realizes the functions of the hoist control unit 12 and the parameter identification unit 14 by executing the program stored in the memory 104 by the processor 102 (computer).

[0043] The processor 102 is also called a CPU (Central Processing Unit), central processing unit, processing unit, arithmetic unit, microprocessor, microcomputer, or DSP. The memory 104 may be a semiconductor memory, a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, or a DVD. Possible semiconductor memories include RAM, ROM, flash memory, EPROM, and EEPROM.

[0044] FIG. 5 is a diagram showing another example of the hardware resources of the control device 10. In the example shown in FIG. 5, the control device 10 includes a processor 102, a memory 104, and a processing circuit 106 including dedicated hardware 108. FIG. 5 shows an example in which a part of the functions of the control device 10 is realized by the dedicated hardware 108. All of the functions of the control device 10 may be realized by the dedicated hardware 108. As the dedicated hardware 108, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC, an FPGA, or a combination of these can be adopted. Note that the above-mentioned modified examples of the hardware resources of the control device 10 can also be applied to the control device 10 of other embodiments described later.

[0045] Embodiment 2 2-1. Features of the elevator in the second embodiment In the elevator of the above-mentioned embodiment 1, the torque constant is identified when the car load is 0. In contrast, the elevator of the embodiment 2 is characterized by a control for identifying the torque constant under any car load condition. An outline of the identification process performed in the parameter identification unit 14 in the embodiment 1 will be described below.

[0046] If the mass of the car 3 when no load is acting on the car 3 is M1, the car load acting on the car 3 is M0, the mass of the counterweight 4 is M2, the acceleration of gravity is g, and the radius of the sheave of the hoisting machine 1 is the sheave diameter r, the unbalanced torque T1 can be expressed by the following equation.

[0047] T1 = (M1 + M0 - M2) × g × r (6)

[0048] From equation (6) and equation (2), the unbalance torque T1 can be expressed by the following equation (7).

[0049] T1=(M0−γ×CP)×g×r (7)

[0050] As shown in equation (7), if the counter rate γ, rated capacity CP, and sheave diameter r of the hoisting machine 1 are known, the unbalance torque T1 can be calculated as a known value by measuring the cage load M0 of the cage 3 using the weighing device 7.

[0051] 6 is a diagram showing an example of a time change in the q-axis current value of the hoisting machine 1 for each car load when stationary maintenance control is executed in the elevator of the embodiment 2. In this diagram, car loads of 0%, 30%, and 80% indicate the ratio of the car load to the rated capacity CP of the car 3.

[0052] In the example shown in this figure, when the brake device 6 is released from a state in which the brake device 6 brakes the hoisting machine 1 so that the rotation speed of the hoisting machine 1 becomes 0, the hoisting machine 1 rotates due to the unbalanced torque T1 when the weights of the car 3 and the counterweight 4 are not balanced. The hoisting machine control unit 12 executes stationary maintenance control to generate a q-axis current Iq for generating a torque T2 in the hoisting machine 1 so as to make the rotation speed 0. Then, when the rotation speed becomes 0, the q-axis current Iq becomes a constant value, and the q-axis current Iq at this time becomes a stationary maintenance current at which the torque T2 and the unbalanced torque T1 are balanced. As shown in FIG. 6, the stationary maintenance current has a different value depending on the magnitude of the car load. Therefore, if the stationary maintenance current is detected using the current sensor 8, the torque constant Kt can be identified using the formula (5).

[0053] The parameter identification unit 14 calculates the unbalance torque T1 by substituting the car load M0 measured by the weighing device 7 into the formula (7). Then, the parameter identification unit 14 identifies the torque constant Kt by substituting the calculated unbalance torque T1 and the stationary holding current detected by the current sensor 8 into the formula (5). The identified torque constant Kt is sent to the hoisting machine control unit 12.

[0054] The hoist control unit 12 uses the identified torque constant Kt to set the control gain of the hoist control unit 12, particularly the speed control gain. This makes it possible to keep the control performance constant even in a situation where the characteristics of the hoist 1 have changed due to temperature change or aging.

[0055] 2-2. Specific processing executed by the control device in the second embodiment Fig. 7 is a flowchart showing a routine for identifying a torque constant by the elevator control device of embodiment 2. The routine shown in Fig. 7 is executed when the rotational speed of the hoisting machine 1 is held at 0 by the brake device 6 in a state in which a car load is acting.

[0056] In steps S200 to S206, the control device 10 executes the same processes as those in steps S100 to S106. When the process in step S206 is completed, the process proceeds to step S208.

[0057] In step S208, the unbalance torque T1 is calculated. Here, the control device 10 calculates the unbalance torque T1 by substituting the car load M0 measured by the weighing device 7, the known counter rate γ, the rated capacity CP, and the sheave diameter r of the hoisting machine 1 into equation (7). When the processing of step S208 is completed, the processing proceeds to step S210.

[0058] In step S210, the torque constant Kt is identified by substituting the stationary holding current value acquired in step S206 and the unbalance torque T1 calculated in step S208 into equation (5).

[0059] As is clear from the above description, according to the elevator 100 of the second embodiment, even in a state where the car load M0 is acting, the torque constant Kt as a characteristic parameter of the motor of the hoisting machine 1 can be identified by using the stationary holding current detected during execution of the stationary holding control. This makes it possible to optimize the control parameters of the hoisting machine control unit 12, thereby making it possible to maintain constant control performance.

[0060] Embodiment 3 3-1. Features of the elevator control device in the third embodiment The elevator control device of the third embodiment is characterized by control for identifying the torque constant Kt while the elevator is traveling.

[0061] While the elevator is running, the torque components generated by the hoist 1 include a torque that compensates for the unbalanced torque T1 in equation (7), a torque generated in accordance with the acceleration and deceleration, a torque that compensates for running losses in the elevator shaft, and a torque generated due to the difference in weight between the car 3 side and the counterweight 4 side of the main rope 5 connecting the car 3 and counterweight 4.

[0062] Here, when the elevator runs at a constant speed, the torque generated according to the acceleration / deceleration can be considered to be 0. Also, when the car 3 is located at the middle of the elevator's ascent / descent stroke, the weight of the main rope 5 on the car 3 side and the weight of the counterweight 4 side become equal, so the torque generated due to the weight difference of the main rope 5 can be considered to be 0. In other words, when the elevator runs at a constant speed at the middle of the ascent / descent stroke, the torque TUP during the ascent operation of the hoist 1 and the torque TDN during the descent operation can be considered to be the sum of the torque compensating for the unbalanced torque T1 and the torque compensating for the running loss, respectively. Also, the running loss during the ascent operation can be considered to have the same magnitude as the running loss during the descent operation but with a different sign. Therefore, the torque TUP during the ascent operation of the hoist 1 and the torque TDN during the descent operation are expressed by the following equations (8) and (9).

[0063] TUP=Kt×I1=Kt×(I0+IL1) ···(8) TDN=Kt×I2=Kt×(I0-IL2)=Kt×(I0-IL1) ···(9)

[0064] In equations (8) and (9), the first current value I1 is the q-axis current value when traveling at a central position in the ascending stroke at a constant speed during ascending operation, and the second current value I2 is the q-axis current value when traveling at a central position in the ascending stroke at a constant speed during descending operation. In addition, IL1 is a current value for compensating for traveling loss during ascending operation, and IL2 is a current value for compensating for traveling loss during descending operation. And, I0 is a current value for compensating for unbalanced torque T1. From equations (8) and (9), the relationship between the current value I0, the first current value I1, and the second current value I2 is as shown in the following equation (10).

[0065] (I1+I2) / 2=I0 (10)

[0066] As shown in equation (10), the first current value I1 when traveling at a central position in the ascending stroke at a constant speed during ascending operation and the second current value I2 when traveling at a central position in the ascending stroke at a constant speed during descending operation are detected by the current sensor 8, and the current value I0 that compensates for the unbalanced torque can be obtained by averaging these values. Therefore, the torque constant Kt can be calculated by the following equation (11).

[0067] Kt=T1 / I0=T1 / ((I1+I2) / 2) ···(11)

[0068] 3-2. Specific example of identification process in embodiment 3 Fig. 8 is a diagram showing an example of the time change of the q-axis current value of the hoisting machine 1 and the car position in the hoistway when an elevator of the third embodiment performs an upward operation from the lowest floor to the highest floor and a downward operation from the highest floor to the lowest floor in succession. In Fig. 8, the car position is based on the lowest floor. The reference position in the figure indicates the middle position of the upward / downward stroke, that is, the middle position between the lowest floor and the top floor in the hoistway.

[0069] In the example shown in FIG. 8, in the ascending operation of the elevator 100, after the elevator starts traveling at time t1, it starts accelerating in the ascending direction. The acceleration ends at time t2 when the elevator reaches the rated speed, and the elevator travels at a constant speed with a constant torque. Then, at time t4, deceleration begins to stop the elevator at the top floor. In this way, in the ascending operation of the elevator 100, the torque during the constant speed travel is constant, and the torque generated according to the acceleration / deceleration during this period can be considered to be zero. In addition, at time t3 when the elevator passes through the reference position, the torque generated due to the weight difference between the car 3 side and the counterweight 4 side of the main rope 5 can be considered to be zero. From the above, in the ascending operation of the elevator 100, the first current value I1 of the hoisting machine 1 at time t3 when the elevator passes through the intermediate position of the ascending / descending stroke at a constant speed is the sum of the current value I0 for compensating for the unbalanced torque T1 and the current value IL1 for canceling the traveling loss, that is, I1=I0+IL1.

[0070] On the other hand, the descending operation of the elevator 100 is similar to the ascending operation, and when the elevator starts traveling at time t5, it is accelerated in the descending direction until it reaches the rated speed. When the elevator reaches the rated speed at time t6, the acceleration is terminated and the elevator travels at a constant speed with a constant torque. Then, at time t8, deceleration is started to stop the elevator at the lowest floor. In this way, during the descending operation of the elevator 100, the torque during the constant speed travel is constant, and the torque generated according to the acceleration / deceleration during this period can be considered to be zero. Also, at time t7 when the elevator passes through the reference position, the torque generated by the weight difference between the car 3 side and the counterweight 4 side of the main rope 5 can be considered to be zero. From the above, during the descending operation of the elevator 100, the second current value I2 of the hoisting machine 1 at time t7 when the elevator passes through the intermediate position of the ascending / descending stroke at a constant speed is the current value I0 that compensates for the unbalanced torque T1 minus the current value IL2 that cancels out the traveling loss, that is, I2=I0-IL2.

[0071] The first current value I1 and the second current value I2 can be detected by the current sensor 8 while the elevator 100 is traveling. Therefore, by substituting the detected first current value I1 and second current value I2 and the unbalance torque T1 into equation (11), it is possible to identify the torque constant Kt.

[0072] 3-3. Specific Processing Executed by the Control Device in the Third Embodiment 9 is a flowchart showing a routine for identifying a torque constant by the elevator control device according to embodiment 3. The control device 10 executes this routine when the car load M0 is acting.

[0073] In step S300, elevator 100 is operated to ascend from the bottom floor to the top floor. In step S302, a first current value I1 is acquired when passing through a reference position at a constant speed. The reference position here is a position where the weight of main rope 5 located on the car 3 side and the weight of main rope 5 located on the counterweight 4 side are balanced. After that, elevator 100 is stopped at the top floor.

[0074] In step S304, a descending operation is performed from the top floor to the bottom floor. In step S306, a second current value I2 when passing through the reference position at a constant speed is acquired.

[0075] In step S308, the torque constant Kt is identified. Here, the unbalance torque T1 is calculated. The control device 10 calculates the unbalance torque T1 by substituting the car load M0 measured by the weighing device 7, the known counter rate γ, the rated capacity CP, and the sheave diameter r of the hoisting machine 1 into equation (7). Then, the torque constant Kt is calculated by substituting the calculated unbalance torque T1 and the first current value I1 and the second current value I2 acquired in steps S302 and S306 into equation (11).

[0076] As is clear from the above explanation, according to the elevator control device of the third embodiment, even while the elevator 100 is traveling, the torque constant Kt as a characteristic parameter of the electric motor of the hoisting machine 1 can be identified using the current value when passing through a reference position at a constant speed. This makes it possible to optimize the control parameters of the hoisting machine control unit 12, thereby making it possible to maintain constant control performance.

[0077] 3-4.Modifications The elevator control device 10 of the third embodiment may employ the following modified aspects.

[0078] In the identification process, the elevator 100 may first perform a descending operation to obtain the second current value I2, and then perform an ascending operation to obtain the first current value I1. In this case, in the flowchart shown in FIG. 9, the processes of steps S304 and S306 may be performed before the process of step S300.

[0079] The upward operation of elevator 100 in step S300 does not necessarily have to be from the bottom floor to the top floor. In other words, the upward operation here only needs to be able to pass through the reference position at a constant speed. Similarly, the downward operation of elevator 100 in step S304 does not necessarily have to be from the top floor to the bottom floor. In other words, the downward operation here only needs to be able to pass through the reference position at a constant speed.

[0080] The control device 10 may execute the routine shown in Fig. 9 when the car load M0 is not acting. In this case, in step S308, the unbalance torque may be calculated using equation (3).

[0081] Embodiment 4 4-1. Features of the elevator control device in the fourth embodiment The elevator control device of the fourth embodiment is characterized by a process of identifying a current control band as a characteristic parameter of the hoisting machine 1 and adjusting a current control parameter using the identified current control band. The current control parameter here is, for example, a current control gain.

[0082] The car load M0 acting on the car 3 can be measured using the weighing device 7. Therefore, by substituting the car load M0 into the formula (6) to calculate the unbalanced torque T1 and the torque constant Kt into the formula (4), a compensation current value for compensating for the unbalanced torque T1 can be calculated. If the calculated compensation current value is applied in advance before the brake device 6 is released, stationary hold control can be performed to quickly bring the rotation speed close to 0 immediately after the brake device 6 is released. The identification process for identifying the current control band is performed by utilizing a current response when a command for a compensation current value for compensating for the unbalanced torque T1 is applied in a stepped manner before the elevator 100 starts traveling and when the hoisting machine 1 is braked by the brake device 6. The identification process for identifying the current control band will be described in detail below.

[0083] When the hoist 1 is stopped, the relational expression between the current I and voltage V of the motor of the hoist 1 can be expressed by the following equation (12). Here, the current I is the dq-axis current of the motor, and the voltage V is the dq-axis voltage of the motor. Furthermore, L is the inductance of the motor, R is the resistance of the motor, and s is the Laplace operator.

[0084] I = 1 / (Ls + R) × V (12)

[0085] In contrast, the current control of the hoisting machine control unit 12 is generally designed as shown in the following formula (13). Here, ω is the current control band, I* is the current command value, and the proportional gain is expressed as ω×L and the integral gain is expressed as ω×R.

[0086] V=ω / s×(Ls+R)×(I*−I) ···(13)

[0087] By applying equation (13) to equation (12) to derive the closed-loop response, the current I can be expressed as the following first-order lag system.

[0088] I=ω / (s+ω)×I*=1 / (Ts+1)×I* (14)

[0089] Here, T is a time constant, T = 1 / ω. When the current command value I* is given stepwise, the time response is expressed by the following equation.

[0090] I=(1-EXP(-t / T))×I* (15)

[0091] When the time t after the application of the current command value I* becomes t=T, the current I becomes 63% of the current command value I*. In other words, by measuring the time when the actual current I becomes 63% of the current command value I* and detecting the deviation from the ideal time constant T or the deviation between the inverse of the measured time and the current control band ω, the error in the current control gain can be detected. This makes it possible to adjust the gain of the current control. In particular, since the time constant is proportional to the proportional gain, i.e., the inductance, the error in the inductance can be detected. Furthermore, according to equation (15), the ideal value of the current I can be known even at times other than t=T, so the current control gain can be adjusted by comparing the current value at any time with the ideal response.

[0092] 4-2. Specific example of current control parameter adjustment process in embodiment 4 FIG. 10 is a diagram showing an example of the time change of the q-axis current value and the rotation speed of the hoisting machine 1 when the stationary holding control is executed in the elevator of the fourth embodiment. In the example shown in this figure, a compensation current command for compensating for the unbalanced torque T1 is given in a stepwise manner before the brake device 6 is released. As a result, the actual current follows the command value according to the formula (15). At this time, the deviation of the gain of the current control can be detected by measuring the elapsed time Tx at which the actual current reaches 63% of the command value. For example, when the elapsed time Tx is Tx>T, it can be determined that the rise of the actual current is slow and therefore the proportional gain is insufficient. This indicates that the current control band is insufficient compared to the design, and the inductance used to design the proportional gain is smaller than the actual one. Therefore, in such a case, the inductance used to design the proportional gain can be increased to bring the actual current closer to the ideal response.

[0093] On the one hand, when the elapsed time Tx satisfies Tx < T, it can be determined that the proportional gain is excessive because the rise of the actual current is fast. This indicates that the current control bandwidth is excessive compared to the design, and the inductance used to design the proportional gain is larger than the actual value. Therefore, in such a case, the actual current can be made closer to the ideal response by reducing the inductance used in the design of the proportional gain.

[0094] 4-3. Specific Processing Executed in the Control Device in Embodiment 4 FIG. 11 is a flowchart showing a routine in which the elevator control device according to Embodiment 4 adjusts current control parameters. The routine shown in FIG. 11 is executed when the rotation speed of the hoist 1 is held at 0 by the brake device 6 and the car 3 stops.

[0095] In step S400, the hoist control unit 12 commands a compensation current value for compensating the unbalanced torque T1 in steps while the hoist 1 is being braked by the brake device 6. In step S402, the parameter identification unit 14 measures the elapsed time Tx from the command of the compensation current by the hoist control unit 12.

[0096] In the next step S404, the parameter identification unit 14 determines whether the actual current supplied to the hoist 1 has reached a specified ratio with respect to the compensation current value. Here, it is determined whether the actual current detected by the current sensor 8 has reached 63% as the specified ratio of the command value. As a result, if the determination is not affirmed, the process returns to step S402 again, and the measurement of the elapsed time Tx continues.

[0097] On the other hand, if the determination is found to be successful, the process proceeds to step S406. In step S406, the parameter identification unit 14 stops measuring the elapsed time Tx. After the process of step S406 is executed, the process proceeds to step S408. In step S408, the parameter identification unit 14 identifies the measured elapsed time Tx as a time constant T, and identifies the inverse of the time constant T as a current control band ω. Then, the identified time constant T or current control band ω is used to set the control gain of the hoisting machine control unit 12. The control gain here is a current control gain, particularly a proportional gain. In addition, since the proportional gain is proportional to the inductance of the motor, this also means that the inductance is identified.

[0098] As is clear from the above explanation, according to the elevator control device of the fourth embodiment, in stationary holding control, the current control band can be identified from the response of the actual current when a compensation current value that compensates for the unbalanced torque is applied before the release of the brake device 6. This makes it possible to adjust the current control gain using the identified current control band, so that the control performance can be kept constant. Furthermore, since the current control band is proportional to the inductance of the motor, it is also possible to identify the inductance. Moreover, since the time constant is the reciprocal of the current control band, it is also possible to identify the time constant.

[0099] 4-4.Modifications The elevator control device of embodiment 4 may adopt the following modified forms.

[0100] In step S404 of the routine shown in FIG. 11, the specified ratio is not limited to 63%, but may be any ratio. [Explanation of symbols]

[0101] 1 hoisting machine, 2 rotation sensor, 3 cage, 4 counterweight, 5 main rope, 6 brake device, 7 weighing device, 8 current sensor, 9 power converter, 10 control device, 12 hoisting machine control unit, 14 parameter identification unit, 100 elevator, 102 processor, 104 memory, 106 processing circuit, 108 dedicated hardware

Claims

1. A control device for an elevator including a car, a main rope having one end connected to the car and the other end connected to a counterweight, and a hoist that winds the main rope around a sheave to raise and lower the car, A hoist control unit that controls the hoist using a control parameter; A parameter identification unit that identifies characteristic parameters of the hoisting machine, The parameter identification unit The characteristic parameter is identified by using a current value flowing through the hoist and an unbalance torque generated by a weight difference between the cage and the counterweight, The hoist control unit is configured to set the control parameters based on the characteristic parameters. Elevator control device.

2. The hoist control unit is The car is configured to perform stationary maintenance control to release a brake device of the hoisting machine to keep the car stationary when the car load of the car is zero, The parameter identification unit Calculating the unbalance torque using a current value of the hoist during the stationary holding control, a rated capacity of the cage, a counter rate of the counterweight, and a sheave diameter of the hoist; The unbalanced torque is used to identify a torque constant of the hoist as the characteristic parameter. The elevator control device according to claim 1 , which is configured as follows.

3. A weighing device is provided for detecting the load of the cage, The hoist control unit is The vehicle is configured to perform stationary control for releasing a brake device of the hoist to keep the car stationary, The parameter identification unit Calculating the unbalance torque using a current value of the hoist, a rated capacity of the cage, a counter rate of the counterweight, a sheave diameter of the hoist, and a cage load during the stationary holding control; The unbalanced torque is used to identify a torque constant of the hoist as the characteristic parameter. The elevator control device according to claim 1 , which is configured as follows.

4. The hoist control unit is configured to perform an up operation and a down operation of the elevator, The parameter identification unit obtain a first current value of the hoist when the car passes through a reference position of a hoistway at a uniform speed during the ascending operation of the elevator, and a second current value of the hoist when the car passes through the reference position at a uniform speed during the descending operation of the elevator; A torque constant of the hoisting machine is identified as the characteristic parameter by using the first current value, the second current value, and the unbalance torque. The elevator control device according to claim 1 , which is configured as follows.

5. The elevator control device according to claim 4, wherein the reference position is a middle position of the elevator's ascending / descending stroke.

6. The hoist control unit is Before releasing the brake device of the hoisting machine, a command value for supplying a compensation current value to the hoisting machine that compensates for the unbalanced torque is given in a stepwise manner; The parameter identification unit Measure the elapsed time until the current value of the hoisting machine reaches a specified ratio of the compensation current value, A current control band of the hoist control unit is identified as the characteristic parameter based on the elapsed time. The elevator control device according to claim 1 , which is configured as follows.

7. The parameter identification unit identifies an inductance of the hoisting machine as the characteristic parameter based on the current control band. The elevator control device according to claim 6, which is configured as follows.

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