Controller of motor

Abstract

To adjust a current control gain of a motor by performing simple calculation, with a simple configuration.SOLUTION: A controller of a motor according to the present disclosure comprises a current command part for generating a stepwise current command value, a current control part for controlling a current value flowing to the motor so as to follow the current command value, and a gain calculation part. The gain calculation part calculates a control gain at the current control part according to a comparison result obtained by comparing an actual current value flowing to the motor when an elapsed time from generation of the current command value becomes a reference time with a reference current value associated with the reference time, or by comparing another elapsed time till the current flowing to the motor becomes the reference current value from the generation of the current command value with the reference time associated with the reference current value.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a control device for an electric motor. [Background technology]

[0002] Patent Document 1 describes a control device for controlling a motor. The control device described in Patent Document 1 acquires data on voltage and current for current control and performs machine learning to optimize the control gain. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-34844 Summary of the Invention [Problem to be solved by the invention]

[0004] Machine learning such as that described in Patent Document 1 generally requires complex calculations, making it difficult to implement on inexpensive calculation devices such as general-purpose microcomputers. To solve this problem, the present disclosure provides an improved control device that can appropriately adjust the current control gain of an electric motor with a simpler configuration and calculations. [Means for solving the problem]

[0005] As an example, the control device for an electric motor in the present disclosure includes a current command unit that generates a step-like current command value, a current control unit that controls the value of the current flowing through the electric motor so as to follow the current command value, and a gain calculation unit that compares the actual value of the current flowing through the electric motor when the elapsed time since the current command value was generated becomes a reference time with a reference current value associated with the reference time, and calculates a control gain of the current control unit according to the comparison result.

[0006] As another example, the motor control device in the present disclosure includes a current command unit that generates a step-like current command value, a current control unit that controls the value of the current flowing through the motor so as to follow the current command value, and a gain calculation unit that compares the elapsed time from when the current command value is generated until the current flowing through the motor reaches a reference current value with a reference time associated with the reference current value, and calculates a control gain of the current control unit according to the comparison result. [Effects of the Invention]

[0007] According to the control device of the present disclosure, it is possible to adjust the current control gain of the motor with a simple configuration and simple calculation. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a block diagram showing the overall configuration of a system including an electric motor and a control device according to a first embodiment of the present disclosure. [Figure 2] FIG. 3 is a diagram illustrating an example of a time change in step response of the control device according to the first embodiment of the present disclosure. [Figure 3] 4 is a flowchart showing a control operation of gain adjustment executed by the control device according to the first embodiment of the present disclosure. [Figure 4] 4 is a flowchart showing a control operation of gain adjustment executed by the control device according to the first embodiment of the present disclosure. [Figure 5] 10A and 10B are diagrams illustrating an example of a time response of a current and a time series transition of adjustment magnifications of a P gain and an I gain when control of gain adjustment according to the first embodiment of the present disclosure is applied. [Figure 6] 4 is a flowchart showing a control operation of gain adjustment executed by the control device according to the first embodiment of the present disclosure. [Figure 7] FIG. 10 is a diagram illustrating an example of a time change in step response of a control device according to a second embodiment of the present disclosure. [Figure 8] 10 is a flowchart showing a control operation of gain adjustment executed by a control device according to a second embodiment of the present disclosure. [Figure 9]10 is a flowchart showing a control operation of gain adjustment executed by a control device according to a second embodiment of the present disclosure. [Figure 10] FIG. 11 is a block diagram showing the configuration of a system including an elevator door device and a control device according to a third embodiment of the present disclosure. [Figure 11] 11 is a flowchart showing a control operation of gain adjustment executed by a control device according to a third embodiment of the present disclosure. [Figure 12] FIG. 10 is a block diagram showing the overall configuration of a system including an elevator and a control device according to a fourth embodiment of the present disclosure. [Figure 13] 10 is a flowchart showing a control operation of gain adjustment executed by a control device according to a fourth embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In each drawing, the same or corresponding parts are designated by the same reference numerals, and the description thereof will be simplified or omitted.

[0010] Embodiment 1 Fig. 1 is a block diagram showing the overall configuration of a system including an electric motor and a control device according to a first embodiment of the present disclosure. The electric motor 1 shown in Fig. 1 is a permanent magnet synchronous motor that is rotationally driven by a three-phase alternating current. The rotational position θ, rotational speed, rotational torque, etc. of the electric motor 1 are controlled by the power supplied to the electric motor 1.

[0011] The electric motor 1 is equipped with a rotation sensor 2. The rotation sensor 2 detects the rotation position θ of the electric motor 1. For example, an encoder or a resolver is used as the rotation sensor 2. Other types of rotation sensors may also be used as the rotation sensor 2. Information about the rotation position θ detected by the rotation sensor 2 is used for controlling the rotation position and rotation speed, as a control standard for current, and the like.

[0012] The electric motor 1 is provided with a brake 3 that brakes the electric motor 1. The brake 3 may have any configuration, for example, a disc brake or a drum brake. The brake 3 is controlled by a higher-level control panel (not shown) that controls the rotation of the electric motor 1.

[0013] A control device is connected to the electric motor 1. The control device includes a current command unit 4, a current control unit 5, a voltage coordinate converter 6, a current coordinate converter 7, a power converter 8, a current comparison unit 9, a gain adjustment unit 10, and a current sensor 13.

[0014] The current command unit 4 calculates and outputs a d-axis current command value Id* and a q-axis current command value Iq* of the motor 1. The d-axis current of the motor 1 is a current value that does not contribute, or contributes little, to the rotational torque. Typically, in a permanent magnet synchronous motor, the current command unit 4 sets the current command value Id* to 0 when controlling the rotation of the motor 1. When operating the motor 1 in a specific operating range with high speed and high torque, the current command value Id* may be set to a value other than 0 to perform flux-weakening control to alleviate voltage saturation. The q-axis current of the motor 1 is a current value that contributes to the rotational torque, and the current command unit 4 generates the current command value Iq* when controlling the torque of the motor 1. The current command value Iq* may also be used as an output for position control or speed control of the motor 1, and the current command unit 4 may include a position control system or a speed control system.

[0015] Here, we will explain the operation of the current command unit 4 when adjusting the gain of the current control unit 5. In normal control, the current command values ​​Id* and Iq* are generated to control the rotation of the electric motor 1, but when adjusting the gain of the current control unit 5, a step-like current command value is generated. Note that the step-like current command value may be added to a constant offset current.

[0016] Furthermore, during gain adjustment, the current command unit 4 generates step-like current command values ​​successively. Specifically, after generating step-like current command values, the current command value is set to 0 after a predetermined time has elapsed. Then, after the current command value is set to 0 and a predetermined time has elapsed, a step-like current command value is generated again. This becomes a command value like a pulse wave. The current command unit 4 repeats these operations a predetermined number of times. Note that the predetermined time and the predetermined number of times are set in advance.

[0017] The current command unit 4 generates a step-like current command value when the electric motor 1 is stopped. That is, the gain adjustment of the current control unit 5 is executed when the electric motor 1 is stopped. The stopped state of the electric motor 1 may be a state in which the electric motor 1 is braked by the brake 3, or a state in which the electric motor 1 is stopped by a mechanical load.

[0018] The current control unit 5 includes a P gain 51, an I gain 52, and an integrator 53. The current control unit 5 controls the current flowing through the electric motor 1 by PI control. The current control unit 5 generates a d-axis voltage command value Vd* or a q-axis voltage command value Vq* so that the actual current value flowing through the electric motor 1 follows the d-axis current command value Id* or the q-axis current command value Iq* from the current command unit 4.

[0019] Generally, the PI gain is set using the parameters of the motor 1. Specifically, the P gain 51 is set as P gain = ωc × L using the inductance L of the motor 1, and the I gain 52 is set as I gain = ωc × R using the resistance value R of the motor 1. Here, ωc is the current control band. If the motor 1 is an interior permanent magnet motor, the inductance differs between the d-axis and the q-axis. In this case, the P gain is set as P gain = ωc × Ld for the d-axis, and as P gain = ωc × Lq for the q-axis. Here, Ld is the inductance of the d-axis, and Lq is the inductance of the q-axis.

[0020] When the inductance set in the P gain 51 and the resistance set in the I gain 52 are equal to the actual inductance and resistance of the electric motor 1, the closed-loop characteristics from the current command value Id*, which is the output of the current command unit 4, to the actual current value Id, or from the current command value Iq* to the actual current value Iq, become a first-order lag system, which will hereinafter be referred to as an ideal response. Conversely, when the closed-loop characteristics from the current command values ​​Id*, Iq* to the actual current values ​​Id, Iq are not a first-order lag system, this indicates that the inductance set in the P gain 51 and the resistance set in the I gain 52 differ from the actual inductance and resistance of the electric motor 1.

[0021] The voltage coordinate converter 6 receives as input the value of the rotational position θ of the electric motor 1 detected by the rotation sensor 2 and the d-axis or q-axis voltage command values ​​Vd*, Vq* generated by the current control unit 5. Based on the rotational position θ, the voltage coordinate converter 6 converts the coordinate system of the voltage command values ​​Vd* and Vq* into a UVW coordinate system. That is, based on the input rotational position θ and voltage command values ​​Vd* and Vq*, the voltage coordinate converter 6 calculates and outputs the corresponding U-phase voltage command value Vu*, V-phase voltage command value Vv*, and W-phase voltage command value Vw*.

[0022] The power converter 8 is an amplifier that supplies power for controlling the electric motor 1. As an example, the power converter 8 has the function of a PWM inverter. The power converter 8 is supplied with a bus voltage from a power supply system. The power converter 8 generates a corresponding PWM signal by performing carrier comparison of the voltage command values ​​Vu*, Vv*, and Vw* that are the output of the voltage coordinate converter 6. The power converter 8 uses the generated PWM signal as a switching command for the switching elements of the inverter. The power converter 8 converts the power from the power supply system based on the switching command and supplies the power to the electric motor 1.

[0023] The current sensor 13 detects the value of the current flowing through each phase of the electric motor 1. That is, the current sensor 13 detects the value of the current flowing through the U phase, the value of the current flowing through the V phase, and the value of the current flowing through the W phase of the electric motor 1. Hereinafter, the value of the current flowing through the U phase, the value of the current flowing through the V phase, and the value of the current flowing through the W phase detected by the current sensor 13 will also be referred to as the actual current value Iu, the actual current value Iv, and the actual current value Iw, respectively.

[0024] The current coordinate converter 7 receives the rotational position θ of the electric motor 1 detected by the rotation sensor 2 and the three-phase actual current values ​​Iu, Iv, and Iw of the electric motor 1 detected by the current sensor 13. Based on the rotational position θ, the current coordinate converter 7 converts the coordinate system of the actual current values ​​Iu, Iv, and Iw into a dq coordinate system. That is, based on the input rotational position θ and actual current values ​​Iu, Iv, and Iw, the current coordinate converter 7 calculates and outputs the corresponding d-axis actual current value Id and q-axis actual current value Iq. The output actual current values ​​Id and Iq are used by the current control unit 5 and the current comparison unit 9.

[0025] The current comparator 9 and gain adjuster 10 function as a gain calculator that adjusts the control gain of the current controller 5. The current comparator 9 receives the d-axis actual current value Id or the q-axis actual current value Iq, which are the output of the current coordinate converter 7. The current comparator 9 compares the change in the input actual current value Id or Iq with the ideal response to a step-like current command value, i.e., the change in the current value associated with a first-order lag system. The current comparator 9 generates a gain adjustment command according to the comparison result and outputs it to the gain adjuster 10.

[0026] The principle of the gain calculation unit will be explained in more detail below. Note that when "Idq" or "Idq*" is displayed, it indicates either the d-axis or q-axis current value. As described above, when the inductance set in the P gain 51 of the current control unit 5 and the resistance set in the I gain 52 are equal to the actual inductance and resistance of the motor 1, the characteristics from the current command value Id* or Iq*, which is the output of the current command unit 4, to the actual current value Id or Iq become a first-order lag system.

[0027] If the set value of the control band of the current control unit 5 is ωc, when the current command unit 4 generates and outputs a step-like current command value, i.e., when a step command is given, the ideal response from the current command value Id* to the actual current value Id, and from the current command value Iq* to the actual current value Iq can be expressed by equation (1).

[0028]

number

[0029] In equation (1), t is the time elapsed since the start of the step command. From equation (1), if the time elapsed since the step command, t, is specified, the magnitude of the current at elapsed time t can be determined. For example, when ωc = 100 and t = 0.02, the calculation can be made as follows: Idq = 0.864 × Idq*.

[0030] The current comparison unit 9 compares the ideal response current value at each reference time from the start of the step command calculated using equation (1) with the actual current value, and outputs a gain adjustment command based on the comparison result.

[0031] Here, the time constant T is a time that indicates the characteristics of the step response, and there is a relationship of time constant T=1 / ωc. Rewriting equation (1) using the time constant T gives equation (2).

[0032]

number

[0033] When the elapsed time t from the start of the step command becomes t=T, (2) is Idq=0.632×Idq*, and it is known that the current value of the ideal response to the step command reaches approximately 63% of the current command value Idq*. Furthermore, for example, when a time five times the time constant T has passed, that is, when t=5T, Idq=0.993×Idq*, and the current value of the ideal response reaches 99% of the current command value Idq*.

[0034] In this way, by comparing the time constant that characterizes the step response and the actual current value Idq over a time longer than the time constant with the current value of the ideal response, the P gain 51 and I gain 52 of the current control unit 5 can be adjusted.

[0035] Specifically, the time constant is a quantity related to the rise of the current, which can be changed by adjusting the P gain 51. On the other hand, a time longer than the time constant, for example, five times the time constant, is a quantity related to the convergence of the current, which can be changed by adjusting the I gain 52. Note that these are just examples, and it is possible to adjust the P gain 51 and the I gain 52 by comparing the actual current value Idq at any time with the current value of the ideal response.

[0036] The gain adjustment unit 10 adjusts the P gain 51 and the I gain 52 of the current control unit 5 based on a gain adjustment command from the current comparison unit 9. Specifically, when the current comparison unit 9 issues an adjustment command for the P gain 51, the gain adjustment unit 10 changes the P gain by a predetermined factor. Furthermore, when the current comparison unit 9 issues an adjustment command for the I gain 52, the gain adjustment unit 10 changes the I gain by the predetermined factor. Hereinafter, the predetermined factor is represented as (1±α). α is an arbitrary value greater than 0. For example, α is set to 0.1, in which case the gain is adjusted to 1.1 or 0.9. Furthermore, for example, α is set to 0.2, in which case the gain is adjusted to 1.2 or 0.8. For example, when a 20% change in gain is desired, α is set to 0.2, and when a 50% change is desired, α is set to 0.5. The values ​​of α for the P gain and the I gain may be the same. Furthermore, the multiplication factors may be different between the P gain and the I gain, for example, by setting α for the P gain to 0.5 and setting the multiplication factor for the P gain to 0.5 or 1.5, and by setting α for the I gain to 0.3 and setting the multiplication factor for the I gain to 1.3 or 0.7. Furthermore, α when increasing the gain and α when decreasing the gain may be set to different values, and the multiplication factor when increasing and the multiplication factor when decreasing may be set to different values.

[0037] In addition, while the current control unit 5 is shown in a single block diagram in Figure 1, this indicates that the current is controlled by the same mechanism for the d-axis and q-axis, and that the P gain 51 and I gain 52 are adjusted. Gain adjustment can be performed separately for the d-axis and q-axis, or simultaneously for the d-axis and q-axis. When adjusting the q-axis, the electric motor 1 may generate torque and rotate, so it must be stopped by the brake 3 to prevent rotation. When the electric motor 1 rotates, a back electromotive force is generated, which causes a disturbance to the current control and worsens the accuracy of the gain adjustment.

[0038] FIG. 2 is a diagram showing an example of a change over time in the step response in this embodiment. In FIG. 2, the horizontal axis represents time t, and the vertical axis represents the current value Idq. Furthermore, solid line a represents the current command value Idq*, dashed line b represents the current value of the ideal response, and solid line c represents the actual current value Idq. In current control of the electric motor 1, for a step-like current command value Idq*, as shown by dashed line b, the ideal response is a first-order lag system as shown in equations (1) and (2). In contrast, FIG. 2 shows a case where the actual current value Idq does not match the ideal response.

[0039] In FIG. 2, IT1 is the actual current value (solid line c) when the elapsed time t from the start of the step command is the reference time T1. The current range determined by the ideal response current value (dashed line b) at the reference time T1 is set to be equal to or greater than the lower limit IT1min and equal to or less than the upper limit IT1max. The upper limit IT1max and lower limit IT1min that define the current range are values ​​obtained by adding a margin to the ideal response current value (dashed line b) at the reference time T1. There are no limitations on the method for calculating the current range. For example, the current range may be calculated by multiplying the ideal response current value at the reference time T1 by a fixed factor (1±β), or by adding or subtracting a fixed value.

[0040] The upper limit value IT2max and lower limit value IT2min indicating the current range at reference time T2 in Figure 2, and the upper limit value IT3max and lower limit value IT3min indicating the current range at reference time T3 are also set in the same way by adding a margin to the current value of the ideal response (dashed line b) at each of reference times T2 and T3.

[0041] In the example shown in FIG. 2, when the elapsed time t from the start of the step command reaches the reference time T1, the actual current value IT1 (solid line c) falls outside the current range (IT1min or more, IT1max or less) determined by the ideal response. Specifically, the actual current value IT1 is smaller than the lower limit IT1min. Here, the reference time T1 is set to a time related to the rise of the current after the start of the step. At this time, in order to bring the actual current value IT1 within the current range (IT1min or more, IT1max or less) determined by the ideal response, the P gain is multiplied, for example, by 1.1. Note that the P gain is changed when the next step command is generated.

[0042] Next, when the elapsed time t reaches the reference time T2, the actual current value IT2 falls within the current range (IT2min or more, IT2max or less) determined by the ideal response current value (dashed line b). The reference time T2 is set to a time related to the rise of the current, but during this elapsed time, no gain adjustment command is output and the P gain is not adjusted.

[0043] Next, when the elapsed time t reaches the reference time T3, the actual current value IT3 is outside the current range (IT3min or more, IT3max or less) determined by the current value of the ideal response (dashed line b). Specifically, the actual current value IT3 is smaller than the lower limit IT3min. The reference time T3 is set to a time related to the convergence of the current after the start of the step. At this time, the I gain is multiplied by, for example, 1.1 to bring the actual current value IT3 within the current range (IT3min or more, IT3max or less). Note that the I gain is changed when the next step command is generated.

[0044] 2, the current comparator 9 determines that the P gain needs to be increased by 1.1 at reference time T1 and the I gain needs to be increased by 1.1 at reference time T3. As a result, the current comparator 9 outputs a gain adjustment command to the gain adjuster 10 to increase the P gain by 1.1 and the I gain by 1.1.

[0045] Although FIG. 2 illustrates three reference times, T1, T2, and T3, the reference time may be one or more, and there is no limit to the number of reference times that can be set. The more reference times there are and the more timings at which the actual current and the ideal response are compared, the more precisely the actual current value can be matched to the ideal response value. However, the reference time for adjusting the P gain may be set within the time associated with the rise of the current after the start of the step response, and the reference time for adjusting the I gain may be set to the time associated with the convergence of the current after the start of the step response. Alternatively, the reference time for adjusting the P gain may be set to a value close to or less than the time constant, and the reference time for adjusting the I gain may be set to a time longer than the time constant.

[0046] Fig. 3 is a flowchart showing an example of the control operation of the gain adjustment executed by the control device. The example in Fig. 3 shows the control operation during P gain adjustment executed near the reference time T1 in Fig. 2. The control process in Fig. 3 is repeatedly executed at a predetermined timing when it is detected that the electric motor 1 is stopped, for example.

[0047] 3, a step-like current command value is generated in step S301. Next, in step S302, it is determined whether the elapsed time t from the start of the step command has reached a reference time T1. If it is determined in step S302 that the elapsed time t has not reached the reference time T1, the process returns to step S302, and the determination process of step S302 is repeated at predetermined control intervals until the elapsed time t reaches T1.

[0048] If it is determined in step S302 that the elapsed time t has reached the reference time T1, then in step S303, the actual current value IT1 at the reference time T1 is obtained, and it is determined whether the actual current value IT1 is greater than or equal to the lower limit value IT1min and less than or equal to IT1max.

[0049] If it is determined that the actual current value IT1 is equal to or greater than the lower limit IT1min and equal to or less than IT1max, the process proceeds to step S304, where the P gain is not adjusted, i.e., no gain adjustment command is output, and the current process is terminated.

[0050] If it is determined in step S303 that the actual current value IT1 is not equal to or greater than the lower limit IT1min or equal to or less than IT1max, the process proceeds to step S305, where it is determined whether the actual current value IT1 is smaller than the lower limit IT1min.

[0051] If it is determined in step S305 that the actual current value IT1 is smaller than the lower limit IT1min, the process proceeds to step S306, where the P gain is set to (1+α). Once the P gain adjustment magnification is determined in step S306, the current process is terminated.

[0052] On the other hand, if it is determined in step S305 that the actual current value IT1 is not smaller than the lower limit IT1min, it can be said that the actual current value IT1 is greater than the upper limit IT1max. In this case, the process proceeds to step S307, where the P gain is set to (1-α). Once the P gain adjustment magnification is determined in step S307, the current process is terminated.

[0053] In FIG. 3, whether or not to adjust the P gain is determined only at the reference time T1. However, for example, a similar control operation may be performed at the reference time T2 as well, by acquiring the actual current value IT2, and adjusting the P gain to (1+α)(1-α) when it is smaller than IT2min or larger than IT2max.

[0054] Fig. 4 is a flowchart showing an example of a control operation for gain adjustment executed by the control device. Fig. 4 shows a control example when I gain adjustment is executed near the reference time T3 in Fig. 2. The control operation in Fig. 4 is executed repeatedly, for example, at a predetermined timing when it is detected that the electric motor 1 is in a stopped state. The control operation in Fig. 4 may be configured to be executed immediately after the control operation in Fig. 3.

[0055] 4, a step-like current command value is generated in step S401. Next, in step S402, it is determined whether the elapsed time t from the start of the step command has reached a reference time T3. If it is determined in step S402 that the elapsed time t has not reached the reference time T3, the process returns to step S402, and the determination process of step S402 is repeated at predetermined control intervals until the elapsed time t reaches the reference time T3.

[0056] On the other hand, if it is determined in step S402 that the elapsed time t is equal to the reference time T3, then in step S403, the actual current value IT3 at the reference time T3 is obtained, and it is determined whether the actual current value IT3 is greater than or equal to the lower limit value IT3min and less than or equal to the upper limit value IT3max.

[0057] If it is determined in step S402 that the actual current value IT3 is equal to or greater than the lower limit IT3min and equal to or less than the upper limit IT3max, the process proceeds to step S404, where the I gain is not adjusted, i.e., no gain adjustment command is output, and the current process is terminated.

[0058] On the other hand, if it is determined in step S403 that the actual current value IT3 is not greater than the lower limit value IT3min and not less than the upper limit value IT3max, it is determined in step S405 whether the actual current value IT3 is smaller than the lower limit value IT3min.

[0059] If it is determined in step S405 that the actual current value IT3 is smaller than the lower limit IT3min, the process proceeds to step S406, where the I gain is multiplied by (1+α). After the adjustment magnification of the I gain is determined in step S406, the current process is terminated.

[0060] On the other hand, if it is not determined in step S405 that the actual current value IT3 is smaller than the lower limit IT3min, it can be said that the actual current value IT3 is greater than the upper limit IT3max. In this case, the process proceeds to step S407, where the I gain is multiplied by (1-α). After the adjustment magnification of the I gain is determined in step S407, the current process is terminated.

[0061] 5 is a diagram illustrating an example of a time response of a current, a time series transition of an adjustment magnification of a P gain, and a time series transition of an adjustment magnification of an I gain when the gain adjustment control of this embodiment is applied. As shown in FIG. 5, the P gain 51 or the I gain 52 is adjusted by repeating a step response.

[0062] In the example shown in Fig. 5, the first step response is performed with the P gain adjustment magnification = 1 and the I gain adjustment magnification = 1, i.e., with the gains remaining at the initial setting values. At this time, the P gain adjustment magnification and the I gain adjustment magnification are determined according to the control operations shown in Figs. 3 and 4.

[0063] In the second time, the P gain 51 and the I gain 52 are adjusted using the P gain adjustment magnification and the I gain adjustment magnification determined in the first time, and a step response is executed. In this case, the P gain adjustment magnification and the I gain adjustment magnification are also determined in accordance with the control operation shown in FIGS.

[0064] In the third run, the P gain 51 and I gain 52 are adjusted using the P gain adjustment magnification and I gain adjustment magnification determined in the second run, and a step response is executed. By repeating this process thereafter, the P gain and I gain converge to appropriate gains, that is, gains that make the closed loop characteristics of current control an ideal response = first-order lag system.

[0065] By repeatedly performing step responses, the control operations shown in Figures 3 and 4 can be performed at both the rising and falling edges of a step. Specifically, the adjustment magnifications for the P gain and I gain are determined at the rising edge of a step, and the falling edge of the step is controlled using these adjustment magnifications. The adjustment magnifications for the P gain and I gain are then determined again, and the rising edge of the next step is controlled using these magnifications. In this way, the P gain and I gain can be adjusted at both the rising and falling edges of a step. This shortens the time required for adjustment.

[0066] Fig. 6 is a flowchart for explaining the control process of gain adjustment executed by the control device. The control process of Fig. 6 is repeatedly executed at a predetermined timing when it is detected that the electric motor 1 is in a stopped state, for example.

[0067] In the process of Fig. 6, first, in step S601, a step-like current command value is generated. Next, in step S602, current comparison is performed based on the lapse of predetermined reference times T1 and T3 from the generation of the current command, and in step S603, a gain adjustment magnification is determined based on the current comparison result. That is, in steps S601 to S603, the control process of Fig. 3 or 4 is executed.

[0068] Next, in step S604, it is determined whether the step response has been performed a reference number of times. The reference number of times is set in advance. If it is determined in step S604 that the step response has not been performed the reference number of times, then in step S605, P gain and I gain adjustment is performed according to the gain adjustment magnification determined in step S603. Thereafter, the process returns to step S601 again. On the other hand, if it is determined in step S604 that the step response has been performed the reference number of times, the current process is terminated.

[0069] Note that the determination of whether step S604 has ended may be made based on, for example, whether the gain adjustment multiplier determined in step S603 has stopped changing, instead of based on a reference number of times. The fact that the gain adjustment multiplier in step S603 has stopped changing indicates that the P gain 51 and the I gain 52 have converged to appropriate values, and this can be used as a reference. Here, whether the gain adjustment multiplier has stopped changing can be determined based on whether the calculated gain adjustment multiplier has remained the same consecutively, or whether it has remained the same value a predetermined number of times.

[0070] When the P gain 51 and I gain 52 are at appropriate values, that is, when the closed-loop characteristics of the current control loop become ideal response = first-order lag system, the P gain 51 satisfies the relationship P gain = ωc × L using the inductance L of the motor 1, and the I gain 52 satisfies the relationship I gain = ωc × R using the resistance R of the motor 1. Here, ωc is the current control band. Therefore, the value obtained by dividing the P gain by ωc is the inductance of the motor 1, and the value obtained by dividing the I gain by ωc is the resistance of the motor 1. In this way, by adjusting the P gain 51 and the I gain 52, the inductance and resistance of the motor 1 can be estimated. The calculated inductance and resistance can be used for other motor control parameters, or can be used to detect the temperature of the motor 1 from the resistance value, etc.

[0071] As described above, in the control device of this embodiment, when a step command is generated by the current command unit 4, the current comparator 9 compares the actual current value with the current value associated with the ideal closed-loop characteristics of current control of the motor 1, and adjusts the P gain 51 and I gain 52 of the current control unit 5 based on the comparison result. By repeatedly performing this process using multiple step commands, it is possible to obtain appropriate values ​​for the P gain 51 and I gain 52, i.e., gains that make the closed-loop characteristics of current control a first-order lag system. In this way, in this embodiment, the current control gain can be adjusted with a simple configuration in which the ideal current is compared with the actual current and the gain is changed.

[0072] Embodiment 2 The control device of embodiment 2 has the same configuration as the control device of embodiment 1 except that the process for determining whether or not to perform gain adjustment in current comparison unit 9 is different from the process in current comparison unit 9 of embodiment 1. The differences from the control device of embodiment 1 will be described below.

[0073] A current comparator 9 of the control device according to the second embodiment receives the d-axis actual current value Id or the q-axis actual current value Iq, which are the output of the current coordinate converter 7, as input, and outputs a gain adjustment command to a gain adjuster 10. Specific processing in the current comparator 9 will now be described.

[0074] The current comparison unit 9 measures the elapsed time t from the start of the step command until the actual current value becomes the reference current value by comparing it with the reference time when the current value of the ideal response (i.e., first-order delay system) indicates the reference current value, and calculates the gain adjustment command by comparing the reference time calculated to the reference current value with the measured actual elapsed time.

[0075] Here, the ideal response is as shown in the above equation (2), and by modifying this, the following equation (3) can be obtained.

[0076]

number

[0077] In equation (3), the time constant T is determined by the set value ωc of the control band of the current control unit 5, and Idq* is the magnitude of the step command. Therefore, once the actual current value Idq is determined as the reference current value, the time t at which the actual current value Idq = the reference current value is determined.

[0078] For example, from equation (2), when the time t is equal to the time constant T, the current value is Idq = 0.632Idq*, and substituting this into equation (3) gives t = T. That is, when the actual current value Idq becomes 0.632Idq*, if the time t from the start of the step command is equal to the time constant T, then the actual current value is in agreement with the ideal response. Alternatively, a range such as Tmin < t < Tmax may be given, and if the time falls within this range, it may be determined that the response is in agreement with the ideal response.

[0079] Furthermore, for example, when Idq = 0.993Idq*, t = 5T is obtained. That is, when the actual current value Idq becomes 0.993Idq*, if the time t from the start of the step is equal to 5T, then the actual current value is in agreement with the ideal response. Alternatively, a range such as 5Tmin < t < 5Tmax may be given, and if the time falls within this range, it may be determined that the response is in agreement with the ideal response.

[0080] In the step response, the response near the time constant is strongly related to the P gain, and the response after sufficient time has elapsed from the time constant is strongly related to the I gain. Thus, by comparing the time constant that characterizes the step response and the current values at times longer than the time constant, the P gain 51 and the I gain 52 of the current control unit 5 can be adjusted. Specifically, the time constant is a quantity related to the current rise, which can be changed by adjusting the P gain 51. On the other hand, the time five times the time constant is a quantity related to the current convergence, which can be changed by adjusting the I gain 52. Note that these are just examples, and it is possible to adjust the P gain 51 and the I gain 52 by comparing the actual current at any reference current value.

[0081] Based on the gain adjustment command from the current comparison unit 9, the gain adjustment unit 10 adjusts the P gain 51 and the I gain 52 of the current control unit 5. Specifically, when a P gain 51 adjustment command is issued from the current comparison unit 9, the gain adjustment unit 10 changes the P gain by a predetermined magnification (1 ± α). Also, when an I gain 52 adjustment command is issued from the current comparison unit 9, the gain adjustment unit 10 changes the I gain by a predetermined magnification (1 ± α).

[0082] Fig. 7 is a diagram showing an example of the change over time in step response. In Fig. 7, the horizontal axis represents time t, and the vertical axis represents the current value. Also in Fig. 7, the solid line a represents the current command value, the dashed line b represents the ideal response, and the solid line c represents the actual current value. In current control of the electric motor 1, the ideal response (dashed line b) to the step-like current command value (solid line a) is a first-order lag system as shown in equations (1) and (2).

[0083] FIG. 7 shows a case where the actual current value (solid line c), i.e., Id or Iq, does not match the ideal response. Here, the reference current value is IT1, and the time when the current value of the ideal response becomes the reference current value IT1 is the reference time T1. A time range with a margin is set to be equal to or greater than a lower limit value T1min and equal to or less than an upper limit value T1max. Note that the reference time T1 is the elapsed time from the start of the step command. The margin may be the reference time T1 multiplied by a factor, or may be obtained by adding or subtracting a predetermined value.

[0084] The same applies to the reference current values ​​IT2 and IT3 in FIG. 7, the time range (above the lower limit T2min and below the upper limit T2max) and the time range (above the lower limit T3min and below the upper limit T3max) corresponding thereto.

[0085] In Figure 7, when a step command is initiated and the actual current value reaches the reference current value IT1, the actual elapsed time t1 measured from the initiation of the step command is outside the time range determined by the ideal response (greater than T1min and less than T1max). Specifically, the elapsed time t1 is greater than the upper limit value T1max. The reference current value IT1 is a current value calculated from the time related to the rise of the current in the step response. Therefore, it can be seen that the actual current value rises more slowly than the ideal response. In this case, the P gain is multiplied by 1.1 to bring the elapsed time t1 within the time range (greater than T1min and less than T1max). Note that the P gain or I gain will be changed when the next step command is generated.

[0086] Next, when the actual current value reaches the reference current value IT2, the actual elapsed time t2 measured from the start of the step is within the time range determined by the ideal response (longer than T2min and shorter than T2max), so no gain adjustment is performed during this elapsed time t2, and no gain adjustment command is output.

[0087] Next, when the actual current value reaches the reference current value IT3, the actual elapsed time t3 measured from the start of the step is outside the time range determined by the ideal response (greater than or equal to T3min and less than or equal to T3max). Specifically, the elapsed time t3 is smaller than the lower limit value T3min. The reference current value IT3 is a current value related to the convergence of the current after the start of the step. Therefore, it can be said that the actual current value reaches the convergence value faster than the ideal response. In this case, the I gain is multiplied by 0.9 to keep the elapsed time t3 within the time range (greater than or equal to T3min and less than or equal to T3max).

[0088] 7, the current comparator 9 determines that the P gain needs to be increased by 1.1 because the elapsed time t1 at which the reference current value IT1 is reached is greater than the upper limit T1max. The current comparator 9 also determines that the I gain needs to be increased by 0.9 because the elapsed time t3 at which the reference current value IT3 is reached is less than the lower limit T3min. As a result, the current comparator 9 outputs a command to the gain adjuster 10 to increase the P gain by 1.1 and the I gain by 0.9.

[0089] Although FIG. 7 shows three reference current values, IT1, IT2, and IT3, the number of reference current values ​​that can be set is not limited, and one or more reference current values ​​may be set. The more reference current values ​​are set and the more times the actual current and the ideal response are compared, the more precisely the actual current value can match the ideal response value. However, the reference current value for adjusting the P gain may be set to a current value during the rise of the current, and the reference current value for adjusting the I gain may be set to a current value near the convergence value of the current. Alternatively, the reference current value for adjusting the P gain may be set according to a current value of the ideal response corresponding to a time period near or less than the time constant, and the reference current value for adjusting the I gain may be set according to a current value of the ideal response corresponding to a time period sufficiently longer than the time constant. The gain adjustment command is not limited to 1.1 or 0.9. As described above, α in the adjustment magnification factor (1±α) of the gain adjustment command can be set to any value.

[0090] Fig. 8 is a flowchart showing an example of the control operation of gain adjustment executed by the control device. Fig. 8 shows a control example when P gain adjustment is executed near the reference current value IT1 in Fig. 7. Fig. 8 is executed in place of the control process in Fig. 3. In Fig. 8, first, a step-like current command value is generated in step S801.

[0091] Next, in step S802, it is determined whether the actual current value has reached the reference current value IT1. If the actual current value has not reached the reference current value IT1, the process returns to step S802, and the determination in step S802 is repeatedly performed at predetermined control intervals until the actual current value reaches the reference current value IT1.

[0092] If it is determined in step S802 that the actual current value has become the reference current value IT1, then in step S803, the elapsed time t1 at which the actual current value became the reference current value IT1 is obtained, and it is determined whether the elapsed time t1 is within the time range T1min or more and T1max or less.

[0093] If it is determined in step S803 that the elapsed time t1 is within the time range of T1min or more and T1max or less, the process proceeds to step S804, where the P gain is not adjusted and the current processing is terminated.

[0094] On the other hand, if it is determined in step S803 that the elapsed time t1 is not within the time range of T1min to T1max, then in step S805 it is determined whether the elapsed time t1 is smaller than the lower limit T1min.

[0095] If it is determined in step S805 that the elapsed time t1 is less than the lower limit T1min, the process proceeds to step S806, where the P gain is multiplied by (1-α). As described above, α is an arbitrary value. After the P gain adjustment magnification is determined in step S806, the current process ends.

[0096] If it is determined in step S805 that the elapsed time t1 is equal to or greater than the lower limit T1min, it can be said that the elapsed time t1 is greater than the upper limit T1max. In this case, the P gain is multiplied by (1+α). As mentioned above, α is an arbitrary value. After the P gain adjustment magnification is determined in step S807, the current process is terminated.

[0097] Fig. 9 is a flowchart showing an example of the control operation of gain adjustment executed by the control device. Fig. 9 shows a control example when adjusting the I gain executed near the reference current value IT3 in Fig. 7. Fig. 9 is executed in place of the control process in Fig. 4. In Fig. 9, first, in step S901, a step-like current command value is generated.

[0098] Next, in step S902, it is determined whether the actual current value is equal to the reference current value IT3. If it is determined in step S902 that the actual current value is not equal to the reference current value IT3, the determination process of step S902 is repeatedly executed at predetermined control intervals until the actual current value becomes equal to the reference current value IT3.

[0099] On the other hand, if it is determined in step S902 that the actual current value is equal to the reference current value IT3, the elapsed time t3, which is the time when the actual current value becomes the reference current value IT3, is acquired in step S903, and it is then determined whether the elapsed time t3 is within the time range of T3min to T3max.

[0100] If it is determined in step S903 that the elapsed time t3 is within the time range of T3min or more and T3max or less, the process proceeds to step S904, where the I gain is not adjusted, and the current processing is terminated.

[0101] If it is determined in step S903 that the elapsed time t3 is not within the time range of T3min or more and T3max or less, the process proceeds to step S905, where it is determined whether the elapsed time t3 is less than the lower limit T3min.

[0102] If it is determined in step S903 that the elapsed time t3 is less than the lower limit T3min, the process proceeds to step S904, where the I gain is multiplied by (1-α). As described above, α is an arbitrary value. After the I gain adjustment magnification is determined in step S906, the current process is terminated.

[0103] If it is determined in step S905 that the elapsed time t3 is equal to or greater than the lower limit T3min, it can be said that the elapsed time t3 is greater than the upper limit T3max. In this case, the process proceeds to step S907, where the I gain is multiplied by (1+α). As mentioned above, α is an arbitrary value. After the I gain adjustment magnification is determined in step S907, the current process is terminated.

[0104] Although detailed description will be omitted in this embodiment, the adjustment of the P gain and I gain described above is repeatedly executed multiple times, similar to that described in embodiment 1. That is, the adjustment magnifications of the P gain and the I gain are determined according to the control processing in Figures 8 and 9, and the next adjustment control of the P gain and the I gain is executed using the determined adjustment magnifications of the P gain and the I gain. In this way, the P gain and the I gain are converged to appropriate gains, that is, gains that make the closed-loop characteristics of current control an ideal response = first-order lag system.

[0105] As described above, in the control device according to this embodiment, when a step command is generated by the current command unit 4, the current comparator 9 measures the elapsed time until the actual current value of the electric motor 1 becomes a response current associated with ideal closed-loop characteristics of current control of the electric motor 1. The measured elapsed time is then compared with the time corresponding to the current value associated with the ideal closed-loop characteristics, and the P gain 51 and I gain 52 of the current control unit 5 are adjusted based on the comparison result. By repeatedly performing this adjustment using multiple step commands, it is possible to obtain appropriate gains for the P gain 51 and I gain 52, i.e., gains that result in a first-order lag system in the closed-loop characteristics of current control. As such, in this embodiment, it is possible to adjust the current control gain with a simple configuration in which the ideal current is compared with the actual current value and the gain is changed.

[0106] Embodiment 3 In the third embodiment, a case will be described in which the control device of the first or second embodiment is applied to an electric motor of an elevator door device. FIG. 10 is a block diagram showing the overall configuration of a system including an elevator door device and a control device according to the third embodiment. In the third embodiment, a case will be described in which the current control gain of the electric motor of the elevator door device is adjusted. Only the parts different from the first embodiment will be described here.

[0107] In the system shown in Fig. 10, a door 11 is driven to open and close by an electric motor 1. The electric motor 1 is equipped with a rotation sensor 2. The rotation sensor 2 may detect the position of the door 11 based on the rotation position θ of the electric motor 1. Information on the position of the door 11 detected by the rotation sensor 2 is used to determine the acceleration position and deceleration position of the door 11, as well as whether it is fully closed or fully open.

[0108] The current command unit 4 calculates and outputs a d-axis current command value Id* and a q-axis current command value Iq* of the electric motor 1. The d-axis current of the electric motor 1 is a current value that does not contribute or contributes little to the rotational torque. Normally, the current command unit 4 sets the current command value Id* to 0 when performing control to open the door 11, control to close the door 11, control to maintain the door 11 in a fully open state, and control to maintain the door 11 in a fully closed state. Note that when operating the electric motor 1 in a specific operating range of high speed and high torque to open or close the door 11, the current command value Id* may be set to a value other than 0 in order to perform flux-weakening control.

[0109] The q-axis current of the electric motor 1 is a current value that contributes to the rotational torque, and the current command unit 4 generates Iq* when controlling the torque of the electric motor 1. Iq* may also be treated as an output for position control or speed control of the electric motor 1, and the current command unit 4 may include a position control system or a speed control system. Since door position control and speed control are required for the operation of the door 11, the current command unit 4 is considered to include position control and speed control.

[0110] Here, the operation of the current command unit 4 when performing gain adjustment of the current control unit 5 of the electric motor 1 of the elevator door 11 will be described. In normal control, the current command values ​​Id* and Iq* are generated to control the rotation of the electric motor 1 for opening and closing the elevator door 11. However, when performing gain adjustment of the current control unit 5, a step-like current command value is generated. Note that the step-like current command value may be added to a constant offset current. The current command unit 4 also generates step-like current command values ​​continuously. Specifically, the current command unit 4 generates a step-like current command value, and then sets the current command value to 0 after a predetermined time has elapsed. Then, after setting the current command value to 0 and a predetermined time has elapsed, the current command unit 4 generates a step-like current command value again. The current command unit 4 repeats these operations a predetermined number of times.

[0111] The current command unit 4 generates a step-like current command value when the electric motor 1 is stopped. That is, the gain adjustment of the current control unit 5 is performed when the electric motor 1 is stopped. More specifically, for example, when the elevator door 11 is detected to be in a fully open or fully closed state, the current command unit 4 generates a step-like current command value and performs gain adjustment.

[0112] As an example, the fully open or fully closed state of the door 11 is detected based on the rotational position θ detected by the rotation sensor 2. When the door 11 is fully open or fully closed, the rotational position θ detected by the rotation sensor 2 is a constant value, and this value is detected to detect the fully open or fully closed state of the door 11. Alternatively, the fully open or fully closed state of the door 11 may be detected based on a change in the rotational position θ, i.e., the speed. Alternatively, as another method, a configuration may be adopted in which a sensor attached at the fully closed position of the door 11 and a sensor attached at the fully open position are used to detect the fully open or fully closed state of the door 11.

[0113] Here, the current command value output by the current command unit 4 can be set to any magnitude because the d-axis current does not contribute to the torque of the electric motor 1. On the other hand, the q-axis current is related to the torque of the electric motor 1, so care must be taken with its magnitude and direction. When the elevator door 11 is fully open, i.e., when passengers are getting on or off, the electric motor 1 generates torque in the opening direction to prevent the door from closing. In contrast, if a stepped q-axis current command value is applied in the closing direction, the door may close while passengers are getting on or off. Therefore, in the fully open state, a stepped q-axis current command value is generated in the direction that opens the door 11. Conversely, in the fully closed state, i.e., when the elevator is moving or waiting, a stepped q-axis current command must be applied to prevent the door from opening. Opening the door 11 while the elevator is moving may cause an emergency stop for the elevator, and opening the door 11 while waiting may cause discomfort to passengers. Therefore, in the fully closed state, a stepped q-axis current command value is generated in the direction that closes the door.

[0114] 11 is a flowchart showing an example of a control operation of gain adjustment executed by the control device according to Embodiment 3. FIG. 11 shows a control process executed in place of the control process of FIG.

[0115] 11, first, in step S1101, it is determined whether the door 11 is in a fully closed state or a fully open state. If it is determined in step S1101 that the door 11 is not in a fully closed state or a fully open state, the current processing is terminated.

[0116] If it is determined in step S1101 that the door 11 is in the fully closed state or the fully open state, then in step S1102 a step-like current command value is generated. The subsequent processing is the same as in the case of Fig. 6, in step S1103 a current comparison is performed between the actual current value and the reference current value when the elapsed time from the generation of the current command value reaches the reference time, and in step S1104 a gain adjustment magnification is determined based on the current comparison result. This is executed by the control processing of Fig. 3 or 4.

[0117] Next, once the gain adjustment magnification is determined, it is determined in step S1105 whether or not the step response has been performed a reference number of times. If it is determined in step S1105 that the step response has not been performed the reference number of times, gain adjustment is performed in step S1106 using the control processing of FIG. 3 or 4, and the processing returns to generating a current command value in step S1102. If it is determined in step S1105 that the step response has been performed the reference number of times, the current processing ends.

[0118] As described in the first embodiment, the determination of the end of step S1105 may be made based on a reference number of times, or may be configured to determine the end when it is detected that the gain adjustment magnification of step S1104 has stopped changing.

[0119] 11 has been described as a case where gain adjustment is performed by comparing the actual current value with the reference current value when the elapsed time becomes the reference time T1, T2, T3, etc., through the control processing in Figures 3 and 4. However, instead of this, a configuration may be adopted in which gain adjustment is performed based on a comparison of the elapsed time when the actual current becomes the reference current value with the reference time through the control processing in Figures 8 and 9.

[0120] As described above, according to the third embodiment, when the elevator is in service and door 11 is not being opened or closed, a current command value is generated so that door 11 does not move. Therefore, the current control gain can be adjusted without operating motor 1. This makes it possible to adjust the current control gain of motor 1 without causing discomfort to elevator passengers.

[0121] Embodiment 4 Fig. 12 is a block diagram showing the overall configuration of a system including an elevator and a control device according to Embodiment 4. In Embodiment 4, the control device according to Embodiment 1 or 2 is applied to an elevator motor, and adjusts the current control gain of the motor. Only the parts that differ from Embodiment 1 or 2 will be described here.

[0122] The elevator car 12 moves up and down due to the rotation of the electric motor 1, and moves to the destination floor. The electric motor 1 moves the car 12 up and down via a sheave and rope. The electric motor 1 or sheave is equipped with a brake 3 for braking, and the braking by the brake 3 is released while the elevator is running, and when it arrives at the floor, the brake 3 brakes the electric motor 1 or sheave to maintain a stopped state. The electric motor 1, rotation sensor 2, sheave, and brake 3 are sometimes collectively called the hoisting machine.

[0123] The current command unit 4 calculates and outputs the d-axis current command value Id* and the q-axis current command value Iq* of the electric motor 1. The d-axis current of the electric motor 1 is a current value that does not contribute, or contributes very little, to the rotational torque. Normally, the current command unit 4 sets the current command value Id* to 0 while the elevator is running. On the other hand, when the weight of the passengers and the weight of the counterweight allow for a sufficient balance torque, the elevator will run at an increased speed. At this time, the current command value Id* may be set to a value other than 0 in order to perform flux-weakening control.

[0124] The q-axis current of the electric motor 1 is a current value that contributes to the rotational torque, and the current command unit 4 generates Iq* when controlling the torque of the electric motor 1. The q-axis current command value Iq* may also be treated as an output for position control or speed control of the electric motor 1, and the current command unit 4 may include a position control system and a speed control system. Since position control and speed control are necessary when an elevator is traveling, the current command unit 4 is considered to include position control and speed control.

[0125] Here, the operation of the current command unit 4 when performing gain adjustment of the current control unit 5 of the elevator motor 1 will be described. In normal control, the current command values ​​Id* and Iq* are generated to control the rotation of the electric motor 1 for running the elevator. However, when performing gain adjustment of the current control unit 5, the current command unit 4 generates a step-like current command value. Note that the current command value may be obtained by adding a step-like current command value to a constant offset current.

[0126] Furthermore, the current command unit 4 continuously generates step-like current command values. Specifically, after generating a step-like current command value, the current command unit 4 sets the current command value to 0 after a predetermined time has elapsed. Then, after a predetermined time has elapsed since setting the current command value to 0, the current command unit 4 again generates a step-like current command value. The current command unit 4 repeats these operations a predetermined number of times.

[0127] The current command unit 4 generates a step-like current command value when the electric motor 1 is stopped. That is, the gain adjustment of the current control unit 5 is performed when the electric motor 1 is stopped. More specifically, for example, when the elevator has finished traveling and is stopped at a floor designated by a passenger, a step-like current command value is generated and the gain adjustment is performed.

[0128] As an example, the stopped state of the elevator is detected based on the rotational position θ detected by the rotation sensor 2. When the elevator is stopped, the rotational position θ detected by the rotation sensor 2 is a constant value, and this is detected to detect the stopped state. Alternatively, the stopped state may be detected based on a change in the rotational position θ, i.e., the speed. As another method, the stopped state of the elevator may be detected based on the state of the brake 3. Alternatively, for example, the stopped state may be detected using a position sensor installed in the elevator hoistway.

[0129] Fig. 13 is a flowchart showing an example of the control operation of gain adjustment executed by the control device according to embodiment 4. In Fig. 13, first, in step S1301, it is determined whether the elevator is stopped, that is, whether the car is at a floor. If it is determined in step S1301 that the elevator is not stopped, the current control gain is not adjusted, and the current processing is terminated.

[0130] If it is determined in step S1301 that the elevator is stopped, a step-like current command value is generated in step S1302. Next, as in the case of Fig. 6, a current comparison is performed in step S1303 between the actual current value when the elapsed time from generation of the current command value reaches the reference time and the reference current value of the ideal response, and in step S1304, a gain adjustment magnification is determined based on the current comparison result. This is executed by the control processing of Fig. 3 or 4.

[0131] Once the gain adjustment magnification is determined, it is determined in step S1305 whether or not the step response has been performed a reference number of times. If it is determined in step S1305 that the step response has not been performed the reference number of times, gain adjustment according to Figures 3 and 4 is performed in step S1306, and the process returns to generating a current command value in step S1302. If it is determined in step S1305 that the step response has been performed the reference number of times, the current process ends.

[0132] As described in the first embodiment, the determination of the end of step S1305 may be made based on a reference number of times, or may be configured to determine the end when it is detected that the gain adjustment magnification of step S1304 has stopped changing.

[0133] 13 has been described as a case in which gain adjustment is performed by comparing the actual current value when the elapsed time becomes the reference time T1, T2, T3, etc. with the reference current value through the control processes of FIGS. 3 and 4. However, instead of this, a configuration may be adopted in which gain adjustment is performed based on a comparison of the elapsed time when the actual current becomes the reference current value with the reference time through the control processes of FIGS. 8 and 9.

[0134] As described above, according to the control device of the fourth embodiment, a current command value for adjusting the current control gain is generated when the elevator is in service and the car is not traveling. Therefore, the current control gain can be adjusted without operating the motor 1. This makes it possible to adjust the current control gain of the motor 1 without causing discomfort to elevator passengers.

[0135] The above describes in detail preferred embodiments, but the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the claims.

[0136] Various aspects of the present disclosure are summarized below as appendices. (Appendix 1) a current command unit that generates a step-like current command value; a current control unit that controls a value of a current flowing through the electric motor so as to follow the current command value; a gain calculation unit that compares an actual current value flowing through the electric motor when a reference time has elapsed since the generation of the current command value with a reference current value associated with the reference time, and calculates a control gain of the current control unit in accordance with a comparison result; A control device for an electric motor comprising: (Appendix 2) a current command unit that generates a step-like current command value; a current control unit that controls a value of a current flowing through the electric motor so as to follow the current command value; a gain calculation unit that compares an elapsed time from when the current command value is generated until the current flowing through the electric motor reaches a reference current value with a reference time associated with the reference current value, and calculates a control gain of the current control unit according to the comparison result; A control device for an electric motor comprising: (Appendix 3) The reference current value is set based on ideal closed-loop characteristics when the parameters of the motor set in the current control unit match the actual parameters of the motor. 3. A control device for an electric motor according to claim 1 or 2. (Appendix 4) The reference time is set based on ideal closed-loop characteristics when the parameters of the motor set in the current control unit match the actual parameters of the motor. 3. A control device for an electric motor according to claim 1 or 2. (Appendix 5) the current command unit generates the step-like current command value a plurality of times, the gain calculation unit calculates the control gain a plurality of times based on a current value flowing through the electric motor for each of the plurality of current command values; 5. A control device for an electric motor according to any one of appendices 1 to 4. (Appendix 6) the current control unit is a PI controller, the gain calculation unit calculates a P gain and an I gain of the current control unit from a step response to the step-like current command value. 6. A control device for an electric motor according to any one of appendices 1 to 5. (Appendix 7) The gain calculation unit When the reference time is shorter than the time constant of an ideal closed loop characteristic when the parameters of the motor set in the current control unit and the actual parameters of the motor match, the P gain is calculated; If the reference time is longer than the time constant, the I gain is calculated. 7. A control device for an electric motor according to claim 6. (Appendix 8) The gain calculation unit changes the P gain or the I gain by a preset magnification. 8. A control device for an electric motor according to claim 6 or 7. (Appendix 9) Estimating the inductance of the motor using the P gain; Estimating a resistance value of the electric motor using the I gain; 9. A control device for an electric motor according to any one of appendices 6 to 8. (Appendix 10) the current command unit generates the step-like current command value when the electric motor is in a braking state, The gain calculation unit calculates the gain when the electric motor is in a braking state. 10. A control device for an electric motor according to any one of appendices 1 to 9. (Appendix 11) The electric motor is an electric motor that opens and closes elevator doors. 11. A control device for an electric motor according to claim 10. (Appendix 12) The electric motor is an electric motor for an elevator hoisting machine. 11. A control device for an electric motor according to claim 10. [Explanation of symbols]

[0137] REFERENCE SIGNS LIST 1 electric motor, 2 rotation sensor, 3 brake, 4 current command section, 5 current control section, 6 voltage coordinate converter, 7 current coordinate converter, 8 power converter, 9 current comparison section, 10 gain adjustment section, 11 door, 13 current sensor, 51 P gain, 52 I gain, 53 integrator

Claims

1. a current command unit that generates a step-like current command value; a current control unit that controls a value of a current flowing through the electric motor so as to follow the current command value; a gain calculation unit that compares an actual current value flowing through the electric motor when a time elapsed since the generation of the current command value is a reference time with a reference current value associated with the reference time, and calculates a control gain of the current control unit in accordance with a comparison result; A control device for an electric motor comprising:

2. a current command unit that generates a step-like current command value; a current control unit that controls a value of a current flowing through the electric motor so as to follow the current command value; a gain calculation unit that compares an elapsed time from when the current command value is generated until the current flowing through the electric motor reaches a reference current value with a reference time associated with the reference current value, and calculates a control gain of the current control unit according to the comparison result; A control device for an electric motor comprising:

3. the reference current value is set based on ideal closed-loop characteristics when the parameters of the electric motor set in the current control unit match with the actual parameters of the electric motor. The motor control device according to claim 1 or 2.

4. the reference time is set based on ideal closed-loop characteristics when the parameters of the motor set in the current control unit and the actual parameters of the motor match. The motor control device according to claim 1 or 2.

5. the current command unit generates the step-like current command value a plurality of times, the gain calculation unit calculates the control gain a plurality of times based on a current value flowing through the electric motor for each of the plurality of current command values; The motor control device according to claim 1 or 2.

6. the current control unit is a PI controller, the gain calculation unit calculates a P gain and an I gain of the current control unit from a step response to the step-like current command value. The motor control device according to claim 1 or 2.

7. The gain calculation unit When the reference time is shorter than a time constant in an ideal closed loop characteristic when the parameters of the motor set in the current control unit and the actual parameters of the motor match, the P gain is calculated; If the reference time is longer than the time constant, the I gain is calculated. The motor control device according to claim 6.

8. The gain calculation unit changes the P gain or the I gain by a preset magnification. The motor control device according to claim 6.

9. Estimating the inductance of the motor using the P gain; Estimating a resistance value of the electric motor using the I gain; The motor control device according to claim 6.

10. the current command unit generates the step-like current command value when the electric motor is in a braking state, the gain calculation unit calculates the control gain when the electric motor is in a braking state. The motor control device according to claim 1 or 2.

11. The electric motor is an electric motor that opens and closes elevator doors. The motor control device according to claim 10.

12. The electric motor is an electric motor for an elevator hoisting machine. The motor control device according to claim 10.

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