control device

Abstract

A control device (20) comprises a door state detection unit (24), a voltage command unit (27), a voltage estimation unit (33), a resistance estimation unit (30), and a temperature estimation unit (31). The voltage estimation unit (33) estimates a bus voltage value Vdc^ when the door state detection unit (24) detects that a door (13) is in an operating state. The resistance estimation unit (30) estimates the electric resistance value R^ when the door state detection unit (24) detects that the door (13) is in a fully open or a fully closed state. The temperature estimation unit (31) estimates the temperature of a coil T included in a motor (21) by correcting the electric resistance value R^ using the bus voltage value Vdc^.

Description

Technical Field

[0001] The present disclosure relates to a control device for controlling an elevator door.

Background Art

[0002] Patent Document 1 describes a control device for controlling an elevator door. In the control device described in Patent Document 1, the resistance value of the motor is estimated based on the value of the current flowing through the motor that drives the door and the value of the voltage applied to the motor. Further, based on the estimated resistance value, the temperature of the coil of the motor is estimated.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, there is an error between the command value of the voltage applied to the motor and the value of the voltage actually applied. For this reason, there is a problem that the resistance value of the motor cannot be accurately estimated due to this error, and the temperature of the coil of the motor cannot be accurately estimated.

[0005] The present disclosure has been made to solve the above problems. An object of the present disclosure is to provide a control device capable of accurately estimating the temperature of a coil included in a motor that drives an elevator door.

Means for Solving the Problems

[0006] The control device according to this disclosure includes: a door state detection unit for detecting the state of an elevator door; a voltage command unit for generating a voltage command value so that the value of the current flowing to the motor that drives the door follows a current command value; a voltage estimation unit for estimating a bus voltage value supplied to an inverter for driving the motor when the door state detection unit detects that the door is in an operating state; a resistance estimation unit for estimating the electrical resistance value of the motor when the door state detection unit detects that the door is in a fully open or fully closed state; and a temperature estimation unit for estimating the temperature of a coil included in the motor by correcting the electrical resistance value estimated by the resistance estimation unit using the bus voltage value estimated by the voltage estimation unit. [Effects of the Invention]

[0007] According to this disclosure, the temperature of the coils included in the motor that drives the elevator doors can be estimated with high accuracy. [Brief explanation of the drawing]

[0008] [Figure 1] This figure shows an example of an elevator system equipped with a control device according to Embodiment 1. [Figure 2] This figure shows an example of a control device. [Figure 3] This flowchart shows an example of the control device's operation. [Figure 4] This flowchart shows a suitable example of voltage estimation processing. [Figure 5] This is a diagram illustrating the function of the voltage estimation unit. [Figure 6] This flowchart shows a suitable example of resistance estimation processing. [Figure 7] This figure shows examples of test current command values ​​and test voltage command values. [Figure 8] This figure shows other examples of test current command values ​​and test voltage command values. [Figure 9] This flowchart shows other examples of the control device's operation. [Figure 10] This flowchart shows other examples of the control device's operation. [Figure 11] This figure shows an example of the hardware resources of a control device. [Figure 12] This figure shows another example of the hardware resources of a control device. [Modes for carrying out the invention]

[0009] A detailed explanation follows, with reference to the drawings. Repetitive explanations will be simplified or omitted as appropriate. In each drawing, the same reference numerals indicate the same or corresponding parts.

[0010] Embodiment 1. Figure 1 shows an example of an elevator system 1 equipped with a control device 20 in Embodiment 1. The elevator system 1 shown in Figure 1 comprises a car 2 and a counterweight 3. The car 2 moves up and down in a hoistway 4. The hoistway 4 is a space formed in a building 5. The hoistway 4 is formed to penetrate each floor of the building 5. As an example, landings 6 where the car 2 can stop are provided on each floor of the building 5.

[0011] The elevator car 2 and counterweight 3 are suspended from the hoistway 4 by rope 7. Rope 7 is wrapped around the drive sheave 9 of the hoisting machine 8. The hoisting machine 8 is controlled by a control panel 10. That is, the hoisting machine 8 rotates the drive sheave 9 based on commands from the control panel 10. When the drive sheave 9 rotates, rope 7 moves in a direction corresponding to the direction of rotation of the drive sheave 9. The elevator car 2 moves up or down in the hoistway 4 depending on the direction in which rope 7 moves. The counterweight 3 moves up and down in the hoistway 4 in the opposite direction to the direction in which the elevator car 2 moves.

[0012] Figure 1 shows an example where a machine room 11 is located above the hoistway 4. The hoisting machine 8 and control panel 10 are located in the machine room 11. If there is no machine room 11 in the building 5, the hoisting machine 8 and control panel 10 may be located in the hoistway 4. The control panel 10 not only controls the hoisting machine 8 but also controls the overall operation of the elevator system 1.

[0013] The car 2 includes a car compartment 12, a door 13, a control device 20, and a motor 21. An entrance for users to get on and off is formed in the car compartment 12. The door 13 opens and closes the entrance by moving horizontally with respect to the car compartment 12. The door 13 is driven by a motor 21. The motor 21 is controlled by the control device 20. That is, the control device 20 is a device for controlling the door 13. Specifically, the control device 20 controls the position and moving speed of the door 13, etc.

[0014] Figure 1 shows a state where the car 2 is stopped at a landing 6 on a certain floor. While the car 2 is moving, the door 13 is in a fully closed state. When the car 2 moving from another floor stops at the landing 6, the control device 20 opens the door 13. The door 14 provided at the landing 6 is interlocked with the door 13 if the car 2 is stopped at that landing 6. Users get on and off the car 2 when the door 13 is fully open. While the users are getting on and off, the control device 20 maintains the fully open state of the door 13. After that, the control device 20 closes the door 13.

[0015] Figure 2 is a diagram showing an example of the control device 20. The motor 21 is a motor that is rotationally driven by, for example, three-phase alternating current. The motor 21 includes coils corresponding to each phase of the three-phase alternating current. That is, the motor 21 includes a U-phase coil, a V-phase coil, and a W-phase coil. The rotational position θ, rotational speed, rotational torque, etc. of the motor 21 are controlled by the supplied electric power.

[0016] As shown in Figure 2, the motor 21 includes a rotation sensor 22. The rotation sensor 22 detects the rotational position θ of the motor 21. An encoder or a resolver is adopted as the rotation sensor 22. Other types of sensors may be adopted as the rotation sensor 22. The information on the rotational position θ detected by the rotation sensor 22 is input to the control device 20. The information on the rotational position θ is used in the control device 20 for rotational position control and current control reference, etc.

[0017] The rotation sensor 22 may also detect the position of the door 13 based on the rotation position θ of the motor 21. The information on the position of the door 13 detected by the rotation sensor 22 is input to the control panel 10. The control panel 10 uses the information on the position of the door 13 to determine the acceleration position and deceleration position of the door 13, etc.

[0018] The control device 20 includes a current sensor 23, a door state detection unit 24, a current coordinate transformation unit 25, a current command unit 26, a voltage command unit 27, a voltage coordinate transformation unit 28, a power conversion unit 29, a resistance estimation unit 30, a temperature estimation unit 31, a protection control unit 32, and a voltage estimation unit 33. The equipment for realizing these functions of the control device 20 may be housed in a single enclosure or divided into multiple enclosures.

[0019] The current sensor 23 detects the value of the current flowing through each phase of the motor 21. Specifically, the current sensor 23 detects the value of the current flowing through the U phase, the V phase, and the W phase of the motor 21. Hereinafter, the value of the current flowing through the U phase detected by the current sensor 23 will also be referred to as the actual current value Iu. The value of the current flowing through the V phase detected by the current sensor 23 will also be referred to as the actual current value Iv. The value of the current flowing through the W phase detected by the current sensor 23 will also be referred to as the actual current value Iw. Only two of the actual current values ​​Iu, Iv, and Iw may be detected by the current sensor 23. The actual current values ​​Iu, Iv, and Iw may be used as feedback signals for current control of the motor 21 in the control device 20.

[0020] The door state detection unit 24 detects the state of the door 13. The states of the door 13 detected by the door state detection unit 24 include, for example, a fully open state, a fully closed state, an operating state, and other states. The operating state includes an open operation state and a closed operation state. The open operation state is the state in which the door 13 is moving in the direction of opening. For example, the period from when a fully closed door 13 begins to open until it reaches the fully open state is the open operation state. The closed operation state is the state in which the door 13 is moving in the direction of closing. For example, the period from when a fully open door 13 begins to close until it reaches the fully closed state is the closed operation state.

[0021] The method by which the door state detection unit 24 detects the state of the door 13 may be any method. For example, the door state detection unit 24 performs state detection based on the rotation position θ detected by the rotation sensor 22. The door state detection unit 24 may also perform state detection using a sensor attached to the fully closed position and a sensor attached to the fully open position.

[0022] The current coordinate transformation unit 25 receives the value of the rotational position θ detected by the rotation sensor 22. The current coordinate transformation unit 25 also receives the actual current values ​​Iu, Iv, and Iw detected by the current sensor 23. Based on the rotational position θ, the current coordinate transformation unit 25 transforms the coordinate system of the actual current values ​​Iu, Iv, and Iw into the dq coordinate system. That is, based on the input rotational position θ and the actual current values ​​Iu, Iv, and Iw, the current coordinate transformation unit 25 calculates and outputs the corresponding actual current value Id of the d axis and the actual current value Iq of the q axis.

[0023] The current command unit 26 includes the functions of the motor 21's control system. These functions include, for example, a position control system and a speed control system. The current command unit 26 generates current command values ​​to control the current flowing through the motor 21. These current command values ​​are generated based, for example, on commands from the control panel 10, signals from the motor 21's position control system, signals from the motor 21's speed control system, etc. In the example shown in Figure 2, the current command unit 26 generates current command values ​​expressed in a dq coordinate system. That is, the current command unit 26 generates and outputs a current command value Id* for the d axis and a current command value Iq* for the q axis.

[0024] The actual current value Iq of the q-axis is a current value related to the rotational torque of the motor 21. When the current command unit 26 controls the door 13 to open and maintain the door 13 in a fully open state, it generates a current command value Iq* such that the motor 21 generates torque in the direction of opening the door 13. When the current command unit 26 controls the door 13 to close and maintain the door 13 in a fully closed state, it generates a current command value Iq* such that the motor 21 generates torque in the direction of closing the door 13.

[0025] The actual current value Id of the d-axis is a current value that does not contribute to rotational torque. The current command unit 26 sets the current command value Id* to 0 when performing control to open the door 13, close the door 13, maintain the door 13 in a fully open state, or maintain the door 13 in a fully closed state. However, when the motor 21 is operated in a specific operating range of high speed and high torque to open or close the door 13, the current command value Id* may be set to a value other than 0 in order to perform flux weakening control. However, even when the motor 21 is operating in the said operating range, the current command unit 26 sets the current command value Id* to 0 when performing control to maintain the door 13 in a fully open or fully closed state.

[0026] The voltage command unit 27 controls the current flowing through the motor 21. The voltage command unit 27 generates a voltage command value so that the value of the current flowing through the motor 21 follows the current command value from the current command unit 26. For example, the voltage command unit 27 generates and outputs a voltage command value for controlling the applied voltage to the motor 21, expressed in a dq coordinate system, based on the actual current value and the current command value. In the example shown in Figure 2, the voltage command unit 27 may also include the function of a subtractor 34.

[0027] As an example, the voltage command unit 27 receives the actual current values ​​Id and Iq calculated by the current coordinate transformation unit 25. The voltage command unit 27 also receives the current command values ​​Id* and Iq* generated by the current command unit 26. The voltage command unit 27 calculates and outputs the d-axis voltage command value Vd* and the q-axis voltage command value Vq* such that the actual current values ​​Id and Iq follow the current command values ​​Id* and Iq*. For example, the voltage command unit 27 performs control calculations so that the actual current values ​​Id and Iq match the current command values ​​Id* and Iq*. The control performed by the voltage command unit 27 can be realized by any control such as PID control.

[0028] The voltage coordinate transformation unit 28 receives the value of the rotational position θ detected by the rotation sensor 22. The voltage command values ​​Vd* and Vq* generated by the voltage command unit 27 are also received by the voltage coordinate transformation unit 28. Based on the rotational position θ, the voltage coordinate transformation unit 28 transforms the coordinate system of the voltage command values ​​Vd* and Vq* into the UVW coordinate system. That is, based on the input rotational position θ and the voltage command values ​​Vd* and Vq*, the voltage coordinate transformation unit 28 calculates and outputs the corresponding U-phase voltage command value Vu*, V-phase voltage command value Vv*, and W-phase voltage command value Vw*. The voltage coordinate transformation unit 28 may also convert the voltage command values ​​Vu*, Vv*, and Vw* into duty cycles and output them according to the design values ​​of the power conversion unit 29.

[0029] The power conversion unit 29 is electrically connected to the motor 21. The current sensor 23 is installed between the power conversion unit 29 and the motor 21. The power conversion unit 29 is supplied with power from an operating power supply (not shown). In the following, as shown in Figure 2, the voltage value of the power supplied to the power conversion unit 29 from the operating power supply will also be referred to as the bus voltage value Vdc.

[0030] The power conversion unit 29 is an amplifier that supplies power to control the rotation of the motor 21. For example, the power conversion unit 29 has the function of a PWM inverter. The power conversion unit 29 generates a corresponding PWM signal by comparing the voltage command values ​​Vu*, Vv*, and Vw* from the voltage coordinate conversion unit 28 with other carriers. The power conversion unit 29 uses the generated PWM signal as a switching command for the switching elements of the inverter. Based on this switching command, the power conversion unit 29 converts power from the operating power supply and supplies power to the motor 21.

[0031] In addition to the control processing of the motor 21, the control device 20 performs temperature estimation processing. The temperature estimation processing is a process for estimating the temperature of the coils included in the motor 21. Hereafter, the coils included in the motor 21 will also be simply referred to as coil C. The temperature estimation processing includes resistance estimation processing and voltage estimation processing. The resistance estimation processing is a process for estimating the electrical resistance value of the motor 21. The voltage estimation processing is a process for estimating the bus voltage value supplied to the power conversion unit 29. The control device 20 may further perform overheat protection processing after the temperature estimation processing.

[0032] The resistance estimation unit 30, the temperature estimation unit 31, and the voltage estimation unit 33 are functions provided in the control device 20 for performing temperature estimation processing. The protection control unit 32 is a function provided in the control device 20 for performing overheat protection processing.

[0033] Specifically, the resistance estimation unit 30 estimates the electrical resistance value R^ of the motor 21. That is, R^ represents the estimated value of electrical resistance. The resistance estimation unit 30 estimates the electrical resistance value R^ when the door state detection unit 24 detects that the door 13 is in a fully open or fully closed state.

[0034] The resistance estimation unit 30 receives the actual current value Id calculated by the current coordinate transformation unit 25. The resistance estimation unit 30 also receives the voltage command value Vd* generated by the voltage command unit 27. Based on the input actual current value Id and voltage command value Vd*, the resistance estimation unit 30 estimates the electrical resistance value R^. As an example, the resistance estimation unit 30 estimates the total electrical resistance value of an electrical circuit consisting of a U-phase coil, a V-phase coil, and a W-phase coil as the electrical resistance value R^.

[0035] The voltage estimation unit 33 estimates the bus voltage value Vdc^ supplied to the power conversion unit 29, i.e., the inverter for driving the motor 21. That is, Vdc^ represents the estimated bus voltage. The voltage estimation unit 33 estimates the bus voltage value Vdc^ when the door state detection unit 24 detects that the door 13 is in an operating state, i.e., in an open or closed state.

[0036] The voltage estimation unit 33 receives the actual current values ​​Id and Iq calculated by the current coordinate transformation unit 25. The voltage estimation unit 33 receives the voltage command value Vq* generated by the voltage command unit 27. The voltage estimation unit 33 receives the rotational angular velocity ω based on the rotational position θ detected by the rotation sensor 22. The voltage estimation unit 33 estimates the bus voltage value Vdc^ based on the input actual current values ​​Id and Iq, the voltage command value Vq*, and the rotational angular velocity ω.

[0037] The temperature estimation unit 31 estimates the temperature T of the coil C included in the motor 21. The temperature estimation unit 31 receives the electrical resistance value R^ estimated by the resistance estimation unit 30. The temperature estimation unit 31 receives the bus voltage value Vdc^ estimated by the voltage estimation unit 33. The temperature estimation unit 31 estimates the temperature T of the coil C based on the input electrical resistance value R^ and bus voltage value Vdc^. Specifically, the temperature estimation unit 31 corrects the electrical resistance value R^ using the bus voltage value Vdc^. The temperature estimation unit 31 estimates the temperature T of the coil C based on the corrected electrical resistance value R^.

[0038] The protection control unit 32 receives the temperature T value estimated by the temperature estimation unit 31. Based on the temperature T estimated by the temperature estimation unit 31, the protection control unit 32 determines whether or not to perform protection control for coil C.

[0039] The following explains in detail the principles of the functions of the control device 20. First, we will explain the principle by which the electrical resistance value R^ is calculated in the resistance estimation process.

[0040] In general, equations (1) and (2) hold true for motor 21. Equation (1) is the voltage equation for the d axis. Equation (2) is the voltage equation for the q axis.

[0041]

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[0042]

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[0043] R is the total resistance of the coils included in motor 21. Ld is the inductance of the d axis. Lq is the inductance of the q axis. ω is the electrical angular velocity. φ is the induced voltage constant.

[0044] If door 13 is fully open or fully closed, the rotational position θ of motor 21 does not change over time. Therefore, the electrical angular velocity ω is 0. In this case, equation (1) can be interpreted as equation (3). Equation (2) can be interpreted as equation (4).

[0045]

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[0046]

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[0047] From equations (3) and (4), if the door 13 is fully open or fully closed, the resistance value R can be calculated based on Ohm's law using the pairs of Vd and Id or Vq and Iq.

[0048] The values ​​used when calculating the resistance value R require reliability. In the control device 20, the actual current values ​​Id and Iq are calculated by the current coordinate transformation unit 25 based on the actual current values ​​Iu, Iv, and Iw and the rotational position θ. The actual current values ​​Iu, Iv, and Iw and the rotational position θ are measured values. That is, since the actual current values ​​Id and Iq are calculated based on measured values, they can be considered accurate values.

[0049] On the other hand, the applied voltage values ​​Vd and Vq are difficult to measure in practice. Therefore, in the temperature estimation process, the voltage command values ​​Vd* and Vq* generated by the voltage command unit 27 are used instead of the applied voltage values ​​Vd and Vq. However, if the voltage command values ​​Vd* and Vq* are directly applied to equation (3) or (4), the estimated resistance value R may contain various estimation errors.

[0050] For example, if there is a design difference between the bus voltage value supplied from the power source to the power conversion unit 29 and the voltage value used as the design value in the motor 21 control system, this design difference may cause errors between the voltage command values ​​Vd* and Vq* and the voltage value actually applied to the motor 21. Furthermore, this design difference may cause errors in the dead time correction performed by the power conversion unit 29.

[0051] The voltage command unit 27 generates voltage command values ​​Vd* and Vq* in such a way that various errors caused by the design difference are reduced or eliminated. Specifically, the voltage command unit 27 calculates and generates voltage command values ​​Vd* and Vq* to absorb the difference between the bus voltage value supplied to the power conversion unit 29 and the voltage value used as the design value. The voltage command unit 27 calculates and generates voltage command values ​​Vd* and Vq* to compensate for the dead time correction error caused by the design difference. However, even with such calculations, errors still occur between the voltage command values ​​Vd* and Vq* and the voltage value actually applied.

[0052] This error can be divided into additive and multiplicative errors. Additive errors include the dead time correction error. Multiplicative errors include the error between the design value and the actual voltage value of the bus voltage in the duty cycle calculation.

[0053] For example, in order to correct the error between the design value of the bus voltage and the actual voltage value, a voltage sensor for measuring the bus voltage value is required. However, due to manufacturing cost constraints or space constraints on the circuit board, it may not be possible to provide such a voltage sensor in the control device 20. In such cases, the actual voltage value cannot be used in the calculation of the duty cycle, and the design value of the bus voltage must be used. Equation (5) shows the relationship between the voltage command value Vd* and the applied voltage value Vd. Equation (6) shows the relationship between the voltage command value Vq* and the applied voltage value Vq.

[0054]

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[0055]

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[0056] γ is a coefficient representing the multiplicative error. ΔVd is the additive error on the d-axis. ΔVq is the additive error on the q-axis.

[0057] In the example shown in this embodiment, in order to suppress the deterioration of the accuracy of the estimated value due to errors, the difference between the voltage command value and the difference between the actual current value is used in the resistance estimation process. For example, equation (7) is used in the resistance estimation process.

[0058]

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[0059] The difference ΔV is the change in the voltage command value on the d axis or the change in the voltage command value on the q axis. The difference ΔI is the change in the actual current value on the d axis or the change in the actual current value on the q axis. The difference ΔV is the difference between the two voltage command values. Therefore, the difference ΔV is the value after the additive errors ΔVd and ΔVq that exist between the voltage command values ​​Vd* and Vq* and the actual applied voltage values ​​have been canceled out. It is preferable to use such a value in the resistance estimation process.

[0060] To calculate the difference ΔV, at least two sets of voltage command values ​​Vd* and Vq* are required. Three or more sets of voltage command values ​​Vd* and Vq* may be used to calculate the difference ΔV. A specific example of generating multiple sets of voltage command values ​​Vd* and Vq* will be described later. For example, by setting the q-axis current command value Iq* to a constant value and applying the voltage command values, the first value Vd1* and the second value Vd2*, and the corresponding actual current values, the first value Id1 and the second value Id2, to equation (7), equation (8) can be obtained.

[0061]

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[0062] From equation (8), the resistance estimation unit 30 can estimate the electrical resistance value R^ of the motor 21.

[0063] Next, we will explain the principle by which the bus voltage value Vdc^ is calculated in the voltage estimation process.

[0064] Using the design value Vdc* for the bus voltage and the actual bus voltage Vdc, the relationship between the applied voltage Vd and the voltage command value Vd* is expressed as shown in equation (9). The relationship between the applied voltage Vq and the voltage command value Vq* is expressed as shown in equation (10).

[0065]

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[0066]

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[0067] Vd* / Vdc* and Vq* / Vdc* are values ​​equivalent to the duty cycle. The duty cycle is calculated in the control device 20, and the voltage value applied to the motor 21 is determined by multiplying the calculation result by the actual value of the bus voltage Vdc. If the actual bus voltage value Vdc matches the design value of the bus voltage Vdc*, the applied voltage value matches the voltage command value. Solving equation (9) for the voltage command value Vd*, we can obtain the relationship between the voltage command value Vd* and the applied voltage value Vd as shown in equation (11). Solving equation (10) for the voltage command value Vd*, we can obtain the relationship between the voltage command value Vq* and the applied voltage value Vq as shown in equation (12).

[0068]

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[0069]

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[0070] Vdc / Vdc* is the coefficient γ in equations (5) and (6). Thus, the multiplicative voltage error cannot be canceled out by calculating the resistance using the voltage difference as in equation (7). For this reason, the voltage error becomes the estimation error of the resistance, i.e., the estimation error of the temperature.

[0071] As shown in equations (1) and (2), the voltage of motor 21 is expressed by a voltage equation. By substituting the applied voltage value Vd in equation (11), i.e., the actual voltage value of motor 21, into the voltage equation in equation (1), we can obtain equation (13). By substituting the applied voltage value Vq in equation (12), i.e., the actual voltage value of motor 21, into the voltage equation in equation (2), we can obtain equation (14).

[0072]

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[0073]

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[0074] Since the resistance R is unknown, it cannot be used as a parameter in the voltage estimation process. Therefore, a condition for estimating the bus voltage is that the current value is small enough that terms containing the resistance R can be ignored. In addition, the inductance L changes with the current due to the effect of magnetic saturation. For this reason, it is preferable that terms containing the inductance L can also be ignored, but this condition can also be achieved by reducing the current value. If the current value is small, equation (13) can be approximated as equation (15), and equation (14) can be approximated as equation (16).

[0075]

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[0076]

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[0077] As shown in equation (15), if the current value is small, the voltage command value Vd* is almost 0. For this reason, when the current value is small, equation (15) cannot be used in the voltage estimation process. On the other hand, if the rotational angular velocity ω of the motor 21 is large enough, the voltage command value Vq* will not be 0. For this reason, the voltage estimation unit 33 can estimate the bus voltage value Vdc^ from equation (17), which is a modified version of equation (16).

[0078]

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[0079] Furthermore, under conditions of low current, the actual q-axis voltage value of motor 21 can be expressed as the product of the rotational angular velocity ω and the induced voltage constant φ. In the following, this value will also be referred to as the theoretically calculated q-axis voltage value ωφ.

[0080] Next, with reference to Figures 3 to 8, the temperature estimation process performed by the control device 20 will be explained in detail. Figure 3 is a flowchart showing an example of the operation of the control device 20. The control device 20 determines whether or not the door 13 has started to open (S001). When the state of the door 13 detected by the door state detection unit 24 changes from the fully closed state to the open state, it is determined to be Yes in S001.

[0081] If the result in S001 is determined to be Yes, the voltage estimation process is started (S002). In the voltage estimation process, the voltage estimation unit 33 estimates the bus voltage value Vdc^.

[0082] Furthermore, if Yes is determined in S001, it is determined whether or not the door 13 is fully open (S003). If the door state detection unit 24 detects that the door 13 is fully open after Yes is determined in S001, then Yes is determined in S003. The voltage estimation process continues until Yes is determined in S003. Once Yes is determined in S003, the voltage estimation process ends.

[0083] The process shown in S001 to S003 in Figure 3 illustrates an example where the voltage estimation process is performed while the door 13 is being opened. The voltage estimation process may also be performed while the door 13 is being closed. In this case, it is determined in S001 whether or not the door 13 has started closing. In S003, it is determined whether or not the door 13 is fully closed. The voltage estimation process continues after it is determined to be Yes in S001 until it is determined to be Yes in S003.

[0084] Figure 4 is a flowchart showing a preferred example of the voltage estimation process. Figure 4 shows an example of the process performed at S002 in Figure 3. As described above, it is preferable to estimate the bus voltage value Vdc^ when the rotational angular velocity ω of the motor 21 is relatively large and the value of the current flowing through the motor 21 is small.

[0085] In the voltage estimation process, the voltage estimation unit 33 determines whether the rotational angular velocity ω of the motor 21 is greater than or equal to a first reference value Th1 (S101). The first reference value Th1 is set in advance. If the rotational angular velocity ω is greater than or equal to the first reference value Th1, S101 determines Yes.

[0086] Note that the sign of the rotational angular velocity ω differs when the door 13 is opening and when it is closing. Considering the case when the door 13 is closing, in S101, if the absolute value of the rotational angular velocity ω is greater than or equal to the first reference value Th1, the result is determined to be Yes. In order to make the determination in S101, different values ​​may be used as the first reference value Th1 when the door 13 is opening and when it is closing.

[0087] If the result in S101 is Yes, the voltage estimation unit 33 determines whether the value of the current flowing through the motor 21 is less than or equal to the second reference value Th2 (S102). The second reference value Th2 is set in advance. If the value of the current flowing through the motor 21 is less than or equal to the second reference value Th2, the result in S102 is Yes.

[0088] Note that the sign of the current flowing through the motor 21 differs depending on whether the door 13 is opening or closing. Considering the case where the door 13 is closing, in S102, if the absolute value of the current is less than or equal to the second reference value Th2, the result is determined to be Yes. In order to make the determination in S102, different values ​​may be used as the second reference value Th2 when the door 13 is opening or closing.

[0089] If the result in S102 is "Yes", the bus voltage value Vdc^ is estimated (S103). That is, the voltage estimation unit 33 calculates the bus voltage value Vdc^ using equation (17) when the absolute value of the rotational angular velocity ω is greater than or equal to the first reference value Th1 and the absolute value of the current flowing through the motor 21 is less than or equal to the second reference value Th2.

[0090] In the example shown in Figure 4, if the absolute value of the rotational angular velocity ω is not greater than or equal to the first reference value Th1, the result is determined as No in S101. If the result is No in S101, the voltage estimation unit 33 does not perform the estimation calculation of the bus voltage value Vdc^. Also, if the absolute value of the current flowing through the motor 21 is not less than or equal to the second reference value Th2, the result is determined as No in S102. If the result is No in S102, the voltage estimation unit 33 does not perform the estimation calculation of the bus voltage value Vdc^.

[0091] Figure 5 is a diagram illustrating the function of the voltage estimation unit 33. The upper part of Figure 5 shows the time change of the rotational angular velocity ω of the motor 21 when the door 13 is opened or closed. The middle part of Figure 5 shows the time change of the actual current value Id on the d axis when the door 13 is opened or closed. The lower part of Figure 5 shows the time change of the actual current value Iq on the q axis when the door 13 is opened or closed.

[0092] As shown in Figure 5, the rotational angular velocity ω increases after the opening or closing operation of the door 13 begins, and then decreases thereafter. The actual current value Id on the d axis is controlled to 0 when the door 13 is opening or closing, if the motor 21 is a typical permanent magnet synchronous motor. The actual current value Iq on the q axis is a value equivalent to the torque required for the rotational angular velocity ω to follow the command value.

[0093] The estimation conditions for calculating the bus voltage value Vdc^ are met when both the first condition concerning the rotational angular velocity ω and the second condition concerning the current flowing through the motor 21 are satisfied. The first condition is that the rotational angular velocity ω is greater than or equal to the first reference value Th1, that is, the condition for ωφ to be sufficiently large in the voltage equation of the motor 21. The second condition is that the actual current values ​​Id and Iq are each less than or equal to the second reference value Th2, that is, the condition for the voltage equation of the motor 21 to no longer be affected by the resistance value R and inductance L.

[0094] The voltage estimation unit 33 estimates the bus voltage value Vdc^ based on equation (17) when the first and second conditions are met. The estimation based on equation (17) uses the q-axis voltage command value Vq* and the theoretically calculated q-axis voltage value ωφ calculated based on the q-axis voltage equation of the motor 21. More specifically, the ratio of the theoretically calculated q-axis voltage value ωφ to the q-axis voltage command value Vq* is used in the estimation. That is, in S103 of Figure 4, the voltage estimation unit 33 obtains the bus voltage value Vdc^ by multiplying the rotational angular velocity ω by the induced voltage constant φ and the design value of the bus voltage Vdc*, and then dividing the result by the voltage command value Vq*.

[0095] If the result in S003 in Figure 3 is "Yes", the resistance estimation process starts (S004). Note that the resistance estimation process starts only if the door 13 is fully open or fully closed. Figure 3 shows an example where the resistance estimation process is performed when the door 13 is fully open. As will be explained in more detail later, the resistance estimation process may also be performed when the door 13 is fully closed.

[0096] As described above, the resistance estimation unit 30 can estimate the electrical resistance value R^ of the motor 21 from equation (8). Multiple sets of voltage command values ​​are required to estimate the electrical resistance value R^ using equation (8). Therefore, when the resistance estimation process is started, the current command unit 26 generates multiple sets of current command values ​​(S005). These current command values ​​are generated to estimate the temperature T of the coil C. Hereinafter, these current command values ​​will also be referred to as test current command values.

[0097] When resistance estimation processing is performed when door 13 is fully open, the current command unit 26 generates multiple sets of test current command values ​​in S005 that maintain the fully open state of door 13. When resistance estimation processing is performed when door 13 is fully closed, the current command unit 26 generates multiple sets of test current command values ​​in S005 that maintain the fully closed state of door 13.

[0098] Each test current command value includes a d-axis test current command value Id* and a q-axis test current command value Iq*. Each test current command value Iq* included in multiple sets of test current command values ​​is of the same magnitude. Each test current command value Id* included in multiple sets of test current command values ​​is of a different magnitude. That is, the current command unit 26 generates multiple sets of test current command values ​​Id* and Iq* in which the test current command value Iq* is fixed to a constant value and the test current command value Id* is set to different values. The reason for fixing the test current command value Iq* to a constant value is that changing the test current command value Iq* may make it impossible to maintain the fully open or fully closed state of the door 13. The current command unit 26 generates one set of test current command values ​​Id* and Iq* in sequence.

[0099] Furthermore, if the motor 21 has a surface permanent magnet (SPM), no rotational torque is generated even if a d-axis current is flowing. On the other hand, if the motor 21 has an interior permanent magnet (IPM), reluctance torque is generated when a d-axis current flows. Reluctance torque is often relatively smaller than magnet torque, and its effect is small. However, if the motor 21 has an interior permanent magnet, the d-axis test current command value Id* may be generated taking into account the effect of reluctance torque.

[0100] When multiple sets of test current command values ​​Id* and Iq* are generated in S005, the voltage command unit 27 generates corresponding sets of voltage command values ​​Vd* and Vq*. Hereinafter, these voltage command values ​​will also be referred to as test voltage command values. The motor 21 operates according to the generated test voltage command values ​​Vd* and Vq*. The actual current values ​​Iu, Iv, and Iw at this time are detected by the current sensor 23. The resistance estimation unit 30 estimates the electrical resistance value R^ from equation (8) based on the test voltage command value Vq* from the voltage command unit 27 and the actual current values ​​Id and Iq from the current coordinate transformation unit 25 (S006).

[0101] Figure 6 is a flowchart showing a preferred example of the resistance estimation process. Figure 7 shows a specific example of the processes performed in S005 and S006 of Figure 3. As described above, the resistance estimation process generates multiple sets of test current command values. For example, the current command unit 26 generates multiple sets of test current command values ​​in which the current value on the d axis is not zero. Below, we will describe an example in which three sets of test current command values ​​with different values ​​are generated sequentially at regular time intervals.

[0102] When the resistance estimation process starts in S004, the current command unit 26 generates the first set of test current command values, namely the first test current command value Id1* for the d axis and the first test current command value Iq1* for the q axis (S201). The voltage command unit 27 generates the first test voltage command value Vd1* for the d axis, which corresponds to the first test current command value Id1*. The voltage command unit 27 generates the first test voltage command value Vq1* for the q axis, which corresponds to the first test current command value Iq1*. As a result, the resistance estimation unit 30 obtains the first test voltage command value Vd1* from the voltage command unit 27.

[0103] The power conversion unit 29 supplies power to the motor 21 based on the first test voltage command values ​​Vd1* and Vq1*. As a result, the current sensor 23 detects the actual current values ​​Iu1, Iv1, and Iw1 corresponding to the first test voltage command values ​​Vd1* and Vq1*, and the current coordinate conversion unit 25 outputs the corresponding first actual current value Id1 for the d axis and the first actual current value Iq1 for the q axis. The resistance estimation unit 30 obtains the first actual current value Id1, which is the current value of the motor 21 following the first test current command value Id1*, from the current coordinate conversion unit 25 (S202).

[0104] Next, the current command unit 26 generates a second set of test current command values, namely the second test current command value Id2* for the d axis and the second test current command value Iq2* for the q axis (S203). The second test current command value Id2* is a value of a different magnitude than the first test current command value Id1*. The voltage command unit 27 generates the second test voltage command value Vd2* for the d axis, which corresponds to the second test current command value Id2*. The voltage command unit 27 generates the second test voltage command value Vq2* for the q axis, which corresponds to the second test current command value Iq2*. As a result, the resistance estimation unit 30 obtains the second test voltage command value Vd2* from the voltage command unit 27.

[0105] The power conversion unit 29 supplies power to the motor 21 based on the second test voltage command values ​​Vd2* and Vq2*. As a result, the current sensor 23 detects the actual current values ​​Iu2, Iv2, and Iw2 corresponding to the second test voltage command values ​​Vd2* and Vq2*, and the current coordinate conversion unit 25 outputs the corresponding second actual current value Id2 for the d axis and the second actual current value Iq2 for the q axis. The resistance estimation unit 30 obtains the second actual current value Id2, which is the current value of the motor 21 following the second test current command value Id2*, from the current coordinate conversion unit 25 (S204).

[0106] Next, the current command unit 26 generates a third set of test current command values, namely the third test current command value Id3* for the d axis and the third test current command value Iq3* for the q axis (S205). The third test current command value Id3* is a value of a different magnitude from the first test current command value Id1* and the second test current command value Id2*. The voltage command unit 27 generates the third test voltage command value Vd3* for the d axis, which corresponds to the third test current command value Id3*. The voltage command unit 27 generates the third test voltage command value Vq3* for the q axis, which corresponds to the third test current command value Iq3*. As a result, the resistance estimation unit 30 obtains the third test voltage command value Vd3* from the voltage command unit 27.

[0107] The power conversion unit 29 supplies power to the motor 21 based on the third test voltage command values ​​Vd3* and Vq3*. As a result, the current sensor 23 detects the actual current values ​​Iu3, Iv3, and Iw3 corresponding to the third test voltage command values ​​Vd3* and Vq3*, and the current coordinate conversion unit 25 outputs the corresponding third actual current value Id3 for the d axis and the third actual current value Iq3 for the q axis. The resistance estimation unit 30 obtains the third actual current value Id3, which is the current value of the motor 21 following the third test current command value Id3*, from the current coordinate conversion unit 25 (S206).

[0108] The resistance estimation unit 30 estimates the electrical resistance value R^ from equation (8) based on the information obtained in S202, S204, and S206 (S207).

[0109] Figure 7 shows examples of test current command values ​​and test voltage command values. The upper part of Figure 7 shows an example of the d-axis test current command value Id* generated by the current command unit 26. Note that if the actual current value Id quickly follows the test current command value Id*, the upper part of Figure 7 also shows an example of the actual current value Id. The lower part of Figure 7 shows an example of the d-axis test voltage command value Vd* generated by the voltage command unit 27.

[0110] In the example shown in Figure 7, the current command unit 26 outputs a pulse wave shape as the test current command value Id* on the d axis. Specifically, of the three pulse outputs shown in the upper part of Figure 7, the left pulse output corresponds to the first test current command value Id1*, the center pulse output corresponds to the second test current command value Id2*, and the right pulse output corresponds to the third test current command value Id3*. The current command unit 26 intermittently generates pulse outputs of different magnitudes as the test current command value Id* on the d axis. The voltage command unit 27 outputs a pulse wave shape as the test voltage command value Vd* on the d axis.

[0111] The width of each pulse output is set to a width greater than or equal to the settling time. The settling time is the time required for the actual current value Id to follow and settle in relation to the current command value Id*. The settling time is determined by the design of the control gain of the current command unit 26. The settling time is preset.

[0112] In the example shown in Figure 7, the second test current command value Id2* is generated after the first test current command value Id1* is generated. There is a period of time when the current command value Id* on the d axis is 0 between the end of generation of the first test current command value Id1* and the start of generation of the second test current command value Id2*. Also, the third test current command value Id3* is generated after the second test current command value Id2* is generated. There is a period of time when the current command value Id* on the d axis is 0 between the end of generation of the second test current command value Id2* and the start of generation of the third test current command value Id3*.

[0113] Since the first test current command value Id1*, the second test current command value Id2*, and the third test current command value Id3* are generated in order, the first test voltage command value Vd1*, the second test voltage command value Vd2*, and the third test voltage command value Vd3* are also generated in order. Similarly, the first actual current value Id1, the second actual current value Id2, and the third actual current value Id3 are detected in order.

[0114] Furthermore, as the actual current value Id in the d-axis increases, the amount of heat generated in coil C also increases. In the example shown in Figure 7, the voltage applied to motor 21 becomes pulsed, which can suppress this amount of heat generation.

[0115] Figure 8 shows other examples of test current command values ​​and test voltage command values. The upper part of Figure 8 shows an example of the d-axis test current command value Id* generated by the current command unit 26. Note that if the actual current value Id quickly follows the test current command value Id*, the upper part of Figure 8 also shows an example of the actual current value Id. The lower part of Figure 8 shows an example of the d-axis test voltage command value Vd* generated by the voltage command unit 27.

[0116] In the example shown in Figure 8, the current command unit 26 outputs a ramp-shaped waveform as the test current command value Id* on the d axis. That is, the current command unit 26 outputs a waveform that continuously increases from 0 as the test current command value Id* on the d axis. The example shown in Figure 8 can be applied when heat generation of coil C is not a problem, and when the tracking lag between the actual current value Id and the test current command value Id* is not a problem.

[0117] The method for generating the d-axis test current command value Id* is not limited to the examples shown in Figure 7 and Figure 8.

[0118] As shown in equation (8), the electrical resistance R^ is estimated by dividing the change in the d-axis test voltage command value Vd*, which is changed by the d-axis test current command value Id*, by the change in the current flowing through the motor 21, which is changed by the d-axis test current command value Id*. As an example, the change in the test voltage command value can be calculated as the difference between the first test voltage command value Vd1* and the second test voltage command value Vd2*. The change in current can be calculated as the difference between the first actual current value Id1 and the second actual current value Id2.

[0119] As shown in the examples in Figure 7 and Figure 8, when three test current command values ​​Id*, namely the first test current command value Id1*, the second test current command value Id2*, and the third test current command value Id3*, are generated, it is possible to derive three values ​​as resistance values ​​R. That is, from equation (8), the following three resistance values ​​R can be calculated. R = (Vd2* - Vd1*) / (Id2 - Id1) R = (Vd3* - Vd2*) / (Id3 - Id2) R = (Vd1* - Vd3*) / (Id1 - Id3)

[0120] If multiple resistance values ​​R can be calculated, in S207, the resistance estimation unit 30 may estimate the average of the multiple calculated resistance values ​​R as the electrical resistance value R^. To ensure safer operation, in S207, the resistance estimation unit 30 may estimate the largest of the multiple calculated resistance values ​​R as the electrical resistance value R^.

[0121] Furthermore, filtering may be applied to the current and voltage when calculating the electrical resistance value R^. This suppresses high-frequency noise contained in the current and voltage values, improving the accuracy of the estimation of the electrical resistance value R^. If filtering is performed, it is necessary to apply filtering with the same cutoff frequency. This is to ensure that the temporal correspondence between the current and voltage values ​​is matched. After filtering is performed and multiple resistance values ​​R are calculated, the average value of the calculated multiple resistance values ​​R may be estimated as the electrical resistance value R^.

[0122] When the electrical resistance value R^ is estimated in S006 in Figure 3, a process to correct the electrical resistance value R^ estimated in S006 is initiated. The temperature estimation unit 31 corrects the electrical resistance value R^ estimated in S006 using the bus voltage value Vdc^ estimated in S002 (S007).

[0123] As shown in equation (7), by performing calculations using the voltage difference ΔV, the effect of additive errors can be eliminated from the electrical resistance value R^ estimated by the resistance estimation unit 30. However, the effect of multiplicative errors remains in the electrical resistance value R^ estimated by the resistance estimation unit 30. Therefore, when the temperature T of coil C is calculated based on this electrical resistance value R^, the result will include errors caused by multiplicative errors. The temperature estimation unit 31 suppresses this error by using the bus voltage value Vdc^ estimated in S002.

[0124] Substituting equation (5) into equation (8) and rearranging, we obtain equation (18).

[0125]

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[0126] As shown in equation (18), the estimated electrical resistance R^ has an error equal to the ratio of the design value Vdc* of the bus voltage to the actual bus voltage value Vdc. Using the bus voltage value Vdc^ from equation (17), we can obtain equation (19). Equation (19) shows that by performing a correction using the bus voltage value Vdc^, the corrected value matches the true value of the resistance.

[0127]

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[0128] The temperature estimation unit 31 corrects the electrical resistance value R^ estimated in S006 using equation (19).

[0129] Once the electrical resistance value R^ is corrected in S007, the process of estimating the temperature T of coil C is started. The temperature estimation unit 31 estimates the temperature T of coil C using the electrical resistance value R^ corrected in S007 (S008).

[0130] As an example, the temperature estimation unit 31 estimates the temperature T based on a temperature formula model that shows the relationship between the electrical resistance of the motor 21 and the temperature of the coil C. The temperature formula model is pre-stored in the memory area of ​​the control device 20. The temperature formula model may also be created by an experiment in which the resistance of the motor 21 is measured while the temperature of the coil C is changed. The temperature formula model may also be a theoretically derived model. Equation (20) shows an example of such a temperature formula model.

[0131]

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[0132] Equation (20) shows an example of a model in which there is a linear relationship between the temperature T of coil C and the resistance R of motor 21. α and β are constants, respectively. α and β are predetermined. Equation (21) shows another example of the temperature formula model.

[0133]

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[0134] Equation (21) is the logical model of the temperature T of coil C. T0' is the reference temperature. R0 is the reference resistance of coil C at the reference temperature. Note that the temperature mathematical model may be expressed by equations other than (20) and (21). For example, the temperature mathematical model may be a function of order higher than first order.

[0135] Figure 9 is a flowchart illustrating another example of the operation of the control device 20. Figure 9 shows another example of the temperature estimation process. Specifically, Figure 9 shows an example in which the voltage estimation process is performed when the door 13 is closing. Also, Figure 9 shows an example in which the resistance estimation process is performed when the car 2 is moving. Matters not explained in detail below are the same as in the examples described above.

[0136] The control device 20 determines whether the door 13 has started closing (S301). When the state of the door 13 detected by the door state detection unit 24 changes from the fully open state to the closing state, it is determined as Yes in S301. If it is determined as Yes in S301, the voltage estimation process is started (S302). The voltage estimation process performed in S302 is the same as the voltage estimation process performed in S002. In the voltage estimation process, the voltage estimation unit 33 estimates the bus voltage value Vdc^.

[0137] Furthermore, if Yes is determined in S301, it is determined whether or not the door 13 is fully closed (S303). If the door state detection unit 24 detects that the door 13 is fully closed after Yes is determined in S301, Yes is determined in S303. The voltage estimation process continues until Yes is determined in S303. Once Yes is determined in S303, the voltage estimation process ends.

[0138] If the result in S303 is "Yes", the control device 20 determines whether or not the car 2 is moving (S304). For example, the control device 20 obtains information from the control panel 10 to determine whether or not the car 2 is moving. The determination in S304 is made based on this information. As another example, the current command unit 26 may perform the determination in S304.

[0139] If the elevator car 2 starts moving after being determined to be Yes in S303, then it is determined to be Yes in S304. If it is determined to be Yes in S304, the resistance estimation process starts (S305). While the elevator car 2 is moving, the control device 20 performs control to maintain the door 13 in a fully closed state. In the example shown in Figure 9, the resistance estimation process is performed during this time. If it is not determined to be Yes in S303, the resistance estimation process does not start. Note that the processes shown from S305 to S309 in Figure 9 are the same as the processes shown from S004 to S008 in Figure 3.

[0140] Next, the overheat protection process will be described with reference to Figure 10. Figure 10 is a flowchart showing another example of operation of the control device 20. Figure 10 shows an example of the overheat protection process performed after the temperature T of coil C has been estimated in the temperature estimation process. The overheat protection process is a process to prevent accidents such as the motor 21 burning out due to the temperature T of coil C becoming too high.

[0141] The following are possible causes for the temperature T of coil C to rise.

[0142] For example, the temperature T of coil C may rise due to an abnormality in the motor body 21. Specifically, the temperature T will rise if the bearings of motor 21 are worn out, or if motor 21 is nearing the end of its lifespan.

[0143] As another example, the temperature T of coil C may rise if the door 13 is opened and closed frequently. Specifically, the temperature T will rise if the elevator car 2 is called frequently, or if the door 13 is reversed frequently.

[0144] As another example, the temperature T of coil C may rise due to a malfunction in door 13. For instance, a malfunction in the mechanical system of door 13 increases the resistance to movement of door 13. This increase in resistance to movement of door 13 increases the rotational load on motor 21. This, in turn, causes the temperature T of coil C to rise.

[0145] As another example, the temperature T of coil C may rise if the ambient temperature, i.e., the temperature inside the elevator shaft 4, is high.

[0146] If the temperature T of coil C rises, the amount of heat generated by motor 21 will be greater than normal. If motor 21 continues to operate in this state, it may burn out.

[0147] As described above, the overheat protection process is a procedure to prevent accidents such as the motor 21 burning out, and is performed immediately after the temperature estimation process. Therefore, when the overheat protection process is initiated, the door 13 is either fully open or fully closed.

[0148] The protection control unit 32 obtains the temperature T estimated by the temperature estimation process (S401). Next, the protection control unit 32 determines whether the temperature T estimated by the temperature estimation unit 31 is equal to or greater than the third reference value (S402). The third reference value is a value used to determine whether the temperature of coil C has risen to a temperature that could lead to burnout of the motor 21. The third reference value is set in advance based on the thermal design of coil C, etc.

[0149] If the temperature T is less than the third reference value, it is determined as No in S402. If it is determined as No in S402, the drive control of the motor 21 continues (S403). For example, the voltage command unit 27 generates voltage command values ​​Vd* and Vq* based on the current command values ​​Id* and Iq* from the current command unit 26 and the actual current values ​​Id and Iq from the current coordinate transformation unit 25. In other words, normal operation continues in the elevator system 1.

[0150] If the temperature T is equal to or greater than the third reference value, the system determines "Yes" in S402. When the system determines "Yes" in S402, the voltage command unit 27 stops the drive control of the motor 21 as a protective control (S404). The voltage command unit 27 also transmits information to the control panel 10 indicating that the temperature T of coil C is equal to or greater than the third reference value. Upon receiving this information, the control panel 10 starts control to emergency stop the car 2.

[0151] Furthermore, if the drive control of motor 21 is stopped, the door 13 cannot be opened or closed. For this reason, the drive control of motor 21 may be stopped after the control to remove the passenger from car 2 has been performed. The control panel 10 may also provide information to the passenger that the service will be stopped.

[0152] In the example shown in this embodiment, the temperature estimation unit 31 corrects the electrical resistance value R^ estimated by the resistance estimation unit 30 using the bus voltage value Vdc^ estimated by the voltage estimation unit 33. Then, the temperature estimation unit 31 estimates the temperature T of coil C based on the corrected electrical resistance value R^. Therefore, the temperature T of coil C can be estimated with high accuracy.

[0153] In the example shown in this embodiment, the voltage estimation unit 33 estimates the bus voltage value Vdc^ when the door 13 is in operation, the absolute value of the rotational angular velocity ω is greater than or equal to the first reference value Th1, and the absolute value of the current flowing through the motor 21 is less than or equal to the second reference value Th2. Therefore, the bus voltage value Vdc^ can be calculated accurately using the simple equation (17).

[0154] In the example shown in this embodiment, the voltage estimation unit 33 estimates the bus voltage value Vdc^ using the q-axis voltage command value Vq* and the q-axis voltage theoretical calculation value ωφ. Furthermore, the voltage estimation unit 33 estimates the bus voltage value Vdc^ using the ratio of the q-axis voltage command value Vq* to the q-axis voltage theoretical calculation value ωφ. Therefore, the bus voltage value Vdc^ can be calculated accurately using the simplified equation (17).

[0155] In the example shown in this embodiment, the current command unit 26 generates a first test current command value and a second test current command value. The voltage command unit 27 generates a first test voltage command value corresponding to the first test current command value and a second test voltage command value corresponding to the second test current command value. Then, the resistance estimation unit 30 estimates the electrical resistance value R^ using the first test voltage command value and the second test voltage command value. In this example, suitable values ​​for estimating the electrical resistance value R^ can be adopted as the first test voltage command value and the second test voltage command value. Therefore, the electrical resistance value R^ can be estimated with high accuracy.

[0156] The current command unit 26 may generate only one new test current command value. In this case, the current command value generated immediately before the said test current command value may be considered as another test current command value, and the electrical resistance value R^ may be generated accordingly.

[0157] In the example shown in this embodiment, the current command unit 26 generates a first test current command value and a second test current command value in which the current value on the d axis is not zero. Even if the current value on the d axis changes, it has almost no effect on the open / closed state of the door 13. Therefore, even if such test current command values ​​are used, the electrical resistance value R^ can be estimated with good accuracy.

[0158] In the example shown in Figure 9, the resistance estimation process is performed while the car 2 is in motion. That is, a test current command value is generated while the car 2 is in motion. When the test current command value is generated, a d-axis current flows to the motor 21, and when a d-axis current flows, noise due to magnetostriction may be generated from the motor 21. In the example shown in Figure 9, this noise can be masked by the sound of the car 2 in motion. Therefore, it is possible to prevent passengers in the car 2 from feeling uncomfortable due to noise caused by magnetostriction.

[0159] In the example shown in this embodiment, the temperature estimation unit 31 estimates the temperature T of the coil C based on a temperature formula model. Therefore, the temperature T can be estimated with high accuracy.

[0160] In the example shown in this embodiment, when the temperature T of coil C estimated by the temperature estimation unit 31 exceeds the third reference value, the drive control of the motor 21 is stopped. Therefore, burnout of the motor 21 can be prevented, and the safety of the elevator system 1 can be improved.

[0161] The following describes other functions that the control device 20 can employ. In the examples shown below, only the differences from the examples described above will be explained in detail. The same points as in the examples described above will be omitted from the explanation.

[0162] The voltage estimation unit 33 may estimate the bus voltage value Vdc^ based on the state estimation observer without using equation (17).

[0163] In this example as well, the voltage estimation unit 33 can estimate the bus voltage value Vdc^ based on the operation flow shown in Figure 4. Specifically, the voltage estimation unit 33 estimates the bus voltage value Vdc^ when the door state detection unit 24 detects that the door 13 is in operation. Furthermore, it is preferable for the voltage estimation unit 33 to estimate the bus voltage value Vdc^ when the absolute value of the rotational angular velocity ω is greater than or equal to the first reference value Th1, and the absolute value of the current flowing through the motor 21 is less than or equal to the second reference value Th2.

[0164] As described above, the relationship between the applied voltage value Vd and the voltage command value Vd* is expressed as shown in equation (9). The relationship between the applied voltage value Vq and the voltage command value Vq* is expressed as shown in equation (10). Furthermore, the voltage estimation process requires that resistance R and inductance L are not used as parameters, i.e., that the current value is small. Under these conditions, the voltage command value on the d axis becomes approximately 0, so only the q axis will be explained below.

[0165] By replacing the bus voltage value Vdc in equation (10) with the estimated value Vdc^, we can obtain equation (22) for the estimated applied voltage Vq^.

[0166]

number

[0167] Equation (23) shows the difference between equation (10) and equation (22). If equation (23) is 0, then the estimated bus voltage Vdc^ and the actual bus voltage Vdc will be in agreement.

[0168]

number

[0169] From equation (23), equation (24) can be obtained as an example of a state estimation observer for estimating the busbar voltage value Vdc^. As described above, the actual applied voltage value Vq on the q-axis of the motor 21 can be expressed by ωφ under the condition that the current is small. Furthermore, the estimated value of the applied voltage Vq^ is as shown in equation (22).

[0170]

number

[0171] In S103, the voltage estimation unit 33 can estimate the bus voltage value Vdc^ based on the state estimation observer shown in equation (24), which uses the theoretically calculated voltage value ωφ of the q axis and the voltage command value Vq* of the q axis. In equation (24), K is the gain that determines the convergence speed of the state estimation observer. A larger gain shortens the time required for convergence, but if it is too large, oscillation will occur. Conversely, a smaller gain lengthens the time required for convergence, but the observer becomes more stable. The gain K must be set appropriately by the designer, taking into account the convergence speed and stability.

[0172] Figure 11 shows an example of the hardware resources of the control device 20. The control device 20 includes a processing circuit 40 as a hardware resource, which includes a processor 41 and memory 42. The processing circuit 40 may include multiple processors 41. The processing circuit 40 may also include multiple memory 42.

[0173] In this embodiment, the parts indicated by reference numerals 24 to 33 represent functions of the control device 20. The functions of the parts indicated by reference numerals 24 to 33 can be realized by software, firmware, or a combination of software and firmware, which are written as a program. The program is stored in memory 42. The control device 20 realizes the functions of the parts indicated by reference numerals 24 to 33 by executing the program stored in memory 42 using a processor 41 (computer).

[0174] The processor 41 is also called a CPU (Central Processing Unit), central processing unit, processing unit, arithmetic unit, microprocessor, microcomputer, or DSP. The memory 42 may include semiconductor memory, magnetic disks, flexible disks, optical disks, compact disks, minidiscs, or DVDs. Possible semiconductor memories include RAM, ROM, flash memory, EPROM, and EEPROM.

[0175] Figure 12 shows another example of the hardware resources of the control device 20. In the example shown in Figure 12, the control device 20 includes a processor 41, a memory 42, and a processing circuit 40 including dedicated hardware 43. Figure 12 shows an example in which some of the functions of the control device 20 are realized by the dedicated hardware 43. All of the functions of the control device 20 may be realized by the dedicated hardware 43. For example, of the parts indicated by reference numerals 24 to 33, only the current command unit 26 may be realized by the dedicated hardware 43. In this case, the parts indicated by reference numerals 24, 25, 27 to 33 are realized by the processor 41 (computer) executing a program stored in the memory 42. As the dedicated hardware 43, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC, an FPGA, or a combination thereof can be used. [Industrial applicability]

[0176] This disclosure can be applied to control devices that control elevator doors. [Explanation of symbols]

[0177] 1 Elevator system, 2 Car, 3 Counterweight, 4 Hoistway, 5 Building, 6 Landing, 7 Rope, 8 Hoisting machine, 9 Drive sheave, 10 Control panel, 11 Machine room, 12 Car room, 13 Door, 14 Door, 20 Control device, 21 Motor, 22 Rotation sensor, 23 Current sensor, 24 Door state detection unit, 25 Current coordinate transformation unit, 26 Current command unit, 27 Voltage command unit, 28 Voltage coordinate transformation unit, 29 Power conversion unit, 30 Resistance estimation unit, 31 Temperature estimation unit, 32 Protection control unit, 33 Voltage estimation unit, 34 Subtractor, 40 Processing circuit, 41 Processor, 42 Memory, 43 Dedicated hardware

Claims

1. A door state detection unit that detects the state of the elevator door, A voltage command unit generates a voltage command value so that the value of the current flowing through the motor that drives the door follows the current command value, When the door state detection unit detects that the door is in operation, a voltage estimation unit estimates the bus voltage value supplied to the inverter for driving the motor. When the door state detection unit detects that the door is in a fully open or fully closed state, the resistance estimation unit estimates the electrical resistance value of the motor. A temperature estimation unit estimates the temperature of a coil included in the motor by correcting the electrical resistance value estimated by the resistance estimation unit using the bus voltage value estimated by the voltage estimation unit, A control device equipped with the following features.

2. The control device according to claim 1, wherein the voltage estimation unit estimates the bus voltage value when the door state detection unit detects that the door is in operation, the absolute value of the rotational angular velocity of the motor is equal to or greater than a first reference value, and the absolute value of the current flowing through the motor is equal to or less than a second reference value.

3. The control device according to claim 1 or 2, wherein the voltage estimation unit estimates the bus voltage value using the theoretically calculated voltage value of the q-axis calculated based on the voltage equation of the q-axis of the motor and the voltage command value of the q-axis generated by the voltage command unit.

4. The control device according to claim 1 or 2, wherein the voltage estimation unit estimates the bus voltage value using the ratio of the theoretically calculated voltage value of the q axis calculated based on the voltage equation of the q axis of the motor to the voltage command value of the q axis generated by the voltage command unit.

5. The control device according to claim 1 or 2, wherein the voltage estimation unit estimates the bus voltage value based on a state estimation observer that uses a theoretically calculated voltage value of the q axis calculated based on the voltage equation of the q axis of the motor and a voltage command value of the q axis generated by the voltage command unit.

6. The system further comprises a current command unit that generates the aforementioned current command value, The current command unit generates a test current command value for estimating the temperature of the coil when the door state detection unit detects that the door is in a fully open or fully closed state. The control device according to claim 1 or 2, wherein the resistance estimation unit estimates the electrical resistance value by dividing the amount of change in the voltage command value, which has been changed by the test current command value, by the amount of change in the current flowing through the motor, which has been changed by the test current command value.

7. The current command unit generates a first test current command value and a second test current command value as the test current command values, wherein the current value of the d axis is not zero. The control device according to claim 6, wherein the magnitude of the second test current command value is different from the magnitude of the first test current command value.

8. The voltage command unit generates a first test voltage command value corresponding to the first test current command value and a second test voltage command value corresponding to the second test current command value. The control device according to claim 7, wherein the resistance estimation unit calculates the difference between the first test voltage command value and the second test voltage command value as the amount of change in the voltage command value, and calculates the difference between the current value of the motor following the first test current command value and the current value of the motor following the second test current command value as the amount of change in the current flowing through the motor.

9. The control device according to claim 1 or claim 2, wherein the temperature estimation unit estimates the temperature of the coil based on a temperature formula model that shows the relationship between the electrical resistance value of the motor and the temperature of the coil.

10. The control device according to claim 1 or 2, wherein the voltage command unit stops the drive control of the motor when the temperature of the coil estimated by the temperature estimation unit is equal to or greater than a third reference value.

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