Temperature monitoring device and temperature monitoring method

Abstract

To enable overheat protection of an entire system including a motor, a driver, and a power cable.SOLUTION: A temperature monitoring device comprises: a calculation unit that performs a heat load calculation for at least one of a motor and a driver, and a power cable on the basis of a driving current supplied to the motor through the power cable from the driver; and a detection unit that detects an overheat condition of any one of the motor, the driver and the power cable on the basis of the results of the heat load calculation for at least one of the motor and the driver and the heat load calculation for the power cable.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a temperature monitoring device and a temperature monitoring method. [Background technology]

[0002] 2. Description of the Related Art Conventionally, there is a technique for protecting a driver, which is connected to a motor via a power cable and supplies a drive current to the motor via the power cable, from overheating (for example, see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6493259 Summary of the Invention [Problem to be solved by the invention]

[0004] In the conventional technology, the protection of the power cable connecting the motor and the driver was not taken into consideration. Therefore, when the power cable selected by the user was thin or depending on the power cable installation conditions, it was difficult to protect the power cable from overheating. For this reason, it was difficult to use a power cable that had appropriate performance without exceeding the specifications.

[0005] An object of the present disclosure is to provide a temperature monitoring device capable of protecting the entire system, including the motor, driver, and power cable, from overheating. [Means for solving the problem]

[0006] In order to solve the above problems, the temperature monitoring device according to the present disclosure employs the following configuration: The temperature monitoring device includes a calculation unit that performs a heat load calculation for at least one of the motor and the driver, and the power cable, based on a drive current supplied from the driver to the motor through the power cable, and a detection unit that detects an overheated state of any of the motor, the driver, or the power cable, based on the result of the heat load calculation.

[0007] The invention according to the present disclosure also includes a temperature monitoring method, a program for temperature monitoring, and a recording medium having such a program recorded thereon, which have the same characteristics as the temperature monitoring device described above.

[0008] In order to solve the above problems, the temperature monitoring device disclosed herein is a temperature monitoring device that monitors the temperature of each of the power cables connecting a motor and a driver that controls the operation of the motor, and is characterized in that the temperature monitoring device for the power cables includes a current value acquisition unit that acquires the value of the current supplied to the motor, a heat generation amount estimation unit that estimates the heat generation amount of the power cable as a first heat generation amount using a first thermal model that shows the relationship between the current value and the heat generation amount of the power cable, and an abnormality determination unit that determines the presence or absence of a heat generation abnormality in the power cable by comparing the first heat generation amount estimated by the heat generation amount estimation unit with a predetermined first threshold value.

[0009] In the above configuration, the heat generation amount in the power cable is estimated as the first heat generation amount by the first thermal model based on the current value supplied to the motor. Then, the presence or absence of a heat generation abnormality in the power cable is determined based on the estimated first heat generation amount.

[0010] Here, since the current value supplied to the motor is a value required for controlling the motor, there is no need to provide a separate configuration for acquiring the current value. In other words, the amount of heat generated in the power cable can be estimated without providing a separate configuration for measuring the amount of heat generated by the driver, such as a temperature sensor. This makes it possible to detect abnormal heating.

[0011] Furthermore, since the driver can detect abnormal heat generation in the power cable, for example, in the case of a driver that can handle multiple types of motors, no matter what type of power cable is connected, the driver itself can detect abnormal heat generation in the power cable and prevent the occurrence of problems.

[0012] Furthermore, even if an abnormality in heat generation occurs, it is possible to take action such as stopping the operation of the motor by using the driver function.

[0013] The temperature monitoring device according to the present disclosure may further include an output section that outputs information on the occurrence of a heating abnormality when the abnormality determination section determines that a heating abnormality has occurred.

[0014] According to the above configuration, if a heat generation abnormality occurs, it is possible to output a message to that effect to the outside, thereby enabling, for example, an administrator of the motor control system to accurately recognize the occurrence of an abnormal situation.

[0015] In the temperature monitoring device according to the present disclosure, the current value acquiring unit may acquire the current value by measuring an actual value of a current flowing through a power cable when power is supplied from a driver to a motor. Effect of the Invention

[0016] According to the present disclosure, it is possible to protect the entire system, including the motor, the driver, and the power cable, from overheating. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a diagram showing a schematic configuration of a motor control system. [Diagram 2] FIG. 2 is a diagram showing a schematic configuration of a control system in which a motor is incorporated. [Diagram 3] FIG. 3 is a diagram showing a control structure formed by the driver. [Figure 4] FIG. 4 is a diagram showing an example of the configuration of a calculation model for a motor. [Diagram 5] FIG. 5A is a diagram showing an example of the configuration of a calculation model for a driver, and FIG. 5B is a diagram showing a calculation model for a power cable. [Figure 6] FIG. 6 is a flowchart showing an example of processing by the electronic thermal unit. [Figure 7] FIG. 7 is a flowchart illustrating an example of processing by the setting unit. [Figure 8] 8A and 8B are explanatory diagrams of thermal curves (overheating characteristic graphs). [Figure 9] FIG. 9 is an explanatory diagram of the second embodiment. [Figure 10] 10A and 10B are explanatory diagrams of the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] The temperature monitoring device according to the present disclosure includes a calculation unit that performs a heat load calculation for at least one of the motor and the driver, and the power cable based on the drive current supplied from the driver to the motor through the power cable, and a detection unit that detects an overheated state (a state where the motor, the driver, or the power cable are hotter than necessary) of any of the motor, the driver, and the power cable based on the result of the heat load calculation. This makes it possible to grasp the overheated state of at least one of the motor and the driver, and the power cable.

[0019] Conventionally, protection of the power cable connecting the motor and the driver has not been taken into consideration. Also, when the power cable selected by the user of the motor and the driver is a thin cable or when the cable is laid in multiple layers, there is a problem that the cable cannot be protected from overheating. Such a temperature monitoring device makes it possible to protect the power cable from overheating, and therefore makes it possible to protect the entire system including the motor, driver, and power cable from overheating.

[0020] The calculation unit in the temperature monitoring device may perform a first calculation for calculating the thermal load of the motor, a second calculation for calculating the thermal load of the driver, and a third calculation for calculating the thermal load of the power cable. However, the calculation unit may perform the first calculation for calculating the thermal load of the motor and the second calculation for calculating the thermal load of the driver. In this case, the temperature monitoring device may further include a setting unit, which may adopt a configuration in which, when information indicating that the thermal load calculation (detection of an overheated state) of the power cable is on is input, the setting unit changes the parameters for the thermal load calculation of the motor set in the first calculation to parameters for the thermal load calculation of the motor and the power cable, and changes the threshold value for determining the overheated state of the motor to be compared with the result of the first calculation to the threshold value for determining the overheated state of the motor and the power cable, or changes the parameters for the thermal load calculation of the driver set in the second calculation to parameters for the thermal load calculation of the driver and the power cable, and changes the threshold value for determining the overheated state of the driver to be compared with the result of the second calculation to the threshold value for determining the overheated state of the driver and the power cable. In this way, the circuit scale or load of the calculation unit can be reduced.

[0021] The temperature monitoring device may also adopt the following configuration. That is, the setting unit calculates a protection level of the power cable according to at least one of inputs of information indicating the type of the power cable and information indicating the installation conditions of the power cable. The setting unit sets, in the calculation unit, parameters for heat load calculation for the power cable corresponding to the protection level, and sets, in the detection unit, a judgment threshold value for judging an overheated state of the power cable to be compared with the result of the heat load calculation by the calculation unit, the judgment threshold value corresponding to the protection level. In this way, it is possible to perform heat load calculation and detect an overheated state according to the specification, state, and usage environment of the power cable.

[0022] The control unit of the temperature monitoring device may further include a control unit that outputs information indicating the overload characteristics of the power cable, which corresponds to at least one of the information indicating the type of the power cable and the information indicating the installation conditions of the power cable. In this way, the user can understand the overload characteristics of the power cable and control the drive current to avoid an overheating state.

[0023] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A temperature monitoring device according to an embodiment of the present invention will be described below with reference to the drawings. The configurations of the embodiments are merely examples, and the present invention is not limited to the configurations of the embodiments.

[0024] First Embodiment 1 is a schematic diagram of a control system including a driver 4 that also operates as a temperature monitoring device of this embodiment. The control system includes a network 1, a motor 2, a load device 3, a driver 4, a standard PLC (Programmable Logic Controller) 5, a power cable 8, and , and terminal 9.

[0025] The control system is a system for driving and controlling a load device 3 together with a motor 2. The motor 2 and the load device 3 are treated as a control target 6 controlled by the control system. Here, examples of the load device 3 include various types of mechanical devices (for example, an arm of an industrial robot or a conveying device). The motor 2 is incorporated in the load device 3 as an actuator that drives the load device 3. For example, the motor 2 is an AC servo motor having a stator wound with a winding and a rotor. The motor 2 may have a configuration in which the stator is wound with a winding and has a rotor, and the specific configuration is not limited to an AC servo motor.

[0026] In addition, an encoder (not shown) is attached to the motor 2. A parameter signal related to the operation of the motor 2 is fed back and transmitted to the driver 4. This parameter signal transmitted as feedback (hereinafter referred to as a feedback signal) includes, for example, position information on the rotational position (angle) of the rotating shaft of the motor 2, information on the rotational speed of the rotating shaft, etc.

[0027] The driver 4 receives an operation command signal related to the operation (motion) of the motor 2 from the standard PLC 5 via the network 1, and also receives a feedback signal output from an encoder connected to the motor 2. Based on the operation command signal from the standard PLC 5 and the feedback signal from the encoder, the driver 4 performs servo control related to the drive of the motor 2, i.e., calculates a command value related to the operation of the motor 2, and supplies three-phase drive currents of u, v, and w to the motor 2 via a power cable 8 so that the operation of the motor 2 follows the command value. The drive current supplied to the motor 2 utilizes AC power sent from an AC power source 7 to the driver 4.

[0028] In this embodiment, the driver 4 is of a type that receives three-phase AC, but may be of a type that receives single-phase AC. The servo control by the driver 4 is feedback control that utilizes a position controller 41, a speed controller 42, and a current controller 43 that the driver 4 has.

[0029] 1, the driver 4 includes a position controller 41, a speed controller 42, and a current controller 43, which perform the above servo control. The driver 4 also includes an electronic thermal unit 150 (see FIG. 2) to protect the motor 2, the driver 4, and the power cable 8 from damage due to overheating.

[0030] The electronic thermal section 150 estimates the temperature of the windings of the motor 2, the temperature of the driver 4, and the temperature of the power cable 8, and judges whether the motor 2 is in an overheated state based on the estimated temperatures.

[0031] 2, the servo control by the driver 4 and the protection control of the motor 2 by the electronic thermal unit 150 will be described. The control structure is formed by executing a predetermined control program in the driver 4 having a predetermined arithmetic unit, memory, etc.

[0032] The position controller 41 performs, for example, proportional control (P control). Specifically, a speed command is calculated by multiplying a position deviation, which is a deviation between a position command notified from the standard PLC 5 and a detected position, by a position proportional gain Kpp. The position controller 41 has a position proportional gain Kpp in advance as a control parameter. Next, the speed controller 42 performs, for example, proportional integral control (PI control). Specifically, an integral amount of a speed deviation, which is a deviation between a speed command calculated by the position controller 41 and a detected speed, is multiplied by a speed integral gain Kvi, and a sum of the calculation result and the speed deviation is multiplied by a speed proportional gain Kvp to calculate a torque command. The speed controller 42 has a speed integral gain Kvi and a speed proportional gain Kvp in advance as control parameters. The speed controller 42 may perform P control instead of PI control. In this case, the speed controller 42 has a speed proportional gain Kvp in advance as a control parameter. Next, the current controller 43 generates a command voltage for driving the amplifier 44 based on the torque command calculated by the speed controller 42. The amplifier 44 outputs a drive current for driving the motor 2 in accordance with the generated command voltage, thereby controlling the drive of the motor 2. The current controller 43 includes a filter (first-order low-pass filter) related to the torque command and one or more notch filters, and has cutoff frequencies related to the performance of these filters as control parameters.

[0033] The control structure of the driver 4 includes a speed controller 42, a current controller 43, and a control target 6. The control structure includes a velocity feedback system in which the velocity feedback system and the position controller 41 are used as forward elements, and further includes a position feedback system in which the velocity feedback system and the position controller 41 are used as forward elements. With this control structure, the driver 4 can servo-control the motor 2 to follow the position command supplied from the standard PLC 5.

[0034] When the motor 2 is servo-controlled in this manner, if an excessive load (for example, a load exceeding the rated load of the motor 2) is applied to the motor 2 for a relatively long period of time, an excessive current will flow through the windings of the motor 2 for a long period of time. This may cause the temperature of the windings to rise excessively, resulting in burnout. Furthermore, if a current above the rated value is supplied from the driver 4 to the motor 2 for a long period of time, the temperature of the driver 4 or the power cable 8 may rise excessively, resulting in burnout. In order to protect the motor 2, driver 4, and power cable 8 from such damage, such as burnout, the driver 4 has an electronic thermal unit 150.

[0035] Specifically, the electronic thermal unit 150 has a calculation model 100 (an example of a calculation unit) and an overload determination unit 110 (an example of a detection unit). As shown in Fig. 3, the calculation model 100 includes a calculation model 100a for the motor 2, a calculation model 100b for the driver 4, and a calculation model 100c for the power cable 8. The overload determination unit 110 includes an overload determination unit 110a for the motor 2 corresponding to the calculation model 100a, an overload determination unit 110b for the driver 4 corresponding to the calculation model 100b, and an overload determination unit 110c for the power cable 8 corresponding to the calculation model 100c.

[0036] FIG. 4 shows a schematic structure of the calculation model 100a of the motor 2. The calculation model 100a is a program that calculates the winding temperature of the motor 2 in the electronic thermal unit 150, and outputs the winding temperature of the motor 2 when a heat flow in the motor 2 is given as an input. The heat flow can be regarded as a so-called copper loss caused by the electrical resistance of the winding coil of the motor 2, and is proportional to the square of the current flowing through the winding coil. The calculation model 100a is a thermal model that shows the relationship between the current value supplied to the motor 2 and the heat generation amount of the motor 2. For example, the calculation model 100 detects the current supplied to the motor 2 by the command voltage of the power control unit 43, thereby acquiring the current value, and calculates the heat flow per unit time from the current value. The calculation model 100 operates as a current value acquisition unit that acquires the current value supplied to the motor 2.

[0037] 4, the calculation model 100a includes, as sub-models constituting the calculation model 100a itself, a winding temperature characteristic model 101 and a stator temperature characteristic model 102. The winding temperature characteristic model 101 is a model for calculating the temperature characteristics of the windings in the motor 2 when the thermal effect of the stator is virtually removed.

[0038] The stator temperature characteristic model 102 includes a reference model 102' and an iron loss coefficient Kr that uses as an argument the rotation speed (rpm) of the rotor of the motor 2. The reference model 102' is a model for calculating the temperature characteristics of the stator when the thermal influence of the windings is virtually removed in the motor 2. The value of the iron loss coefficient Kr can vary depending on the rotation speed of the rotor.

[0039] In the stator temperature characteristic model 102, the input heat flow is multiplied by (1+Kr) and input to the reference model 102' to calculate the output of the stator temperature characteristic model 102. By having such a stator temperature characteristic model 102 in the calculation model 100a, it is possible to reflect the iron loss caused by the rotation of the rotor in the temperature characteristics of the stator, and it is possible to more suitably realize the estimation of the winding temperature of the motor 2 for overload protection.

[0040] In this way, the calculation model 100a includes the winding temperature characteristic model 101 and the stator temperature characteristic model 102, and as shown in FIG. 4, the sum of the outputs of the respective models is calculated as the winding temperature of the motor 2. This allows the motor winding temperature to be calculated taking into account the correlation between the stator and the winding.

[0041] Here, the winding temperature characteristic model 101 will be described. The winding temperature characteristic model 101 is expressed by the following formula 1, including the thermal resistance Ra and thermal time constant Ta of the winding, which are parameters related to the temperature characteristics of the winding (winding-related parameters). The thermal resistance Ra is a value indicating the difficulty of heat transfer, and is a parameter indicating the amount of temperature rise per amount of heat generated per unit time. In this embodiment, the thermal resistance when the winding of the motor 2 is regarded as a thermally homogeneous object is adopted. The thermal time constant Ta is a parameter indicating the degree of responsiveness of the winding to temperature changes, and is defined as the time required for the winding to change by 63.2% of the temperature difference when transitioning from an initial thermal equilibrium state to another thermal equilibrium state. Winding temperature characteristic model = Ra / (Ta s+1) (Equation 1)

[0042] Next, the stator temperature characteristic model 102 will be described. The reference model 102' of the stator temperature characteristic model 102 includes the thermal resistance Rb and thermal time constant Tb related to the stator, which are parameters related to the temperature characteristics of the stator (stator-related parameters), and is expressed by the following formula 2. The definition of the thermal resistance Rb is the same as the definition of the thermal resistance Ra above, and in this embodiment, the thermal resistance when the stator of the motor is regarded as a thermally homogeneous object is adopted. The thermal time constant Tb is a parameter representing the degree of responsiveness of the stator to temperature changes, and is the same as the definition of the thermal time constant Ta above. Stator temperature characteristic model = Rb / (Tb s+1) (Equation 2)

[0043] In the calculation model 100a, the input (heat flow in the motor 2) is passed to the winding temperature characteristic model 101 and the stator temperature characteristic model 102. The outputs of the models are then added together to obtain the output of the calculation model, i.e., the estimated temperature of the motor windings. When the outputs of the models 101, 102 are added together, a value obtained by multiplying the output of each model 101, 102 by a predetermined gain may be added. By configuring the calculation model 100a in this manner, the winding temperature of the motor is estimated taking into account the correlation between the stator and the windings.

[0044] 5A shows a configuration example of a calculation model 100b for a driver. The calculation model 100b includes a driver temperature characteristic model 101b. The driver temperature characteristic model 101b is a model for calculating temperature characteristics at a predetermined position of the driver 4. The predetermined position may be any position that generates heat in response to the supply of current to the motor 2, and may be, for example, a position where a predetermined circuit such as an IGBT included in the driver 4 is mounted.

[0045] The driver temperature characteristic model 101b is expressed by the following formula 3, including thermal resistance Rc and thermal time constant Tc, which are parameters related to the temperature characteristics of a predetermined position (circuit, etc.). The definition of thermal resistance Rc is the same as the definition of thermal resistance Ra above, and in this embodiment, the thermal resistance when the entire driver 4 or a predetermined position is regarded as a thermally homogeneous object is adopted. The thermal time constant Tc is a parameter that indicates the degree of responsiveness to temperature changes of the entire driver 4 or a predetermined position, and is the same as the definition of the thermal time constant Ta above. Driver temperature characteristic model = Rc / (Tc s+1) (Equation 3)

[0046] Calculation model 100b is a thermal model that indicates the relationship between the value of the current supplied to motor 2 and the amount of heat generated by driver 4, and calculates the temperature of driver 4 (referred to as "driver temperature") using driver temperature characteristic model 101b with heat flow dependent on the current (detected current) detected as the output of amplifier 44 as an input. Note that for driver 4, temperature characteristic models for multiple locations (multiple specified positions) may be prepared, including driver temperature characteristic model 101b for the specified position described above, and the driver temperature may be calculated by adding up the calculation results of these temperature characteristic models. In other words, even if the driver temperature is calculated based on multiple positions of driver 4, good.

[0047] Fig. 5B shows an example of the configuration of a calculation model 100c for a power cable. The calculation model 100c includes a cable temperature characteristic model 101c. The cable temperature characteristic model 101c is a model for calculating the temperature characteristics of the conductors constituting the power cable 8. As shown in the example of Fig. 5B, one cable temperature characteristic model may be prepared, or temperature characteristic models corresponding to the conductors u, v, and w may be prepared. The cable temperature characteristic model 101c corresponds to a first thermal model showing the relationship between the value of the current (detected current) supplied to the motor 2 and the amount of heat generated by the power cable 8.

[0048] The cable temperature characteristic model 101c is expressed by the following formula 4, including the thermal resistance Rd and the thermal time constant Td, which are parameters related to the temperature characteristics of the power cable 8. The definition of the thermal resistance Rd is the same as the definition of the thermal resistance Ra above, and in this embodiment, the thermal resistance when the entire power cable 8 is regarded as a thermally homogeneous object is used. The thermal time constant Td is a parameter that represents the degree of responsiveness of the entire power cable 8 to temperature changes, and is the same as the definition of the thermal time constant Ta above. Cable temperature characteristic model = Rd / (Td s+1) (Equation 4)

[0049] The calculation model 100c uses the heat flow dependent on the current value output from the amplifier 44, detected by the calculation model 100, as an input, to calculate the temperature of the power cable 8 (referred to as cable temperature) using a cable temperature characteristic model 101c. Note that the current value may be obtained by measuring the current flowing through the power cable 8 through which the driver 4 supplies power to the motor 2.

[0050] As described above, each of the calculation models 100a, 100b, and 100c outputs the temperature, driver temperature, and cable temperature of the motor 2. The overload determination unit 110a of the overload determination unit 110 determines, based on the temperature of the motor 2 which is the output of the calculation model 100a, whether there is a possibility that the motor 2 will reach an overload state, in other words, whether there is a risk that the temperature of the windings of the motor 2 will increase excessively.

[0051] The overload determination unit 110b of the overload determination unit 110 determines whether the driver 4 is likely to be in an overload state, in other words, whether the driver 4 is likely to be overheated overall or locally, based on the driver temperature, which is the output of the calculation model 100b. The overload determination unit 110c of the overload determination unit 110 determines whether the power cable 8 is likely to be in an overload state, in other words, whether the power cable 8 is likely to be overheated overall or locally, based on the cable temperature, which is the output of the calculation model 100c.

[0052] When the overload determination units 110a, 110b, and 110c determine that any one of the motor 2, the driver 4, and the power cable 8 is in an overload state, the driver 4 can stop driving the motor 2, the driver 4, and the power cable 8 to protect the system including the motor 2, the driver 4, and the power cable 8. The calculation model 100 corresponds to a heat generation amount estimation unit, and the overload determination unit 110 corresponds to an abnormality determination unit and an output unit.

[0053] FIG. 6 is a flowchart showing an example of processing by the electronic thermal unit 150. In step S101, the calculation models 100a, 100b, and 100c of the electronic thermal unit 150 calculate the temperature of the motor 2, the driver temperature, and the cable temperature. That is, the calculation model 100a calculates the temperature of the motor 2 (estimated value) according to the heat flow as a heat load calculation for the motor 2. The calculation model 100b calculates the driver temperature (estimated value) according to the heat flow as a heat load calculation for the driver 4. The calculation model 100c calculates the cable temperature (estimated value) according to the heat flow as a heat load calculation for the power cable 8. The order of calculation of each temperature is arbitrary, and they are executed in parallel. This may also be the case.

[0054] In step S102, the overload determination unit 110 determines whether any of the temperature of the motor 2, the driver temperature, and the cable temperature exceeds a threshold value. That is, the overload determination unit 110a determines whether the temperature of the motor 2 exceeds a threshold value for the motor 2, the overload determination unit 110b determines whether the driver temperature exceeds a threshold value for the driver 4, and the overload determination unit 110c determines whether the cable temperature exceeds a threshold value for the power cable 8. The order of these determinations is arbitrary, and these determinations may be performed in parallel. When it is determined that any of the threshold values ​​is exceeded, the remaining determinations may be canceled or stopped. If it is determined that any of the temperature of the motor 2, the driver temperature, and the cable temperature exceeds a threshold value, the process proceeds to step S103, and if not, the process proceeds to step S101.

[0055] In step S103, the electronic thermal unit 150 detects an abnormal temperature rise in the motor 2, the driver 4, or the power cable 8, and outputs information indicating an overheated state (abnormality or warning) of the motor 2, the driver 4, or the power cable 8. The information is output by, for example, illuminating or blinking an LED, outputting an alarm sound, or displaying information on a display. The configuration for outputting the information may be provided in the driver 4, or the information may be notified (displayed, etc.) using a display or speaker provided in the terminal 9. The electronic thermal unit 150 may also have a configuration for automatically stopping the operation of the driver 4 in addition to outputting the information indicating an abnormality or warning. However, the operation of the driver 4 may be stopped manually by a user who receives the information.

[0056] The terminal 9 is used by the user to make various settings for the electronic thermal unit 150 through the setting unit 120 provided in the driver 4. The terminal 9 is also used to notify the user of various information by displaying the information indicating the above-mentioned abnormalities and warnings, etc. The setting unit 120, like the electronic thermal unit 150, may be realized by program execution by a processor (CPU) provided in the driver 4, or may be realized by a dedicated circuit (hardware) implemented in the driver 4.

[0057] The terminal 9 has a processor, a memory, an input device, a display, a communication interface, etc. By executing a program stored in the memory, the processor reads and writes information from and to the memory, accepts information input by a user using the input device, displays the information on the display, and transmits and receives information to and from the setting unit 120 by controlling the communication interface.

[0058] For example, the user can turn on and off the heat load calculations for the motor 2, the driver 4, and the power cable 8. That is, the user can input information indicating the on or off status of each of the calculation models 100a, 100b, and 100c from the input device to the terminal 9.

[0059] The information indicating on or off is sent to the setting unit 120 via the network 1. The setting unit 120 turns on or off the corresponding calculation models 100a, 100b, and 100c based on the information indicating on or off. This makes it possible to turn on or off (set enable / disable) the thermal load calculation of the power cable 8. Turning off the thermal load calculation can reduce the calculation load on the processor (CPU). Note that it may or may not be possible to set the thermal load calculation for each of the motor 2 and the driver 4 to enable / disable (turn on / off the calculation models 100a, 100b).

[0060] In addition, the user can set the protection level of the power cable 8 by inputting the type of the power cable and the laying conditions of the power cable into the terminal 9. For example, when some of the following requirements are input, the processor of the terminal 9 or the setting unit 120 of the driver 4 sets the protection level of the power cable 8 based on the input information. The protection level of the power cable 8 corresponding to the information is calculated. Cable jacket material, thermal resistance of jacket material, or maximum operating temperature of cable - Cable wire outer diameter and length · Cable wire conductor material or electrical resistivity (resistivity, specific resistance) [Ω·m] Cable conductor diameter (AWG, sq.) or cross-sectional area Ambient temperature when laying the cable In case of multiple installation, multiple installation conditions If wiring is done through a wiring duct, the material of the wiring duct or the maximum operating temperature of the wiring duct material

[0061] For example, the terminal 9 is configured to display the above menu on a display and allow the user to select an option or input a value. Maximum cable operating temperature (options: 80℃, 85℃, 105℃) Cable conductor diameter (enter value: AWG / SQ) Ambient temperature when laying the cable (options: 0℃ 25℃ 40℃ 55℃ 70℃ 85℃) Multiple laying (Yes, No) Maximum operating temperature of wiring duct material when multiple wiring is used (options: 65℃, 80℃, 85℃, 105℃)

[0062] The memory of the driver 4 (or the terminal 9) stores one or more sets of parameters (such as thermal resistance Rd and time constant Td) to be set in the calculation model 100c of the power cable 8 corresponding to the protection level, and the setting unit 120 sets the parameters corresponding to the protection level acquired by its own calculation or acquired from the terminal 9 in the calculation model 100c. For example, the value of the thermal resistance Rd is set to be smaller as the conductor diameter of the cable wire becomes thicker. Also, for example, the value of the time constant Td is set to be smaller as the number of threads increases. Also, the parameters may be set so that the estimated value of the temperature output by the calculation model 100c is inflated as the ambient temperature increases. Instead of setting the parameters for the cable temperature calculation according to the ambient temperature, the threshold for detecting the overheating state may be lowered. The set of parameters may be calculated using an algorithm for parameter calculation based on input information. Also, the setting unit 120 acquires a threshold corresponding to the protection level stored in advance in the memory and sets it in the overload determination unit 110c. This makes it possible to calculate the thermal load according to the reduction rate of the allowable current for the power cables 8 that are laid in multiple locations, and thus makes it possible to protect the power cables 8 in an appropriate manner.

[0063] Furthermore, when the power cable 8 is laid in multiple rows, the user can input information indicating the laying conditions of the power cable 8 (laying (rows and stages), arrangement, center distance) to the setting unit 120 via the terminal 9. In this case, the setting unit 120 calculates the allowable current corresponding to the laying conditions and the parameters for the calculation model 100c corresponding to the allowable current, for example, using a correspondence table stored in a memory. Also, it calculates a threshold value corresponding to the allowable current. The setting unit 120 sets the calculated parameters to the calculation model 100c, and sets the calculated threshold value to the overload determination unit 110c. This makes it possible to perform thermal load calculation and overload determination according to the reduction rate of the allowable current for the power cable 8 laid in multiple rows, and it is possible to protect the power cable 8 in an appropriate manner.

[0064] 7 is a flowchart showing an example of processing by the setting unit 120. In step S201, the setting unit 120 acquires information indicating the type and installation conditions of the power cable 8 from the terminal 9. In step S202, the setting unit 120 calculates parameters and thresholds for thermal load calculation corresponding to the information acquired in step S201. In step S203, the setting unit 120 sets the parameters calculated in step S202 in the calculation model 100c, and sets the thresholds in the overload determination unit 110c.

[0065] Furthermore, the setting unit 120 may automatically change the parameters (such as the thermal time constant Td) and thresholds of the thermal load calculation according to the operation time (power supply time) of the motor 2 or the ambient temperature of the motor 2. The driver 4 measures the operation time (power supply time) of the motor 2, and the measured value can be used to change the parameters and thresholds. Furthermore, the ambient temperature may be predicted from the temperature of the motor 2, or the value of a temperature sensor that measures the outside air temperature may be used as the ambient temperature.

[0066] As an example of parameter change, when the operating time exceeds a predetermined time, the setting unit 120 makes the value of the thermal time constant smaller than the reference value. Also, when the ambient temperature is higher than the reference temperature or the range of the reference temperature, the setting unit 120 lowers the threshold value. Conversely, when the ambient temperature is lower than the range of the reference temperature, the setting unit 120 raises the threshold value. In this way, the motor 2 can be used appropriately while protecting the power cable 8 according to the usage conditions of the motor 2.

[0067] Furthermore, the setting unit 120 operates as a "control unit" and can generate and output information showing a thermal curve (overload characteristic graph) for the power cable 8 by using parameters and thresholds for thermal load calculation for the power cable 8 that depend on the type and installation conditions of the power cable 8. The overload characteristic graph is a graph showing the change in the time (detection time) until an overheating state is detected when a current greater than the rated current flows. The overload characteristic is usually represented by a graph with the horizontal axis representing current greater than the rated current and the vertical axis representing the time (detection time) until an overload (overheating state) is detected.

[0068] FIG. 8A shows a graph C indicating the overload characteristics of the power cable 8. In the overload characteristics graph, the detection time becomes shorter as the current increases. The numerical values ​​on which the graph C is based may be generated in the driver 4 or in the terminal 9. The processor of the terminal 9 displays the graph C on the display of the terminal 9. This allows the user to understand the overload characteristics according to the type of the power cable 8 and the installation conditions. As shown in FIG. 8B, in addition to the graph C, a graph M indicating the overload characteristics of the motor 2 and a graph D indicating the overload characteristics of the driver 4 may be displayed. As with the graph C, the numerical values ​​on which the graphs M and D are based may be generated by the driver 4 or in the terminal 9.

[0069] According to the first embodiment, the calculation models 100a, 100b, and 100c perform the thermal load calculation of the motor 2 and the thermal load calculation of the driver 4 (either one is acceptable), and the thermal load calculation of the power cable 8. Then, the overload determination units 110a, 110b, and 110c detect the overheat state of any of the motor 2, the driver 4, and the power cable 8. This allows the user to grasp these overheat states. In addition, the operation of the driver 4 is stopped in response to the detection of the overheat state, thereby protecting these. In addition, it is possible to appropriately control the drive current so that overheating does not occur. Furthermore, it is possible to avoid waste (disadvantages) when using an over-specified power cable. According to the first embodiment, it is possible to protect the entire system including the motor, the driver, and the power cable from overheating.

[0070] <Second embodiment> Next, a second embodiment will be described. Since the second embodiment has a similar configuration to the first embodiment, differences will be mainly described. Fig. 9 shows an example of the configuration of an electronic thermal unit 150A provided in a driver 4 in a motor control system according to the second embodiment. In the electronic thermal unit 150A, the calculation model 100c related to the power cable 8 and the overload determination unit 110c are omitted, and a calculation model 100a that performs a thermal load calculation (first calculation) of the motor 2 and a calculation model 100b that performs a thermal load calculation (second calculation) of the driver 4 are prepared.

[0071] In the second embodiment, the heat load calculations set in the calculation models 100a and 100b are As the initial values ​​of the parameters, the same parameters as those in the first embodiment, that is, the parameters for calculating the estimated value of the temperature of the motor 2 and the parameters for calculating the driver temperature (the estimated value of the temperature of the driver 4) are set. Furthermore, the same threshold values ​​as those in the first embodiment are set as initial values ​​in each of the overload determination units 110a and 110b. As a result, as shown in FIG. 10A, the graph M showing the overload characteristics of the motor 2 and the graph D showing the overload characteristics of the driver 4 become similar to the graphs M and D (FIG. 8B) in the first embodiment, respectively.

[0072] Here, it is assumed that the power cable 8 in the second embodiment has the same overload characteristics as the first embodiment, as shown in Fig. 10A. In this case, if the overload characteristics are as shown in graph 20 indicated by the dashed line in Fig. 10A, the overheating state is properly detected (an abnormality / warning is output) for all of the motor 2, the driver 4, and the power cable 8. However, in graphs M and D, the overheating state is not detected in the area 30 (shaded portion) shown in Fig. 10A, even though the power cable 8 is in an overheating state, and a warning or the like is not output.

[0073] For this reason, when the setting unit 120 (FIG. 2) in the second embodiment receives information indicating that the detection of the overheat state of the power cable 8 is on (enabled) from the terminal 9, the setting unit 120 changes the parameters (initial values) set in the calculation model 100a and the thresholds (initial values) of the overload determination unit 110a to parameters and thresholds that can detect the appropriate overheat state of the motor 2 and the power cable 8. For example, as shown in FIG. 10B, as parameters and thresholds of the thermal load calculation of the motor 2 and the power cable 8, parameters and thresholds for changing the graph M based on the initial values ​​to a graph M1 in which an overheat state is detected also in the region 30 are set in the calculation model 100a and the overload determination unit 110a (the parameters and thresholds are changed). When the parameters and thresholds of the calculation model 100a and the overload determination unit 110a are changed, the calculation model 100b and the overheat determination unit 110b are maintained in the on state. That is, the overheat state is detected according to the overload characteristics of the graph D shown in FIG. 10B. Therefore, the motor 2, the driver 4, and the power cable 8 are protected by the overload characteristics of graphs M1 and D.

[0074] Instead of changing the parameters and thresholds of the calculation model 100a and the overload determination unit 110a, the parameters and thresholds (initial values) of the calculation model 100b and the overload determination unit 110b may be changed to parameters and thresholds that can detect an appropriate overheating state for the driver 4 and the power cable 8. As the changed parameters and thresholds, parameters and thresholds that make the graph D shown in FIG. 10B a graph D1 that can detect an overheating state even in the region 30 can be applied. When the graph D1 is adopted, the graph M related to the motor 2 and the graph C related to the power cable 8 are included in the detection region of the overheating state based on the graph D1. For this reason, a configuration may be adopted in which the processing of the calculation model 100a and the overload determination unit 110a is turned off in accordance with the change in the parameters and thresholds of the calculation model 100b and the overload determination unit 110b according to the graph D1.

[0075] In response to receiving information indicating that the detection of an overheating state of the power cable 8 is ON, the parameters and thresholds of the calculation models 100a and 100b and the overload determination units 110a and 110b may be changed as described above. When the setting unit 120 receives information indicating that the detection of an overheating state of the power cable 8 is OFF (disabled) from the terminal 9, the setting unit 120 returns the changed parameters and thresholds to their original initial values.

[0076] According to the second embodiment, by omitting the calculation model 100c and the overload determination unit 110c, the load on the processor (CPU) of the driver 4 or the circuit scale can be reduced, while the overheated state of the power cable 8 can be properly detected, and overheat protection of the entire system including the motor, the driver, and the power cable can be achieved. The configuration of the embodiments of the present invention can be modified as appropriate within the scope of the object of the present invention.

[0077] <Additional Notes> a calculation unit (100) that performs a thermal load calculation (100a) of at least one of the motor (2) and the driver (4) and a thermal load calculation (100b) of the power cable (8) based on a drive current supplied from the driver (4) to the motor (2) through a power cable (8); a detection unit (110) that detects an overheated state of any of the motor (2), the driver (4) and the power cable (8) based on a result of a thermal load calculation of at least one of the motor (2) and the driver (4) and a thermal load calculation of the power cable; A temperature monitoring device (4). [Explanation of symbols]

[0078] 1. Network 2. Motor 3...Load device 4. Driver 5...Standard PLC 6. Control Object 7...AC power supply 8. Power cable 9. Terminal 41 Position controller 42 Speed ​​controller 43 Current controller 44 Amplifier 100···Calculation model 110...Overload judgment section 120 Setting section 150···Electronic thermal section

Claims

1. a calculation unit that performs a thermal load calculation for at least one of the motor and the driver, and the power cable, based on a drive current supplied from the driver to the motor through a power cable; a detection unit that detects an overheated state of any of the motor, the driver, and the power cable based on a result of the thermal load calculation; a setting unit that sets a thermal load calculation for the power cable to be enabled or disabled based on an input of information indicating whether the detection of an overheated state of the power cable is on or off; A temperature monitoring device comprising:

2. The setting unit sets a thermal load calculation for at least one of the motor and the driver to be enabled or disabled based on an input of information indicating whether an overheating state of at least one of the motor and the driver is on or off.

2. The temperature monitoring device of claim 1.

3. the calculation unit performs a first calculation to calculate a thermal load of the motor and a second calculation to calculate a thermal load of the driver, The setting unit, when receiving information indicating that the detection of the overheat state of the power cable is on, performs at least one of changing a parameter for the thermal load calculation of the motor being set in the first calculation to a parameter for the thermal load calculation of the motor and the power cable, and changing a threshold value for determining an overheat state of the motor, which is to be compared with a result of the first calculation, to a threshold value for determining an overheat state of the motor and the power cable; and changing a parameter for the thermal load calculation of the driver being set in the second calculation to a parameter for the thermal load calculation of the driver and the power cable, and changing a threshold value for determining an overheat state of the driver, which is to be compared with a result of the second calculation, to a threshold value for determining an overheat state of the driver and the power cable.

3. A temperature monitoring device according to claim 1 or 2.

4. The setting unit, when information indicating that the detection of the overheating state of the power cable is turned off is input, pre-sets parameters for the thermal load calculation of the motor and the power cable being set in the first calculation. and returning the parameters for the thermal load calculation of the motor and a threshold for determining an overheated state of the motor and the power cable, which is to be compared with the result of the first calculation, to a threshold for determining an overheated state of the motor; and returning the parameters for the thermal load calculation of the driver and the power cable, which are set in the second calculation, to parameters for the thermal load calculation of the driver, and returning the threshold for determining an overheated state of the driver and the power cable, which is to be compared with the result of the second calculation, to a threshold for determining an overheated state of the driver.

4. The temperature monitoring device of claim 3.

5. The setting unit acquires information indicating a protection level of the power cable according to at least one of input of information indicating the type of the power cable and information indicating the installation conditions of the power cable, sets a parameter for thermal load calculation for the power cable corresponding to the protection level in the calculation unit, and sets a determination threshold value for determining an overheating state of the power cable to be compared with a result of the thermal load calculation of the calculation unit, the determination threshold value corresponding to the protection level, in the detection unit. A temperature monitoring device according to any one of claims 1 to 4.

6. The power cable may further include a control unit that outputs information indicating an overload characteristic of the power cable, the information corresponding to at least one of information indicating a type of the power cable and information indicating an installation condition of the power cable. A temperature monitoring device according to any one of claims 1 to 5.

7. performing a thermal load calculation for at least one of the motor and the driver and a thermal load calculation for the power cable based on a drive current supplied from a driver to the motor through a power cable; Detecting an overheated state of any of the motor, the driver, and the power cable based on a result of a thermal load calculation of at least one of the motor and the driver, and a thermal load calculation of the power cable; setting a thermal load calculation for the power cable to be enabled or disabled based on an input of information indicating whether the detection of an overheated state of the power cable is on or off; The temperature monitoring method is executed by an information processing device.

8. The information processing device sets a thermal load calculation for at least one of the motor and the driver to be enabled or disabled based on an input of information indicating whether an overheating state of at least one of the motor and the driver is detected to be on or off. The temperature monitoring method of claim 7.

9. the information processing device performs a first calculation to calculate a heat load of the motor and a second calculation to calculate a heat load of the driver; When information indicating that the detection of the overheat state of the power cable is on is input, at least one of the following is performed: changing the parameters for the thermal load calculation of the motor being set in the first calculation to parameters for the thermal load calculation of the motor and the power cable, and changing the threshold value for determining the overheat state of the motor, which is compared with the result of the first calculation, to a threshold value for determining the overheat state of the motor and the power cable; changing the parameters for the thermal load calculation of the driver being set in the second calculation to parameters for the thermal load calculation of the driver and the power cable, and changing the threshold value for determining the overheat state of the driver, which is compared with the result of the second calculation, to a threshold value for determining the overheat state of the driver and the power cable.

9. The temperature monitoring method according to claim 7 or 8.

10. The information processing device, when information indicating that the detection of the overheating state of the power cable is turned off is input, sets parameters for thermal load calculation of the motor and the power cable being set in the first calculation. and returning the parameters for the thermal load calculation of the driver and the power cable set in the second calculation to parameters for the thermal load calculation of the motor, and returning the threshold for determining an overheated state of the motor and the power cable, which is to be compared with the result of the first calculation, to the threshold for determining an overheated state of the motor; and returning the parameters for the thermal load calculation of the driver and the power cable set in the second calculation to parameters for the thermal load calculation of the driver, and returning the threshold for determining an overheated state of the driver and the power cable, which is to be compared with the result of the second calculation, to the threshold for determining an overheated state of the driver.

10. The method of claim 9.

11. A temperature monitoring device for monitoring the temperature of a power cable connecting a motor and a driver that controls the operation of the motor, a current value acquisition unit that acquires a value of a current supplied to the motor; a heat generation amount estimation unit that estimates a heat generation amount of the power cable as a first heat generation amount using a first thermal model that indicates a relationship between the current value and a heat generation amount of the power cable; an abnormality determination unit that determines whether or not there is a heat generation abnormality in the power cable by comparing a first heat generation amount estimated by the heat generation amount estimation unit with a predetermined first threshold value; a setting unit that sets whether the first thermal model is enabled or disabled based on an input of information indicating whether detection of an overheated state of the power cable is on or off; A temperature monitoring device comprising:

12. The device further includes an output unit that outputs information on the occurrence of a heat generation abnormality when the abnormality determination unit determines that a heat generation abnormality has occurred.

12. The temperature monitoring device of claim 11.

13. The current value acquisition unit acquires the current value by measuring an actual value of a current flowing through the power cable when power is supplied from the driver to the motor.

13. A temperature monitoring device according to claim 11 or 12.

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