JP5616088B2 - Inverter protection device, method and program - Google Patents

Description

  The present invention relates to an inverter protection device, method, and program.

  2. Description of the Related Art Conventionally, it is known that a plurality of power elements that constitute an inverter that is a power conversion device that converts direct current into desired alternating current protects a circuit from overheating due to loss. For example, in Patent Document 1, there is a technique for protecting the power element from overheating by estimating the temperature of the junction part from the case temperature covering the power element and limiting the output of the power element when the allowable value is exceeded. Proposed.

JP 2008-131722 A

  However, although the transient temperature rise of the junction portion contributes to the life of the power element, in the method of Patent Document 1, the estimated temperature of the junction portion exceeds the allowable operating temperature even once. In this case, it was determined that the power element was overheated abnormally, so that a transient temperature rise of the power element could not be detected, and the inverter capacity could not be fully utilized.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an inverter protection device, method, and program capable of making the most of the inverter's ability while preventing inverter failure. To do.

In order to solve the above problems, the present invention employs the following means.
The present invention protects overheating of a plurality of power elements constituting an inverter that converts direct current into desired alternating current, and switches between a device with a high drive priority and a device with a low drive priority that are not driven simultaneously. An inverter protection device applied to an industrial vehicle comprising a motor to be operated and the inverter provided corresponding to the motor, wherein the detection means detects the temperature of the power element, and is detected by the detection means A first determination for determining whether or not the measured temperature is equal to or higher than a predetermined temperature; and a second determination for determining whether or not the number of times the predetermined temperature is equal to or higher than the predetermined temperature as a result of the first determination. And the predetermined number of times compared in the second determination is set lower by a predetermined amount than the number of times of life that is the number of times that the life of the power element can be maintained, and the second determination As a result, a warning output means for outputting a warning signal for encouraging protection of the inverter when the number of times the temperature becomes equal to or higher than the predetermined temperature is greater than or equal to the predetermined number of times, and the output of the inverter is controlled based on the warning signal Control means, and the determination means is provided with a plurality of the predetermined number of times to be compared in the second determination, and the first predetermined number of times until the number of times of life is left, and the first A second predetermined number of times that is closer to the number of times of life than a predetermined number of times, and the control means exceeds the first predetermined number of times and drives the device having a low drive priority. reduces the output of the inverter, it exceeds the second predetermined number of times, in case of driving both the driving higher priority device and the driving low-priority device, inverter to reduce the output power of the inverter To provide a data protection device.

According to such a configuration, it is determined whether the temperature of the power element detected by the detection means is equal to or higher than a predetermined temperature (first determination), and the number of times when the temperature is equal to or higher than the predetermined temperature is equal to or higher than the predetermined number of times. It is determined (second determination) whether or not. Further, as a result of the second determination, based on a warning signal that prompts protection of the inverter that is output when a predetermined number of times that is lower than a predetermined number of times that is the number of times that the life of the power element can be maintained is exceeded. The output of the element is controlled. Thus, the temperature of the power element is detected, and the number of times the detected temperature is equal to or higher than the predetermined temperature is compared with a predetermined number of times set lower than the number of lifetimes that can maintain the life of the power element. It is possible to reliably detect that the lifetime is approaching in a state where the lifetime is maintained (before the failure). Further, by comparing the number of times that the power element becomes equal to or higher than the predetermined temperature with the predetermined number of times, it is possible to determine a transient temperature rise of the power element, and to perform control that makes the best use of the capacity of the inverter. Furthermore, since the output of the inverter is controlled based on the warning signal, it is possible to prevent a failure due to use exceeding the number of lifetimes.
In addition, for example, in the case of a motor that switches between a cargo handling device and a steering device to drive, when the first predetermined number of times is exceeded, the output of the cargo handling device is reduced and the output of the steering device is not changed. Further, when the second predetermined number of times is exceeded, the outputs of the cargo handling device and the steering device are changed. Thereby, the lifetime of an inverter can be extended, maintaining the bending performance required for an industrial vehicle as much as possible.

  At the timing when the warning signal is output by the warning output means of the inverter protection device, the count is estimated based on the count-up number that is the number of times the predetermined temperature or more per unit time based on the result of the second determination. Presenting means for presenting a first replacement time that is a power element replacement time and a second replacement time that is a power element replacement time estimated by limiting the output of the inverter by the control means. It is good to do.

  Since the first replacement time of the power element when the output of the inverter is not limited and the second replacement time of the power element when the output of the inverter is limited are presented, for example, the motion of the vehicle that changes depending on the output of the inverter The user can select whether to extend the life of the inverter even if the performance is lowered, or to maintain the motion performance without considering the life of the inverter.

  The inverter protection device is applied to an industrial vehicle including a plurality of different devices, a motor provided in each of the plurality of different devices, and the inverter provided corresponding to the motor. The control means of the inverter protection device may limit the output of another device when the output of at least one of the different devices is limited.

  For example, when the output of the traveling inverter is limited, the output of the steering inverter that does not use the inverter and the motor in common with the traveling one is also limited. Thereby, while extending the lifetime of the inverter of an industrial vehicle, the driving | operation which ensured safety can be performed.

The present invention protects overheating of a plurality of power elements constituting an inverter that converts direct current into desired alternating current, and switches between a device with a high drive priority and a device with a low drive priority that are not driven simultaneously. An inverter protection method applied to an industrial vehicle comprising a motor to be operated and the inverter provided corresponding to the motor, wherein the detection process detects the temperature of the power element, and is detected by the detection process A first determination for determining whether or not the measured temperature is equal to or higher than a predetermined temperature; and a second determination for determining whether or not the number of times the predetermined temperature is equal to or higher than the predetermined temperature as a result of the first determination. And the predetermined number of times compared in the second determination is set lower by a predetermined amount than the number of lifetimes that is the number of times that the life of the power element can be maintained, and the second determination As a result, a warning output process for outputting a warning signal for encouraging protection of the inverter when the number of times when the temperature is equal to or higher than the predetermined temperature is equal to or higher than the predetermined number of times, and the output of the inverter is controlled based on the warning signal In the determination process, a plurality of the predetermined number of times compared in the second determination are provided, and a first predetermined number of times until the number of lifetimes is left, and the first number of times A second predetermined number of times that is closer to the number of times of life than a predetermined number of times, and the control process exceeds the first predetermined number of times and drives the device having a low driving priority. reduces the output of the inverter, it exceeds the second predetermined number of times, in case of driving both the driving higher priority device and the driving low-priority device, inverter to reduce the output power of the inverter To provide a data protection method.

The present invention protects overheating of a plurality of power elements constituting an inverter that converts direct current into desired alternating current, and switches between a device with a high drive priority and a device with a low drive priority that are not driven simultaneously. And an inverter protection program applied to an industrial vehicle including the inverter provided corresponding to the motor, wherein the temperature detected by the detecting means for detecting the temperature of the power element is predetermined. A determination process for performing a first determination for determining whether or not the temperature is equal to or higher than a temperature, and a second determination for determining whether or not the number of times the predetermined temperature is equal to or higher than the predetermined temperature as a result of the first determination. And the predetermined number of times compared in the second determination is set a predetermined amount lower than the number of lifetimes that is the number of times that the lifetime of the power element can be maintained. A warning output process for outputting a warning signal for encouraging protection of the inverter when the number of times the predetermined temperature or higher is equal to or higher than the predetermined number of times, and a control process for controlling the output of the inverter based on the warning signal In the determination process, a plurality of the predetermined number of times compared in the second determination is provided, and a first predetermined number of times until the number of times of the life is left, and the first predetermined number of times And a second predetermined number of times that is closer to the number of times of life, and when the control process exceeds the first predetermined number of times and drives the device having a low driving priority, reduce the output, it exceeds the second predetermined number of times, in case of driving both the driving higher priority device and the driving low-priority device, competent to reducing the output of the inverter To provide an inverter protection program to be executed by the over data.

  The present invention has an effect of making the most of the capacity of an inverter while preventing failure of the inverter.

It is the figure which showed schematic structure of the motor control system which concerns on the 1st Embodiment of this invention. It is an operation | movement flow of the inverter protection apparatus which concerns on the 1st Embodiment of this invention. It is the figure which showed schematic structure of the motor control system which concerns on the 2nd Embodiment of this invention. It is the figure which showed the relationship between the operating time of a forklift and the count-up number. It is an operation | movement flow of the inverter protection apparatus which concerns on the 2nd Embodiment of this invention. It is an operation | movement flow of the inverter protection apparatus which concerns on the 3rd Embodiment of this invention. It is an operation | movement flow of the inverter protection apparatus which concerns on the 4th Embodiment of this invention.

Embodiments of an inverter protection device and method and a program according to the present invention will be described below with reference to the drawings. In the embodiment, a case where an industrial vehicle to which the inverter protection device is applied is a forklift will be described as an example.
[First Embodiment]
FIG. 1 is a diagram illustrating a schematic configuration of a motor control system 1 according to the present embodiment.
The motor control system 1 includes inverters 3 a, 3 b, 3 c, an inverter protection device 10, and an input / output device 4 corresponding to the motor to be driven.
In FIG. 1, inverters 3a, 3b, and 3c are provided corresponding to motors 2a, 2b, and 2c corresponding to devices to be driven, respectively. For example, as shown in FIG. 1, there is a traveling inverter 3a that drives the traveling motor 2a, a cargo handling inverter 3b that drives the cargo handling motor 2b, and a steering inverter 3c that drives the steering motor 2b.

The inverter protection device 10 includes temperature detection units (detection means) 11a, 11b, and 11c corresponding to the inverters 3a, 3b, and 3c, and a drive unit 12, respectively. Hereinafter, unless otherwise specified, the motor is described as the motor 2, the inverter as the inverter 3, and the temperature detection unit as the temperature detection unit 11.
The temperature detection unit 11 detects the temperatures of the plurality of power elements constituting the inverter 3 and outputs the detected temperature information to the drive unit 12. For example, the temperature detection unit 11 may be attached to a power element covering or the like, and may detect the case temperature, or may directly detect the temperature of the power element by being directly attached to an aluminum wire (junction) part. Well, the temperature detection method is not particularly limited.

The drive unit 12 includes a determination unit (determination unit) 13, a warning output unit (warning output unit) 14, and a control unit (control unit) 15.
The determination unit 13 determines whether or not the temperature detected by the detection unit 11 is equal to or higher than a predetermined temperature, and whether the number of times that the first determination results in a predetermined temperature or higher is equal to or higher than a predetermined number of times. A second determination is made to determine whether or not. Specifically, the determination unit 13 determines whether or not the temperature input from the detection unit 11 is equal to or higher than a predetermined temperature. If the temperature is equal to or higher than the predetermined temperature, the count-up number that counts the number of times the predetermined temperature is exceeded. Increase by one. Moreover, the determination part 13 determines whether the total number of count-up number is more than predetermined number. Further, the determination unit 13 outputs the determination result to the warning output unit 14.

  Here, the number of times defined as the predetermined number of times is a predetermined amount of margin (for example, the number of times that the power element is not hindered even when the temperature exceeds a predetermined temperature) provided by a manufacturer or the like (for example, It is assumed that the number of times (for example, 80% of the number of times of life) is taken into consideration.

  As a result of the second determination, the warning output unit 14 outputs a warning signal that prompts protection of the inverter 3 when the total number of count-ups (the number of times the predetermined temperature is exceeded) exceeds a predetermined number. For example, if the predetermined number of times is defined as 20% less than the number of lifespans, if the total number of count-ups is 80% or more of the number of lifespans as a result of the second determination, the warning output unit 14 A warning signal (alarm) is output to the input / output device 4 and a warning signal is output to the control unit 15.

The control unit 15 controls the output of the inverter 3. Specifically, the control unit 15 performs control to reduce the output of the power element of the inverter 3. For example, the control unit 15 has an output limit table that defines an output limit value according to the warning signal, reads the output limit value according to the warning signal based on the output limit table, and further outputs the output limit value. Is output to a drive circuit (not shown).
The drive circuit controls the inverter 3 by a drive signal generated based on the control signal.

  The input / output device 4 includes an input unit 41 such as a keyboard and a mouse, and an output unit 42 such as a display and a warning light. The input / output device 4 is communicably connected to the inverter protection device 10 and exchanges information with the inverter protection device 10. Specifically, when the warning signal output from the warning output unit 14 is acquired, the input / output device 4 notifies the operator of warning information (alarm information) based on the acquired warning signal via the output unit 42. The method of notifying the operator is, for example, turning on a warning lamp that notifies that the total number of count-ups exceeds a predetermined number, or displaying a warning message on the display.

Next, the operation of the inverter protection device 10 according to this embodiment will be described with reference to FIGS. 1 and 2.
When each temperature detection unit 11 detects the temperature of the power element of the inverter 3, temperature information is output to the drive unit 12. When temperature information is input to the determination unit 13 of the drive unit 12 (step SA1), a first determination is performed on the detected temperature (step SA2). If the temperature is equal to or higher than the predetermined temperature, the count-up number is incremented by 1 (step SA3), and then the second determination is performed on the count-up number (step SA4). As a result of the second determination, when it is determined that the total number of count-ups is equal to or greater than a predetermined number, a warning signal is output from the warning output unit 14 to the input / output device 4 to prompt the operator to protect the inverter 3. In addition, a warning signal is output to the control unit 15 (step SA5).

  When a warning signal is input to the input / output device 4, warning information corresponding to the warning signal is output to the output unit 42. Thereby, the operator can grasp | ascertain whether the protection of the inverter 3 is required by confirming the information provided from the output part 42. FIG. When a warning signal is input to the control unit 15, an output limit value corresponding to the warning signal is read from the output limit table, and a control signal determined based on the output limit value is output to the drive circuit. . The drive circuit controls the inverter 3 with the drive signal of the inverter 3 determined based on the input control signal (step SA6).

  As described above, since the warning signal is detected and the output of the power element of the inverter 3 is limited, the failure of the power element can be avoided. When notification of warning information by these input / output devices 4 and output restriction by the control unit 15 are performed, this processing is terminated. On the other hand, if it is determined in step SA2 that the temperature is not higher than the predetermined temperature, or step SA4 is not higher than the predetermined number of times, the process returns to step SA1 to repeat the present process.

In the above-described embodiment, the inverter protection device is premised on processing by hardware, but is not limited to such a configuration. For example, a configuration in which processing is performed separately by software is also possible. In this case, the inverter protection device includes a main storage device such as a CPU and a RAM, and a computer-readable recording medium on which a program for realizing all or part of the above processing is recorded. The CPU reads out the program (inverter protection program) recorded in the storage medium and executes information processing / arithmetic processing, thereby realizing processing similar to that of the above-described inverter protection device.
Here, the computer-readable recording medium means a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like. Alternatively, the computer program may be distributed to the computer via a communication line, and the computer that has received the distribution may execute the program.

  As described above, according to the inverter protection device 10 and the method and the program according to the present embodiment, it is determined whether or not the temperature of the power element detected by the detection unit 11 is equal to or higher than a predetermined temperature (first It is determined (second determination) whether or not the number of times that the temperature is equal to or higher than the predetermined temperature is equal to or higher than the predetermined number of times. Further, as a result of the second determination, based on a warning signal that prompts protection of the inverter that is output when a predetermined number of times that is lower than a predetermined number of times that is the number of times that the life of the power element can be maintained is exceeded. The output of the element is controlled.

  As described above, the number of times that the temperature of the power element is detected and the detected temperature is equal to or higher than the predetermined temperature (the total number of count-ups) is set to be lower than the number of times that the life of the power element can be maintained. Therefore, it is possible to reliably detect that the life is approaching in a state where the life of the power element is maintained (before failure). Further, by comparing the number of times that the power element becomes equal to or higher than the predetermined temperature with the predetermined number of times, it is possible to determine a transient temperature rise of the power element, and to perform control that makes the best use of the capacity of the inverter. Furthermore, since the output of the power element is controlled based on the warning signal, it is possible to prevent a failure due to use exceeding the number of lifetimes.

  In the present embodiment, the output process in the input / output device 4 and the control process of the inverter 3 by the control unit 15 are described as being performed based on the output warning signal. However, the present invention is not limited to this. . For example, at least one of output processing in the input / output device 4 and control processing of the inverter 3 by the control unit 15 may be executed.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIGS.
The present embodiment is different from the first embodiment in that the drive unit 12 is provided with a presentation unit (presentation unit) that presents to the operator whether or not to perform inverter output control when a warning signal is detected. It is. Hereinafter, regarding the inverter protection device 10 ′ of the present embodiment, description of points that are the same as those of the first embodiment will be omitted, and different points will be mainly described.

As shown in FIG. 3, the inverter protection device 10 ′ includes a presentation unit 16 and a time measuring unit 17 in addition to the configuration of the first embodiment.
When the total number of count-ups is equal to or greater than the predetermined number as a result of the second determination, the determination unit 13 outputs the number information to the presentation unit 16.
The timer unit 17 measures the operating time of the forklift and outputs the measured time information to the presentation unit 16.

  The presentation unit 16 includes a first replacement time that is a power device replacement time estimated based on the count-up number per unit time based on the result of the second determination at the time when the warning signal is output by the warning output unit 14. And the second replacement time, which is the power device replacement time estimated by limiting the output of the power device of the inverter 3 by the control unit 15, is presented.

For example, the presentation unit 16 calculates the number of count-ups per unit time based on the operation time of the forklift up to the timing when the warning signal is output and the total number of count-ups acquired from the determination unit 13. The replacement life time of the power element of the inverter 3 (hereinafter referred to as “first replacement time”) is estimated from the calculation result and presented.
FIG. 4 shows an example of a diagram in which the horizontal axis indicates the operating time of the forklift and the vertical axis indicates the count-up number. When the inverter 3 is driven as it is without limiting the output of the inverter 3 based on the graph shown in FIG. 4 (see the line (a) in FIG. 4), the first replacement of the power element is performed at time t1. It is estimated that the time will be reached, and the presentation unit 16 outputs the estimation result to the input / output device 4.

  In addition, the presentation unit 16 determines the degree to which the control unit 15 limits the output of the inverter 3 at the timing when the warning signal is output, and the replacement life time estimated according to the degree of the restriction (hereinafter “second replacement time”). ”). Here, the degree of restriction and the replacement life time corresponding to the degree are, for example, when the cargo handling performance of the cargo handling inverter 3 is limited (reduced) by 20%, the second exchange time is 2 at time t2 (for example, 2 times from time t1). Week extension) (see line (b) in FIG. 4), when the cargo handling performance of the cargo handling inverter 3 is limited (reduced) by 50%, the second replacement period is time t3 (for example, one month after time t1). (See line (c) in FIG. 4) and the like.

The control unit 15 outputs a control signal of a drive circuit that drives the inverter 3 based on the control mode information acquired from the input / output device 4. Here, the control mode is an operation control mode of the motor 2 defined according to the degree of limiting the output of the inverter 3 as described above.
The input / output device 4 outputs to the output unit 42 information on control modes respectively corresponding to the first exchange time and the second exchange time acquired from the presentation unit 16. When the control mode is selected by the operator from the control modes corresponding to the first replacement time and the second replacement time presented from the output unit 42 and input via the input unit 41, the input / output device 4 Information on the selected control mode is output to the inverter protection device 10.

  Next, the operation of the inverter protection device 10 ′ according to the present embodiment will be described with reference to FIGS. The same processing is independently performed in parallel for the traveling inverter 3a corresponding to the traveling motor 2a, the traveling inverter 3b corresponding to the traveling motor 2b, and the traveling inverter 3c corresponding to the traveling motor 2c. However, here, the description will be made by paying attention to the traveling motor 2a and the traveling inverter 3a.

  When the temperature of the power element of the inverter 3 is detected by the temperature detection unit 11, temperature information is output to the drive unit 12. When temperature information is input to the determination unit 13 of the drive unit 12 (step SB1), a first determination is performed on the detected temperature (step SB2). If the temperature is equal to or higher than the predetermined temperature, the count-up number is incremented by 1 (step SB3), and then the second determination is performed on the count-up number (step SB4).

  As a result of the second determination, when it is determined that the total number of count-ups is equal to or greater than a predetermined number, a warning signal is output from the warning output unit 14 to the input / output device 4 to prompt the operator to protect the inverter 3. In addition, the frequency information is output to the presentation unit 16. In addition, information on the operating time of the forklift measured by the timer unit 17 is output to the presentation unit 16. The presenting unit 16 estimates and presents the first life time and the second life time based on the acquired operating time information and frequency information (step SB5).

  The input / output device 4 displays information on the first lifetime and the second lifetime acquired from the presentation unit 16. Based on the information output to the output unit 42 of the input / output device 4, the operator selects a control mode of the cargo handling inverter 3b and inputs it from the input unit 41 (step SB6). The input unit 41 outputs information on the control mode selected by the operator to the inverter protection device 10. The control unit 15 controls the inverter 3b based on the control mode information acquired from the input / output device 4, limits the output of the inverter 3b according to the control mode selected by the operator (step SB7), and performs this process. finish. If it is determined in step SB2 that the temperature is not equal to or higher than the predetermined temperature, or step SB4 is not equal to or higher than the predetermined number of times, the process returns to step SB1 and this process is repeated.

  Thus, the first replacement time of the power element when the output of the inverter is not limited and the second replacement time of the power element when the output of the inverter is limited are presented and provided to the operator. Control such as extending the life of the inverter even when the vehicle's motion performance, which changes according to the output of the inverter, is reduced, or maintaining the motion performance without considering the life of the inverter, can be selected on the operator side.

  In the present embodiment, the information to be presented to the input / output device 4 by the presentation unit 16 has been described using the graph as illustrated in FIG. 4 as an example, but is not limited thereto. For example, the replacement life time may be indicated by a list such as a numerical value.

[Third Embodiment]
Next, a third embodiment of the present invention will be described with reference to FIG.
In the present embodiment, in the case of a forklift that switches a pair of inverters and motors to drive different devices, the first embodiment and the point that the device is controlled stepwise according to the determination result of the determination unit Different from the second embodiment. Hereinafter, regarding the inverter protection device of the present embodiment, description of points that are common to the first embodiment and the second embodiment will be omitted, and different points will be mainly described.

  Note that different devices in the present embodiment are a device having a high drive priority and a device having a low drive priority that are not driven simultaneously. Moreover, the inverter protection apparatus of this embodiment is an industrial vehicle (for example, a forklift) provided with a motor that switches between a cargo handling device and a steering device and an inverter provided corresponding to the motor as different devices. A case where the method is applied to will be described as an example.

  The determination unit is provided with a plurality of predetermined times to be compared in the second determination, the first predetermined number in which the number of times up to the life number is left, and the second number that is closer to the life number than the first predetermined number of times. A predetermined number of times. Here, the first predetermined number of times is a number of times to determine whether or not to reduce the inverter output when operating a device having a low driving priority (for example, a cargo handling device), and the second predetermined number of times is a driving priority. This is the number of times to determine whether or not to reduce the inverter output when operating a device having a high drive priority (for example, a steering device), in addition to reducing the inverter output when operating a low device.

  Further, the operation mode of the forklift (that is, the operation mode for reducing the output of the device with low driving priority) when the total number of count-ups is equal to or more than the first predetermined number and smaller than the second predetermined number by the determination unit. Forklift operation mode when mode 1 is equal to or greater than the first predetermined number of times and equal to or greater than the second predetermined number of times (that is, an operation that reduces the output of a device with a low drive priority and a device with a high drive priority) Mode) is mode 2.

  The control unit outputs a control signal to the drive circuit in order to reduce the output of the inverter when the count-up number is equal to or greater than the first predetermined number of times and an apparatus with a low drive priority (for example, a cargo handling apparatus) is driven. In addition, the control unit reduces the output of the inverter when the count-up number is equal to or greater than the second predetermined number of times and a device with a high drive priority (for example, a steering device) and a device with a low drive priority are driven.

Next, the operation of the inverter protection device according to the present embodiment will be described with reference to FIGS. 1 and 6.
When the temperature of the power element of the inverter 3 is detected by the temperature detection unit 11, temperature information is output to the drive unit 12. When temperature information is input to the determination unit 13 of the drive unit 12 (step SC1), a first determination is performed on the detected temperature (step SC2). If the temperature is equal to or higher than the predetermined temperature, the count-up number is increased by 1 (step SC3), and then it is determined whether or not the increased count-up number is the first predetermined number of times of the second determination (step SC4). ).

  When it is determined that the number of times is equal to or greater than the first predetermined number of times of the second determination, the operation mode of the forklift is set to mode 1, and the output of the inverter is reduced only when the cargo handling device is driven (step SC5). Further, it is determined whether or not the count-up number is the second predetermined number of the second determination (step SC6). If it is determined that the second predetermined number of times or more of the second determination is reached, the operation mode of the forklift is set to mode 2, and the output of the inverter is output when the cargo handling device is driven and when the steering device is driven. (Step SC7), and this process is terminated. If it is determined in step SC2 that the temperature is not higher than the predetermined temperature, step SC4 is not higher than the first predetermined number of times of the second determination, or step SC6 is not higher than the second predetermined number of times of the second determination, the process returns to step SC1. Repeat this process.

  As described above, by providing a plurality of second determination threshold values for determining whether or not to limit the output, it is possible to limit the output of the inverter step by step, and to avoid the failure of the power element. Thereby, the lifetime of an inverter can be extended, maintaining the bending performance (performance of a steering device) required for an industrial vehicle as much as possible.

  Further, for other devices other than different devices that drive by switching between a pair of inverters and motors, as described in the first embodiment, it is possible to perform prescribed processing according to the warning signal, As described in the second embodiment, the control method may be selected by the operator.

[Fourth Embodiment]
Next, a fourth embodiment of the present invention will be described with reference to FIG.
In this embodiment, when a plurality of different devices are driven, the first implementation is performed in that the common inverter and the motor are not used, and the output of the other device is limited in accordance with the output limitation of the one device. This is different from the embodiment, the second embodiment, and the third embodiment. Hereinafter, regarding the inverter protection device of the present embodiment, description of points that are common to the first embodiment, the second embodiment, and the third embodiment is omitted, and different points are mainly described.

In the present embodiment, a case where a plurality of different devices that do not use a common inverter and motor are a forklift traveling device and a steering device will be described as an example.
The control unit limits the output of another device when limiting the output of at least one of a plurality of different devices. Specifically, description will be made using the operation flow of the present embodiment shown in FIGS.

The operation flow for controlling the traveling device is shown on the left side of FIG. 7, and the operation flow for controlling the steering device is shown on the right side of the drawing.
Step SD1 to step SD6 and step SE1 to step SE6 are the same as step SB1 to step SB6 of the second embodiment, and thus description thereof is omitted.

  In step SD6, when the operation mode A selected by the operator is an operation mode in which the inverter output is limited to extend the life, the output of the steering device is limited according to the operation mode A, and the steering device Is output to the control unit of the traveling device (step SD7), and the process is terminated. In addition, when the control unit of the traveling device acquires the information of the operation mode B selected by the operator as the operation mode of the traveling inverter and the information of the operation mode A acquired from the control unit of the steering device, The output of the inverter of the traveling device is limited by the output limit value determined based on the information of the operation mode A that is the operation mode in which the output is limited (step SE7), and this process ends.

  In this way, when driving different devices that do not share the inverter and the motor, when the output of one device is reduced, the output of the other device is also reduced, thereby reducing the life of the inverter of the industrial vehicle. The operation can be extended while ensuring safety.

DESCRIPTION OF SYMBOLS 1 Motor control system 4 Input / output device 10,10 'Inverter protection apparatus 11a, 11b, 11c Temperature detection part 13 Determination part 14 Warning output part 15 Restriction part 16 Presentation part

Claims (5)

A motor that protects overheating of a plurality of power elements that constitute an inverter that converts direct current into desired alternating current, and switches between a high drive priority device and a low drive priority device that are not driven simultaneously; and An inverter protection device applied to an industrial vehicle including the inverter provided corresponding to the motor,
Detecting means for detecting the temperature of the power element;
A first determination for determining whether or not the temperature detected by the detection means is equal to or higher than a predetermined temperature, and whether or not the number of times the predetermined temperature is equal to or higher than the predetermined temperature as a result of the first determination is equal to or higher than a predetermined number. Determination means for performing a second determination to determine;
The predetermined number of times compared in the second determination is set to be lower by a predetermined amount than the number of lifetimes that is the number of times that the life of the power element can be maintained, and as a result of the second determination, the predetermined number of times is equal to or higher than the predetermined temperature. A warning output means for outputting a warning signal for encouraging protection of the inverter when the number of times is equal to or greater than the predetermined number;
Control means for controlling the output of the inverter based on the warning signal,
The determination means includes a plurality of the predetermined number of times to be compared in the second determination, a first predetermined number in which a large number of times until the life number is left, and a closer to the number of lifespan than the first predetermined number of times. It has a second predetermined number is the number of,
The control means includes
When the first predetermined number of times is exceeded and the device with the lower drive priority is driven, the output of the inverter is reduced,
An inverter protection device that reduces the output of the inverter when the second predetermined number of times is exceeded and both the device having a high drive priority and the device having a low drive priority are driven.   The replacement timing of the power element estimated by the count-up number that is the number of times the predetermined temperature or more per unit time is based on the result of the second determination at the timing when the warning signal is output by the warning output means The present invention further comprises a presenting means for presenting a first replacement time, and presenting a second replacement time that is a replacement time of the power element estimated by limiting the output of the inverter by the control means. The inverter protection device described.   The present invention is applied to an industrial vehicle that drives a plurality of different devices and includes a motor provided in each of the different devices and the inverter provided corresponding to the motor, and the control means is the different The inverter protection device according to claim 1 or 2, wherein, when the output of at least one device is restricted among the plurality of devices, the output of other devices is restricted. A motor that protects overheating of a plurality of power elements that constitute an inverter that converts direct current into desired alternating current, and switches between a high drive priority device and a low drive priority device that are not driven simultaneously; and An inverter protection method applied to an industrial vehicle including the inverter provided corresponding to the motor,
A detection process for detecting the temperature of the power element;
A first determination for determining whether or not the temperature detected by the detection process is equal to or higher than a predetermined temperature, and whether or not the number of times the predetermined temperature is equal to or higher than the predetermined temperature as a result of the first determination is equal to or higher than a predetermined number. A determination process of performing a second determination to determine;
The predetermined number of times compared in the second determination is set to be lower by a predetermined amount than the number of lifetimes that is the number of times that the life of the power element can be maintained, and as a result of the second determination, the predetermined number of times is equal to or higher than the predetermined temperature. A warning output process for outputting a warning signal for encouraging protection of the inverter when the number of times is equal to or greater than the predetermined number of times;
A control process for controlling the output of the inverter based on the warning signal;
In the determination process, a plurality of the predetermined number of times to be compared in the second determination are provided, and a first predetermined number in which a large number of times until the lifetime number is left is closer to the lifetime number than the first predetermined number of times. It has a second predetermined number is the number of,
The control process is
When the first predetermined number of times is exceeded and the device with the lower drive priority is driven, the output of the inverter is reduced,
An inverter protection method for reducing the output of the inverter when the second predetermined number of times is exceeded and both the device having a high drive priority and the device having a low drive priority are driven. A motor that protects overheating of a plurality of power elements that constitute an inverter that converts direct current into desired alternating current, and switches between a high drive priority device and a low drive priority device that are not driven simultaneously; and An inverter protection program applied to an industrial vehicle comprising the inverter provided corresponding to the motor,
A first determination for determining whether or not the temperature detected by the detecting means for detecting the temperature of the power element is equal to or higher than a predetermined temperature, and the number of times that the predetermined temperature is equal to or higher than the predetermined temperature as a result of the first determination A determination process for performing the second determination to determine whether or not
The predetermined number of times compared in the second determination is set to be lower by a predetermined amount than the number of lifetimes that is the number of times that the life of the power element can be maintained, and as a result of the second determination, the predetermined number of times is equal to or higher than the predetermined temperature. A warning output process for outputting a warning signal for encouraging protection of the inverter when the number of times is equal to or greater than the predetermined number;
A control process for controlling the output of the inverter based on the warning signal;
In the determination process, a plurality of the predetermined number of times to be compared in the second determination are provided, and a first predetermined number in which a large number of times until the lifetime number is left, and closer to the lifetime number than the first predetermined number of times It has a second predetermined number is the number of,
The control process is
When the first predetermined number of times is exceeded and the device with the lower drive priority is driven, the output of the inverter is reduced,
An inverter protection program for causing a computer to reduce the output of the inverter when both the device having a higher drive priority and the device having a lower drive priority are driven when the second predetermined number of times is exceeded .

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