JP2018152929A - Motor drive device for detecting inverse converter of large leakage current - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a motor drive device detecting a set of an inverse converter generating the largest leakage current and a motor, easily and accurately.SOLUTION: A motor drive device 1 includes a forward converter 11 for converting AC power from AC power supply 3 into DC power, multiple inverse converters 12-n for converting DC power from the forward converter 11 into AC power for driving a motor, a diagnostic command section 13 for commanding so that power conversion of one of the multiple inverse converters 12-n is executed, a noise absorption circuit 14 for absorbing noise between the AC power supply 3 and the forward converter 11, a temperature measurement section 15 for measuring a temperature of a resistor 31 in the noise absorption circuit 14, a storage section 16 for storing the temperature measured by the temperature measurement section 15 in association with the inverse converters 12-n that has been commanded to execute power conversion at measurement time, and a leakage current determination section 17 which determines the inverse converter 12-n, when the highest temperature stored in the storage section 16 is measured, as the inverse converter generated with the maximum leakage current.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a motor drive device that detects an inverter having a large leakage current.

  In machine tools, forging machines, injection molding machines, industrial machines, or motor drive devices that drive motors in various robots, AC power supplied from an AC power source is once converted into DC power by a forward converter, and then further The AC power is converted to AC power by an inverse converter, and this AC power is used as driving power for a motor provided for each drive shaft. Inverse converters are provided in the same number as the number of motors in order to control driving of the motors by individually supplying driving power to the motors provided corresponding to the plurality of driving shafts. On the other hand, one forward converter is often provided for a plurality of inverse converters for the purpose of cost reduction and space reduction.

  In such a motor drive device, when PWM switching control is performed on the inverse converter, a leakage current is generated due to stray capacitance existing in the motor and the motor power cable. Since the leakage current causes malfunction or damage of the motor drive device or its peripheral devices, countermeasures are important.

  For example, the relationship between the inverter element temperature and the leakage current is examined by experiment and stored as a leakage current setting map, and when the inverter element temperature is given, a technique for estimating the magnitude of the corresponding leakage current from the map is derived. Is known (for example, see Patent Document 1).

  For example, a control device for controlling an air conditioner outdoor unit, a converter that converts the output of an alternating current power source into direct current, a current detection means that detects a current flowing through an electrolytic capacitor connected as a smoothing circuit in the converter, And a microcomputer that reads the leakage current of the electrolytic capacitor from the current detected by the current detection means, and the microcomputer uses a leakage current data to predict a failure or life of the electrolytic capacitor (for example, , See Patent Document 2).

JP 2011-172373 A JP 2007-318872 A

  In order to take measures against leakage current, it is necessary to measure the leakage current. Since the leakage current is generated by performing high-speed PWM switching control on the inverse converter that supplies driving power to the motor in the presence of the stray capacitance, the leakage current has a very high frequency. Therefore, it is difficult to directly measure the leakage current itself. When a motor is driven using an inverse converter, a leakage current increases or decreases. In a motor drive device that supplies drive power to a plurality of motors with a plurality of inverse converters, it is effective for the motor drive device to grasp the combination of the inverter and the motor that generate the largest leakage current. Therefore, a technique that can easily and accurately detect a combination of an inverter and a motor that generate the largest leakage current is desired.

  According to one aspect of the present disclosure, a motor drive device includes a forward converter that converts alternating current power supplied from an alternating current power source into direct current power and outputs the forward power, and a forward converter that is provided for each motor, and that is forward converted according to a received command. Power conversion operation for converting the DC power output from the converter into AC power for driving the motor, and power conversion only for one of the plurality of inverse converters and the plurality of inverse converters Noise absorption that absorbs the noise generated between the AC power supply and the forward converter, having a diagnostic command section that sequentially performs the process to command the operation for each inverse converter, a resistor and a capacitor Circuit, temperature measuring unit for measuring the temperature of the resistance, and inverse conversion that has been commanded so that the power conversion operation is performed by the diagnostic command unit when the temperature is measured by the temperature measuring unit The memory to be stored in association with the vessel And the reverse converter that has been commanded to perform the power conversion operation by the diagnostic command unit when the highest temperature among the temperatures stored in the storage unit is measured. And a leakage current determination unit for determining as a converter.

  According to the present invention, in a motor drive device that supplies drive power to a plurality of motors with a plurality of inverters, a pair of the inverter and the motor that generate the largest leakage current is detected easily and accurately. be able to.

It is a figure which shows the motor drive device by one Embodiment. It is a figure which shows the 1st form of the noise absorption circuit in the motor drive device by one Embodiment. It is a block diagram which shows the case where an alerting | reporting part is connected to the leakage current determination part. It is a flowchart which shows the operation | movement flow of the motor drive device by one Embodiment. It is a figure which shows the 2nd form of the noise absorption circuit in the motor drive device by one Embodiment. It is a figure which shows the 3rd form of the noise absorption circuit in the motor drive device by one Embodiment. It is a figure which shows the 4th form of the noise absorption circuit in the motor drive device by one Embodiment. It is a figure which shows the other form of the forward converter in the motor drive device by one Embodiment. It is a figure which shows the other form of the inverter in the motor drive device by one Embodiment.

  With reference to the drawings, a motor driving device for detecting an inverter having a large leakage current will be described below. In the drawings, similar members are denoted by the same reference numerals. Moreover, what attached | subjected the same referential mark in a different drawing shall mean that it is a component which has the same function. In order to facilitate understanding, the scales of these drawings are appropriately changed. In general, the leakage current is generated more or less when the motor is driven. However, in the present disclosure, “a leakage current that causes malfunction or damage has occurred” is simply referred to as “a leakage current has occurred. ”Or“ There is leakage current ”and“ No leakage current causing malfunction or damage ”is simply expressed as“ No leakage current ”or“ No leakage current ”. There are things to do.

  FIG. 1 is a diagram illustrating a motor drive device according to an embodiment. Here, as an example, a case where a plurality of three-phase AC motors 2-n (n is a positive integer) is controlled by the motor driving device 1 will be described, but the present invention is particularly limited with respect to the types of motors 2-n. For example, it may be an induction motor or a synchronous motor. In the embodiment shown in FIG. 1, the AC power supply 3 is a three-phase motor, and the motor 2-n is a three-phase AC motor. Application examples when the AC power supply 3 is a single phase and when the motor 2-n is a single-phase AC motor will be described later.

  As shown in FIG. 1, a motor drive device 1 according to an embodiment includes a forward converter 11, an inverse converter 12-n (n is a positive integer), a diagnostic command unit 13, and a noise absorbing circuit 14. , A temperature measurement unit 15, a storage unit 16, and a leakage current determination unit 17. Here, each phase of the three-phase AC power supply 3 is R phase, S phase, and T phase, and N is a grounding point.

  The motor drive device 1 according to one embodiment has one forward converter 11. The forward converter 11 converts AC power supplied from the three-phase AC power supply 3 into DC power and outputs the DC power. Examples of the forward converter 11 include a diode rectifier circuit, a 120-degree conduction rectifier circuit, or a PWM switching control type rectifier circuit having a switching element therein. When the forward converter 11 is a diode rectifier circuit, the AC current supplied from the AC power supply 3 side is rectified and a DC current is output to the DC link on the DC side. When the forward converter 11 is a 120-degree conduction type rectifier circuit or a PWM switching control type rectifier circuit, the forward converter 11 converts AC power supplied from the AC power supply 3 side into DC power to the DC side. When the motor is decelerated, it can be realized as a power converter that can convert the direct current power supplied from the DC link into alternating current power and output the alternating current power to the alternating current power supply 3 side and can be converted into AC and AC bidirectional directions. When the forward converter 11 is a PWM switching control type rectifier circuit, the forward converter 11 includes a switching element and a bridge circuit of a diode connected in reverse parallel thereto. In this case, examples of the switching element include an IGBT, a thyristor, a GTO (Gate Turn-OFF thyristor), a transistor, and the like, but the type of the switching element itself does not limit the present invention. It may be a switching element.

  A DC link capacitor (also referred to as a smoothing capacitor) 20 is provided in the DC link that connects the DC output side of the forward converter 11 and the DC input side of the inverse converter 12-n. The DC link capacitor 20 has a function of accumulating DC power in the DC link and a function of suppressing the pulsation of the DC output of the forward converter 11.

  The inverse converters 12-n supply the drive power individually to the plurality of motors 2-n to drive and control the motor 2-n. n).

  The reverse converter 12-n is connected to the DC link, and each switching element is on / off controlled based on a switching command received from a host controller (not shown), whereby the DC power of the DC link and the motor 2-n are controlled. Power is converted between AC power that is drive power or regenerative power. The inverse converter 12-n includes a switching element and a bridge circuit of a diode connected in antiparallel to the switching element, and each switching element is on / off controlled based on, for example, a PWM switching control method. In this embodiment, since the motor 2-n connected to the motor drive device 1 is a three-phase AC motor, the inverse converter 12-n is configured as a three-phase bridge circuit. Examples of the switching element include an IGBT, a thyristor, a GTO, and a transistor. However, the type of the switching element itself does not limit the present invention, and other switching elements may be used.

  In the normal operation mode for the motor 2-n, the reverse converter 12-n switches the internal switching element based on the switching command received from the host controller, and is supplied from the forward converter 11 via the DC link. The DC power is converted into AC power having a desired voltage and a desired frequency for driving the motor 2-n (inverse conversion operation). As a result, the motor 2-n operates based on the supplied AC power having variable voltage and variable frequency. In addition, regenerative power is generated when the motor 2-n decelerates, but the internal switching element is switched based on the switching command received from the host controller, and the AC regenerative power generated by the motor 2-n is converted to DC power. To return to the DC link (forward conversion operation). Although details will be described later, in a mode (hereinafter referred to as “diagnostic mode”) in which an inverse converter having a large leakage current is determined (specified) instead of a normal operation mode for the motor 2-n. The command unit 13 sequentially performs the process of performing the power conversion operation on only one of the plurality of inverse converters 12-n for each inverse converter 2-n.

  The diagnosis command unit 13 performs a process of instructing only one of the plurality of inverse converters 12-n to perform the power conversion operation in the diagnosis mode. It carries out sequentially every time. More specifically, the diagnostic command unit 13 switches the DC power supplied from the forward converter 11 via the DC link by switching the internal switching element to one inverter. A command (on / off switching command) for converting to the drive power is output, and the DC power supplied from the forward converter 11 is not converted to AC power for an inverter other than the one inverter. A command to be executed (that is, a switching command only for OFF) is output. The diagnostic command unit 13 performs this command processing for each of the plurality of inverse converters 12-n. Therefore, in the diagnosis mode, only one inverse converter performs the power conversion operation at a certain point in time, and therefore, only the motor connected to the one inverse converter that performs the power conversion operation is driven. Become.

  The noise absorption circuit 14 includes a resistor 31 and a capacitor 32 and absorbs noise generated between the AC power supply 3 and the forward converter 11. Since the motor 2-n is an inductive load, when the switching element in the inverter 12-n is turned on / off, instantaneous high voltage noise called “surge” having a large energy is generated by the back electromotive force. Since the high voltage noise may damage each element of the inverse converter 12-n or malfunction, the noise absorbing circuit 14 is installed on the AC input side of the forward converter 11 in order to prevent this. In the noise absorption circuit 14, the high voltage noise is received by the capacitor 32 and consumed by the resistor 31. There are various configurations of the noise absorbing circuit 14, and an example is shown in FIG. FIG. 2 is a diagram illustrating a first form of the noise absorption circuit in the motor drive device according to the embodiment. The noise absorption circuit 14 according to the first embodiment is configured by delta-connecting a set of a resistor 31 and a capacitor 32 connected in series, and an R phase, an S phase, and a T phase between the AC power supply 3 and the forward converter 11. Connected between each phase.

  The temperature measuring unit 15 measures the temperature of the resistor 31 in the noise absorbing circuit 14. The sensor portion of the temperature measurement unit 15 is preferably installed as close as possible to the resistor 31. More specifically, the sensor portion of the temperature measurement unit 15 is directly attached to the resistor 31 or is installed via some member with respect to the resistor 31, for example, and the resistor 31 is connected to the noise absorbing circuit 14. If it is housed in a case, it is installed on that case.

  The storage unit 16 stores the temperature measured by the temperature measurement unit 15 in association with the inverse converter that has been instructed to perform the power conversion operation by the diagnosis command unit 13 when the temperature is measured. . As described above, at a certain point in the diagnostic mode, only one inverse converter performs the power conversion operation, so that only the motor connected to the one inverse converter that performs the power conversion operation is driven. Will be. Therefore, the temperature measurement unit 15 measures the temperature of the resistor 31 when the motor connected to the inverse converter performing the power conversion operation is driving, and the storage unit 16 measures this temperature. The temperature is stored together with the identification information of the inverse converter that has been commanded to perform the power conversion operation by the diagnostic command unit 13. The storage unit 16 is configured by, for example, an electrically erasable / recordable non-volatile memory such as EEPROM (registered trademark), or a random access memory such as DRAM or SRAM that can be read and written at high speed. The Alternatively, the storage unit 16 may be provided in a partial area of the storage device used when the motor drive device 1 drives the motor 2-n in the normal operation mode.

  Leakage current determination unit 17 is the largest reverse converter that has been commanded to perform power conversion operation by diagnostic command unit 13 when the highest temperature among the temperatures stored in storage unit 16 is measured. It is determined as an inverse converter in which leakage current has occurred. The leakage current determination process performed by the leakage current determination unit 17 will be described in more detail with reference to FIG.

  Each motor 2-n, motor power cable, and the like have stray capacitance. In FIG. 2, stray capacitance is indicated by reference numeral 200. When high-speed PWM switching control is performed on the switching element in the inverter 2-n to supply AC power for driving the motor 2-n, the AC power source 3, the forward converter 11, and the inverter are converted. A leakage current flows through 2-n and the stray capacitance 200. In FIG. 2, an example of a path through which a leakage current resulting from driving of the motor 2-1 flows is indicated by a thick dashed arrow. The current path shown in FIG. 2 is merely an example. Actually, leakage due to driving of the motor 2-1 is caused by a combination with the on / off state of each switching element in the upper arm and lower arm of the inverter 12-1. The current path through which the current flows changes every moment.

  When a leakage current resulting from the driving of the motor 2-1 occurs, a part of the leakage current also flows to the noise absorption circuit 14. In FIG. 2, for example, when a leakage current caused by driving of the motor 2-1 flows through a current path indicated by a thick dashed arrow, an example of a path through which the leakage current flows in the noise absorption circuit 14 is indicated by a thick dashed line. Shown with an arrow. Note that if the current path through which the leakage current resulting from the driving of the motor 2-1 changes, the current path of the leakage current in the noise absorbing circuit 14 also changes accordingly.

  The high-frequency leakage current flowing in the noise absorbing circuit 14 is consumed by the resistor 31 in the noise absorbing circuit 14, and the resistor 31 generates heat accordingly. The temperature rise value of the resistor 31 is substantially proportional to the heat loss (power consumption) in the resistor 31. When the resistance value of the resistor 31 in the noise absorbing circuit 14 is R, the magnitude of the leakage current flowing through the resistor 31 is i, and the temperature increase coefficient for heat loss in the resistor 31 is k, the temperature increase value ΔT of the resistor 31 is It is expressed as Equation 1.

  When formula 1 is transformed, formula 2 is obtained.

  From Equation 2, it can be seen that if the temperature rise value ΔT in the resistor 31 is known, the magnitude i of the leakage current flowing through the resistor 31 can be estimated.

  As described above, in the diagnostic mode, only one inverse converter performs the power conversion operation at a certain point in time, so the temperature measurement unit 15 performs one power conversion operation among the plurality of inverse converters. The temperature when the motor connected to the inverse converter is being driven is measured. If the inverse converters that perform the power conversion operation in the diagnostic mode are sequentially changed, when each of the inverse converters 2-n is operated as a single unit, the leakage current caused by the driving of the motor 2-n occurs. The temperature rise value ΔT in the resistor 31 can be known. As can be seen from Equation 2, the greater the temperature rise value ΔT in the resistor 31, the greater the amount of current flowing in the leakage current flowing in the resistor 31. Therefore, the leakage current determination unit 17 in the motor drive device 1 according to the embodiment performs power conversion operation by the diagnosis command unit 13 when the highest temperature among the temperatures stored in the storage unit 16 is measured in the diagnosis mode. The inverse converter that has been commanded to perform is determined as the inverse converter that has generated the largest leakage current.

  As shown in FIG. 2, when there are a plurality of resistors 31 in the noise absorbing circuit 14, it is preferable to measure the temperatures of all the resistors 31 by the temperature measuring unit 15. The reason is as follows. For example, an electrical device such as a device for generating a DC control power source is connected to two phases of the three phases of the cable connecting the AC power source 3 and the motor driving device 1, thereby the motor driving device. Some three-phase imbalance may occur on the AC input side of 1. Due to this three-phase imbalance, the temperature rising tendency of each resistor 31 in the noise absorbing circuit 14 is different. If the temperature measurement unit 15 measures the temperature of all the resistors 31 and performs the determination process by the leakage current determination unit 17 based on the largest temperature increase value as a result of the measurement, the largest leakage current is generated more accurately. An inverse converter can be detected.

  Based on the determination result by the leakage current determination part 17 mentioned above, the identification information of the reverse converter determined that the largest leakage current generate | occur | produced can be alert | reported with respect to a user. A notification unit that notifies whether or not a leakage current has occurred will be described with reference to FIG.

  FIG. 3 is a block diagram illustrating a case where a notification unit is connected to the leakage current determination unit. As shown in FIG. 3, the motor drive device 1 further includes a notification unit 18 that notifies the identification information of the inverse converter that has been determined by the leakage current determination unit 17 that the largest leakage current has occurred. Examples of the notification unit 18 include a display such as a personal computer, a portable terminal, and a touch panel, a display attached to a numerical control device (not shown) provided in the motor driving device 1, and the largest leakage current is generated. The identification information of the determined inverse converter is displayed on the display using, for example, characters or pictures. Further, for example, the notification unit 18 may be realized by an acoustic device that emits sound such as sound, a speaker, a buzzer, a chime, and the identification information of the inverse converter that is determined to have generated the largest leakage current. Notify by sound. Alternatively, the notification unit 18 may take a form that is printed out and displayed on a sheet of paper using a printer. For example, the identification information of the inverse converter that has been determined to have the largest leakage current is displayed along with the time of occurrence. It may be displayed. Alternatively, the notification unit 18 may be realized by appropriately combining these. In addition, the data regarding the determination result output by the leakage current determination unit 17 may be stored in a storage device, and the data may be used for further use.

  Based on the determination result of the leakage current determination unit 17, the user of the motor drive device 1 can easily and accurately grasp the inverse converter determined to have the largest leakage current. For example, a user who has been able to grasp “the reverse converter determined to have generated the largest leakage current” is connected to a motor connected to the reverse converter, for example, via the notification unit 18. The design may be changed such that the cable or the cable connecting the AC power supply 3 and the motor drive device 1 is thickened or the noise absorbing circuit 14 is replaced with one having a different resistance value of the resistor 31 or a capacitor 32 having a different capacitance. it can.

  Note that the diagnostic command unit 13, the storage unit 16, and the leakage current determination unit 17 described above may be configured in, for example, a software program format, or may be configured in a combination of various electronic circuits and software programs. For example, when these are constructed in the software program format, a computer for operating according to the software program is provided, or the software program is operated by an arithmetic processing unit in the numerical controller connected to the motor drive device 1. Thus, the function of each unit described above can be realized. Alternatively, the diagnostic command unit 13, the storage unit 16, and the leakage current determination unit 17 may be realized as a semiconductor integrated circuit in which a software program for realizing the function of each unit is written.

  Further, for example, when a plurality of motor driving devices 1 are provided and the control system of each motor driving device 1 is connected via a communication network, the determination result of the leakage current determination unit 17 in each motor driving device 1 It may be shared on the server.

  For example, when a plurality of manufacturing cells including a machine tool including the motor driving device 1 are connected via a communication network, the determination result of the leakage current determination unit 17 in each motor driving device 1 It may be shared by the cell controller in the system or the production management apparatus in the higher level of the cell controller.

  A manufacturing cell is a set of a plurality of machine tools that manufacture products flexibly. The production cell is constructed by, for example, a plurality or a plurality of types of machine tools, but the number of machine tools in the production cell is not limited. For example, the manufacturing cell may be a manufacturing line that becomes a final product by sequentially processing a certain workpiece by a plurality of machine tools. In addition, for example, the manufacturing cell is obtained by combining two or more workpieces (parts) processed by each of two or more machine tools with another machine tool in the course of the manufacturing process. ) May be a production line that completes. Further, for example, a final workpiece (product) may be completed by combining two or more workpieces processed by two or more manufacturing cells. The manufacturing cell and the cell controller are interconnected to be communicable via a communication network such as an intranet. The production cell is arranged in a factory for producing a product. On the other hand, the cell controller may be arranged in a factory where the manufacturing cell is arranged, or may be arranged in a building different from the factory. For example, the cell controller may be arranged in another building on the site of a factory where the manufacturing cell is arranged.

  A production management device is provided above the cell controller. The production management device is connected to the cell controller so as to be able to communicate with each other, and instructs the cell controller to produce a production plan. For example, the production management device may be arranged in an office in a remote place from the factory. In this case, the cell controller and the production management apparatus are interconnected so as to be communicable via, for example, an Internet communication network.

  In such a production system, “the identification information of the inverse converter determined to have the largest leakage current” may be displayed on the display device provided in the cell controller or the production management device. Alternatively, instead of the display device or together with the display device, an alarm sound or a buzzer may be generated by an acoustic device to notify the determination result to the user. Thereby, the worker and manager who work in a factory can grasp | ascertain easily the motor drive device 1 which should perform the design change for the purpose of leakage current reduction.

  FIG. 4 is a flowchart illustrating an operation flow of the motor drive device according to the embodiment.

  The process of detecting the reverse converter in which the largest leakage current is generated from among the multiple reverse converters is executed when the motor drive device 1 is in the diagnostic mode. When the motor drive device 1 is in the normal operation mode for the motor 2-n, the mode is switched to the diagnosis mode. The switching from the operation mode to the diagnosis mode is performed by, for example, a specific key operation on the operation terminal of the numerical controller connected to the motor drive device 1, a switching instruction from a cell controller above the numerical controller, This is performed by a switching instruction from a production management apparatus in the factory. In the diagnostic mode, in step S101, the diagnostic command unit 13 causes the switching element inside the single inverter to perform a switching operation and is supplied from the forward converter 11 via the DC link. Is converted to AC drive power (on / off switching command), and the DC power supplied from the forward converter 11 is converted to AC power for an inverter other than the one inverter. A command to prevent conversion (that is, a switching command only for OFF) is output. As a result, only one inverse converter that has received a command from the diagnostic command unit 13 performs a power conversion operation, and only the motor connected to the one inverse converter is driven.

  High-speed PWM switching control is performed in one inverter that has received a command from the diagnostic command unit 13, thereby passing through the AC power supply 3, the forward converter 11, the one inverter and the stray capacitance 200. As a result, a leakage current flows. A part of this leakage current also flows through the noise absorbing circuit 14. The high-frequency leakage current flowing in the noise absorbing circuit 14 is consumed by the resistor 31 in the noise absorbing circuit 14, and the resistor 31 generates heat accordingly. The temperature measurement unit 15 measures the temperature of the resistor 31 at this time (step S102).

  In step S <b> 103, the storage unit 16 stores the temperature of the resistor 31 measured by the temperature measurement unit 15 together with the identification information of the inverse converter that has been commanded to perform the power conversion operation by the diagnostic command unit 13.

  In subsequent step S104, the leakage current determination unit 17 performs processing in which the temperature measurement unit 15 measures the temperature of the resistor 31 when one of the inverse converters that has received the command from the diagnostic command unit 13 is performing a power conversion operation. Is executed for all the inverse converters. If it is determined that there is an inverse converter that has not been executed, the process returns to step S101. By sequentially repeating the processes of steps S101 to S104 for all the inverse converters, the storage unit 16 stores the temperature measured by the temperature measuring unit 15 and the diagnostic command unit when the temperature is measured. 13 and the identification information of the inverse converter that has been instructed to perform the power conversion operation is stored in association with each other. Note that the execution subject of the determination process in step S104 may be the diagnostic instruction unit 13 instead of the leakage current determination unit 17 described here.

  In step S105, the leakage current determination unit 17 has been instructed to perform a power conversion operation by the diagnostic command unit 13 when the highest temperature among the temperatures stored in the storage unit 16 is measured. Is determined as the inverse converter in which the largest leakage current is generated. The determination result by the leakage current determination unit 17 is notified to the user by the notification unit 18.

  The motor drive device 1 according to the above-described embodiment can be applied to various forms of noise absorbing circuits, forward converters, inverse converters, and motors. Hereafter, some will be described with reference to FIGS. In addition, about the form shown in FIGS. 5-9, since it is the same as that of the component shown in FIG. 1 about components other than the component mentioned especially, the same code | symbol is attached | subjected to the same component and the said structure A detailed description of the elements is omitted.

  FIG. 5 is a diagram illustrating a second form of the noise absorbing circuit in the motor drive device according to the embodiment. As shown in FIG. 5, when the noise absorbing circuit 14 is provided between two phases on the AC input side of the motor driving device 1 (between the R phase and the T phase in the example of FIG. 5), the temperature of the resistor 31 in the noise absorbing circuit 14. Is measured by the temperature measurement unit 15, and the leakage current determination unit 17 may perform a leakage current determination process based on the measurement result.

  FIG. 6 is a diagram illustrating a third form of the noise absorption circuit in the motor drive device according to the embodiment. As shown in FIG. 6, when the noise absorption circuit 14 is provided between one phase of the AC input side of the motor drive device 1 and the ground (between the R phase and the ground in the example of FIG. 6), noise absorption is performed. The temperature of the resistor 31 in the circuit 14 is measured by the temperature measurement unit 15, and the leakage current determination unit 17 may perform a leakage current determination process based on the measurement result.

  FIG. 7 is a diagram illustrating a fourth form of the noise absorption circuit in the motor drive device according to the embodiment. As shown in FIG. 7, a set of a resistor 31 and a capacitor 32 connected in series is star-connected (Y-connected) to form a noise absorption circuit 14, and a set of a resistor 31 and a capacitor 32 connected in series is formed. When one end is connected to the R phase, the S phase, and the T phase and the other end is connected to the ground, the temperature of each resistor 31 in the noise absorbing circuit 14 is measured by the temperature measurement unit 15, and based on this measurement result The leakage current determination unit 17 may perform a leakage current determination process.

  FIG. 8 is a diagram illustrating another form of the forward converter in the motor drive device according to the embodiment. As shown in FIG. 8, when the AC power supply 3 is a single-phase power supply, the forward converter 41 is configured by a single-phase rectifier circuit, and the noise absorption circuit 14 is between two phases on the AC input side of the motor driving device 1 (FIG. 8). In this example, it is provided between the R phase and the T phase. In this case, the temperature of the resistor 31 in the noise absorption circuit 14 is measured by the temperature measurement unit 15, and the leakage current determination unit 17 may perform a leakage current determination process based on the measurement result.

  FIG. 9 is a diagram illustrating another form of the inverse converter in the motor drive device according to the embodiment. As shown in FIG. 9, when the motor 2-n is a single-phase AC motor, the reverse converter 42-n is configured by a single-phase reverse converter. When the noise absorbing circuit 14 similar to that shown in FIG. 1 is provided, the temperature of the resistor 31 in the noise absorbing circuit 14 is measured by the temperature measuring unit 15, and the leakage current determining unit 17 leaks based on the measurement result. What is necessary is just to perform an electric current determination process.

  Thus, the motor drive device 1 according to the embodiment can be applied to various forms of noise absorption circuits, forward converters, inverse converters, and motors. The motor drive device 1 may be realized by appropriately combining the above-described components. For example, the plurality of motors provided on the AC output side of the reverse converter may be both a single-phase AC motor and a three-phase AC motor. In this case, a single-phase AC converter is connected to the single-phase AC motor. A three-phase reverse converter is connected to the three-phase AC motor.

DESCRIPTION OF SYMBOLS 1 Motor drive device 2-1, 2-2, 2-3, 2-n Motor 3 AC power supply 11, 41 Forward converter 12-1, 12-2, 12-3, 12-n, 42-1, 42 -2 inverse converter 13 diagnostic command unit 14 noise absorption circuit 15 temperature measurement unit 16 storage unit 17 leakage current determination unit 18 notification unit 20 DC link capacitor 31 resistor 32 capacitor 200 stray capacitance

Claims (2)

A forward converter for converting AC power supplied from an AC power source into DC power and outputting the DC power;
A plurality of inverse converters, each provided for each motor, for performing a power conversion operation for converting the DC power output from the forward converter into AC power for driving the motor according to the received command;
A diagnostic command unit that sequentially performs the process of commanding the power conversion operation only for one of the plurality of inverse converters, for each of the inverse converters, and
A noise absorbing circuit that has a resistor and a capacitor and absorbs noise generated between the AC power source and the forward converter;
A temperature measuring unit for measuring the temperature of the resistor;
A storage unit that stores the temperature measured by the temperature measurement unit in association with the inverse converter that has been commanded to perform the power conversion operation by the diagnostic command unit when the temperature is measured;
When the highest temperature among the temperatures stored in the storage unit is measured, the reverse converter that has been commanded to perform the power conversion operation by the diagnostic command unit is reversed with the largest leakage current. A leakage current determination unit for determining as a converter;
A motor drive device comprising:   The motor drive device according to claim 1, further comprising a notification unit that notifies identification information of an inverse converter that has been determined by the leakage current determination unit to have generated the largest leakage current.

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