Power conversion device, cooling abnormality determination device, and cooling abnormality determination method

Abstract

The present invention provides a power conversion device capable of more appropriately determining an abnormality related to the cooling performance of a power device with respect to a cooling structure portion such as a heat sink of the power conversion device. The power conversion device (100) according to one embodiment of the present invention includes: a power device (SD, SW); a cooling structure portion (190) for dissipating heat of the power device; a cooling fan (180) for blowing air to the cooling structure portion (190); and a control device (140) for determining an abnormality related to the cooling performance of the cooling structure portion (190) based on a temperature difference (Y) between the temperature (Tf) of the cooling structure portion (190), i.e., the heat sink portion (194), and the temperature of the air inside the housing of the power conversion device (100), i.e., the internal air temperature (Ta).

Description

Technical Field

[0001] The present invention relates to a power conversion device and the like. Background Art

[0002] For example, in a power conversion device that converts power input from the outside into power of a specified voltage and a specified frequency to drive a load device, there is known a method for determining a cooling abnormality caused by a blockage or the like in a cooling structure portion for dissipating heat of a power device (see Patent Documents 1 and 2).

[0003] <Prior Art Documents>

[0004] <Patent Documents>

[0005] Patent Document 1: Japanese Patent No. 6591642

[0006] Patent Document 2: Japanese Patent No. 5593051 Summary of the Invention

[0007] <Problems to be Solved by the Invention>

[0008] However, in Patent Document 1 described above, a cooling abnormality caused by a blockage or the like of a heat sink is determined based on changes in temperatures at a plurality of locations measured within the power conversion device. Therefore, among the changes in the measured temperatures, there is a possibility that the influence caused by a change in the load state of the power conversion device overlaps, and thus there is a possibility that the accuracy of determining a cooling abnormality of the heat sink decreases.

[0009] In addition, in Patent Document 2 described above, when a heating state occurs, the power conversion device is forcibly stopped, and a cooling abnormality caused by a blockage or the like of an air intake port for sucking air toward the heat sink is determined using not only the temperature inside the power conversion device but also the load state of the power conversion device. Therefore, although it is possible to expect an improvement in determination accuracy by considering the load state of the power conversion device, as a prerequisite, it is premised on the occurrence of a heating abnormality in which the power conversion device is forcibly stopped, and it is not possible to determine a cooling abnormality at a stage before the power conversion device is forcibly stopped.

[0010] Therefore, in view of the above problems, an object of the present invention is to provide a technique capable of more appropriately determining an abnormality related to the cooling performance of a power device based on a cooling structure portion such as a heat sink of a power conversion device.

[0011] <Means for Solving the Problems>

[0012] To achieve the above object, in one embodiment of the present invention, there is provided a power conversion device including:

[0013] Power device;

[0014] A cooling structure portion for dissipating heat of the above power device;

[0015] A blower unit for blowing air to the above cooling structure portion; and

[0016] A determination unit that makes a determination related to an abnormality in the cooling performance of the above cooling structure portion based on the temperature difference between the temperature of the above cooling structure portion and the temperature of the air inside the power conversion device.

[0017] Further, in another embodiment of the present invention, there is provided a cooling abnormality determination device, which is a cooling abnormality determination device for a power conversion device, and the power conversion device includes:

[0018] Power device;

[0019] A cooling structure portion for dissipating heat of the above power device; and

[0020] A blower unit for blowing air to the above cooling structure portion,

[0021] The cooling abnormality determination device makes a determination related to an abnormality in the cooling performance of the above cooling structure portion based on the temperature difference between the temperature of the above cooling structure portion and the temperature of the air inside the power conversion device.

[0022] Further, in another embodiment of the present invention, there is provided a cooling abnormality determination method, which is a cooling abnormality determination method for a power conversion device, and the power conversion device includes:

[0023] Power device;

[0024] A cooling structure portion for dissipating heat of the above power device; and

[0025] A blower unit for blowing air to the above cooling structure portion,

[0026] The cooling abnormality determination method makes a determination related to an abnormality in the cooling performance of the above cooling structure portion based on the temperature difference between the temperature of the above cooling structure portion and the temperature of the air inside the power conversion device.

[0027] <Effects of the Invention>

[0028] According to the above embodiments, it is possible to more appropriately determine an abnormality related to the cooling performance of a power device caused by a cooling structure portion such as a heat sink of a power conversion device. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a diagram showing an example of the configuration of a cooling abnormality determination system.

[0030] Figure 2 This is a diagram showing an example of the configuration of a control device.

[0031] Figure 3 This is a schematic diagram showing an example of the cooling structure of a power conversion device.

[0032] Figure 4 This is a flowchart schematically showing an example of data acquisition processing related to the determination of cooling abnormality.

[0033] Figure 5 This is a flowchart schematically showing an example of end processing related to the determination of cooling abnormality.

[0034] Figure 6 This is a flowchart schematically showing an example of start processing related to the determination of cooling abnormality.

[0035] Figure 7 This is a flowchart schematically showing an example of the determination process of cooling abnormality.

[0036] Figure 8 This is a flowchart schematically showing an example of the determination process of cooling abnormality mitigation.

[0037] Figure 9 This is a diagram for explaining an example of the operation related to the determination of cooling abnormality based on a control device.

[0038] Figure 10 This is a flowchart schematically showing another example of data acquisition processing related to the determination of cooling abnormality.

[0039] Figure 11 This is a diagram for explaining another example of the operation related to the determination of cooling abnormality based on a control device.

[0040] Figure 12 This is a flowchart schematically showing another example of the determination process of cooling abnormality.

[0041] Explanation of Reference Numerals

[0042] 1 Cooling Abnormality Determination System

[0043] 100 Power Conversion Device

[0044] 110 Rectifier Circuit

[0045] 110A Circuit Board

[0046] 120 Smoothing Circuit

[0047] 130 Inverter Circuit

[0048] 130A Circuit board

[0049] 140 Control device (judgment unit, cooling abnormality judgment device)

[0050] 141 CPU

[0051] 142 Memory device

[0052] 142A, 142B RAM

[0053] 143 Auxiliary storage device

[0054] 143A ROM

[0055] 143B EEPROM (storage unit)

[0056] 144 Interface

[0057] 150 Sensor

[0058] 160 Display device (notification unit, display unit)

[0059] 170 Communication device (notification unit)

[0060] 180 Cooling fan (air supply unit)

[0061] 190 Cooling structure unit

[0062] 192 Heat sink base

[0063] 194 Heat sink part

[0064] 194A Heat sink

[0065] 200 Arithmetic device (second external device, third external device, cooling abnormality judgment device)

[0066] 300 Terminal device (first external device, third external device, cooling abnormality judgment device)

[0067] 310 Display part

[0068] M Motor

[0069] PS Commercial power supply

[0070] RB Ring buffer

[0071] SD Semiconductor diode (power device)

[0072] SW Semiconductor switch (power device) Detailed implementation mode

[0073] Hereinafter, the implementation mode will be described with reference to the accompanying drawings.

[0074] [Configuration of Cooling Abnormality Judgment System]

[0075] First, refer to Figure 1 and Figure 2 to describe the configuration of the cooling abnormality judgment system 1 of this embodiment.

[0076] Figure 1 is a diagram showing an example of the configuration of the cooling abnormality judgment system 1 of this embodiment. Figure 2 is a diagram showing an example of the configuration of the control device 140 in the cooling abnormality judgment system 1 of this embodiment.

[0077] The cooling abnormality judgment system 1 of this embodiment is used to judge the presence or absence of an abnormality related to the cooling performance of the power conversion device 100.

[0078] As Figure 1 shown, the cooling abnormality judgment system 1 includes a power conversion device 100, an arithmetic device 200, and a terminal device 300.

[0079] The power conversion device 100 converts three-phase alternating current (for example, R phase, S phase, and T phase) input from a commercial power supply PS into three-phase alternating current (for example, U phase, V phase, and W phase) having a specified voltage and a specified frequency, thereby driving the motor M.

[0080] Based on the three-phase alternating current output from the power conversion device 100, the motor M, for example, motor-drives a specified machine such as a winding machine provided in a textile factory.

[0081] It should be noted that the power conversion device 100 can generate three-phase alternating current for driving the motor M based on three-phase alternating current input from a power source other than the commercial power supply. In addition, the power conversion device 100 can generate three-phase alternating current for driving the motor M based on the power input from a DC power source. In this case, the direct current is input to the DC connection part (positive line PL and negative line NL) between the following rectifier circuit 110 and inverter circuit 130.

[0082] The power conversion device 100 includes a rectifier circuit 110, a smoothing circuit 120, an inverter circuit 130, a control device 140, a sensor 150, a display device 160, a communication device 170, and a cooling fan 180.

[0083] The rectifier circuit 110 is configured to rectify the three-phase alternating current of the R phase, S phase, and T phase input from the commercial power supply PS, so as to be able to output direct current. The positive and negative output terminals of the rectifier circuit 110 are respectively connected to one end of the positive line PL and the negative line NL, and the direct current is output to the smoothing circuit 120 through the positive line PL and the negative line NL. The rectifier circuit 110 includes, for example, six semiconductor diodes SD (an example of a power device) (refer to Figure 3 ), which is a bridge full-wave rectifier circuit in which three sets of series-connected bodies of two semiconductor diodes SD constituting the upper and lower bridge arms are connected in parallel.

[0084] The smoothing circuit 120 is used to suppress the pulsation of the direct current output from the rectifier circuit 110 and the direct current regenerated from the inverter circuit 130, so as to smooth it.

[0085] The smoothing circuit 120 includes, for example, smoothing capacitors.

[0086] The smoothing capacitor can be provided in parallel with the rectifier circuit 110 and the inverter circuit 130 in the path connecting the positive line PL and the negative line NL.

[0087] The smoothing capacitor appropriately smooths the direct current output from the rectifier circuit 110 and the direct current output (regenerated) from the inverter circuit 130 while repeating charging and discharging.

[0088] The smoothing capacitor can be one. In addition, multiple smoothing capacitors can be provided. The multiple smoothing capacitors can be connected in parallel or in series between the positive line PL and the negative line NL. In addition, the multiple smoothing capacitors can be configured in such a way that a series-connected body of two or more smoothing capacitors is connected in parallel between the positive line PL and the negative line NL.

[0089] In addition, the smoothing circuit 120 includes, for example, a reactor.

[0090] The reactor can be provided on the positive line PL between the rectifier circuit 110 and the smoothing capacitor (specifically, the branch point of the path where the smoothing capacitor is arranged).

[0091] The reactor appropriately smooths the direct current output from the rectifier circuit 110 and the direct current output (regenerated) from the inverter circuit 130 while generating a voltage in a manner that hinders the change of current.

[0092] In the inverter circuit 130, its positive and negative input terminals are connected to the other ends of the positive line PL and the negative line NL. The inverter circuit 130 uses a semiconductor switch SW (an example of a power device) (refer to Figure 3) The switching operation of the [device] converts the direct current supplied from the self-smoothing circuit 120 into three-phase alternating current (e.g., U-phase, V-phase, and W-phase) with a specified frequency and voltage and outputs it to the motor M. The semiconductor switch SW can be, for example, an IGBT (Insulated Gate Bipolar Transistor) or a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) made of silicon (Si). Additionally, the semiconductor switch SW can be a semiconductor device using wide-bandgap semiconductors such as silicon carbide (SiC) or gallium nitride (GaN).

[0093] The inverter circuit 130 includes, for example, six semiconductor switches SW and is configured as a bridge circuit including a series connection body (switch bridge arm) in which three sets of two semiconductor switches SW constituting upper and lower bridge arms are connected in parallel between the positive line PL and the negative line NL. Also, the inverter circuit 130 can output three-phase alternating current through the U-phase line, V-phase line, and W-phase line led out from the connection points of the three sets of upper and lower bridge arms. Additionally, freewheeling diodes can be respectively connected in parallel to the six semiconductor switches SW.

[0094] The control device 140 performs control related to the power conversion device 100.

[0095] The function of the control device 140 can be implemented by any hardware or a combination of any hardware and software.

[0096] As Figure 2 shown, the control device 140 is centered around a computer including a CPU 141 (Central Processing Unit), a memory device 142, a non-volatile auxiliary storage device 143, and an interface 144. The control device 140 performs various controls by loading the program installed in the auxiliary storage device 143 into the memory device 142 and causing the CPU 141 to execute the program. Additionally, the control device 140 receives external signals through the interface 144 and outputs (sends) signals to the outside.

[0097] As Figure 2 shown, the memory device 142 includes RAMs (Random Access Memories) 142A and 142B.

[0098] The auxiliary storage device 143 includes a ROM (Read Only Memory) 143A and an EEPROM (Electrically Erasable Programmable Read-Only Memory) 143B. In the EEPROM 143B (an example of a storage unit), a ring buffer RB described later is set.

[0099] It should be noted that the ring buffer RB can be set to the RAM 142A or the RAM 142B.

[0100] The control device 140 (an example of a determination unit and a cooling abnormality determination device) outputs a drive signal to the inverter circuit 130 (specifically, the gates of the respective semiconductor switches SW), and uses the inverter circuit 130 to drive the motor M so as to satisfy a specified operating condition. In other words, the control device 140 generates a control signal for driving the motor M according to the specified operating condition, and outputs it to the inverter circuit 130.

[0101] In addition, the control device 140 determines the presence or absence of an abnormality related to the cooling performance of the power conversion device 100. Specifically, it determines the presence or absence of an abnormality related to the cooling performance of the cooling structure unit 190 for dissipating heat generated by the loss when the semiconductor diode SD and the semiconductor switch SW described later are energized. Details will be described later.

[0102] The sensor 150 acquires detection information related to the operating state (working state) of the power conversion device 100. The sensor 150 is connected to the control device 140 through, for example, a one-to-one communication line or the like, and a signal corresponding to the detection information (hereinafter referred to as a "detection signal") enters the control device 140. Thereby, the control device 140 can perform control related to the power conversion device 100 based on the detection signal of the sensor 150.

[0103] The sensor 150 includes, for example, various temperature sensors. Among the temperature sensors, for example, a heat sink temperature sensor for detecting the temperature of the heat sink portion 194 (hereinafter referred to as the "heat sink temperature") Tf described later can be included. In addition, among the temperature sensors, for example, an internal air temperature sensor for detecting the temperature of the air inside the housing of the power conversion device 100 (hereinafter referred to as the "internal air temperature") Ta can be included.

[0104] In addition, the sensor 150 includes, for example, various current sensors, voltage sensors, etc. Among the current sensors, for example, a load current sensor for detecting the load current IL output to the motor M can be included.

[0105] The display device 160 (an example of a notification unit and a display unit) is provided, for example, on the outer surface of the housing of the power conversion device 100. The display device 160 is used to display information related to the operating state (working state) of the power conversion device 100 under the control of the control device 140.

[0106] It should be noted that the display device 160 can be provided outside the housing of the power conversion device 100. For example, it can be provided on the surface (outer surface) of a specified machine that is electrically driven by the motor M.

[0107] The communication device 170 (an example of a notification unit) communicates with external devices of the power conversion device 100, such as the arithmetic device 200 and the terminal device 300, through a specified communication line.

[0108] The specified communication line can be, for example, a one-to-one communication line. In addition, the specified communication line can include a local area network (LAN: Local Area Network) such as a field network constructed within a facility (factory) where a specified machine driven by the motor M is installed. The LAN can be constructed wired, wirelessly, or include both. In addition, in the specified communication line, for example, a wide area network (WAN: Wide Area Network) outside the facility (factory) where a specified machine driven by the motor M is installed can be included. In the wide area network, for example, a mobile communication network with a base station at the end, a satellite communication network using communication satellites, the Internet, etc. can be included. In addition, in the specified communication line, for example, a short-range communication line based on a specified wireless communication standard such as Bluetooth (registered trademark) and WiFi can be included.

[0109] It should be noted that the function of the communication device 170 can be incorporated into the control device 140 (interface 144).

[0110] The cooling fan 180 (an example of a blowing unit) blows air to the subsequent cooling structure unit 190 (specifically, the heat sink unit 194), thereby promoting the heat dissipation of the cooling structure unit 190.

[0111] In the housing of the power conversion device 100, an outside air intake port (suction port) and an inside air discharge port (exhaust port) are provided. The cooling fan 180 is disposed upstream of the cooling structure portion 190 in the flow path of the air flowing from the intake port toward the exhaust port. In this case, the cooling fan 180 sucks in outside air from the intake port and sends it toward the cooling structure portion 190, so that the relatively low-temperature outside air reaches the cooling structure portion 190. Through heat exchange with the cooling structure portion 190, the heated air is discharged from the exhaust port. In addition, the cooling fan 180 may be disposed downstream of the cooling structure portion 190 in the flow path of the air flowing from the intake port toward the exhaust port. In this case, the cooling fan 180 sucks out the air around the cooling structure portion 190, and by creating a flow of air from the upstream intake port toward the cooling structure portion 190, the relatively low-temperature outside air reaches the cooling structure portion 190.

[0112] The arithmetic unit 200 (an example of a second external device) is provided outside the power conversion device 100 and is used to perform various arithmetic processes.

[0113] The arithmetic unit 200 can be communicably connected to the power conversion device 100 through a prescribed communication line, for example, and perform arithmetic processes related to the control of the power conversion device 100 according to instructions from the control device 140. Specifically, the arithmetic unit 200 can perform part or all of the arithmetic processes related to the determination of cooling abnormality described later according to instructions from the control device 140.

[0114] The arithmetic unit 200 can be, for example, a PLC (Programmable Logic Controller) or an edge controller for controlling a prescribed machine electrically driven by the motor M. In addition, the arithmetic unit 200 can be, for example, a computer terminal.

[0115] In addition, the arithmetic unit 200 can be, for example, a server device. The server device can be a cloud server provided outside the facility (factory) where the prescribed machine electrically driven by the motor M is installed. In addition, the server device can be, for example, an edge server provided inside the facility (factory) where the prescribed machine electrically driven by the motor M is installed or in a communication facility (such as a base station, shelter) near the facility.

[0116] The terminal device 300 (an example of a first external device) is provided outside the power conversion device 100 and is used by the user of the power conversion device 100 (cooling abnormality determination system 1). The terminal device 300 provides various information to the user through the display unit 310, for example, or receives various inputs from the user and sends them to the power conversion device 100.

[0117] The terminal device 300 may include a stationary terminal device such as a desktop computer terminal. Additionally, the terminal device 300 may include a portable (portable) terminal device (portable terminal) such as a smart phone, a tablet terminal, a laptop computer terminal, etc.

[0118] [Cooling Structure of Power Conversion Device]

[0119] Next, with reference to Figure 3 , the cooling structure portion 190 of the power conversion device 100 will be described.

[0120] Figure 3 It is a schematic diagram showing an example of the cooling structure portion 190 of the power conversion device 100.

[0121] The cooling structure portion 190 corresponds to, for example, a radiator, and includes a heat sink base 192 and a heat sink portion 194.

[0122] The heat sink base 192 has a flat plate shape with a predetermined thickness. On one surface (the lower surface in the figure) of the flat plate shape of the heat sink base 192, the heat sink portion 194 is provided, and on the other surface (the upper surface in the figure), the circuit boards 110A and 130A corresponding to the rectifier circuit 110 and the inverter circuit 130 are placed respectively.

[0123] The heat sink base 192 is made of a component with relatively high thermal conductivity. Thereby, the heat energy generated by the losses during energization of the semiconductor diode SD and the semiconductor switch SW can more easily flow to the heat sink base 192. The heat sink base 192 can be made of a metal such as aluminum, iron, copper, etc. The same applies to the heat sink portion 194 hereinafter.

[0124] As described above, the heat sink portion 194 is provided on one surface of the flat plate shape of the heat sink base 192. The heat sink portion 194 includes a plurality of heat sinks 194A provided so as to protrude in a direction (the negative Z-axis direction in the figure) away from the surface of the heat sink base 192.

[0125] The plurality of heat sinks 194A each have a very thin flat plate shape, and are arranged at substantially equal intervals in a predetermined direction (the X-axis direction in the figure) on one surface of the heat sink base 192.

[0126] The plurality of heat sinks 194A are each formed of a component having relatively high thermal conductivity. Thus, the heat energy generated by the losses when the semiconductor diode SD and the semiconductor switch SW are energized can easily flow from the heat sink base 192 to the plurality of heat sinks 194A. In addition, the plurality of heat sinks 194A have a relatively large surface area. Thus, the area of contact between the plurality of heat sinks 194A and the air is relatively large, and the heat energy can easily be dissipated to the surrounding air. Therefore, the heat energy generated by the losses when the semiconductor diode SD and the semiconductor switch SW are energized can easily be dissipated to the air, thereby improving the cooling performance of the power conversion device 100.

[0127] In addition, under the action of the cooling fan 180, the cooling air CA flows in a direction (Y-axis direction in the figure) perpendicular to the direction (X-axis direction) in which the plurality of heat sinks 194A are arranged. Thus, the cooling air CA passes between the plurality of heat sinks 194A, and the temperature of the air around the plurality of heat sinks 194A is maintained at a relatively low level. Therefore, the temperature difference between the heat sink 194A and the surrounding air becomes relatively large, and the heat energy can easily be dissipated to the surrounding air. Therefore, the heat energy generated by the losses when the semiconductor diode SD and the semiconductor switch SW are energized can easily be dissipated to the air, further improving the cooling performance of the power conversion device 100, and thus ensuring the cooling performance required by the power conversion device 100.

[0128] On the other hand, depending on the environment in which the power conversion device 100 is installed, there may be a situation where foreign matter clogs between the plurality of heat sinks 194A. In addition, depending on the size of the foreign matter, there is also a possibility that the foreign matter clogs the air inlet of the housing of the power conversion device 100. For example, in a textile factory, not only dust but also cotton may be contained in the air, and there is a possibility that cotton or the like clogs between the plurality of heat sinks 194A and the air inlet of the housing of the power conversion device 100. Then, there is a possibility that the cooling air CA cannot reach the heat sink 194A corresponding to the clogged portion by foreign matter, or the amount of outside air inhaled from the air inlet becomes smaller and the temperature of the air supplied to the heat sink portion 194 becomes higher. Therefore, the cooling performance of the semiconductor diode SD and the semiconductor switch SW based on the cooling structure portion 190 deteriorates, and as a result, an abnormality related to the cooling performance of the power conversion device 100 (semiconductor diode SD and semiconductor switch SW) based on the cooling structure portion 190 (hereinafter referred to as "cooling abnormality") occurs. And depending on the degree of the cooling abnormality, it becomes necessary to forcibly stop the power conversion device 100, and there is a possibility of affecting the mechanical operation of the factory where the specified machine electrically driven by the motor M is installed.

[0129] It should be noted that the cooling structure portion 190 only needs to be able to promote the dissipation of heat energy generated due to the loss during the energization of the semiconductor diode SD and the semiconductor switch SW to the surrounding air, and can be in any form. For example, there can be one heat sink 194A instead of multiple. In addition, on the heat sink base 192, one or more rod-shaped or needle-shaped protrusions made of components with relatively high thermal conductivity can be provided instead of the heat sink 194A.

[0130] [An example of the operation related to the determination of the cooling abnormality of the power conversion device]

[0131] Next, with reference to Figures 4 - 9 , an example of the operation related to the determination of the cooling abnormality of the power conversion device 100 will be described.

[0132] In this example, the control device 140 diagnoses a cooling abnormality (hereinafter, for convenience, referred to as "blockage abnormality") caused by the blockage of foreign matter between the heat sink portions 194 (multiple heat sinks 194A) and the air intake port of the housing of the power conversion device 100. The function of the control device 140 for diagnosing the blockage abnormality of the heat sink portion 194, etc. (hereinafter, referred to as "heat sink blockage diagnosis function") can be configured to be able to switch between an effective state (ON state) and an ineffective state (OFF state) according to the input received from the outside. For example, the user can switch the heat sink blockage diagnosis function between the ON state and the OFF state through a specified input portion provided on a specified machine electrically driven by the power conversion device 100 and the motor M. In addition, for example, the user can switch the heat sink blockage diagnosis function between the ON state and the OFF state through a specified input to the terminal device 300. In this case, a signal corresponding to the content of the input in the terminal device 300 is sent to the power conversion device 100 through a specified communication line and enters the control device 140 through the communication device 170. Thus, the control device 140 can switch the ON state and the OFF state of the heat sink blockage diagnosis function according to the input from the user.

[0133] Specifically, the control device 140 makes a determination related to the blockage abnormality of the heat sink portion 194 based on the temperature difference Y between the heat sink temperature Tf and the internal air temperature Ta. This is because if foreign matter blocks the heat sink portion 194 and the air intake port of the power conversion device 100, it is difficult for the wind to reach the heat sink 194A. As a result, the dissipation of heat energy from the heat sink 194A to the air becomes insufficient, and the temperature difference Y becomes relatively large (increases).

[0134] [Control processing related to the determination of cooling abnormality]

[0135] Figures 4 - 8FIG. 0 is a diagram showing an example of control processing related to determination of cooling abnormality based on control device 140. Specifically, Figure 4 FIG. 2 is a flowchart schematically showing an example of data acquisition processing related to determination of cooling abnormality based on control device 140. Figure 5 FIG. 3 is a flowchart schematically showing an example of end processing related to determination of cooling abnormality based on control device 140. Figure 6 FIG. 4 is a flowchart schematically showing an example of start processing related to determination of cooling abnormality based on control device 140. Figure 7 FIG. 5 is a flowchart schematically showing an example of determination processing of cooling abnormality based on control device 140. Figure 8 FIG. 6 is a flowchart schematically showing an example of determination processing of mitigation of cooling abnormality based on control device 140.

[0136] First, Figure 4 the flowchart of FIG. 2 is repeatedly executed in each predetermined control cycle during the operation of the power conversion device 100, that is, between the start of operation (specifically, power-on of control device 140) and the stop of operation (specifically, power-off of control device 140). Hereinafter, the same applies to the flowchart of FIG. 3 described later. Figure 12 The same applies to the flowchart of FIG. 3 described later.

[0137] As shown in Figure 4 FIG. 2, at step S102, control device 140 (CPU 141) determines whether the heat sink clogging diagnosis function is in the ON state. For CPU 141, when the heat sink clogging diagnosis function is in the ON state, the process proceeds to step S104, and when it is in the OFF state, the processing of this flowchart is ended.

[0138] It should be noted that the heat sink clogging diagnosis function may be fixed to a state where it is always effective. In this case, the processing of step S102 is omitted. Hereinafter, the same applies to step S702 of FIG. 3 described later. Figure 12 The same applies to step S702 of FIG. 3 described later.

[0139] At step S104, CPU 141 calculates the temperature difference Y (= Tf - Ta) between the heat sink temperature Tf and the internal air temperature Ta as an index for determining the presence or absence of clogging abnormality in the heat sink unit 194.

[0140] CPU 141 can calculate the temperature difference Y, for example, by the difference between the measured value of the heat sink temperature Tf based on the heat sink temperature sensor and the measured value of the internal air temperature Ta based on the internal air temperature sensor. Hereinafter, the temperature difference Y between the measured value of the heat sink temperature Tf based on the heat sink temperature sensor and the measured value of the internal air temperature Ta based on the internal air temperature sensor may sometimes be referred to as the "measured value of temperature difference Y".

[0141] In addition, the CPU 141 can correct the measured value of the temperature difference Y to the value of the temperature difference Y when the power conversion device 100 is in a specified load state (hereinafter referred to as the "reference load state") that serves as a reference. Thereby, the influence caused by the load state of the power conversion device 100 can be removed from the temperature difference Y to a certain extent, which is used as a determination index related to the blockage abnormality of the heat sink unit 194. This is because the heat sink temperature Tf changes due to the load state of the power conversion device 100, that is, the heat generation state generated by the losses of the semiconductor diode SD and the semiconductor switch SW, the ambient temperature, etc.

[0142] For example, the CPU 141 can correct the measured value of the temperature difference Y based on the estimated value of the junction temperature Tj to obtain the corrected value of the temperature difference Y in the reference load state of the power conversion device 100. This is because it is known that the junction temperature Tj does not change due to the influence of the air volume flowing into the heat sink unit 194, etc., but changes due to the load state of the power conversion device 100. Specifically, the CPU 141 can, for example, estimate (calculate) the losses of the power devices (semiconductor diode SD, semiconductor switch SW), and based on the estimated losses, obtain (calculate) the estimated value of the junction temperature Tj. And the CPU 141 can use a conversion formula, a conversion graph, etc. for obtaining the corrected value of the temperature difference Y to obtain the corrected value of the temperature difference Y from the measured value of the temperature difference Y and the estimated value of the junction temperature Tj.

[0143] In addition, for example, the CPU 141 can correct the measured value of the temperature difference Y based on the measured value of the load current IL of the load current sensor to obtain the corrected value of the temperature difference Y in the reference load state of the power conversion device 100. This is because the magnitude of the load current IL changes according to the load state of the power conversion device 100. Specifically, the CPU 141 can calculate the load state (load factor) of the power conversion device 100 based on the measured value of the load current IL by using a conversion formula and a conversion graph. And the CPU 141 can use a conversion formula, a conversion graph, etc. for obtaining the corrected value of the temperature difference Y to obtain the corrected value of the temperature difference Y from the measured value of the temperature difference Y and the calculated value of the load state of the power conversion device 100. In addition, the CPU 141 can convert the measured value of the load current IL into an index value in the unit of temperature for modifying the temperature difference Y, and use this index value to obtain the corrected value of the temperature difference Y.

[0144] It should be noted that the above conversion formula and conversion graph are determined in advance through experiments, simulations, etc. related to the power conversion device 100, for example.

[0145] After the CPU 141 finishes the processing of step S104, it proceeds to step S106.

[0146] In step S106, the CPU 141 determines whether the temperature difference Y calculated in step S104 exceeds a reference value Yth1. As a lower limit value capable of determining that clogging of the heat sink portion 194 has occurred, the reference value Yth1 (an example of a first reference value) can be determined in advance by experiments, simulations, etc. Further, the reference value Yth1 can be determined in advance based on at least one of a logical method and an approximation method, based on the temperature difference Y when the cooling performance of the cooling structure portion 190 is in a specified normal state and the temperature difference Y when the cooling fan 180 stops. Further, the reference value Yth1 is set to a value that is somewhat lower than a reference value Yth2 (an example of a second reference value) corresponding to the temperature difference Y when the power conversion device 100 is forced to stop due to a cooling abnormality of the power conversion device 100. When the temperature difference Y exceeds the reference value Yth1, the CPU 141 proceeds to step S108, and when it does not exceed the reference value Yth1, the processing of this flowchart ends.

[0147] In step S108, the CPU 141 determines whether the temperature difference Y calculated in step S104 exceeds a maximum temperature difference Ymax. The maximum temperature difference Ymax corresponds to the maximum value of the temperature difference Y in the ring buffer RB recorded in a specified storage area of the EEPROM 143B in advance, and is stored in the RAM 142B (see Figure 6 ). When the temperature difference Y calculated in step S104 exceeds the maximum temperature difference Ymax, the CPU 141 proceeds to step S110, and when it does not exceed the maximum temperature difference Ymax, the processing of this flowchart ends.

[0148] In step S110, the CPU 141 sets the maximum temperature difference Ymax to the temperature difference Y calculated in the current step S104. Thereby, the CPU 141 can use the temperature difference Y of this flowchart as the maximum temperature difference Ymax after the next flowchart.

[0149] After the CPU 141 finishes the processing of step S110, it proceeds to step S112.

[0150] In step S112, the CPU 141 stores the elapsed working time OT, and the current heat sink temperature Tf, internal air temperature Ta, and temperature difference Y in the RAM 142B. The working time OT represents the working time of the power conversion device 100 since the last reset. As will be described later, the working time OT is reset (cleared) when a temperature difference Y exceeding the past maximum temperature difference Ymax is recorded in the ring buffer RB (see Figure 5), so it is equivalent to the operating time of the power conversion device 100 after obtaining the previous maximum temperature difference Ymax. For example, the CPU 141 can read the operating time OT at the end of the previous operation from the EEPROM 143B, and accumulate the operating time since the current start based on the clock counter on the operating time OT at the end of the previous operation, thereby calculating the operating time OT. The operating time OT can include the entire period from the start to the stop of the power conversion device 100. Additionally, the operating time OT can also be the time that only measures the period during which the semiconductor diode SD and the semiconductor switch SW are energized in the entire period from the start to the stop of the power conversion device 100.

[0151] After the CPU 141 finishes the processing of step S112, it proceeds to step S114.

[0152] It should be noted that during the operation of the power conversion device 100, there may be a situation where the maximum temperature difference Ymax is updated multiple times. In this case, when the operation of the power conversion device 100 stops, only the data corresponding to the latest temperature difference Y that updates the maximum temperature difference Ymax is retained in the RAM 142B, and other data is not retained. Therefore, when the operation of the power conversion device 100 stops, the data of the temperature difference Y retained in the RAM 142B is data that is larger than the maximum temperature difference Ymax until the previous operation stop and corresponds to the maximum value of the temperature difference Y during the current operation.

[0153] Through step S114, the CPU 141 sets the new data flag F1 (F1 = SET) in the RAM 142A. Thereby, the CPU 141 can subsequently recognize that there is data of the temperature difference Y in the RAM 142B that is larger than both the reference value Yth1 and the maximum temperature difference Ymax (refer to step S204 described later). Figure 5 of step S204).

[0154] After the CPU 141 finishes the processing of step S114, it ends the processing of this flowchart.

[0155] It should be noted that the order of the processing of steps S112 and S114 can be reversed, and it can be in any order.

[0156] Thus, in this example, for the control device 140, during the operation of the power conversion device 100, if the temperature difference Y between the heat sink temperature Tf and the internal air temperature Ta exceeds both the reference value Yth1 and the maximum value of the past temperature difference Y (the maximum temperature difference Ymax), the temperature difference Y can be stored in the RAM 142B. In addition, the control device 140 can store the operating time OT corresponding to the operating time of the power conversion device 100 from when the temperature difference Y equivalent to the previous maximum temperature difference Ymax was obtained until the current temperature difference Y (i.e., the new maximum temperature difference Ymax) in the RAM 142B.

[0157] Next, Figure 5 The flowchart of Figure 5 is repeatedly executed at each prescribed control cycle during the operation of the power conversion device 100.

[0158] As Figure 5 shown, through step S202, the CPU 141 determines whether the power supply of the power conversion device 100 (control device 140) is detected as OFF. When the CPU 141 detects that the power supply of the power conversion device 100 is OFF, it proceeds to step S204. When the power supply OFF is not detected, the processing of the current flowchart ends.

[0159] It should be noted that in this example, in the ring buffer RB, there are buffer memories B (buffer memories B(1) to B(RPmax)) corresponding to an integer of 2 or more, i.e., the prescribed value RPmax. In addition, the ring buffer pointer RP indicates the recording position of data in the multiple (prescribed value RPmax) buffer memories B of the ring buffer RB, and the initial value is set to 1.

[0160] Through step S204, the CPU 141 determines whether a new data flag F1 is set in the RAM 142A. When the CPU 141 determines that the new data flag F1 is set in the RAM 142A, it proceeds to step S206. When the new data flag F1 is not set, the processing of the current flowchart ends.

[0161] Through step S206, the operating time OT stored in the RAM 142B, as well as the data of the temperature difference Y, the heat sink temperature Tf, and the internal air temperature Ta, are recorded in the ring buffer RB of the EEPROM 143B. Specifically, the above data are recorded in B(RP) corresponding to the current value of the ring buffer pointer RP among the prescribed value RPmax of buffer memories B between buffer memory B(1) and buffer memory B(RPmax) of the ring buffer RB.

[0162] After the CPU 141 completes the processing of step S206, it proceeds to step S208.

[0163] Through step S208, the CPU 141 clears (resets) the working time OT. Thus, starting from the recording of the current temperature difference Y, the timing of the working time OT begins from the next startup (power ON) of the power conversion device 100.

[0164] After the CPU 141 finishes the processing of step S208, it proceeds to step S210.

[0165] Through step S210, the CPU 141 advances the ring buffer pointer RP set in the EEPROM 143B by one pointer. Specifically, when the ring buffer pointer RP is smaller than the specified value RPmax, the ring buffer pointer RP is incremented by one pointer (RP = RP + 1). On the other hand, when the ring buffer pointer RP is the specified value RPmax, the ring buffer pointer RP is returned to "1" (RP = 1). Thus, the CPU 141 can record data in the buffer memory B at the next position of the buffer memory B in the ring buffer RB where the current data is recorded during the next data recording.

[0166] After the CPU 141 finishes the processing of step S210, it proceeds to step S212.

[0167] Through step S212, the CPU 141 sets the ring buffer flag F2 in the EEPROM 143B (F2 = SET). Thus, the CPU 141 can identify that data is recorded in the ring buffer RB by referring to the ring buffer flag F2 of the EEPROM 143B.

[0168] After the CPU 141 finishes the processing of step S212, it proceeds to step S214.

[0169] Through step S214, the CPU 141 clears the new data flag F1 in the RAM 142A.

[0170] After the CPU 141 finishes the processing of step S214, it ends the processing of the current flowchart.

[0171] It should be noted that the order of the processing of steps S208 to S214 can be appropriately changed to any order.

[0172] In this way, in this example, the CPU 141 can record the temperature difference Y, which is larger than the maximum temperature difference Ymax until the previous time and is the maximum temperature difference during the current operation, in the non-volatile ring buffer RB at the end of the operation of the power conversion device 100. At the same time, the CPU 141 can record the working time OT corresponding to the working time of the power conversion device 100 from the start of recording the previous maximum temperature difference Ymax until obtaining the temperature difference Y of the current recording object in the non-volatile ring buffer RB.

[0173] Next, Figure 6 It is executed when starting the operation of, for example, the power conversion device 100 (specifically, when the power supply of the control device 140 is turned on).

[0174] As Figure 6 shown, in step S302, the CPU 141 determines whether data is recorded in the ring buffer, that is, whether the ring buffer flag F2 is set in the EEPROM 143B. When the ring buffer flag F2 is set, the CPU 141 proceeds to step S304; when the ring buffer flag F2 is not set, the processing of this flowchart ends.

[0175] In step S304, the CPU 141 reads the ring buffer pointer RP from the EEPROM 143B.

[0176] After completing the processing of step S304, the CPU 141 proceeds to step S306.

[0177] In step S306, the CPU 141 reads the latest heat sink temperature Tf, internal air temperature Ta, and temperature difference Y from the buffer memory B(RP) corresponding to the value of the ring buffer pointer RP in the ring buffer RB, and stores them in the RAM 142B.

[0178] After completing the processing of step S306, the CPU 141 proceeds to step S308.

[0179] In step S308, the CPU 141 sets the read latest temperature difference Y as the maximum temperature difference Ymax in the RAM 142B.

[0180] After completing the processing of step S308, the CPU 141 ends the processing of this flowchart.

[0181] Thus, in this example, the CPU 141 obtains the latest data of the temperature difference Y stored in the ring buffer RB and sets it as the maximum temperature difference Ymax. Therefore, the CPU 141 can judge the increase in the temperature difference Y based on the latest temperature difference Y recorded until the last operation stop, that is, the maximum temperature difference Y until the last operation stop (refer to step S108 in Figure 4 ).

[0182] Next, Figure 7 the flowchart of Figure 7 is executed at a specified time. For example, the flowchart of Figure 7The flowchart can be executed during the operation of the power conversion device 100 when data such as the temperature difference Y in the RAM 142B is updated (refer to Figure 4 step S112). Additionally, for example, Figure 7 the flowchart can be configured to be manually executable based on an input from the user. In this case, an input from the user can be received through, for example, an input unit provided in a prescribed machine electrically driven by the power conversion device 100 and the motor M, or an input from the user can be received from the terminal device 300 through a prescribed communication line.

[0183] As Figure 7 shown, the CPU 141 determines whether data is recorded in the ring buffer RB, that is, whether the ring buffer flag F2 is set in the RAM 142B. When the ring buffer flag F2 is set, the CPU 141 proceeds to step S404. When the ring buffer flag F2 is not set, the processing of the current flowchart ends.

[0184] Through step S404, the CPU 141 determines whether the heat sink temperature Tf stored in the RAM 142B is greater than the reference value Tf_th1. For example, through experiments and simulations, the reference value Tf_th1 is determined in advance as the lower limit value capable of judging the occurrence of a foreign object blockage in the heat sink unit 194. Additionally, the reference value Tf_th1 is set to be somewhat lower than the reference value Tf_th2 corresponding to the heat sink temperature Tf when the heat sink temperature Tf becomes very high and the power conversion device 100 is forcibly stopped as the heating state of the heat sink unit 194. Thereby, it is possible to judge the cooling abnormality of the power conversion device 100 before the power conversion device 100 is forcibly stopped. When the heat sink temperature Tf is greater than the reference value Tf_th1, the CPU 141 proceeds to step S406. When it is below the reference value Tf_th1, the CPU 141 proceeds to step S408.

[0185] Through step S406, the CPU 141 reports an alarm (hereinafter referred to as "heat sink blockage alarm") indicating the possibility of blockage in the heat sink unit 194 to the user.

[0186] The heat sink blockage alarm can be reported to the user through the display device 160, for example. In the display device 160, only the fact of the report of the heat sink blockage alarm can be displayed. Additionally, in the display device 160, in addition to the fact of the report of the heat sink blockage alarm, data on the operating state (operation state) of the power conversion device 100, including the heat sink temperature Tf, the internal air temperature Ta, and the temperature difference Y, and data representing the history thereof can be displayed as numerical values. The data representing the history can be, for example, data representing the change in the temperature difference Y.

[0187] In addition, a heat sink clogging alarm can be reported to the user by the terminal device 300, for example. In this case, a signal equivalent to the heat sink clogging alarm output from the control device 140 (hereinafter referred to as the "alarm signal") is sent from the communication device 170 to the terminal device 300. When the terminal device 300 receives the alarm signal, it notifies the user of the heat sink clogging alarm through the display unit 310. In the terminal device 300 (display unit 310), similar to the case of reporting the heat sink clogging alarm through the display device 160, only the fact can be displayed, or data related to the operating state of the power conversion device 100 can be displayed as a numerical value together.

[0188] After the CPU 141 finishes the processing of step S406, it proceeds to step S420.

[0189] On the other hand, through step S408, the CPU 141 determines whether the internal air temperature Ta stored in the RAM 142B is greater than the reference value Ta_th1. For example, through experiments and simulations, the reference value Ta_th1 is specified in advance as the lower limit value that can determine that the internal air temperature of the power conversion device 100 has deviated from the normal range. When the internal air temperature Ta is greater than the reference value Ta_th1, the CPU 141 proceeds to step S410, and when it is less than or equal to the reference value Ta_th1, it proceeds to step S412.

[0190] Through step S410, the CPU 141 reports both an alarm indicating abnormal internal air temperature (hereinafter referred to as the "internal air abnormality alarm") and a heat sink clogging alarm to the user.

[0191] Similar to the case of the heat sink clogging alarm, the internal air abnormality alarm can be reported through the display device 160 or through the terminal device 300 (display unit 310). In addition, in the display device 160 and the terminal device 300 (display unit 310), similar to the case of the heat sink clogging alarm, only the fact that the internal air alarm has been reported can be displayed, or data related to the operating state of the power conversion device 100 can be displayed as a numerical value together.

[0192] After the CPU 141 finishes the processing of step S410, it proceeds to step S420.

[0193] On the other hand, through step S412, the CPU 141 determines whether the number of data recorded in the ring buffer RB, that is, the number of buffer memories B(1) to B(RPmax) in the buffer memory of the ring buffer RB that record data, is equal to or more than a specified number (for example, four). When the number of data recorded in the ring buffer RB is equal to or more than the specified number, the CPU 141 proceeds to step S414; when it is less than the specified number, the processing of this flowchart ends. This is because by determining cooling anomalies using as much data on the temperature difference Y as possible, the possibility of misjudging clogging anomalies in the heat sink unit 194 can be suppressed.

[0194] Through step S414, the CPU 141 approximately predicts the future temporal change of the temperature difference Y based on the temperature difference Y and the operating time OT data recorded in the ring buffer RB that are equal to or more than the specified number. Specifically, the CPU 141 predicts the required time TMest until the temperature difference Y reaches the reference value Yth2 at which the power conversion device 100 is forced to stop.

[0195] For example, the CPU 141 can predict the future temporal change of the temperature difference Y through linear approximation based on the history of the temperature difference Y and the operating time OT, thereby predicting the required time TMest. Additionally, for example, the CPU 141 can use the method of multivariate analysis based on other data related to the operating state (operation state) of the power conversion device 100, such as the temperature difference Y, the heat sink temperature Tf, the internal air temperature Ta, and the operating time OT, to predict the future temporal change of the temperature difference Y, thereby predicting the required time TMest. In this case, at the time when the temperature difference Y and the like are stored in the RAM 142B (refer to Figure 4 step S112), the other data is also stored in the RAM 142B, and at the time when the operation of the power conversion device 100 stops (refer to Figure 5 step S206), it is recorded in the ring buffer RB. The other data can include, for example, data such as the speed command value of the motor M, the frequency command value of the output power, the output voltage command value, the output current detection value, the operation history information, the measurement values of other temperature sensors, and the fault history information.

[0196] After the CPU 141 completes the processing of step S414, it proceeds to step S416.

[0197] In step S416, the CPU 141 determines whether the required time TMest is shorter (smaller) than the reference time TMth (an example of the first reference time). When the required time TMest is shorter than the reference time TMth, the CPU 141 proceeds to step S418. When the required time TMest is equal to or longer than the reference time TMth, the processing of this flowchart is terminated.

[0198] In step S418, the CPU 141 reports a heat sink clogging alarm to the user.

[0199] As described above, the heat sink clogging alarm can be reported to the user via the display device 160 or via the terminal device 300. In addition, as described above, in the display device 160, the terminal device 300 (display unit 310), etc., only the fact of the heat sink clogging alarm can be displayed, or data related to the operating state of the power conversion device 100 can be displayed as numerical values together.

[0200] After completing the processing of step S418, the CPU 141 proceeds to step S420.

[0201] In step S420, the CPU 141 determines whether the operating time TMfan of the cooling fan 180 is equal to or longer than the reference value TMfan_th. The operating time TMfan of the cooling fan 180 corresponds to the cumulative operating time since the cooling fan 180 was new. The operating time TMfan can be obtained by cumulative counting based on the clock counter of the CPU 141 in its operating time since the power conversion device 100 was shipped from the factory. In addition, resetting can be performed when the cooling fan 180 is replaced. The reference value TMfan_th is predefined as the so-called lifetime or warranty period of the cooling fan 180. When the operating time TMfan of the cooling fan 180 is equal to or longer than the reference value TMfan_th, the CPU 141 proceeds to step S422. When the operating time TMfan of the cooling fan 180 is shorter (smaller) than the reference value TMfan_th, the processing of this flowchart is terminated.

[0202] In step S422, the CPU 141 reports an alarm indicating the possibility of an abnormality in the cooling fan (hereinafter referred to as "fan abnormality alarm") to the user.

[0203] The fan abnormality alarm can be reported to the user through the display device 160 in the same way as the heat sink blockage alarm, etc., or can also be reported to the user through the terminal device 300. In addition, in the display device 160, the terminal device 300 (display unit 310), etc., only the fact of the fan abnormality alarm can be displayed. In addition, in the display device 160, the terminal device 300 (display unit 310), data related to the operating state of the power conversion device 100 associated with the fan abnormality alarm (for example, the value of the operating time TMfan equivalent to the cumulative operating time of the cooling fan 180, etc.) can be displayed together.

[0204] After the CPU 141 finishes the processing of step S422, it ends the processing of the present flowchart.

[0205] Thus, in this example, the control device 140 determines the presence or absence of a blockage abnormality in the heat sink unit 194 based on the increasing tendency of the temperature difference Y. Specifically, the control device 140 predicts the temporal change of the temperature difference Y based on the historical record of the past temperature difference Y recorded in the ring buffer RB, thereby obtaining the required time TMest until the temperature difference Y reaches the reference value Yth2. And when the control device 140 determines that the required time TMest is shorter than the reference time TMth, that is, when the temperature difference Y exceeds the reference value Yth2 and the moment when the power conversion device 100 is forced to stop is approaching, it reports a heat sink blockage alarm to the user. Thereby, the control device 140 can urge the user to clean the heat sink unit 194, etc. at a stage before the temperature difference Y exceeds the reference value Yth2 and the power conversion device 100 is forced to stop.

[0206] In addition, since the blockage of the heat sink unit 194, etc. progresses gradually, there is a possibility that it becomes difficult to adjust the operation period of a specified machine driven by the motor M and the maintenance period for cleaning the heat sink unit 194, etc.

[0207] In contrast, in this example, by appropriately adjusting the required time TMest, the control device 140 can report a heat sink blockage alarm to the user at a stage before the blockage abnormality progresses to the procedure of forcing the power conversion device 100 to stop. Therefore, the user can receive the report of the heat sink blockage alarm and thus adjust the operation period of the specified machine driven by the motor M electrically and the maintenance period.

[0208] In addition, in this example, when the heat sink temperature Tf is greater than a reference value Tf_th1 that is lower than a reference value Tf_th2 corresponding to the heat sink temperature Tf at which the power conversion device 100 is forced to stop, the CPU 141 reports a heat sink clogging alarm to the user. Thereby, the control device 140 can urge the user to clean the heat sink unit 194 or the like at a stage before the heat sink temperature Tf exceeds the reference value Tf_th2 and the power conversion device 100 is forced to stop.

[0209] In addition, in this example, when the internal air temperature Ta is greater than a reference value Ta_th1, the CPU 141 reports an internal air abnormality alarm and a heat sink clogging alarm to the user. Thereby, in a situation where the internal air temperature deviates from the normal range and becomes high, the user can be urged to perform various maintenance operations for suppressing the rise of the internal air temperature, including cleaning for removing the clogging of the heat sink unit 194.

[0210] Next, Figure 8 The flowchart of Figure 8 is repeatedly executed for each predetermined control cycle during the operation of the power conversion device 100.

[0211] As Figure 8 shown, in step S502, the CPU 141 determines whether data is recorded in the ring buffer RB, that is, whether a ring buffer flag F2 is set in the RAM 142A. When the ring buffer flag F2 is set, the CPU 141 proceeds to step S504, and when the ring buffer flag F2 is not set, the processing of this flowchart is ended.

[0212] In step S504, the CPU 141 determines whether the operation time OT is equal to or greater than a reference time OTth (an example of a second reference time). When the operation time OT is equal to or greater than the reference time OTth, the CPU 141 proceeds to step S506, and when it is less than the reference time OTth, the processing of this flowchart is ended.

[0213] In step S506, the CPU 141 determines whether the ring buffer pointer RP is the start pointer RPtop. The start pointer RPtop corresponds to the number of the buffer memory B that stores the earliest data among the buffer memories B(1) to B(RPmax) of the ring buffer RB. The initial value of the start pointer RPtop is "1". If data is stored in all of the buffer memories B(1) to B(RPmax) and the latest data is stored in the buffer memory B(1), the start pointer RPtop moves to "2". And then, each time the latest data is stored, the start pointer RPtop moves forward by one position. When the ring buffer pointer RP is the start pointer RPtop, the CPU 141 proceeds to step S508, and when the start pointer is not RPtop, the CPU 141 proceeds to step S510.

[0214] In step S508, the CPU 141 clears the ring buffer pointer RP and the ring buffer flag F2 of the EEPROM 143B.

[0215] After the CPU 141 finishes the process of step S508, it proceeds to step S512.

[0216] On the other hand, in step S510, the CPU 141 returns the ring buffer pointer RP by one position. For example, when the ring buffer pointer RP is not 1, the value of the ring buffer pointer RP is decremented by one (RP = RP - 1). Additionally, for example, when the ring buffer pointer RP is "1", the ring buffer pointer RP is set to RPmax (RP = RPmax).

[0217] After the CPU 141 finishes the process of step S510, it proceeds to step S512.

[0218] In step S512, the CPU 141 clears the working time OT. Thus, the counting of the working time OT starts again from zero.

[0219] After the CPU 141 finishes the process of step S512, it ends the processing of the current flowchart.

[0220] In this way, in this example, when a certain amount of time (reference time OTth) has passed since the latest data was recorded in the ring buffer RB, the control device 140 returns the ring buffer pointer RP by one position, considering that there is no latest data. Thus, for example, after the latest data is acquired, when the heat sink unit 194 and the air inlet of the housing of the power conversion device 100 are cleaned, and the increasing tendency of the temperature difference Y is eliminated, the occurrence of misjudging a cooling abnormality using the latest data can be suppressed.

[0221] In addition, in this example, the control device 140 can retain data that is earlier than the latest data in the ring buffer RB. Thus, for example, in a situation where the heat sink unit 194 and the intake port of the housing of the power conversion device 100 are cleaned but the cleaning is insufficient and the increase in the temperature difference Y immediately starts, not only the newly recorded data but also the retained data can be used. Therefore, even when the increase in the temperature difference Y reappears after a simple cleaning temporarily eliminates the increase in the temperature difference Y, the control device 140 can determine the presence of a blockage abnormality in the heat sink unit 194 at an earlier stage.

[0222] In addition, in this example, after the control device 140 returns the ring buffer RB by one bit, it clears the working time OT. Thus, the control device 140 can keep the state of not recording new data each time the reference time OTth elapses after recording the latest data in the ring buffer RB and return the ring buffer pointer RP by one bit. And if the ring buffer pointer RP returns to the start pointer RPtop and no new data is recorded in this state and the reference time OTth elapses, the control device 140 can also regard the state as one where there is no data in the ring buffer RB. Therefore, for example, in a situation where the increase in the temperature difference Y is completely eliminated by cleaning the heat sink unit 194, the intake port of the housing of the power conversion device 100, etc., the control device 140 can suppress the situation of misjudging a cooling abnormality using earlier data.

[0223] <Specific example of the determination operation of cooling abnormality>

[0224] Figure 9 It is a diagram for explaining an example of the operation related to the determination of a cooling abnormality based on the control device 140. Specifically, Figure 9 It is a diagram showing the data Tf_N1, Tf_N2, Tf_N3, Tf_N4 of the heat sink temperature Tf and the data Y_N1, Y_N2, Y_N3, Y_N4 of the temperature difference Y recorded in the ring buffer RB by the control device 140 in chronological order. Figure 9 It includes a graph 910 showing the data Tf_N1, Tf_N2, Tf_N3, Tf_N4 of the heat sink temperature Tf in chronological order, and a graph 920 showing the data Y_N1, Y_N2, Y_N3, Y_N4 of the temperature difference Y in chronological order.

[0225] It should be noted that the data Tf_N1 and the data Y_N1, the data Tf_N2 and the data Y_N2, the data Tf_N3 and the data Y_N3, and the data Tf_N4 and the data Y_N4 are respectively the data recorded in the ring buffer RB at the same time. The same applies to the following Figure 11 cases.

[0226] As Figure 9 shown, when the temperature difference Y is below the reference value Yth1 (refer to the data Y_NX in the figure), the data is not recorded in the ring buffer RB. On the other hand, if the temperature difference Y exceeds the reference value Yth1, it is determined that there is a sign of clogging abnormality in the heat sink portion 194, and new data (in this example, data Y_N1, Tf_N1) is recorded in the ring buffer RB (refer to Figure 4 ). And each time the current temperature difference Y exceeds the maximum value of the recorded past temperature difference Y (maximum temperature difference Ymax), new data (in this example, data Tf_N2, Y_N2, etc.) is successively recorded in the ring buffer RB (refer to Figure 4 ). Thus, in the ring buffer RB, historical record data of the temperature difference Y indicating the increasing tendency of the temperature difference Y is accumulated.

[0227] In this example, at the moment after the data Y_N4, Tf_N4 are recorded, based on the data Y_N1, Y_N2, Y_N3, and Y_N4, the control device 140 predicts the time change of the temperature difference Y by linear approximation. Specifically, the control device 140 calculates the approximate straight line L1 of the time change, and calculates the required time TMest from the intersection of the approximate straight line L1 and the straight line corresponding to the reference value Yth2, and determines that the calculated required time TMest is shorter than the reference time TMth. Therefore, the control device 140 can report a heat sink clogging alarm, thereby urging the user to clean the clogging of the heat sink portion 194, etc.

[0228] In addition, before the stage of obtaining the data Y_N4, Tf_N4, there may be a case where the data of the heat sink temperature Tf (in this example, data Tf_N3a) exceeds the reference value Tf_th1. In this case, the control device 140 also reports a heat sink clogging alarm. Therefore, even when the rising tendency of the heat sink temperature Tf is more significant than the increasing tendency of the temperature difference Y, the control device 140 can appropriately make the user aware of the possibility of clogging abnormality in the heat sink portion 194, and urge the user to clean the clogging of the heat sink portion 194, etc.

[0229] In addition, before the data Y_N4 and Tf_N4 are acquired, there may be a situation where the heat sink unit 194 and the air inlet of the housing of the power conversion device 100 are cleaned. For example, if the cleaning is performed after the data Y_N2 and Tf_N2 are recorded, the increasing tendency of the temperature difference Y is eliminated, and even if the time elapses for more than the reference time OTth, the data Y_N3b cannot exceed the data Y_N2, so that new data is not recorded. In this case, the control device 140 returns the ring buffer pointer RP by one bit, and it is regarded that the latest data Y_N2 does not exist. Therefore, the control device 140 uses the latest data Y_N2 to suppress the situation where the increasing tendency of the temperature difference Y is misjudged. As a result, the misjudgment of the blockage abnormality of the heat sink unit 194 can be suppressed.

[0230] [Another example of the operation related to the determination of the cooling abnormality of the power conversion device]

[0231] Next, refer to Figure 10 , Figure 11 , and another example of the operation related to the determination of the cooling abnormality of the power conversion device 100 will be described.

[0232] The following will mainly describe the parts different from the above example, and sometimes the description of the same or corresponding content will be abbreviated or omitted.

[0233] <Control process related to the determination of cooling abnormality>

[0234] Figure 10 is a diagram showing another example of the control process related to the determination of cooling abnormality. Specifically, Figure 10 is a flowchart schematically showing another example of the data acquisition process related to the determination of cooling abnormality.

[0235] In this example, the end process related to the determination of cooling abnormality, the start process related to the determination of cooling abnormality, the cooling abnormality determination process, and the cooling abnormality mitigation determination process are the same as the above example ( Figures 5 - 8 ), so the description is omitted.

[0236] Figure 10 The flowchart of Figure 4 is the same as the above example (the same as the case of

[0237] For example, during the operation of the power conversion device 100, that is, between the start of operation (power ON of the control device 140) and the stop of operation (power OFF of the control device 140), it is repeatedly executed in each specified control cycle. Figure 10 As Figure 4 shows, the processes of steps S602 and S604 are the same as steps S102 and S104 of

[0238] After the CPU 141 finishes the processing of step S604, it proceeds to step S606.

[0239] In step S606, the CPU 141 determines whether there is data recorded in the ring buffer RB, that is, whether the ring buffer flag F2 is set in the RAM 142B. If the ring buffer flag F2 is not set, the CPU 141 proceeds to step S608; if the ring buffer flag F2 is set, the CPU 141 proceeds to step S610.

[0240] In step S608, the CPU 141 determines whether the temperature difference Y is greater than the reference value Yth0 (<Yth1) (an example of the third reference value) and the temperature difference Y is less than or equal to the reference value Yth1. If the temperature difference Y is greater than the reference value Yth0 and the temperature difference Y is less than or equal to the reference value Yth1, the CPU 141 proceeds to step S616; otherwise, the current flowchart ends.

[0241] On the other hand, the processing of steps S610 to S614 is the same as Figure 4 steps S106 to S110 of

[0242] After the CPU 141 finishes the processing of step S614, it proceeds to step S616.

[0243] The processing of steps S616 and S618 is the same as Figure 4 steps S112 and S114 of

[0244] After the CPU 141 finishes the processing of step S618, the processing of the current flowchart ends.

[0245] Thus, in this example, when there is no data recorded in the ring buffer RB, the control device 140 records the temperature difference Y, such as when the temperature difference Y is greater than the reference value Yth0 (<Yth1) and the temperature difference Y is less than or equal to the reference value Yth1, as the initial data in the ring buffer RB. On this basis, the control device 140 accumulatively records data including the temperature difference Y exceeding the reference value Yth1 in the ring buffer RB. Thereby, data on the situation where the temperature difference Y sharply exceeds the reference value Yth1 for some reason other than the blockage of the heat sink unit 194 is obtained, and the situation of misjudging the blockage abnormality of the heat sink unit 194 can be suppressed. This is because the progress of the blockage abnormality of the heat sink unit 194 is relatively gentle, and it is less likely to initially obtain data in the range exceeding the reference value Yth1 without obtaining data in the range where the temperature difference Y is greater than the reference value Yth0 and less than or equal to the reference value Yth1.

[0246] <Specific example of the cooling abnormality determination operation>

[0247] Figure 11 It is a diagram for explaining another example of the operation related to the determination of cooling abnormality based on the control device 140. Specifically, Figure 11 It is a diagram showing in chronological order the data Tf_N0, Tf_N1, Tf_N2, Tf_N3, Tf_N4 of the heat sink temperature Tf recorded in the ring buffer RB by the control device 140, and the data Y_N0, Y_N1, Y_N2, Y_N3, Y_N4 of the temperature difference Y. Figure 11 It includes a graph 1110 showing the data Tf_N0, Tf_N1, Tf_N2, Tf_N3, Tf_N4 of the heat sink temperature Tf in chronological order, and a graph 1120 showing the data Y_N0, Y_N1, Y_N2, Y_N3, Y_N4 of the temperature difference Y in chronological order.

[0248] Figure 11 Except for adding the data Tf_N0 and Y_N0, it is the same as the above-mentioned one example ( Figure 9 ). Hereinafter, the description will focus on the parts different from the above-mentioned one example ( Figure 9 ).

[0249] It should be noted that the data Tf_N0 and the data Y_N0 are the data recorded in the ring buffer RB at the same time.

[0250] As Figure 11 shown, in this example, different from the above-mentioned one example ( Figure 9 ), the data Y_N0 and Tf_N0 in the range where the temperature difference Y is larger than the reference value Yth0 and the temperature difference Y is equal to or less than the reference value Yth1 are initially recorded in the ring buffer RB. And then, the data Y_N1 and Tf_N1 where the temperature difference Y exceeds the reference value Yth1 are recorded in the ring buffer RB. Thus, for example, it is possible to prevent the situation where the temperature difference Y suddenly increases due to some reason different from the blockage abnormality of the heat sink unit 194 and the data where the temperature difference Y exceeds the reference value Yth1 is not recorded in the ring buffer RB. Therefore, it is possible to suppress the control device 140 from misjudging the blockage abnormality of the heat sink unit 194 using such data.

[0251] [Another example of the operation related to the determination of cooling abnormality of the power conversion device]

[0252] Next, with reference to Figure 12 , another example of the operation related to the determination of cooling abnormality of the power conversion device 100 will be described.

[0253] Hereinafter, the description will focus on the parts different from the above-mentioned one example etc., and sometimes the description of the same or corresponding content will be abbreviated or omitted.

[0254] Figure 12 This is a diagram showing another example of the control process related to the determination of cooling abnormalities. Specifically, Figure 12 This is a flowchart schematically showing another example of the determination process for cooling abnormalities.

[0255] In the above example and others, the control device 140 determines the presence or absence of a cooling abnormality in the power conversion device 100 based on the time variation of the increase in the temperature difference Y. However, the presence or absence of a cooling abnormality in the power conversion device 100 can be determined more simply based on the temperature difference Y. Specifically, the control device 140 can determine the presence of a cooling abnormality in the heat sink unit 194 when the temperature difference Y becomes relatively high (for example, when the temperature difference Y exceeds the reference value Yth1 or exceeds a specified reference value set between the reference value Yth1 and the reference value Yth2). The following is a specific description.

[0256] As Figure 12 shown, the processes of steps S702 and S704 are the same as those of steps S102 and S104 of Figure 4 and thus the description thereof is omitted.

[0257] After completing the process of step S704, the control device 140 proceeds to step S706.

[0258] In step S706, the CPU 141 determines whether the temperature difference Y calculated in step S104 exceeds the reference value Yth1. If the temperature difference Y exceeds the reference value Yth1, the CPU 141 determines that there is an abnormality in the cooling structure unit 190 (heat sink unit 194) and proceeds to step S708. If it does not exceed the reference value Yth1, the processing of this flowchart ends.

[0259] In step S708, the CPU 141 reports a heat sink blockage alarm to the user.

[0260] After completing the process of step S708, the control device 140 ends the processing of this flowchart.

[0261] It should be noted that in this example, the control process related to the determination of cooling abnormalities is concentrated in the Figure 12 flowchart, and data acquisition processes, end processes, and start processes related to the determination of cooling abnormalities in the above example and others are not set. Therefore, in this example, the EEPROM 143B and the ring buffer RB can be omitted.

[0262] Thus, in this example, the control device 140 can make only the temperature difference Y relatively high as a trigger point, thereby determining that there is a cooling abnormality in the cooling structure portion 190 (the heat sink portion 194). Therefore, the control device 140 can determine the cooling abnormality of the cooling structure portion 190 with a relatively simple configuration.

[0263] [Another Embodiment]

[0264] Next, another embodiment will be described.

[0265] The content of the above embodiment can be appropriately deformed and changed.

[0266] In addition, for example, in the above embodiment, the control device 140 can extract singular values from the data of the temperature difference Y recorded in the ring buffer RB. And the control device 140 can make a determination related to the cooling abnormality based on the data of the temperature difference Y other than the singular values in the data of the temperature difference Y recorded in the ring buffer RB. Thereby, the control device 140 can improve the accuracy of the determination related to the cooling abnormality, and thus can make a more appropriate determination related to the cooling abnormality. Specifically, when approximately predicting the time change of the temperature difference Y (required time TMest) (refer to Figure 7 step S414), the control device 140 can use only the data of the temperature difference Y other than the singular values. Thereby, the control device 140 can improve the prediction accuracy of the required time TMest.

[0267] In addition, for example, in the above embodiment ( Figure 8 ), if the time after the latest data is recorded in the ring buffer RB exceeds the reference time OTth, the ring buffer pointer RP returns one bit, but the B(RP) of the ring buffer RB can be deleted together.

[0268] In addition, for example, in the above embodiment, the power conversion device 100 (the control device 140) can manually delete all the data in the ring buffer RB according to the input received from the user. Thus, when the user cleans, for example, the heat sink portion 194 or the air inlet of the housing of the power conversion device 100, the user can delete the data in the ring buffer RB by himself / herself. In this case, the input from the user can be received through the input unit provided in a prescribed machine electrically driven by the power conversion device 100 and the motor M, or can be received through the terminal device 300 communicably connected to the power conversion device 100.

[0269] In addition, for example, in the above-described embodiment, the power conversion device 100 (control device 140) may be configured to automatically delete all the data in the ring buffer RB when the possibility of cooling abnormality is eliminated. For example, after the latest data is recorded in the ring buffer RB, the control device 140 may determine that the heat sink unit 194 has been cleaned and the possibility of cooling abnormality has been eliminated when the operating time OT has remained in a state where no new data is recorded for more than a specified threshold. The specified threshold may be determined in advance within a range equal to or higher than the reference time OTth. In addition, for example, the control device 140 may determine that the possibility of cooling abnormality has been eliminated when the temperature difference Y has continuously remained below the reference value Yth1 between the start (power ON) and stop (power OFF) of the current operation of the power conversion device 100. In this case, the control device 140 may delete all the data in the ring buffer RB when it determines that the possibility of cooling abnormality has been eliminated (i.e., when the operation of the power conversion device 100 stops), or at the start of the next operation.

[0270] In addition, for example, in the above-described embodiment, although the data including the temperature difference Y and the operating time OT, which are used in the determination of cooling abnormality, are recorded inside the power conversion device 100, they may also be recorded in an external device of the power conversion device 100. The external device may be, for example, an arithmetic device 200 or a terminal device 300 (both are examples of a third external device). In this case, the control device 140 sends the data related to the temperature difference Y and the data related to the operation mode of the power conversion device 100 to the external device and accumulates them in the external device. The data related to the operation mode of the power conversion device 100 includes, for example, the data indicating the start and stop times of the operation, the data related to the communication times of the semiconductor diode SD and the semiconductor switch SW, and the like. And the control device 140 may determine the presence or absence of cooling abnormality by the same method as above by downloading and using the accumulated data from the external device.

[0271] In addition, for example, in the above-described embodiment, a part or all of the functions of the control device 140 may be transferred to an external device of the power conversion device 100, such as an arithmetic device 200 or a terminal device 300 (both are examples of a cooling abnormality determination device).

[0272] [Function]

[0273] Next, the function of the power conversion device 100 (control device 140) of the present embodiment will be described.

[0274] In the present embodiment, the power conversion device 100 includes a power device, a cooling structure portion 190, a cooling fan 180, and a control device 140. Specifically, the power device includes a semiconductor diode SD and a semiconductor switch SW. In addition, the cooling structure portion 190 is provided for heat dissipation of the power device. In addition, the cooling fan 180 blows air toward the cooling structure portion 190. And the control device 140 makes a determination related to an abnormality in the cooling performance of the cooling structure portion 190 based on the temperature difference Y between the temperature of the cooling structure portion 190 (the heat sink portion 194) (the heat sink temperature Tf) and the temperature inside the power conversion device 100 (the housing) (the internal air temperature Ta).

[0275] Accordingly, the control device 140 focuses on the fact that the temperature difference Y becomes relatively large due to blockage of the heat sink portion 194 or the like, and thus can appropriately determine the presence or absence of a cooling abnormality in the cooling structure portion 190.

[0276] In addition, for example, as described in the above Patent Document 1, it is also possible to determine a cooling abnormality using the temperature itself of a specified portion of the power conversion device 100. However, since there is a possibility that the influence caused by the change in the load state of the power conversion device overlaps in the change in the measured temperature, there is a possibility that the accuracy of determining a cooling abnormality of the heat sink is reduced.

[0277] In contrast, in the present embodiment, the control device 140 does not use the temperature itself of a specified portion of the power conversion device 100, but uses the difference in temperature (temperature difference Y) between two portions inside the power conversion device 100, thereby suppressing the influence of the load state of the power conversion device 100 and enabling a more appropriate determination related to a cooling abnormality.

[0278] In addition, for example, as described in the above Patent Document 2, it is also possible to determine a cooling abnormality using, in addition to the temperature of the heat sink and the temperature inside the power conversion device, the load state of the power conversion device. In this case, considering the load state of the power conversion device, an improvement in determination accuracy can be expected. However, in the respective methods of individually using the temperature of the heat sink and the temperature inside the power conversion device, as in Patent Document 2, it is necessary to assume a heating abnormality such that the power conversion device is forcibly stopped. As described above, this is because the progress of a blockage abnormality of the heat sink or the like is relatively slow, and thus it is difficult to capture the tendency of its cooling abnormality even when considering the influence of the load state of the power conversion device by individually using the temperature of the heat sink and the temperature inside the power conversion device.

[0279] In contrast, in the present embodiment, the control device 140 can more appropriately (earlier) make a determination related to cooling abnormality before reaching the state necessary to force the power conversion device 100 to stop by, for example, detecting a phenomenon in which the temperature difference Y becomes relatively large.

[0280] In addition, in the present embodiment, the control device 140 can make a determination related to cooling abnormality based on the time change in which the temperature difference Y increases.

[0281] Thereby, the control device 140 can suppress the concern of misjudging a situation where the temperature difference Y becomes relatively large for reasons other than the cooling structure unit 190 as a cooling abnormality of the cooling structure unit 190.

[0282] In addition, in the present embodiment, the control device 140 can determine that there is a cooling abnormality when the temperature difference Y exceeds a reference value Yth1.

[0283] Thereby, by appropriately setting the reference value Yth1, the control device 140 can specifically determine the presence or absence of a cooling abnormality in the cooling structure unit 190.

[0284] In addition, in the present embodiment, the control device 140 can correct the measured value of the temperature difference Y to the temperature difference Y when the power device is in a specified load state, and make a determination on the presence or absence of a cooling abnormality based on the corrected temperature difference Y.

[0285] Thereby, the control device 140 suppresses the influence of the load state of the power device on the temperature difference Y, and thus can more appropriately make a determination related to the cooling abnormality of the cooling structure unit 190.

[0286] In addition, in the present embodiment, the control device 140 corrects the measured value of the temperature difference Y to the temperature difference Y when the power device is in a specified load state based on the temperature of the power device (for example, the measured value of the junction temperature Tj).

[0287] Thereby, the control device 140 can specifically suppress the influence of the load state of the power device on the temperature difference Y.

[0288] In addition, in the present embodiment, the control device 140 can correct the measured value of the temperature difference Y to the temperature difference Y when the power device is in a specified load state based on the load current IL (measured value) output from the power conversion device 100.

[0289] Thereby, the control device 140 can specifically suppress the influence of the load state of the power device on the temperature difference Y.

[0290] In addition, in the present embodiment, an EEPROM 143B is included. Specifically, the EEPROM 143B can store the maximum value of the temperature difference Y during the operation of the present power conversion device 100 when the operation of the power conversion device 100 stops (when the power is OFF) in the case where the maximum value of the temperature difference Y up to the previous time (the maximum temperature difference Ymax) is updated during the operation of the present power conversion device 100. Further, the control device 140 can acquire the maximum value of the temperature difference Y up to the previous operation stop from the EEPROM 143B at the start of the operation of the power conversion device 100, and grasp the temporal change of the increase in the temperature difference Y by comparing the temperature difference Y during the operation of the power conversion device 100 and the acquired maximum value of the temperature difference Y (the maximum temperature difference Ymax).

[0291] Thereby, the control device 140 can specifically grasp the increasing tendency of the temperature difference Y.

[0292] In addition, in the present embodiment, the EEPROM 143B can cumulatively store the maximum value of the temperature difference Y between the start and stop of the operation of the power conversion device 100 when the temperature difference Y exceeding the maximum value of the temperature difference Y up to the previous operation stop (the maximum temperature difference Ymax) is generated between the start and stop of the operation of the power conversion device 100. Further, the control device 140 can predict the time required (required time TMest) for the temperature difference Y to reach the reference value Yth2 based on the update history of the maximum value of the temperature difference Y stored in the EEPROM 143B (ring buffer RB). Further, the control device 140 can determine that there is a cooling abnormality when the required time TMest is smaller than the reference time TMth.

[0293] Thereby, the control device 140 can specifically determine the presence or absence of a cooling abnormality based on the increasing tendency of the temperature difference Y.

[0294] In addition, in the present embodiment, the control device 140 can predict the required time TMest using multivariate analysis based on other information related to the operation state of the power conversion device 100 in addition to the update history of the maximum value of the temperature difference Y stored in the EEPROM 143B.

[0295] Thereby, the control device 140 can improve the prediction accuracy of the required time TMest.

[0296] In addition, in the present embodiment, the control device 140 can extract singular values from the update history of the maximum value of the temperature difference Y stored in the EEPROM 143B, and predict the required time TMest based on the update history of the maximum value of the temperature difference Y other than the singular values.

[0297] Thus, the control device 140 can improve the prediction accuracy of the required time TMest.

[0298] In addition, in the present embodiment, the control device 140 can predict the required time TMest by only considering the time when the power device is energized during the operation time of the power conversion device 100.

[0299] Thus, the control device 140 can improve the prediction accuracy of the required time TMest.

[0300] In addition, in the present embodiment, since the maximum value of the latest temperature difference Y is stored in the EEPROM 143B (circular buffer RB), the state where the maximum value of the new temperature difference Y is not stored can be set to a state where, every time the reference time OTth elapses, the (updated) history of the maximum value of the temperature difference Y stored in the EEPROM 143B can be sequentially overwritten starting from a new history, or deleted.

[0301] Thus, when the control device 140 eliminates the increasing tendency of the temperature difference Y, for example, by cleaning the heat sink unit 194, it can be set so that the data of the latest temperature difference Y cannot be used. Therefore, the control device 140 can suppress the situation where the data of the latest temperature difference Y is used to make a misjudgment related to cooling abnormality. In addition, since it is set that the control device 140 can use the data of the temperature difference Y one by one, when the degree of cleaning is simple and the increasing tendency of the temperature difference Y reappears, the retained data can be used to appropriately determine the cooling abnormality.

[0302] In addition, in the present embodiment, the control device 140 can determine the elapse of the reference time OTth by only considering the time when the power device is energized during the operation time of the power conversion device 100.

[0303] Thus, the control device 140 can more appropriately determine whether the increasing tendency of the temperature difference Y has been eliminated.

[0304] In addition, in the present embodiment, the EEPROM 143B can store the maximum value of the temperature difference Y when the temperature difference Y exceeds the reference value Yth1.

[0305] Thus, the EEPROM 143B can store only the data of the temperature difference Y (maximum value) at a level where the degree of cooling abnormality is at a relatively high level equivalent to a certain degree.

[0306] In addition, in the present embodiment, the EEPROM 143B can store the temperature difference Y (the history of the maximum value) when the temperature difference Y exceeds a reference value Yth0 smaller than the reference value Yth1. Further, when a temperature difference Y (the history of the maximum value) larger than the reference value Yth1 is stored in the EEPROM 143B and a temperature difference Y (the history of the maximum value) equal to or smaller than the reference value Yth1 stored previously is also stored, the control device 140 can determine that an abnormality exists.

[0307] Thus, when the temperature difference Y rapidly increases for reasons other than the cooling abnormality of the cooling structure 190, for example, the control device 140 can suppress a situation where it is erroneously determined that a cooling abnormality of the cooling structure 190 exists.

[0308] In addition, in the present embodiment, under the control of the control device 140, when the possibility of abnormality occurrence is eliminated, the EEPROM 143B can automatically or manually delete all of the temperature differences Y (the update history of the maximum value) stored in the ring buffer RB according to a received specified input.

[0309] Thus, when the cleaning of the heat sink 194 is performed and the increasing tendency of the temperature difference Y is completely eliminated, the control device 140 can automatically or manually delete the data of the temperature difference Y (the history of the maximum value) in the ring buffer RB.

[0310] In addition, in the present embodiment, the reference value Yth1 can be specified based on the temperature difference Y when the cooling performance of the cooling structure 190 is in a specified normal state and the temperature difference Y when the cooling fan 180 stops.

[0311] Thus, the control device 140 can specifically specify the reference value Yth1 for making a determination related to the cooling abnormality.

[0312] In addition, in the present embodiment, the power conversion device 100 can include a display device 160 and a communication device 170, which are used to notify the user of an abnormality when it is determined by the control device 140 that an abnormality exists.

[0313] Thus, the power conversion device 100 can notify the user of a cooling abnormality of the cooling structure 190 through the display device 160 and the communication device 170.

[0314] In addition, in the present embodiment, the power conversion device 100 (the control device 140) can send data related to the operating state of the power conversion device 100, including data related to the cooling abnormality, to the terminal device 300 and display it on the display unit 310 of the terminal device 300.

[0315] Thus, the power conversion device 100 can provide information related to cooling anomalies to the user through an external terminal device 300.

[0316] In addition, in the present embodiment, the power conversion device 100 may include a display device 160 for displaying information related to the operating state of the power conversion device 100, including information related to cooling anomalies.

[0317] Thus, the power conversion device 100 can visually provide information related to cooling anomalies to the user through the display device 160.

[0318] In addition, in the present embodiment, the power conversion device 100 (control device 140) may display information related to cooling anomalies as numerical values on the display device 160.

[0319] Thus, the power conversion device 100 (control device 140) can more appropriately provide information related to cooling anomalies to the user.

[0320] In addition, in the present embodiment, the power conversion device 100 (control device 140) may cause the arithmetic device 200 to perform arithmetic processing related to the determination of cooling anomalies.

[0321] Thus, the power conversion device 100 (control device 140) can reduce the processing load related to the determination of cooling anomalies, and thus can, for example, suppress a situation where the processing related to the determination of cooling anomalies affects the control processing of the inverter circuit 130 and the like.

[0322] In addition, in the present embodiment, the control device 140 may accumulate data related to the temperature difference Y and data related to the operating mode of the power conversion device 100 in the arithmetic device 200, the terminal device 300, and the like. And the control device 140 may perform a determination related to cooling anomalies based on the data accumulated in the arithmetic device 200, the terminal device 300, and the like.

[0323] Thus, the control device 140 can cause the processing of accumulating data to be performed externally only by appropriately uploading the data for determining cooling anomalies.

[0324] As described above, the embodiments have been described in detail, but the present invention is not limited to specific embodiments, and various modifications / changes can be made within the scope of the gist described in the claims.

Claims

1. A power conversion device, comprising: a power device; a cooling structure unit for dissipating heat of the above-mentioned power device; a blowing unit for blowing air to the above-mentioned cooling structure unit; a determination unit for making a determination related to an abnormality in the cooling performance of the above-mentioned cooling structure unit based on the time change of the increase in the temperature difference between the temperature of the above-mentioned cooling structure unit and the temperature of the air inside the power conversion device; and a non-volatile storage unit, when the above-mentioned storage unit generates a temperature difference exceeding the maximum value of the above-mentioned temperature difference until the previous power-off during the period from the power-on to the power-off of the power conversion device, the maximum value of the above-mentioned temperature difference between the current power-on and the power-off of the power conversion device is cumulatively stored when the power of the power conversion device is turned off, the above-mentioned determination unit predicts the time required for the above-mentioned temperature difference to reach a specified second reference value based on the update history of the maximum value of the above-mentioned temperature difference stored in the above-mentioned storage unit, and determines that there is the above-mentioned abnormality when the predicted above-mentioned required time is shorter than a specified first reference time.

2. The power conversion device according to claim 1, wherein, the above-mentioned determination unit corrects the measured value of the above-mentioned temperature difference to the above-mentioned temperature difference when the above-mentioned power device is in a specified load state, and makes a determination related to the above-mentioned abnormality based on the corrected above-mentioned temperature difference.

3. The power conversion device according to claim 2, wherein, the above-mentioned determination unit corrects the measured value of the above-mentioned temperature difference to the above-mentioned temperature difference when the above-mentioned power device is in the above-mentioned specified load state based on the temperature of the above-mentioned power device.

4. The power conversion device according to claim 2, wherein, the above-mentioned determination unit corrects the measured value of the above-mentioned temperature difference to the above-mentioned temperature difference when the above-mentioned power device is in the above-mentioned specified load state based on the load current output by the power conversion device.

5. The power conversion device according to claim 1, wherein, in addition to based on the update history of the maximum value of the above-mentioned temperature difference stored in the above-mentioned storage unit, the above-mentioned determination unit also uses multivariate analysis to predict the above-mentioned required time based on other information related to the operating state of the power conversion device.

6. The power conversion device according to claim 1 or 5, wherein, the above-mentioned determination unit extracts singular values from the update history of the maximum value of the above-mentioned temperature difference stored in the above-mentioned storage unit, and predicts the above-mentioned required time based on the update history of the maximum value of the above-mentioned temperature difference other than the above-mentioned singular values.

7. The power conversion device according to claim 1 or 5, wherein, the above-mentioned determination unit predicts the above-mentioned required time only considering the time when the above-mentioned power device is energized during the operating time of the power conversion device.

8. The power conversion device according to claim 1 or 5, wherein, After storing the maximum value of the latest temperature difference in the storage unit, when the state where the maximum value of the new temperature difference is not stored continues for a specified second reference time, it is set to a state where a new history record of the maximum value of the temperature difference that can be stored in the storage unit starts to be overwritten in order, or is deleted.

9. The power conversion device according to claim 8, wherein the determination unit determines the passage of the second reference time only considering the time during which the power device is energized during the operation time of the power conversion device.

10. The power conversion device according to claim 1 or 5, wherein when the possibility of the occurrence of the abnormality is eliminated, the storage unit automatically deletes all the stored maximum values of the temperature difference, or manually deletes all the stored maximum values of the temperature difference according to a specified input received.

11. The power conversion device according to claim 1 or 5, wherein it further includes a notification unit for notifying a user of the abnormality when the determination unit determines the existence of the abnormality.

12. The power conversion device according to claim 1 or 5, wherein data related to the operating state of the power conversion device including data related to the abnormality is transmitted to a first external device, and the display unit of the first external device displays it.

13. The power conversion device according to claim 1 or 5, wherein it further includes a display unit for displaying information related to the operating state of the power conversion device including information related to the abnormality.

14. The power conversion device according to claim 12, wherein the display unit displays the information related to the abnormality as a numerical value.

15. The power conversion device according to claim 1 or 5, wherein a second external device is made to execute arithmetic processing related to the determination of the abnormality.

16. The power conversion device according to claim 1 or 5, wherein the determination unit causes a third external device to accumulate data related to the temperature difference and data related to the operation mode of the power conversion device, and based on the data accumulated in the third external device, makes a determination related to the abnormality.

17. A cooling abnormality determination device, which is a cooling abnormality determination device for a power conversion device, the power conversion device including: a power device; a cooling structure unit for dissipating heat of the power device; a blower unit for blowing air to the cooling structure unit; and a non-volatile storage unit, the cooling abnormality determination device makes a determination related to an abnormality in the cooling performance of the cooling structure unit based on the time change of the increase in the temperature difference between the temperature of the cooling structure unit and the temperature of the air inside the power conversion device. In the above storage unit, between the power-on and power-off of the power conversion device, when a temperature difference exceeding the maximum value of the temperature difference up to the previous power-off occurs, the maximum value of the temperature difference between the current power-on and power-off is cumulatively stored when the power conversion device is powered off. Based on the update history of the maximum value of the temperature difference stored in the above storage unit, the time required for the temperature difference to reach a specified second reference value is predicted, and when the predicted time required is shorter than a specified first reference time, it is determined that the above abnormality exists.

18. A cooling abnormality determination method, which is a cooling abnormality determination method for a power conversion device, the power conversion device including: Power devices; A cooling structure unit provided with a plurality of heat sinks for dissipating heat of the above power devices; A blower unit for blowing air to the above cooling structure unit; and A non-volatile storage unit, This cooling abnormality determination method makes a determination related to an abnormality in the cooling performance of the above cooling structure unit based on the time change of the increase in the temperature difference between the temperature of the above cooling structure unit and the temperature of the air inside the power conversion device. In the above storage unit, between the power-on and power-off of the power conversion device, when a temperature difference exceeding the maximum value of the temperature difference up to the previous power-off occurs, the maximum value of the temperature difference between the current power-on and power-off is cumulatively stored when the power conversion device is powered off. Based on the update history of the maximum value of the temperature difference stored in the above storage unit, the time required for the temperature difference to reach a specified second reference value is predicted, and when the predicted time required is shorter than a specified first reference time, it is determined that the above abnormality exists.

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