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

Abstract

The invention provides a power conversion apparatus, a cooling abnormality determination apparatus, and a cooling abnormality determination method, which can more appropriately determine an abnormality related to the cooling performance of a power device based on a cooling structure part such as a cooling fin of the power conversion apparatus. A power conversion device (100) according to one embodiment of the present invention is provided with: power devices (SD, SW); a cooling structure section (190) for dissipating heat from the power device; a cooling fan (180) for blowing air to the cooling structure part (190); and a control device (140) that determines an abnormality in the cooling performance of the cooling structure (190) on the basis of the temperature difference (Y) between the temperature (Tf) of the cooling structure (190), i.e., the fin section (194), and the internal air temperature (Ta), i.e., the temperature of the air inside the case of the power conversion device (100).

Description

[0001] This application is a divisional application of the following application:

[0002] Invention Title: Power Conversion Device, Cooling Abnormality Determination Device, and Cooling Abnormality Determination Method

[0003] Application date: August 26, 2021

[0004] Application number: 202110986264.9 Technical Field

[0005] The present invention relates to a power conversion device and the like. Background Art

[0006] For example, there is a known method for determining cooling abnormalities caused by, for example, blockage of a cooling structure for heat dissipation of a power device in a power conversion device that converts externally input power into power of a predetermined voltage and frequency to drive a load device (see Patent Documents 1 and 2).

[0007] <Prior Art Literature>

[0008] <Patent Document>

[0009] Patent Document 1: Japanese Patent No. 6591642

[0010] Patent Document 2: Japanese Patent No. 5593051 Summary of the Invention

[0011] <Problems to be Solved by the Invention>

[0012] However, in Patent Document 1, cooling anomalies caused by heat sink blockage and other factors are determined based on temperature changes measured at multiple locations within the power conversion device. Therefore, the measured temperature changes may be influenced by fluctuations in the power conversion device's load state, potentially reducing the accuracy of heat sink cooling anomaly determinations.

[0013] Furthermore, in Patent Document 2, the power converter is forcibly stopped when a heating condition occurs. In addition to the internal temperature of the power converter, the load condition of the power converter is also used to determine cooling anomalies caused by, for example, blockage of the air intake port for drawing air toward the heat sink. Therefore, while consideration of the load condition of the power converter can be expected to improve determination accuracy, this assumes the occurrence of a heating anomaly, which results in the forced shutdown of the power converter. Therefore, it cannot determine cooling anomalies before the power converter is forced to shut down.

[0014] Therefore, in view of the above problems, an object of the present invention is to provide a technology that can more appropriately determine an abnormality related to the cooling performance of a power device by a cooling structure such as a heat sink of a power conversion device.

[0015] <Methods used to solve the problem>

[0016] In order to achieve the above-mentioned object, in one embodiment of the present invention, a power conversion device is provided, comprising:

[0017] Power devices;

[0018] A cooling structure for dissipating heat from the power device;

[0019] an air supply unit for supplying air to the cooling structure; and

[0020] A determination unit determines whether there is an abnormality in the cooling performance of the cooling structure based on a temperature difference between the temperature of the cooling structure and the temperature of air inside the power conversion device.

[0021] In addition, in another embodiment of the present invention, a cooling abnormality determination device is provided, which is a cooling abnormality determination device for a power conversion device, and the power conversion device includes:

[0022] Power devices;

[0023] A cooling structure for dissipating heat from the power device; and

[0024] The air supply unit is used to supply air to the cooling structure.

[0025] The cooling abnormality determination device makes a determination regarding abnormality in the cooling performance of the cooling structure based on a temperature difference between the temperature of the cooling structure and the temperature of air inside the power conversion device.

[0026] In another embodiment of the present invention, a cooling abnormality determination method is provided, which is a cooling abnormality determination method for a power conversion device, the power conversion device comprising:

[0027] Power devices;

[0028] A cooling structure for dissipating heat from the power device; and

[0029] The air supply unit is used to supply air to the cooling structure.

[0030] The cooling abnormality determination method makes a determination regarding abnormality in the cooling performance of the cooling structure based on a temperature difference between the temperature of the cooling structure and the temperature of air inside a power conversion device.

[0031] <Effects of the Invention>

[0032] According to the above embodiment, it is possible to more appropriately determine an abnormality related to the cooling performance of a power device caused by a cooling structure such as a heat sink of a power conversion device. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a diagram showing an example of the configuration of a cooling abnormality determination system.

[0034] Figure 2 This is a diagram showing an example of the configuration of a control device.

[0035] Figure 3 This is a schematic diagram showing an example of a cooling structure of a power conversion device.

[0036] Figure 4 This is a flowchart schematically showing an example of data acquisition processing related to determination of cooling abnormality.

[0037] Figure 5 This is a flowchart schematically showing an example of the end processing related to the determination of cooling abnormality.

[0038] Figure 6 This is a flowchart schematically showing an example of a startup process related to determination of cooling abnormality.

[0039] Figure 7 This is a flowchart schematically showing an example of a cooling abnormality determination process.

[0040] Figure 8 This is a flowchart schematically showing an example of a process for determining whether cooling abnormality has been alleviated.

[0041] Figure 9 This is a diagram for explaining an example of an operation related to determination of cooling abnormality by the control device.

[0042] Figure 10 This is a flowchart schematically showing another example of the data acquisition process related to the determination of cooling abnormality.

[0043] Figure 11 This is a diagram for explaining another example of the operation related to the determination of cooling abnormality by the control device.

[0044] Figure 12 This is a flowchart schematically showing another example of the cooling abnormality determination process.

[0045] Description of Reference Numerals

[0046] 1 Cooling abnormality judgment system

[0047] 100 Power conversion device

[0048] 110 Rectifier Circuit

[0049] 110A circuit board

[0050] 120 Smoothing Circuit

[0051] 130 Inverter Circuit

[0052] 130A circuit board

[0053] 140 Control device (determination unit, cooling abnormality determination device)

[0054] 141 CPU

[0055] 142 Memory devices

[0056] 142A, 142B RAM

[0057] 143 Auxiliary storage device

[0058] 143A ROM

[0059] 143B EEPROM (storage unit)

[0060] 144 interfaces

[0061] 150 sensors

[0062] 160 display device (notification unit, display unit)

[0063] 170 Communication device (notification department)

[0064] 180 Cooling fan (air supply unit)

[0065] 190 Cooling structure

[0066] 192 heat sink base

[0067] 194 heat sink

[0068] 194A heat sink

[0069] 200 computing device (second external device, third external device, cooling abnormality determination device)

[0070] 300 Terminal device (first external device, third external device, cooling abnormality determination device)

[0071] 310 Display Unit

[0072] M Motor

[0073] PS Commercial Power Supply

[0074] RB Ring Buffer

[0075] SD semiconductor diode (power device)

[0076] SW semiconductor switch (power device) DETAILED DESCRIPTION

[0077] Hereinafter, the embodiments will be described with reference to the accompanying drawings.

[0078] [Composition of the cooling abnormality judgment system]

[0079] First, refer to Figure 1 、 Figure 2 , the structure of the cooling abnormality determination system 1 of this embodiment is described.

[0080] Figure 1 1 is a diagram showing an example of the configuration of the cooling abnormality determination system 1 according to the present embodiment. Figure 2 1 is a diagram showing an example of the configuration of the control device 140 in the cooling abnormality determination system 1 according to the present embodiment.

[0081] The cooling abnormality determination system 1 of the present embodiment is used to determine the presence or absence of abnormality related to the cooling performance of the power conversion device 100 .

[0082] like Figure 1 As shown, the cooling abnormality determination system 1 includes a power conversion device 100 , a computing device 200 , and a terminal device 300 .

[0083] The power conversion device 100 converts three-phase AC power (e.g., R phase, S phase, and T phase) input from a commercial power supply PS into three-phase AC power (e.g., U phase, V phase, and W phase) having a predetermined voltage and a predetermined frequency, thereby driving the motor M.

[0084] The electric motor M drives a predetermined machine such as a winding machine installed in a textile factory, for example, based on the three-phase AC power output from the power conversion device 100 .

[0085] It should be noted that the power conversion device 100 can generate three-phase AC power for driving the motor M based on three-phase AC power input from a power source other than the commercial power source. Alternatively, the power conversion device 100 can generate three-phase AC power for driving the motor M based on power input from a DC power source. In this case, the DC power is input to the DC connection portion (positive line PL and negative line NL) between the rectifier circuit 110 and the inverter circuit 130, which will be described later.

[0086] 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 .

[0087] The rectifier circuit 110 is configured to rectify the three-phase AC power of the R phase, S phase, and T phase input from the commercial power supply PS, thereby outputting DC power. The positive and negative output terminals of the rectifier circuit 110 are connected to one end of the positive line PL and the negative line NL, respectively, and the DC power is output to the smoothing circuit 120 via 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) (see Figure 3 ), which is a bridge full-wave rectifier circuit in which three groups of series-connected semiconductor diodes SD constituting upper and lower bridge arms are connected in parallel.

[0088] The smoothing circuit 120 is used to suppress ripples in the DC power output from the rectifier circuit 110 and the DC power regenerated from the inverter circuit 130 , thereby smoothing them.

[0089] The smoothing circuit 120 includes, for example, a smoothing capacitor.

[0090] A smoothing capacitor may be provided in parallel with the rectifier circuit 110 and the inverter circuit 130 in a path connecting the positive line PL and the negative line NL.

[0091] The smoothing capacitor smoothes the DC power output from the rectifier circuit 110 and the DC power output (regenerated) from the inverter circuit 130 while repeating charging and discharging as appropriate.

[0092] There may be one smoothing capacitor. Alternatively, multiple smoothing capacitors may be provided, and multiple smoothing capacitors may be connected in parallel or in series between the positive line PL and the negative line NL. Alternatively, multiple smoothing capacitors may be configured by connecting two or more smoothing capacitors in series between the positive line PL and the negative line NL.

[0093] In addition, the smoothing circuit 120 includes, for example, a reactor.

[0094] The reactor may be provided on the positive line PL between the rectifier circuit 110 and the smoothing capacitor (specifically, at a branch point with a path where the smoothing capacitor is provided).

[0095] The reactor smoothes the DC power output from the rectifier circuit 110 and the DC power output (regenerated) from the inverter circuit 130 while appropriately generating a voltage to prevent changes in current.

[0096] The positive and negative input terminals of the inverter circuit 130 are connected to the other ends of the positive line PL and the negative line NL. The inverter circuit 130 is connected to the positive line PL and the negative line NL via a semiconductor switch SW (an example of a power device) (see Figure 3 ) converts the DC power supplied from the smoothing circuit 120 into three-phase AC power (e.g., U-phase, V-phase, and W-phase) with a predetermined frequency and voltage, and outputs the converted power to the motor M. The semiconductor switch SW may be, for example, an IGBT (Insulated Gate Bipolar Transistor) or a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) made of silicon (Si). Alternatively, the semiconductor switch SW may be a semiconductor element using a wide-bandgap semiconductor such as silicon carbide (SiC) or gallium nitride (GaN).

[0097] Inverter circuit 130, for example, includes six semiconductor switches SW and is configured as a bridge circuit comprising three series-connected pairs of two semiconductor switches SW forming upper and lower bridge arms (switch bridge arms) connected in parallel between a positive line PL and a negative line NL. Inverter circuit 130 can output three-phase AC power via the U-phase line, the V-phase line, and the W-phase line extending from the connection point of the three upper and lower bridge arms. Furthermore, a freewheeling diode can be connected in parallel to each of the six semiconductor switches SW.

[0098] The control device 140 performs control related to the power conversion device 100 .

[0099] The functions of the control device 140 can be implemented by arbitrary hardware or a combination of arbitrary hardware and software.

[0100] like Figure 2 As shown, the control device 140 is primarily composed of, for example, a computer including a CPU 141 (Central Processing Unit), a memory device 142, a nonvolatile auxiliary storage device 143, and an interface 144. The control device 140 performs various controls by loading programs installed in the auxiliary storage device 143 into the memory device 142 and causing the CPU 141 to execute the programs. Furthermore, the control device 140 receives external signals through the interface 144 and outputs (transmits) signals to the outside.

[0101] like Figure 2 As shown, the memory device 142 includes RAM (Random Access Memory) 142A and 142B.

[0102] The auxiliary storage device 143 includes a ROM (Read Only Memory) 143A and an EEPROM (Electrically Erasable Programmable Read-Only Memory) 143B. A ring buffer RB, which will be described later, is set in the EEPROM 143B (an example of a storage unit).

[0103] It should be noted that the ring buffer RB can be set to RAM142A or RAM142B.

[0104] The control device 140 (an example of a determination unit or cooling abnormality determination device) outputs a drive signal to the inverter circuit 130 (specifically, the gates of each semiconductor switch SW), thereby driving the motor M using the inverter circuit 130 so that the motor M meets predetermined operating conditions. In other words, the control device 140 generates a control signal for driving the motor M according to the predetermined operating conditions and outputs it to the inverter circuit 130.

[0105] Furthermore, the control device 140 determines whether there is any abnormality related to the cooling performance of the power conversion device 100. Specifically, the control device 140 determines whether there is any abnormality related to the cooling performance of the cooling structure 190, which is used to dissipate heat generated by losses during energization of the semiconductor diode SD and semiconductor switch SW, which will be described later. Details will be described later.

[0106] The sensor 150 acquires detection information related to the operating state (operating status) of the power conversion device 100. The sensor 150 is connected to the control device 140 via, for example, a one-to-one communication line, and a signal corresponding to the detection information (hereinafter referred to as a "detection signal") is input to the control device 140. This allows the control device 140 to control the power conversion device 100 based on the detection signal from the sensor 150.

[0107] The sensor 150 includes, for example, various temperature sensors. For example, a heat sink temperature sensor for detecting the temperature Tf of the heat sink 194 (hereinafter referred to as the "heat sink temperature"), as described later, may be included. Another temperature sensor may include, for example, an indoor air temperature sensor for detecting the temperature Ta of the air inside the housing of the power conversion device 100 (hereinafter referred to as the "indoor air temperature"), as described later.

[0108] The sensor 150 includes, for example, various current sensors, voltage sensors, etc. The current sensor may include, for example, a load current sensor for detecting the load current IL output to the motor M.

[0109] The display device 160 (an example of a notification unit or display unit) is provided, for example, on the outer surface of the housing of the power conversion device 100. The display device 160 displays information related to the operating state (operating state) of the power conversion device 100 under the control of the control device 140.

[0110] It should be noted that the display device 160 may be provided outside the housing of the power conversion device 100 , for example, may be provided on the surface (outer surface) of the housing of a predetermined machine electrically driven by the motor M.

[0111] The communication device 170 (an example of a notification unit) communicates with devices external to the power conversion device 100 , such as the computing device 200 and the terminal device 300 , via a predetermined communication line.

[0112] The prescribed communication line may be, for example, a one-to-one communication line. Furthermore, the prescribed communication line may include a local area network (LAN), such as a field network constructed within a facility (factory) where the prescribed machine driven by the motor M is installed. A local area network may be wired, wireless, or both. Furthermore, the prescribed communication line may include, for example, a wide area network (WAN) outside the facility (factory) where the prescribed machine driven by the motor M is installed. Examples of wide area networks include mobile communication networks with base stations as terminals, satellite communication networks using communication satellites, and the Internet. Furthermore, the prescribed communication line may include, for example, short-range communication lines based on prescribed wireless communication standards such as Bluetooth (registered trademark) and WiFi.

[0113] It should be noted that the functions of the communication device 170 can be incorporated into the control device 140 (interface 144).

[0114] The cooling fan 180 (an example of an air supply unit) supplies air to a cooling structure 190 (specifically, the heat dissipation fins 194 ) to be described later, thereby promoting heat dissipation of the cooling structure 190 .

[0115] The housing of the power conversion device 100 is provided with an intake port (intake port) for external air and an outlet (exhaust port) for internal air. The cooling fan 180 is located upstream of the cooling structure 190 in the air flow path from the intake port to the exhaust port. In this case, the cooling fan 180 draws external air from the intake port and sends it toward the cooling structure 190, causing the relatively low-temperature external air to reach the cooling structure 190. Heat exchange with the cooling structure 190 causes the heated air to be discharged through the exhaust port. Alternatively, the cooling fan 180 can be located downstream of the cooling structure 190 in the air flow path from the intake port to the exhaust port. In this case, the cooling fan 180 draws air from the periphery of the cooling structure 190 and creates a flow of air from the upstream intake port toward the cooling structure 190, causing the relatively low-temperature external air to reach the cooling structure 190.

[0116] The computing device 200 (an example of a second external device) is provided outside the power conversion device 100 and is used to perform various computing processes.

[0117] The computing device 200 can be communicatively connected to the power conversion device 100 via a predetermined communication line, for example, and can perform computing processing related to the control of the power conversion device 100 in accordance with instructions from the control device 140. Specifically, the computing device 200 can perform part or all of the computing processing related to the determination of cooling abnormality, which will be described later, in accordance with instructions from the control device 140.

[0118] The computing device 200 may be, for example, a PLC (Programmable Logic Controller) or an edge controller for controlling a predetermined machine electrically driven by the motor M. Alternatively, the computing device 200 may be, for example, a computer terminal.

[0119] The computing device 200 may be, for example, a server device. The server device may be a cloud server installed outside a facility (factory) where a predetermined machine electrically driven by the motor M is installed. Alternatively, the server device may be, for example, an edge server installed within a facility (factory) where a predetermined machine electrically driven by the motor M is installed, or in a communication facility (e.g., a base station, a shield) located near the facility.

[0120] The terminal device 300 (an example of a first external device) is located outside the power conversion device 100 and is used by the user of the power conversion device 100 (cooling abnormality determination system 1). For example, the terminal device 300 provides various information to the user via the display unit 310, and receives various inputs from the user and transmits them to the power conversion device 100.

[0121] The terminal device 300 may include a stationary terminal device such as a desktop computer terminal. Alternatively, the terminal device 300 may include a portable (portable) terminal device (portable terminal) such as a smartphone, a tablet terminal, or a laptop computer terminal.

[0122] [Cooling Structure of Power Converter]

[0123] Next, refer to Figure 3 , the cooling structure 190 of the power conversion device 100 is described.

[0124] Figure 3 1 is a schematic diagram illustrating an example of the cooling structure 190 of the power conversion device 100 .

[0125] The cooling structure 190 corresponds to, for example, a radiator, and includes a fin base 192 and a fin portion 194 .

[0126] The heat sink base 192 has a flat plate shape with a predetermined thickness. A heat sink portion 194 is provided on one surface (the lower surface in the figure) of the flat plate of the heat sink base 192, and circuit boards 110A and 130A, corresponding to the rectifier circuit 110 and inverter circuit 130, are placed on the other surface (the upper surface in the figure).

[0127] Heat sink base 192 is made of a material with relatively high thermal conductivity. This allows heat energy generated by losses in semiconductor diode SD and semiconductor switch SW during energization to more easily flow to heat sink base 192. Heat sink base 192 can be made of a metal such as aluminum, iron, or copper. The same applies to heat sink portion 194.

[0128] As described above, fin section 194 is provided on one surface of the flat plate of fin base 192. Fin section 194 includes a plurality of fins 194A projecting away from the surface of fin base 192 (in the negative Z-axis direction in the figure).

[0129] The plurality of heat sinks 194A each have a very thin flat plate shape, and are arranged at substantially equal intervals along a predetermined direction (the X-axis direction in the figure) on one surface of the heat sink base 192 .

[0130] Each of the multiple heat sinks 194A is constructed from a member with relatively high thermal conductivity. This facilitates the flow of heat energy generated by losses in the semiconductor diodes SD and semiconductor switches SW during power-on from the heat sink base 192 to the multiple heat sinks 194A. Furthermore, the multiple heat sinks 194A have a relatively large surface area. This provides a relatively large area of ​​contact between the multiple heat sinks 194A and the air, making it easier to dissipate heat energy into the surrounding air. Consequently, heat energy generated by losses in the semiconductor diodes SD and semiconductor switches SW during power-on is easily dissipated into the air, thereby improving the cooling performance of the power conversion device 100.

[0131] Furthermore, cooling fan 180 directs cooling air CA in a direction perpendicular to the direction (the Y-axis in the figure) in which the multiple heat sinks 194A are arranged (the X-axis). This allows the cooling air CA to pass between the multiple heat sinks 194A, maintaining a relatively low temperature in the air surrounding the multiple heat sinks 194A. Consequently, the temperature difference between the heat sinks 194A and the surrounding air becomes relatively large, allowing heat energy to be dissipated to the surrounding air more easily. This facilitates heat dissipation to the air due to losses in the semiconductor diodes SD and semiconductor switches SW during energization, further improving the cooling performance of the power conversion device 100 and ensuring the required cooling performance of the power conversion device 100.

[0132] On the other hand, depending on the environment in which the power converter 100 is installed, foreign matter may become lodged between the multiple fins 194A. Furthermore, depending on the size of the foreign matter, it may also clog the air intake port of the power converter 100 housing. For example, in a textile factory, the air may contain not only dust but also cotton, which may clog the air intake port between the multiple fins 194A or the housing of the power converter 100. Consequently, the cooling air CA may not reach the fins 194A corresponding to the areas blocked by foreign matter, or the amount of external air drawn in through the air intake port may decrease, causing the temperature of the air supplied to the fin section 194 to rise. Consequently, the cooling performance of the semiconductor diode SD and semiconductor switch SW by the cooling structure 190 may deteriorate, resulting in an abnormality related to the cooling performance of the power converter 100 (the semiconductor diode SD and semiconductor switch SW) by the cooling structure 190 (hereinafter referred to as a "cooling abnormality"). Furthermore, depending on the extent of the cooling abnormality, the power conversion device 100 may need to be forcibly stopped, which may affect the operation of machinery in a factory where predetermined machinery electrically driven by the motor M is installed.

[0133] It should be noted that the cooling structure 190 can be of any design as long as it facilitates the dissipation of heat energy generated by losses during energization of the semiconductor diode SD and the semiconductor switch SW to the surrounding air. For example, the heat sink 194A can be a single structure rather than multiple structures. Furthermore, the heat sink base 192 can be provided with one or more rod-shaped or needle-shaped protrusions made of a relatively high thermal conductivity member, in place of the heat sink 194A.

[0134] [An Example of Operation Related to Determination of Cooling Abnormality in a Power Converter]

[0135] Next, refer to Figures 4 to 9 , an example of an operation related to determination of cooling abnormality of the power conversion device 100 is described.

[0136] In this example, the control device 140 diagnoses cooling anomalies (hereinafter, for convenience, referred to as "blockage anomalies") caused by foreign matter blocking the spaces between the heat sink 194 (plural heat sinks 194A) and the air intake of the housing of the power conversion device 100. The function of the control device 140 to diagnose blockage anomalies of the heat sink 194 and other components (hereinafter, referred to as the "heat sink blockage diagnostic function") can be configured to switch between an active state (ON) and an inactive state (OFF) based on external input. For example, a user can switch the heat sink blockage diagnostic function ON or OFF using a predetermined input provided on a predetermined machine electrically driven by the power conversion device 100 or the motor M. Alternatively, a user can switch the heat sink blockage diagnostic function ON or OFF using a predetermined input to the terminal device 300. In this case, a signal corresponding to the input from the terminal device 300 is transmitted to the power conversion device 100 via a predetermined communication line and then enters the control device 140 via the communication device 170. Thus, the control device 140 can switch the heat sink clogging diagnosis function between the ON state and the OFF state according to the input from the user.

[0137] Specifically, control device 140 determines whether fin section 194 is clogged based on the temperature difference Y between fin temperature Tf and indoor air temperature Ta. This is because if foreign matter clogs fin section 194 or the air intake of power conversion device 100, air will have difficulty reaching fins 194A. As a result, heat dissipation of fins 194A to the air becomes insufficient, and temperature difference Y becomes relatively large (increases).

[0138] <Control Processing Related to Determination of Cooling Abnormality>

[0139] Figures 4 to 81 is a diagram showing an example of a control process related to the determination of cooling abnormality by the control device 140. Specifically, Figure 4 This is a flowchart schematically showing an example of data acquisition processing related to the determination of cooling abnormality by the control device 140. Figure 5 This is a flowchart schematically showing an example of the end processing related to the determination of cooling abnormality by the control device 140. Figure 6 This is a flowchart schematically showing an example of a startup process related to the determination of cooling abnormality by the control device 140 . Figure 7 This is a flowchart schematically showing an example of a cooling abnormality determination process performed by the control device 140 . Figure 8 This is a flowchart schematically showing an example of a determination process of whether the cooling abnormality has been alleviated by the control device 140 .

[0140] first, Figure 4 For example, the flowchart is repeatedly executed in each predetermined control cycle during the operation of the power conversion device 100, that is, from the start of operation (specifically, the power supply of the control device 140 is turned on) to the stop of operation (specifically, the power supply of the control device 140 is turned off). Figure 12 The flowchart can also be the same.

[0141] like Figure 4 In step S102, the control device 140 (CPU 141) determines whether the heat sink clogging diagnostic function is in the ON state. If the heat sink clogging diagnostic function is in the ON state, the CPU 141 proceeds to step S104. If it is in the OFF state, the processing of this flowchart ends.

[0142] It should be noted that the heat sink blockage diagnosis function can be fixed to a state of being always effective. In this case, the processing of step S102 is omitted. Figure 12 The same can be done for step S702.

[0143] In step S104 , the CPU 141 calculates the temperature difference Y (=Tf−Ta) between the fin temperature Tf and the indoor air temperature Ta as a determination indicator of the presence or absence of the clogging abnormality of the fin portion 194 .

[0144] For example, the CPU 141 can calculate the temperature difference Y based on the difference between the heat sink temperature Tf measured by the heat sink temperature sensor and the inside air temperature Ta measured by the inside air temperature sensor. Hereinafter, the temperature difference Y based on the difference between the heat sink temperature Tf measured by the heat sink temperature sensor and the inside air temperature Ta measured by the inside air temperature sensor may be referred to as the "measured value of the temperature difference Y."

[0145] Furthermore, the CPU 141 can correct the measured value of the temperature difference Y to the value of the temperature difference Y under a predetermined load condition of the power conversion device 100 (hereinafter referred to as the "reference load condition"), which serves as a reference. This allows the influence of the load condition of the power conversion device 100 to be somewhat eliminated from the temperature difference Y, which serves as a criterion for determining whether the heat sink 194 is clogged. This is because the heat sink temperature Tf varies depending on the load condition of the power conversion device 100, i.e., the heat generated by the losses in the semiconductor diode SD and the semiconductor switch SW, the ambient temperature, and other factors.

[0146] For example, CPU 141 can correct the measured value of temperature difference Y based on the estimated value of junction temperature Tj, thereby obtaining a corrected value of temperature difference Y for the reference load state of power conversion device 100. This is because it is known that junction temperature Tj does not change due to the influence of the airflow to heat sink 194, etc., but changes with the load state of power conversion device 100. Specifically, CPU 141 can estimate (calculate) the losses of power devices (semiconductor diode SD, semiconductor switch SW), and obtain (calculate) the estimated value of junction temperature Tj based on the estimated losses. Furthermore, CPU 141 can use a conversion formula or conversion map for obtaining the corrected value of temperature difference Y to obtain the corrected value of temperature difference Y from the measured value of temperature difference Y and the estimated value of junction temperature Tj.

[0147] Alternatively, for example, the CPU 141 can correct the measured value of the temperature difference Y based on the load current IL measured by the load current sensor, thereby obtaining a corrected value of the temperature difference Y under the reference load state of the power conversion device 100. This is because the magnitude of the load current IL varies depending on 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 using a conversion formula or conversion map. Furthermore, the CPU 141 can obtain a 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 using a conversion formula or conversion map for obtaining the corrected value of the temperature difference Y. Furthermore, the CPU 141 can convert the measured value of the load current IL into an index value used to correct the unit of temperature of the temperature difference Y, and use this index value to obtain the corrected value of the temperature difference Y.

[0148] It should be noted that the above-mentioned conversion formula and conversion diagram are determined in advance through, for example, experiments and simulations related to the power conversion device 100.

[0149] After completing the processing of step S104, CPU 141 proceeds to step S106.

[0150] In step S106, CPU 141 determines whether the temperature difference Y calculated in step S104 exceeds a reference value Yth1. Reference value Yth1 (an example of a first reference value) can be determined in advance, for example, through experiments, simulations, or the like, as a lower limit for determining whether fin 194 is clogged. Alternatively, reference value Yth1 can be determined in advance based on at least one of a logical method and an approximate method, for example, the temperature difference Y when the cooling performance of cooling structure 190 is in a predetermined normal state and the temperature difference Y when cooling fan 180 is stopped. Furthermore, reference value Yth1 is set to a value somewhat lower than reference value Yth2 (an example of a second reference value), which corresponds to the temperature difference Y when power converter 100 is forced to stop due to a cooling anomaly. If temperature difference Y exceeds reference value Yth1, CPU 141 proceeds to step S108. If not, the process in this flowchart ends.

[0151] In step S108, the CPU 141 determines whether the temperature difference Y calculated in step S104 exceeds the maximum temperature difference Ymax. The maximum temperature difference Ymax corresponds to the maximum value of the temperature difference Y recorded in the ring buffer RB in the predetermined storage area of ​​the EEPROM 143B, and is stored in the RAM 142B (see Figure 6 If the temperature difference Y calculated in step S104 exceeds the maximum temperature difference Ymax, the CPU 141 proceeds to step S110. If the temperature difference Y does not exceed the maximum temperature difference Ymax, the CPU 141 ends the processing of this flowchart.

[0152] In step S110, the CPU 141 sets the maximum temperature difference Ymax as the temperature difference Y calculated in step S104. In this way, the CPU 141 can use the temperature difference Y in the current flowchart as the maximum temperature difference Ymax in the next flowchart and the following.

[0153] After completing the processing of step S110, CPU 141 proceeds to step S112.

[0154] In step S112, the CPU 141 stores the operating time OT to date, the current heat sink temperature Tf, the indoor air temperature Ta, and the temperature difference Y in the RAM 142B. The operating time OT represents the operating time of the power conversion device 100 since the last reset. As will be described later, the operating time OT is reset (cleared) when the temperature difference Y exceeding the past maximum temperature difference Ymax is recorded in the ring buffer RB (see Figure 5), thus corresponding to the operating time of the power conversion device 100 after the previous maximum temperature difference Ymax was obtained. For example, the CPU 141 can calculate the operating time OT by reading the operating time OT at the end of the previous operation from the EEPROM 143B and, using a clock counter, adding the operating time OT at the end of the previous operation to the operating time since the current startup. The operating time OT may include the entire period from the start-up to the shutdown of the power conversion device 100. Alternatively, the operating time OT may be measured only during the period from the start-up to the shutdown of the power conversion device 100 when the semiconductor diode SD and the semiconductor switch SW are energized.

[0155] After completing the processing of step S112, CPU 141 proceeds to step S114.

[0156] It should be noted that the maximum temperature difference Ymax may be updated multiple times during operation of the power conversion device 100. In this case, when the power conversion device 100 stops operating, only the data corresponding to the most recent temperature difference Y for which the maximum temperature difference Ymax was updated is retained in RAM 142B; other data is not retained. Therefore, when the power conversion device 100 stops operating, the temperature difference Y data retained in RAM 142B is the data that is greater than the maximum temperature difference Ymax before the previous shutdown and corresponds to the maximum value of the temperature difference Y during the current operation.

[0157] In step S114, the CPU 141 sets a new data flag F1 (F1=SET) in the RAM 142A. This allows the CPU 141 to recognize later that data of a temperature difference Y greater than both the reference value Yth1 and the maximum temperature difference Ymax is stored in the RAM 142B (see below). Figure 5 Step S204).

[0158] After completing the process of step S114, the CPU 141 ends the process of this flowchart.

[0159] It should be noted that the processing order of steps S112 and S114 can be reversed, and it is an arbitrary order.

[0160] Thus, in this example, when the temperature difference Y between the heat sink temperature Tf and the indoor air temperature Ta exceeds both the reference value Yth1 and the maximum value of the previous temperature difference Y (maximum temperature difference Ymax) during operation of the power conversion device 100, the control device 140 can store the temperature difference Y in RAM 142B. Furthermore, the control device 140 can store the operating time OT, which corresponds to the operating time of the power conversion device 100 from the time the temperature difference Y corresponding to the previous maximum temperature difference Ymax was obtained until the current temperature difference Y (i.e., the new maximum temperature difference Ymax) was obtained, in RAM 142B.

[0161] Next, Figure 5 The flowchart is repeatedly executed in each predetermined control cycle during the operation of the power conversion device 100 , for example.

[0162] like Figure 5 As shown, in step S202, the CPU 141 determines whether the power conversion device 100 (control device 140) has been detected as powered off. If the CPU 141 has detected that the power conversion device 100 has been powered off, the process proceeds to step S204. If the CPU 141 has not detected that the power conversion device 100 has been powered off, the process of this flowchart ends.

[0163] It should be noted that in this example, the ring buffer RB includes a number of buffer memories B (buffer memory B(1) to buffer memory (RPmax)) equal to a specified value RPmax, which is an integer greater than or equal to 2. Furthermore, the ring buffer pointer RP indicates the data recording location in the plurality of buffer memories B (predetermined value RPmax) in the ring buffer RB, and its initial value is set to 1.

[0164] In step S204, the CPU 141 determines whether the new data flag F1 is set in the RAM 142A. If the new data flag F1 is set in the RAM 142A, the CPU 141 proceeds to step S206. If the new data flag F1 is not set, the CPU 141 ends the processing of this flowchart.

[0165] In step S206, the data of the operating time OT, temperature difference Y, heat sink temperature Tf, and indoor air temperature Ta stored in RAM 142B are recorded in the ring buffer RB of EEPROM 143B. Specifically, the data is recorded in B(RP) corresponding to the current value of the ring buffer pointer RP, among the predetermined number RPmax of buffer memories B between buffer memory B(1) and buffer memory B(RPmax) in the ring buffer RB.

[0166] After completing the processing of step S206, CPU 141 proceeds to step S208.

[0167] In step S208 , the CPU 141 clears (resets) the operating time OT. Thus, the operating time OT is counted starting from the next startup (power ON) of the power conversion device 100 , with the current temperature difference Y recorded as the starting point.

[0168] After completing the processing of step S208, CPU 141 proceeds to step S210.

[0169] In step S210, the CPU 141 advances the ring buffer pointer RP set in the EEPROM 143B by one pointer. Specifically, if the ring buffer pointer RP is less than the specified value RPmax, the ring buffer pointer RP is incremented by one pointer (RP = RP + 1). On the other hand, if the ring buffer pointer RP is at the specified value RPmax, the ring buffer pointer RP is returned to "1" (RP = 1). This allows the CPU 141 to record data next time into the buffer memory B located immediately after the buffer memory B in the ring buffer RB where the current data was recorded.

[0170] After completing the processing of step S210, CPU 141 proceeds to step S212.

[0171] In step S212, the CPU 141 sets the ring buffer flag F2 in the EEPROM 143B (F2 = SET). Thus, the CPU 141 can refer to the ring buffer flag F2 in the EEPROM 143B to recognize that data is recorded in the ring buffer RB.

[0172] After completing the processing of step S212, CPU 141 proceeds to step S214.

[0173] In step S214 , the CPU 141 clears the new data existence flag F1 of the RAM 142A.

[0174] After completing the processing of step S214, CPU 141 ends the processing of this flowchart.

[0175] It should be noted that the order of the processing of steps S208 to S214 can be changed appropriately and can be any order.

[0176] Thus, in this example, when the power conversion device 100 ends operation, the CPU 141 can record the maximum temperature difference Y during the current operation, which is greater than the previous maximum temperature difference Ymax, in the non-volatile ring buffer RB. Simultaneously, the CPU 141 can record the operating time OT, which corresponds to the operating time of the power conversion device 100 from the time the previous maximum temperature difference Ymax was recorded until the current temperature difference Y to be recorded, in the non-volatile ring buffer RB.

[0177] Next, Figure 6 For example, the process is executed when the operation of the power conversion device 100 is started (specifically, when the power supply of the control device 140 is turned on).

[0178] like Figure 6 As shown, in step S302, CPU 141 determines whether data is recorded in the ring buffer, that is, whether ring buffer flag F2 is set in EEPROM 143B. If ring buffer flag F2 is set, CPU 141 proceeds to step S304. If ring buffer flag F2 is not set, the processing of this flowchart ends.

[0179] In step S304 , the CPU 141 reads the ring buffer pointer RP from the EEPROM 143B.

[0180] After completing the processing of step S304, CPU 141 proceeds to step S306.

[0181] In step S306 , the CPU 141 reads the latest heat sink temperature Tf, indoor 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.

[0182] After completing the processing of step S306, CPU 141 proceeds to step S308.

[0183] In step S308 , the CPU 141 sets the read latest temperature difference Y as the maximum temperature difference Ymax in the RAM 142B.

[0184] After completing the process of step S308 , the CPU 141 ends the process of this flowchart.

[0185] 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 of 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 Figure 4 Step S108).

[0186] Next, Figure 7 The flowchart is executed at a specified time. For example, Figure 7 The flowchart can be executed when the operation of the power conversion device 100 is started (when the power of the control device 140 is turned on) or when the operation is stopped (when the power is turned off). Figure 7The flowchart can be used when the data of the temperature difference Y and the like in RAM 142B is updated during the operation of the power conversion device 100 (see Figure 4 In addition, for example, Figure 7 The flowchart can be configured to be manually executed based on user input. In this case, the user input can be received through an input unit provided in a predetermined machine electrically driven by the power conversion device 100 or the motor M, or the user input can be received from the terminal device 300 via a predetermined communication line.

[0187] like Figure 7 As 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. If the ring buffer flag F2 is set, the CPU 141 proceeds to step S404. If the ring buffer flag F2 is not set, the processing of this flowchart ends.

[0188] In step S404, CPU 141 determines whether the heat sink temperature Tf stored in RAM 142B is greater than a reference value Tf_th1. For example, through experiments or simulations, reference value Tf_th1 is previously determined as a lower limit for determining whether fin section 194 is clogged by foreign matter. Furthermore, reference value Tf_th1 is set to a value somewhat lower than reference value Tf_th2, which corresponds to a heat sink temperature Tf when heat sink section 194 becomes extremely high and the power converter 100 is forced to stop due to heating. This allows the determination of cooling anomalies in the power converter 100 before the power converter 100 is forced to stop. If heat sink temperature Tf is greater than reference value Tf_th1, CPU 141 proceeds to step S406; if it is less than reference value Tf_th1, CPU 141 proceeds to step S408.

[0189] In step S406 , the CPU 141 issues a warning to the user indicating that there is a possibility of clogging of the fin portion 194 (hereinafter referred to as “fin clogging warning”).

[0190] The heat sink blockage alarm can be reported to the user, for example, via display device 160. Display device 160 may display only the fact that the heat sink blockage alarm has been reported. Furthermore, in addition to the fact that the heat sink blockage alarm has been reported, display device 160 may also display data on the operating status (operating state) of the power conversion device 100, including data such as heat sink temperature Tf, indoor air temperature Ta, and temperature difference Y, as well as data indicating a history of these data, as numerical values. The data indicating the history may, for example, be data indicating changes in temperature difference Y.

[0191] Alternatively, the heat sink blockage alarm can be reported to the user via, for example, the terminal device 300. In this case, a signal corresponding to the heat sink blockage alarm output from the control device 140 (hereinafter referred to as the "alarm signal") is transmitted from the communication device 170 to the terminal device 300. Upon receiving the alarm signal, the terminal device 300 notifies the user of the heat sink blockage alarm via the display unit 310. Similar to the case of reporting the heat sink blockage alarm via the display unit 160, the terminal device 300 (display unit 310) can simply display the alarm or, alternatively, display numerical values ​​of data related to the operating status of the power conversion device 100.

[0192] After completing the processing of step S406, CPU 141 proceeds to step S420.

[0193] Meanwhile, in step S408, CPU 141 determines whether the indoor air temperature Ta stored in RAM 142B is greater than a reference value Ta_th1. For example, through experiments or simulations, a reference value Ta_th1 is predefined as a lower limit for determining whether the indoor air temperature of power conversion device 100 has deviated from a normal range. If the indoor air temperature Ta is greater than the reference value Ta_th1, CPU 141 proceeds to step S410; if it is less than the reference value Ta_th1, CPU 141 proceeds to step S412.

[0194] In step S410 , the CPU 141 notifies the user of both an alarm indicating abnormal indoor air temperature (hereinafter referred to as “indoor air abnormality alarm”) and a fin clogging alarm.

[0195] Similar to the heat sink blockage alarm, the abnormal internal air pressure alarm can be reported via the display device 160 or the terminal device 300 (display unit 310). Furthermore, similar to the heat sink blockage alarm, the display device 160 or the terminal device 300 (display unit 310) can display only the fact that the internal air pressure alarm has been reported, or it can also display numerical values ​​of data related to the operating status of the power conversion device 100.

[0196] After completing the processing of step S410, CPU 141 proceeds to step S420.

[0197] On the other hand, in 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 in which data is recorded among the buffer memories B(1) to B(RPmax) of the ring buffer RB, is a predetermined number (e.g., four) or more. If the number of data recorded in the ring buffer RB is the predetermined number or more, the CPU 141 proceeds to step S414. If the number of data recorded in the ring buffer RB is less than the predetermined number, the CPU 141 terminates the processing of this flowchart. This is because by using as much data as possible of the temperature difference Y to determine cooling anomalies, the possibility of erroneous determination of a clogging anomaly in the heat sink 194 can be suppressed.

[0198] In step S414, the CPU 141 approximately predicts the future temporal changes of the temperature difference Y based on the data of the temperature difference Y and the operating time OT recorded in the ring buffer RB, which exceeds a predetermined value. Specifically, the CPU 141 predicts the time TMest required for the temperature difference Y to reach the reference value Yth2 at which the power conversion device 100 is forced to stop.

[0199] For example, the CPU 141 can predict the future time variation of the temperature difference Y by linear approximation based on the history of the temperature difference Y and the operating time OT, thereby predicting the required time TMest. Alternatively, for example, the CPU 141 can predict the future time variation of the temperature difference Y by using a multivariate analysis method based on the temperature difference Y, the heat sink temperature Tf, the indoor air temperature Ta, and other data related to the operating state (operating state) of the power conversion device 100 other than the operating time OT, thereby predicting the required time TMest. In this case, at the time when the temperature difference Y and other data are stored in the RAM 142B (refer to Figure 4 Other data are also stored in RAM 142B and are stored in RAM 142B when the operation of the power conversion device 100 is stopped (see step S112). Figure 5 Other data may include, for example, 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.

[0200] After completing the processing of step S414, CPU 141 proceeds to step S416.

[0201] In step S416, CPU 141 determines whether required time TMest is shorter (less) than reference time TMth (an example of a first reference time). If required time TMest is shorter than reference time TMth, CPU 141 proceeds to step S418. If required time TMest is longer than reference time TMth, CPU 141 terminates the current flowchart.

[0202] In step S418, the CPU 141 notifies the user of a heat sink blockage alarm.

[0203] As described above, the heat sink clogging alarm can be reported to the user via the display device 160 or the terminal device 300. Furthermore, as described above, the display device 160 or the terminal device 300 (display unit 310) can display only the fact that the heat sink clogging alarm has occurred, or can also display data related to the operating status of the power conversion device 100 as numerical values.

[0204] After completing the processing of step S418, CPU 141 proceeds to step S420.

[0205] In step S420, CPU 141 determines whether the operating time TMfan of cooling fan 180 is greater than or equal to a reference value TMfan_th. The operating time TMfan of cooling fan 180 corresponds to the cumulative operating time since the cooling fan 180 was first delivered. Operating time TMfann can be obtained by accumulating operating time using a clock counter in CPU 141, starting from the factory shipment of power conversion device 100. Furthermore, it can be reset when cooling fan 180 is replaced. The reference value TMfan_th is predefined as the so-called lifespan or warranty period of cooling fan 180. If the operating time TMfan of cooling fan 180 is greater than or equal to the reference value TMfan_th, CPU 141 proceeds to step S422. If the operating time TMfan of cooling fan 180 is less than (shorter than) the reference value TMfan_th, the processing of this flowchart ends.

[0206] In step S422 , the CPU 141 notifies the user of an alarm indicating that there is a possibility of an abnormality in the cooling fan (hereinafter referred to as a “fan abnormality alarm”).

[0207] The fan abnormality alarm can be reported to the user via the display device 160, similar to the heat sink blockage alarm, or via the terminal device 300. Alternatively, the display device 160 or the terminal device 300 (display unit 310) can simply display the fact that the fan abnormality alarm has occurred. Furthermore, the display device 160 or the terminal device 300 (display unit 310) can also display data related to the operating status of the power conversion device 100 (e.g., the value of the operating time TMfan, which corresponds to the cumulative operating time of the cooling fan 180) along with the fan abnormality alarm.

[0208] After completing the processing of step S422, CPU 141 ends the processing of this flowchart.

[0209] Thus, in this example, the control device 140 determines whether the heat sink 194 is clogged based on the increasing trend of the temperature difference Y. Specifically, the control device 140 predicts the temporal changes in the temperature difference Y based on the past history of the temperature difference Y stored in the ring buffer RB, thereby determining the required time TMest until the temperature difference Y reaches the reference value Yth2. Furthermore, if the control device 140 determines that the required time TMest is shorter than the reference time TMth, that is, if the temperature difference Y exceeds the reference value Yth2 and the power conversion device 100 is about to be forced to stop, the control device 140 issues a heat sink clog alarm to the user. This allows the control device 140 to urge the user to clean the heat sink 194, for example, before the temperature difference Y exceeds the reference value Yth2 and the power conversion device 100 is forced to stop.

[0210] Furthermore, as clogging of the fins 194 progresses, it may become difficult to coordinate the operation timing of a predetermined machine driven by the motor M and the maintenance timing for cleaning the fins 194 .

[0211] In contrast, in this example, by appropriately adjusting the required time TMest, the control device 140 can notify the user of a heat sink blockage alarm before the blockage abnormality progresses to the point where the power conversion device 100 is forced to stop. Consequently, the user can receive notification of the heat sink blockage alarm and adjust the timing for operating or maintaining a specific machine electrically driven by the motor M.

[0212] Furthermore, in this example, the CPU 141 issues a heat sink blockage warning to the user when the heat sink temperature Tf exceeds a reference value Tf_th1, which 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. This allows the control device 140 to urge the user to clean the heat sink 194, for example, before the power conversion device 100 is forced to stop due to the heat sink temperature Tf exceeding the reference value Tf_th2.

[0213] Furthermore, in this example, CPU 141 notifies the user of an abnormal indoor air temperature alarm and a fin blockage alarm when the indoor air temperature Ta exceeds a reference value Ta_th1. This prompts the user to perform various maintenance procedures to suppress increases in indoor air temperature, including cleaning to eliminate blockage in fin section 194, when the indoor air temperature rises above a normal range.

[0214] Next, Figure 8 The flowchart is repeatedly executed every predetermined control cycle during the operation of the power conversion device 100 .

[0215] like Figure 8 As shown, in step S502, CPU 141 determines whether data is recorded in ring buffer RB, that is, whether ring buffer flag F2 is set in RAM 142A. If ring buffer flag F2 is set, CPU 141 proceeds to step S504. If ring buffer flag F2 is not set, the processing of this flowchart ends.

[0216] In step S504, the CPU 141 determines whether the operating time OT is longer than the reference time OTth (an example of the second reference time). If the operating time OT is longer than the reference time OTth, the CPU 141 proceeds to step S506. If the operating time OT is shorter than the reference time OTth, the CPU 141 ends the processing of this flowchart.

[0217] In step S506, the CPU 141 determines whether the ring buffer pointer RP is the head pointer RPtop. The head pointer RPtop corresponds to the number of the buffer memory B in which the oldest data is recorded among the buffer memories B(1) to B(RPmax) of the ring buffer RB. The initial value of the head pointer RPtop is "1". If data is recorded in all of the buffer memories B(1) to B(RPmax) and the latest data is recorded in the buffer memory B(1), the head pointer RPtop moves to "2". And, thereafter, the head pointer RPtop moves forward one position each time the latest data is recorded. If the ring buffer pointer RP is the head pointer RPtop, the CPU 141 proceeds to step S508. If the head pointer is not RPtop, the CPU 141 proceeds to step S510.

[0218] In step S508 , the CPU 141 clears the ring buffer pointer RP and the ring buffer flag F2 of the EEPROM 143B.

[0219] After completing the processing of step S508, CPU 141 proceeds to step S512.

[0220] Meanwhile, in step S510, CPU 141 increments the ring buffer pointer RP by one. For example, if the ring buffer pointer RP is not 1, the value of the ring buffer pointer RP is decremented by one (RP = RP - 1). Alternatively, if the ring buffer pointer RP is 1, the ring buffer pointer RP is set to RPmax (RP = RPmax).

[0221] After completing the processing of step S510, CPU 141 proceeds to step S512.

[0222] In step S512, the CPU 141 clears the operating time OT, thereby restarting the counting of the operating time OT from zero.

[0223] After completing the processing of step S512, CPU 141 ends the processing of this flowchart.

[0224] Thus, 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 resets the ring buffer pointer RP to one, assuming that the latest data no longer exists. This can prevent the occurrence of erroneous cooling anomalies based on the latest data, for example, by cleaning the heat sink 194 and the air intake of the power conversion device 100 housing after acquiring the latest data, eliminating the tendency for the temperature difference Y to increase.

[0225] Furthermore, in this example, control device 140 can retain data older than the most recent data in ring buffer RB. This allows, for example, if heat sink 194 or the air intake port of the power converter 100 housing is cleaned but insufficiently, causing the temperature difference Y to immediately increase, to use not only the newly recorded data but also the retained data. Therefore, even if the increase in temperature difference Y reappears after a simple cleaning, control device 140 can detect the presence of a blockage abnormality in heat sink 194 at an earlier stage.

[0226] Furthermore, in this example, the control device 140 clears the operating time OT after returning the ring buffer RB to one position. This allows the control device 140 to return the ring buffer pointer RP to one position each time a reference time OTth elapses, after the latest data has been recorded in the ring buffer RB, while maintaining a state where no new data is recorded. Furthermore, if the ring buffer pointer RP returns to the top pointer RPtop and no new data is recorded while the reference time OTth elapses, the control device 140 can also assume that no data exists in the ring buffer RB. Therefore, for example, if the increasing trend in the temperature difference Y is completely eliminated by cleaning the heat sink 194 or the air intake port of the power conversion device 100 housing, the control device 140 can prevent the use of older data and the resulting misjudgment of a cooling anomaly.

[0227] <Specific Example of Cooling Abnormality Determination Operation>

[0228] Figure 9 1 is a diagram for explaining an example of an operation related to the determination of cooling abnormality by the control device 140. Specifically, Figure 9 The diagram shows data Tf_N1 , Tf_N2 , Tf_N3 , and Tf_N4 of the heat sink temperature Tf and data Y_N1 , Y_N2 , Y_N3 , and Y_N4 of the temperature difference Y recorded in the ring buffer RB by the control device 140 in chronological order. Figure 9 The graph 910 shows data Tf_N1 , Tf_N2 , Tf_N3 , and Tf_N4 of the heat sink temperature Tf in chronological order, and the graph 920 shows data Y_N1 , Y_N2 , Y_N3 , and Y_N4 of the temperature difference Y in chronological order.

[0229] It should be noted that data Tf_N1 and data Y_N1, data Tf_N2 and data Y_N2, data Tf_N3 and data Y_N3, and data Tf_N4 and data Y_N4 are data recorded in the ring buffer RB at the same time. Figure 11 The same is true for .

[0230] like Figure 9 As shown, when the temperature difference Y is less than 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 abnormal blockage of the heat sink 194, and new data (in this example, data Y_N1, Tf_N1) is recorded in the ring buffer RB (refer to Figure 4 ). And, every time the current temperature difference Y exceeds the maximum value of the recorded past temperature difference Y (maximum temperature difference Ymax), the new data (in this case, data Tf_N2, Y_N2, etc.) is recorded in the ring buffer RB in sequence (refer to Figure 4 ). As a result, the history data of the temperature difference Y indicating the increasing trend of the temperature difference Y is accumulated in the ring buffer RB.

[0231] In this example, after data Y_N4 and Tf_N4 are recorded, control device 140 uses linear approximation to predict the temporal variation of temperature difference Y based on data Y_N1, Y_N2, Y_N3, and Y_N4. Specifically, control device 140 calculates an approximate line L1 for temporal variation and calculates required time TMest from the intersection of approximate line L1 and a line corresponding to reference value Yth2. Control device 140 then determines that the calculated required time TMest is shorter than reference time TMth. Consequently, control device 140 can issue a fin blockage alarm, prompting the user to clean the fin section 194, for example.

[0232] Furthermore, before acquiring data Y_N4 and Tf_N4, the data on heat sink temperature Tf (in this example, data Tf_N3a) may exceed reference value Tf_th1. In this case, control device 140 also issues a heat sink clogging alarm. Therefore, even when the rising trend in heat sink temperature Tf is more pronounced than the increasing trend in temperature difference Y, control device 140 can appropriately inform the user of the possibility of abnormal clogging of heat sink fins 194 and urge the user to clean the clogging.

[0233] Furthermore, before data Y_N4 and Tf_N4 are acquired, the heat sink 194, the air intake port of the power conversion device 100 housing, and so on may be cleaned. For example, if cleaning is performed after data Y_N2 and Tf_N2 are recorded, the increasing trend of the temperature difference Y is eliminated. Even if the reference time OTth has passed, data Y_N3b cannot exceed data Y_N2, and new data is not recorded. In this case, the control device 140 returns the ring buffer pointer RP by one position, assuming that the latest data Y_N2 does not exist. Therefore, the control device 140 uses the latest data Y_N2 to prevent misjudgment of an increasing trend of the temperature difference Y, thereby preventing misjudgment of a blockage abnormality in the heat sink 194.

[0234] [Another Example of Operation Related to Determination of Cooling Abnormality in Power Converter]

[0235] Next, refer to Figure 10 、 Figure 11 , another example of the operation related to the determination of cooling abnormality of the power conversion device 100 is described.

[0236] The following description focuses on the parts that are different from the above example, and the description of the same or corresponding content may be simplified or omitted.

[0237] <Control Processing Related to Determination of Cooling Abnormality>

[0238] Figure 10 1 is a diagram showing another example of control processing related to the determination of cooling abnormality. Specifically, Figure 10 A flowchart schematically shows another example of the data acquisition process related to the determination of cooling abnormality.

[0239] In this example, the termination process related to the determination of cooling abnormality, the start-up process related to the determination of cooling abnormality, the determination process of cooling abnormality, and the determination process of cooling abnormality alleviation are similar to those in the above example ( Figures 5 to 8 ) are the same, so the description is omitted.

[0240] Figure 10 The flowchart in the above example (with Figure 4 For example, during the operation of the power conversion device 100, that is, from the start of operation (power ON of the control device 140) to the stop of operation (power OFF of the control device 140), it is repeatedly executed in each prescribed control cycle.

[0241] like Figure 10 As shown, the processing of steps S602 and S604 is the same as Figure 4 Steps S102 and S104 are the same, so their description is omitted.

[0242] After the CPU 141 finishes the processing of step S604, it proceeds to step S606.

[0243] In step S606, 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. 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.

[0244] 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.

[0245] On the other hand, the processing of steps S610 to S614 is the same as Figure 4 steps S106 to S110 of

[0246] After the CPU 141 finishes the processing of step S614, it proceeds to step S616.

[0247] The processing of steps S616 and S618 is the same as Figure 4 steps S112 and S114 of

[0248] After the CPU 141 finishes the processing of step S618, the processing of the current flowchart ends.

[0249] Thus, in this example, when no data is 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 in a situation where the temperature difference Y sharply exceeds the reference value Yth1 due to some reason different from the blockage of the heat sink unit 194 is obtained, and thus a situation of misjudgment of 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 obtain 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 and initially obtain data in the range exceeding the reference value Yth1.

[0250] <Specific example of the cooling abnormality determination operation>

[0251] Figure 11 1 is a diagram for explaining another example of the operation related to the determination of cooling abnormality by the control device 140. Specifically, Figure 11 The diagram shows data Tf_N0, Tf_N1, Tf_N2, Tf_N3, and Tf_N4 of the heat sink temperature Tf and data Y_N0, Y_N1, Y_N2, Y_N3, and Y_N4 of the temperature difference Y recorded in the ring buffer RB by the control device 140 in chronological order. Figure 11 The graph 1110 includes data Tf_N0, Tf_N1, Tf_N2, Tf_N3, and Tf_N4 showing the heat sink temperature Tf in chronological order, and a graph 1120 including data Y_N0, Y_N1, Y_N2, Y_N3, and Y_N4 showing the temperature difference Y in chronological order.

[0252] Figure 11 In addition to the additional data Tf_N0, Y_N0, the same as the above example ( Figure 9 ) is the same as the above example. Figure 9 )The explanation focuses on different parts.

[0253] It should be noted that data Tf_N0 and data Y_N0 are data recorded in the ring buffer RB at the same time.

[0254] like Figure 11 As shown, in this example, the same as the above example ( Figure 9 ), data Y_N0 and Tf_N0 indicating that the temperature difference Y is greater than the reference value Yth0 and falls within the range of the reference value Yth1 are initially recorded in the ring buffer RB. Subsequently, data Y_N1 and Tf_N1 indicating that the temperature difference Y exceeds the reference value Yth1 are recorded in the ring buffer RB. This prevents data from being recorded in the ring buffer RB indicating that the temperature difference Y exceeds the reference value Yth1, for example, due to a sudden increase in the temperature difference Y for reasons other than a blockage abnormality in the heat sink 194. This prevents the control device 140 from misjudging the heat sink 194 blockage abnormality by utilizing such data.

[0255] [Another Example of Operation Related to Determination of Cooling Abnormality in Power Converter]

[0256] Next, refer to Figure 12 , another example of the operation related to the determination of cooling abnormality of the power conversion device 100 is described.

[0257] The following description focuses on the parts that are different from the above example, and the description of the same or corresponding content may be simplified or omitted.

[0258] Figure 12 1 is a diagram showing another example of control processing related to the determination of cooling abnormality. Specifically, Figure 12 This is a flowchart schematically showing another example of the cooling abnormality determination process.

[0259] In the above example, the control device 140 determines whether the power conversion device 100 is experiencing a cooling anomaly based on the temporal change in the increase in the temperature difference Y. However, the determination of the presence of a cooling anomaly in the power conversion device 100 can be made more simply based on the temperature difference Y. Specifically, the control device 140 can determine that a cooling anomaly exists in the heat sink 194 when the temperature difference Y becomes relatively high (for example, when the temperature difference Y exceeds a reference value Yth1 or a predetermined reference value set between the reference values ​​Yth1 and Yth2). This is described in detail below.

[0260] like Figure 12 As shown, steps S702, S704 and Figure 4 The processing of steps S102 and S104 is the same, so the description is omitted.

[0261] After completing the processing of step S704, the control device 140 proceeds to step S706.

[0262] In step S706, CPU 141 determines whether the temperature difference Y calculated in step S104 exceeds a reference value Yth1. If the temperature difference Y exceeds the reference value Yth1, CPU 141 determines that there is an abnormality in cooling structure 190 (radiating fins 194) and proceeds to step S708. If the temperature difference Y does not exceed the reference value Yth1, the processing in this flowchart ends.

[0263] In step S708 , the CPU 141 notifies the user of a heat sink blockage alarm.

[0264] After completing the processing of step S708, the control device 140 ends the processing of this flowchart.

[0265] It should be noted that, in this example, the control processing related to the determination of cooling abnormality is integrated into Figure 12 The flowchart does not include the data acquisition process related to the cooling abnormality determination, the termination process related to the cooling abnormality determination, and the startup process related to the cooling abnormality determination, as in the above example. Therefore, in this example, EEPROM 143B and ring buffer RB can be omitted.

[0266] Thus, in this example, control device 140 can determine the presence of cooling anomalies in cooling structure 190 (radiating fins 194) simply by using a relatively high temperature difference Y as a trigger. Therefore, control device 140 can determine cooling anomalies in cooling structure 190 using a relatively simple configuration.

[0267] [Another embodiment]

[0268] Next, another embodiment will be described.

[0269] The contents of the above-described embodiment can be modified and altered as appropriate.

[0270] 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. Furthermore, 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. Thus, the control device 140 can improve the accuracy of the determination related to the cooling abnormality, thereby making it possible to make a more appropriate determination related to the cooling abnormality. Specifically, when the control device 140 approximately predicts the time change of the temperature difference Y (required time TMest) (refer to Figure 7 In step S414), only the data of the temperature difference Y other than the singular value can be used. Thus, the control device 140 can improve the prediction accuracy of the required time TMest.

[0271] In addition, for example, in the above embodiment ( Figure 8 ), if the time longer than the reference time OTth has passed since the latest data was recorded in the ring buffer RB, the ring buffer pointer RP returns one bit, but B(RP) of the ring buffer RB can be deleted at the same time.

[0272] Furthermore, for example, in the above-described embodiment, the power conversion device 100 (control device 140) can manually delete all ring buffer RB data based on user input. This allows the user to automatically delete the ring buffer RB data, for example, when cleaning the heat sink 194 or the air intake vents of the power conversion device 100 housing. In this case, user input can be received via an input unit provided in a predetermined machine electrically driven by the power conversion device 100 or the motor M, or via a terminal device 300 communicatively connected to the power conversion device 100.

[0273] Furthermore, for example, in the above-described embodiment, the power conversion device 100 (control device 140) can be configured to automatically delete all data in the ring buffer RB when the possibility of a cooling anomaly has been eliminated. For example, if the operating time OT after the latest data is recorded in the ring buffer RB remains unchanged for a period exceeding a predetermined threshold, the control device 140 can determine that the heat sink 194 has been cleaned and the possibility of a cooling anomaly has been eliminated. The predetermined threshold can be predetermined, for example, within a range greater than a reference time OTth. Furthermore, the control device 140 can determine that the possibility of a cooling anomaly has been eliminated when the temperature difference Y remains below a reference value Yth1 from the start of the current operation of the power conversion device 100 (power on) to the stop of operation (power off). In this case, the control device 140 can delete all data in the ring buffer RB when the possibility of a cooling anomaly has been determined to have been eliminated (i.e., when the power conversion device 100 stops operating) or when the next operation is restarted.

[0274] Furthermore, for example, in the above embodiment, data used to determine cooling anomalies, including the temperature difference Y and the operating time OT, is recorded internally within the power conversion device 100. However, this data may also be recorded in a device external to the power conversion device 100. Examples of the external device include the computing device 200 and the terminal device 300 (each an example of a third external device). In this case, the control device 140 transmits data related to the temperature difference Y and data related to the operating mode of the power conversion device 100 to the external device, where the data is accumulated. Data related to the operating mode of the power conversion device 100 includes, for example, data indicating the times of operation start and stop, and data related to communication timings of the semiconductor diode SD and the semiconductor switch SW. Furthermore, the control device 140 can download and utilize the accumulated data from the external device to determine the presence of cooling anomalies using the same method as described above.

[0275] In addition, for example, in the above embodiment, part or all of the functions of the control device 140 can be transferred to an external device of the power conversion device 100, such as the computing device 200, the terminal device 300 (also an example of a cooling abnormality determination device), etc.

[0276] [effect]

[0277] Next, the operation of the power conversion device 100 (control device 140 ) according to this embodiment will be described.

[0278] In this embodiment, the power conversion device 100 includes power devices, a cooling structure 190, a cooling fan 180, and a control device 140. Specifically, the power devices include a semiconductor diode SD and a semiconductor switch SW. The cooling structure 190 is provided to dissipate heat from the power devices. The cooling fan 180 also blows air into the cooling structure 190. The control device 140 determines whether the cooling performance of the cooling structure 190 is abnormal based on the temperature difference Y between the temperature of the cooling structure 190 (heat sink 194) (heat sink temperature Tf) and the temperature inside the power conversion device 100 (housing) (indoor air temperature Ta).

[0279] Thus, the control device 140 focuses on the fact that the temperature difference Y becomes relatively large due to clogging of the heat sink portion 194 or the like, and can appropriately determine whether or not there is a cooling abnormality in the cooling structure 190 .

[0280] Alternatively, as in Patent Document 1, it is possible to determine cooling anomalies using the temperature of a specific portion of the power conversion device 100 itself. However, since changes in the measured temperature may be influenced by fluctuations in the load state of the power conversion device, the accuracy of determining cooling anomalies of the heat sink may be reduced.

[0281] In contrast, in this embodiment, the control device 140 does not use the temperature of the specified part of the power conversion device 100 itself, but instead uses the difference in temperature between two parts inside the power conversion device 100 (temperature difference Y), thereby suppressing the influence of the load state of the power conversion device 100 and enabling more appropriate judgments related to cooling abnormalities.

[0282] Alternatively, as in Patent Document 2, it is also possible to use the load status of the power converter in addition to the heat sink temperature and the temperature inside the power converter to determine cooling anomalies. In this case, by taking into account the load status of the power converter, it is expected that the accuracy of the determination will be improved. However, methods that use the heat sink temperature and the temperature inside the power converter separately, as in Patent Document 2, require the occurrence of a heating anomaly that would force the power converter to shut down. As mentioned above, this is because blockage anomalies such as those caused by heat sinks are relatively mild. Therefore, even if the influence of the power converter's load status is taken into account, it is difficult to detect cooling anomalies using the heat sink temperature and the temperature inside the power converter separately.

[0283] In contrast, in this embodiment, the control device 140 can more appropriately (earlier) determine whether there is a cooling abnormality before reaching a state where the power conversion device 100 must be forced to stop, by, for example, detecting a phenomenon in which the temperature difference Y becomes relatively large.

[0284] In addition, in the present embodiment, the control device 140 can make a determination regarding cooling abnormality based on the temporal change in the increase of the temperature difference Y.

[0285] Thus, the control device 140 can suppress the possibility of misjudging a situation where, for example, the temperature difference Y becomes relatively large due to a reason different from that of the cooling structure 190 as a cooling abnormality of the cooling structure 190.

[0286] Furthermore, in the present embodiment, the control device 140 may determine that a cooling abnormality exists when the temperature difference Y exceeds a reference value Yth1.

[0287] Thus, by appropriately setting the reference value Yth1, the control device 140 can specifically determine whether or not there is a cooling abnormality in the cooling structure 190.

[0288] In addition, in this 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 predetermined load state, and determine whether there is a cooling abnormality based on the corrected temperature difference Y.

[0289] Thus, the control device 140 suppresses the influence of the load state of the power device on the temperature difference Y, and can more appropriately perform the determination regarding the cooling abnormality of the cooling structure 190.

[0290] Furthermore, in this 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 predetermined load state based on the temperature of the power device (for example, the measured value of the junction temperature Tj).

[0291] Thus, the control device 140 can specifically suppress the influence of the load state of the power device on the temperature difference Y.

[0292] In addition, in this 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 predetermined load state based on the load current IL (measured value) output by the power conversion device 100.

[0293] Thus, the control device 140 can specifically suppress the influence of the load state of the power device on the temperature difference Y.

[0294] Furthermore, this embodiment includes an EEPROM 143B. Specifically, if the maximum value of the temperature difference Y (maximum temperature difference Ymax) is updated during the current operation of the power conversion device 100, the EEPROM 143B can store the maximum value of the temperature difference Y during the current operation of the power conversion device 100 when the power conversion device 100 is stopped (power off). Furthermore, when the power conversion device 100 is started, the control device 140 can obtain the maximum value of the temperature difference Y from the EEPROM 143B until the previous stop of operation. By comparing the temperature difference Y during the operation of the power conversion device 100 with the obtained maximum value of the temperature difference Y (maximum temperature difference Ymax), the control device 140 can detect the temporal change in the increase of the temperature difference Y.

[0295] Thus, the control device 140 can specifically grasp the increasing trend of the temperature difference Y.

[0296] Furthermore, in this embodiment, if a temperature difference Y exceeding the maximum value of the temperature difference Y (maximum temperature difference Ymax) occurs between the start and stop of operation of the power conversion device 100, the EEPROM 143B can accumulate and store the maximum value of the temperature difference Y between the start and stop of the current operation when the power conversion device 100 stops. Furthermore, based on the update history of the maximum value of the temperature difference Y stored in the EEPROM 143B (ring buffer RB), the control device 140 can predict the time required for the temperature difference Y to reach the reference value Yth2 (required time TMest). Furthermore, if the required time TMest is less than the reference time TMth, the control device 140 can determine that a cooling abnormality has occurred.

[0297] Thus, the control device 140 can specifically determine the presence or absence of cooling abnormality based on the increasing trend of the temperature difference Y.

[0298] In addition, in this embodiment, the control device 140 can use multivariate analysis to predict the required time TMest based on other information related to the operating 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.

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

[0300] In addition, in this 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.

[0301] Thereby, the control device 140 can improve the prediction accuracy of the required time TMest.

[0302] In addition, in the present embodiment, the control device 140 may predict the required time TMest by considering only the time during which the power devices are energized during the operation time of the power conversion device 100 .

[0303] Thus, the control device 140 can improve the prediction accuracy of the required time TMest.

[0304] In addition, in this embodiment, since the latest maximum value of the temperature difference Y is stored in EEPROM143B (ring buffer RB), the state in which the new maximum value of the temperature difference Y is not stored can be set to a state in which the new historical record of the (updated) historical record of the maximum value of the temperature difference Y stored in EEPROM143B can be sequentially overwritten or deleted every time the reference time OTth passes.

[0305] Thus, control device 140 can be configured to not utilize the most recent temperature difference Y data, for example, if the increasing trend of temperature difference Y has been resolved by cleaning heat sink 194. This prevents the most recent temperature difference Y data from being utilized, leading to an erroneous determination of cooling anomalies. Furthermore, since control device 140 is configured to utilize temperature difference Y data piece by piece, even if the cleaning process is minimal and the increasing trend of temperature difference Y re-emerges, it can utilize the remaining data to appropriately determine cooling anomalies.

[0306] In addition, in the present embodiment, the control device 140 may determine the passage of the reference time OTth by considering only the time during which the power device is energized during the operation time of the power conversion device 100 .

[0307] Thus, the control device 140 can more appropriately determine whether the increasing trend of the temperature difference Y has been eliminated.

[0308] In addition, in this embodiment, the EEPROM 143B may store the maximum value of the temperature difference Y when the temperature difference Y exceeds the reference value Yth1.

[0309] Thus, EEPROM 143B can store only the data of the temperature difference Y (maximum value) at a level corresponding to a state where the degree of cooling abnormality is relatively high to a certain extent.

[0310] In this embodiment, EEPROM 143B can store temperature difference Y (maximum value history) when temperature difference Y exceeds reference value Yth0, which is smaller than reference value Yth1. Furthermore, control device 140 can determine that an abnormality exists when temperature difference Y (maximum value history) greater than reference value Yth1 is stored in EEPROM 143B and temperature difference Y (maximum value history) less than reference value Yth1 previously stored is also stored.

[0311] Thus, the control device 140 can prevent a situation in which a cooling abnormality in the cooling structure 190 is erroneously determined to exist, for example, when the temperature difference Y increases rapidly due to a reason different from the cooling abnormality in the cooling structure 190 .

[0312] In addition, in this embodiment, under the control of the control device 140, when the possibility of an abnormality is eliminated, EEPROM143B can automatically or manually delete all temperature differences Y (update history of the maximum value) stored in the ring buffer RB based on the received specified input.

[0313] Thus, the control device 140 can automatically or manually delete the data of the temperature difference Y (history record of the maximum value) of the ring buffer RB when the heat sink portion 194 is cleaned and the increasing trend of the temperature difference Y is completely eliminated.

[0314] In the present embodiment, the reference value Yth1 may be defined based on the temperature difference Y when the cooling performance of the cooling structure 190 is in a predetermined normal state and the temperature difference Y when the cooling fan 180 is stopped.

[0315] Thus, the control device 140 can specifically define the reference value Yth1 for making a determination regarding cooling abnormality.

[0316] In addition, in this embodiment, the power conversion device 100 may include a display device 160 and a communication device 170, which are used to notify the user of the abnormality when the control device 140 determines that an abnormality exists.

[0317] Thus, the power conversion device 100 can notify the user of abnormal cooling of the cooling structure 190 through the display device 160 and the communication device 170.

[0318] In addition, in this embodiment, the power conversion device 100 (control device 140) can transmit data related to the operating state of the power conversion device 100 including data related to cooling abnormalities to the terminal device 300 and display it on the display unit 310 of the terminal device 300.

[0319] Thus, the power conversion device 100 can provide information related to cooling abnormalities to the user through the external terminal device 300.

[0320] Furthermore, in this 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 abnormalities.

[0321] Thus, the power conversion device 100 can visually provide the user with information related to cooling abnormalities through the display device 160.

[0322] Furthermore, in the present embodiment, the power conversion device 100 (control device 140 ) may display information related to cooling abnormality as numerical values ​​on the display device 160 .

[0323] Thus, the power conversion device 100 (control device 140 ) can provide the user with information related to cooling abnormalities more appropriately.

[0324] Furthermore, in the present embodiment, the power conversion device 100 (control device 140 ) may cause the calculation device 200 to execute calculation processing related to determination of cooling abnormality.

[0325] Thus, the power conversion device 100 (control device 140) can reduce the processing load related to the determination of cooling abnormality, thereby preventing the process related to the determination of cooling abnormality from affecting the control process of the inverter circuit 130, etc.

[0326] In addition, in this embodiment, the control device 140 can accumulate data related to the temperature difference Y and data related to the operation mode of the power conversion device 100 in the computing device 200, the terminal device 300, etc. Furthermore, the control device 140 can make a determination regarding cooling abnormalities based on the data accumulated in the computing device 200, the terminal device 300, etc.

[0327] Thus, the control device 140 can externally process the accumulated data simply by appropriately uploading the data used for determining cooling abnormality.

[0328] Although the embodiments have been described in detail above, the present invention is not limited to the specific embodiments, and various modifications and changes can be made within the scope of the gist described in the claims.

Claims

1. A power conversion device comprising: Power devices; A cooling structure for dissipating heat from the power device; an air supply unit for supplying air to the cooling structure; and a determination unit that determines whether the cooling performance of the cooling structure is abnormal based on a temperature difference between the temperature of the cooling structure and the temperature of air inside the power conversion device; The determination unit corrects the measured value of the temperature difference to the temperature difference when the power device is in a predetermined load state, and performs determination regarding the abnormality based on the corrected temperature difference.

2. The power conversion device according to claim 1, wherein: The determination unit makes a determination regarding the abnormality based on a temporal change in the increase of the temperature difference.

3. The power conversion device according to claim 1 or 2, wherein: The determination unit determines that the abnormality exists when the temperature difference exceeds a predetermined first reference value.

4. The power conversion device according to claim 1 or 2, wherein: The determination unit corrects the measured value of the temperature difference to the temperature difference when the power device is in the predetermined load state based on the temperature of the power device.

5. The power conversion device according to claim 1 or 2, wherein: The determination unit corrects the measured value of the temperature difference to the temperature difference when the power device is in the predetermined load state based on the load current output by the power conversion device.

6. The power conversion device according to claim 2, wherein: Also includes a non-volatile storage unit, The storage unit stores the maximum value of the temperature difference during the current operation of the power conversion device when the power supply of the power conversion device is turned off, until the maximum value of the temperature difference during the current operation of the power conversion device is updated. The determination unit obtains the maximum value of the temperature difference from the storage unit when the operation of the power conversion device is started until the last operation is stopped, and grasps the time change of the increase of the temperature difference by comparing the temperature difference during the operation of the power conversion device with the obtained maximum value of the temperature difference.

7. The power conversion device according to claim 6, wherein: When the temperature difference exceeding the maximum value of the temperature difference until the last power-off occurs between power-on and power-off of the power conversion device, the storage unit accumulates and stores the maximum value of the temperature difference between the current power-on and power-off when the power conversion device is turned off. The determination unit predicts the time required for the temperature difference to reach a specified second reference value based on the update history of the maximum value of the temperature difference stored in the storage unit, and determines that the abnormality exists when the predicted required time is shorter than the specified first reference time.

8. The power conversion device according to claim 7, wherein: The determination unit predicts the required time using multivariate analysis based on not only the update history of the maximum value of the temperature difference stored in the storage unit but also other information related to the operating state of the power conversion device.

9. The power conversion device according to claim 7 or 8, wherein: The determination unit extracts a singular value from the update history of the maximum value of the temperature difference stored in the storage unit, and predicts the required time based on the update history of the maximum value of the temperature difference other than the singular value.

10. The power conversion device according to claim 7 or 8, wherein: The determination unit estimates the required time by considering only the time during which the power device is energized during the operation time of the power conversion apparatus.

11. The power conversion device according to claim 7 or 8, wherein: After the latest maximum value of the temperature difference is stored in the storage unit, the state in which no new maximum value of the temperature difference is stored is set to a state in which the historical records of the maximum value of the temperature difference stored in the storage unit can be sequentially overwritten or deleted starting from the new historical records.

12. The power conversion device according to claim 11, wherein: The determination unit determines the passage of the second reference time by considering only the time during which the power device is energized during the operation time of the power conversion apparatus.

13. The power conversion device according to any one of claims 6 to 8, wherein: The storage unit stores the maximum value of the temperature difference when the temperature difference exceeds a predetermined first reference value.

14. The power conversion device according to claim 13, wherein: The storage unit stores the maximum value of the temperature difference when the temperature difference exceeds a predetermined third reference value which is smaller than the first reference value. The determination unit determines that the abnormality exists when the maximum value of the temperature difference greater than the first reference value is stored in the storage unit and the maximum value of the temperature difference less than the first reference value stored previously is stored.

15. The power conversion device according to any one of claims 6 to 8, wherein: The storage unit automatically deletes all the stored maximum values ​​of the temperature differences when the possibility of the abnormality is eliminated, or manually deletes all the stored maximum values ​​of the temperature differences based on the received specified input.

16. The power conversion device according to claim 3, wherein: The first reference value is determined based on the temperature difference when the cooling performance is in a predetermined normal state and the temperature difference when the air blower is stopped.

17. The power conversion device according to any one of claims 1, 2, and 6 to 8, wherein: It also includes a notification unit, which is used to notify the user about the abnormality when the determination unit determines that the abnormality exists.

18. The power conversion device according to any one of claims 1, 2, and 6 to 8, wherein: Data related to the operating state of the power conversion device, including data related to the abnormality, is sent to a first external device, and is displayed on a display unit of the first external device.

19. The power conversion device according to any one of claims 1, 2, and 6 to 8, wherein: The device further includes a display unit for displaying information related to the operating state of the power conversion device, including information related to the above-mentioned abnormality.

20. The power conversion device according to claim 18, wherein: The display unit is caused to display information related to the abnormality as numerical values.

21. The power conversion device according to any one of claims 1, 2, and 6 to 8, wherein: The second external device is caused to execute a calculation process related to the determination of the abnormality.

22. The power conversion device according to any one of claims 1, 2, and 6 to 8, wherein: The determination unit causes a third external device to accumulate data related to the temperature difference and data related to an operation mode of the power conversion device, and makes a determination related to the abnormality based on the data accumulated in the third external device.

23. A cooling anomaly determination device for a power conversion device, the power conversion device comprising: Power devices; A cooling structure for dissipating heat from the power device; and The air supply unit is used to supply air to the cooling structure. The cooling abnormality determination device corrects the measured value of the temperature difference between the temperature of the above-mentioned cooling structure and the temperature of the air inside the power conversion device to the above-mentioned temperature difference when the above-mentioned power device is in a specified load state, and based on the above-mentioned corrected temperature difference, makes a determination related to the abnormality of the cooling performance of the above-mentioned cooling structure.

24. A method for determining cooling anomaly of a power conversion device, the method comprising: Power devices; A cooling structure provided with a plurality of heat sinks for dissipating heat from the power device; and The air supply unit is used to supply air to the cooling structure. The cooling abnormality determination method corrects the measured value of the temperature difference between the temperature of the above-mentioned cooling structure and the temperature of the air inside the power conversion device to the above-mentioned temperature difference when the above-mentioned power device is in a specified load state, and based on the above-mentioned corrected temperature difference, makes a determination related to the abnormality of the cooling performance of the above-mentioned cooling structure.

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