Power Conversion Equipment

Abstract

To accurately determine whether a cooling fan fails or freezes.SOLUTION: In a housing, a fan (24) cools a power inverter circuit (21). A revolution number sensor (26) measures the revolution number of the fan (24). A temperature sensor (23) measures a temperature inside the housing. A control part (22) obtains the revolution number of the fan (24) from the revolution number sensor (26) and obtains a temperature from the temperature sensor (23) and controls the power inverter circuit (21) and the fan (24). When the temperature is lower than a specified value, the control part (22) holds failure determination of the fan (24) based on the revolution number of the fan (24).SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a power conversion device incorporating a fan. [Background technology]

[0002] It is expected that EVs will become more widespread worldwide in the future. The spread of EVs will require the development of EV chargers with high utility. There are many EV charging standards, but most of the general EV charging standards only stipulate the compatibility between EVs and EV chargers. The EV itself or the EV charger itself operates in conjunction with the charging standard operation, and if it does not follow that operation, it will malfunction. If operation stops due to a minor malfunction, the EV charger will be evaluated by the market as having insufficient performance, and the opportunity to gain market share will be lost. Therefore, each EV charger manufacturer is required to design equipment that takes into account all possible eventualities.

[0003] When charging an EV charger, the temperature inside the charger can rise to over 100°C due to heat generated by switching devices inside the case (e.g., MOSFETs (Metal Oxide Semiconductor Field Effect Transistors) and IGBTs (Insulated Gate Bipolar Transistors)). If no cooling mechanism is installed, it is expected that charging will stop for a while due to the high temperature, and then start again, repeatedly. As a solution, it is possible to incorporate a cooling fan (see, for example, Patent Document 1). Devices equipped with fans often have a failure detection mode that determines that a failure has occurred when the fan's rotation speed falls below a low rotation threshold. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2003-92837 A Summary of the Invention [Problem to be solved by the invention]

[0005] When an EV charger is installed outdoors in cold climates, the fan may freeze and become unable to rotate. In the above failure detection mode, a frozen fan may be judged as a failure, causing the entire system to shut down.

[0006] The present disclosure has been made in consideration of these circumstances, and has an object to provide a power conversion device that can accurately determine whether a cooling fan has broken down or is frozen. [Means for solving the problem]

[0007] In order to solve the above problems, a power conversion device according to an embodiment of the present disclosure includes a housing, a power conversion circuit, a fan for cooling the power conversion circuit, a rotation speed sensor for measuring a rotation speed of the fan, a temperature sensor for measuring a temperature inside the housing, and a control unit for acquiring the rotation speed of the fan from the rotation speed sensor, acquiring the temperature from the temperature sensor, and controlling the power conversion circuit and the fan. When the temperature is lower than a predetermined value, the control unit suspends a failure determination of the fan based on the rotation speed of the fan. Effect of the Invention

[0008] According to the present disclosure, it is possible to accurately determine whether a cooling fan is broken or frozen. [Brief description of the drawings]

[0009] [Figure 1] 1 is a diagram showing an overall configuration of a distributed power supply system according to an embodiment; [Diagram 2] 1 is a diagram illustrating a configuration example of a vehicle power conversion device. [Diagram 3] FIG. 2 is a perspective view showing the locations of the heat sink, the transformer, the first board, and the second board. [Figure 4] 4 is a flowchart showing a first operation example of the vehicle power conversion device according to the embodiment. [Diagram 5]5 is a flowchart showing a second operation example of the vehicle power conversion device according to the embodiment. [Figure 6] 6 is a flowchart showing a third operation example of the vehicle power conversion device according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] 1 is a diagram showing an overall configuration of a distributed power system 1 according to an embodiment. The distributed power system 1 according to the embodiment includes a power conversion system 10 installed indoors, and a vehicle power conversion device 20 installed outdoors. The power conversion system 10 includes a DC / DC converter 11 for a solar cell 5, a DC / DC converter 13 for a stationary power storage unit 6, an inverter 12, and a control unit 14. The power conversion system 10 may be configured as an integrated power conversion system (also called a power station (registered trademark)) that integrates a power conditioner function for a solar power generation system and a power conditioner function for a power storage system, or may be configured as a combination of a power conditioner for a solar power generation system and a power conditioner for a power storage system that are independent of each other.

[0011] The solar cell 5 is a power generating device that utilizes the photovoltaic effect to directly convert light energy into DC power. As the solar cell 5, a heterojunction solar cell, a polycrystalline silicon solar cell, a single crystal silicon solar cell, a thin-film silicon solar cell, a compound solar cell, or the like can be used. The solar cell 5 is connected to a DC / DC converter 11 of the power conversion system 10, and outputs the generated power to the power conversion system 10.

[0012] The DC / DC converter 11 is a converter connected between the solar cell 5 and the DC bus Bd, capable of adjusting the voltage of the DC power output from the solar cell 5. The DC / DC converter 11 can be configured, for example, as a boost chopper. As a basic control, the DC / DC converter 11 performs MPPT (Maximum Power Point Tracking) control so that the output power of the solar cell 5 is maximized. The DC / DC converter 11 can also control the boost rate so that the measured value of the voltage of the DC bus Bd is maintained at a target value, or so that the measured value of the power generated by the solar cell 5 is maintained at a target value. This control is invoked when it is necessary to suppress the amount of power generated by the solar cell 5.

[0013] The inverter 12 is connected between the DC bus Bd and the distribution board 3. The inverter 12 converts DC power input from the DC bus Bd into AC power, and outputs the converted AC power to the distribution board 3. A commercial power system (hereinafter simply referred to as system 2) is connected to the distribution board 3. A load 4 is also connected to the distribution board 3. The load 4 is a general term for loads within the home. The inverter 12 can also convert AC power supplied from the system 2 via the distribution board 3 into DC power, and output the converted DC power to the DC bus Bdc.

[0014] The stationary power storage unit 6 is capable of charging and discharging power, and includes a storage battery such as a lithium ion storage battery, a nickel metal hydride storage battery, or a lead storage battery, or a capacitor such as an electric double layer capacitor or a lithium ion capacitor. The stationary power storage unit 6 is connected to a DC / DC converter 13 of the power conversion system 10, and charging and discharging of the stationary power storage unit 6 are controlled by the DC / DC converter 13. The DC / DC converter 13 is a bidirectional DC / DC converter connected between the stationary power storage unit 6 and the DC bus Bd, and for charging and discharging the stationary power storage unit 6.

[0015] DC / DC converter 13 can charge / discharge stationary power storage unit 6 with a constant current (CC) or a constant voltage (CV). DC / DC converter 13 can also charge / discharge stationary power storage unit 6 so that the voltage of DC bus Bd maintains a target value.

[0016] The control unit 14 performs overall control of the entire power conversion system 10. The control unit 14 can generate command values ​​for the DC / DC converter 11 for the solar cell 5, the inverter 12, and the DC / DC converter 13 for the stationary power storage unit 6, and control the DC / DC converter 11, the inverter 12, and the DC / DC converter 13, respectively. The control unit 14 can also generate command values ​​for the DC / DC converter 21 for the electric vehicle 7, and notify the control unit 22 of the vehicle power conversion device 20 of the command values.

[0017] The vehicle power conversion device 20 is a V2H device that links the indoor power conversion system 10 and the electric vehicle 7 and charges and discharges a power storage unit mounted on the electric vehicle 7. The vehicle power conversion device 20 and the electric vehicle 7 are connected by a DC charge / discharge cable 30. A gun connector 31 is attached to the tip of the charge / discharge cable 30, and the vehicle power conversion device 20 and the electric vehicle 7 are connected when the user inserts the gun connector 31 into an inlet of the electric vehicle 7.

[0018] The CHAdeMO (registered trademark) V2H guidelines, a representative EV charging standard, prescribes signals, communications, charge / discharge sequences, and the like between an electric vehicle and a charger (vehicle power conversion device 20 in this embodiment). A CAN (Controller Area Network) communication line is included in the charge / discharge cable 30. The vehicle power conversion device 20 can obtain vehicle information (such as a vehicle ID, total battery capacity, and SOC (State Of Charge)) from the electric vehicle 7 via CAN communication.

[0019] The vehicle power conversion device 20 includes a DC / DC converter 21, a control unit 22, a temperature sensor 23, a fan 24, a drive unit 25, a rotation speed sensor 26, and an alarm unit 27. The power storage unit mounted on the electric vehicle 7 is a chargeable and dischargeable power storage unit including a plurality of cells, and is mainly used as a power source for driving the driving motor. The cells may be lithium ion battery cells, nickel metal hydride battery cells, electric double layer capacitor cells, lithium ion capacitor cells, etc.

[0020] One end of the DC / DC converter 21 is connected to the power storage unit of the electric vehicle 7 via a charge / discharge cable 30, and the other end of the DC / DC converter 21 is connected to a DC bus Bd (more specifically, a DC cable connecting the power conversion system 10 and the vehicle power conversion device 20).

[0021] The DC / DC converter 21 is a bidirectional DC / DC converter for charging and discharging a power storage unit mounted on the electric vehicle 7. The DC / DC converter 21 can charge and discharge the power storage unit mounted on the electric vehicle 7 with a constant current (CC) or a constant voltage (CV).

[0022] The control unit 22 performs overall control of the entire vehicle power conversion device 20. The control unit 22 generates a command value for the DC / DC converter 21 by referring to the SOC of the power storage unit mounted on the electric vehicle 7. Note that as the command value for the DC / DC converter 21, a command value notified from the control unit 14 of the power conversion system 10 or the control unit of the electric vehicle 7 may be used.

[0023] The temperature sensor 23 measures the temperature inside the housing of the vehicle power conversion device 20 and outputs the measured temperature to the control unit 22. For example, a thermistor or a thermocouple can be used as the temperature sensor 23. The temperature sensor 23 may be installed at any position inside the housing. For example, the temperature sensor 23 may be installed on a board on which the DC / DC converter 21 is mounted.

[0024] The fan 24 is a fan for cooling the DC / DC converter 21. In this embodiment, it is assumed that a DC fan with a PWM control function is used. A DC fan with a PWM control function is a fan whose rotation speed can be controlled by applying a PWM duty. The closer the PWM duty is to 0, the slower the rotation speed becomes, and the closer the PWM duty is to 1, the faster the rotation speed becomes.

[0025] The rotation speed sensor 26 measures the rotation speed of the fan 24 and outputs the measured rotation speed to the control unit 22. The rotation speed sensor 26 can be, for example, a pulse sensor that outputs a square wave signal with two periods per rotation of the fan motor.

[0026] The control unit 22 determines the rotation speed of the fan 24 based on the temperature obtained from the temperature sensor 23. The control unit 22 determines the rotation speed of the fan 24 by, for example, referring to a map that is stored in advance and that defines the relationship between the temperature inside the cabinet and the rotation speed of the fan 24. The control unit 22 supplies a PWM duty corresponding to the determined rotation speed of the fan 24 to the drive unit 25. The drive unit 25 drives the fan motor based on the PWM duty supplied from the control unit 22.

[0027] When the temperature inside the cabinet becomes high, the control unit 22 increases the rotation speed of the fan 24. When the temperature inside the cabinet becomes high, the control unit 22 can reduce the current command value or voltage command value of the DC / DC converter 21 to reduce the charge / discharge power. As an inspection mode for the fan 24, the control unit 22 supplies a predetermined PWM duty to the drive unit 25 and checks whether the rotation speed acquired from the rotation speed sensor 26 is the desired rotation speed, thereby checking whether the fan 24 is operating normally.

[0028] The notification unit 27 is a user interface for presenting information to the user, and includes at least one of an LED lamp, a display, and a speaker, for example.

[0029] FIG. 2 is a diagram showing a configuration example of a vehicle power conversion device 20. The vehicle power conversion device 20 shown in FIG. 2 includes a vertically long box-shaped housing H. A wiring space Sw is provided at the bottom inside the housing H. A sealed space Se for sealingly arranging the first board B1 and the second board B2 is provided above the wiring space Sw. The sealed space Se is formed, for example, of a vertically long metal box. In the metal box, the transformer TR, the first board B1, and the second board B2 are arranged vertically in order from the top.

[0030] The first substrate B1 is mounted with, for example, switching devices (power semiconductor elements such as MOSFETs and IGBTs) constituting the DC / DC converter 21, a reactor, a capacitor, and a temperature sensor 23. The second substrate B2 is mounted with, for example, a control unit 22, a drive unit 25, a rotation speed sensor 26, and a relay.

[0031] A heat sink Hs is provided on the rear surface of the metal box on which the transformer TR, the first board B1, and the second board B2 are arranged. The heat sink Hs is a heat dissipation member having a plurality of heat dissipation fins.

[0032] 3 is a perspective view showing the locations of the heat sink Hs, the transformer (reactor L), the first board B1, and the second board B2. The temperature of the transformer, reactor, and switching device can rise to 100°C or higher, so it is desirable to place these electronic components and the heat sink Hs as close as possible.

[0033] Returning to FIG. 2, the fan 24 is disposed in the lower part of the housing H and agitates the temperature inside the cabinet. A lower vent Vb is disposed in the lower part of the housing H, and an upper vent Vt is disposed in the upper part of the housing H. Cooling air flows into the housing H from the lower vent Vb, passes through the heat sink Hs, rises, and exits from the upper vent Vt. Since the transformer TR, reactor, and switching device, which are the main heat sources in the housing H, are disposed in the upper part of the housing H, the air density is lower in the upper part of the housing H, and an updraft is more likely to occur in the housing H. Furthermore, the fan 24 generates an upward wind, thereby increasing the amount of air circulation.

[0034] In this embodiment, attention is focused on determining the operating status of the fan 24 that is operated in conjunction with the charge / discharge operation. Minimizing power consumption and reducing costs are particularly required for the vehicle power conversion device 20 that is linked to a home solar power generation system, a power storage system, or a hybrid power storage system that integrates both (also called a generation / storage linked system).

[0035] Generally, charging and discharging operations are performed by power conversion using a switching device, but if the power conversion operation continues for a long time, the temperature inside the housing H will rise. If heat dissipation is insufficient, the heat tolerance range of the switching device and other components will be exceeded, leading to component failure. By releasing the heat generated inside the housing H to the outside or stirring the air inside the housing H, the temperature rise inside the housing H can be suppressed, making it possible to perform charging and discharging operations for a long time.

[0036] The vehicle power conversion device 20 is required to operate in various usage scenarios. Consider a scenario in which a family in a cold region owns multiple electric vehicles 7 and shares one vehicle power conversion device 20 with the multiple electric vehicles 7. For example, if a first electric vehicle 7 is charged in 10 hours, and a second electric vehicle 7 is scheduled to be charged after a three-hour pause, the rotating part of the fan 24 may freeze due to low temperature and high humidity during the three-hour pause. If the fan 24, which should operate in conjunction with the charging operation, freezes and stops, and is determined to be broken, the charging operation will also stop. In particular, in a location where the vehicle power conversion device 20 is installed outdoors in a cold region, the rotating part of the fan 24 is likely to freeze at night.

[0037] While it is possible to provide necessary and sufficient moisture protection for the electronic components inside the housing H, it is difficult to provide complete moisture protection for the mechanical components (fans, relays, etc.) due to their nature. In this embodiment, a vehicle power conversion device 20 is realized that can determine whether the fan 24 is frozen while referring to the temperature inside the cabinet, and can quickly thaw the fan 24 if it is frozen.

[0038] 2, storage spaces for storing heat sources are provided near the fan 24. Storage boxes with high thermal conductivity are provided in the first storage space Sh1 and the second storage space Sh2, respectively. The first storage box provided in the first storage space Sh1 is provided in contact with a rectangular frame that houses a plurality of blades of the fan 24, with no space between them. The second storage box provided in the second storage space Sh2 is provided in non-contact with the rectangular frame, with a space between them.

[0039] The first storage box is a storage box for storing a heat source that does not generate flames, and is a storage box for heating the fan 24 by thermal coupling. For example, an electric heater is stored in the first storage box. Also, a disposable warmer can be stored in the first storage box. In the vehicle power conversion device 20 that is not a cold region specification, a model in which an electric heater is not installed is generally used. A disposable warmer is a non-electric heat source, and is a heat source that is temporarily installed by a user. In the case where a heat source other than an electric heater is installed in the first storage box, a door is installed in the first storage box for a user to put in and take out the heat source. Note that the first storage box may be installed on any surface (excluding the air blowing surface) of the rectangular frame of the fan 24. Also, the first storage box may be installed on multiple surfaces (excluding the air blowing surface) of the rectangular frame.

[0040] The second storage box is a storage box for storing a heat source that generates a flame, and is a storage box for heating the fan 24 with the heat from the grilling. The top of the second storage box may be open, or may be covered with a lid with air holes. The second storage box can store, for example, a candle, a gas burner, a lighter, and a brazier. The candle, gas burner, lighter, and brazier are non-electrical heat sources that are temporarily installed by the user. The second storage box is provided with a door that allows the user to put in and take out the heat source.

[0041] The operating power of the DC / DC converter 21, the control unit 22, the temperature sensor 23, the fan 24, the drive unit 25, the rotation speed sensor 26, the notification unit 27, and the electric heater of the vehicle power conversion device 20 is usually supplied from the grid 2 via the power conversion system 10. In the event of a power outage, power can be supplied from the solar cell 5 or the stationary power storage unit 6 via the power conversion system 10. Also, power can be supplied from the electric vehicle 7 by connecting a wire to the cigarette lighter socket of the electric vehicle 7. Also, an emergency storage battery or capacitor may be mounted inside the vehicle power conversion device 20.

[0042] In order to eliminate power consumption when not in use, the home vehicle power conversion device 20 basically starts operation at the activation timing caused by the user's operation. The user can directly operate an operation switch installed on the vehicle power conversion device 20 to instruct the vehicle power conversion device 20 to start operation. The user can also set the operation start time in advance and operate the vehicle power conversion device 20 by timer.

[0043] Furthermore, when the vehicle power conversion device 20 is connected to a HEMS (Home Energy Management System) controller installed indoors, the user can operate the vehicle power conversion device 20 from an HEMS terminal via the HEMS controller. Furthermore, when a smartphone held by the user is linked to the vehicle power conversion device 20 or the HEMS controller, the user can also operate the vehicle power conversion device 20 from the smartphone.

[0044] Basically, the fan 24 operates while the DC / DC converter 21 is operating, and does not operate while the DC / DC converter 21 is stopped. The control unit 22 may operate the fan 24 at a constant fixed rotation speed while the DC / DC converter 21 is operating, or may operate the fan while adaptively changing the rotation speed according to the inside temperature.

[0045] In this embodiment, three abnormal modes of the fan 24 are defined: a deterioration mode over time, a failure mode, and a frozen mode. The deterioration mode is a state in which a decrease in the rotation speed of the fan 24 due to long-term use is observed. The deteriorated fan 24 is no longer able to maintain a constant rotation speed. The deterioration of the fan 24 over time progresses due to wear or corrosion of the resin parts and bearings, accumulation of dust, etc.

[0046] A failure mode is a state in which rotation is impossible due to a mechanical or electrical malfunction. For example, a state in which rotation is impossible due to a part inside the housing H falling between the blades and getting caught between the blades, a state in which rotation is impossible due to physical damage to a mechanism (bearings, etc.), a state in which rotation is impossible due to a break in a current line or a signal line, etc.

[0047] The frozen mode is a state in which the rotating part is frozen and cannot rotate. When the fan 24 does not rotate even when powered, this may be either the failure mode or the frozen mode, but in this embodiment, a control is introduced to accurately distinguish between the failure mode and the frozen mode. In the following explanation, the failure mode is a concept that also includes the deterioration mode (failure mode in a broad sense).

[0048] 4 is a flowchart showing a first operation example of the vehicle power conversion device 20 according to the embodiment. In the first operation example, it is assumed that the vehicle power conversion device 20 is equipped with an electric heater. When an operation start command is issued based on a user operation or the control of the HEMS controller, the control unit 22 starts the operation of the DC / DC converter 21 (S10) and starts the operation of the fan 24 (S11). The control unit 22 acquires the inside temperature from the temperature sensor 23 and acquires the rotation speed of the fan 24 from the rotation speed sensor 26 (S12).

[0049] The control unit 22 compares the internal temperature with a predetermined value (e.g., 4°C) (S13). If the internal temperature is less than the predetermined value (N in S13), the control unit 22 compares the rotation speed of the fan 24 with a threshold value (S14). The threshold value is a threshold value for determining whether the rotation speed of the fan 24 is normal or not, and is set to a value according to the specifications of the fan 24 to be used.

[0050] If the rotation speed of the fan 24 is less than the threshold value (Y in S14), the control unit 22 operates the electric heater (S15). If the electric heater is already operating, it continues to operate. The process transitions to step S110. If the rotation speed of the fan 24 is equal to or greater than the threshold value (N in S14), the control unit 22 stops the electric heater (S16). If the electric heater is already stopped, it continues to be stopped. The process transitions to step S110.

[0051] In step S13, if the temperature inside the cabinet is equal to or higher than a predetermined value (Y in S13), the control unit 22 compares the number of revolutions of the fan 24 with a threshold value (S17). If the number of revolutions of the fan 24 is less than the threshold value (Y in S17), the control unit 22 determines that the fan 24 is in a broad failure mode, and causes the notification unit 27 to notify a failure alert (S18). The control unit 22 executes, for example, at least one of turning on a fan failure lamp, displaying a failure message of the fan 24 on a display, and outputting an audio message of the failure of the fan 24 from a speaker. If the number of revolutions of the fan 24 is equal to or higher than the threshold value (N in S17), the control unit 22 stops the electric heater (S19). If the electric heater has already stopped, it continues to be stopped. The process proceeds to step S110.

[0052] The control unit 22 repeats the processes of steps S12 to S19 until an operation stop instruction based on a user operation or control of the HEMS controller is acquired, or until charging of the power storage unit mounted on the electric vehicle 7 is completed (Y of S110).

[0053] In operation example 1, when the inside temperature is below a predetermined value, the failure determination of the fan 24 based on the rotation speed of the fan 24 is suspended. When the inside temperature is below a predetermined value, it is difficult to determine whether the fan 24 is in a broad failure mode or a freeze mode, so the control unit 22 goes into an observation state and waits to make a failure determination until the inside temperature rises.

[0054] 5 is a flowchart showing an operation example 2 of the vehicle power conversion device 20 according to the embodiment. In the operation example 2, it is assumed that a reserved operation setting in which an operation start time is specified by a user is made in advance. The control unit 22 acquires the reserved operation setting input by the user (S20). When it is a predetermined time before the reserved operation start time (Y in S21), the control unit 22 acquires the inside temperature from the temperature sensor 23 (S22).

[0055] The control unit 22 compares the inside temperature with a predetermined value (e.g., 4°C) (S23). If the inside temperature is less than the predetermined value (N in S23), the control unit 22 operates the electric heater (S24). If the electric heater is already operating, it continues to operate. The control unit 22 determines the power to be supplied to the electric heater based on the time until the reserved operation start time and the temperature difference between the inside temperature and the predetermined value. The control unit 22 determines the power to be supplied to the electric heater, for example, by referring to a map stored in advance that specifies the relationship between the combination of the time until the reserved operation start time and the temperature difference, and the power to be supplied to the electric heater. The process proceeds to step S26.

[0056] When the temperature inside the refrigerator is lower than a predetermined value and an immediate operation start command is received by a direct operation of the user or by control of the HEMS controller, the control unit 22 sets the intensity of the electric heater to be stronger than when an operation start command is received in advance. For example, the control unit 22 may supply the maximum power specified in the specifications to the electric heater in order to quickly defrost the fan 24.

[0057] In step S23, if the temperature inside the chamber is equal to or higher than the predetermined value (Y in S23), the control unit 22 stops the electric heater (S25). If the electric heater has already been stopped, it continues to be stopped. The process proceeds to step S26.

[0058] When the reserved operation start time arrives (Y in S26), the control unit 22 executes the processes from step S10 onwards shown in Fig. 4. Until the reserved operation start time arrives (N in S26), the processes from step S22 to step S25 are repeated. In the second operation example, the electric heater is operated in advance in preparation for the reserved operation, so that the frozen fan 24 can be thawed in advance.

[0059] 6 is a flowchart showing an operation example 3 of the vehicle power conversion device 20 according to the embodiment. In the operation example 3, it is assumed that the vehicle power conversion device 20 is not equipped with an electric heater. When an operation start command is issued based on a user operation or the control of the HEMS controller, the control unit 22 starts the operation of the DC / DC converter 21 (S30) and starts the operation of the fan 24 (S31). The control unit 22 acquires the inside temperature from the temperature sensor 23 and acquires the rotation speed of the fan 24 from the rotation speed sensor 26 (S32).

[0060] The control unit 22 compares the temperature inside the cabinet with a predetermined value (for example, 4°C) (S33). If the temperature inside the cabinet is less than the predetermined value (N in S33), the control unit 22 compares the number of revolutions of the fan 24 with a threshold value (S34). If the number of revolutions of the fan 24 is less than the threshold value (Y in S34), the control unit 22 causes the notification unit 27 to notify a freeze alert (S35). For example, the control unit 22 executes at least one of turning on a fan freeze lamp, displaying a message indicating that the fan 24 is frozen on a display, and outputting an audio message indicating that the fan 24 is frozen from a speaker. The control unit 22 may also notify a freeze alert to a user's smartphone. When the user notices the freeze alert, the user places a non-electrical heat source, such as a disposable warmer, in the first storage space Sh1 or the second storage space Sh2 to heat the fan 24. The process proceeds to step S310.

[0061] In step S34, if the rotation speed of the fan 24 is equal to or greater than the threshold (N in S34), the control unit 22 cancels the freeze alert (S36). The control unit 22 executes at least one of the following: turning off the fan freeze lamp, displaying a thawing message for the fan 24 on the display, and outputting an audible thawing message for the fan 24 from the speaker. The control unit 22 may also notify the user's smartphone of the thawing message. When the user notices the thawing message, he or she can collect a non-electrical heat source such as a disposable warmer from the first storage space Sh1 or the second storage space Sh2. If the freeze alert has not been activated from the beginning, the freeze alert remains inactive. The process proceeds to step S310.

[0062] In step S33, if the temperature inside the cabinet is equal to or higher than a predetermined value (Y in S33), the control unit 22 compares the rotation speed of the fan 24 with a threshold value (S37). If the rotation speed of the fan 24 is less than the threshold value (Y in S37), the control unit 22 determines that the fan 24 is in a broad failure mode, and causes the notification unit 27 to notify a failure alert (S38). If the rotation speed of the fan 24 is equal to or higher than the threshold value (N in S37), the control unit 22 cancels the freeze alert (S39). If a freeze alert was not activated from the beginning, the freeze alert remains inactive. The process proceeds to step S310.

[0063] The control unit 22 repeats the processes of steps S32 to S39 until an operation stop instruction based on a user operation or control of the HEMS controller is acquired, or until charging of the power storage unit mounted on the electric vehicle 7 is completed (Y of S310).

[0064] The third operation example can also be applied to a situation where the power supply for the electric heater cannot be secured due to a power outage or the like in the vehicle power conversion device 20 equipped with an electric heater (black start situation).

[0065] In this embodiment, the control unit 22 continues to energize the DC / DC converter 21 even when the inside temperature is lower than a predetermined value and the rotation speed of the fan 24 is below a threshold value. Therefore, the inside temperature naturally rises due to heat generation accompanying losses in the DC / DC converter 21. If there is sufficient margin in the heat resistance design of the electronic components in the sealed space Se, the design may be such that the fan 24 waits for natural thawing.

[0066] As described above, according to this embodiment, when the temperature inside the storage compartment is low, the failure determination of the fan 24 is suspended, thereby enabling an accurate determination of whether the fan 24 is broken or frozen. In addition, by mounting an electric heater for defrosting the fan 24 or by ensuring space for installing another heat source, a frozen fan 24 can be defrosted early. Furthermore, according to this embodiment, a vehicle power conversion device 20 for cold climates, in which unnecessary system shutdowns are suppressed, can be produced at low cost.

[0067] The present disclosure has been described above based on the embodiments. The embodiments are merely examples, and it will be understood by those skilled in the art that various modifications are possible in the combination of each component and each processing step, and that such modifications are also within the scope of the present disclosure.

[0068] The process of determining the failure mode and freezing mode of the fan 24 according to the present disclosure can be applied to power conversion devices other than the vehicle power conversion device 20, so long as the power conversion device is equipped with a fan. For example, the process can be applied to a power conditioner for a solar power generation system, a power conditioner for a power storage system, a power conditioner for a hybrid power storage system, a converter device for a stationary storage battery, and the like.

[0069] The embodiment may be specified by the following items.

[0070] [Item 1] A housing (H) and A power conversion circuit (21); a fan (24) for cooling the power conversion circuit (21); a rotation speed sensor (26) for measuring the rotation speed of the fan (24); A temperature sensor (23) for measuring a temperature inside the housing (H); a control unit (22) that acquires the rotation speed of the fan (24) from the rotation speed sensor (26) and the temperature from the temperature sensor (23) and controls the power conversion circuit (21) and the fan (24), When the temperature is lower than a predetermined value, the control unit (22) reserves the decision on a failure of the fan (24) based on the rotation speed of the fan (24). A power converter (22). This makes it possible to accurately determine whether the fan (24) is broken or frozen. [Item 2] the control unit (22) determines that the fan (24) has a malfunction when the temperature is equal to or higher than the predetermined value and the rotation speed of the fan (24) is less than a threshold value while the power conversion circuit (21) is energized; Item 2. The power conversion device (22) according to item 1. This can improve the accuracy of determining whether or not there is a malfunction in the fan (24). [Item 3] further comprising an electric heater (Sh1) for heating the fan (24); the control unit (22) operates the electric heater (Sh1) in response to a prior operation start instruction or an immediate operation start instruction when the temperature is lower than the predetermined value. Item 2. The power conversion device (22) according to item 1. This allows the frozen fan (24) to be thawed quickly. [Item 4] When the control unit (22) receives an immediate operation start instruction while the temperature is lower than a predetermined value, the control unit (22) sets the intensity of the electric heater (Sh1) to be stronger than when the control unit (22) receives a prior operation start instruction. Item 3. A power conversion device (22) according to item 3. This makes it possible to thaw the frozen fan (24) as soon as possible after the start of operation. [Item 5] When the rotation speed of the fan (24) reaches a normal value after the electric heater (Sh1) is operated, the control unit (22) stops the electric heater (Sh1). Item 3. A power conversion device (22) according to item 3. This prevents unnecessary or harmful heating. [Item 6] Further, an installation space (Sh2) for temporarily installing a non-electrical heat source is provided near the fan (24). Item 2. The power conversion device (22) according to item 1. This makes it possible to thaw the frozen fan (24) early even if the electric heater (Sh1) is not installed or if the power source for the electric heater (Sh1) cannot be secured. [Item 7] Further comprising a notification unit (27) for presenting information to a user, When the temperature is lower than the predetermined value and the number of revolutions of the fan is less than a threshold value, the control unit (22) causes the notification unit (27) to output a freeze alert. Item 10. The power conversion device (22) according to item 1 or 6. This can encourage the user to install a non-electrical heat source. [Item 8] the control unit (22) continues energizing the power conversion circuit (21) even when the temperature is lower than the predetermined value and the rotation speed of the fan (24) is less than a threshold value. Item 2. The power conversion device (22) according to item 1. This allows the inside of the housing (H) to be heated by Joule heat. [Explanation of symbols]

[0071] 1 distributed power system, 2 system, 3 distribution board, 4 load, 5 solar cell, 6 stationary power storage unit, 7 electric vehicle, 10 power conversion system, 11 DC / DC converter, 12 inverter, 13 DC / DC converter, 14 control unit, 20 vehicle power conversion device, 21 DC / DC converter, 22 control unit, 23 temperature sensor, 24 fan, 25 drive unit, 26 rotation speed sensor, 27 notification unit, 30 charge / discharge cable, 31 gun connector, Bd DC bus, H housing, Hs heat sink, L reactor, TR transformer, B1 first board, B2 second board, Sw wiring space, Sh1 first storage space, Sh2 second storage space, Vb lower ventilation port, Vt upper ventilation port.

Claims

1. A housing and A power conversion circuit; a fan for cooling the power conversion circuit; A rotation speed sensor that measures the rotation speed of the fan; A temperature sensor that measures a temperature inside the housing; a control unit that acquires a rotation speed of the fan from the rotation speed sensor, acquires a temperature from the temperature sensor, controls the power conversion circuit and the fan, and performs a failure determination of the fan based on the rotation speed of the fan, The control unit skips a failure determination of the fan based on a rotation speed of the fan when the temperature is lower than a predetermined value. Power conversion equipment.

2. the control unit determines that the fan is broken when the temperature is equal to or higher than the predetermined value and the rotation speed of the fan is less than a threshold value while the power conversion circuit is energized. The power conversion device according to claim 1 .

3. Further comprising an electric heater for heating the fan; The control unit operates the electric heater in response to a prior operation start instruction or an immediate operation start instruction when the temperature is lower than the predetermined value. The power conversion device according to claim 1 .

4. When the control unit receives an immediate operation start instruction while the temperature is lower than a predetermined value, the control unit sets the intensity of the electric heater to be stronger than when the control unit receives a prior operation start instruction. The power conversion device according to claim 3 .

5. The control unit stops the electric heater when the rotation speed of the fan reaches a normal value after operating the electric heater. The power conversion device according to claim 3 .

6. Further, an installation space for temporarily installing a non-electrical heat source is provided near the fan. The power conversion device according to claim 1 .

7. Further comprising a notification unit for presenting information to a user, The control unit causes the notification unit to output a freeze alert when the temperature is lower than the predetermined value and the rotation speed of the fan is less than a threshold value. The power conversion device according to claim 1 or 6.

8. The control unit continues energizing the power conversion circuit even when the temperature is lower than the predetermined value and the rotation speed of the fan is less than a threshold value. The power conversion device according to claim 1 .

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