Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
  • H02M7/00—Conversion of AC power input into DC power output; Conversion of DC power input into AC power output
  • H02M7/42—Conversion of DC power input into AC power output without possibility of reversal
  • H02M7/44—Conversion of DC power input into AC power output without possibility of reversal by static converters
  • H02M7/48—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode

Definitions

• Embodiments of the present invention relate to a device and a temperature abnormality detection method.
• the cooling method for devices such as power conversion equipment often involves forced air cooling using a cooling fan (fan), which expels heat generated by heat-generating elements inside the device to the outside.
• a cooling fan fan
• Such devices are designed to prevent secondary deterioration, as the temperature inside the device rises if ventilation is no longer possible due to a cooling fan failure.
• the object of the present invention is to improve the reliability of temperature protection for devices that use fans for forced cooling.
• the device houses a heating element that generates heat when powered on within its own housing, and uses a fan provided in the housing to forcibly cool the inside of the housing.
• the device includes a first temperature sensor, a second temperature sensor, and a controller.
• the first temperature sensor is a temperature sensor positioned upwind of the fan in the flow of air generated by the fan, and detects the temperature upwind of the fan.
• the second temperature sensor is a temperature sensor positioned downstream of the fan in the flow of air generated by the fan, and detects the temperature downstream of the fan.
• the controller detects a decrease in air volume using the temperature difference between the temperature upwind of the fan and the temperature downwind of the fan.
• FIG. 1 is a schematic configuration diagram of a power conversion device according to an embodiment; 1 is a configuration diagram of a power conversion device according to an embodiment; FIG. 10 is a configuration diagram of a modified example of the power conversion device according to the embodiment.
• FIG. 10 is a configuration diagram of a modified example of the power conversion device according to the embodiment.
• FIG. 2 is a circuit diagram showing the internal configuration of a cell converter according to the embodiment.
• FIG. 2 is a circuit diagram showing the internal configuration of a cell converter according to the embodiment.
• FIG. 10 is a circuit diagram showing the internal configuration of a cell converter according to a modified example of the embodiment.
• FIG. 10 is a circuit diagram showing the internal configuration of a cell converter according to a modified example of the embodiment.
• FIG. 10 is a circuit diagram showing the internal configuration of a cell converter according to a modified example of the embodiment.
• FIG. 10 is a circuit diagram showing the internal configuration of a cell converter according to a modified example of the embodiment.
• FIG. 10 is a circuit diagram showing the internal configuration of a cell converter according to a modified example of the embodiment.
• FIG. 3 is a diagram for explaining the arrangement of temperature sensors on a converter board according to an embodiment.
• FIG. 3 is a diagram for explaining the arrangement of temperature sensors on a converter board according to an embodiment.
• FIG. 2 is a diagram illustrating the configuration of a controller according to the embodiment.
• 10 is a flowchart of a temperature monitoring process according to the embodiment.
• FIG. 10 is a diagram for explaining a temperature monitoring process according to the embodiment.
• the power conversion device illustrated below is an example of a device.
• This power conversion device supplies desired AC power to an electric motor, which is an example of a load.
• the term "connect” in the embodiments includes “electrically connect.”
• components having the same or similar functions are denoted by the same reference numerals. Duplicate descriptions of those components may be omitted.
• Electrical connection may simply be referred to as "connected.” If the flow of power (power flow) during power running of a power conversion device is from the input side (R, S, T side) to the output side (U, V, W side), the power converter on the input side performs forward conversion (conversion from AC to DC) and the power converter on the output side performs inverse conversion (conversion from DC to AC). Therefore, the power converter on the input side will be called a converter and the power converter on the output side will be called an inverter.
• cooling fans used for this type of forced air cooling come in a variety of specifications, including AC (Alternating Current) fans and EC (Electronically Commutated) fans. Some of these cooling fans have a function to detect faults. This fault detection function differs depending on the type of cooling fan and the specifications of the individual fan. For example, some AC fans detect overload conditions using a thermal relay that operates at a specified temperature. Some EC fans have their own fault detection function. In none of the above cases does the actual state of the equipment be monitored.
• FIG. 1 is a schematic configuration diagram of a power conversion device 1 according to an embodiment.
• Fig. 2A is a configuration diagram of the power conversion device 1 according to an embodiment.
• Fig. 2B and Fig. 2C are configuration diagrams of modified examples of the power conversion device 1 according to an embodiment.
• the X-axis, Y-axis, and Z-axis directions which are orthogonal to each other in three-dimensional space, are parallel to each other.
• the left-right direction of the power conversion device 1 is parallel to the X-axis direction.
• the positive X-axis direction is the direction from the right side to the left side of the power conversion device 1.
• the front-rear direction of the power conversion device 1 is parallel to the Y-axis direction.
• the positive Y-axis direction is the direction from the front to the rear of the power conversion device 1.
• the up-down direction of the power conversion device 1 is parallel to the Z-axis direction.
• the positive Z-axis direction is the direction from the bottom to the top of the power conversion device 1.
• the power conversion device 1 of this embodiment includes a transformer panel 10, a converter panel 20, and a control panel 30, which are arranged in order in the X-axis direction.
• the transformer panel 10 includes a housing 11 and a transformer 12 .
• the housing 11 accommodates the transformer 12 therein.
• the transformer 12 is, for example, a three-phase transformer whose primary side has U-phase, V-phase, and W-phase.
• a temperature sensor 14 is provided directly below the cooling fan 13, and a temperature sensor 15 is provided in the path of exhaust air from the cooling fan 13.
• the area directly below the cooling fan 13 is sometimes referred to as an intake section 16.
• the path of exhaust air from the cooling fan 13 is sometimes referred to as an exhaust section 17.
• the temperature sensor 14 detects the internal temperature of the transformer panel 10 .
• the temperature sensor 15 detects the exhaust temperature of the transformer panel 10 .
• the converter board 20 includes a housing 21 and a power converter 22 .
• the housing 21 accommodates therein a power converter 22.
• the power converter 22 is a power converter that converts, for example, AC power on the secondary side of the transformer 12 into desired power.
• the housing 21 includes a frame, a top panel, side panels, and a door.
• the top plate of the housing 21 is provided with a ventilation hole for discharging warm air generated by losses in the power converter 22.
• a cooling fan 23 for discharging the warm air is provided in the ventilation hole in the top plate of the housing 21.
• An air intake is provided in the door or side panel of the housing 21.
• a temperature sensor 24 is provided directly below the cooling fan 23, and a temperature sensor 25 is provided in the exhaust path of the cooling fan 23.
• the area directly below the cooling fan 23 is sometimes referred to as an intake section 26.
• the exhaust path of the cooling fan 23 is sometimes referred to as an exhaust section 27.
• the temperature sensor 24 detects the internal temperature of the converter board 20 .
• the temperature sensor 25 detects the exhaust temperature of the converter board 20 .
• the power converter 22 includes a plurality of cell converters 22X.
• Each of the cell converters 22X includes a plurality of switching elements and a heat sink (heat dissipation fin) for dissipating heat from the plurality of switching elements.
• the multiple cell converters 22X include first-phase cell converters 22U1 and 22U2, second-phase cell converters 22V1 and 22V2, and third-phase cell converters 22W1 and 22W2, etc.
• the first, second, and third phases are the U, V, and W phases, respectively.
• the configuration of the power converter 22 is not limited to the above and may be modified as appropriate.
• the heat sink of the power converter 22 is configured to be divided for each cell converter 22X, for example.
• each heat sink may be provided with a cell converter 22X and a temperature sensor 28.
• the control panel 30 includes a housing 31 and a controller 32 .
• the housing 31 houses a controller 32 .
• the housing 31 includes a frame, a top panel, side panels, and a door.
• the top plate of the housing 31 is provided with a ventilation hole for discharging warm air generated by the loss of the controller 32.
• An air intake is provided on the door or side of the housing.
• this control panel 30 is not provided with a cooling fan dedicated to the control panel 30.
• the temperature sensor 34 detects the internal temperature of the control panel 30 .
• the partition plate between the control panel 30 and the converter panel 20 does not have any ventilation holes, and the control panel 30 is configured for natural air cooling.
• the partition plate between the control panel 30 and the converter panel 20 has ventilation holes, the control panel 30 would also be configured for forced air cooling, but a detailed description of this will be omitted.
• the power conversion device 1 includes, for example, a transformer 12, a power converter 22, and a controller 32.
• the power conversion device 1 has AC input terminals R, S, and T, and is connected to an AC power source 101 (electric power system) via these terminals.
• the power conversion device 1 has AC output terminals U, V, and W, and is connected to a load such as an electric motor 40 via these terminals.
• the primary winding of the transformer 12 is connected to the AC input terminals R, S, and T
• the secondary winding of the transformer 12 is connected to the AC input side of the power converter 22
• the AC output side of the power converter 22 is connected to the AC output terminals U, V, and W.
• the controller 32 controls the on/off of the switching elements contained in the cell converters 22U1, 22U2, 22V1, 22V2, 22W1, and 22W2.
• the cell converters 22U1, 22U2, 22V1, 22V2, 22W1, and 22W2 are collectively referred to as the multiple cell converters 22X. Details of the controller 32 will be described later.
• the transformer 12 has a primary winding and a multi-group secondary winding.
• the primary winding is formed in a three-phase star connection.
• the secondary winding is formed of single-phase or three-phase windings that are insulated from each other.
• Three-phase AC power is supplied to the transformer 12 from the AC power source 101.
• the transformer 12 transforms the voltage of the AC power supplied from the AC power source 101 to the desired voltage according to the turns ratio, and supplies the AC power of the transformed voltage to each of the multiple cell converters 22X.
• Each cell converter 22X of the power converter 22 is, for example, a single-phase converter, which converts the single-phase AC power supplied from the secondary winding of the transformer 12 into DC power, and then converts the converted DC power into single-phase AC power of a desired frequency and voltage for output.
• Each cell converter 22X has the same circuit configuration.
• the power converter 22 configured in this manner is connected to the secondary side of the transformer 12 and serves as a load for the transformer 12. This will be described in detail later.
• FIG. 2A shows an example of wiring of a transformer 12A whose secondary side has a three-phase output.
• the secondary side of the transformer 12A is configured to include a three-phase winding.
• each phase (three phases) of the first group on the secondary side of the transformer 12A is connected to each phase of the input of the cell converter 22U1
• each phase (three phases) of the second group on the secondary side of the transformer 12A is connected to each phase of the input of the cell converter 22V1
• each phase (three phases) of the third group on the secondary side of the transformer 12A is connected to each phase of the input of the cell converter 22W1.
• the phases of the fourth group on the secondary side of the transformer 12A are connected to the input phases of the cell converter 22U2, the phases of the fifth group on the secondary side of the transformer 12A are connected to the input phases of the cell converter 22V2, and the phases of the sixth group on the secondary side of the transformer 12A are connected to the input phases of the cell converter 22W2.
• the secondary side of the transformer 12A may be configured to include a three-phase winding.
• FIG. 2B shows an example of wiring of a transformer 12B whose secondary side has a single-phase winding output.
• the first phase of the first group on the secondary side of transformer 12B is connected to the input of cell converter 22U1.
• the second phase of the first group on the secondary side of transformer 12B is connected to the input of cell converter 22V1.
• the third phase of the first group on the secondary side of transformer 12B is connected to the input of cell converter 22W1.
• the first phase of the second group on the secondary side of transformer 12B is connected to the input of cell converter 22U2.
• the second phase of the second group on the secondary side of transformer 12B is connected to the input of cell converter 22V2.
• the third phase of the second group on the secondary side of transformer 12B is connected to the input of cell converter 22W2.
• FIG. 2C shows an example of wiring of a transformer 12B whose secondary side has a single-phase winding output.
• each phase (three phases) of the first group and each phase (three phases) of the second group on the secondary side of the transformer 12A are connected to each phase of the input of the cell converter 22U1.
• Each phase (three phases) of the third group and each phase (three phases) of the fourth group on the secondary side of the transformer 12A are connected to each phase of the input of the cell converter 22V1.
• Each phase (three phases) of the fifth group and each phase (three phases) of the sixth group on the secondary side of the transformer 12A are connected to each phase of the input of the cell converter 22W1.
• each phase (three phases) of the seventh group and each phase (three phases) of the eighth group on the secondary side of the transformer 12A are connected to each phase of the input of the cell converter 22U2.
• Each phase (three phases) of the ninth group and each phase (three phases) of the tenth group on the secondary side of the transformer 12A are connected to each phase of the input of the cell converter 22V2.
• Each phase (three phases) of the eleventh group and each phase (three phases) of the twelfth group on the secondary side of the transformer 12A are connected to each phase of the input of the cell converter 22W2.
• the transformer 12B may include a phase shift transformer.
• the inverter on the output side of the cell converter.
• the first-phase cell converters 22U1 and 22U2, the second-phase cell converters 22V1 and 22V2, and the third-phase cell converters 22W1 and 22W2 are associated with each phase of AC.
• One pole of the output side of the cell converter 22U1, the cell converter 22V1, and the cell converter 22W1 are connected to each other and form the neutral point of the three-phase AC of the load circuit.
• One pole of the output side of the cell converter 22U2, the cell converter 22V2, and the cell converter 22W2 are connected to the AC output terminal U, the AC output terminal V, and the AC output terminal W, respectively.
• the other pole on the output side of the first-phase cell converter 22U1 and the other pole on the output side of the first-phase cell converter 22U2 are connected to each other.
• the other pole on the output side of the second-phase cell converter 22V1 and the other pole on the output side of the second-phase cell converter 22V2 are connected to each other.
• the other pole on the output side of the third-phase cell converter 22W1 and the other pole on the output side of the third-phase cell converter 22W2 are connected to each other.
• the power converter 22 configured in this manner is connected to the secondary side of the transformer 12 and serves as a load for the transformer 12 .
• the power conversion device 1 can convert the AC power supplied from the AC power source 101 into three-phase AC power of the desired frequency and voltage and supply it to the electric motor 40.
• the primary winding (input side) is star (Y) connected, but this is just an example, and a delta ( ⁇ ) connection may also be used.
• the secondary winding (output side) shown in FIG. 2B is an open winding in which the three-phase winding is electrically separated into a single phase, but this is just one example, and electrically separated multiple groups of three-phase phase-shift connections may also be used (FIG. 2A).
• the configuration shown in Fig. 2C can be applied to a system that handles high voltage.
• the transformer shown in Fig. 2C has three-phase secondary windings divided into multiple groups. Each pair of the three-phase secondary windings is grouped together, and each group is connected to a common cell converter 22U1.
• Figures 3A and 3B are circuit diagrams showing an example of the internal configuration of a cell converter 22X (X: U, V, W) of an embodiment.
• Figures 3C and 3D are circuit diagrams showing another example of the internal configuration of a cell converter 22X (X: U, V, W) of an embodiment.
• the configuration shown in Figure 3A is for receiving and converting three-phase AC power.
• the cell converter 22X has input terminals IN1, IN2, and IN3 and output terminals OUT1 and OUT2.
• the cell converter 22X includes a current sensor (current transformer) 221, a cell converter main body 222, and a heat sink.
• the current sensor 221 detects the current flowing through the input terminals IN1, IN2, and IN3.
• the magnitude of this current is indicated by ix.
• x is an identifier that identifies the stage number and may be, for example, a natural number.
• FIG. 3B shows a configuration example in which the cell converter 22X is a combination of a diode converter 2221D and a two-level converter 222D (inverter 2222).
• the cell converter main body 222 shown in Figure 3B includes a three-phase input diode converter 2221D and a two-level converter 2222D in which the AC side potential on the output side changes in two stages.
• the diode converter 2221D and the two-level converter 2222D are connected on the DC side.
• An energy storage element such as a capacitor C1 is connected to the DC part.
• the configuration shown in Figure 3C is for receiving and converting single-phase AC power.
• the cell converter 22X has input terminals IN1 and IN2 and output terminals OUT1 and OUT2.
• the cell converter 22X includes a current sensor (current transformer) 221, a cell converter main body 222, and a heat sink.
• the current sensor 221 detects the current flowing between the input terminals IN1 and IN2.
• the magnitude of this current is indicated by ix.
• x is an identifier that identifies the stage number and may be, for example, a natural number.
• FIG. 3D shows an example in which the cell converter 22X is configured as a so-called two-level converter.
• 3D includes a two-level converter in which the AC side potential changes in two stages.
• the cell converter 22X has a single-phase converter on each of the input and output sides, and their DC sections are connected back to back to each other.
• An energy storage element such as a capacitor C1 is connected to the DC section.
• the above-described cell converter main body 222 is an example of a two-level converter, but is not limited to this and may be modified as appropriate, for example, it may be configured as a three-level converter in which the AC side potential changes in three stages.
• the configuration shown in FIG. 3F includes cascaded diode converters and an inverter 2222 configured as a three-level converter. In this way, various configurations can be applied depending on the application and capacity.
• 3B, 3D, and 3F employ insulated-gate bipolar transistors (IGBTs) as switching elements, but other switching elements may be used.
• IGBTs insulated-gate bipolar transistors
• other switching elements include metal-oxide-semiconductor field-effect transistors (MOSFETs), gate turn-off (GTO) thyristors, and gate commutated turn-off (GCT) thyristors.
• MOSFETs metal-oxide-semiconductor field-effect transistors
• GTO gate turn-off
• GCT gate commutated turn-off
• FWDs free-wheeling diodes
• 3A, 3C, and 3E may be configured as a circuit unit in which the converter 2221 and the inverter 2222 are separated.
• the capacitor C1 may be separate from the converter 2221 and the inverter 2222, or may be housed in either of the circuit units.
• the cell converter main body 222 may be configured by housing the converter 2221, the inverter 2222, and the capacitor C1 in a single circuit unit.
• the heat sink is configured to dissipate heat from the switching elements of the converter 2221 and the inverter 2222. As will be described later, a temperature sensor 28 is provided on the heat sink.
• FIGS 4A and 4B these figures explain the arrangement of each temperature sensor on the converter board 20 of the embodiment.
• Figures 4A and 4B are figures explaining the arrangement of each temperature sensor on the converter board 20 of the embodiment.
• the cell converter 22X is disposed in the housing 21 of the converter panel 20 shown in Figures 4A and 4B. Furthermore, each temperature sensor is disposed in the housing 21 of the power conversion device 1.
• the cooling fan 23 may be configured as follows. A case will be described in which the cooling fan 23 includes an exhaust-type fan unit. In this case, the cooling fan 23 is arranged, for example, to align with an opening on the top surface of the housing 21. An air intake is provided in a door or the like of the housing 21, and the air intake is equipped with a filter for removing dust and preventing insects. The cool air taken in through the air intake absorbs heat as it passes through the housing 21, and is exhausted to the outside of the housing 21 via the fan unit of the cooling fan 23.
• FIG. 5 is a configuration diagram of the controller 32 according to the embodiment.
• the controller 32 includes an arithmetic unit such as an MCU or FPGA, and its peripheral circuits.
• the arithmetic unit of the controller 32 includes a processor that executes processing using software (programs), or a hardware arithmetic circuit.
• the controller 32 includes a current detection unit 321, a current calculation unit 322, a heat sink temperature detection unit 323, a heat sink temperature calculation unit 324, temperature abnormality detection units 326 and 327, an abnormality state response processing unit 328, a control unit 329, a PWM output unit 330, an external command receiving unit 340, and a memory unit 350.
• the current detection unit 321 includes a conversion unit such as an AD (analog-to-digital) converter, and receives the signal output by the current detector 7 as input, converts that signal into current data for calculation, and outputs it to the current calculation unit 322.
• AD analog-to-digital
• the current calculation unit 322 receives the current data output by the current detection unit 321, calculates the effective value of the current based on the current data, and outputs the calculated value to the control unit 329.
• the heat sink temperature detection unit 323 includes a conversion unit such as an AD converter, and receives the signals output by each temperature sensor 28, converts them into temperature data for calculation, and outputs them to the heat sink temperature calculation unit 324.
• a conversion unit such as an AD converter
• the heat sink temperature calculation unit 324 receives the temperature data output by the heat sink temperature detection unit 323, calculates the temperature in degrees Celsius, for example, based on the temperature data, and outputs the result to the abnormal state response processing unit 328.
• the temperature abnormality detection unit 326 detects temperature abnormalities based on the detection results of the temperature sensors 24, 25.
• the temperature detection units 326A, 326B include a conversion unit such as an AD converter, and receive the signals output by the temperature sensors 24, 25, convert them into temperature data for calculation, and output them to the temperature calculation unit 326C.
• the temperature calculation unit 326C generates information indicating the temperature difference between the temperatures detected by the temperature sensors 24, 25, detects the occurrence of a temperature abnormality, and outputs the result to the abnormal state response processing unit 328.
• the temperature abnormality detection unit 327 detects temperature abnormalities based on the detection results of the temperature sensors 14, 15.
• the temperature detection units 327A, 327B include a conversion unit such as an AD converter, and receive the signals output by the temperature sensors 14, 15, convert them into temperature data for calculation, and output them to the temperature calculation unit 327C.
• the temperature calculation unit 327C generates information indicating the temperature difference between the temperatures detected by the temperature sensors 14, 15, detects the occurrence of a temperature abnormality, and outputs the result to the abnormal state response processing unit 328.
• the external command receiver 340 receives external command values used to control the electric motor 40, for example, from a higher-level device, and outputs them to the control unit 329.
• the storage unit 350 includes a storage medium such as a semiconductor memory or a magnetic storage device. New data is written to the storage unit 350 by a write process from the control unit 329, and the storage unit 350 stores this data.
• the storage unit 350 outputs the stored data by a read process from the control unit 329. Data may be written to the storage unit 350 by a dedicated controller instead of by the control unit 329.
• the control unit 329 performs various processes related to the collection and management of various data, control of the cell converter 22X, and identification of the state of the power conversion device 1.
• the abnormal condition response processing unit 328 is involved in collecting and managing various types of data, and performs the following processing.
• the abnormal condition response processing unit 328 acquires temperature abnormality information and internal housing temperature data detected by the temperature abnormality detection units 326 and 327, temperature data calculated by the heat sink temperature calculation unit 324, and current data calculated by the current calculation unit 322.
• the abnormal condition response processing unit 328 monitors the various types of data acquired.
• the abnormal condition response processing unit 328 writes and stores the results of this monitoring and the various types of data described above as time history data in the memory unit 350.
• the control unit 329 is involved in the control of the cell converter 22X and performs the following processing.
• the control unit 329 uses various data stored in the storage unit 350 or collected data to calculate a control amount (for example, a voltage reference) for PWM control of the electric motor 40 for each control period and outputs the calculated control amount to the PWM output unit 330.
• the control unit 329 may perform processing related to identifying the state of the power electronics device 1. For example, the control unit 329 may use information on the temperatures inside each housing (detection results of the temperature sensors 14, 24) from the collected temperature-related data to control the cell converter 22X, thereby making it possible to adjust the temperatures of the transformer 12 and the cell converter 22X.
• the PWM output unit 330 generates a PWM signal based on the control variable (voltage reference) supplied from the control unit 329 and outputs it to the cell converter 22X.
• FIG. 6 is a flowchart of the temperature monitoring process according to the embodiment.
• the controller 32 of the power conversion device 1 is connected to the above-mentioned temperature sensors and the like.
• the controller 32 detects the output signals of the temperature sensors, and periodically acquires temperature information from the output signals of the temperature sensors, for example, and uses the information in the temperature monitoring process.
• the controller 32 performs the temperature monitoring process for the power conversion device 1 in the following procedure.
• the controller 32 detects the output signals of the temperature sensors (S11).
• the controller 32 calculates the temperature difference ⁇ T (deviation) from the detection results of the intake temperature sensor and the exhaust temperature sensor (S12).
• the temperature difference ⁇ T includes either or both of the temperature difference between the temperatures detected by the temperature sensors 14 and 15 and the temperature difference between the temperatures detected by the temperature sensors 24 and 25.
• the controller 32 compares the temperature difference ⁇ T with a predetermined threshold temperature TTH1 (S13).
• the controller 32 determines that the temperature difference ⁇ T is within the range of normal temperature fluctuations, turns off a flag indicating the occurrence of a temperature abnormality, and determines the temperature of the cell converter 22X. For example, the controller 32 estimates the temperature THS of the heat sink of each of the cell converters 22X (S15), and compares the temperature THS of the heat sink of each of the cell converters 22X with a predetermined threshold temperature TTH2.
• the controller 32 determines that it is within the range of normal temperature fluctuations, keeps the flag indicating the occurrence of a temperature abnormality in its inverted state, and ends the series of processes.
• the controller 32 sets a flag indicating the occurrence of a temperature abnormality (S16). For example, in this case, it can be assumed that a condition has occurred that could be determined to be an abnormal condition that is not within the range of normal temperature fluctuations.
• the power conversion of the power converter 22 on the converter board 20 is stopped. More specifically, the switching elements that make up the power converter 22 are controlled to the off state by, for example, stopping the transmission of gate signals to those elements. This makes it possible to limit losses in the on state of the switching elements and the occurrence of switching losses. While residual heat from losses just before the above-mentioned off state can cause a temperature rise inside the housing, this temperature rise can be suppressed.
• the controller 32 may determine that an abnormality has occurred when the temperature difference between the temperature upwind of the cooling fan 13 and the temperature downwind of the cooling fan 13 exceeds a predetermined temperature difference (TTH1). The controller 32 may determine that an abnormality has occurred when the temperature difference between the temperature upwind of the cooling fan 23 and the temperature downwind of the cooling fan 23 exceeds a predetermined temperature difference (TTH1). Depending on the result of this determination, the controller 32 may stop the power converter 22 of the converter board 20 and then perform various processes for temperature protection.
• FIG. 7 is a diagram for explaining the temperature monitoring process according to the embodiment, and shows a timing chart illustrating an example of a model of a typical temperature change.
• the temperature sensors are arranged at the locations shown in FIG. 1 and other figures.
• the temperature difference between the intake section (temperature sensors 14, 24) and the exhaust section (temperature sensors 15, 25) of the cooling fan is monitored. If the cooling fan is running while the inverter is running, the temperature of the intake section 26 and the temperature of the exhaust section 27 will be roughly the same, and this temperature will generally be higher than the ambient temperature. Also, the temperature of the intake section 16 and the temperature of the exhaust section 17 will be roughly the same, and this temperature will generally be higher than the ambient temperature.
• the abnormal state processing unit 328 may use the temperature information acquired from the temperature sensors 14 , 24 , 28 , and 34 to control the rotation speed of the cooling fans 13 and 23 . This allows the abnormal condition response processor 328 to control the rotation speed of the cooling fans 13, 23 depending on the load (power consumption of the electric motor 40, required torque, etc.). For example, by controlling the rotation speed of the cooling fans 13, 23 to be set higher when internal loss is relatively large, and to be set lower when internal loss is relatively small, it becomes possible to reduce the power required to operate the cooling fans. This can also be expected to have an effect in terms of energy conservation.
• the power conversion device 1 is a device that houses a heat generating element that generates heat when current is applied within its own housing, and that forcibly cools the inside of the housing using a fan (cooling fan) provided in the housing.
• the first temperature sensor is a temperature sensor disposed upwind of the fan in the flow of air generated by the fan and detects the temperature upwind of the fan.
• the second temperature sensor is a temperature sensor disposed downstream of the fan in the flow of air generated by the fan and detects the temperature downstream of the fan.
• the control unit detects a decrease in air volume using the temperature difference between the temperature upwind of the fan and the temperature downwind of the fan. This makes it possible to identify the actual state of air generated by the fan and further increase the reliability of thermal protection of a power conversion device that performs forced cooling using a fan.
• the temperature abnormality detection method of this embodiment can indirectly detect the airflow rate generated by the fan, making it possible to detect events caused by factors other than fan failure.
• the heating element provided in the device may include a transformer or power converter.
• the first temperature sensor is disposed above a heat generating element such as a transformer, a power converter, etc. By disposing the first temperature sensor in such a position, it becomes easier to detect heat generated by the heat generating element.
• the device accommodates a heat-generating element that generates heat when power is applied within its own housing, and uses a fan provided in the housing to forcibly cool the interior of the housing.
• the device includes a first temperature sensor, a second temperature sensor, and a control unit.
• the first temperature sensor is a temperature sensor positioned upwind of the fan in the airflow generated by the fan, and detects the temperature upwind of the fan.
• the second temperature sensor is a temperature sensor positioned downstream of the fan in the airflow generated by the fan, and detects the temperature downstream of the fan.
• the control unit detects a decrease in air volume using the temperature difference between the temperature upwind of the fan and the temperature downwind of the fan. This can further increase the reliability of temperature protection in devices that use a fan to perform forcible cooling.
• the controller 32 includes, for example, a memory unit, a CPU (central processing unit), a drive unit, and an acquisition unit.
• the memory unit, CPU, drive unit, and acquisition unit are connected within the control unit, for example, via a BUS.
• the memory unit includes semiconductor memory.
• the CPU includes a processor that executes desired processing in accordance with a software program.
• the drive unit generates control signals for each component of the power conversion device 1 under the control of the CPU.
• the acquisition unit acquires the detection results of each current sensor and voltage sensor. For example, the CPU of the controller 32 controls the main circuit of each phase using the drive unit based on the detection results of the current and voltage sensors acquired by the acquisition unit.
• the controller 32 may perform some or all of its processing through software program processing as described above, or alternatively, may perform it using hardware.
• the controller 32 may also be configured by dividing it as appropriate, thereby ensuring circuit insulation.
• the configuration of the power converter 22 described above controls the on/off of switching elements contained in the cell converter 22U1, etc., but is not limited to this and may also be applied to the configuration of a power converter (converter, inverter) that converts DC power and AC power, etc.
• the configuration of the transformer 12 can be determined appropriately depending on the available power supply conditions, the rated capacity of the load, the specifications of the power converter 22, etc. In this case, the transformer 12 may be configured by combining transformers with standard configurations specified by JIS, IEC, etc.

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• 2024
  • 2024-05-13 JP JP2025530040A patent/JPWO2025238679A1/ja active Pending
  • 2024-05-13 WO PCT/JP2024/017612 patent/WO2025238679A1/ja active Pending

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