JP2010193695A - Power converter and method for detecting fan failure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent abnormal temperature rise in the power converter of a closed structure due to stoppage of a fan used to cool by subjecting inside air to forced circulation. <P>SOLUTION: The power converter is equipped with a temperature-monitoring circuit 20 to detect air temperature inside a housing 15, and to check whether the air temperature is abnormal; and a controlling circuit 13 to regulate the output of an apparatus, when abnormity is detected in the air temperature by the temperature-monitoring circuit 20. The control circuit 13 controls to stop or reduce the output of the apparatus, when the air temperature inside the housing rises due to stoppage of a fan 18 during operation of the power converter, and the temperature-monitoring circuit 20 detects the abnormity of the air temperature. As a result, the amount of heat generation is suppressed in heat-generating components, and the air temperature is reduced inside the housing 15. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a power conversion device and a fan failure detection method thereof, and in particular, has a cooling fin thermally connected to a cooling body that cools a power device installed inside a sealed housing, and the cooling fin The present invention relates to a closed-type power converter that cools air inside a casing by circulating air inside the casing and a fan failure detection method thereof.

  The power conversion device includes a power device, and converts the alternating current into direct current or alternating current, or converts direct current into direct current or alternating current by switching the power device. Since the power device generates heat during the switching operation, it is necessary to transport such heat to the outside of the casing of the power converter and cool it.

  The power device drive circuit and its control circuit are composed of electronic components, and are housed in a housing together with a power device that generates heat. In order for electronic components to operate stably, the ambient temperature of the electronic components must be kept within the operating temperature range recommended by the device manufacturer. This is because when the ambient temperature of the electronic component becomes equal to or higher than the recommended ambient temperature, the power conversion device malfunctions and eventually the device fails.

  In a power converter, a configuration is known in which the power device radiates heat and at the same time efficiently cools the ambient temperature of the electronic component, that is, the air temperature inside the housing (see, for example, Patent Document 1).

  According to Patent Document 1, a cooling body for liquid cooling is provided inside a sealed casing, and a power device is mounted on the cooling body. The heat of the power device is led to the outside of the housing by the liquid circulating in the cooling body, and is dissipated to the outside of the housing of the power converter by being cooled by the radiator and fan installed outside, thereby generating heat The connected power device is cooled.

  On the other hand, if the air inside the closed power conversion device has a temperature higher than the air temperature outside the housing due to heat generated by the electronic components, the heat inside the housing penetrates the cover and the housing Heat is naturally dissipated and cooled by the heat passing phenomenon transmitted to the outside. However, the amount of heat released by this heat passage is generally small. Therefore, the air inside the casing of the power converter is circulated by a fan, and the circulating air is applied to the cooling fins that are thermally connected to the cooling body. As a result, the heat dissipated in the air by the heat generating electronic component is once collected by the cooling fins, and the heat is transferred to the cooling body of the power device and further dissipated from the cooling body to the outside of the power converter. become. As a result, the air temperature inside the casing of the power converter is cooled and does not exceed the recommended ambient temperature of the electronic component.

  In the case of such an internal air cooling system using a power converter, the cooling fins can collect heat inside the housing and transfer it to the cooling body of the power device. Is high.

JP 2008-60515 A

  However, the fan that circulates the air inside the casing may stop suddenly due to loss of the drive power supply, and may stop due to stress due to the life or usage environment. In such a case, the cooling fin However, there is a problem that the temperature inside the casing may become higher than the recommended ambient temperature of the electronic component because the heat inside the casing cannot be collected.

  FIG. 18 is a diagram showing a change in the air temperature in the power converter when the fan is stopped. According to FIG. 18, when the power conversion device starts operation, the fan starts operation in conjunction with this, and the power conversion device supplies a predetermined output. As the power converter continues to operate, the air temperature in the power converter increases, but the temperature does not exceed the recommended ambient temperature of the electronic component.

  Here, if the fan stops due to a failure, only heat is released from the surface of the housing, and most of the heat that is dissipated to the air by the heat generating components inside the housing cannot be dissipated outside the device. The temperature rises in a short time. The final value of the air temperature inside the housing is a temperature at which the amount of heat generated inside matches the amount of heat released. Thus, if the air temperature inside the housing rises and exceeds the allowable operating temperature of the electronic component, the electronic component will malfunction.

  The present invention has been made in view of these points, and an object of the present invention is to provide a closed-type power conversion device that can cope with an abnormal temperature rise of air in a casing due to a fan stop.

  In the present invention, in order to solve the above-described problem, the power device inside the housing is cooled by the cooling body, and the fan circulates and flows the air inside the housing to the cooling fin thermally connected to the cooling body. In a closed-type power converter that cools the air inside the housing, a temperature monitoring unit that detects an abnormality in the air temperature inside the housing, and a device output in response to the detection of the air temperature abnormality by the temperature monitoring unit And a control unit that restricts the power conversion device.

  According to such a power conversion device, the temperature monitoring unit monitors the air temperature inside the housing, and when an abnormality in the air temperature is detected, the control unit operates to limit the device output. Thereby, since the calorific value of the heat-generating component radiated into the air inside the housing is reduced, the air temperature inside the housing can be lowered.

  The power converter configured as described above detects an abnormality in the air temperature and restricts the output of the device. Therefore, the fan breaks down and heat collection of the air inside the housing and heat transfer to the cooling body cannot be performed. Even if the temperature rises abnormally, the amount of heat generated by the heat-generating components can be reduced by limiting the output of the device, so that the air temperature inside the housing can be lowered reliably, preventing malfunctions due to abnormally high temperatures. There is an advantage that you can. Moreover, it becomes possible to continue an operation | movement, without stopping a power converter device completely by controlling so that an apparatus output may be reduced at the time of temperature abnormality detection.

It is a figure which shows the structural example of the power converter device which concerns on 1st Embodiment. It is a circuit diagram which shows the structural example of an air temperature abnormality detection circuit. It is a circuit diagram which shows the modification of an air temperature abnormality detection circuit. It is a circuit diagram which shows the structural example of a control circuit and an air temperature monitoring circuit. It is explanatory drawing which shows the operation example of the power converter device by the circuit of FIG. It is a circuit diagram which shows the modification of a control circuit and an air temperature monitoring circuit. It is explanatory drawing which shows the operation example of the power converter device by the circuit of FIG. It is explanatory drawing which shows another example of operation | movement of the power converter device by the circuit of FIG. It is a figure which shows the structural example of the power converter device which concerns on 2nd Embodiment. It is a circuit diagram which shows the structural example of the temperature monitoring circuit of the power converter device which concerns on 2nd Embodiment. It is a circuit diagram which shows the modification of the temperature monitoring circuit of the power converter device which concerns on 2nd Embodiment. It is a circuit diagram which shows the structural example of a control circuit and a drive circuit. It is explanatory drawing which shows the operation example of the power converter device by the circuit of FIG. It is a circuit diagram which shows the modification of a control circuit and a drive circuit. It is explanatory drawing which shows the operation example of the power converter device by the circuit of FIG. It is a circuit diagram which shows the further modification of a control circuit and a drive circuit. It is explanatory drawing which shows the operation example of the power converter device by the circuit of FIG. It is a figure which shows the change of the air temperature in a power converter device at the time of a fan stop.

  Hereinafter, with respect to the embodiments of the present invention, a closed type in which air inside a housing is circulated through cooling fins thermally connected to a cooling body that cools a power device inside the housing to cool the air inside the housing. A case where the present invention is applied to the power conversion apparatus will be described in detail with reference to the drawings.

FIG. 1 is a diagram illustrating a configuration example of the power conversion device according to the first embodiment.
The power conversion apparatus includes a power device 11 that converts power, a drive circuit 12 that drives the power device 11, and a control circuit 13 that controls the entire apparatus including the drive circuit 12 (control in claims) Part corresponding). The power device 11 is mounted in a state of being thermally coupled to a liquid cooling type cooling body 14. Although not shown, the cooling body 14 is connected to one end of two pipes for circulating the coolant. These pipes pass through the casing 15 and are led to the outside of the power conversion device. A pump and a radiator are connected to the other end, and a fan for forced air cooling is installed in the radiator. A cooling system is configured.

  The casing 15 has a closed structure and constitutes a closed type power converter, and a passage for circulating the air 16 is formed therein, and a cooling fin 17 and a fan 18 are installed in the passage. Yes. The cooling fin 17 is thermally connected to the cooling body 14 that cools the power device 11 by, for example, a heat pipe 19. As a result, the air 16 inside the casing 15 is forcibly circulated by the fan 18, and when the circulating air 16 passes through the cooling fins 17, the cooling fins 17 collect the heat of the air 16 to power the power device. Heat is transferred to the 11 cooling bodies 14 to cool the air 16.

  This power conversion device includes a temperature monitoring circuit 20 (corresponding to a temperature monitoring unit in claims) that controls the air temperature inside the housing 15. The temperature monitoring circuit 20 includes an air temperature detection circuit 22 that receives the detection output of an air temperature detection sensor 21 installed in the vicinity of the heat generating component, and an air temperature abnormality detection that receives the output of the air temperature detection circuit 22. Circuit 23. The output of the air temperature abnormality detection circuit 23 is connected to the control circuit 13.

  Thereby, in the temperature monitoring circuit 20, the air temperature detection circuit 22 calculates the air temperature inside the housing 15 based on the detection signal of the air temperature detection sensor 21. The air temperature abnormality detection circuit 23 detects an air temperature abnormality from the output of the air temperature detection circuit 22. The air temperature abnormality detection circuit 23 outputs nothing if there is no abnormality in the air temperature, and outputs an alarm signal indicating an abnormality in the air temperature to the control circuit 13 if it detects an abnormally high air temperature. When the control circuit 13 receives an air temperature abnormality alarm signal from the air temperature abnormality detection circuit 23, the control circuit 13 controls the output of the power conversion device to be zero (operation stop) or limited to a predetermined value. As a result, the heat generation amount of the heat generating component is eliminated or suppressed to a small heat generation amount, so that the air temperature inside the housing 15 can be lowered.

Next, a configuration example of the air temperature abnormality detection circuit 23 in the temperature monitoring circuit 20 will be described.
FIG. 2 is a circuit diagram showing a configuration example of an air temperature abnormality detection circuit. In FIG. 2, the same or equivalent components as those shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The air temperature abnormality detection circuit 23 shown in FIG. 2 has a comparator 24 and an air temperature abnormality detection value setting circuit 25. The comparator 24 has one input connected to the output of the air temperature detection circuit 22 and the other input connected to the output of the air temperature abnormality detection value setting circuit 25. The air temperature abnormality detection value setting circuit 25 is set in advance so as to output a value corresponding to the temperature detected that the air temperature is abnormal. The temperature at which this air temperature abnormality is detected is determined, for example, based on the maximum ambient temperature recommended by the device manufacturer or based on the maximum ambient temperature allowed by the built-in power device 11 or other electrical components. ing. Therefore, the air temperature detection sensor 21 is installed in the vicinity of an electronic component or a heat generating component such as the power device 11.

  The air temperature abnormality detection circuit 23 configured as described above has an air temperature inside the housing 15 detected by the air temperature detection sensor 21 by the comparator 24 and a predetermined value determined by the air temperature abnormality detection value setting circuit 25. Are compared, and when the air temperature does not reach a predetermined value, a signal indicating that the air temperature is abnormal is not output. When the air temperature inside the housing 15 rises to a predetermined value or more, the comparator 24 detects an air temperature abnormality and outputs an air temperature abnormality signal.

  It should be noted that the functions of the air temperature detection circuit 22 and the air temperature abnormality detection circuit 23 in the temperature monitoring circuit 20 can be realized by using a part of the functions of a microcomputer constituting the control circuit 13, for example. In this case, the detection of the air temperature abnormality is performed by periodically sampling the air temperature with a microcomputer and determining that the sampled value is equal to or higher than a predetermined temperature.

  FIG. 3 is a circuit diagram showing a modification of the air temperature abnormality detection circuit. In FIG. 3, the same or equivalent components as those shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The air temperature abnormality detection circuit 23 shown in FIG. 3 includes a comparator 24, an air temperature increase rate detection circuit 26, and an air temperature increase rate abnormality detection value setting circuit 27. The comparator 24 has one input connected to the output of the air temperature rise rate detection circuit 26, and the other input connected to the output of the air temperature rise rate abnormality detection value setting circuit 27. The air temperature rise rate detection circuit 26 receives the air temperature detected by the air temperature detection circuit 22 and outputs the rate of change of the air temperature per unit time. The air temperature increase rate abnormality detection value setting circuit 27 outputs a temperature increase rate corresponding to an abnormal increase in air temperature in a short time.

  The function of the air temperature abnormality detection circuit 23 can be realized by a microcomputer, for example. In that case, the air temperature abnormality is detected by periodically sampling the air temperature with a microcomputer and judging that the temperature rise value within a predetermined time of the sampled value is equal to or higher than a predetermined temperature rise value. Do.

  The air temperature abnormality detection circuit 23 can cope with a case where the abnormal rise in the air temperature inside the housing 15 is slow by combining the structure shown in FIG. 2 and the structure shown in FIG. .

Next, a configuration example of the control circuit 13 and the temperature monitoring circuit 20 and an operation example of the control circuit 13 when the temperature monitoring circuit 20 detects an air temperature abnormality will be described.
FIG. 4 is a circuit diagram showing a configuration example of the control circuit and the air temperature monitoring circuit, and FIG. 5 is an explanatory diagram showing an operation example of the power conversion device using the circuit of FIG. In FIG. 4, the same or equivalent components as those shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The control circuit 13 includes an operation command output circuit 28 that sends out an operation command for the power conversion device, and a gate circuit 29. The gate circuit 29 has an output of the operation command output circuit 28 connected to its positive logic input, and an output of the temperature monitoring circuit 20 connected to its negative logic input. Is taken as an operation command for the power converter.

  According to this control circuit 13, in a normal state where the temperature monitoring circuit 20 has not detected an air temperature abnormality, the gate circuit 29 permits the operation command from the operation command output circuit 28, and puts the power converter into the operation state. . In this operating state, the fan 18 is also operated, the power conversion device is maintained at a predetermined output value, and the air temperature inside the power conversion device is kept below a predetermined temperature.

  Here, as shown in FIG. 5, it is assumed that the operation of the fan 18 is stopped for some reason during the operation. As a result, heat collection by the cooling fins 17 is not performed inside the housing 15, so that the air temperature in the power converter increases rapidly. When the temperature monitoring circuit 20 detects an air temperature abnormality and outputs an air temperature abnormality signal, the gate circuit 29 prohibits the operation command from the operation command output circuit 28, and the control circuit 13 stops the operation of the power converter. At this time, the output command value of the power converter is also set to zero by the control circuit 13. When the operation of the power converter is stopped, heat dissipation from the heat-generating component to the air in the power converter is eliminated, so that the increase in the air temperature in the power converter is stopped and the temperature is decreased.

  FIG. 6 is a circuit diagram showing a modification of the control circuit and the air temperature monitoring circuit, and FIG. 7 is an explanatory diagram showing an operation example of the power conversion device using the circuit of FIG. In FIG. 6, the same or equivalent components as those shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The control circuit 13 includes an output command circuit 30 that outputs an output command value of the power conversion device, a limiter circuit 31, and an output limit value calculation circuit 32. The output limit value calculation circuit 32 has an input connected to the output of the air temperature abnormality detection circuit 23 of the temperature monitoring circuit 20, and an output connected to the output control input of the limiter circuit 31. The limiter circuit 31 is connected to the output of the output command circuit 30.

  According to the control circuit 13, the output limit value calculation circuit 32 sets the upper limit value of the limiter circuit 31 to the maximum in a normal state in which the temperature monitoring circuit 20 does not detect an abnormal air temperature. As a result, the output command value output from the output command circuit 30 becomes the output command value of the control circuit 13 without being limited by the limiter circuit 31. In this operating state, the fan 18 is also operated, the power conversion device is maintained at a predetermined output value, and the air temperature inside the power conversion device is kept below a predetermined temperature.

  Here, assuming that the operation of the fan 18 is stopped, as shown in FIG. 7, heat collection by the cooling fins 17 is not performed inside the housing 15, so that the air temperature in the power converter increases rapidly. . When the temperature monitoring circuit 20 detects an air temperature abnormality and outputs an air temperature abnormality signal, the output limit value calculation circuit 32 calculates a predetermined output limit value and outputs it to the limiter circuit 31. The limiter circuit 31 reduces the output command value output from the output command circuit 30 to the output limit value calculated by the output limit value calculation circuit 32 and outputs it as the output command value of the control circuit 13. Thereby, even if the power converter encounters a situation where the fan inevitably suddenly stops, the operation is continued in a state where the output is lowered to a predetermined value. As the device output is reduced, the temperature of the air in the power conversion device stops increasing and reaches a temperature corresponding to the device output.

  As a method for limiting the output, a multiplier is provided in place of the limiter circuit 31 that limits the output of the output command circuit 30, and the output of the output command circuit 30 is limited by a predetermined coefficient. Also good.

FIG. 8 is an explanatory diagram showing another example of the operation of the power conversion apparatus using the circuit of FIG.
The operation of the power conversion device shown in FIG. 8 is to limit the device output according to the air temperature in the power conversion device. Therefore, when the air temperature abnormality detection circuit 23 sends the air temperature abnormality signal to the output limit value calculation circuit 32, the temperature monitoring circuit 20 uses the detected air temperature in addition to the signal indicating whether the air temperature is abnormal. A signal to represent is also sent. The output limit value calculation circuit 32 receives the air temperature abnormality signal and the air temperature signal from the air temperature abnormality detection circuit 23, and calculates the upper limit value of the output command value according to the air temperature. The limiter circuit 31 reduces the output command value output from the output command circuit 30 to the upper limit value calculated by the output limit value calculation circuit 32 and outputs it as the output command value of the control circuit 13. As a result, the power conversion device will continue to operate by dynamically reducing the device output so that the internal air temperature does not exceed a predetermined value, and even if the fan stops, the power conversion device is completely So that it will not be shut down.

FIG. 9 is a diagram illustrating a configuration example of the power conversion device according to the second embodiment.
A power conversion device converts a direct current or alternating current power source into direct current or alternating current and outputs it. For example, a power supply device that supplies direct current or single-phase or three-phase alternating current power, or single-phase or three-phase alternating current It can be set as the inverter apparatus which outputs electric power and drives an electric motor. As the power device 11 of such a power converter, for example, an IGBT (Insulated Gate Bipolar Transistor) is used to constitute an inverter circuit that converts power. A drive circuit 12 is connected to the power device 11, and this drive circuit 12 is connected to be controlled by a control circuit 13 that controls the entire apparatus.

  The power device 11 is mounted on a cooling body 14 that absorbs heat generated by these devices. The cooling body 14 is piped to a radiator 40 installed outside the power converter, and is configured so that the refrigerant circulates by a pump 41 provided in the middle of the pipe. Thereby, the heat generated by energizing the power device 11 is transferred to the outside of the apparatus by the refrigerant circulating through the cooling body 14 and is radiated by the radiator 40.

  The cooling body 14 is thermally connected to cooling fins 17 disposed inside the housing 15. The cooling fins 17 are disposed in an air passage through which air inside the casing 15 is forcibly circulated by the fans 18, and collect the heat of the air when the circulating air passes. The heat collected by the cooling fins 17 is transferred to the cooling body 14. This is because the temperature of the cooling body 14 is always kept lower than the internal air temperature of the housing 15 by controlling the temperature of the circulating refrigerant and the amount of the circulating refrigerant with respect to the loss generated by the power device 11. This is because the route of the heat flow from the air inside the casing 15 to the cooling body 14 through the cooling fins 17 is formed.

  In this power conversion device, the power consumed by the drive circuit 12 and the control circuit 13 and the loss generated by the current flowing through the power device 11 and the main circuit conductor and other parts are radiated as heat into the housing 15. The radiated heat is once absorbed by the cooling fins 17 as the internal air circulates in the apparatus by the operation of the fan 18, and the heat is moved to the cooling body 14 of the power device 11. The heat can be radiated from the device 14 by the radiator 40 outside the device.

  Further, in such a closed type power conversion device, a heat quantity proportional to the temperature difference between the internal and external air and the surface area of the device passes through the surface member of the device and moves to the outside. However, the amount of heat released by this heat passage is smaller than the amount of heat collected by the cooling fins 17. As described above, most of the heat radiated to the inside of the casing 15 is exhausted to the outside of the apparatus, so that the rise in the air temperature inside the casing 15 is moderate.

  When the fan 18 stops due to a failure, heat dissipation to the outside of the apparatus is limited to that performed from the surface of the apparatus, and this heat dissipation amount is equal to the heat absorbed by the cooling fins 17 when the fan 18 is operating. Compared to relatively few. Therefore, most of the heat radiated to the air by the heat-generating component in the apparatus cannot be radiated to the outside of the apparatus, and the air temperature in the apparatus rapidly rises in a short time. The internal air temperature rises until the amount of heat generated inside matches the amount of heat radiated from the surface of the device.

  In addition, the power conversion device includes a temperature monitoring circuit 20 that monitors the temperature inside the housing 15. The temperature monitoring circuit 20 includes an air temperature detection sensor 21 that detects the air temperature inside the housing 15, and cooling. A cooling body temperature detection sensor 42 for detecting the temperature of the body 14 is connected. The temperature monitoring circuit 20 monitors changes in the temperature of the air inside the casing 15 and the temperature of the cooling body 14, and when the temperature of the air inside the casing 15 shows an abnormality while the temperature of the cooling body 14 is normal Then, it is determined that the fan 18 has failed, and a fan failure signal is output to the control circuit 13. When receiving the fan failure signal, the control circuit 13 controls to limit the device output.

  Here, the air temperature detection sensor 21 that detects the air temperature and the cooling body temperature detection sensor 42 that detects the temperature of the cooling body 14 can be constituted by a resistance temperature detector, a thermocouple, a semiconductor temperature sensor, or the like.

Next, specific configuration examples of the temperature monitoring circuit 20, the drive circuit 12, and the control circuit 13 will be described.
FIG. 10 is a circuit diagram illustrating a configuration example of the temperature monitoring circuit of the power conversion device according to the second embodiment. 10, the same or equivalent components as those shown in FIGS. 2 and 9 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The temperature monitoring circuit 20 includes an air temperature detection circuit 22, a cooling body temperature detection circuit 43, and a fan failure detection circuit 44. The fan failure detection circuit 44 includes a comparator 24, an air temperature abnormality detection value setting circuit 25, a comparator 45, a cooling body temperature abnormality detection value setting circuit 46, and a gate circuit 47. The comparator 24 has one input connected to the output of the air temperature detection circuit 22 and the other input connected to the output of the air temperature abnormality detection value setting circuit 25. The comparator 45 has one input connected to the output of the cooling body temperature detection circuit 43 and the other input connected to the output of the cooling body temperature abnormality detection value setting circuit 46. The output of the comparator 24 is connected to the positive logic input of the gate circuit 47, and the output of the comparator 45 is connected to the negative logic input of the gate circuit 47.

  When the air temperature inside the casing 15 detected by the air temperature detection sensor 21 is lower than the first predetermined value set by the air temperature abnormality detection value setting circuit 25, the comparator 24 outputs a signal of logic “0”. When the air temperature inside the housing 15 becomes equal to or higher than the first predetermined value, a signal of logic “1” is output.

The first predetermined value set by the air temperature abnormality detection value setting circuit 25 is set to, for example, an upper limit value of the temperature at which the electronic component or the like operates stably.
The comparator 45 outputs a signal of logic “0” when the temperature of the cooling body 14 detected by the cooling body temperature detection sensor 42 is equal to or lower than the second predetermined value set by the cooling body temperature abnormality detection value setting circuit 46. When the temperature of the cooling body 14 becomes higher than the second predetermined value, a logic “1” signal is output.

  The second predetermined value set by the cooling body temperature abnormality detection value setting circuit 46 is higher than the maximum cooling body temperature in the apparatus operating condition, for example, the temperature of the cooling body 14 when the apparatus is operating at the maximum output. High temperature is set. As a result, the temperature of the cooling body 14 is increased due to another factor, which prevents erroneous detection in the case where the temperature of the cooling body 14 increases.

  The gate circuit 47 has a logic “1” when the air temperature inside the closed power converter is equal to or higher than a first predetermined value and the temperature of the cooling body 14 for cooling the power device 11 is equal to or lower than a second predetermined value. Is output. Thus, the fan failure detection circuit 44 determines that the fan has failed when the air temperature becomes abnormally high despite the cooling body 14 being normally cooled, and sends a fan failure signal to the control circuit 13. Will be output.

  Each function of the temperature monitoring circuit 20 can be realized by using a part of the function of the microcomputer constituting the control circuit 13, for example. In this case, the detection outputs of the air temperature detection sensor 21 and the cooling body temperature detection sensor 42 are converted from analog to digital, and the digital values are sampled and detected by a microcomputer. The air temperature abnormality and the cooling body temperature abnormality are detected by determining that the sampled value is equal to or higher than a predetermined temperature by a microcomputer.

  FIG. 11 is a circuit diagram showing a modification of the temperature monitoring circuit of the power conversion device according to the second embodiment. In FIG. 11, the same or equivalent components as those shown in FIGS. 3 and 9 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The temperature monitoring circuit 20 includes an air temperature detection circuit 22, a cooling body temperature detection circuit 43, and a fan failure detection circuit 44. The fan failure detection circuit 44 includes a comparator 24, an air temperature increase rate detection circuit 26, an air temperature increase rate abnormality detection value setting circuit 27, a comparator 45, a cooling body temperature increase rate detection circuit 48, and a cooling body. A temperature rise rate abnormality detection value setting circuit 49 and a gate circuit 47 are provided. The comparator 24 has one input connected to the output of the air temperature rise rate detection circuit 26, and the other input connected to the output of the air temperature rise rate abnormality detection value setting circuit 27. The comparator 45 has one input connected to the output of the cooling body temperature rise rate detection circuit 48 and the other input connected to the output of the cooling body temperature rise rate abnormality detection value setting circuit 49. The output of the comparator 24 is connected to the positive logic input of the gate circuit 47, and the output of the comparator 45 is connected to the negative logic input of the gate circuit 47.

  When the air temperature increase rate inside the housing 15 detected by the air temperature detection sensor 21 is lower than the first predetermined value set by the air temperature increase rate abnormality detection value setting circuit 27, the comparator 24 is logic " A signal of “0” is output, and a signal of logic “1” is output when the rate of increase in the air temperature inside the housing 15 becomes equal to or higher than the first predetermined value.

  The first predetermined value set by the air temperature increase rate abnormality detection value setting circuit 27 is higher than the maximum temperature increase rate of the internal air when the fan 18 for circulating the air in the apparatus is operating normally. Is set to

  When the temperature increase rate of the cooling body 14 detected by the cooling body temperature detection sensor 42 is equal to or less than the second predetermined value set by the cooling body temperature increase rate abnormality detection value setting circuit 49, the comparator 45 outputs a logic “0”. When the temperature rise rate of the cooling body 14 becomes higher than the second predetermined value, a logic “1” signal is output.

  The second predetermined value set by the cooling body temperature rise rate abnormality detection value setting circuit 49 is the highest cooling body temperature rise rate in the apparatus operating condition, for example, the cooling body 14 when the apparatus is operating at the maximum output. The temperature rise rate is set to a higher rise rate. This prevents erroneous detection in the case where the temperature of the cooling body 14 suddenly increases due to another factor, which affects the increase in air temperature.

  The gate circuit 47 has an air temperature increase rate inside the closed type power conversion device that is equal to or higher than a first predetermined value, and a temperature increase rate of the cooling body 14 that cools the power device 11 is equal to or lower than a second predetermined value. , A logic “1” signal is output. Thereby, the fan failure detection circuit 44 determines that the fan has failed when the air temperature rise rate becomes abnormal although the cooling body 14 is normally cooled, and sends a fan failure signal to the control circuit 13. Will be output.

  Each function of the temperature monitoring circuit 20 can be realized by using a part of the function of the microcomputer constituting the control circuit 13, for example. In this case, the detection outputs of the air temperature detection sensor 21 and the cooling body temperature detection sensor 42 are converted from analog to digital, and the digital values are sampled and detected by a microcomputer at a constant period. By taking the deviation between the data sampled at a fixed period, the rate of temperature rise can be obtained and compared with the second predetermined value set by the cooling body temperature rise rate abnormality detection value setting circuit 49. The air temperature rise rate abnormality can be detected.

  FIG. 12 is a circuit diagram showing a configuration example of the control circuit and the drive circuit, and FIG. 13 is an explanatory diagram showing an operation example of the power conversion device using the circuit of FIG. In FIG. 12, the same or equivalent components as those shown in FIGS. 4 and 9 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The control circuit 13 has an operation command output circuit 28 that sends out an operation command for the power converter, a gate circuit 29, and an output command calculation circuit 50 that calculates an output command value. The gate circuit 29 has the positive logic input connected to the output of the operation command output circuit 28 and the negative logic input connected to the output of the temperature monitoring circuit 20. Therefore, the gate circuit 29 takes the logical product of the operation command for the power conversion device and the fan failure signal and uses it as the operation command for the power conversion device. The drive circuit 12 has a PWM (Pulse Width Modulation) modulation circuit 51. The PWM modulation circuit 51 receives the operation command from the gate circuit 29 and the output command from the output command calculation circuit 50, and generates a control gate signal for the power device 11 constituting the inverter circuit, for example. Yes.

  According to the control circuit 13, in a normal state where the temperature monitoring circuit 20 does not output a fan failure signal, the gate circuit 29 permits the operation command from the operation command output circuit 28 and outputs it to the PWM modulation circuit 51. The PWM modulation circuit 51 receives an output command from the output command calculation circuit 50, and outputs a gate signal that maintains the corresponding device output. At this time, the fan 18 is operated normally, and the air temperature inside the power converter is kept below a predetermined temperature. That is, the air temperature inside the power conversion device gradually rises from the start of the device operation, and the internal heat generation amount and the heat radiation amount are balanced.

  Here, as shown in FIG. 13, it is assumed that the operation of the fan 18 is stopped for some reason during the operation. As a result, heat collection by the cooling fins 17 is not performed inside the housing 15, so that the air temperature in the power conversion device rises rapidly. When the temperature monitoring circuit 20 detects an air temperature abnormality and outputs a fan failure signal, in the control circuit 13, the gate circuit 29 prohibits the operation command from the operation command output circuit 28, and the PWM modulation circuit 51 detects the power device 11. To output a gate-off command to stop the operation of the power converter. Thereby, the output of a power converter device is restrict | limited to zero. Since the power conversion device stops operating, heat dissipation from the heat-generating component to the air in the power conversion device is eliminated, so that the air temperature in the power conversion device does not increase and gradually decreases.

  FIG. 14 is a circuit diagram showing a modification of the control circuit and the drive circuit, and FIG. 15 is an explanatory diagram showing an operation example of the power conversion device using the circuit of FIG. In FIG. 14, the same or equivalent components as those shown in FIGS. 6, 9 and 12 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The control circuit 13 includes an operation command output circuit 28 that sends an operation command for the power converter, an output command calculation circuit 50 that outputs an output command value for the power converter, a limiter circuit 31, and an output limit value calculation circuit 32. have. The output limit value calculation circuit 32 is connected to the output of the temperature monitoring circuit 20 at its input, and the output is connected to the output control input of the limiter circuit 31. The limiter circuit 31 is connected to the output of the output command calculation circuit 50. The drive circuit 12 has a PWM modulation circuit 51. The PWM modulation circuit 51 receives the operation command from the operation command output circuit 28 and the output command from the output command calculation circuit 50 and generates a control gate signal for the power device 11.

  According to the control circuit 13, the output limit value calculation circuit 32 sets the upper limit value of the limiter circuit 31 to the maximum in a normal state where the temperature monitoring circuit 20 has not detected a fan failure. As a result, the output command value output from the output command calculation circuit 50 is input to the PWM modulation circuit 51 without being limited by the limiter circuit 31. In this operating state, the fan 18 is operated, the power conversion device is maintained at a predetermined output value, and the air temperature inside the power conversion device is kept below a predetermined temperature.

  Here, assuming that the operation of the fan 18 is stopped, as shown in FIG. 15, heat collection by the cooling fins 17 is not performed inside the housing 15, so that the air temperature in the power converter increases rapidly. . At this time, the operation command from the operation command output circuit 28 is continued as it is. When the temperature monitoring circuit 20 detects an air temperature abnormality and outputs a fan failure signal, the output limit value calculation circuit 32 calculates a predetermined output limit value and outputs it to the limiter circuit 31. The limiter circuit 31 reduces the output command value output from the output command calculation circuit 50 to the output limit value calculated by the output limit value calculation circuit 32, and inputs it to the PWM modulation circuit 51. The PWM modulation circuit 51 performs pulse width modulation with the limited output command value, so that the power converter operates with a reduced output. Thus, even if the power converter encounters a situation where the fan 18 inevitably suddenly stops, the operation is continued in a state where the output is lowered to a predetermined value. Since the device output is reduced, the current flowing through the power device 11 and the conductor is reduced, the amount of heat released to the inside of the device is reduced, and the increase in the air temperature in the power conversion device is suppressed. The air temperature in the power conversion device is a temperature corresponding to the output of the device.

  FIG. 16 is a circuit diagram showing a further modification of the control circuit and the drive circuit, and FIG. 17 is an explanatory diagram showing an operation example of the power conversion device using the circuit of FIG. In FIG. 16, the same or equivalent components as those shown in FIGS. 9 and 12 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The control circuit 13 includes an operation command output circuit 28 that outputs an operation command for the power converter, an output command calculation circuit 50 that outputs an output command value, a subtractor 52 that limits the output command value, an air temperature The control circuit 53 includes an air temperature upper limit set value output circuit 54 and a switch 55 that performs a switching operation in response to a fan failure signal from the temperature monitoring circuit 20. The air temperature adjustment circuit 53 includes, for example, a comparator and a proportional integration controller, and subtracts the air temperature upper limit set value output from the air temperature upper limit set value output circuit 54 from the air temperature detected by the air temperature detection sensor 21. The amount is input to, for example, a proportional integration controller, and the deviation between the detected air temperature and the air temperature upper limit set value is output.

  The switch 55 is tilted to the position shown in FIG. 16 when the fan failure signal is not output from the temperature monitoring circuit 20, and operates to be tilted toward the air temperature adjustment circuit 53 when the fan failure signal is output. .

  According to this control circuit 13, in a normal state where the temperature monitoring circuit 20 has not detected a fan failure, the switch 55 is in the position shown in the figure, and a zero limit value is added to the subtractor 52. As a result, no limitation is imposed on the output command value from the output command calculation circuit 50, and it is directly input to the PWM modulation circuit 51, and the power converter is operated with an output corresponding to the output command value. At this time, the fan 18 is operated, the power converter is maintained at a predetermined output value, and the air temperature inside the power converter is kept below a predetermined temperature.

  Here, if the operation of the fan 18 is stopped, as shown in FIG. 17, the air temperature in the power conversion device increases rapidly, and the temperature monitoring circuit 20 outputs a fan failure signal. In response to this, the switch 55 of the control circuit 13 is tilted toward the air temperature adjustment circuit 53, and the output of the air temperature adjustment circuit 53 is input to the subtractor 52. At this time, the operation command from the operation command output circuit 28 is continued as it is.

  The subtractor 52 subtracts the output of the air temperature adjustment circuit 53 from the output command value output from the output command calculation circuit 50 and performs calculation to obtain the output command value to the PWM modulation circuit 51. The PWM modulation circuit 51 performs pulse width modulation with this output command value, so that the power converter reduces its output and the air temperature upper limit setting in which the air temperature is set by the air temperature upper limit set value output circuit 54. Drive to a value. As a result, even if the fan 18 is stopped, the power conversion device continues to operate in a state where the output is maintained at the set air temperature upper limit value. Since the device output is reduced, the current flowing through the power device 11 and the conductor is reduced, the amount of heat released to the inside of the device is reduced, and the increase in the air temperature in the power conversion device is suppressed. The air temperature in the power conversion device is a temperature corresponding to the output of the device.

DESCRIPTION OF SYMBOLS 11 Power device 12 Drive circuit 13 Control circuit 14 Cooling body 15 Case 16 Air 17 Cooling fin 18 Fan 20 Temperature monitoring circuit 21 Air temperature detection sensor 22 Air temperature detection circuit 23 Air temperature abnormality detection circuit 24 Comparator 25 Air temperature abnormality detection Value setting circuit 26 Air temperature rise rate detection circuit 27 Air temperature rise rate abnormality detection value setting circuit 28 Operation command output circuit 29 Gate circuit 30 Output command circuit 31 Limiter circuit 32 Output limit value calculation circuit 40 Radiator 41 Pump 42 Cooling body temperature Detection sensor 43 Cooling body temperature detection circuit 44 Fan failure detection circuit 45 Comparator 46 Cooling body temperature abnormality detection value setting circuit 47 Gate circuit 48 Cooling body temperature rise rate detection circuit 49 Cooling body temperature rise rate abnormality detection value setting circuit 50 Output command Arithmetic circuit 51 PWM modulation circuit 52 Subtractor 53 Air temperature control circuit 54 Air temperature upper limit set value output circuit 55 Switch

Claims (15)

A closed-type cooling device that cools a power device in a housing with a cooling body, and a fan circulates air in the housing to cooling fins that are thermally connected to the cooling body to cool the air in the housing. In the power converter,
A temperature monitoring unit for detecting an abnormality in the air temperature inside the housing;
A control unit for limiting the device output in response to the detection of an abnormality in the air temperature by the temperature monitoring unit;
A power conversion device comprising:   The power converter according to claim 1, wherein the temperature monitoring unit determines that the air temperature is abnormal by detecting that the air temperature inside the housing has increased to a predetermined value or more.   The power converter according to claim 1, wherein the temperature monitoring unit detects that the air temperature in the housing has increased at a rate of increase of a predetermined value or more and determines that the air temperature is abnormal.   4. The power conversion device according to claim 1, wherein the control unit stops the output of the device when the temperature monitoring unit detects an air temperature abnormality. 5.   4. The control unit according to claim 1, wherein when the temperature monitoring unit detects an air temperature abnormality, the control unit reduces the device output and continues the operation. 5. Power conversion device.   When the temperature monitoring unit detects an air temperature abnormality, the control unit dynamically controls the device output so that the air temperature inside the housing does not exceed a predetermined value, and continues the operation. The power conversion device according to claim 1, wherein the power conversion device is a power conversion device.   The temperature monitoring unit further has a function of detecting a temperature abnormality of the cooling body, and detects that the air temperature inside the housing has risen to a predetermined value or more only when the temperature of the cooling body is normal. The power converter according to claim 1, wherein the controller determines that the fan is out of order, and the control unit limits the device output.   The temperature monitoring unit further has a function of detecting a temperature rise rate abnormality of the cooling body, and the rate of increase of the air temperature inside the housing is equal to or higher than a predetermined value only when the temperature rise rate of the cooling body is normal The power converter according to claim 1, wherein the controller determines that the fan has failed and detects that the fan has failed, and the control unit limits the device output.   The power converter according to claim 7 or 8, wherein the controller stops the output of the device when the temperature monitoring unit detects a failure of the fan.   9. The power conversion device according to claim 7, wherein when the temperature monitoring unit detects a failure of the fan, the control unit reduces the output of the device and continues the operation. .   When the temperature monitoring unit detects a failure of the fan, the control unit dynamically controls the device output so that the air temperature inside the housing does not exceed a predetermined value so as to continue the operation. The power converter according to claim 7 or 8, wherein A closed type power conversion system that cools a power device inside a housing with a cooling body, and circulates air inside the housing to cooling fins that are thermally connected to the cooling body to cool the air inside the housing. In the fan failure detection method for circulating air through the cooling fin to the cooling fin in the apparatus,
Detecting the air temperature inside the housing,
A fan failure detection method for a power converter, wherein the fan failure is detected by detecting that the air temperature has risen above a predetermined value. A closed type power conversion system that cools a power device inside a housing with a cooling body, and circulates air inside the housing to cooling fins that are thermally connected to the cooling body to cool the air inside the housing. In the fan failure detection method for circulating air through the cooling fin to the cooling fin in the apparatus,
Detecting the air temperature inside the housing and the temperature of the cooling body,
A fan failure detection method for a power converter, wherein when the temperature of the cooling body is normal, it is detected that the air temperature has risen to a predetermined value or more, and the failure of the fan is detected. . A closed type power conversion system that cools a power device inside a housing with a cooling body, and circulates air inside the housing to cooling fins that are thermally connected to the cooling body to cool the air inside the housing. In the fan failure detection method for circulating air through the cooling fin to the cooling fin in the apparatus,
Detecting the rate of increase in air temperature inside the housing,
A fan failure detection method for a power converter, wherein the fan failure is detected by detecting that the rate of increase in air temperature has risen to a predetermined value or more. A closed type power conversion system that cools a power device inside a housing with a cooling body, and circulates air inside the housing to cooling fins that are thermally connected to the cooling body to cool the air inside the housing. In the fan failure detection method for circulating air through the cooling fin to the cooling fin in the apparatus,
Detecting the rate of increase in the air temperature inside the housing and the rate of increase in the temperature of the cooling body;
The power conversion characterized in that when the rate of increase in temperature of the cooling body is normal, it is detected that the rate of increase in air temperature has risen to a predetermined value or more and a failure of the fan is detected. Device fan failure detection method.

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