JP2011083152A - Power converter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the following problems of a power converter: when installed in a self-support board, a temperature detector of a main element in the power converter detects heat to stop the power converter due to overheat protection, when heat accumulates in the self-support board to raise the temperature therein due to the loss generated by the power converter, unless cooled by a cooling fan that has a proper amount of wind. <P>SOLUTION: The power converter determines the cause of overheating based on a value of temperature in the power converter which is set in advance; a temperature detected by a temperature detector provided on a cooling fin; a temperature detected by a temperature detector provided in the power converter case; and a value detected by a current detector. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a power conversion device.

  Since the power semiconductor in the power conversion device generates a large loss, heat generated by this loss is conducted to the cooling fin and the cooling fin is cooled by the cooling fan.

  Here, in order to extend the life of the cooling fan, which is a lifespan component, the temperature on the cooling fin on which the power semiconductor is mounted is detected, and the on / off control of the cooling fan is performed based on the level of this temperature detection value. Is disclosed (see Patent Document 1).

  Patent Document 2 discloses a self-supporting panel ventilation device that facilitates ventilation and maintenance management in a self-supporting panel with a built-in electric device. As described in paragraph [0006] of Patent Document 2, the bottom plate opening of the freestanding board communicates with the floor opening communicating with the ventilation path below the floor, and the inside of the panel is panelized because air is sucked from the lower surface of the board. Even if it is done, it can be effectively distributed to each part of the panel, and sufficient ventilation can be provided to prevent high temperatures. In addition, since the filter can be inserted and removed freely from the entire surface of the free standing board between the bottom plate opening and the floor opening, it is very easy to attach and remove the filter and the maintenance of the filter is easy. The structure is described.

Japanese Laid-Open Patent Publication No.7-154976 Japanese Unexamined Patent Publication No. 7-31014

  However, in Patent Document 1, the temperature detection value is set at one point, and the temperature detection value cannot be arbitrarily set. Further, there is no disclosure of an abnormality processing method for determining the cause of temperature overheating of the power converter. Patent Document 2 does not disclose an abnormality processing method for determining the cause of temperature overheating of the power converter.

  Since the power semiconductor in the power converter generates a large loss, heat generated by this loss is conducted to the cooling fin, and if the cooling fin is not cooled by the cooling fan, it is not possible to protect the power semiconductor from thermal destruction due to overheating. Can not.

  As the number of rotations of the cooling fan, in order to cool the main element of the inverter, an object that can be rotated at a high rotation number, that is, a high rotation number is preferable.

  However, the ambient temperature of the power conversion device is not constant yearly, the ambient temperature varies greatly even in the installation environment of the user, and varies depending on the installation environment.

  However, when the power converter is installed in a freestanding board, heat is trapped in the freestanding board unless it is cooled by a cooling fan with an appropriate air flow due to the loss generated by the power converter, especially the outside air temperature. In high summer, due to the temperature rise in the freestanding panel, the temperature detector of the main element in the power converter (inverter) often detects heating and the power converter suddenly stops overheating protection. appear.

  In such an installation environment, it is not the life of the cooling fan inside the power converter that cools the main element, but in an installation environment that contains a lot of dust, cotton dust, etc., the intake air that sucks outside air into the panel The dust, cotton dust, etc. are clogged in the air port, so that sufficient discharge cannot be performed. As the temperature in the freestanding panel rises, the ambient temperature of the power converter installed in the freestanding board also rises and the temperature detector becomes It detects the overheating.

  In this case, there is a problem that the facility is stopped and it takes time until the cause is identified in order to identify and eliminate the cause without determining the cause.

  For this reason, since it was impossible to perform preventive maintenance completely on the equipment, the maintenance time was the equipment stop in the event of an emergency, and naturally it was a factor that caused a significant obstacle to productivity.

  In order to solve the above problems, for example, a forward converter made of a power semiconductor that rectifies an alternating voltage of an alternating current power source and converts it into a direct current voltage, and a direct current intermediate circuit having a smoothing capacitor that smoothes the direct current voltage of the forward converter, An inverter comprising a power semiconductor for converting a DC voltage of the forward converter into an AC voltage, a current detecting means for detecting a current, a cooling fin on which the power semiconductor is mounted, and provided on the cooling fin. In a power converter that outputs a variable voltage variable frequency AC power and controls the speed of the AC motor in advance, comprising a temperature detector and a digital operation panel that can set, change, abnormal state and monitor display of various control data, The set temperature set value inside the power converter, the detection temperature 1 of the temperature detector provided on the cooling fin, and the power converter provided inside the casing A configuration is adopted in which the cause of temperature overheating of the power converter is determined from the detected temperature 2 of the temperature detector and the detected value of the current detector.

  From the detection temperature 1 of the temperature detector provided on the cooling fin equipped with the power semiconductor in the power converter, the detection temperature 2 of the temperature detector provided in the power converter housing, and the detection value of the current detector , Because the cause of abnormal overheating can be accurately monitored from the digital operation panel connected to the control circuit equipped with a microcomputer that controls the entire power converter, an alarm warning of abnormal temperature is output due to abnormal overheating By being configured to be able to do so, it is possible to easily determine what will be restored if measures are taken or replaced.

  For this reason, there is an effect that maintenance time can be shortened and facility downtime can be greatly shortened.

  According to the present invention, when the temperature detected by the temperature detector provided in the power converter reaches the set input temperature without installing a special temperature detector in the freestanding board in which the power converter is stored. The temperature abnormal alarm is displayed on the digital operation panel and the alarm warning signal Sig1 for temperature abnormality can be output from the control terminal block. The operator can operate the alarm warning signal Sig1 for temperature abnormality from the control terminal block. Because the warning signal displayed on the remote control panel allows the operator to check that the internal temperature in the freestanding panel has become abnormally high without installing a special temperature detector in the freestanding panel. Therefore, it can be used for a power conversion device that can reduce maintenance time and greatly reduce facility downtime.

It is a main circuit block diagram of a power converter device. It is an example of the main circuit component arrangement | positioning figure of a power converter device. It is one Example of the temperature abnormality detection using a thermistor. It is another Example of the temperature abnormality detection using a thermistor. It is one Example of the flowchart figure in abnormality factor discrimination | determination. It is another Example of the flowchart figure in abnormality factor discrimination | determination. It is one Example which accommodated the power converter device in the self-supporting board with an external air fan. It is another Example which accommodated the power converter device in the self-supporting board without an external air fan.

  In the following, embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the illustrated example.

  FIG. 1 shows a main circuit configuration diagram of a power converter 21 according to the present invention. 1 is a forward converter that converts AC power into DC power, 2 is a smoothing capacitor, 3 is an inverse converter that converts DC power into AC power of an arbitrary frequency, and 4 is an AC motor. Reference numeral 6 denotes a cooling fan for cooling the power module 11 in the forward converter and the reverse converter. 8 is a digital operation panel that can set, change, abnormal state and monitor display of various control data of the power converter.

  A temperature detector 7 is mounted on the cooling fin and detects heating of the power module in the forward converter and the reverse converter. The temperature detector 7 is a thermistor whose resistance value changes with temperature. This thermistor can be either a material whose resistance value increases as the temperature rises or a material whose resistance value decreases as the temperature rises.

  Reference numeral 9 denotes a temperature detector provided in the power semiconductor module 11. A control circuit 5 controls the switching elements of the inverter and controls the entire power converter 21. The control circuit 5 is equipped with a microcomputer. Various control data input from the digital operation panel 8 are provided. It is configured so that necessary control processing can be performed according to the situation.

  Reference numeral 10 denotes a drive circuit for driving a switching element of the inverse converter. Reference numeral 17 denotes a temperature detector that detects the temperature inside the power converter, and is provided on the substrate of the drive circuit. In the present embodiment, 17 is provided on the substrate of the drive circuit, but the purpose is to detect the temperature inside the power converter, and therefore, the present invention is not limited to the substrate. 18 is a current detector. Since the inverter which is a power converter is a well-known technique, detailed description is omitted.

  FIG. 2 is an example of a main circuit component layout diagram. A main circuit board 12 includes a smoothing capacitor 2, a switching regulator power supply circuit, a drive circuit 10, and the like. Further, the main circuit board 12 is provided with a control terminal block 16 for connection with an external terminal. A cooling fan for cooling the cooling fin 14 by mounting the power semiconductor 13 composed of a composite module in which the forward converter 1, the reverse converter 3 and the temperature detector 9 are mounted in one module. 6 (dotted line portion in the figure) is a structure attached to the upper surface of the cooling fin 14. The power semiconductor 13 and the main circuit board 12 mounted on the cooling fin 14 are accommodated in a resin mold case 15. The resin mold case 15 includes a control circuit 5 and a digital operation panel 8. It has been.

  Of course, even if the temperature detector 7 mounted on the cooling fin 14 is provided on the cooling fin 14 in the vicinity of the power semiconductor 13, there is no problem as intended by the present invention. Since the power semiconductor 13 that is a composite module generates a large loss, heat generated by the loss is conducted to the cooling fin 14 and the cooling fan 6 cools the cooling fin 14. With this cooling fan 6, the power semiconductor 13 which is a composite module can be protected from overheating due to temperature rise.

  Here, when the ambient temperature of the power converter 21 housed in the self-supporting panel is abnormally high, the power converter 21 may stop due to overheat protection even if the power converter 21 is operating below its rated current. Since the power semiconductor 13 in the power converter 21 generates a large loss, the heat stagnates in the freestanding board unless heat generated by the loss is discharged from the freestanding board to the outside air. The overheat protection by the heater is activated and the power converter is stopped.

  In order to protect the power semiconductor from thermal destruction due to overheating, when the temperature T1 of the temperature detector 7 reaches a temperature Tlim that should never be exceeded, it is necessary to protect the power converter over temperature. In this case, when the ambient temperature of the power converter is Ta, between the detected temperature rise value ΔT1 of the temperature detector 7 provided on the cooling fin 14 in the vicinity of the power semiconductor 13 and the temperature Tlim, The relational expression Tlim <(ΔT1 + Ta) = T1 is established.

  Here, the detected temperature rise value ΔT1 of the temperature detector 7 is naturally proportional to the amount of heat generated by the power semiconductor, and the amount of generated heat is proportional to the current of the power converter.

  Furthermore, if the detected temperature rise value ΔT1 of the temperature detector 7 is within the low rated current of the power converter, it is the sum (ΔT1 + Tam) even at the maximum ambient temperature Tam of the power converter. The heat is designed not to exceed the Tlim.

  However, even if it is within the lower rated current of the power converter, if the ambient temperature Ta of the power converter exceeds the maximum specified ambient temperature Tam, (ΔT1 + Ta) becomes larger than the Tlim. . In this case, the overheat protection by the temperature detector 7 operates and the power converter suddenly stops although the power converter is used within the low rated current.

  In other words, if the ambient temperature of the power converter housed in the freestanding board is abnormally high (the temperature in the freestanding board), the user determines that it is okay because the power converter is used within the rated current. In spite of this, the power conversion device suddenly stops due to overheat protection. In this sense, the ambient temperature of the power converter is an extremely important factor for overheating protection of the power semiconductor. Factors that cause the ambient temperature of the power converter to exceed the specified maximum ambient temperature Tam are a decrease in the rotational speed due to the life of the outside air fan, and dust and cotton dust clogged in the intake air inlet that sucks in outside air into the panel It is conceivable that the discharge capacity is lowered and heat is trapped in the freestanding board, and the ambient temperature is abnormally increased.

  The more important the power conversion device is as a part of the production line, the more sudden the unexpected stoppage is, the more serious the problem is until the cause can be identified. In this sense, in the event of an emergency, shortening the maintenance time and shortening the downtime are extremely important in terms of maintenance, and appropriate preventive maintenance is required.

  FIG. 3 shows an embodiment relating to a temperature abnormality detection method using a thermistor made in view of the above problem.

The temperature detector 7 is a thermistor. The temperature characteristics of the thermistor in this case are those whose resistance value decreases as the temperature rises, and the resistance value RT of the thermistor at the temperature T is an example in the case of using the thing represented by the following formula.
(Equation 1)
RT = R25 * exp [B * {1 / (T + 273) -1 / (T25 + 273)}]
here,
R25: Thermistor resistance at 25 ° C
T25: Temperature 25 ° C (T25 = 25)
B: Constant When the temperature of the thermistor rises, the resistance value RT of the thermistor decreases, and the input voltage at the analog port terminal A / D1 of the MCU increases due to the voltage dividing resistor R2 mounted in the control circuit 5.
In accordance with this voltage value, the MCU calculates the temperature T1 in real time from the above (Equation 1).

  Since (Equation 1) is complicated to calculate, data indicating the correlation between the input voltage of the analog port terminal A / D1 proportional to the resistance value of the thermistor and the temperature of the thermistor is obtained from the equation (Equation 1). The table data may be stored in advance in a non-volatile memory, and the temperature T1 of the thermistor may be called in real time from this table data.

The temperature detector 17 that detects the temperature inside the power converter 21 is also a thermistor. The temperature characteristics are the same as in (Formula 1). When the temperature of the thermistor rises, the resistance value RT of the thermistor decreases, and the voltage divider resistor R1 mounted in the control circuit 5 causes the analog port terminal A / D2 of the MCU. The input voltage increases.
In accordance with this voltage value, the MCU calculates the temperature T2 from the (Equation 1) in real time. Since the calculation of (Equation 1) is complicated, data indicating the correlation between the input voltage of the analog port terminal A / D2 proportional to the resistance value of the thermistor and the temperature of the thermistor is obtained from (Equation 1), and this is calculated in advance. The table data may be stored in a non-volatile memory and the thermistor temperature T2 may be called from the table data in real time.

  Further, the current of the AC motor is detected by the current detector 18, and this detected value is transmitted to the analog port terminal A / D3 of the MCU through the amplifier 19 mounted in the control circuit 5.

  From the input voltage value of the analog port terminal A / D3, it is determined whether the MCU is in the load state of the AC motor, that is, whether it is a heavy load (more than the rated current) or a light load (below the rated current).

  Based on the input voltage value of the analog port terminal A / D2 connected to the output of the temperature detector 17 for detecting the temperature inside the power converter, the temperature T2 calculated by the MCU from the above (Equation 1) is preset. When the temperature input value T0 inside the power converter is reached, the MCU detects the MCU by the input voltage value of the analog port terminal A / D1 connected to the output of the temperature detector 7 that detects the heating of the power module. From the temperature T1 calculated from (Equation 1) and the input voltage value of the analog port terminal A / D3 connected to the output of the current detector 18, the following causes of abnormal overheating are classified.

  Based on the input voltage value of the analog port terminal A / D1 connected to the output of the temperature detector 7 for detecting the heating of the power module, the temperature T1 calculated by the MCU from the above (Equation 1) is the non-heating state of the power module. And when the MCU determines that the load state of the AC motor is a light load (less than the rated current) based on the input voltage value of the analog port terminal A / D3, the ambient temperature of the power converter Abnormality is displayed on the digital operation panel 8.

  Even if the preset temperature input value T0 in the power converter 21 is set from the digital operation panel 8, the intent of the present invention is exactly the same.

  In this case, the overheat abnormality display content is naturally displayed on the digital operation panel 8, but the power conversion device is not stopped and the operation is continued.

  The operator can immediately determine the temperature state of the power converter 21 by visually checking the overheat abnormality display content displayed on the digital operation panel 8, and can take appropriate measures.

  Of course, since the power semiconductor in the power converter 21 generates a large loss, heat generated by this loss is conducted to the cooling fin, and the power semiconductor is protected from thermal destruction due to overheating unless the cooling fin is cooled by the cooling fan. Therefore, when the calculated temperature T of the thermistor reaches a temperature Tlim that should never be exceeded, it is necessary to stop the power converter from overtemperature protection.

  Even if the output from the temperature detector 9 provided in the power semiconductor module is used as an alternative to the temperature detector 7 mounted on the cooling fin 14, the intended point of the present invention is not changed. Even if the temperature characteristic of the thermistor is such that its resistance value RT increases as the temperature rises, there is no problem as intended by the present invention.

  FIG. 4 shows another embodiment relating to a temperature abnormality detection method using a thermistor. As in FIG. 3, it is possible to immediately determine the temperature condition of the power converter by observing the overheat abnormality display content displayed on the digital operation panel 8, and to take appropriate measures. It is.

  Since it is not realistic to always observe the overheat abnormality display content displayed on the digital operation panel 8, the overheat abnormality display content is displayed on the digital operation panel 8, and the alarm warning signal Sig1 for temperature abnormality is a control terminal. This is another embodiment configured to be able to output from the table 16.

  When the temperature abnormality alarm warning signal Sig1 is output from the control terminal block 16, the power converter is not stopped and the operation is continued. In other words, this state is not the temperature level at which the power semiconductor will cause thermal destruction due to overheating, but warns the operator that it is dangerous if the overheating state continues, and promptly take appropriate measures. This is for the purpose of arousing the power conversion device without stopping the overheat protection.

  Of course, since the power semiconductor in the power converter 21 generates a large loss, heat generated by this loss is conducted to the cooling fin 14, and unless the cooling fin 14 is cooled by the cooling fan 6, the power semiconductor is heated by overheating. Since it cannot be protected from destruction, when the calculated temperature T of the thermistor reaches a temperature Tlim that must never be exceeded, it is necessary to stop the power conversion device from overtemperature protection.

In this embodiment, the operator can monitor the alarm warning signal Sig1 of the temperature abnormality from the control terminal block 16 on the remote operation panel side, so there is no need to constantly monitor the digital operation panel 8.
The operator can take appropriate measures based on the warning signal displayed on the remote control panel.

  Similarly to the above, even if the output from the temperature detector 9 provided in the power semiconductor module is used as an alternative to the temperature detector 7 mounted on the cooling fin 14, the intended point of the present invention is not changed. . Even if the temperature characteristic of the thermistor is such that its resistance value RT increases as the temperature rises, there is no problem as intended by the present invention.

  FIG. 5 is an example of a flowchart in the abnormality factor determination. The present embodiment is an example in which the cooling fan 6 is not attached to the power conversion device disclosed in FIG.

  First, when an abnormality occurs, it is determined whether or not the temperature sensor 7 is overheated. If it is not overheated, the output of the power converter is shut off, and the abnormality (for example, overcurrent display) is displayed on the digital operation panel. Display in 8.

  The state where there is no abnormal heating means that the MCU is in accordance with the input voltage value of the analog port terminal A / D1 of the MCU by the voltage dividing resistor R2 mounted on the control circuit 5 from the temperature detector 7 disclosed in FIG. The temperature T1 is calculated from 1), and the calculated temperature T1 is compared with the temperature Tlim that should never be exceeded, and T1 <Tlim.

  The overheat abnormality state means that the MCU is in accordance with the input voltage value of the analog port terminal A / D1 of the MCU by the voltage dividing resistor R2 mounted on the control circuit 5 from the temperature detector 7 disclosed in FIG. ), The temperature T1 is calculated, and the calculated temperature T1 is compared with the temperature Tlim that should never be exceeded, and T1 ≧ Tlim.

  In this state (T1 ≧ Tlim), the MCU is controlled by the voltage divider resistor R1 mounted on the control circuit 5 from the temperature detector 17 disclosed in FIG. 3 according to the input voltage value of the analog port terminal A / D2 of the MCU. The temperature T2 is calculated from Equation 1) and compared with the preset temperature input value T0 inside the power converter. If T2 <T0, the output of the power converter is shut off and the abnormality is displayed as an overheat abnormality 1 For example, OH-PM (overheating factor: meaning overheating of power module due to overload) is displayed on the digital operation panel 8.

  Here, if T2 ≧ T0, the MCU determines that the load state of the AC motor is a light load (less than the rated current) from the input voltage value of the analog port terminal A / D3 connected to the output of the current detector 18 In such a case, the output of the power conversion device is not cut off, and the abnormality is overheated abnormally displayed 2, and OH-AMB (overheating factor: meaning that the ambient temperature is high) is displayed on the digital operation panel 8.

  Further, when the MCU determines that the load state of the AC motor is a heavy load (more than the rated current), the output of the power converter is shut off, and the abnormality is indicated as an overheat abnormality display 1, and the OH-PM is digitally operated. Display on panel 8.

  Even if the operator arbitrarily inputs a preset temperature input value T0 in the power conversion device from the digital operation panel 8 in advance, the intention of the present invention does not change.

  Further, the embodiment of FIG. 4 is configured so that the alarm warning signal Sig1 of temperature abnormality can be output from the control terminal block 16 only when the overheat abnormality display 2 of the OH-AMB is displayed on the digital operation panel 8. It is what.

  Of course, since the power semiconductor in the power converter 21 generates a large loss, heat generated by this loss is conducted to the cooling fin 14, and unless the cooling fin 14 is cooled by the cooling fan 6, the power semiconductor is heated by overheating. Since it cannot be protected from destruction, when the calculated temperature T of the thermistor reaches a temperature Tlim that must never be exceeded, it is necessary to stop the power conversion device from overtemperature protection.

  FIG. 6 is another example of a flowchart in abnormality factor determination.

  In this embodiment, the cooling fan 6 is mounted on the power conversion device disclosed in FIG. A detection circuit for detecting the number of revolutions is provided in the cooling fan, and the abnormality in the number of revolutions of the cooling fan 6 is determined in advance as, for example, 30% lower than the initial number of revolutions.

  When an abnormality has occurred, it is determined whether or not an overheating abnormality has occurred from the temperature sensor 7, and if not an overheating abnormality, the output of the power converter is shut off and an abnormality display related to the abnormality (for example, an overcurrent display or a cooling fan) (Abnormality display etc.) is displayed on the digital operation panel 8.

  Similar to the flowchart in FIG. 5, the state where there is no abnormal heating is the analog port terminal A / D1 of the MCU by the voltage dividing resistor R2 mounted on the control circuit 5 from the temperature detector 7 disclosed in FIG. This is the case where the MCU calculates the temperature T1 from the above (Equation 1) according to the input voltage value of the following, and compares the calculated temperature T1 with the temperature Tlim that should never be exceeded, and T1 <Tlim.

  The overheat abnormality state means that the MCU is in accordance with the input voltage value of the analog port terminal A / D1 of the MCU by the voltage dividing resistor R2 mounted on the control circuit 5 from the temperature detector 7 disclosed in FIG. ), The temperature T1 is calculated, and the calculated temperature T1 is compared with the temperature Tlim that should never be exceeded, and T1 ≧ Tlim.

  If overheating is abnormal, it is next determined whether or not the cooling fan is abnormal. At this time, if an abnormality of the cooling fan 6 has occurred, the output of the power conversion device is not cut off, and the power semiconductor temperature overheat display 3 related to the abnormality accompanying the decrease in the rotation speed of the cooling fan, for example, OH-Fan Display (overheating factor: meaning that cooling fan 6 is abnormal) is displayed on digital operation panel 8.

  If there is no abnormality in the cooling fan 6, as in FIG. 5, in this state, the temperature sensor 17 disclosed in FIG. According to the input voltage value of the port terminal A / D2, the MCU calculates the temperature T2 from the above (Equation 1) and compares it with the preset temperature input value T0 in the power converter 21, and if T2 <T0, The output of the power converter 21 is shut off, and the abnormality is displayed as an overheat abnormality display 1 and OH-PM is displayed on the digital operation panel 8.

  Here, when T2 ≧ T0, the MCU determines that the load state of the AC motor 4 is light load (less than the rated current) from the input voltage value of the analog port terminal A / D3 connected to the output of the current detector 18. If it is determined, the output of the power conversion device 21 is not shut off, and the abnormality is indicated as an overheat abnormality display 2 and OH-AMB is displayed on the digital operation panel 8. Further, when the MCU determines that the load state of the AC motor 4 is a heavy load (more than the rated current), the output of the power conversion device 21 is shut off, and the abnormality is indicated as an overheat abnormality display 1 to indicate OH-PM. Display on the digital operation panel 8.

  Even if the operator arbitrarily inputs a preset temperature input value T0 in the power converter 21 from the digital operation panel 8 in advance, the intention of the present invention does not change.

  FIG. 7 shows an embodiment in which the power converter is housed in the freestanding board 22.

  In the present embodiment, an outside air fan 20 is mounted on a self-supporting board 22 in which a power conversion device is housed, and outside air is sucked into the board through an intake air port 23 thereof.

  In this state, four power converters 21 are installed in the upper panel and four in the lower panel. Since the power semiconductor in the power converter 21 generates a large loss, if the heat generated by this loss is not exhausted from the free standing board 22 by the outside air fan 20, heat is trapped in the free standing board 22 and the outside air temperature such as in summer is high. When the temperature is high, the overheat protection by the power semiconductor temperature detector is activated, and the power converter 21 is suddenly stopped. As a workaround, an outside air fan 20 is mounted. However, since the fan is a rotating body, bearings and grease are used and it has a limited life. Of course, if the ambient temperature is high, the life of the fan is shortened, and the definition of the life generally refers to a point in time when the rotational speed is reduced by, for example, 30% with respect to the initial rotational speed.

  For this reason, the rotation speed of the outside air fan 20 decreases with the operating time. Since the decrease in the rotational speed is directly proportional to the discharge capacity, the heat generated by the loss cannot be sufficiently discharged from the free standing board 22 to the outside air, so that heat is trapped in the free standing board 22 and overheating protection is performed by the power semiconductor temperature detector. It occurs that the power conversion device suddenly stops operating. However, the installation environment of the power converter varies greatly depending on the type of industry, and it is difficult to adjust it to ideal conditions, and it is difficult to accurately predict when the discharge capacity declines due to the life of the outside air fan 20. is there.

  That is, it is necessary to prevent and maintain a sudden stop of the power conversion device due to the life of the outside air fan, and this preventive maintenance is strongly required depending on the importance of the equipment.

  In addition, although it is not the life of the outside air fan, in an installation environment that contains a lot of dust and cotton dust, the dust and cotton dust etc. are clogged in the intake air port 23 with an air filter that sucks outside air into the panel. However, sufficient discharge cannot be performed, heat is trapped in the freestanding board 22, the overheat protection by the power semiconductor temperature detector is activated, and the power converter is suddenly stopped.

  Therefore, by storing the power conversion device 21 that can execute the flowchart in the abnormality factor determination shown in FIG. 6, the operator can detect the temperature abnormality without installing a special temperature detector in the self-supporting panel 22. The alarm warning signal Sig1 can be monitored from the control terminal block 16 on the remote control panel side, and the internal temperature in the self-supporting panel 22 is abnormal due to the warning signal displayed on the remote control panel (the power converter is in an output non-blocking state). The temperature detector of the main element in the power converter (inverter) 21 detects the heating due to the fact that the heat has stagnated in the freestanding board 22, and the power converter Can be prevented from suddenly shutting down due to overheat protection, preventive maintenance is possible, and equipment downtime can be significantly reduced. Further, OH-AMB (cause of overheating: meaning that the ambient temperature is high) can be confirmed on the digital operation panel 8 as the overheat abnormality display 2.

  FIG. 8 shows another embodiment in which the power converter is housed in the freestanding board 22. The difference from FIG. 7 is the case where the outside air fan 20 is not attached to the self-supporting panel 22 in which the power converter is housed. In this case, heat generated by the loss accumulates in the freestanding board 22, and when the outside air temperature is high such as in summer, the overheat protection by the temperature detector of the power semiconductor operates, and the power conversion device suddenly stops.

  Of course, this is not the life of the outside air fan, but in an installation environment that contains a lot of dust and cotton dust, the dust and cotton dust are clogged in the intake air port 23 with an air filter that sucks in the outside air into the panel. However, sufficient discharge cannot be performed, heat is trapped in the freestanding board 22, the overheat protection by the power semiconductor temperature detector is activated, and the power converter is suddenly stopped.

  Therefore, by storing the power conversion device 21 that can execute the flowchart in the abnormality factor determination shown in FIG. 5, without installing a special temperature detector for monitoring the temperature in the panel in the self-supporting panel 22, The operator can monitor the alarm warning signal Sig1 for the temperature abnormality from the control terminal block 16 on the remote operation panel side, and the warning signal displayed on the remote operation panel (the power conversion device is in the output non-cutoff state) It is possible to know that the internal temperature in the freestanding board 22 has become abnormally high without installing a special temperature detector in the 22, and the power conversion is due to the factor that the heat has stagnated in the freestanding board 22. Since the temperature detector of the main element in the device (inverter) detects heating and prevents the power converter from suddenly stopping overheating, preventive maintenance is possible, greatly reducing facility downtime it can

  Further, OH-AMB (cause of overheating: meaning that the ambient temperature is high) can be confirmed on the digital operation panel 8 as the overheat abnormality display 2.

  According to the present invention, the operator can monitor the alarm warning signal Sig1 of the temperature abnormality from the control terminal block 16 on the remote operation panel side without installing a special temperature detector in the self-supporting panel 22, and can be operated remotely. The warning signal displayed on the panel can tell that the internal temperature in the self-supporting panel 22 has become abnormally high. Because the temperature detector of the main element of this product detects heating and prevents the power converter from suddenly stopping overheating, the maintenance time can be shortened, and the equipment downtime can be greatly reduced. There is an effect to say.

DESCRIPTION OF SYMBOLS 1 ... Forward converter, 2 ... Smoothing capacitor, 3 ... Reverse converter, 4 ... AC motor, 5 ... Control circuit, 6 ... Cooling fan, 7 ... Temperature detector, 8 ... Digital operation panel, 9 ... Power semiconductor Temperature detector mounted inside, 10 ... drive circuit, 11 ... power semiconductor module, 12 ... main circuit board, 13 ... composite module in which forward converter, reverse converter and temperature detector are mounted in one module DESCRIPTION OF SYMBOLS 14 ... Cooling fin, 15 ... Resin mold case, 16 ... Control terminal block, 17 ... Temperature detector provided in the inside of a power converter case, 18 ... Current detector, 19 ... Amplifier, 20 ... Outside air fan, 21 ... Power converter, 22 ... Stand-alone board, 23 ... Air inlet with air filter, MCU ... Microprocessor, PM ... Power semiconductor module, A / D ... Analog port of MCU, PHC ... Photo camera R, RT ... resistance value at the temperature T of the thermistor, R1 ... resistance, R2 ... resistance, 5V ... DC voltage, T ... temperature of the thermistor (detection temperature, calculation temperature), Tlim ... to protect the power semiconductor from thermal destruction Thermistor temperature, ΔT1, the detected temperature rise value of the temperature detector 7, Tam, power converter specification maximum ambient temperature

Claims (6)

A forward converter made of a power semiconductor that rectifies the AC voltage of the AC power source and converts it into a DC voltage;
A DC intermediate circuit having a smoothing capacitor for smoothing the DC voltage of the forward converter;
An inverse converter made of a power semiconductor that converts the DC voltage of the forward converter into an AC voltage;
Current detection means for detecting current;
A cooling fin on which the power semiconductor is mounted;
A temperature detector provided on the cooling fin;
Digital operation panel that can set, change, abnormal status and monitor display of various control data,
In a power conversion device that outputs AC power of variable voltage variable frequency and that controls the speed of an AC motor,
The preset temperature setting value inside the power converter, the detection temperature 1 of the temperature detector provided on the cooling fin, the detection temperature 2 of the temperature detector provided in the power converter housing, and the current detection A power conversion device, wherein a factor of temperature overheating of the power conversion device is determined based on a detection value of the converter. A forward converter made of a power semiconductor that rectifies the AC voltage of the AC power source and converts it into a DC voltage;
A DC intermediate circuit having a smoothing capacitor for smoothing the DC voltage of the forward converter;
An inverse converter made of a power semiconductor that converts the DC voltage of the forward converter into an AC voltage;
Current detection means for detecting current;
A cooling fin on which the power semiconductor is mounted;
A temperature detector provided inside the power semiconductor;
A cooling fan for cooling the power semiconductor mounted on the cooling fin;
Digital operation panel that can set, change, abnormal status and monitor display of various control data,
In a power conversion device that outputs AC power of variable voltage variable frequency and that controls the speed of an AC motor,
The preset temperature setting value inside the power converter, the detection temperature 1 of the temperature detector provided on the cooling fin, the detection temperature 2 of the temperature detector provided in the power converter housing, and the current detection A power conversion device, wherein a factor of temperature overheating of the power conversion device is determined based on a detected value of the converter.   The power converter according to claim 1 or 2, wherein a temperature set value of a detected temperature 2 of a temperature detector provided inside the power converter can be arbitrarily input and set from the digital operation panel.   The power conversion device according to any one of claims 1 to 3, wherein a detection temperature of a temperature detector provided in the power semiconductor is used as the detection temperature 1 of the temperature detector.   5. The power conversion device according to claim 1, wherein the temperature detector includes a thermistor that exhibits a resistance value proportional to a temperature. 6.   The alarm signal is output without shutting off the output of the power converter when it is determined that the temperature overheating factor of the power converter is an ambient temperature abnormality of the power converter. Item 6. The power conversion device according to any one of Items 5 to 6.

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