JP2011024642A - Semiconductor power converter and x-ray high-voltage apparatus using the same, filament heater, x-ray ct scanner, and x-ray diagnostic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor power converter which continues to operate without lowering a circuit function in operation even when an abnormality occurs in coolers cooling a semiconductor power conversion circuit comprising an inverter circuit and the like and there is a fear of circuit parts being overheated and can be inexpensively embodied. <P>SOLUTION: The semiconductor power converter having the semiconductor power conversion circuit comprising a plurality of semiconductor devices, a heat dissipating structure dissipating the heat of the semiconductor power conversion circuit, the coolers cooling the heat dissipating structure, a temperature monitoring circuit having a smaller number of temperature measuring points than the number of the coolers to be installed in the vicinities of some of the semiconductor devices, and a power conversion control circuit having a plurality of temperature thresholds to stop the operation of the semiconductor power conversion circuit continues to operate by lowering the temperature thresholds by the power conversion control circuit when an abnormality occurs in the coolers. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a semiconductor power conversion device and an X-ray high voltage device using the same, and more particularly to overheating protection of a semiconductor element used in the semiconductor power conversion device.

  In an operating circuit device, if an abnormality occurs in some of the circuit components of the circuit device or a cooling fan that cools the circuit components, and the circuit components may fail due to an overheating condition, the circuit operation continues. Thus, there has been an apparatus that has improved usability to prevent a failure by reducing a load applied to a circuit component that may be overheated by the circuit apparatus.

  As a method for overheating protection of a plurality of semiconductor elements used in an inverter-type power converter, the temperature of the plurality of semiconductor elements or the vicinity thereof is detected by a plurality of temperature sensors, and the detected temperature or the highest value of the temperature rise rate is There has been a method of reducing the load applied to the power converter and continuing the circuit operation when the temperature exceeds a predetermined temperature or the rate of temperature increase (see Patent Document 1). In addition, when one of a plurality of cooling fans that cool the projection data collection unit of the X-ray CT apparatus fails, there was a method of reducing the operation clock of the projection data collection unit and continuing the operation of the X-ray CT apparatus ( (See Patent Document 2).

Japanese Unexamined Patent Publication No. 7-194094 JP 2009-56099 A

  However, in both Patent Document 1 and Patent Document 2, the function of the circuit device in operation is reduced in order to prevent the failure by reducing the load of the circuit component that may fail in an overheated state. Further, in Patent Document 1, since a temperature sensor is used for each of a plurality of semiconductor elements or in the vicinity thereof, there is a concern that the cost and circuit configuration of the temperature sensor and the temperature detection circuit are increased.

  Therefore, the object of the present invention is to continue the operation without reducing the function of the circuit in operation even when there is a possibility that the cooling device is abnormal and the circuit component is overheated, and can be implemented at a low cost. A semiconductor power conversion device, and an X-ray high voltage device, a filament heating device, an X-ray CT device, and an X-ray diagnostic device using the same are provided.

  To achieve the above object, the present invention provides a semiconductor power conversion circuit having a plurality of semiconductor elements, a heat dissipation structure that radiates heat from the semiconductor power conversion circuit, and at least two cooling devices that cool the heat dissipation structure. A cooling device monitoring circuit for monitoring an abnormality of the cooling device, a temperature monitoring circuit having a number of temperature sensors smaller than the number of cooling devices installed in the vicinity of some of the semiconductor elements, and the semiconductor power conversion A power conversion control circuit including a plurality of temperature thresholds for stopping the operation of the circuit and selecting and setting one temperature threshold from the plurality of temperature thresholds. When an abnormality of the cooling device is detected by the device monitoring circuit, the temperature threshold value selected and set by the power conversion control circuit is lowered, and the operation of the semiconductor power conversion circuit is continued. Continue.

  According to the present invention, even when an abnormality occurs in the cooling device and the semiconductor power conversion circuit may be overheated, the operation is continued without reducing the function of the semiconductor power conversion circuit in operation, and the cooling device Semiconductor power conversion device that can be implemented at low cost because the number of temperature sensors can be reduced with respect to the number, X-ray high voltage device using the semiconductor power conversion device, filament heating device, and the X-ray high voltage device, filament heating device An X-ray CT apparatus and an X-ray diagnostic apparatus can be provided.

Schematic diagram of the configuration of the semiconductor power conversion device of the present invention when there are two cooling devices Mounting layout of the semiconductor power conversion circuit, heat dissipation structure, cooling device, and temperature sensor shown in FIG. 2 is a characteristic diagram of temperature distribution on the surface of the temperature sensor unit shown in FIG. 2 and its heat dissipation structure in the left-right direction. Fig. 2 Characteristic diagram of temperature distribution on the surface of heat dissipation structure when cooling device f2 fails and stops Schematic diagram showing a configuration example of the semiconductor power conversion device of the present invention and four cooling devices Mounting layout of the semiconductor power conversion circuit, heat dissipation structure, cooling device, and temperature sensor shown in FIG. 6 is a characteristic diagram of the temperature distribution of the surface of the temperature sensor unit shown in FIG. 6 and its heat dissipation structure in the left-right direction. 6 is a characteristic diagram of the temperature distribution on the surface of the heat dissipation structure when the cooling device f6 or f3 and f6 fails and stops in FIG. Characteristic diagram of temperature distribution on the surface of heat dissipation structure when cooling device f5 or f6 shown in Fig. 6 fails and stops Schematic diagram of X-ray high-voltage device and X-ray tube using the semiconductor power conversion device of the present invention Schematic diagram of filament heating device and X-ray tube using semiconductor power conversion device of the present invention Schematic of X-ray CT apparatus using the X-ray high voltage apparatus of the present invention Flowchart diagram for explaining the sixth embodiment of the present invention Flowchart diagram for explaining the sixth embodiment of the present invention Schematic of X-ray diagnostic apparatus using the X-ray high voltage apparatus of the present invention

  Hereinafter, preferred embodiments of a semiconductor power conversion device of the present invention and an X-ray high voltage device, an X-ray CT device, and an X-ray diagnostic device using the same will be described in detail with reference to the accompanying drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiments of the invention, and the repetitive description thereof is omitted.

  An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic diagram of a configuration example of a semiconductor power conversion device according to the present invention in the case where there are two cooling devices. FIG. 2 is a mounting layout diagram of the semiconductor power conversion circuit, the heat dissipation structure, the cooling device, and the temperature sensor shown in FIG. FIG. 3 is a characteristic diagram of the temperature distribution of the temperature sensor section shown in FIG. 2 and the heat dissipating structure surface in the left-right direction. FIG. 4 is a characteristic diagram of the temperature distribution on the surface of the heat dissipation structure when the cooling device f2 fails and stops in FIG.

  As shown in FIG. 1, a semiconductor power conversion device 100 includes a semiconductor power conversion circuit 101, a heat dissipation structure 102, a cooling device monitoring circuit 103, a temperature monitoring circuit 104, a power conversion control circuit 105, a temperature sensor t1, and cooling devices f1, f2. And comprising.

  The semiconductor power conversion circuit 101 includes semiconductor elements s1 to s4. In the present embodiment, the semiconductor elements s1 to s4 are IGBTs, and the semiconductor power conversion circuit 101 is an inverter circuit composed of IGBTs. In addition, the semiconductor elements s1 to s4 may be FETs, and the semiconductor power conversion circuit 101 may be a converter circuit. The semiconductor elements s1 to s4 have the same or equivalent power consumption and heat generation amount in the semiconductor power conversion circuit 101, respectively. The heat dissipating structure 102 is disposed in close contact with the semiconductor elements s1 to s4 in order to dissipate the semiconductor elements s1 to s4. In the case of the present embodiment, the heat dissipation structure 102 is a heat sink. In addition, the heat dissipation structure 102 may be an aluminum block or the like.

  The cooling device monitoring circuit 103 is a circuit that monitors the operation of the cooling devices f1 and f2 installed in the heat dissipation structure 102 in order to dissipate heat from the heat dissipation structure 102. Is notified to the power conversion control circuit 105. In this embodiment, the cooling devices f1 and f2 are cooling fans.

  The temperature monitoring circuit 104 monitors the temperature detected by the temperature sensor t1 installed in close contact with the surface of the heat dissipation structure 102 in the vicinity of the semiconductor elements s2, s3 and notifies the power conversion control circuit 105 of the value. In this embodiment, the temperature sensor t1 is a thermistor. The temperature sensor t1 may be a thermocouple or the like. The number of temperature sensors is one or more and less than the number of cooling devices. In this embodiment, one temperature sensor is provided for two cooling devices.

  The power conversion control circuit 105 controls the semiconductor power conversion circuit 101, and information on the operating state of the cooling devices f1 and f2 sent from the cooling device monitoring circuit 103 and the temperature sent from the temperature monitoring circuit 104. Based on the temperature information of the sensor t1, the semiconductor power conversion circuit 101 is compared with a plurality of predetermined temperature thresholds that are stopped before the semiconductor power conversion circuit 101 fails due to overheating, and the semiconductor power conversion circuit 101 is stopped as necessary. The power conversion control circuit 105 changes the temperature threshold value at which the semiconductor power conversion circuit 101 is stopped depending on the operating state of the cooling device.

  The characteristic diagram of the temperature distribution shown in FIG. 3 is the horizontal axis, the cooling devices f1, f2, the semiconductor elements s1 to s4 and the temperature when viewed from the side where the cooling devices f1, f2 are installed in the mounting arrangement diagram of FIG. The positional relationship with the sensor t1 is shown, and the temperature is shown on the vertical axis. Tth1 shown on the vertical axis is a temperature threshold value when there is no abnormality in the cooling devices f1 and f2, and is a first temperature threshold value of the semiconductor power conversion device 100 shown in the present embodiment. When the temperature detected by the temperature sensor t1 becomes equal to or higher than the temperature threshold Tth1, the power conversion control circuit 105 stops the semiconductor power conversion circuit 101.

  Lt0, Lt1, and Lt2 are temperature characteristics indicating the temperature of the surface of the heat dissipation structure 102, respectively, and the surface of the heat dissipation structure 102 in the order of Lt0, Lt1, and Lt2 as the operating time of the semiconductor power conversion circuit 101 elapses. It shows how the temperature rises. tp0, tp1, and tp2 are detected temperatures obtained by detecting the surface of the heat dissipation structure 102 with the temperature sensor t1, and each of the temperature characteristics Lt0, Lt1, and Lt2 is a place having the highest temperature. The temperature sensor t1 is substantially at the center of the semiconductor elements s1 to s4, and is arranged at a position where heat concentrates. It is desirable to install the temperature sensor t1 at a position close to the position where the surface temperature of the heat dissipation structure 102 is the highest or highest during the operation of the semiconductor power conversion circuit 101.

  Ltb1 to Ltb3 shown in FIG. 4 indicate the temperature characteristics when the cooling device f2 fails and stops in the temperature characteristics Lt2 shown in FIG. When the cooling device f2 is stopped, the surface temperature distribution of the heat dissipation structure 102 is biased. As the continuous operation time of the semiconductor power conversion circuit 101 elapses, the temperature in the vicinity of the semiconductor elements s3 and s4 rises in the order of Ltb1, Ltb2, and Ltb3, and at the stage of Ltb2, the highest temperature in Ltb2 is the temperature. The threshold value Tth1 has been reached. In Ltb2, the temperature detected by the temperature sensor t1 is tpb1.

  Since the detected temperature tpb1 is lower than the temperature threshold Tth1, if the temperature threshold is kept at Tth1, the semiconductor elements s3 and s4 fail due to overheating. Therefore, when the detected temperature tpb1 is registered in advance in the power conversion control circuit 105 as the second temperature threshold Tth2, and the cooling device f2 fails and stops, the power conversion control circuit 105 changes the temperature threshold from Tth1 to Tth2. Change to In the present embodiment, an example in which the cooling device f2 is stopped is shown, but when the cooling device f1 fails and stops, the temperature threshold value is similarly changed from Tth1 to Tth2 by the power conversion control circuit 105.

  Although not specifically described in the present embodiment, when the cooling devices f1 and f2 are stopped at the same time, it is not necessary to change the setting with the temperature threshold Tth1 because there is no bias in the surface temperature distribution of the heat dissipation structure 102. Absent. However, since all the cooling devices are stopped, there is a concern that the temperatures of the semiconductor elements s1 to s4 rapidly increase. Further, since the surface temperature distribution of the heat dissipation structure 102 is biased unless the cooling devices f1 and f2 are stopped simultaneously, in such a case, it is desirable to change the temperature threshold from Tth1 to Tth2.

  As described above, the semiconductor power conversion device 100 according to the present embodiment has a temperature sensor without immediately stopping the semiconductor power conversion circuit 101 by changing the temperature threshold even when one cooling device fails and stops. The operation can be continued without limiting the function of the semiconductor power conversion circuit 101 until the temperature detected by t1 reaches the changed temperature threshold. Moreover, since the number of temperature sensors can be reduced with respect to the number of cooling devices, it can be implemented at low cost.

Next, an embodiment of the present invention will be described with reference to FIGS.
FIG. 5 is a schematic diagram of a configuration example of the semiconductor power conversion device according to the present invention when there are four cooling devices. 6 is a mounting layout diagram of the semiconductor power conversion circuit, the heat dissipation structure, the cooling device, and the temperature sensor shown in FIG. FIG. 7 is a characteristic diagram of the temperature distribution of the temperature sensor unit shown in FIG. 6 and the heat dissipating structure surface in the left-right direction. FIG. 8 is a characteristic diagram of the temperature distribution on the surface of the heat dissipation structure when the cooling device f6 or f3 and f6 fails and stops in FIG.

A part of the description common to the first embodiment will be omitted.
As shown in FIG. 5, the semiconductor power conversion device 500 includes a semiconductor power conversion circuit 501, a heat dissipation structure 502, a cooling device monitoring circuit 503, a temperature monitoring circuit 504, a power conversion control circuit 505, a temperature sensor t2, and cooling devices f3 to f6. And is configured. Compared to the semiconductor power conversion device shown in FIG. 1, the number of cooling devices is doubled to four. The number of semiconductor elements constituting the semiconductor power conversion circuit 503 is also changed from four to eight. The power consumption and the heat generation amount of the semiconductor elements s5 to s12 are approximately the same or equivalent.

  The characteristic diagram of the temperature distribution shown in FIG. 7 is a characteristic diagram showing the temperature distribution when the number of cooling devices shown in FIG. 6 is four. Similarly to the characteristic diagram shown in FIG. 3, the horizontal axis of FIG. 7 shows the positional relationship among the cooling device, the semiconductor element, and the temperature sensor, and the vertical axis shows the temperature. Tth3 shown on the vertical axis is a temperature threshold when there is no abnormality in the cooling devices f3 to f6. The semiconductor power conversion circuit 501 is stopped at a temperature threshold Tth3 or more. Lt3 is a temperature characteristic indicating the surface temperature of the heat dissipation structure 502. tp3 is a detected temperature obtained by detecting the surface of the heat dissipation structure 502 with the temperature sensor t2, and is the highest temperature portion in the temperature characteristic Lt3. It is desirable to install the temperature sensor t2 at a location where the surface temperature of the heat dissipation structure 502 is the highest or close to the highest temperature.

  Ltb4 and Ltb5 shown in FIG. 8 are respectively the temperature characteristics when only the cooling device f6 fails and stops in the temperature characteristics Lt3 shown in FIG. 7 and when the cooling devices f3 and f6 both fail and stop. Show. Both Ltb4 and Ltb5 reach the temperature threshold Tth3 at the highest temperature. In tb4, the temperature detected by the temperature device t2 is tpb4, and in Ltb5, the temperature detected by the temperature device t2 is tpb5, and when two cooling devices fail from the detected temperature tpb4 when one cooling device fails. The detection temperature tpb5 is higher. For this reason, the temperature threshold set by the power conversion control circuit 505 is changed according to the number of failures of the cooling device, and the temperature threshold is increased as the number of failures increases. In the case of the present embodiment, the power conversion control circuit with the detected temperature tpb4 when only the cooling device f6 fails as shown in FIG. The temperature threshold value setting is changed from Tth3 to Tth4 or Tth5 by the power conversion control circuit 505 according to the failure status of the cooling device.

  As described above, the semiconductor power conversion device of the present embodiment changes the temperature threshold according to the number of failures of the cooling device, so that the operation of the semiconductor power conversion circuit 501 is more appropriately performed with respect to the number of failures of the cooling device. Can continue.

Next, an embodiment of the present invention will be described with reference to FIG.
FIG. 9 is a characteristic diagram of the temperature distribution on the surface of the heat dissipation structure when the cooling device f5 or f6 shown in FIG. 6 fails and stops. A part of the description common to the second embodiment is omitted.

  In the characteristic diagram of the temperature distribution shown in FIG. 9, the temperature when the cooling device f5 disposed closer to the temperature sensor t2 fails and stops compared to Ltb4 when the cooling device f6 shown in FIG. 8 fails. The characteristic is shown as Ltb6. Although both the Ltb4 and Ltb6 have one cooling device failure, the detected temperature detected by the temperature sensor t2 differs depending on the positional relationship between the temperature sensor t2 and the failed cooling device. The temperature detected by the temperature sensor t2 is tpb4 and tpb6 at Ltb4 and Ltb6, respectively, and the detection when the cooling device near the temperature sensor t2 fails than the detection temperature tpb4 when the cooling device far from the temperature sensor t2 fails The temperature tpb6 is higher.

  For this reason, the temperature threshold set by the power conversion control circuit 505 is changed according to the distance of the arrangement position of the temperature sensor and the failed cooling device, and the temperature threshold is increased as the distance is closer. In the case of the present embodiment, the detected temperature tpb4 when the cooling device f6 arranged far from the temperature sensor t2 from FIG. 9 fails is the detected temperature tpb4, and the detected temperature tpb6 when the cooling device f5 arranged near the temperature sensor t2 fails Is previously registered in the power conversion control circuit 505 as the temperature threshold Tth6, and the temperature threshold setting is changed from Tth3 to Tth4 or Tth6 by the power conversion control circuit 505 according to the failure state of the cooling device.

  As described above, the semiconductor power conversion device of the present embodiment changes the temperature threshold according to the distance between the position of the temperature sensor and the failed cooling device, so that The operation of the semiconductor power conversion circuit 501 can be continued appropriately.

Next, an embodiment of the present invention will be described with reference to FIG.
As shown in FIG. 10, the X-ray high voltage device 1008 includes a DC power supply 1001, a semiconductor power conversion device 1002 connected to the DC power supply 1001, a high voltage transformer 1003 connected to the semiconductor power conversion device 1002, Rectifier 1004 connected to high voltage transformer 1003, smoothing capacitor 1005 connected to rectifier 1004, tube voltage detector 1006 connected to smoothing capacitor 1005, tube voltage detector 1006 and semiconductor power converter 1002 , And a tube voltage feedback control circuit 1007 connected to the X-ray tube 1009 as a load. A semiconductor power conversion device 1002 is a device in which the semiconductor power conversion circuit 101 in the semiconductor power conversion device 100 shown in FIG. 1 is configured by an inverter circuit for an X-ray high voltage device.

  Next, the functions of the above components will be briefly described. The DC voltage generated by the DC power supply 1001 is converted into a high-frequency AC voltage by the semiconductor power converter 1002, and the converted high-frequency AC voltage is input to the primary winding of the high-voltage transformer 1003 and the secondary winding of the high-voltage transformer 1003. It is output as an alternating high voltage boosted from the line. The AC high voltage output from the high voltage transformer 1003 is rectified into a DC voltage by the rectifier 1004. The rectified DC voltage is smoothed by the smoothing capacitor 1005, and the smoothed DC voltage is supplied to the X-ray tube 1009. The tube voltage detector 1006 monitors the smoothed DC voltage. If the desired voltage cannot be supplied to the X-ray tube 1009, the semiconductor power conversion device 1002 is subjected to feedback control through the tube voltage feedback control circuit 1007.

  As described above, the semiconductor power conversion device of this embodiment can be used as a part of an X-ray high voltage device that supplies power to the X-ray tube. Even when the cooling device fails and stops, the operation of the semiconductor power conversion device can be continued, so that power can be stably supplied to the X-ray tube.

Next, an embodiment of the present invention will be described with reference to FIG.
A part of the description common to the fourth embodiment will be omitted. As shown in FIG. 11, the filament heating device 1104 includes a DC power source 1101, a semiconductor power converter 1102 connected to the DC power source 1101, and a filament heating transformer 1103. The filament 1105 is connected as a load. A semiconductor power conversion device 1102 is a device in which the semiconductor power conversion circuit 101 in the semiconductor power conversion device 100 shown in FIG. 1 is configured by an inverter circuit for a filament heating device.

  Next, the functions of the above components will be briefly described. The DC voltage generated by the DC power supply 1101 is converted into a high-frequency AC voltage by the semiconductor power converter 1102. The converted high-frequency AC voltage is transformed by a filament heating transformer 1103 to output an AC voltage. The AC voltage output from the filament heating transformer 1103 is supplied to the filament 1105.

  As described above, the semiconductor power conversion device of this embodiment can be used as a part of a filament heating device that supplies power to the filament of the X-ray tube. Even when the cooling device fails and stops, the operation of the semiconductor power conversion device can be continued, so that power can be stably supplied to the filament of the X-ray tube.

Next, an embodiment of the present invention will be described with reference to FIG.
FIG. 12 is a schematic diagram of an X-ray CT apparatus using the X-ray high voltage apparatus 1008 of the present invention. The X-ray CT apparatus 1200 includes a scan gantry unit 1201 and a console 1211. The scan gantry unit 1201 includes an X-ray tube 1009, a rotating disk 1202, a collimator 1203, an X-ray detector 1206, a data collection device 1207, a bed 1205, a gantry control device 1208, a bed control device 1209, An X-ray high voltage device 1008. An X-ray tube 1009 is a device that irradiates a subject placed on a bed 1205 with X-rays. The collimator 1203 is a device that limits the radiation range of X-rays emitted from the X-ray tube 1009.

  The rotating disk 1202 includes an opening 1204 for receiving a subject placed on a bed 1205, and is equipped with an X-ray tube 1009 and an X-ray detector 1206, and rotates around the subject. The X-ray detector 1206 is a device that measures the spatial distribution of transmitted X-rays by detecting X-rays that are placed opposite to the X-ray tube 1009 and transmitted through the subject, and rotates a number of X-ray detection elements. These are arranged in the rotation direction of the disk 1202, or two-dimensionally arranged in the rotation direction of the rotation disk 1202 and the rotation axis direction.

  The data collection device 1207 is a device that collects the X-ray dose detected by the X-ray detector 1206 as digital data. The gantry control device 1208 is a device that controls the rotation of the rotating disk 1202. The bed control device 1209 is a device that controls the vertical movement of the bed 1205. The X-ray high voltage device 1008 is a device that controls electric power input to the X-ray tube 1009. The console 1211 includes an input device 1212, an image calculation device 1213, a display device 1216, a storage device 1214, and a system control device 1215. The input device 1212 is a device for inputting a subject name, examination date and time, imaging conditions, and the like.

  The image calculation device 1213 is a device that performs CT processing on the measurement data sent from the data collection device 1207 and performs CT image reconstruction. The display device 1216 is a device that displays the CT image created by the image calculation device 1213. The storage device 1214 is a device that stores data collected by the data collection device 1207 and image data of CT images created by the image calculation device 1213. The system control device 1215 is a device that controls these devices, the gantry control device 1208, the bed control device 1209, and the X-ray high voltage device 1008.

  By controlling the power input to the X-ray tube 1009 by the X-ray high voltage device 1008 based on the imaging conditions input from the input device 1212, particularly the X-ray tube voltage and X-ray tube current, the X-ray tube 1009 The subject is irradiated with X-rays according to the imaging conditions. The X-ray detector 1206 detects X-rays irradiated from the X-ray tube 1009 and transmitted through the subject with a large number of X-ray detection elements, and measures the distribution of transmitted X-rays. The rotating disk 1202 is controlled by the gantry control device 1208, and rotates based on the photographing conditions input from the input device 1212, particularly the rotation speed. The bed 1205 is controlled by the bed control device 1209 and operates based on the photographing conditions input from the input device 1212, particularly the helical pitch.

  By repeating the X-ray irradiation from the X-ray tube 1009 and the measurement of the transmitted X-ray distribution by the X-ray detector 1206 along with the rotation of the rotating disk 1202, projection data from various angles is acquired. The obtained projection data from various angles is transmitted to the image calculation device 1213. The image calculation device 1213 reconstructs the CT image by performing back projection processing on the transmitted projection data from various angles. The CT image obtained by the reconstruction is displayed on the display device 1216.

  Next, operations in the case where an abnormality occurs in the cooling device in the X-ray high voltage apparatus 1008 used in the X-ray CT apparatus of the present invention will be described with reference to two methods with reference to FIGS. 13 and 14 are flowcharts for explaining the present embodiment.

  In the flowchart of FIG. 13, first, in step S1301, the surface temperature of the heat dissipation structure 102 is detected by the temperature sensor t1. The detected temperature Tp is monitored by the temperature monitoring circuit 104 and sent to the power conversion control circuit 105. Next, in step S1302, the power conversion control circuit 105 compares the temperature thresholds Tth1 and Tth2 registered in advance with the detected temperature Tp. Tth1 is a temperature threshold when there is no abnormality in the cooling device, and Tth2 is a temperature threshold when there is an abnormality in the cooling device. When the detected temperature Tp is less than the temperature threshold Tth2, the process returns to step S1301, when the detected temperature Tp is equal to or greater than the temperature threshold Tth1, the process proceeds to step S1303. When the detected temperature Tp is equal to or greater than the temperature threshold Tth2 and less than Tth1, the process proceeds to step S1304. Next, in step S1303, the semiconductor power conversion circuit 101 is stopped by the power conversion control circuit 105. Next, in step S1304, information on the detected temperature Tp is transmitted from the power conversion control circuit 105 to the system controller 1215, and the system controller 1215 displays a warning on the display device 1216 that the detected temperature Tp is equal to or higher than the temperature threshold Tth2. To do. Next, in step S1305, the cooling device monitoring circuit 103 monitors the states of the cooling devices f1 and f2, and notifies the power conversion control circuit 105 of the states. If there is no abnormality in the cooling device, the process returns to step S1301, and if there is an abnormality in the cooling device, the process proceeds to step S1303.

Next, the difference between the flowchart of FIG. 14 and the flowchart of FIG. 13 will be described.
In step S1401, the state of the cooling devices f1 and f2 is monitored by the cooling device monitoring circuit 103, and the state is transmitted to the power conversion control circuit 105. If there is no abnormality in the cooling device, the process proceeds to step S1404. If there is an abnormality in the cooling device, the process proceeds to step S1402. In step S1402, information regarding the state of the cooling device is transmitted from the power conversion control circuit 105 to the system control device 1215, and the system control device 1215 displays a warning on the display device 1216 that the cooling device is abnormal. In step S1403, the power conversion control circuit 105 compares the temperature threshold Tth2 registered in advance with the detected temperature Tp. If the detected temperature Tp is lower than the temperature threshold Tth2, the process returns to step S1301, and if the detected temperature Tp is equal to or higher than the temperature threshold Tth1, the process proceeds to step S1303. In step S1404, a comparison is made between the temperature threshold Tth1 registered in advance by the power conversion control circuit 105 and the detected temperature Tp. If the detected temperature Tp is lower than the temperature threshold Tth1, the process proceeds to step S1405. If the detected temperature Tp is equal to or higher than the temperature threshold Tth1, the process proceeds to step S1303. In step S1405, the power conversion control circuit 105 compares the temperature threshold Tth2 with the detected temperature Tp. If the detected temperature Tp is lower than the temperature threshold Tth2, the process returns to step S1301, and if the detected temperature Tp is equal to or higher than the temperature threshold Tth2, the process proceeds to step S1406. In step S1406, the system controller 1215 displays a warning on the display device 1216 that the detected temperature Tp is equal to or higher than the temperature threshold Tth2.

  As described above, the X-ray CT apparatus of the present embodiment limits the function without stopping imaging by the X-ray CT apparatus immediately by changing the temperature threshold even when an abnormality occurs in the cooling device. The operation can be continued without any problems.

Next, an embodiment of the present invention will be described with reference to FIG.
FIG. 15 is a schematic diagram of an X-ray diagnostic apparatus 1500 using the X-ray high voltage apparatus 1008 of the present invention. Since the operation of the X-ray high voltage apparatus 1008 is the same as that of the sixth embodiment, the description thereof is omitted. The X-ray diagnostic apparatus 1500 includes a top plate 1503 on which the subject 1502 is placed, an X-ray tube 1009 that irradiates the subject 1502 with X-rays, an aperture device 1501 that sets an X-ray irradiation area for the subject 1502, X-ray high-voltage apparatus 1008 that supplies power to 1009, X-ray detector 1504 that is disposed at a position facing X-ray tube 1009, detects X-rays that have passed through subject 1502, and X-ray detector 1504 An image processing unit 1505 that performs image processing on the output X-ray signal, an image storage unit 1506 that stores the X-ray image output from the image processing unit 1505, a display unit 1507 that displays an X-ray image, A control unit 1509 that controls each of the above-described components and an operation unit 1510 that instructs the control unit 1509 are provided. An X-ray tube 1009 is a device that irradiates a subject 1502 placed on a bed 1503 with X-rays. The aperture 1501 has a plurality of X-ray shielding lead plates that shield X-rays generated from the X-ray tube 1009, and each of the plurality of X-ray shielding lead plates is moved to irradiate the subject 1502 with X-rays. Determine the area. The X-ray detector 1504 is a device that detects an X-ray signal corresponding to the incident amount of X-rays irradiated from the X-ray tube 1009 and transmitted through the subject 1502. The image processing unit 1505 performs image processing on the X-ray signal output from the X-ray detector 1504, and outputs image-processed X-ray image data. The display unit 1507 displays the X-ray signal output from the image processing unit 1505 as an X-ray image of the subject 1502. The X-ray high voltage device 1008 is a device that controls electric power input to the X-ray tube 1009.

  As described above, the X-ray diagnostic apparatus according to the present embodiment uses the X-ray diagnostic apparatus by changing the temperature threshold even when an abnormality occurs in the cooling device, similarly to the X-ray CT apparatus shown in the sixth embodiment. The operation can be continued without stopping the shooting immediately and without restricting the functions.

  As mentioned above, although the Example of this invention was described, this invention is not limited to these.

  100, 500 Semiconductor power conversion device, 101, 501 Semiconductor power conversion circuit, 102, 502 Heat dissipation structure, 103, 503 Cooling device monitoring circuit, 104, 504 Temperature monitoring circuit, 105, 505 Power conversion control circuit, s1 to s12 semiconductor Element, t1, t2 Temperature sensor, f1 to f6 Cooling device, 1001, 1101 DC power supply, 1002, 1102 Semiconductor power conversion device shown in Fig. 1 composed of inverter circuit, 1003 High voltage transformer, 1004 Rectifier, 1005 Smoothing capacitor , 1006 tube voltage detector, 1007 tube voltage feedback control circuit, 1008 X-ray high voltage device, 1009 X-ray tube, 1103 filament heating transformer, 1104 filament heating device, 1105 filament, 1200 X-ray CT device, 1201 scan gantry , 1202 rotating disk, 1203 collimator, 1204 opening, 1205 couch, 1206 X-ray detector, 1207 data acquisition device, 1208 gantry control device, 1209 couch control device, 1211 console, 1212 ON Force device, 1213 image processing device, 1214 storage device, 1215 system control device, 1216 display device, 1500 X-ray diagnostic device, 1501 diaphragm device for setting X-ray irradiation area, 1502 subject, 1503 top plate, 1504 X-ray detection 1505 Image processing unit 1506 Image storage unit 1507 Display unit 1509 Control unit 1510 Operation unit

Claims (7)

  A semiconductor power conversion circuit having a plurality of semiconductor elements; a heat dissipation structure for radiating heat from the semiconductor power conversion circuit associated with the semiconductor power conversion circuit; two or more cooling devices for cooling the heat dissipation structure; and the cooling A cooling device monitoring circuit for monitoring an abnormality of the device, a temperature monitoring circuit for detecting the surface temperature of the heat dissipating structure with a smaller number of temperature sensors than the cooling device installed in the vicinity of some of the semiconductor elements, A power conversion control circuit having a plurality of temperature thresholds for stopping the operation of a semiconductor power conversion circuit and selecting and setting one temperature threshold from the plurality of temperature thresholds. When the cooling device monitoring circuit detects an abnormality in the cooling device, the temperature threshold value selected and set by the power conversion control circuit is lowered. Body power converter.   2. The semiconductor power conversion device according to claim 1, wherein a width for lowering the temperature threshold is controlled in accordance with the number of abnormalities detected in the cooling device by the cooling device monitoring circuit.   The semiconductor power conversion device according to claim 1, wherein the temperature threshold value is controlled to be lowered according to a distance between the temperature sensor and an arrangement position of the cooling device in which an abnormality is detected by the cooling device monitoring circuit.   2. The semiconductor power conversion circuit according to claim 1, wherein the semiconductor power conversion circuit is an inverter circuit, and is generated by the DC circuit that generates a DC voltage, the inverter circuit that converts the DC voltage generated by the DC power supply into a high-frequency AC voltage, and the inverter circuit. A high voltage transformer that boosts a high-frequency AC voltage to an AC high voltage, a rectifier that rectifies the AC high voltage generated by the high voltage transformer into a DC voltage, and a smoothing capacitor that smoothes the DC voltage generated by the rectifier. An X-ray high voltage apparatus characterized by the above.   2. The semiconductor power conversion circuit according to claim 1, wherein the semiconductor power conversion circuit is an inverter circuit, and is generated by the DC circuit that generates a DC voltage, the inverter circuit that converts the DC voltage generated by the DC power supply into a high-frequency AC voltage, and the inverter circuit. A filament heating apparatus comprising a filament heating transformer for transforming a high-frequency AC voltage.   An X-ray tube that irradiates the subject with X-rays, an X-ray detector that is disposed opposite to the X-ray tube and detects X-rays transmitted through the subject, and X-rays detected by the X-ray detector are collected as digital data X-ray CT apparatus comprising: a data acquisition apparatus that performs measurement processing sent out from the data acquisition apparatus to perform CT image reconstruction, and an input apparatus for inputting subject information The X-ray high voltage apparatus according to claim 4 is used for the X-ray high voltage apparatus used for the X-ray tube, or the filament heating apparatus according to claim 5 is used for the filament heating apparatus used for the X-ray tube. X-ray CT apparatus characterized by this.   An X-ray tube that irradiates the subject with X-rays, an X-ray detector that is disposed opposite to the X-ray tube and detects X-rays transmitted through the subject, and an X-ray image of the X-rays detected by the X-ray detector An X-ray diagnostic apparatus comprising: a display unit configured to display the X-ray high-voltage apparatus according to claim 4 or a filament used in the X-ray tube An X-ray diagnostic apparatus using the filament heating apparatus according to claim 5 as a heating apparatus.

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