JP2009171842A - Power conversion apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a temperature detection method of a miniaturized and inexpensive semiconductor device, and to provide a compact and inexpensive power conversion apparatus. <P>SOLUTION: A temperature detection element 22 arranged near a component 8 with a power semiconductor device packaged therein and also near one of an emitter terminal and a collector terminal of the power semiconductor device, carries out the temperature detection for protecting the power semiconductor device. The temperature detection element 22 can be attached to a circuit board 13, so that electric insulation between a cooling fin 15 on which the power semiconductor device is arranged and the temperature detection element 22 is unnecessary, and a lead wire and man-hour for wiring the lead wire is unnecessary. Accordingly, protection of the power semiconductor device in a power conversion apparatus can be inexpensively achieved and compactification of the power conversion apparatus and shortening of assemble hour can be achieved. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a temperature detection technique for a semiconductor element, and more particularly to a temperature detection technique necessary for protecting a semiconductor element used in a power conversion device.

  In general, a semiconductor element has a switching loss. For this reason, a power semiconductor element (power semiconductor element) used in a power conversion device such as an inverter does not generate a considerable amount of heat. Therefore, an excessive current flows. If the cooling capacity cannot keep up, the temperature rises due to heat generation, and if it is left as it is, the allowable temperature may be exceeded and it may be destroyed by heat.

  Therefore, in order to prevent the semiconductor element from being destroyed by overheating in the power conversion device, it is usual to provide a thermal protection function, but for this purpose, it is necessary to detect the temperature of the semiconductor element. is there.

  Here, FIG. 5 shows a general configuration of an inverter device that is a typical example of a power conversion device. In this case, the entire device includes a forward conversion unit 100 and a smoothing unit 200 called a converter. Each block of an inverse conversion unit 300, a control unit 400, and an operation unit 500 called an inverter is provided as a main part.

  Then, the three-phase AC power supplied from the power source 600 such as a commercial power source is converted into DC power by the forward conversion unit 100 including, for example, a three-phase bridge diode circuit, and smoothed by the smoothing unit 200 including, for example, an electrolytic capacitor. The inverse conversion unit 300 converts the three-phase AC power U, V, and W having a desired frequency into a load 700 such as an induction motor IM.

  Next, FIG. 6 is a detailed view of the inverse conversion unit 300 when, for example, an IGBT (insulated gate bipolar transistor) is used as the power semiconductor element. 5, 6) are power semiconductor elements made of IGBT, and as shown in the figure, these are composed of an IGBT and a diode (flywheel diode) connected in reverse parallel thereto.

  At this time, in the inverse conversion unit 300, the DC + terminal P side is called the upper arm and the − terminal N side is called the lower arm. Here, the power semiconductor elements 4 to 6 of each arm are supplied from the control unit 400. By switching the gate drive signal, the upper arm and the lower arm are alternately switched and an inverse conversion operation is obtained.

  At this time, the current flowing in from the + terminal P flows from the collector of each power semiconductor element 1 to 3 of the upper arm through the emitter to the load 700 (in the case of the NPN type), and in the lower arm, each power semiconductor element 4 to 6 through the emitter and from the load 700 to the DC terminal N.

  Due to this current flow, in each of the power semiconductor elements 1 to 6, heat is generated mainly at the junction (junction) between the collector and the emitter. Therefore, for example, the power semiconductor element is overloaded. If the current flowing between the collector and the emitter of 1 to 6 becomes excessive, the temperature of the power semiconductor element rises, and if the limit is exceeded, the element is destroyed, and in some cases, the power converter itself is destroyed. A fear arises.

  Therefore, as described above, the control unit 400 detects the temperature of the power semiconductor element, and when the detected temperature reaches a predetermined temperature, for example, 80 ° C., the power semiconductor element is turned off ( OFF) to stop the heat generation of the power semiconductor element and suppress the temperature rise, thereby providing protection of the power semiconductor element and protection of the power conversion device.

  At this time, the prior art discloses a method of providing a temperature detection element in the cooling fin in which the power semiconductor element is arranged, and detecting the temperature of the cooling fin to obtain a detected value of the temperature of the semiconductor element (for example, (See Patent Document 1).

  Here, FIG. 7 shows an example of the arrangement of the power semiconductor elements in the prior art, where the components 7 to 12 (7, 8, 9, 10, 11, 12) are the power semiconductor elements 1 to 6 (FIG. 6). As shown in the figure, these are mounted on the element mounting surface of the cooling fin 15 in a desired arrangement form, and connections to the components 7 to 12 are circuits formed on the circuit board 13. The inverse transformation unit 300 is configured by the pattern.

  In FIG. 7, the circuit board 13 is shown separated from the cooling fins 15, but actually, the circuit board 13 is placed on the components 7 to 12 and the element mounting surface of the cooling fins 15 is mounted. The circuit board 13 is attached to the cooling fin 15 so as to cover.

  In the prior art of FIG. 7, as shown in the drawing, on the element mounting surface of the cooling fin 15, in the vicinity of the parts 7 to 12 formed of the packages of the power semiconductor elements 1 to 6, the temperature detection elements 16 to 21 are respectively provided. The lead wires 16a to 21a are drawn out from each of them and connected to the circuit board 13.

  At this time, as a desired arrangement form on the element mounting surface of the cooling fin 15 described above, the upper power semiconductor elements 1 and 2 are arranged in accordance with the arrangement state of the power semiconductor elements 1 to 6 in the circuit configuration of FIG. In general, the three parts 7, 8, 9 are arranged side by side, and the parts 10, 11, 12 of the power semiconductor elements 4, 5, 6 of the lower arm are arranged side by side on the lower side.

  At this time, when the power conversion device is put into use, the cooling fin 15 is generally assembled to the main body of the power conversion device so that its element mounting surface is substantially vertical. It is.

  On the other hand, in another conventional technique, in a power conversion device using a module in which a semiconductor element is enclosed, a method for detecting a temperature by enclosing a temperature detection element in the module together is disclosed (for example, , See Patent Document 1).

JP 2002-101668 A JP-A-11-142254

  The above prior art does not give consideration to the arrangement of the temperature detection elements, and has a problem in reducing the size and cost of the power conversion device having a thermal protection function.

  As described above, in the prior art described in FIG. 7, the temperature detection element is arranged on the cooling fin near the package of the power semiconductor element. In this case, only the temperature detection element is arranged on the cooling fin. Is required for the cooling fin.

  In addition, at this time, it is necessary to connect a lead wire for taking out the detection result by the temperature detection element, or to electrically insulate the temperature detection element from the cooling fin. It will be difficult to reduce the price.

  In addition, in the other prior art described above, as a result of enclosing the temperature detection element inside, the module is increased in size, and an extra terminal is required for the module. Therefore, downsizing and cost reduction become difficult.

  An object of the present invention is to provide a temperature detection method and a power conversion device for a semiconductor element suitable for downsizing and cost reduction.

The above object is a power conversion device using a semiconductor element for an inverse conversion unit,
There are a plurality of stages of semiconductor elements arranged side by side in a state where the power conversion device is used, and the semiconductor elements are arranged in the center of the uppermost stage of the plurality of stages. A temperature detecting element disposed at a distance capable of detecting a temperature change of a junction portion of the semiconductor element disposed at the center and in contact with a circuit pattern on a circuit board to which an emitter terminal of the semiconductor element is coupled This is achieved by performing temperature detection.

  At this time, even if the temperature detection element is arranged on the circuit board to which the emitter terminal is connected or connected to the junction of the semiconductor element through which the direct current on the N side flows, the above object is achieved. The above-described object can also be achieved by arranging the temperature detection element in contact with the circuit pattern of the circuit board.

  According to the above means, the temperature detecting element for detecting the temperature for preventing the destruction of the semiconductor element is disposed, for example, near the emitter terminal or the collector terminal of the power semiconductor element. At this time, since the temperature detecting element can be directly arranged on the circuit board on which the power semiconductor element is mounted, it is not necessary to electrically insulate from the cooling fin on which the power semiconductor element is arranged, and the man-hour for wiring is also reduced. Is possible.

  According to the present invention, since the temperature detection element is attached to the circuit board, the area of the cooling fin and the temperature of the power semiconductor element are detected by being electrically insulated from the cooling fin, and the detection result is transmitted to another board. This eliminates the need for parts and wiring man-hours.

  Therefore, according to the present invention, the provision of the thermal protection function to the semiconductor element can be realized at low cost, and the power conversion device can be downsized and the assembly time can be shortened.

It is a block diagram which shows one Embodiment of the power converter device provided with the temperature detection method and temperature detection function of the semiconductor element by this invention. It is an exploded view showing one embodiment of the present invention. It is explanatory drawing which shows the example of arrangement | positioning of the temperature detection element with respect to the power semiconductor element in one Embodiment of this invention. It is explanatory drawing which shows the other example of arrangement | positioning of the temperature detection element with respect to the power semiconductor element in one Embodiment of this invention. It is a block block diagram which shows an example of a power converter device. It is a circuit diagram which shows an example of the reverse conversion part in a power converter device. It is a block diagram which shows an example of the power converter device by a prior art.

  Hereinafter, a semiconductor device temperature detection method and a power conversion device having a temperature detection function according to the present invention will be described in detail with reference to embodiments shown in the drawings.

  FIG. 1 shows an embodiment of the present invention. In the figure, reference numeral 22 denotes a temperature detection element, and other components are the same as those of the prior art described with reference to FIG. 7-12 are arrange | positioned at the cooling fin 15, and the circuit board 13 is attached to this.

  At this time, a thermistor (registered trademark) is used as the temperature detection element 22 as an example, but this is not particularly described, but is the same as the case of the prior art. In this case, the circuit configuration of the inverse conversion unit 300 is the same as that of the prior art shown in FIG.

  However, in the embodiment of FIG. 1, as shown in FIG. 2, the temperature detecting element 22 is attached to the circuit board 13 instead of the cooling fin 15, and thus is attached to the cooling fin 15 at this point. This is different from the prior art. Here, FIG. 2 shows a state in which the circuit board 13 is separated from the cooling fins 15 as in FIG. 7 used in the description of the prior art.

  Moreover, in this embodiment, the temperature detection element is only the temperature detection element 22, that is, only one temperature detection element. Therefore, in this respect, a total of six temperature detection elements are provided for each of the power semiconductor elements 1 to 6. Is different.

  Here, as shown in FIG. 1, this one temperature detecting element 22 is packaged in the component 8 in the upper middle in the figure when the circuit board 13 is combined with the cooling fin 15. The circuit pattern of the circuit board 13 is formed in the vicinity of the collector terminal or emitter terminal of the power semiconductor element 2 (see FIG. 6) and in the vicinity of the circuit pattern to which these terminals are connected. It is attached to the surface that is on.

  Therefore, the control unit 400 detects the temperature of the temperature result element 22 based on the signal acquired from the temperature detection element 22, and the detected temperature is set to a predetermined determination temperature, for example, a determination temperature of 80 ° C. When the power reaches, the gates of all the power semiconductor elements 1 to 6 are turned off to cut off the energization between the collector and the emitter of each body element.

  As a result, since the heat generation of each of the power semiconductor elements 1 to 6 is stopped, thereafter, the temperature rise of the power semiconductor elements 1 to 6 is suppressed, and thereby the thermal protection of the power semiconductor elements and the entire power conversion device can be obtained. Here, next, according to this embodiment, all the power semiconductor elements 1 can be obtained without attaching the temperature detecting element 22 to the cooling fin 15 and by using only one temperature detecting element 22. The reason why the thermal protection of the entire power converter is obtained will be described.

  First, when a power semiconductor device is packaged, its collector and emitter terminals have a considerable cross-sectional area depending on the magnitude of the current value of the device, and therefore the heat conduction thereby is also quite large. Heat generated at the junction (junction) is efficiently transferred out of the package by the terminals.

  The heat efficiently led to the outside by the terminal in this way is transmitted to the circuit pattern because it is connected to the circuit pattern of the circuit board 13, and the temperature of the circuit board 13 is locally determined. Will be raised.

  Therefore, even if the temperature detecting element 22 is attached to the circuit board 13, it is disposed in the vicinity of the collector terminal or emitter terminal of the power semiconductor element 2 (see FIG. 6) and the circuit pattern to which these terminals are connected. If it is positioned in the vicinity, temperature detection equivalent to the case where the temperature detection element 22 is attached to the cooling fin 15 can be obtained.

  Next, in this embodiment, the cooling fin 15 is assembled to the main body of the power conversion device such that when the power conversion device is put into use, its element mounting surface is substantially vertical.

  Then, as in this embodiment, the upper arm power semiconductor elements 1, 2, and 3 are arranged side by side on the upper side, and the lower arm power semiconductor elements 4, 5, 6 are arranged on the lower side. When the parts 10, 11 and 12 are arranged side by side on the element mounting surface of the cooling fin 15, the temperature of the cooling fin 15 due to heat generated by each element becomes higher toward the upper side as shown by the arrow A. .

  At this time, since each of the power semiconductor elements 1 to 6 generates heat in the same manner, the heat concentrates in the center of the cooling fin 15 and the temperature rises so that the power on the upper side of the center of the cooling fin 15 increases. The temperature of the semiconductor element 2, that is, the component 8 is the highest.

  In this embodiment, since the temperature detection element 22 is disposed in the vicinity of the power semiconductor element 2, that is, the component 8, the temperature detection element 22 has a temperature of one of the six power semiconductor elements 1 to 6. This means that the temperature of the power semiconductor element 2 that is the highest is detected.

  Here, in order to protect the heat, the protection function is activated when the temperature of the element having the highest temperature among the plurality of power semiconductor elements attached to the same cooling fin reaches the temperature requiring the heat protection. It goes without saying that this is what you should do.

  Therefore, according to this embodiment, the temperature detection elements 22 are not attached to the cooling fins 15, and the heat of all the power semiconductor elements 1 to 6 and the entire power conversion device can be obtained with only one temperature detection element 22. Protection is gained.

  As a result, according to this embodiment, it is not necessary to arrange as many as six temperature detection elements 16 to 21 on the cooling fin 15 as in the prior art described in FIG. The number of steps required for installation and the number of steps required for wiring of the temperature detection element can be reduced, and parts such as electric wires necessary for the wiring can also be deleted.

  Next, the arrangement of the temperature detection element 22 in this embodiment will be described more specifically. As described above, the power semiconductor element 2 that is most affected by the temperature rise of other power semiconductor elements is packaged as described above. The circuit board 13 is arranged so as to be in the vicinity of the component 8 formed.

  Here, in this embodiment, the reason why the temperature detecting element 22 is provided in the vicinity of the power semiconductor element to be temperature detected is because it is desired to detect the temperature of the junction of the element. However, it is desirable that the vicinity of the collector terminal or the emitter terminal if possible.

  Here, FIG. 3 is an example in the case where the temperature detection element 22 is disposed in the vicinity of the emitter terminal 27 of the power semiconductor elements 1 to 6 (components 7 to 12). Next, FIG. 4 illustrates the temperature detection element. This is an example in which 22 is arranged in the vicinity of the collector terminal 28 of the power semiconductor elements 1 to 6 (components 7 to 12).

  On the other hand, the temperature detection element 22 receives the detection signal in the control unit 400, and is used for the thermal protection operation as described above. At this time, the control unit 400 is connected to the inverse conversion unit 300. Since the same potential is used as a reference, the detection result by the temperature detection element 22 also needs to be input to the control unit 400 as a signal based on the same potential as the control unit 400.

  At this time, since the inverse conversion unit 300 is controlled by the switching signal supplied from the control unit 400, the reference potential in the inverse conversion unit 300 and the control unit 400 is equal to the potential of the DC-terminal N in FIG. Therefore, in this case, the potential of the emitter terminals of the power semiconductor element 4, the power semiconductor element 5, and the power semiconductor element 6 is obtained.

  Therefore, as shown in FIG. 3, the temperature detecting element 22 is disposed in the vicinity of the emitter terminal 27, and in this case, the power semiconductor element is the power semiconductor element 4 or the power semiconductor element 5 in FIG. If it is one of the power semiconductor elements 6, the potential of the emitter terminal 27 becomes the same as the reference potential of the control unit 400. Therefore, the detection result by the temperature detection element 22 is directly transmitted to the control unit 400. Can be entered.

  On the other hand, if the power semiconductor element shown in FIG. 3 is any one of the power semiconductor element 1, the power semiconductor element 2, or the power semiconductor element 3 in FIG. 1, the potential of the emitter terminal 27 is 3 The same change as the potential of any one of the U, V, and W phases of the phase AC output is shown. In this case, the voltage becomes higher than the potential that is the reference in the control unit 400.

  Therefore, in this case, it is necessary to take an insulation distance defined in the specification standard required for the power conversion device between the temperature detection element 22 and the emitter terminal 27. In this case, the temperature detection element 22 has a power It becomes difficult to arrange in the vicinity of the emitter terminal 27 of the semiconductor element 1, the power semiconductor element 2, and the power semiconductor element 3.

  Therefore, in this case, the temperature detection element 22 is disposed in the vicinity of the emitter terminal 27 of the power semiconductor element 1, the power semiconductor element 2, or the power semiconductor element 3 so that the temperature can be detected more accurately. The detection output of the detection element 22 needs to be input to the control unit 400 in an electrically isolated state using an element such as a photocoupler.

  In addition, in this case, since the potentials of the emitter terminals 27 of the power semiconductor element 1, the power semiconductor element 2, and the power semiconductor element 3 fluctuate drastically during operation of the power converter, the output of the temperature detection element 22 is noise. It is necessary to pay attention to the fact that it is easily affected by

  Next, as shown in FIG. 4, when the temperature detection element 22 is arranged in the vicinity of the collector terminal 28, the potential of the collector terminal 27 of the power semiconductor element 1, the power semiconductor element 2, and the power semiconductor element 3 in FIG. Becomes the same high voltage as the DC + terminal P.

  Therefore, when the temperature detection element 22 is arranged in the vicinity of the collector terminal 28 of the power semiconductor element 1, the power semiconductor element 2, and the power semiconductor element 3 as described above, power conversion is performed between the temperature detection element 22 and the collector terminal 28. It is necessary to take the insulation distance defined in the specification standard that the device needs to acquire.

  When the insulation distance is taken in this way, it is difficult to arrange the temperature detecting element 22 in the vicinity of the power semiconductor element 1, the power semiconductor element 2, and the collector terminal 28 of the power semiconductor element 3.

  Therefore, in this case as well, the temperature detection element 22 is arranged in the vicinity of the collector terminal 28 of the power semiconductor element 1 or the power semiconductor element 2 or the power semiconductor element 3 so that the temperature can be detected more accurately. The detection output of the detection element 22 needs to be input to the control unit 400 in an electrically isolated state using an element such as a photocoupler.

  Further, if the power semiconductor element shown in FIG. 4 is any one of the power semiconductor element 4, the power semiconductor element 5 and the power semiconductor element 6 in FIG. 1, these collector terminals 28 have a three-phase AC output. This shows the same change as the potential of any of U, V, and W. In this case, the voltage becomes higher than the reference potential in the control unit 400.

  Therefore, in this case, it is necessary to take an insulation distance defined in the specification standard required for the power conversion device between the temperature detection element 22 and the collector terminal 28. In this case, the temperature detection element 22 It becomes difficult to arrange in the vicinity of the collector terminal 28 of the semiconductor element 4, the power semiconductor element 5, and the power semiconductor element 6.

  Therefore, in this case, the temperature detection element 22 is disposed in the vicinity of the collector terminal 28 of the power semiconductor element 4 or the power semiconductor element 5 or the power semiconductor element 6 so that the temperature can be detected more accurately. The detection output of the detection element 22 needs to be input to the control unit 400 in an electrically isolated state using an element such as a photocoupler.

  In addition, in this case, since the potential of the collector terminal 28 of the power semiconductor element 4, the power semiconductor element 5, and the power semiconductor element 6 fluctuates drastically during operation of the power converter, the output of the temperature detection element 22 is noise. It is necessary to pay attention to the fact that it is easily affected by

  Therefore, as an embodiment of the present invention, as shown in FIG. 3, the temperature detecting element 22 is arranged in the vicinity of the emitter terminal 27 of the power semiconductor elements 1 to 6, and then the temperature detecting element 22 is connected to the emitter terminal 27. It is preferable that the power semiconductor element arranged in the vicinity of is the power semiconductor element 2 shown in FIG.

  In the above embodiment, a power semiconductor element having a collector terminal and an emitter terminal is used. However, even a semiconductor element having another terminal name is close to the junction of the power semiconductor element. The advantage of the present invention in which the temperature of the power semiconductor element can be detected by arranging the temperature detection element in the vicinity of the terminal remains unchanged.

  Moreover, although the said embodiment demonstrated the case where the temperature detection element was one, multiple pieces may be arrange | positioned separately in the vicinity of each of the power semiconductor element.

  Furthermore, in the above-described embodiment, the power conversion device that can supply AC power of variable voltage variable frequency to the AC motor is described. However, AC power of variable voltage variable frequency can be supplied to the AC motor. Even if it is not a power conversion device, as long as it is a power conversion circuit using a power semiconductor element, the advantage of temperature detection of the power semiconductor element according to the present invention does not change.

1-6 Power semiconductor elements 7-12 Parts (parts in which power semiconductor elements 1-6 are packaged)
13 Circuit board of power converter
(Circuit board on which the control unit 400 and the like are mounted)
22 Temperature sensing element
(Temperature detection element arranged on the circuit pattern surface of the circuit board 13)
27 Emitter terminal of power semiconductor element 28 Collector terminal of power semiconductor element 100 Forward conversion unit (converter)
200 Smoothing part (capacitor)
300 Inverse converter (inverter)
400 Control unit 500 Operation unit 600 Power supply (commercial power supply)
700 load (IM (induction motor))

Claims (3)

A power conversion device using a semiconductor element for an inverse conversion unit,
There are a plurality of stages of semiconductor elements arranged side by side in a state where the power conversion device is used, and the semiconductor elements are arranged in the center of the uppermost stage of the plurality of stages. A temperature detecting element disposed at a distance capable of detecting a temperature change of a junction portion of the semiconductor element disposed at the center and in contact with a circuit pattern on a circuit board to which an emitter terminal of the semiconductor element is coupled A power converter that performs temperature detection.   2. The power conversion device according to claim 1, wherein the temperature detection element is arranged on a circuit board to which an emitter terminal is connected or connected to a junction of a semiconductor element in which a direct current on the N side flows.   The power conversion device according to claim 2, wherein the temperature detection element is disposed in contact with a circuit pattern of the circuit board.

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