JP2017085822A - Power converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology for collecting signal lines of a temperature sensor for measuring a temperature of a cooler into existing wiring in order in a power converter comprising the cooler.SOLUTION: The power converter comprises: a laminate cooler 3 in which a plurality of coolers is laminated while holding a power card 32a therebetween; a case 2 housing the laminate cooler 3 therein; a terminal block 4 supporting a bus bar 42a that is connected to the power card 32a, and including a current sensor for measuring a current of the bus bar 42a; and a temperature sensor 41 extending from the terminal block 4. A load is applied to the laminate cooler 3 towards an inner wall 21 of the case while bringing an end face of the laminate cooler 3 in a lamination direction into contact with the inner wall 21. A distal end 41c of the temperature sensor 41 including elements is connected to the inner wall 21. A signal line 45a of the current sensor and a signal line 45b of the temperature sensor extend from the terminal block 4 and are connected to a circuit board 6 that processes signals of the sensors.SELECTED DRAWING: Figure 4

Description

  The technology disclosed in the present specification relates to a power converter including a cooler.

  The power converter is used, for example, as a device that converts power source power of an electric vehicle into driving power of a traveling motor. The power converter includes a power card for converting power supply power. Since this power card generates heat, the power converter often includes a cooler.

  For example, Patent Document 1 discloses a power converter including a cooler. The power converter includes a stacked cooler in which a plurality of power cards and a plurality of coolers are alternately stacked in order to cool the power card. An elongated metal plate called a bus bar is connected to an output terminal provided in each of the plurality of power cards, and the plurality of bus bars are supported by a terminal block. The terminal block is also provided with a current sensor for measuring the current of each bus bar. Patent Document 2 discloses a technique in which a temperature sensor for measuring the temperature of a bus bar is incorporated into a current measuring instrument of the bus bar.

Japanese Patent Laying-Open No. 2015-033201 JP 2012-078328 A

  By the way, there is a case where it is desired to measure the temperature of the cooler that cools the power card. For example, the temperature of the cooler is used for controlling the flow rate of the refrigerant as the temperature of the refrigerant flowing in the cooler. However, if the temperature sensor for measuring the temperature of the cooler is provided independently, the signal line of the temperature sensor also needs to be provided independently. This signal line is independently connected to a circuit board for processing signals. Independent wiring complicates the layout within the power converter. In the present specification, a technique is provided in which signal lines of a temperature sensor for measuring the temperature of the cooler are arranged in an orderly manner, and an independent wiring for the temperature sensor is not required.

  The power converter disclosed in the present specification is a stacked cooler in which a plurality of coolers are stacked, and a stacked power card in which a semiconductor device is sealed between two adjacent coolers. A cooler, a case housing the stacked cooler, and a plurality of bus bars arranged adjacent to the stacked cooler and connected to terminals provided on each of the plurality of power cards. And a terminal block provided with a current sensor for measuring a current flowing through each bus bar, and a temperature sensor extending from the terminal block and having a tip including a temperature sensor element connected to the case. The load along the stacking direction is applied toward the inner wall while the end face of the stacking cooler along the stacking direction of the cooler is in contact with the inner wall of the case, and the tip of the temperature sensor is connected to the inner wall. Yes. The signal line of the current sensor and the signal line of the temperature sensor extend in parallel from the terminal block and are connected to a circuit board that processes the signal of the current sensor and the signal of the temperature sensor.

  As described above, a load in the stacking direction is applied to the stacked cooler toward the inner wall of the case. For this reason, the end surface of the stacked cooler is in close contact with the inner wall of the case. Therefore, if the temperature of the inner wall of the case is measured, the temperature of the cooler can be estimated. According to the above configuration, the terminal block is adjacent to the stacked cooler, the temperature sensor extends from the terminal block, and the tip including the temperature sensor element of the temperature sensor is connected to the inner wall of the case. Thereby, it becomes easy to assemble a temperature sensor for measuring the temperature of the cooler to the power converter. Further, the signal line of the current sensor extends from the terminal block to the circuit board, and the signal line of the temperature sensor extends from the terminal block in parallel with the signal line of the current sensor. Thereby, the signal line of the temperature sensor can be routed together with the signal line of the current sensor, and the signal line of the temperature sensor can be neatly connected to the circuit board together with the signal line of the current sensor with a simple structure. Details and further improvements of the technology disclosed in this specification will be described in the following “DETAILED DESCRIPTION”.

It is a top view of the power converter of an Example. It is a top view of a terminal block. It is a side view of a terminal block. It is sectional drawing in the IV-IV line of FIG.

  A power converter according to an embodiment will be described with reference to the drawings. The power converter of the embodiment is an inverter that converts direct current into alternating current. FIG. 1 is a plan view of an inverter 100 according to the embodiment. Inverter 100 is mounted on an electric vehicle (for example, a hybrid vehicle). Inverter 100 is a power converter that converts DC power of a vehicle-mounted battery into AC power suitable for driving a traveling motor, and includes an inverter circuit for converting DC power into AC power. Inverter 100 includes a plurality of semiconductor elements (so-called switching elements) constituting an inverter circuit. In order to drive the traveling motor, a large current flows through the inverter circuit. For this reason, the semiconductor elements constituting the inverter circuit generate heat. The inverter 100 can efficiently cool the plurality of semiconductor elements by collecting them. In the drawing, an XYZ coordinate system is shown, and in this specification, the configuration will be described using the XYZ coordinate system as appropriate.

  The inverter 100 includes a case 2, a stacked cooler 3, a terminal block 4, and a leaf spring 5. The case 2 is a case that accommodates the components 3, 4, and 5. In addition to the components 3, 4, and 5, the case 2 also accommodates components such as a connector for connecting a power cable extending from the in-vehicle battery and a capacitor connected to a power card described later. In FIG. 1, illustration of these components is omitted. In the inverter 100, the opening of the case 2 is closed by the cover after the components 3, 4, and 5 are accommodated in the case 2. In FIG. 1, illustration of the cover is omitted.

  The stacked cooler 3 includes four flat coolers 31a to 31d. The four coolers 31a to 31d are stacked such that the side surfaces having the largest area in the flat shape of each cooler (side surfaces whose normals face the Y-axis direction) face each other. A power card 32a for sealing the semiconductor element is sandwiched between two adjacent coolers 31a and 31b. Similarly, power cards 32b and 32c are sandwiched between two adjacent coolers 31b and 31c and between two adjacent coolers 31c and 31d, respectively. In other words, the four coolers 31a-31d and the three power cards 32a-32c are alternately stacked one by one. Each of the two coolers is in contact with both sides of each power card in the Y-axis direction. The Y axis coincides with the stacking direction of the coolers 31a-31d. An insulating plate 36 is sandwiched between each cooler and each power card.

  The four coolers 31a to 31d are connected by connecting pipes 33 and 34. The refrigerant supplied through the connecting pipe 33 is distributed to the four coolers 31a-31d through the connecting pipe 33. The heat generated in the power card 32a sandwiched between the coolers 31a and 31b is absorbed by the refrigerant passing through the coolers 31a and 31b. Similarly, the heat generated in the power cards 32b and 32c is absorbed by the refrigerant passing through each cooler in contact with each power card. The refrigerant that has passed through the four coolers 31 a to 31 d is collected in the connecting pipe 34 and discharged from the connecting pipe 34. As a result, the semiconductor elements sealed in the power cards 32a-32c are cooled.

  Further, one end face in the stacking direction of the stacked cooler 3, that is, an end face in the Y-axis positive direction is in contact with the inner wall 21 of the case 2. The other end surface of the stacked cooler 3, that is, the end surface in the Y-axis negative direction is in contact with the leaf spring 5. The leaf spring 5 is supported by a fixing pin that is fixed to the bottom surface of the case 2. That is, the laminated cooler 3 is sandwiched between the inner wall 21 of the case 2 and the leaf spring 5. A load along the stacking direction is applied to the stacked cooler 3 by a leaf spring 5. In other words, a load is applied to the laminated cooler 3 by the leaf spring 5 toward the inner wall 21 of the case 2. With this load, the adhesion between each cooler 31a-31d and each power card 32a-32c is enhanced, and the cooling efficiency of the stacked cooler 3 is enhanced.

  Each of the three power cards 32a to 32c seals two semiconductor elements connected in series, that is, a series circuit of two semiconductor elements. Each series circuit is connected in parallel with the in-vehicle battery. The connection point of the two semiconductor elements in each series circuit is connected to the traveling motor. And the inverter circuit of the inverter 100 is comprised by connecting three series circuits accommodated in each of the three power cards 32a-32c in parallel. Since the inverter circuit is a well-known technique, description thereof is omitted.

  The power cards 32a-32c have the same shape. The power card 32a includes three power terminals and a gate terminal. The three power terminals are provided on the side surface (that is, the side surface on the Z-axis positive direction side) located on the opening side of the case 2 of the power card 32a. The three power terminals are respectively connected to both ends of a series circuit of semiconductor elements and a connection point of the two semiconductor elements. In FIG. 1, a power terminal connected to a connection point of two semiconductor elements among the three power terminals, that is, a power terminal connected to the traveling motor is denoted by reference numeral 35 a. On the other hand, the gate terminal is provided on the side surface opposite to the side surface on which the three power terminals are provided (that is, the side surface on the Z-axis negative direction side). Therefore, the gate terminal is not visible in FIG. Similarly, the power cards 32b and 32c are each provided with three power terminals and a gate terminal. In FIG. 1, the power terminals connected to the connection points of the two semiconductor elements of the power cards 32b and 32c are denoted by reference numerals 35b and 35c, respectively.

  The terminal block 4 is a terminal block for connecting the power terminals 35a-35c of the three power cards 32a-32c to a traveling motor (not shown). As shown in FIG. 1, the terminal block 4 is disposed adjacent to the stacked cooler 3. The terminal block 4 and the stacked cooler 3 are arranged along a direction orthogonal to the stacking direction. The terminal block 4 includes a resin main body 40, three bus bars 42 a to 42 c, and a temperature sensor 41. The bus bar is an elongated metal plate. The three bus bars 42a to 42c extend along a direction orthogonal to the stacking direction (that is, the X-axis direction). One ends of the three bus bars 42a-42c are connected to the power terminals 35a-35c, respectively. The other ends of the three bus bars 42 a to 42 c are supported by the main body 40. The temperature sensor 41 extends in parallel with the three bus bars 42 a to 42 c from the main body 40, and a circular terminal 41 c is connected to the tip of the temperature sensor 41. The round terminal 41 c includes the temperature sensor element of the temperature sensor 41. The round terminal 41 c is connected to the inner wall 21 of the case 2.

  As shown in FIG. 1, the end wall of the stacked cooler 3 in the stacking direction (that is, the Y-axis direction) is in contact with the inner wall 21 of the case 2. A load in the stacking direction is applied to the stacked cooler 3 toward the inner wall 21 of the case 2. For this reason, the end surface of the laminated cooler 3 is in close contact with the inner wall 21 of the case 2. Therefore, the temperature of the inner wall 21 is the temperature of the stacked cooler 3, in particular, the temperature of the cooler 31a located at the end of the stacked cooler 3 in the stacking direction, that is, the temperature of the cooler 31a in contact with the inner wall 21. There is a correlation. As described above, the round terminal 41 c including the temperature sensor element of the temperature sensor 41 is connected to the inner wall 21. The temperature sensor element of the temperature sensor 41 detects the temperature of the inner wall 21. By detecting the temperature of the inner wall 21, the temperature of the cooler 31 a that is correlated with the inner wall 21 can be estimated. Typically, the temperature of the inner wall 21 measured by the temperature sensor 41 may be used as it is as the estimated temperature value of the cooler 31a.

  The terminal block 4 will be further described with reference to FIGS. FIG. 2 is a plan view of the terminal block 4. FIG. 3 is a side view of the terminal block 4. As shown in FIG. 2, the temperature sensor 41 includes a lead wire 41b extending in parallel with the three bus bars 42a-42c, and a round terminal 41c connected to one end of the lead wire 41b. The other end of the lead wire 41 b of the temperature sensor 41 is supported by the main body 40. As described above, the temperature sensor element 41a of the temperature sensor 41 is included in the round terminal 41c. In addition, as shown in FIG. 2, end portions 44 a to 44 c in the X axis positive direction of the three bus bars 42 a to 42 c are embedded in the main body 40. The terminal block 4 includes three current sensors 43a-43c for measuring the current flowing through each of the three bus bars 42a-42c. The three current sensors 43a-43c are current sensors for measuring a current flowing between the power card 32a-32c and the traveling motor. The current sensors 43a to 43c are, for example, magnetoelectric conversion elements that detect a magnetic field generated around the bus bar by a current flowing through the bus bar. The current sensor 43 a is disposed at a position facing the bus bar 42 a and is embedded in the main body 40. Similarly, the other current sensors 43b and 43c are arranged at positions facing the bus bars 42b and 42c.

  As shown in FIG. 3, the end portions 44 a-44 c of the three bus bars 42 a-42 c are exposed from the side surface of the main body 40 in the X axis positive direction. A power cable (not shown) extending from the traveling motor (not shown) is connected to the exposed portions of the end portions 44a-44c. As shown in FIG. 3, signal lines 45a, 45b, 45c, and 45d extend from the side surface of the main body 40 of the terminal block 4 in the negative Z-axis direction. The signal line 45a is composed of three signal lines extending in parallel, and each signal line is connected to each of the current sensors 43a-43c. The signal line 45 b extends in parallel with the signal line 45 a and is connected to the temperature sensor 41. The signal line 45c is a ground line common to the temperature sensor 41 and the current sensors 43a-43c, and is connected to the temperature sensor 41 and the current sensors 43a-43c. The signal line 45d is a line for supplying power to the current sensors 43a-43c, and is connected to the current sensors 43a-43c.

  With reference to FIG. 4, the configuration of inverter 100 will be further described. 4 is a cross-sectional view taken along line IV-IV in FIG. As shown in FIG. 4, the circuit board 6 is disposed outside the case 2 on the side where the bottom surface of the case 2 is located (that is, the Z-axis negative direction side). The circuit board 6 is accommodated in a board case attached to the bottom surface of the case 2. In FIG. 4, the illustration of the substrate case is omitted. A gate terminal extending in the Z-axis direction from the power cards 32a-32c and signal lines 45a, 45b, 45c, 45d extending in the Z-axis direction from the terminal block 4 are connected to the circuit board 6. In FIG. 4, reference numeral 37 is given to the gate terminal extending from the power card 32a. The gate terminal passes through a through hole 23 provided in the bottom surface of the case 2 and is connected to the circuit board 6. The signal lines 45 a, 45 b, 45 c, 45 d are also connected to the circuit board 6 through the through holes 24 provided on the bottom surface of the case 2. The circuit board 6 generates a PWM signal for controlling on / off of the semiconductor elements included in the power cards 32a to 32c, and supplies the PWM signal to each semiconductor element via the gate terminal. Further, the circuit board 6 acquires the signals of the current sensors 43a to 43c and the signal of the temperature sensor 41 from the signal lines 45a and 45b of the terminal block 4, and processes these signals.

  Moreover, as shown in FIG. 4, the round terminal 41c of the temperature sensor 41 is connected to the inner wall 21 of the case 2 by a screw 41d. The round terminal 41c is in close contact with the inner wall 21 by the fastening force of the screw 41d. As described above, the round terminal 41c includes the temperature sensor element 41a of the temperature sensor 41. The temperature sensor 41 can detect the temperature of the inner wall 21 by bringing the round terminal 41 c into close contact with the inner wall 21.

  The effect of the present embodiment will be described. As described above, the terminal block 4 is disposed adjacent to the stacked cooler 3, and the temperature sensor 41 is supported by the terminal block 4. The round terminal 41 c of the temperature sensor 41 is connected to the inner wall 21 of the case 2, which is in contact with the end surface in the stacking direction of the stacked cooler 3. Thereby, the temperature sensor 41 for measuring the temperature of the laminated cooler 3 can be easily assembled to the inverter 100. Further, the terminal block 4 includes signal lines 45 a of current sensors 43 a to 43 c, and the signal lines 45 a are connected to the circuit board 6. Since the temperature sensor 41 is supported by the terminal block 4, the signal line 45 b of the temperature sensor 41 is routed together with the signal line 45 a of the current sensors 43 a to 43 c and connected to the circuit board 6. Therefore, it is not necessary to route the signal line 45b of the temperature sensor 41 independently.

  Further, since the temperature sensor 41 is supported by the terminal block 4, the ground line of the temperature sensor 41 and the ground lines of the current sensors 43a to 43c can be shared by one signal line 45c. Thereby, the number of signal lines can be reduced. Further, since the temperature sensor 41 is supported by the terminal block 4, the temperature sensor 41 can be assembled to the inverter 100 without increasing the size of the inverter 100.

  The temperature sensor 41 is connected to the inner wall 21 of the case 2. For this reason, it is not necessary to connect the temperature sensor 41 directly to the cooler 31a to be measured, and it is not necessary to process the cooler 31a. Therefore, the temperature sensor 41 for measuring the temperature of the stacked cooler 3 can be easily assembled to the inverter 100 without processing the cooler 31a.

  Hereinafter, points to be noted regarding the technology shown in the embodiments will be described. The inverter 100 is an example of a “power converter”. For example, instead of the inverter 100, the technique of the present embodiment may be adopted in a power converter including an inverter circuit and a bidirectional converter circuit. In this case, one power card including a semiconductor element used for the bidirectional converter circuit is added, and one cooler is added corresponding to the power card. In this case, the number of coolers is five and the number of power cards is four. The number of coolers and the number of power cards in this embodiment are examples.

  Instead of the terminal block 4 for connecting the power card 32a-32c and the traveling motor, the technique of the present embodiment may be adopted for the terminal block for connecting the power card 32a-32c and the in-vehicle battery. In this case, the terminal block includes a current sensor for measuring a current flowing between the power card 32a-32c and the in-vehicle battery, and the temperature sensor 41 is supported by the terminal block. The signal line may be connected to the circuit board 6 together with the signal line of the current sensor.

  Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings can achieve a plurality of objects at the same time, and has technical usefulness by achieving one of the objects.

2: Case 3: Laminated cooler 4: Terminal block 5: Leaf spring 6: Circuit board 21: Inner walls 31a-31d: Cooler 32a-32c: Power card 35a-35c: Power terminal 41: Temperature sensor 41c: Round terminal 42a −42c: Bus bar 43a-43c: Current sensors 45a, 45b, 45c: Signal line 100: Inverter

Claims (1)

A stacked cooler in which a plurality of coolers are stacked, and a stacked cooler in which a power card sealing a semiconductor element is sandwiched between two adjacent coolers;
A case housing the stacked cooler;
A current sensor that is arranged adjacent to the stacked cooler and supports a plurality of bus bars connected to terminals provided in each of the plurality of power cards and measures a current flowing through each bus bar A terminal block comprising:
A temperature sensor extending from the terminal block and having a tip including a temperature sensor element connected to the case;
Has
A load along the stacking direction is applied to the stacked cooler toward the inner wall while the end face of the stacked cooler in the stacking direction of the cooler is in contact with the inner wall of the case,
The tip of the temperature sensor is connected to the inner wall;
The signal line of the current sensor and the signal line of the temperature sensor extend in parallel from the terminal block, and are connected to a circuit board that processes the signal of the current sensor and the signal of the temperature sensor. To power converter.

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