Semiconductor module and electrical energy conversion device

Abstract

Semiconductor module, comprising: a switching device (2a, 2b, 2c) having a gate contact point (3); an output unit (5a, 5b, 5c) having an output contact point (10) which is connected by a wire (11) to the gate contact point (3) of the switching device (2a, 2b, 2c) and outputs a control signal from the output contact point (10) to the switching device (2a, 2b, 2c); a temperature protection circuit (6) that detects a temperature and performs a protective operation; and a heat conduction structure (13) connected to the output contact point (10), extending from the output contact point (10) towards the temperature protection circuit (6) and conducting heat generated at the switching device (2a, 2b, 2c) to the temperature protection circuit (6).

Description

Background of the invention: Area

[0001] The present disclosure relates to a semiconductor module and an electrical energy conversion device which are configured to detect a temperature and to perform a protective operation. background

[0002] A new low-voltage integrated circuit (LVIC) mounted on an inverter module incorporates a temperature sensing function for overheating protection. Heat generated within the module is primarily produced by an IGBT chip. This heat is dissipated by a metal frame and encapsulated in resin to the LVIC's thermal protection circuitry (see, for example, JP 2011-199150 A). This thermal protection circuitry is essential to prevent phenomena such as motor overload or cooling fan failure, in which the module temperature can rise relatively slowly.

[0003] Further conventional semiconductor modules are known from US 2009 / 0 129 432 A1 and DE 101 25 694 A1. Summary

[0004] In transitional operating conditions, such as a motor stall operation or a short-circuit operation, where the boundary layer temperature Tj of the IGBT chip rises abruptly, a temperature deviation occurs between the boundary layer temperature Tj and the temperature Tlvic of the thermal protection circuit. Consequently, the thermal protection becomes inadequate, which has been a problem.

[0005] The present disclosure aims to solve the problem described above and to provide a semiconductor module and an electrical energy conversion device, each of which can achieve sufficient temperature protection.

[0006] A semiconductor module according to the present disclosure comprises: a switching device having a gate contact point; an output unit having an output contact point connected to the gate contact point of the switching device by a wire, and outputting a control signal from the output contact point to the switching device; a temperature protection circuit that detects a temperature and performs a protection operation; and a heat conduction structure connected to the output contact point, extending from the output contact point towards the temperature protection circuit and conducting heat generated at the switching device to the temperature protection circuit.

[0007] In the present disclosure, the heat conduction structure extending from the output contact point towards the thermal protection circuit is designed to conduct heat generated at the switching device to the thermal protection circuit. Accordingly, the temperature of the thermal protection circuit follows any temporary temperature changes in each of the switching devices, and as a result, the thermal protection circuit can accurately absorb an abrupt temperature increase of the switching device. Thus, even in operating modes such as motor stall or short-circuit operation, where the temperature of the switching device rises sharply, sufficient thermal protection can be achieved, preventing failure of the semiconductor module.

[0008] Other and further tasks, features and advantages of the invention will become more fully apparent from the following description. Brief description of the drawings Fig. Figure 1 is a top view showing a semiconductor module according to a first embodiment. Fig. Figure 2 is an enlarged top view of each output contact point and the temperature protection circuit according to the first embodiment. Fig. Figure 3 is a cross-sectional view showing each output contact point and the temperature protection circuit according to the first embodiment. Fig. Figure 4 is a circuit diagram that illustrates the temperature protection circuit. Fig. Figure 5 is a flowchart of a laser alignment operation. Fig. Figure 6 is a top view showing a first modification of the heat conduction structure according to the first embodiment. Fig. Figure 7 is a top view showing a second modification of the heat conduction structure according to the first embodiment. Fig. Figure 8 is a top view showing a third modification of the heat conduction structure according to the first embodiment. Fig. Figure 9 is a top view showing a semiconductor module according to a second embodiment. Fig. Figure 10 is a top view showing each switching device and the corresponding output unit according to a third embodiment. Fig. Figure 11 is an enlarged top view of each output contact point and the temperature protection circuit according to the third embodiment. Fig. Figure 12 is a block diagram showing the configuration of an electrical energy conversion device in which the semiconductor module according to the third embodiment is used. Description of embodiments

[0009] A semiconductor module and an electrical energy conversion device according to the embodiments of the present disclosure are described with reference to the drawings. The same components are identified by the same reference numerals, and the repeated description thereof may be omitted. First embodiment

[0010] Fig. Figure 1 is a top view showing a semiconductor module according to a first embodiment. The semiconductor module is an inverter module. An LVIC 1, used for low-pressure side control, controls a U-phase switching device 2a, a V-phase switching device 2b, and a W-phase switching device 2c. The switching devices 2a, 2b, and 2c are each, for example, an IGBT and have a gate contact 3. The LVIC 1 has an input unit 4, output units 5a, 5b, and 5c, a temperature protection circuit 6, a power circuit 7, an overcurrent protection circuit 8, and a power-loss protection circuit 9. The U-phase output unit 5a, the V-phase output unit 5b, and the W-phase output unit 5c are each provided for the U-phase, V-phase, and W-phase switching devices 2a, 2b, and 2c, respectively.

[0011] Input unit 4 transfers an external control signal to output units 5a, 5b, and 5c. Output units 5a, 5b, and 5c each have an output contact point 10. The output contact points 10 of output units 5a, 5b, and 5c are each connected by wires 11 to the gate contact points 3 of switching devices 2a, 2b, and 2c. The wires 11 are made of metal, such as Au, Ag, or Cu. Output units 5a, 5b, and 5c output control signals from the output contact points 10 to the switching devices 2a, 2b, and 2c.

[0012] The temperature protection circuit 6 detects a temperature and initiates a protective operation. This protective operation includes OT protection and VOT protection. In OT protection, operation of the output units 5a, 5b, and 5c of the respective phases is stopped if the temperature of the temperature protection circuit 6 has risen sharply. In VOT protection, the LVIC 1 does not perform self-protection; instead, an external microcomputer switches off a control input signal when it detects a rise in the output voltage VOT of the temperature protection circuit 6.

[0013] The power circuit 7 receives an external supply voltage and transfers this voltage to each circuit block of the LVIC 1. The overcurrent protection circuit 8 disconnects the switching devices 2a, 2b, and 2c when an overcurrent is drawn through an externally connected shunt resistor. The energy drop protection circuit 9 disconnects the switching devices 2a, 2b, and 2c when the supply voltage has dropped.

[0014] Fig. Figure 2 is an enlarged top view of each output contact point and the temperature protection circuit according to the first embodiment. Fig. Figure 3 is a cross-sectional view showing each output contact point and the thermal protection circuit according to the first embodiment. Each output contact point 10, the thermal protection circuit 6, and a heat conduction structure 13 are provided on a semiconductor substrate 12 of the LVIC 1. The heat conduction structure 13 is connected to the output contact point 10, extends from the output contact point 10 towards the thermal protection circuit 6, and overlaps with the thermal protection circuit 6. An insulating layer (not shown) is provided between the heat conduction structure 13 and the thermal protection circuit 6. Accordingly, the heat conduction structure 13 is not electrically but thermally connected to the thermal protection circuit 6. The heat conduction structure 13 is formed by aluminum sputtering but can also be formed from another metal.

[0015] Heat generated at the switching devices 2a, 2b, and 2c is conducted through the wires 11 to the output contact points 10 and then through the heat conduction structure 13 to the temperature protection circuit 6. Each wire 11 contributes not only to electrical conduction but also to heat conduction and therefore preferably has a diameter of 200 to 500 µm.

[0016] Fig. Figure 4 is a circuit diagram illustrating the temperature protection circuit. A constant current circuit (CC) and a temperature sensor diode (D1) are connected in series between a DC power source and a ground point. One or more temperature sensor diodes (D1) can be connected in series. An anode voltage (OTVF) of the temperature sensor diode (D1) is applied through a resistor (R1) to a negative input terminal of an operational amplifier (OA). A resistor (R2) is connected between an output terminal of the operational amplifier (OA) and the negative input terminal. A resistor (Ra), a laser calibration circuit (LT), and a resistor (Rb) are connected in series between a reference voltage (VREGOT) of a reference voltage circuit and a ground point. An output voltage (OTref) of the laser calibration circuit (LT) is applied to a positive input terminal of the operational amplifier (OA).

[0017] The operational amplifier OA amplifies inversely the anode voltage OTVF of the temperature sensor diode D1 and outputs the output voltage VOT, which is expressed by expression (1), as an analog temperature signal. VOT=OTref⋅(1+R2 / R1)−OTVF⋅R2 / R1

[0018] When the temperature of the temperature protection circuit 6 increases, the forward voltage of the temperature sensor diode D1 decreases, and the output voltage VOT of the operational amplifier OA increases.

[0019] The anode voltage OTVF and the reference voltage VREGOT vary due to device variance or similar factors. Therefore, the laser calibration circuit LT corrects the variance of the anode voltage OTVF and the reference voltage VREGOT, as described below. Fig. Figure 5 is a flowchart of a laser alignment operation.

[0020] First, the output voltage VOT and the reference voltage VREGOT are measured (step S1). It is then checked whether the reference voltage VREGOT lies within a variance standard (step S2). If the reference voltage VREGOT lies outside the standard, the module is determined to be a test-defective product. It is then checked whether the output voltage VOT lies within a variance standard (step S3). If the output voltage VOT lies outside the standard, the module is determined to be a test-defective product. It is then checked whether the output voltage VOT is a defined value (step S4). If the output voltage VOT is a defined value, the module is determined to be a test-not-defective product. Finally, the laser alignment circuit LT is connected to each of point A and point B.

[0021] The output voltage OTref, in which the laser calibration circuit LT is connected at point A and point B, is given by expression (2). OTref=VREGOT⋅Rb / (Ra+Rb)

[0022] The process then checks whether the output voltage VOT is greater than the defined value (step S5), and if the output voltage VOT is greater, the laser calibration circuit is disconnected at point A. In this case, the output voltage OTref is given by expression (3). A variable resistor RLT, with which an optimal output voltage VOT is obtained, is determined by expressions (1) and (3). OTref=VREGOT⋅Rb / (Ra+RLT+Rb)

[0023] If the output voltage VOT is less than the defined value, the laser calibration circuit is disconnected at point B. In this case, the output voltage OTref is given by expression (4). The variable resistor RLT, with which an optimal output voltage VOT is obtained, is determined by expressions (1) and (4). OTref=VREGOT⋅(RLT+Rb) / (Ra+RLT+Rb)

[0024] In this way, the resistance value of the variable resistor RLT, with which the output voltage VOT has an optimal value, is calculated from the measured value of the reference voltage VREGOT in order to determine an adjustment value of the variable resistor RLT, thereby performing the adjustment.

[0025] As described above, in the present embodiment, the heat conduction structure 13, which extends from each output contact point 10 towards the temperature protection circuit 6, is provided to conduct heat generated at the switching devices 2a, 2b, and 2c to the temperature protection circuit 6. Accordingly, the temperature Tlvic of the temperature protection circuit 6 follows a temporary change in the temperature Tj of each of the switching devices 2a, 2b, and 2c, and as a result, the temperature protection circuit 6 can accurately detect an abrupt rise in the temperature of the switching devices 2a, 2b, and 2c. Thus, even in an operating mode such as motor stall operation or short-circuit operation, in which the temperature of the switching devices 2a, 2b, and 2c rises sharply, it is possible to achieve sufficient temperature protection and prevent failure of the semiconductor module.

[0026] Additionally, temperature protection settings in a customer's system can be simplified if the semiconductor module according to the present embodiment is integrated into various types of products for consumer, industrial, or similar applications. Furthermore, the present embodiment can be achieved with an existing inverter module configuration, thus improving the accuracy of temperature sensing of the LVIC mounted on an inverter module at low cost.

[0027] Fig. Figure 6 is a top view showing a first modification of the heat conduction structure according to the first embodiment. Two straight heat conduction structures 13 overlap with the temperature protection circuit 6, and two other straight heat conduction structures 13 are provided on the side of the temperature protection circuit 6. When the majority of heat conduction structures 13 are provided in this way, the heat conduction performance to the temperature protection circuit 6 is further improved.

[0028] Fig. Figure 7 is a top view showing a second modification of the heat conduction structure according to the first embodiment. A heat conduction structure 13 surrounds the temperature protection circuit 6. The heat conduction structure 13 and the temperature protection circuit 6 are separated from each other, and heat is conducted from the heat conduction structure 13 through the semiconductor substrate 12 to the temperature protection circuit 6. The heat conduction structure 13 can contact a side surface of the temperature protection circuit 6 through an insulating layer. With such a heat conduction structure 13, heat generated at the switching devices 2a, 2b, and 2c can also be conducted to the temperature protection circuit 6.

[0029] Fig. Figure 8 is a top view showing a third modification of the heat conduction structure according to the first embodiment. Two heat conduction structures 13 surround the temperature protection circuit 6. When the majority of heat conduction structures 13 are provided in this way, the heat conduction efficiency to the temperature protection circuit 6 is further improved.

[0030] Each heat conduction structure 13 is located close to the entire temperature protection circuit 6. In the configuration of the temperature protection circuit 6 in Fig. 4 However, the device temperatures and characteristic values ​​of the temperature sensor diode D1, the laser calibration circuit LT, and the resistors Ra and Rb change with a change in the module temperature, which contributes to the output voltage VOT. Therefore, the heat conduction structure 13 is preferably provided close to these components. Second embodiment

[0031] Fig. Figure 9 is a top view showing a semiconductor module according to a second embodiment. The temperature protection circuit 6 is positioned closer to the output contact points 10 of the output units 5a, 5b, and 5c compared to other circuits, such as the power dissipation protection circuit 9 contained in the LVIC 1. Accordingly, the heat conduction efficiency to the temperature protection circuit 6 is further improved, and thus an abrupt temperature rise Tj of the switching devices 2a, 2b, and 2c can be detected more accurately. Third embodiment

[0032] Fig. Figure 10 is a top view showing each switching device and the corresponding output unit according to a third embodiment. A dummy contact point 14 is provided next to the output contact point 10 of the output unit 5a, 5b, or 5c. A dummy contact point 15 is provided next to the gate contact point 3 of the switching device 2a, 2b, or 2c.

[0033] The output contact points 10 of the output units 5a, 5b, or 5c are connected to the gate contact points 3 of the switching devices 2a, 2b, or 2c by electrically conductive wires 16. The dummy contact point 14 of the output unit 5a, 5b, or 5c is connected to the dummy contact point 15 of the switching device 2a, 2b, or 2c by a thermally conductive wire 17.

[0034] Fig. Figure 11 is an enlarged top view of each output contact point and the temperature protection circuit according to the third embodiment. The heat conduction structure 13 is connected to the dummy contact point 14. The heat conduction structure 13 extends from the dummy contact point 14 towards the temperature protection circuit 6 and conducts heat generated at each of the switching devices 2a, 2b, and 2c to the temperature protection circuit 6. The remaining configuration is the same as those of the first and second embodiments.

[0035] With the configuration according to the present embodiment, the temperature Tlvic of the temperature protection circuit 6 also follows a temporary change in the temperature Tj of the switching devices 2a, 2b, and 2c, similar to the first and second embodiments 1 and 2. Accordingly, the temperature protection circuit 6 can accurately detect an abrupt increase in the temperature of the switching devices 2a, 2b, and 2c. Thus, it is possible to achieve sufficient temperature protection and prevent failure of the semiconductor module in operating modes such as motor stall operation or short-circuit operation, in which the temperature of the switching devices 2a, 2b, and 2c rises sharply.

[0036] To achieve sufficient heat conduction, it is preferred that the diameter of each thermally conductive wire 17 is larger than the diameter of the corresponding electrically conductive wire 16 and is, for example, 200 to 500 µm. The thermally conductive wire 17 and the electrically conductive wire 16 are made of metal, such as Au, Ag, or Cu. However, the material of the thermally conductive wire 17 can be an electrically non-conductive element, such as thermally highly conductive fine ceramics, including AIN as a representative example. To further ensure efficient heat conduction, the heat conduction structure 13 is preferably connected not only to each dummy contact point 14 but also to each output contact point 10. Fourth embodiment

[0037] In the present embodiment, the semiconductor module according to one of the first to third embodiments described above is used in an electrical energy conversion device. The present disclosure is not limited to a specific electrical energy conversion device; rather, the following description is illustrated by a case in which the present disclosure is used in a three-phase inverter.

[0038] Fig. Figure 12 is a block diagram showing the configuration of an electrical energy conversion device into which the semiconductor module according to the third embodiment is inserted.

[0039] The electrical energy conversion device comprises a power source 100, a semiconductor module 101 for electrical energy conversion, an induction load 102, a control circuit 103, and a heat-dissipating fin 104. The power source 100 is a direct current (DC) power source and supplies DC energy to the semiconductor module 101. The power source 100 can be of any type and can, for example, be a DC system, a solar battery, or a storage battery, or it can be a rectification circuit or an AC / DC converter connected to an AC system. Alternatively, the power source 100 can be a DC / DC converter configured to convert DC energy output by a DC system into a predetermined electrical energy.

[0040] The semiconductor module 101 is a three-phase inverter connected between the power source 100 and the inductive load 102. The semiconductor module 101 converts direct current energy supplied by the power source 100 into alternating current energy and delivers the alternating current energy to the inductive load 102.

[0041] The Induction Load 102 is a three-phase electric motor driven by alternating current energy supplied by the semiconductor module for electrical energy conversion. The Induction Load 102 is not limited to a specific application but is an electric motor that can be mounted on various electrical instruments and used, for example, in a hybrid car, an electric vehicle, a rail vehicle, an elevator, or an air conditioner.

[0042] Details of the semiconductor module 101 are described below. The semiconductor module 101 comprises a switching device, a freewheeling diode, and an integrated circuit (IC) for controlling the switching device. When the switching device is activated, direct current (DC) energy supplied by the power source 100 is converted into alternating current (AC) energy and then supplied to the inductive load 102. Although the semiconductor module 101 can have various types of specific circuit configurations, according to the present embodiment, the semiconductor module 101 is a two-stage, three-phase full-bridge circuit and can be constructed from six switching devices and six freewheeling diodes connected antiparallel to the respective switching devices.The six switching devices form upper-lower arms by connecting each pair of switching devices in series, and each upper-lower arm provides the corresponding phase (U, V, and W phases) of the full bridge circuit. The output terminals of the respective upper-lower arms, in other words, three output terminals of the semiconductor module 101, are connected to the inductive load 102. The semiconductor module according to one of the first to third embodiments described above is used as the semiconductor module 101.

[0043] The control IC contained in the semiconductor module 101 generates a control signal that controls each switching device contained in the semiconductor module 101 in the same way. Specifically, the control signal for turning on the switching device or the control signal for turning off the switching device is output to a control electrode of each switching device according to a control signal from the control circuit 103, as described below. When the switching device is held on, the control signal is a voltage signal (“on” signal) equal to or higher than a threshold voltage of the switching device. When the switching device is held off, the control signal is a voltage signal (“off” signal) equal to or lower than the threshold voltage of the switching device.

[0044] The control circuit 103 controls each switching device of the semiconductor module 101, so that a desired electrical energy is supplied to the induction load 102.

[0045] In particular, a time ("on" time) at which each switching device of the semiconductor module 101 is to be switched on is calculated based on the electrical energy to be supplied to the inductive load 102. For example, the semiconductor module 101 can be controlled by a PWM controller, which modulates the "on" time of each switching device according to a voltage to be output. A control command (control signal) is output to the control IC contained in the semiconductor module 101, so that at any given time the "on" signal is output to a switching device to be switched on and the "off" signal is output to a switching device to be switched off. The control IC outputs the "on" signal or the "off" signal as the control signal to the control electrode of each switching device according to the control signal.

[0046] The heat dissipation fin 104 conducts heat generated by the operation of the semiconductor module 101 to the outside. Specifically, a connecting lubricant is applied between the heat dissipation fin 104 and the semiconductor module 101. Heat generated by the semiconductor module 101 is then dissipated to the outside via thermal conduction between the heat dissipation fin 104 and the connecting lubricant. The heat dissipation fin 104 can be attached to one or both sides of the semiconductor module for electrical energy conversion.

[0047] Since the semiconductor module according to one of the first to third embodiments is used as the semiconductor module 101 in the electrical energy conversion device according to the present embodiment, the accuracy of a temperature protection function of the electrical energy conversion device can be improved.

[0048] Although the present embodiment describes an example in which the present disclosure is used in a two-stage, three-phase inverter, the present disclosure is not limited thereto, and the present disclosure can be used in various types of electrical energy conversion devices. The electrical energy conversion device according to the present embodiment is a two-stage electrical energy conversion device, but it can be a three-stage or multi-stage electrical energy conversion device, or the present invention can be used in a single-phase inverter when electrical energy is supplied to a single-phase load. Alternatively, the present disclosure can be used in a DC / DC converter or an AC / DC converter when electrical energy is supplied to a DC load or the like.

[0049] The electrical energy conversion device in which the present disclosure is used is not limited to the case described above in which a load is an electric motor. For example, the electrical energy conversion device can be used as an energy device of an electric discharge machine, a laser machine, an induction cooker, or a contactless power supply system, or it can be used as a voltage regulator of a solar power generation system, an electrical storage system, or the like.

Claims

[1] Semiconductor module comprising: a switching device (2a, 2b, 2c) having a gate contact point (3); an output unit (5a, 5b, 5c) having an output contact point (10) which is connected by a wire (11) to the gate contact point (3) of the switching device (2a, 2b, 2c) and outputs a control signal from the output contact point (10) to the switching device (2a, 2b, 2c); a temperature protection circuit (6) that detects a temperature and performs a protective operation; and a heat conduction structure (13) connected to the output contact point (10), extending from the output contact point (10) towards the temperature protection circuit (6) and conducting heat generated at the switching device (2a, 2b, 2c) to the temperature protection circuit (6). [2] Semiconductor module according to claim 1, wherein the heat conduction structure (13) overlaps with the temperature protection circuit (6). [3] Semiconductor module according to claim 1, wherein the heat conduction structure (13) surrounds the temperature protection circuit (6). [4] Semiconductor module according to any one of claims 1 to 3, wherein the heat conduction structure (13) comprises a plurality of heat conduction structures. [5] Semiconductor module according to any one of claims 1 to 4, wherein the temperature protection circuit (6) is positioned closer to the output contact point (10) compared to other circuits. [6] Semiconductor module according to any one of claims 1 to 5, wherein the wire (11) has a diameter of 200 to 500 µm. [7] Semiconductor module comprising: a switching device (2a, 2b, 2c) comprising a gate contact point (3) and a first dummy contact point (15) provided next to the gate contact point (3); an output unit (5a, 5b, 5c) comprising an output contact point (10) connected by an electrically conductive wire (16) to the gate contact point (3) of the switching device (2a, 2b, 2c), and a second dummy contact point (14) provided next to the output contact point (10) and connected by a thermally conductive wire (17) to the first dummy contact point (15) of the switching device (2a, 2b, 2c), and outputting a control signal from the output contact point (10) to the switching device (2a, 2b, 2c); a temperature protection circuit (6) that detects a temperature and performs a protective operation; and a heat conduction structure (13) connected to the second dummy contact point (14), extending from the second dummy contact point (14) towards the temperature protection circuit (6) and conducting heat generated at the switching device (2a, 2b, 2c) to the temperature protection circuit (6). [8] Semiconductor module according to claim 7, wherein a diameter of the thermally conductive wire (17) is larger than a diameter of the electrically conductive wire (16). [9] Semiconductor module according to claim 7 or 8, wherein a material of the thermally conductive wire (17) is an electrically non-conductive element. [10] Semiconductor module according to one of claims 7 to 9, wherein the heat conduction structure (13) is connected to the output contact point (10). [11] Semiconductor module according to any one of claims 1 to 10, wherein the heat conduction structure (13) is made of metal and is not electrically connected to the temperature protection circuit (6). [12] Electrical energy conversion device comprising: the semiconductor module (101) according to any one of claims 1 to 11, which converts an input energy and outputs a converted energy; and a control circuit (103) which outputs a control signal to the semiconductor module for controlling the semiconductor module.

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