Semiconductor device, power module, inverter device, and electric vehicle

Abstract

In a case where the current value flowing in a thermistor increases, there is a problem that a voltage drop occurring in the thermistor increases and a clamping voltage generates a deviation. A semiconductor device of the present application is provided with a switching element subjected to on-off control, and a surge voltage protection circuit connected between a positive electrode side terminal of the switching element and a control terminal of the switching element, the surge voltage protection circuit being composed of a first Zener diode, a second Zener diode, and a temperature characteristic compensation element, the second Zener diode being connected in series with the first Zener diode, the temperature characteristic compensation element having a temperature coefficient having a polarity different from those of the first Zener diode and the second Zener diode, and the temperature characteristic compensation element being connected in parallel with the second Zener diode.

Description

Technical Field

[0001] This invention relates to semiconductor devices, power modules, inverter devices, and electric vehicles. Background Technology

[0002] Inverter units in electric vehicles such as hybrid electric vehicles or electric vehicles use switching elements that are controlled to switch on and off. These switching elements are designed to balance reduced switching time with surge voltage suppression. Therefore, a surge voltage protection circuit is provided between the positive terminal and the control terminal of the switching element. This surge voltage protection circuit is configured to operate at a voltage (clamping voltage) lower than the drain-source breakdown voltage of the switching element, thus protecting the switching element from breakdown when a surge occurs.

[0003] Patent document 1 discloses a load control device in which the cathode of a Zener diode Z1 is connected to the drain of a MOSFET, the anode of a diode is connected to the anode of the Zener diode Z1, a thermistor is connected between the cathode of the diode and the gate of the MOSFET, and a fixed resistor is connected in parallel with the thermistor.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2019-47416 Summary of the Invention

[0007] The problem the invention aims to solve

[0008] In the device described in Patent Document 1, when the current flowing through the thermistor increases, there is a problem that the voltage drop in the thermistor increases and the clamping voltage deviates.

[0009] Technical means to solve the problem

[0010] The semiconductor device of the present invention includes: a switching element controlled to switch on and off; and a surge voltage protection circuit connected between the positive terminal of the switching element and the control terminal of the switching element. The surge voltage protection circuit is composed of a first Zener diode, a second Zener diode, and a temperature characteristic compensation element. The second Zener diode is connected in series with the first Zener diode. The temperature coefficient of the temperature characteristic compensation element has a polarity different from that of the first Zener diode and the second Zener diode, and is connected in parallel with the second Zener diode.

[0011] The effects of the invention

[0012] According to the present invention, deviations in clamping voltage can be suppressed regardless of the current value. Attached Figure Description

[0013] Figure 1 This is a circuit configuration diagram of the semiconductor device according to the first embodiment.

[0014] Figure 2 A graph showing the temperature characteristics of the clamping voltage in the first embodiment.

[0015] Figure 3 A graph showing the current characteristics of the clamping voltage in the first embodiment.

[0016] Figure 4 This is a circuit diagram of the semiconductor device according to the second embodiment.

[0017] Figure 5 A graph showing the temperature characteristics of the clamping voltage in the second embodiment.

[0018] Figure 6 This is an external view showing the mounting structure of a semiconductor device.

[0019] Figure 7 A diagram showing the internal structure of a semiconductor device.

[0020] Figure 8 This is an external view of a power module with built-in semiconductor devices.

[0021] Figure 9 This is a diagram showing the internal structure of the power module.

[0022] Figure 10 A diagram showing the drive circuit of a motor using an inverter device.

[0023] Figure 11 A diagram illustrating the structure of an electric vehicle. Detailed Implementation

[0024] [First Implementation]

[0025] The embodiments of the present invention will now be described with reference to the accompanying drawings. However, the present invention is not limited to the following embodiments, and other known constituent elements can also be combined to realize the technical concept of the present invention. Furthermore, the same symbols are used to label the same elements in each figure, and repeated descriptions are omitted.

[0026] Figure 1 This is a circuit configuration diagram of the semiconductor device 100 according to this embodiment.

[0027] The switching element 110 is composed of a combination of a metal oxide film field-effect transistor (MOSFET) or an insulated gate bipolar transistor (IGBT) and a diode, and has a positive terminal 11, a negative terminal 12 and a control terminal 13.

[0028] The positive terminal 11 is connected to the positive side of an inverter device (not shown), the negative terminal 12 is connected to the negative side of an inverter device (not shown), and the control terminal 13 is connected to an inverter control device (not shown). The switching element 110 controls the conduction and disconnection of the current flowing from the positive terminal 11 to the negative terminal 12 according to the control signal input to the control terminal 13.

[0029] Surge voltage protection circuit 10 is connected between the positive terminal 11 of switching element 110 and the control terminal 13 of switching element 110. Surge voltage protection circuit 10 is typically configured by connecting diode 14 and a first Zener diode 15 in series. In this configuration, if the surge voltage generated between the positive terminal 11 and the negative terminal 12 due to the switching of switching element 110 exceeds the clamping voltage set by the Zener voltage of the first Zener diode 15, the first Zener diode 15 is energized, thereby allowing current to flow from the positive terminal 11 to the control terminal 13, causing the potential of the control terminal 13 to rise, thus protecting switching element 110 from surge voltage.

[0030] In this embodiment, the surge voltage protection circuit 10 is like Figure 1 As shown, it consists of diode 14, a first Zener diode 15, a second Zener diode 16, and a temperature characteristic compensation element 17. The second Zener diode 16 is connected in series with the first Zener diode 15. The temperature coefficient of the temperature characteristic compensation element 17 has a different polarity than that of the first Zener diode 15 and the second Zener diode 16, and the temperature characteristic compensation element 17 is connected in parallel with the second Zener diode 16. The temperature characteristic compensation element 17 is, for example, a thermistor.

[0031] The temperature coefficient of the temperature compensation element 17 has a different polarity than that of the second Zener diode 16. While the second Zener diode 16 has a positive temperature coefficient, the temperature compensation element 17 has a negative temperature coefficient. That is, when the temperatures of both the second Zener diode 16 and the temperature compensation element 17 rise, the Zener voltage of the second Zener diode 16 increases, while the resistance of the temperature compensation element 17 decreases. Conversely, when the temperatures of both the second Zener diode 16 and the temperature compensation element 17 decrease, the Zener voltage of the second Zener diode 16 decreases, while the resistance of the temperature compensation element 17 increases. As a result, when the temperatures of both the second Zener diode 16 and the temperature compensation element 17 are high, most of the current flowing in the surge voltage protection circuit 10 flows to the temperature compensation element 17; when the temperatures of both the second Zener diode 16 and the temperature compensation element 17 are low, most of the current flowing in the surge voltage protection circuit 10 flows to the second Zener diode 16.

[0032] Therefore, the clamping voltage of the second Zener diode 16 and the temperature characteristic compensation element 17 when the element temperature is high is calculated by the following formula (1), and the clamping voltage of the second Zener diode 16 and the temperature characteristic compensation element 17 when the element temperature is low is calculated by the following formula (2).

[0033] Vclamp=Vf+VZD1+VNTC··· (1)

[0034] Vclamp=Vf+VZD1+VZD2··· (2)

[0035] Here, Vclamp is the clamping voltage of surge voltage protection circuit 10, Vf is the forward voltage of diode 14, VZD1 is the Zener voltage of the first Zener diode 15, VNTC is the voltage drop that occurs in temperature characteristic compensation element 17, and VZD2 is the Zener voltage of the second Zener diode 16.

[0036] Figure 2 A graph showing the temperature characteristics of the clamping voltage in the first embodiment. Figure 2 In the diagram, the horizontal axis represents temperature, and the vertical axis represents voltage.

[0037] When the temperature of the second Zener diode 16 and the temperature characteristic compensation element 17 is low ( Figure 2 T1), the Zener voltage VZD2 of the second Zener diode 16 is low and the resistance value of the temperature characteristic compensation element 17 is large, so the clamping voltage Vclamp is the sum of the Zener voltage VZD1 of the first Zener diode 15 and the Zener voltage VZD2 of the second Zener diode 16, as shown in equation (2).

[0038] On the other hand, when the element temperatures of the second Zener diode 16 and the temperature characteristic compensation element 17 are high ( Figure 2 Since the Zener voltage VZD2 of the second Zener diode 16 is high and the resistance of the temperature characteristic compensation element 17 is small, the clamping voltage Vclamp, as shown in equation (1), is the sum of the Zener voltage VZD1 of the first Zener diode 15 and the voltage drop VNTC that occurs in the temperature characteristic compensation element 17. As a result, the variation of the clamping voltage with temperature change is suppressed compared to the general configuration that only uses the first Zener diode 15.

[0039] Figure 3 A graph showing the current characteristics of the clamping voltage in the first embodiment. Figure 3In the diagram, the horizontal axis represents the current flowing through the surge voltage protection circuit 10, and the vertical axis represents the voltage of the surge voltage protection circuit 10. Vclamp is the clamping voltage of the surge voltage protection circuit 10, Vf is the forward voltage of diode 14, VZD1 is the Zener voltage of the first Zener diode 15, VNTC is the voltage drop occurring in the temperature characteristic compensation element 17, and VZD2 is the Zener voltage of the second Zener diode 16.

[0040] When the temperatures of the second Zener diode 16 and the temperature compensation element 17 are high, the Zener voltage VZD2 of the second Zener diode 16 is high, and the resistance of the temperature compensation element 17 is low. Therefore, most of the current flowing in the surge voltage protection circuit 10 flows to the temperature compensation element 17. Consequently, with the increase of this current, the voltage drop VNTC in the temperature compensation element 17 increases. When the current I1 exceeds the Zener voltage VZD2, the second Zener diode 16 is energized. Thus, the increase in the clamping voltage Vclamp when the current flowing in the surge voltage protection circuit 10 increases can be suppressed.

[0041] [Second Implementation]

[0042] Figure 4 This is a circuit diagram of the semiconductor device 100' according to the second embodiment. (Regarding...) Figure 1 The same parts shown in the first embodiment are marked with the same symbols and their descriptions are omitted.

[0043] In the second embodiment, the surge voltage protection circuit 20 is composed of diode 14, first Zener diode 15, first clamping voltage compensation circuit section 20a, second clamping voltage compensation circuit section 20b, and ... nth clamping voltage compensation circuit section 20n connected in series.

[0044] The first clamping voltage compensation circuit section 20a is composed of a second Zener diode 16a connected in parallel with a temperature characteristic compensation element 17a. The second clamping voltage compensation circuit section 20b is composed of a third Zener diode 16b connected in parallel with a temperature characteristic compensation element 17b. The nth clamping voltage compensation circuit section 20n is composed of an nth Zener diode 16n connected in parallel with a temperature characteristic compensation element 17n. The polarity of the temperature coefficient of the temperature characteristic compensation elements 17a, 17b, ..., 17n is different from that of the first Zener diode 15, the second Zener diode 16a, and the nth Zener diode 16n.

[0045] In the second embodiment, the temperature at which the relationship between the Zener voltage VZD2a of the second Zener diode 16a in the first clamping voltage compensation circuit section 20a and the voltage drop VNTCa occurring in the temperature characteristic compensation element 17a changes is different from the temperature at which the relationship between the Zener voltage VZD2b of the third Zener diode 16b in the second clamping voltage compensation circuit section 20b and the voltage drop VNTCb occurring in the temperature characteristic compensation element 17b changes.

[0046] Figure 5 A graph showing the temperature characteristics of the clamping voltage in the second embodiment. Figure 2 In the diagram, the horizontal axis represents temperature, and the vertical axis represents voltage.

[0047] To simplify the explanation below, we will take the case where the surge voltage protection circuit 20 is composed of diode 14, first Zener diode 15, first clamping voltage compensation circuit section 20a and second clamping voltage compensation circuit section 20b connected in series as an example.

[0048] Temperature profiles of components in the first clamping voltage compensation circuit section 20a to the second clamping voltage compensation circuit section 20b Figure 5 When the temperature is T0 to T1 as shown, the voltage drop VNTCa in the temperature characteristic compensation element 17a is greater than the Zener voltage VZD2a of the second Zener diode 16a. Furthermore, the voltage drop VNTCb in the temperature characteristic compensation element 17b is greater than the Zener voltage VZD2b of the third Zener diode 16b. Therefore, the current flowing in the surge voltage protection circuit 20 flows through the second Zener diode 16a and the third Zener diode 16b. Consequently, the clamping voltage Vclamp is the sum of the Zener voltage VZD1 of the first Zener diode 15a, the Zener voltage VZD2a of the second Zener diode 16a, and the Zener voltage VZD2b of the third Zener diode 16b, calculated by the following equation (3).

[0049] Vclamp=Vf+VZD1+VZD2a+VZD2b··· (3)

[0050] When the component temperature of the first clamping voltage compensation circuit section 20a to the second clamping voltage compensation circuit section 20b is similar to... Figure 5When the voltage rises to T1~T2 as shown, the voltage drop VNTCa in the temperature characteristic compensation element 17a is greater than the Zener voltage VZD2a of the second Zener diode 16a. Furthermore, the voltage drop VNTCb in the temperature characteristic compensation element 17b is smaller than the Zener voltage VZD2b of the third Zener diode 16b. Therefore, the current flowing in the surge voltage protection circuit 20 flows through the second Zener diode 16a and the temperature characteristic compensation element 17b. Consequently, the clamping voltage Vclamp is the sum of the Zener voltage VZD1 of the first Zener diode 15a, the Zener voltage VZD2a of the second Zener diode 16a, and the voltage drop VNTCb in the temperature characteristic compensation element 17b, calculated by the following equation (4).

[0051] Vclamp=Vf+VZD1+VZD2a+VNTCb··· (4)

[0052] Temperature profiles of components in the first clamping voltage compensation circuit section 20a to the second clamping voltage compensation circuit section 20b Figure 5 When the temperature is T2 to T3 as shown, the voltage drop VNTCa in the temperature characteristic compensation element 17a is smaller than the Zener voltage VZD2a of the second Zener diode 16a. Furthermore, the voltage drop VNTCb in the temperature characteristic compensation element 17b is smaller than the Zener voltage VZD2b of the third Zener diode 16b. Therefore, the current flowing in the surge voltage protection circuit 20 flows through both the temperature characteristic compensation elements 17a and 17b. Consequently, the clamping voltage Vclamp is the sum of the Zener voltage VZD1a of the first Zener diode 15a, the voltage drop VNTCa in the temperature characteristic compensation element 17a, and the voltage drop VNTCb in the temperature characteristic compensation element 17b, calculated by the following equation (5).

[0053] Vclamp=Vf+VZD1+VNTCa+VNTCb··· (5)

[0054] As a result, when the component temperature of the first clamping voltage compensation circuit section 20a to the second clamping voltage compensation circuit section 20b changes, the clamping voltage switches multiple times, thus further suppressing the fluctuation of the clamping voltage. Although the description focuses on the first clamping voltage compensation circuit section 20a to the second clamping voltage compensation circuit section 20b, the same principle applies when multiple clamping voltage compensation circuit sections are connected in series, further suppressing the fluctuation of the clamping voltage.

[0055] Figure 6 This is an external view showing the mounting structure of the semiconductor device 100. The external view is based on... Figure 1 The description will use the appearance diagram of the semiconductor device 100 of the first embodiment shown in the figure as an example, but Figure 4The appearance of the semiconductor device 100' of the second embodiment shown in the figure is the same.

[0056] A positive terminal conductor 11a, made of copper or aluminum, which has low resistance and low thermal resistance, is disposed on the lowest surface of the substrate 30. A negative terminal conductor 12a, made of copper or aluminum, is disposed on the highest surface of the substrate 30.

[0057] Figure 7 The diagram showing the internal structure of the semiconductor device 100 has been omitted. Figure 6 The diagram shows the state of the negative terminal conductor 12a.

[0058] A positive-side terminal conductor insulation layer 11b is disposed on the upper surface of the positive-side terminal conductor 11a. The positive-side terminal conductor insulation layer 11b is made of insulating resin or ceramic, etc. A control signal layer 13a, etc., made of a conductor such as copper, is disposed on the upper surface of the positive-side terminal conductor insulation layer 11b. Furthermore, a switching element 110 is disposed on the upper surface of the positive-side terminal conductor 11a, and the positive-side terminal 11a of the positive-side terminal conductor 11a and the positive-side terminal 11a of the switching element 110 (see reference) Figure 1 The positive terminal of the switching element 110 is bonded together by solder or other positive terminal bonding material 11d. On the other hand, the negative terminal 12 of the switching element 110 (see reference) Figure 1 The negative terminal 12 (not shown) is bonded to the negative terminal 12 by a solder or other negative terminal bonding material 12d. At this time, by connecting multiple switching elements 110 in parallel, the maximum output current of the semiconductor element can be increased.

[0059] Control terminal 13 of switching element 110 (reference) Figure 1 The switching element 110 is connected to the control signal layer 13a via a control signal line 13d, such as a bonding wire. A diode 14, a first Zener diode 15, a second Zener diode 16, and a temperature compensation element 17 constituting the surge voltage protection circuit 10 are soldered onto the control signal layer 13a. That is, the switching element 110 and the surge voltage protection circuit 10 (diode 14, first Zener diode 15, second Zener diode 16, and temperature compensation element 17) are formed on the same substrate. In this case, by arranging the first Zener diode 15, the second Zener diode 16, and the temperature compensation element 17 close together in the semiconductor device 100, temperature deviations of the components can be reduced, thereby suppressing deviations in electrical characteristics.

[0060] Figure 8 This is an external view of a power module 200 with a built-in semiconductor device 100.

[0061] Signal lines from the internal semiconductor device 100 are grouped into a lower arm control signal line 13c and an upper arm control signal line 13b. The upper arm positive terminal 11c, the lower arm negative terminal 12c, and the upper surface of the upper arm negative terminal and lower arm positive terminal 18 are bonded to the heat sink 22 by a bonding material with low thermal resistance, such as solder. The sides are molded with resin 21 to prevent the ingress of foreign matter and to improve the withstand voltage.

[0062] Figure 9 The diagram showing the internal structure of the power module 200 has been simplified by removing certain elements. Figure 8 The diagram shows the state of the heat sink 22 and the resin 21.

[0063] Figure 9 The example shown includes two semiconductor devices 100-1 used as upper arms and two semiconductor devices 100-2 used as lower arms. The positive terminal conductor 11a of the upper arm (see reference) Figure 7 The upper arm's positive terminal 11c is connected via solder or other bonding materials. The upper arm's negative terminal (see reference) Figure 1 ) and the positive terminal of the lower arm (reference) Figure 1 Connected to the upper arm negative terminal and the lower arm positive terminal 18. The lower arm negative terminal (reference) Figure 1 The upper arm positive terminal 11c is connected to the lower arm negative terminal 12c. To reduce line inductance, the upper arm positive terminal 11c and the lower arm negative terminal 12c are positioned close to each other. (See reference for upper and lower arm control terminals.) Figure 1 They are respectively connected to the upper arm control signal line 13b and the lower arm control signal line 13c.

[0064] In the first and second embodiments, the surge voltage protection circuits 10 and 20 that suppress fluctuations in clamping voltage can be positioned closest to the switching element 110, thereby reducing the line inductance of the surge voltage protection circuits 10 and 20 and improving the response speed when clamping surge voltage. Furthermore, since the surge voltage protection circuits 10 and 20 that suppress fluctuations in clamping voltage do not require a microcomputer or other control device, they can be configured to be compact and can be installed inside the semiconductor devices 100 and 100' or the power module 200.

[0065] Figure 10 This is a diagram showing the drive circuit of the motor 400 using the inverter device 300.

[0066] The drive circuit includes an inverter device 300, an inverter control device 320, a motor 400, a position sensor 410, and a current sensor 420.

[0067] The inverter control device 320 performs PWM control on the inverter device 300 based on the torque command T* from the outside, the three-phase currents iu, iv, and iw detected by the current sensor 420, and the rotor position θ detected by the position sensor 410.

[0068] The inverter unit 300 is composed of semiconductor devices 100a to 100f. Each semiconductor device 100a to 100f is... Figure 1 The semiconductor device 100 shown in the image has a built-in switching element 110 and a surge voltage protection circuit 10. Alternatively, each of the semiconductor devices 100a to 100f is... Figure 4 The semiconductor device 100' with built-in switching element 110 and surge voltage protection circuit 20 shown in the image.

[0069] Semiconductor device 100a is disposed on the upper arm of the U phase, semiconductor device 100b is disposed on the lower arm of the U phase, semiconductor device 100c is disposed on the upper arm of the V phase, semiconductor device 100d is disposed on the lower arm of the V phase, semiconductor device 100e is disposed on the upper arm of the W phase, and semiconductor device 100f is disposed on the lower arm of the W phase.

[0070] Semiconductor devices 100a-100f turn switching elements 110 on or off according to switching signals generated by inverter control device 320, converting the DC voltage applied from the DC power supply into AC voltage. The converted AC voltage is applied to the stator of motor 400, generating three-phase AC current. This three-phase AC current causes motor 400 to generate a rotating magnetic field, causing the rotor to rotate.

[0071] Position sensor 410 detects the position of the rotor of motor 400 and outputs the detected rotor position θ to inverter control device 320. Current sensor 420 detects the current flowing to motor 400 and outputs the detected three-phase currents iu, iv, and iw to inverter control device 320.

[0072] Figure 11 A diagram illustrating the structure of an electric vehicle.

[0073] Figure 11 The electric vehicle shown has an inverter device 300 installed in the body 700 of a hybrid electric vehicle to drive the motor 400. The inverter device 300 has a semiconductor device 100 or semiconductor device 100' as described in the first and second embodiments, respectively.

[0074] The inverter device 300 operates according to the switching signal output from the inverter control device 320, performing power conversion from direct current to alternating current. The motor 400 is driven using the alternating current output from the inverter device 300. Thus, the electric vehicle moves using the driving force of the motor 400. Furthermore, the motor 400 operates not only as an electric motor that generates rotational driving force, but also as a generator that receives driving force to generate electricity. That is, the electric vehicle is a power system that uses the motor 400 as an electric generator.

[0075] A front axle 701 is rotatably supported at the front of the vehicle body 700, and front wheels 702 and 703 are provided at both ends of the front axle 701. A rear axle 704 is rotatably supported at the rear of the vehicle body 700, and rear wheels 705 and 706 are provided at both ends of the rear axle 704. A differential 711, which serves as a power distribution mechanism, is provided on the front axle 701 to distribute the rotational driving force transmitted from the engine 710 via the transmission 712 to the left and right front axles 701.

[0076] The output shaft of the engine 710 is mechanically connected to the output shaft of the motor 400, either directly or via the transmission 712. Thus, the rotational driving force of the motor 400 can be transmitted to the engine 710, and vice versa.

[0077] In motor 400, three-phase alternating current controlled by inverter device 300 is supplied to the stator coils of the stator, thereby causing the rotor to rotate and generating a rotational driving force corresponding to the three-phase alternating current. That is, motor 400 operates as an electric motor controlled by inverter device 300, and on the other hand, it operates as a generator that receives the rotational driving force of motor 710, causing the rotor to rotate and thereby inducing an electromotive force in the stator coils of the stator to generate three-phase alternating current.

[0078] The inverter device 300 converts the DC power supplied from the high-voltage battery 500, which is a high-voltage system (e.g., 300V) DC power source, into three-phase AC power, and controls the three-phase AC current flowing to the stator coil of the motor 400 according to the operating command value, which corresponds to the magnetic pole position of the rotor.

[0079] The three-phase alternating current generated by the motor 400 is converted into direct current by the inverter device 300 to charge the high-voltage battery 500. The high-voltage battery 500 is electrically connected to the low-voltage battery 723 via the DC-DC converter 724. The low-voltage battery 723 constitutes the low-voltage system (e.g., 12V) DC power supply of the automobile, used to power the starter motor 725 for initial starting (cold start) of the engine 710, as well as auxiliary equipment such as the radio and lights.

[0080] When the electric vehicle is stopped (idle stop mode) while waiting at traffic lights, the engine 710 is stopped. When restarting (hot start) upon resuming operation, the inverter device 300 drives the motor 400 to restart the engine 710. However, if the high-voltage battery 500 is undercharged or the engine 710 is not fully warmed up, it is preferable to continue driving the engine 710 even in idle stop mode. Furthermore, in idle stop mode, it is essential to ensure that auxiliary equipment such as the air conditioner compressor, which is driven by the engine 710, is properly powered. In this case, the motor 400, instead of the engine 710, can be used as the power source for these auxiliary equipment.

[0081] On the other hand, when the electric vehicle is in acceleration mode or high-load operation mode, the motor 400 is driven to assist the engine 710. Conversely, when in charging mode that requires charging of the high-voltage battery 500, the motor 400 generates electricity using the engine 710 to charge the high-voltage battery 500. Furthermore, during braking or deceleration of the electric vehicle, the motor 400 can generate electricity using the kinetic energy of the electric vehicle in regenerative mode to charge the high-voltage battery 500.

[0082] In the electric vehicle of this embodiment, the motor 400 that generates the driving force of the vehicle body 700 is controlled by the inverter device 300, which is protected by surge voltage protection circuits 10 and 20 and is not affected by surge voltage.

[0083] Therefore, the fluctuation of the clamping voltage Vclamp due to temperature changes in surge voltage protection circuits 10 and 20 is suppressed by the second Zener diode 16 and the temperature characteristic compensation element 17, thus reducing the tolerance of the clamping voltage relative to the withstand voltage of switching element 110 when designing surge voltage protection circuits 10 and 20. Therefore, regardless of the component temperature of surge voltage protection circuits 10 and 20, switching element 110 operates with a clamping voltage that ensures an appropriate tolerance relative to its withstand voltage, thereby shortening switching time and reducing switching losses.

[0084] As a result, the heat generated by the inverter device 300 during operation is reduced, enabling miniaturization of the cooling mechanism, as well as the inverter device 300 and the heat sink. Consequently, losses in the inverter device 300 are reduced, thereby reducing power consumption and improving the fuel efficiency of the electric vehicle.

[0085] Furthermore, by reducing the switching losses generated in the inverter device 300, the maximum switching frequency can be increased to a higher frequency without improving the cooling performance of the inverter device 300. As a result, the frequency of the voltage ripple generated in the DC voltage section of the inverter device 300 can be increased to a higher frequency, thus enabling the reduction and miniaturization of the input voltage smoothing capacitor connected in parallel with the power input terminals of the inverter device 300. Furthermore, the maximum output frequency of the inverter device 300 can be increased, thereby increasing the maximum speed of the motor 400. Consequently, the motor 400 is miniaturized due to its high-speed rotation, increasing its flexibility in installation in electric vehicles and thus expanding interior space.

[0086] Based on the implementation methods described above, the following effects are achieved.

[0087] (1) Semiconductor devices 100 and 100' include: a switching element 110, which is controlled to be switched on and off; and surge voltage protection circuits 10 and 20, which are connected between the positive terminal of the switching element 110 and the control terminal of the switching element 110. The surge voltage protection circuits 10 and 20 are composed of a first Zener diode 15, a second Zener diode 16, and a temperature characteristic compensation element 17. The second Zener diode 16 is connected in series with the first Zener diode 15. The temperature coefficient of the temperature characteristic compensation element 17 has a different polarity than that of the first Zener diode 15 and the second Zener diode 16, and the temperature characteristic compensation element 17 is connected in parallel with the second Zener diode 16. Thus, the deviation of the clamping voltage can be suppressed regardless of the current value.

[0088] This invention is not limited to the above-described embodiments. Other forms conceived within the scope of the technical concept of this invention are also included within the scope of this invention, as long as they do not impair the features of this invention.

[0089] Symbol Explanation

[0090] 10, 20… Surge voltage protection circuit, 11… Positive side terminal, 12… Negative side terminal, 13… Control terminal, 14… Diode, 15… First Zener diode, 16… Second Zener diode, 17… Temperature characteristic compensation element, 21… Resin, 22… Heat sink, 100, 100'… Semiconductor device, 100a… U-phase upper arm semiconductor device, 100b… U-phase lower arm semiconductor device, 100c… V-phase upper arm semiconductor device, 100d… V-phase lower arm semiconductor device, 100e… W-phase upper arm semiconductor device, 100f… W-phase lower arm semiconductor device, 110… Switching element, 300… Inverter unit, 320…Inverter control unit, 400…Motor, 410…Position sensor, 420…Current sensor, 700…Vehicle body, 701…Front axle, 702, 703…Front wheels, 704…Rear axle, 705, 706…Rear wheels, 710…Engine, 711…Differential, 712…Transmission, 723…Low-voltage battery, 724…DC-DC converter, 725…Starter, VZD1…Zener voltage of the first Zener diode, VZD2…Zener voltage of the second Zener diode, VNTC…Voltage drop of the temperature characteristic compensation element, Vclamp…Clamping voltage, i u …U-phase current detection value, i v …V-phase current detection value, i w …W-phase current detection value, T * …torque command value, ω…angular velocity, θ…rotor position.

Claims

1. A semiconductor device, characterized in that, have: Switching elements, which are controlled by on / off states; and A surge voltage protection circuit is connected between the positive terminal of the switching element and the control terminal of the switching element. The surge voltage protection circuit consists of a diode, a first Zener diode, a second Zener diode, and a temperature characteristic compensation element. The second Zener diode is connected in series with the first Zener diode. The temperature coefficient of the temperature characteristic compensation element has a different polarity than that of the first Zener diode and the second Zener diode. Furthermore, the temperature characteristic compensation element is connected in parallel with the second Zener diode.

2. The semiconductor device according to claim 1, characterized in that, The Zener voltage of the second Zener diode is lower than that of the first Zener diode.

3. The semiconductor device according to claim 1, characterized in that, The temperature characteristic compensation element is a thermistor.

4. A semiconductor device, characterized in that, include: A switching element that is controlled by on / off switching; as well as A surge voltage protection circuit is connected between the positive terminal of the switching element and the control terminal of the switching element. The surge voltage protection circuit consists of a diode, a first Zener diode, and multiple clamping voltage compensation circuit sections connected in series. The clamping voltage compensation circuit consists of a second Zener diode, which is different from the first Zener diode, and a temperature characteristic compensation element connected in parallel with the second Zener diode. The temperature coefficient of the temperature characteristic compensation element has a polarity different from that of the first Zener diode and the second Zener diode.

5. The semiconductor device according to claim 4, characterized in that, The temperature characteristic compensation element is a thermistor.

6. A power module, characterized in that, Equipped with a semiconductor device according to any one of claims 1 to 5, The switching element and the surge voltage protection circuit are formed on the same substrate.

7. An inverter device, characterized in that, The power module according to claim 6 converts DC voltage into AC voltage.

8. An electric vehicle, characterized in that, The inverter device according to claim 7 drives the motor by means of the AC voltage.

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