A circuit for suppressing turn-off spike voltage of high-power power electronic devices
Patent Information
- Application Number
- CN202522477653.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-21
- Publication Date
- 2026-11-03
- Estimated Expiration
- 2035-11-21
AI Technical Summary
Existing absorption circuits suffer from poor absorption performance, high temperature rise, and easy damage when high-power power electronic devices are turned off.
A transient suppression diode is connected in parallel with the power module unit, and a heat dissipation unit is used to dissipate the heat generated by the transient suppression diode, thus forming a circuit to suppress the turn-off peak voltage of high-power power electronic devices.
It achieves good suppression of voltage spikes, has a simple structure and low cost, and has stable and reliable long-term working performance, protecting the power module unit from damage due to overvoltage breakdown.
Smart Images
Figure CN224935575U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of protection circuit technology, and in particular relates to a circuit for suppressing the turn-off peak voltage of high-power power electronic devices. Background Technology
[0002] The snubber circuit, also known as the buffer circuit, is an important protection circuit for power electronic devices. It is used not only for the protection of semi-controlled devices, but also plays a more important role in the application technology of fully controlled devices (such as GTR, GTO, power MOSFET and IGBT).
[0003] Traditional methods for improving the voltage stress experienced by power electronic devices during hard switching include RC absorption, capacitor absorption, varistors, and ceramic gas discharge tubes, each with its own advantages and disadvantages. When the turn-off current of the switching transistor is large (above 100A), the resulting turn-off spike is typically high and energy-intensive. If traditional absorption circuits are used, they suffer from poor absorption, high temperature rise, and susceptibility to damage. Utility Model Content
[0004] Therefore, the purpose of this utility model is to provide a circuit for suppressing the turn-off peak voltage of high-power power electronic devices, so as to fundamentally solve the problems of poor absorption effect, high temperature rise and easy damage of existing absorption circuits.
[0005] This utility model embodiment is implemented as follows: a circuit for suppressing turn-off peak voltage of high-power power electronic devices is provided, comprising: A power module unit, wherein the power module unit is connected to the load; A spike voltage suppression unit, comprising at least one transient suppression diode connected in parallel with the power module unit, for absorbing spike voltages generated when the power module unit is turned off; A heat dissipation unit is thermally coupled to the transient suppression diode to dissipate the heat generated by the transient suppression diode due to energy absorption.
[0006] In some implementations, the power module unit includes at least one power switch.
[0007] In some embodiments, a plurality of power switches are provided, and the plurality of power switches are connected in parallel.
[0008] In some embodiments, the power module unit further includes a plurality of drive resistors, each of which is connected to the gate of each power switch.
[0009] In some embodiments, the power module unit further includes a plurality of pull-down resistors, each of which is connected to the gate and source of each power switch transistor respectively.
[0010] In some embodiments, the power module unit further includes a freewheeling diode, which is connected to the gate and source of the power switch, respectively.
[0011] In some embodiments, a plurality of transient suppression diodes are provided, and the plurality of transient suppression diodes are connected in parallel.
[0012] In some embodiments, the heat dissipation unit includes an aluminum substrate having a first surface, and the transient suppression diode is mounted on the first surface.
[0013] In some embodiments, the heat dissipation unit further includes a heat sink, and the aluminum substrate has a second surface on which the heat sink is mounted.
[0014] In some embodiments, the radiator is a water-cooled radiator.
[0015] This utility model provides a circuit for suppressing the turn-off peak voltage of high-power power electronic devices. It has a simple structure and low cost. It only requires a transient suppression diode to suppress the peak voltage. It has a good peak voltage suppression effect, stable and reliable long-term working performance, and can effectively protect the power module unit from breakdown damage due to overvoltage. Attached Figure Description
[0016] Figure 1 This is a schematic diagram of the circuit for suppressing the turn-off peak voltage of high-power power electronic devices provided by the embodiments of this utility model; Figure 2 This is a circuit diagram of a circuit for suppressing the turn-off peak voltage of high-power power electronic devices, provided by an embodiment of this utility model. Detailed Implementation
[0017] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model. Furthermore, it should be understood that the specific embodiments described herein are merely for explaining this utility model and are not intended to limit this utility model.
[0018] In the description of this utility model, it should be understood that the terms "length", "width", "upper", "lower", "left", "right", "horizontal", "top", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.
[0019] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.
[0020] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, a link, or a connection that allows for mutual communication; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.
[0021] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.
[0022] The following disclosure provides numerous different embodiments or examples for implementing various structures of the present invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of the invention. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, examples of various specific processes and materials are provided in this invention, but those skilled in the art will recognize the application of other processes and / or the use of other materials.
[0023] refer to Figure 1 This utility model provides a circuit for suppressing turn-off spike voltage of high-power power electronic devices, comprising: A power module unit 100 is connected to a load. A spike voltage suppression unit 200 includes at least one transient suppression diode connected in parallel with the power module unit 100 to absorb the spike voltage generated when the power module unit 100 is turned off. A heat dissipation unit 300 is thermally coupled to the transient suppression diode to dissipate the heat generated by the transient suppression diode due to energy absorption.
[0024] The power module unit 100 is connected between the load and the power supply to control the current flowing to the load. Specifically, the input terminal of the power module unit 100 is connected to the power supply, and the output terminal of the power module unit 100 is connected to the load, forming the main power circuit. When the power module unit 100 is turned on, the current from the power supply flows to the load; when the power module unit 100 is turned off, the current from the power supply to the load is cut off.
[0025] The peak voltage suppression unit 200 includes at least one transient voltage suppressor diode (i.e., a TVS diode). The core characteristic of a transient voltage suppressor diode is avalanche breakdown; when the reverse voltage exceeds its breakdown voltage, the transient voltage suppressor diode rapidly conducts, allowing a large current to flow while limiting the voltage within a predetermined clamping voltage range. This response is extremely fast, typically within picoseconds, and can effectively absorb transient power up to several kilowatts.
[0026] Transient voltage suppressor diodes (TVS) operate in a high-resistance state during normal operation, having almost no impact on the circuit. When a transient overvoltage occurs in the circuit and exceeds its breakdown voltage, the TVS diode quickly transitions from a high-resistance state to a low-resistance state, forming a low-impedance path. This directs the large instantaneous current generated by the overvoltage to ground, while clamping the voltage within a safe range, protecting downstream circuitry from damage. Once the overvoltage dissipates, the TVS diode automatically returns to its high-resistance state and continues monitoring the circuit.
[0027] In this embodiment, when the power module unit 100 is turned off, a voltage spike is generated. At this time, the voltage spike exceeds the breakdown voltage of the transient suppression diode, causing the transient suppression diode to absorb the generated voltage spike. The heat generated by the transient suppression diode due to energy absorption is dissipated by the heat dissipation unit 300. After the power module unit 100 is turned off, the generated voltage spike disappears, and the transient suppression diode automatically returns to the high-resistance state to continue monitoring the circuit.
[0028] The circuit provided in this embodiment for suppressing the turn-off peak voltage of high-power power electronic devices has a simple structure and low cost. It only requires a transient suppression diode to suppress the peak voltage, and it has a good effect on suppressing the peak voltage. Its long-term working performance is stable and reliable, and it can effectively protect the power module unit 100 from breakdown damage due to overvoltage.
[0029] refer to Figure 2 In some specific embodiments of this application, the power module unit 100 includes at least one power switch. A power switch is a semiconductor device whose core function is to use voltage or current to switch the load current on and off. When the power switch is in the on state, its impedance is extremely low, equivalent to a closed switch, allowing a large current to flow; when the power switch is in the off state, its impedance is extremely high, equivalent to an open switch, cutting off the current.
[0030] refer to Figure 2 In some specific embodiments of this application, multiple power switching transistors are provided, and the multiple power switching transistors are connected in parallel. All the power switching transistors connected in parallel form a single switch, thereby providing a low-impedance, high-current path for the same load.
[0031] In this embodiment, all power switches form a bridge circuit. Power switches Q1, Q2, Q3, Q4, Q5, Q6, and Q7 are connected in parallel to form the upper half-bridge switch, which is connected to the AI+ connection point. Power switches Q8, Q9, Q10, Q11, Q12, Q13, and Q14 are connected in parallel to form the lower half-bridge switch, which is connected to the AI- connection point. The power supply to the load is controlled through this bridge circuit.
[0032] refer to Figure 2In some specific embodiments of this application, the power module unit 100 further includes a plurality of driving resistors, each of which is connected to the gate of each power switch.
[0033] The drive resistor serves the following functions: ① Suppressing oscillations: The gate of a power switch has parasitic inductance and capacitance, which can form an LC oscillation circuit. By setting a drive resistor, oscillations can be effectively suppressed, preventing severe oscillations in the gate voltage of the power switch caused by rapidly changing drive voltages, which could lead to abnormal turn-on, turn-off, or overheating. ② Adjusting switching speed: The drive resistor determines the charging and discharging speed of the gate capacitance of the power switch. The larger the resistance value of the drive resistor, the slower the switching speed; the smaller the resistance value, the faster the switching speed. By setting the drive resistor, a balance in switching speed can be achieved.
[0034] In this embodiment, driving resistor R1 is connected to the gate of power switch Q1, driving resistor R2 is connected to the gate of power switch Q2, driving resistor R3 is connected to the gate of power switch Q3, driving resistor R4 is connected to the gate of power switch Q4, driving resistor R5 is connected to the gate of power switch Q5, driving resistor R6 is connected to the gate of power switch Q6, driving resistor R7 is connected to the gate of power switch Q7, driving resistor R8 is connected to the gate of power switch Q8, driving resistor R9 is connected to the gate of power switch Q9, driving resistor R10 is connected to the gate of power switch Q10, driving resistor R11 is connected to the gate of power switch Q11, driving resistor R12 is connected to the gate of power switch Q12, driving resistor R13 is connected to the gate of power switch Q13, and driving resistor R14 is connected to the gate of power switch Q14.
[0035] refer to Figure 2 In some specific embodiments of this application, the power module unit 100 further includes a plurality of pull-down resistors, each of which is respectively connected to the gate and source of each power switch.
[0036] Pull-down resistors serve the following functions: ① Ensuring reliable turn-off: When the output of the driver chip is in a high-impedance state (e.g., when the chip is first powered on and not initialized, or in a reset state, or when a fault occurs), the gate of the power switch is in a floating state, making it susceptible to interference from external environmental noise and causing mis-turn-on, resulting in adverse consequences such as short circuits between the upper and lower bridge arms. By setting a pull-down resistor, a low-impedance discharge path to ground is provided for the gate, ensuring that the gate voltage is firmly pulled down to 0V when there is no effective drive signal, so that the power switch is stably and reliably in the turn-off state. ② Providing a discharge path for gate charge: During the turn-off process, pull-down resistors can help accelerate the release of gate charge.
[0037] In this embodiment, driving resistor R15 is connected to the gate and source of power switch Q1, driving resistor R16 is connected to the gate and source of power switch Q2, driving resistor R17 is connected to the gate and source of power switch Q3, driving resistor R18 is connected to the gate and source of power switch Q4, driving resistor R19 is connected to the gate and source of power switch Q5, driving resistor R20 is connected to the gate and source of power switch Q6, and driving resistor R21 is connected to the gate and source of power switch Q7. The driving resistors R22, R23, R24, R25, R26, R27, R28, and R28 are connected to the gate and source of power switch Q8, Q9, Q10, Q11, Q12, Q13, and Q14, respectively.
[0038] refer to Figure 2 In some specific embodiments of this application, the power module unit 100 further includes a freewheeling diode, which is connected to the gate and source of the power switch transistor. The freewheeling diode provides protection for the power switch transistor.
[0039] In this embodiment, freewheeling diodes D1, D2, D3, and D4 are provided. The anode of freewheeling diode D1 is connected to the gate of power switch Q1, the cathode of freewheeling diode D1 is connected to the cathode of freewheeling diode D2, and the anode of freewheeling diode D2 is connected to the source of power switch Q1. The anode of freewheeling diode D3 is connected to the gate of power switch Q8, the cathode of freewheeling diode D3 is connected to the cathode of freewheeling diode D4, and the anode of freewheeling diode D4 is connected to the source of power switch Q8.
[0040] refer to Figure 2 In some specific embodiments of this application, multiple transient suppression diodes are provided, and the multiple transient suppression diodes are connected in parallel.
[0041] The number of transient suppression diodes connected in parallel can be increased or decreased depending on the requirements of the power switch transistor's turn-off current, switching frequency, and temperature rise.
[0042] In this embodiment, power switching transistors Q1, Q2, Q3, Q4, Q5, Q6, and Q7 are connected in parallel, as are transient suppression diodes D5, D6, D7, D8, D9, D10, and D11. Power switching transistors Q8, Q9, Q10, Q11, Q12, Q13, and Q14 are also connected in parallel, along with transient suppression diodes D12, D13, D14, D15, D16, D17, and D18.
[0043] In some specific embodiments of this application, the heat dissipation unit 300 includes an aluminum substrate having a first surface, and the transient suppression diode is mounted on the first surface.
[0044] The transient suppression diode is placed in a blank position at the edge of the first surface of the aluminum substrate, so as not to change the original device layout on the aluminum substrate.
[0045] When the transient suppression diode absorbs the spike voltage generated when the power module unit 100 is turned off, the transient suppression diode generates heat, which is then conducted to the aluminum substrate.
[0046] In some specific embodiments of this application, the heat dissipation unit 300 further includes a heat sink, the aluminum substrate has a second surface, and the heat sink is mounted on the second surface.
[0047] The first and second surfaces of the aluminum substrate are opposite to each other; for example, the first surface of the aluminum substrate is the front surface, and the second surface is the back surface.
[0048] The heat sink is mounted in close contact with the second surface of the aluminum substrate. After the transient suppression diode absorbs the voltage spike generated when the power module unit 100 is turned off, the transient suppression diode generates heat, which is conducted to the aluminum substrate, and the aluminum substrate conducts the heat to the heat sink.
[0049] In some specific embodiments of this application, the heat sink is a water-cooled heat sink. The water-cooled heat sink mainly consists of a metal cold plate with internally machined flow channels, a pump, and an external heat exchanger. After the transient suppression diode absorbs the voltage spike generated when the power module unit 100 is turned off, the transient suppression diode generates heat, which is conducted to the aluminum substrate. The aluminum substrate then conducts the heat to the metal cold plate. Driven by the pump, the coolant circulates within the flow channels of the metal cold plate, directly absorbing the heat transferred from the aluminum substrate. The heated liquid flows to the external heat exchanger to release heat into the air, cools, and then circulates again, achieving heat dissipation through the liquid's efficient heat-carrying capacity.
[0050] In other embodiments, the heat sink is a finned heat sink. The finned heat sink consists of a metal substrate and numerous fins. Its operation is as follows: after the transient suppression diode absorbs the voltage spike generated when the power module unit 100 is turned off, the transient suppression diode generates heat, which is conducted to the aluminum substrate. The aluminum substrate then conducts the heat to the metal base, and finally distributes it to the individual fins. The fins significantly increase the contact area with the air, allowing heat to be carried away through natural convection or forced air cooling, thereby achieving heat dissipation.
[0051] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0052] The above-described embodiments are merely illustrative of several implementations of this utility model, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this utility model. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the appended claims.
Claims
1. A circuit for suppressing turn-off spike voltage of high-power power electronic devices, characterized in that, include: A power module unit, wherein the power module unit is connected to the load; A spike voltage suppression unit, comprising at least one transient suppression diode connected in parallel with the power module unit, for absorbing spike voltages generated when the power module unit is turned off; A heat dissipation unit is thermally coupled to the transient suppression diode to dissipate the heat generated by the transient suppression diode due to energy absorption.
2. The circuit for suppressing turn-off spike voltage of high-power power electronic devices according to claim 1, characterized in that, The power module unit includes at least one power switch transistor.
3. The circuit for suppressing turn-off spike voltage of high-power power electronic devices according to claim 2, characterized in that, The power switching transistors are provided in multiple ways, and the multiple power switching transistors are connected in parallel.
4. The circuit for suppressing turn-off spike voltage of high-power power electronic devices according to claim 3, characterized in that, The power module unit also includes multiple drive resistors, each of which is connected to the gate of each power switch.
5. The circuit for suppressing turn-off spike voltage of high-power power electronic devices according to claim 3, characterized in that, The power module unit also includes multiple pull-down resistors, each of which is connected to the gate and source of each power switch transistor.
6. The circuit for suppressing turn-off spike voltage of high-power power electronic devices according to claim 3, characterized in that, The power module unit also includes a freewheeling diode, which is connected to the gate and source of the power switch transistor respectively.
7. The circuit for suppressing turn-off spike voltage of high-power power electronic devices according to claim 1, characterized in that, Multiple transient suppression diodes are provided, and the multiple transient suppression diodes are connected in parallel.
8. The circuit for suppressing turn-off spike voltage of high-power power electronic devices according to claim 1, characterized in that, The heat dissipation unit includes an aluminum substrate having a first surface, and the transient suppression diode is mounted on the first surface.
9. The circuit for suppressing turn-off spike voltage of high-power power electronic devices according to claim 8, characterized in that, The heat dissipation unit further includes a heat sink, and the aluminum substrate has a second surface, with the heat sink mounted on the second surface.
10. The circuit for suppressing turn-off spike voltage of high-power power electronic devices according to claim 9, characterized in that, The radiator is a water-cooled radiator.