Driving method and system for improving reliability of power semiconductor grid

Abstract

The invention provides a driving method and system for improving the reliability of a power semiconductor gate. The method comprises the following steps: acquiring excitation current; generating a first break-over voltage and a second break-over voltage through the excitation current; if the first break-over voltage meets the break-over threshold voltage of the first transistor, the excitation current is transmitted to the energy storage capacitor for storage, so that the first terminal voltage of the power semiconductor circuit is controlled to be reduced; and if the second break-over voltage meets the break-over threshold voltage of the second transistor, the energy stored in the energy storage capacitor is transmitted to the first end point to supplement the excitation current so as to control the first end voltage of the power semiconductor circuit to rise. According to the invention, the problem of poor reliability of the grid electrode of the power device caused by wrong conduction due to the fact that the circuit layout in the prior art cannot effectively maintain the conduction and turn-off states of the power device is solved. According to the invention, the power device can maintain the on and off states more stably, and a short-circuit fault caused by wrong conduction of the power device is avoided.

Description

Technical Field

[0001] The present invention relates to the field of power device drive design, and in particular to a drive method and system for improving the reliability of a power semiconductor gate. Background Art

[0002] In new power systems, compared with traditional synchronous motors, grid-connected converters based on semiconductor power devices have complex structures and control methods. However, the power devices have poor shock resistance, which leads to a decrease in the reliability of traditional power systems. Taking the full-bridge converter based on SiC-MOSFET as an example, during high-speed switching, the unreliability of the gate drive circuit can easily lead to unstable gate drive voltage of the power device, which in turn leads to false conduction (the parasitic inductance in the driver loop has an inhibitory effect on current, which will cause the charging current (Miller current) of the Miller capacitor to be converted into the voltage of the gate-source junction capacitor when the switch tube is subjected to a sudden voltage change, thereby causing unstable gate-source voltage fluctuations).

[0003] At present, in order to improve the reliability of the gate driver and avoid short-circuit failures caused by unstable driving voltage and erroneous conduction, the main solutions adopted in the existing technology are: first, optimizing the layout of the driving circuit to reduce parasitic parameters; second, reducing the switching frequency of the converter to reduce the interference excitation source; third, adding a driving stabilization circuit (such as: Miller clamping circuit); finally, adding an additional control circuit to dynamically adjust the driving circuit and a series of other means, but the above four methods each have disadvantages, such as optimizing the layout and design of the driving circuit to minimize parasitic parameters requires a lot of time and manpower costs; reducing the switching frequency of the converter may hinder the miniaturization design of the equipment; adding a Miller clamping circuit is only applicable to 0V shutdown design, and this method cannot work for devices that recommend negative voltage shutdown; the newly added control circuit needs to occupy the control resources of the industrial control chip, and in addition, it is necessary to add control isolation and other measures, and the implementation of this method is relatively complicated; at the same time, the existing method cannot effectively maintain the on and off states of the power device in the circuit layout, resulting in the problem of poor reliability of the power device gate caused by erroneous conduction. Summary of the invention

[0004] In order to solve the above problems, the present invention proposes a driving method and system for improving the gate reliability of power semiconductors, which can effectively improve the gate reliability of power devices without reducing the switching frequency of the inverter and without using additional control circuits, so that the power devices can maintain the on and off states more stably, avoiding short-circuit failures caused by incorrect conduction of the power devices.

[0005] To achieve the above-mentioned object, an embodiment of the present invention provides a driving method for improving the reliability of a power semiconductor gate, which is applied to a driving circuit for improving gate reliability, comprising: a first transistor, a second transistor, an energy storage capacitor, a power semiconductor circuit and an external circuit;

[0006] The source of the first transistor and the source of the second transistor are electrically connected to form a first endpoint, the first end of the power semiconductor circuit is electrically connected to the first endpoint, the gate of the first transistor is electrically connected to the first end of the external circuit as the second endpoint, the gate of the second transistor is electrically connected to the second end of the external circuit as the third endpoint, the drain of the first transistor and the drain of the second transistor are electrically connected to form a fourth endpoint, the first end of the energy storage capacitor is electrically connected to the fourth endpoint, the third end of the external circuit is electrically connected to the second end of the energy storage capacitor, the second end of the power semiconductor circuit is electrically connected to the first end of the external circuit, and the third end of the power semiconductor circuit is electrically connected to the second end of the external circuit;

[0007] The driving method for improving the reliability of a power semiconductor gate comprises:

[0008] Based on the external circuit, obtain the excitation current;

[0009] Based on the second terminal and the third terminal, respectively generate a first conduction voltage and a second conduction voltage through the excitation current;

[0010] If the first on-voltage satisfies the on-threshold voltage of the first transistor, controlling the first transistor to be on and transmitting the excitation current to the energy storage capacitor for storage, so as to control the voltage at the first end of the power semiconductor circuit to decrease;

[0011] If the second on-voltage satisfies the on-threshold voltage of the second transistor, the second transistor is controlled to be on and the energy stored in the energy storage capacitor is transferred to the first terminal to supplement the excitation current so as to control the voltage at the first terminal of the power semiconductor circuit to increase.

[0012] An embodiment of the present invention proposes a driving method for improving the reliability of a power semiconductor gate. By adding a simple circuit consisting of a first transistor, a second transistor and an energy storage capacitor, two different on-state voltages are generated based on an excitation current obtained from an external circuit. The on and off of the first transistor and the second transistor are controlled according to the on-state voltage. When the first transistor is turned on, the energy generated by the excitation current is stored in the energy storage capacitor, so that the rising fluctuation of the voltage at the first end of the power semiconductor circuit is positively reduced. When the second transistor is turned on, the energy stored in the energy storage capacitor is transmitted to the first end to supplement the excitation current, so that the falling fluctuation of the voltage at the first end of the power semiconductor circuit is reversely reduced. By weakening the voltage fluctuation of the voltage at the first end of the power semiconductor circuit, the probability of erroneous conduction of the switch tube is effectively reduced, thereby improving the gate reliability of the power device.

[0013] Furthermore, the power semiconductor circuit includes: a first switch tube and a second switch tube;

[0014] The gate of the first switch tube is electrically connected to the first end of the power semiconductor circuit, the drain of the first switch tube is electrically connected to the source of the second switch tube, the source of the first switch tube is electrically connected to the third end of the power semiconductor circuit, and the gate of the second switch tube is electrically connected to the second end of the power semiconductor circuit;

[0015] Based on the pulse signal provided by the external circuit, the first switch tube and the second switch tube of the power semiconductor circuit are controlled to be turned on and off.

[0016] Furthermore, the external circuit includes: a driving chip and a suppression circuit; the suppression circuit includes a protection resistor and a parasitic inductor;

[0017] The driving chip is electrically connected to the second endpoint, the third endpoint and the fourth endpoint respectively; the first end of the protection resistor is electrically connected to the second endpoint and the driving chip respectively, the second end of the protection resistor is electrically connected to the first end of the parasitic inductance, and the second end of the parasitic inductance is electrically connected to the first endpoint;

[0018] The front stage of the driver chip is used to provide digital signals and digital power supply;

[0019] The rear stage of the driver chip is used to provide a three-level driving power supply;

[0020] The parasitic inductance is used to suppress current;

[0021] The protection resistor is used to protect the circuit.

[0022] Furthermore, obtaining the excitation current based on the external circuit includes:

[0023] Based on the fluctuation signal generated by the driving chip of the external circuit, the first switch tube and the second switch tube are controlled to be turned on and off;

[0024] Based on the turning on and off of the first switch tube and the second switch tube, an excitation current is output through the gate of the first switch tube.

[0025] Further, the generating a first conduction voltage and a second conduction voltage respectively through the excitation current based on the second endpoint and the third endpoint includes:

[0026] Based on the driving chip of the external circuit, the second terminal voltage and the third terminal voltage are respectively obtained;

[0027] The voltage difference between the second terminal voltage and the excitation current and the voltage difference between the third terminal voltage and the excitation current are calculated respectively to obtain a first conduction voltage and a second conduction voltage.

[0028] Furthermore, if the first on-voltage satisfies the on-threshold voltage of the first transistor, controlling the first transistor to be on and transmitting the excitation current to the energy storage capacitor for storage, so as to control the voltage at the first end of the power semiconductor circuit to decrease, comprises:

[0029] When the first on-voltage is greater than or equal to the on-threshold voltage of the first transistor, the first transistor is controlled to be on and the second transistor is controlled to be off;

[0030] transmitting the excitation current to the energy storage capacitor through the first transistor so that the energy of the excitation current is stored in the energy storage capacitor;

[0031] The energy of the excitation current is stored in the energy storage capacitor, so that the voltage at the first terminal of the power semiconductor circuit is reduced.

[0032] Furthermore, if the second on-voltage satisfies the on-threshold voltage of the second transistor, the second transistor is controlled to be on and the energy stored in the energy storage capacitor is transferred to the first terminal, the excitation current is supplemented to control the voltage at the first terminal of the power semiconductor circuit to increase, including:

[0033] When the second on-voltage is greater than or equal to the on-threshold voltage of the second transistor, the second transistor is controlled to be on and the first transistor is controlled to be off;

[0034] The energy stored in the energy storage capacitor is transmitted to the first terminal through the second transistor, so that the energy of the excitation current is supplemented to the first terminal voltage of the power semiconductor circuit;

[0035] The energy of the excitation current is supplemented to the first terminal voltage of the power semiconductor circuit, so that the first terminal voltage of the power semiconductor circuit is increased.

[0036] The embodiment of the present invention further provides a driving system for improving the reliability of a power semiconductor gate, comprising: an excitation current acquisition module, a conduction voltage generation module, a first control module and a second control module;

[0037] The excitation current acquisition module is used to acquire the excitation current based on the external circuit;

[0038] The conduction voltage generating module is used to generate a first conduction voltage and a second conduction voltage respectively through the excitation current based on the second endpoint and the third endpoint;

[0039] The first control module is used for controlling the first transistor to turn on and transmit the excitation current to the energy storage capacitor for storage if the first turn-on voltage meets the turn-on threshold voltage of the first transistor, so as to control the voltage at the first end of the power semiconductor circuit to decrease;

[0040] The second control module is used to control the second transistor to turn on and transfer the energy stored in the energy storage capacitor to the first terminal if the second turn-on voltage meets the turn-on threshold voltage of the second transistor, so as to supplement the excitation current and control the voltage at the first terminal of the power semiconductor circuit to increase.

[0041] An embodiment of the present invention proposes a driving system for improving the reliability of a power semiconductor gate. Two different on-voltages are generated based on an excitation current obtained from an external circuit by an excitation current acquisition module and an on-voltage generation module. The on and off of a first transistor and a second transistor are controlled according to the on-voltages. When the first transistor is turned on, the energy generated by the excitation current is stored in an energy storage capacitor through a first control module, so that the rising fluctuation of the voltage at the first end of the power semiconductor circuit is positively reduced. When the second transistor is turned on, the energy stored in the energy storage capacitor is transmitted to the first end of the excitation current through a second control module to supplement the excitation current, so that the falling fluctuation of the voltage at the first end of the power semiconductor circuit is reversely reduced. By weakening the voltage fluctuation of the voltage at the first end of the power semiconductor circuit, the probability of erroneous conduction of the switch tube is effectively reduced, thereby improving the gate reliability of the power device.

[0042] Further, the first control module is used to control the first transistor to turn on and transmit the excitation current to the energy storage capacitor for storage if the first turn-on voltage meets the turn-on threshold voltage of the first transistor, so as to control the voltage at the first end of the power semiconductor circuit to decrease, and also includes:

[0043] A first threshold determination unit, an energy storage unit and a first voltage control unit;

[0044] The threshold judgment unit is used for controlling the first transistor to be turned on and the second transistor to be turned off when the first turn-on voltage is greater than or equal to the turn-on threshold voltage of the first transistor;

[0045] The energy storage unit is used to transmit the excitation current to the energy storage capacitor through the first transistor, so that the energy of the excitation current is stored in the energy storage capacitor;

[0046] The first voltage control unit is used for reducing the voltage at the first terminal of the power semiconductor circuit by storing the energy of the excitation current in the energy storage capacitor.

[0047] Further, the second control module is used to control the second transistor to turn on and transfer the energy stored in the energy storage capacitor to the first end point if the second turn-on voltage meets the turn-on threshold voltage of the second transistor, and supplement the excitation current to control the voltage of the first end of the power semiconductor circuit to increase, and also includes:

[0048] a second threshold determination unit, an energy replenishment unit, and a second voltage control unit;

[0049] The second threshold judgment unit is used to control the second transistor to be turned on and the first transistor to be turned off when the second turn-on voltage is greater than or equal to the turn-on threshold voltage of the second transistor;

[0050] The energy supplement unit is used to transmit the energy stored in the energy storage capacitor to the first terminal through the second transistor, so that the energy of the excitation current is supplemented to the first terminal voltage of the power semiconductor circuit;

[0051] The second voltage control unit is used for increasing the voltage at the first terminal of the power semiconductor circuit by supplementing the energy of the excitation current to the voltage at the first terminal of the power semiconductor circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 A schematic diagram of a driving circuit of a driving method for improving the reliability of a power semiconductor gate provided by a certain embodiment of the present invention;

[0053] Figure 2 A schematic diagram of a driving circuit module structure of a driving method for improving the reliability of a power semiconductor gate provided by a certain embodiment of the present invention;

[0054] Figure 3 A schematic flow chart of the steps of a driving method for improving the reliability of a power semiconductor gate provided by a certain embodiment of the present invention;

[0055] Figure 4A schematic diagram of a first transistor conduction circuit structure of a driving method for improving the reliability of a power semiconductor gate provided by a certain embodiment of the present invention;

[0056] Figure 5 A schematic diagram of the second transistor conduction circuit structure of a driving method for improving the reliability of a power semiconductor gate provided by a certain embodiment of the present invention;

[0057] Figure 6 A schematic diagram of a simulation experiment circuit structure of a driving method for improving the reliability of a power semiconductor gate provided by a certain embodiment of the present invention;

[0058] Figure 7 Schematic diagram of experimental results of the fluctuation weakening effect of a driving method for improving the reliability of a power semiconductor gate provided by a certain embodiment of the present invention Figure 1 ;

[0059] Figure 8 Schematic diagram of experimental results of the fluctuation weakening effect of a driving method for improving the reliability of a power semiconductor gate provided by a certain embodiment of the present invention Figure 2 ;

[0060] Fig. 9 Schematic diagram of experimental results of the effect of a driving method for improving the reliability of a power semiconductor gate on the operating speed of a switch tube provided by a certain embodiment of the present invention Figure 1 ;

[0061] Fig.10 Schematic diagram of experimental results of the effect of a driving method for improving the reliability of a power semiconductor gate on the operating speed of a switch tube provided by a certain embodiment of the present invention Figure 2 ;

[0062] Fig.11 A schematic diagram of a module structure of a driving system for improving the reliability of a power semiconductor gate provided by a certain embodiment of the present invention;

[0063] Fig.12 A schematic diagram of the structure of a first control module of a drive system for improving the reliability of a power semiconductor gate provided by a certain embodiment of the present invention;

[0064] Fig.13 A schematic diagram of the structure of a second control module of a drive system for improving the reliability of a power semiconductor gate provided in one embodiment of the present invention.

[0065] Reference numerals: Q1 second transistor, Q2 first transistor, Sc energy storage capacitor, a first terminal, b second terminal, c third terminal, d fourth terminal, D drain, G gate, S source, R g Protection resistor, Lg Parasitic inductance, u gs is the voltage at point a, u drv is the voltage at point b, Turn on in the figure specifically means that the upper switch tube is turned on, Off state in the figure specifically means that the lower switch tube remains in the off state, Using original driver: This waveform is the driving voltage waveform after using the original driving circuit, without improvement measures, Using proposed driver: This waveform is the driving voltage waveform after using the circuit proposed in this patent, Q1: u gs , represents the driving voltage waveform of the second switch tube Q1 in the double pulse experiment, Q2: u gs , represents the driving voltage waveform of the first lower switch tube Q2 in the double pulse experiment. DETAILED DESCRIPTION

[0066] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0067] Example 1

[0068] See also Figure 2 , Figure 2 A schematic diagram of a driving circuit module structure of a driving method for improving the reliability of a power semiconductor gate provided by a certain embodiment of the present invention. Figure 2 As shown, an embodiment of the present invention provides a driving circuit for a driving method for improving the reliability of a power semiconductor gate, comprising: a first transistor 201, a second transistor 202, an energy storage capacitor 203, a power semiconductor circuit 204 and an external circuit 205;

[0069] The source of the first transistor 201 and the source of the second transistor 202 are electrically connected to form a first terminal, the first terminal of the power semiconductor circuit 204 is electrically connected to the first terminal, the gate of the first transistor 201 is electrically connected to the first terminal of the external circuit 205 as the second terminal, the gate of the second transistor 202 is electrically connected to the second terminal of the external circuit 205 as the third terminal, the drain of the first transistor 201 and the drain of the second transistor 202 are electrically connected to form a fourth terminal, the first terminal of the energy storage capacitor 203 is electrically connected to the fourth terminal, the third terminal of the external circuit 205 is electrically connected to the second terminal of the energy storage capacitor 203, the second terminal of the power semiconductor circuit 204 is electrically connected to the first terminal of the external circuit 205, and the third terminal of the power semiconductor circuit 204 is electrically connected to the second terminal of the external circuit 205;

[0070] As an example of this embodiment, the power semiconductor circuit 204 includes: a first switch tube 206 and a second switch tube 207;

[0071] The gate of the first switch tube 206 is electrically connected to the first end of the power semiconductor circuit 204, the drain of the first switch tube 206 is electrically connected to the source of the second switch tube 207, the source of the first switch tube 206 is electrically connected to the third end of the power semiconductor circuit 204, and the gate of the second switch tube 207 is electrically connected to the second end of the power semiconductor circuit 204; based on the pulse signal provided by the external circuit 205, the conduction and shutdown of the first switch tube 206 and the second switch tube 207 of the power semiconductor circuit 204 are controlled.

[0072] As an example of this embodiment, the external circuit 205 includes: a driving chip 208 and a suppression circuit 209; the suppression circuit 209 includes a protection resistor 211 and a parasitic inductor 210;

[0073] The driver chip 208 is electrically connected to the second endpoint, the third endpoint and the fourth endpoint respectively; the first end of the protection resistor 211 is electrically connected to the second endpoint and the driver chip 208 respectively, the second end of the protection resistor 211 is electrically connected to the first end of the parasitic inductance 210, and the second end of the parasitic inductance 210 is electrically connected to the first endpoint; the front stage of the driver chip 208 is used to provide digital signals and digital power supply; the rear stage of the driver chip 208 is used to provide driving three-level power supply; the parasitic inductance 210 is used to suppress current; and the protection resistor 211 is used to protect the circuit.

[0074] A schematic diagram of a driving circuit module structure based on the above-mentioned driving method for improving the reliability of a power semiconductor gate is shown in FIG. Figure 1 , construct as Figure 1The driving circuit of a driving method for improving the gate reliability of a power semiconductor shown in the figure is explained in more detail; the first part (Part1) is a newly added driving circuit for improving the gate reliability based on energy storage capacitors, which consists of a PNP transistor (T1, equivalent to the first transistor), an NPN transistor (T2, equivalent to the second transistor) and an energy storage capacitor (Sc), which can provide a fast discharge path and Miller energy storage area for the fluctuating excitation source (Miller current); the second part (Part2) is the digital signal and digital power supply of the front stage of the driver chip; the third part (Part3) is the three-level power supply of the rear stage driver chip; Q1 is the second switch tube, Q2 is the first switch tube, R g For protection resistance, L g Parasitic inductance refers to the parasitic parameters introduced into the circuit by the driving circuit due to factors such as manufacturing.

[0075] A specific explanation is Figure 1 In the figure, T1 and T2 are regarded as two interference suppression channels in opposite directions, respectively targeting the gate-source voltage u gs There are two situations: higher than -4V and lower than -4V; when u gs When point a (equivalent to the first endpoint) rises to -5V, due to the parasitic parameter L g The existence of drv Rising slower than u gs ,u drv (point b, equivalent to the second endpoint) still stays at -4V, at this time the first transistor T1 reaches the conduction condition, the triode is turned on, at this time the Miller current passes through T1 to store energy in the energy storage capacitor Sc, point d is equivalent to the fourth endpoint; on the contrary, when u gs When (point a) is lower than -5V, the voltage at point c (equivalent to the third endpoint) is maintained at -4V, and T2 reaches the conduction condition. At this time, the energy stored in the capacitor is supplemented by T2. gs missing.

[0076] As an example of this embodiment, see Figure 3 , Figure 3 A schematic flow chart of a driving method for improving the reliability of a power semiconductor gate provided by an embodiment of the present invention; Figure 3 As shown, a driving method for improving the reliability of a power semiconductor gate proposed in an embodiment of the present invention includes steps 301 to 304, each of which is specifically as follows:

[0077] Step 301, obtaining an excitation current based on an external circuit;

[0078] As an example of this embodiment, based on the fluctuation signal generated by the driver chip of the external circuit, the first switch tube and the second switch tube are controlled to be turned on and off; based on the turn-on and turn-off of the first switch tube and the second switch tube, an excitation current is output through the gate of the first switch tube. Specifically, through the fluctuation signal provided by the external circuit, Q1 and Q2 will have a state change of on and off, and each state switch will generate a fluctuation excitation source (Miller current) that is injected into the driver circuit through the gate of the Q1 device.

[0079] Step 302, based on the second endpoint and the third endpoint, respectively generate a first conduction voltage and a second conduction voltage through the excitation current;

[0080] As an example of this embodiment, based on the driving chip of the external circuit, the second terminal voltage and the third terminal voltage are obtained respectively; the voltage difference between the second terminal voltage and the excitation current and the voltage difference between the third terminal voltage and the excitation current are calculated respectively to obtain the first conduction voltage and the second conduction voltage. For details, see Figure 4 and Figure 5 , Figure 4 A schematic diagram of a first transistor conduction circuit structure of a driving method for improving the reliability of a power semiconductor gate provided by a certain embodiment of the present invention; Figure 5 A schematic diagram of a second transistor conduction circuit structure of a driving method for improving the reliability of a power semiconductor gate provided by an embodiment of the present invention; Figure 4 and Figure 5 As shown in the figure, every time the gate of Q1 device injects the excitation current into the driving circuit, a voltage will be generated between points a and b of Q1. When the voltage reaches the conduction threshold voltage of T1 (1V), the Miller current discharge path is opened. At this time, the voltage across Q1 is the first conduction voltage; a voltage will also be generated between points a and c of Q2. When the voltage reaches the conduction threshold voltage of T2 (1V), u gs The complementary path is opened, and the voltage across Q2 is the second on-state voltage. It is worth mentioning that Turn on in the figure means that the upper switch tube is turned on; Offstate in the figure means that the lower switch tube remains in the off state.

[0081] Step 303: If the first on-voltage satisfies the on-threshold voltage of the first transistor, the first transistor is controlled to be turned on and the excitation current is transmitted to the energy storage capacitor for storage, so as to control the voltage at the first end of the power semiconductor circuit to decrease;

[0082] As an example of this embodiment, when the first on-voltage is greater than or equal to the on-threshold voltage of the first transistor, the first transistor is controlled to be on and the second transistor is controlled to be off; the excitation current is transmitted to the energy storage capacitor through the first transistor so that the energy of the excitation current is stored in the energy storage capacitor; by storing the energy of the excitation current in the energy storage capacitor, the voltage at the first end of the power semiconductor circuit is reduced. For details, see Figure 4 , Figure 4 A schematic diagram of a first transistor conduction circuit structure of a driving method for improving the reliability of a power semiconductor gate provided by a certain embodiment of the present invention; Figure 4 As shown, the fluctuation will be superimposed on -4V, resulting in a gate-source voltage u gs When the ripple excitation source (Miller current) is injected into the driver circuit through the device gate, the parasitic inductance L g With current suppression function, u gs will precede u drv Rising, based on the first on-voltage, T1 is turned on, and the current gain effect of the transistor can quickly discharge the Miller current to the capacitor Sc for energy storage. The above mechanism can be used to reduce the rising fluctuation in a positive direction.

[0083] Step 304: If the second on-voltage satisfies the on-threshold voltage of the second transistor, the second transistor is controlled to be on and the energy stored in the energy storage capacitor is transferred to the first terminal to supplement the excitation current so as to control the voltage at the first terminal of the power semiconductor circuit to increase.

[0084] As an example of this embodiment, when the second on-voltage is greater than or equal to the on-threshold voltage of the second transistor, the second transistor is controlled to be on and the first transistor is turned off; the energy stored in the energy storage capacitor is transmitted to the first terminal through the second transistor, so that the energy of the excitation current is supplemented to the first terminal voltage of the power semiconductor circuit; the first terminal voltage of the power semiconductor circuit is increased by supplementing the energy of the excitation current to the first terminal voltage of the power semiconductor circuit. For details, see Figure 5 , Figure 5 A schematic diagram of a second transistor conduction circuit structure of a driving method for improving the reliability of a power semiconductor gate provided by an embodiment of the present invention; Figure 5 As shown, the voltage at point a will fluctuate in the reverse direction to below -4V, and the voltage at point c will stabilize at -4V. Based on the second on-state voltage, Q2 is turned on, and the current gain effect of the transistor can quickly transfer the energy stored in capacitor Sc to point a to supplement ugs. At this time, the voltage gap will be quickly filled. The above working mechanism can reduce the drop fluctuation in the reverse direction.

[0085] An embodiment of the present invention proposes a driving method for improving the reliability of a power semiconductor gate. By adding a simple circuit consisting of a first transistor, a second transistor and an energy storage capacitor, two different on-state voltages are generated based on an excitation current obtained from an external circuit. The on and off of the first transistor and the second transistor are controlled according to the on-state voltage. When the first transistor is turned on, the energy generated by the excitation current is stored in the energy storage capacitor, so that the rising fluctuation of the voltage at the first end of the power semiconductor circuit is positively reduced. When the second transistor is turned on, the energy stored in the energy storage capacitor is transmitted to the first end to supplement the excitation current, so that the falling fluctuation of the voltage at the first end of the power semiconductor circuit is reversely reduced. By weakening the voltage fluctuation of the voltage at the first end of the power semiconductor circuit, the probability of erroneous conduction of the switch tube is effectively reduced, thereby improving the gate reliability of the power device.

[0086] Example 2

[0087] See also Figure 6 , Figure 6 A schematic diagram of a simulation experiment circuit structure of a driving method for improving the reliability of a power semiconductor gate provided by a certain embodiment of the present invention; Figure 6 As shown, in order to verify that the driving method for improving the reliability of a power semiconductor gate proposed in the present invention can achieve the effect of improving the reliability of the power semiconductor gate, an LTspice simulation experiment is designed for verification. In the simulation experiment of this embodiment, the parameters of each component are shown in Table 1:

[0088] Table 1 Device parameters and notes

[0089] symbol Remark symbol Remark Driver Chip ADUM4146B L 0.7mH Ron 6.2Ω Q1 CAB011M12FM3 Roff 1.5Ω Q2 CAB011M12FM3 LG 0.1μH Sc 100μF T1 PNP T2 NPN

[0090] In the table, Driver chip is the driver chip used, which converts the control signal output by the industrial control chip into a driving voltage signal received by the gate of the power device; L is the inductor, which serves as the main power inductor in the double pulse experiment. The current condition of the double pulse experiment can be modified by changing the conduction time length and the inductance value; R on R is the resistance of the driving current channel in the driving circuit; off L is the resistance of the drive current channel in the drive circuit during shutdown. g is the parasitic inductance, which represents the parasitic parameter introduced into the circuit by the driving circuit due to factors such as manufacturing; Q1 and Q2 represent the main power semiconductor devices, which are the research objects; Sc is the capacitor that stores the energy of interference fluctuations; T1 and T2 are transistors, which are used to construct the path for energy transfer of interference fluctuations.

[0091] The specific steps of the simulation experiment are as follows:

[0092] (1) The upper switch tube performs two pulse conduction actions, each pulse lasts 15 μs, and the lower switch tube remains off. The fluctuation waveform is recorded to verify the fluctuation weakening effect of the proposed scheme.

[0093] (2) Record the gate-source voltage waveform when the switch tube switches state to verify the impact of the proposed scheme on the device switching speed.

[0094] The results and analysis of the simulation experiment are as follows:

[0095] See also Figure 7 , Figure 8 , Fig. 9 and Fig.10 , Figure 7 Schematic diagram of experimental results of the fluctuation weakening effect of a driving method for improving the reliability of a power semiconductor gate provided by a certain embodiment of the present invention Figure 1 ; Figure 8 Schematic diagram of experimental results of the fluctuation weakening effect of a driving method for improving the reliability of a power semiconductor gate provided by a certain embodiment of the present invention Figure 2 ; Fig. 9 Schematic diagram of experimental results of the effect of a driving method for improving the reliability of a power semiconductor gate on the operating speed of a switch tube provided by a certain embodiment of the present invention Figure 1 ; Fig.10 Schematic diagram of experimental results of the effect of a driving method for improving the reliability of a power semiconductor gate on the operating speed of a switch tube provided by a certain embodiment of the present invention Figure 2 ;like Figure 7 , Figure 8 , Fig. 9 and Fig.10 As shown in the figure, L:I represents the value of the current in the main power inductor in the double pulse experiment; Q1:u gs Represents the driving voltage waveform of the second switch Q1 in the double pulse experiment; Q2: u gs Represents the driving voltage waveform of the first lower switch Q2 in the double pulse experiment; Using original driver: This waveform is the driving voltage waveform after using the original driving circuit, without any improvement measures; Using proposed driver: This waveform is the driving voltage waveform after using the circuit proposed in this patent;

[0096] The experimental results are analyzed as follows: (1) Fluctuation weakening effect The fluctuation weakening effect is as follows: Figure 7 and Figure 8 As shown in the figure, the fluctuation is reproduced under the conditions of DC voltage reaching 700V and current reaching 15A. If no optimization measures are applied to the drive circuit ( Figure 7), the gate and source voltage fluctuation range caused by interference can reach 6.291V. This degree of fluctuation cannot be ignored compared with the -4V turn-off voltage, and it is very easy to cause the wrong turn-on of the light-opening tube; however, after adopting the proposed solution ( Figure 8 ), the fluctuation range is narrowed to about 2.528V. The above simulation results show that this scheme has a good weakening effect on the gate-source voltage fluctuation, which can effectively reduce the probability of erroneous conduction of the switch tube and then improve the gate reliability of the power device.

[0097] (2) Impact on the switching speed of the switch: The gate-source voltage of the state switching without additional drive circuit and using this scheme is as follows Fig. 9 and Fig.10 As shown, when the proposed solution is adopted, the waveform changes of the gate-source voltage presented by the two are almost the same during the process of the device switching from the off state to the on state. This shows that the on-speed of the device is almost unaffected. At the same time, it is worth noting that during the process of the device switching from the on state to the off state, the present invention can accelerate the off action. A higher off speed means that a smaller dead time can be used, thereby reducing the waveform distortion rate of the output voltage and current. This characteristic makes the circuit have a higher application value.

[0098] An embodiment of the present invention proposes a driving method for improving the reliability of a power semiconductor gate. From the results of experimental simulation, it can be seen that the present invention does not need to reduce the switching frequency of the converter and has high versatility. It can be added to an existing mature circuit without changing the fixed design, and the design time cost is low. In addition, the present invention does not need to use an additional control circuit, which reduces the difficulty of implementation. Under the above premise, the gate reliability of the power device is effectively improved, so that the power device can maintain the on and off states more stably, avoiding short-circuit failures caused by incorrect conduction of the power device.

[0099] Example 3

[0100] See also Fig.11 , Fig.11 A schematic diagram of a module structure of a driving system for improving the reliability of a power semiconductor gate provided by a certain embodiment of the present invention; Fig.11 As shown, an embodiment of the present invention provides a driving system for improving the reliability of a power semiconductor gate, comprising:

[0101] Excitation current acquisition module 1101, conduction voltage generation module 1102, first control module 1103 and second control module 1104;

[0102] The excitation current acquisition module 1101 is used to acquire the excitation current based on the external circuit;

[0103] The on-state voltage generating module 1102 is used to generate a first on-state voltage and a second on-state voltage respectively through the excitation current based on the second endpoint and the third endpoint;

[0104] The first control module 1103 is used to control the first transistor to turn on and transmit the excitation current to the energy storage capacitor for storage if the first turn-on voltage meets the turn-on threshold voltage of the first transistor, so as to control the voltage at the first end of the power semiconductor circuit to decrease;

[0105] As an example of this embodiment, see Fig.12 , Fig.12 A schematic diagram of the structure of a first control module of a drive system for improving the reliability of a power semiconductor gate provided by a certain embodiment of the present invention; Fig.12 The first control module 1103 is used to control the first transistor to turn on and transmit the excitation current to the energy storage capacitor for storage if the first turn-on voltage meets the turn-on threshold voltage of the first transistor, so as to control the voltage at the first end of the power semiconductor circuit to decrease, and also includes:

[0106] A first threshold determination unit 1201, an energy storage unit 1202 and a first voltage control unit 1203;

[0107] The threshold judgment unit 1201 is used to control the first transistor to be turned on and the second transistor to be turned off when the first turn-on voltage is greater than or equal to the turn-on threshold voltage of the first transistor;

[0108] The energy storage unit 1202 is used to transmit the excitation current to the energy storage capacitor through the first transistor, so that the energy of the excitation current is stored in the energy storage capacitor;

[0109] The first voltage control unit 1203 is used to store the energy of the excitation current in the energy storage capacitor so as to reduce the voltage at the first terminal of the power semiconductor circuit.

[0110] The second control module 1104 is used to control the second transistor to turn on and transfer the energy stored in the energy storage capacitor to the first terminal if the second turn-on voltage meets the turn-on threshold voltage of the second transistor, so as to supplement the excitation current and control the voltage at the first terminal of the power semiconductor circuit to increase.

[0111] As an example of this embodiment, see Fig.13 , Fig.13 A schematic diagram of the structure of a second control module of a drive system for improving the reliability of a power semiconductor gate provided by a certain embodiment of the present invention. Fig.13The second control module 1104 is used to control the second transistor to turn on and transfer the energy stored in the energy storage capacitor to the first terminal if the second turn-on voltage meets the turn-on threshold voltage of the second transistor, and supplement the excitation current to control the voltage of the first terminal of the power semiconductor circuit to increase, and also includes:

[0112] A second threshold determination unit 1301, an energy supplement unit 1302, and a second voltage control unit 1303;

[0113] The second threshold judgment unit 1301 is used to control the second transistor to be turned on and the first transistor to be turned off when the second turn-on voltage is greater than or equal to the turn-on threshold voltage of the second transistor;

[0114] The energy supplement unit 1302 is used to transmit the energy stored in the energy storage capacitor to the first terminal through the second transistor, so that the energy of the excitation current is supplemented to the first terminal voltage of the power semiconductor circuit;

[0115] The second voltage control unit 1303 is used for increasing the voltage at the first terminal of the power semiconductor circuit by adding energy of the excitation current to the voltage at the first terminal of the power semiconductor circuit.

[0116] An embodiment of the present invention proposes a driving system for improving the reliability of a power semiconductor gate. Two different on-voltages are generated based on an excitation current obtained from an external circuit by an excitation current acquisition module and an on-voltage generation module. The on and off of a first transistor and a second transistor are controlled according to the on-voltages. When the first transistor is turned on, the energy generated by the excitation current is stored in an energy storage capacitor through a first control module, so that the rising fluctuation of the voltage at the first end of the power semiconductor circuit is positively reduced. When the second transistor is turned on, the energy stored in the energy storage capacitor is transmitted to the first end of the excitation current through a second control module to supplement the excitation current, so that the falling fluctuation of the voltage at the first end of the power semiconductor circuit is reversely reduced. By weakening the voltage fluctuation of the voltage at the first end of the power semiconductor circuit, the probability of erroneous conduction of the switch tube is effectively reduced, thereby improving the gate reliability of the power device.

[0117] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

[0118] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples, unless they are contradictory.

[0119] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

Claims

1. A driving method for improving the reliability of a power semiconductor gate, characterized in that: A driving circuit for improving gate reliability, comprising: a first transistor, a second transistor, an energy storage capacitor, a power semiconductor circuit and an external circuit; The source of the first transistor and the source of the second transistor are electrically connected to form a first endpoint, the first end of the power semiconductor circuit is electrically connected to the first endpoint, the gate of the first transistor is electrically connected to the first end of the external circuit as the second endpoint, the gate of the second transistor is electrically connected to the second end of the external circuit as the third endpoint, the drain of the first transistor and the drain of the second transistor are electrically connected to form a fourth endpoint, the first end of the energy storage capacitor is electrically connected to the fourth endpoint, the third end of the external circuit is electrically connected to the second end of the energy storage capacitor, the second end of the power semiconductor circuit is electrically connected to the first end of the external circuit, and the third end of the power semiconductor circuit is electrically connected to the second end of the external circuit; The driving method for improving the reliability of a power semiconductor gate comprises: Based on the external circuit, obtain the excitation current; Based on the second terminal and the third terminal, respectively generate a first conduction voltage and a second conduction voltage through the excitation current; If the first on-voltage satisfies the on-threshold voltage of the first transistor, controlling the first transistor to be on and transmitting the excitation current to the energy storage capacitor for storage, so as to control the voltage at the first end of the power semiconductor circuit to decrease; If the second on-voltage satisfies the on-threshold voltage of the second transistor, the second transistor is controlled to be on and the energy stored in the energy storage capacitor is transferred to the first terminal to supplement the excitation current so as to control the voltage at the first terminal of the power semiconductor circuit to increase.

2. A driving method for improving the reliability of a power semiconductor gate as claimed in claim 1, characterized in that: The power semiconductor circuit comprises: a first switch tube and a second switch tube; The gate of the first switch tube is electrically connected to the first end of the power semiconductor circuit, the drain of the first switch tube is electrically connected to the source of the second switch tube, the source of the first switch tube is electrically connected to the third end of the power semiconductor circuit, and the gate of the second switch tube is electrically connected to the second end of the power semiconductor circuit; Based on the pulse signal provided by the external circuit, the first switch tube and the second switch tube of the power semiconductor circuit are controlled to be turned on and off.

3. A driving method for improving the reliability of a power semiconductor gate as claimed in claim 1, characterized in that: The external circuit includes: a driving chip and a suppression circuit; the suppression circuit includes a protection resistor and a parasitic inductor; The driving chip is electrically connected to the second endpoint, the third endpoint and the fourth endpoint respectively; the first end of the protection resistor is electrically connected to the second endpoint and the driving chip respectively, the second end of the protection resistor is electrically connected to the first end of the parasitic inductance, and the second end of the parasitic inductance is electrically connected to the first endpoint; The front stage of the driver chip is used to provide digital signals and digital power supply; The rear stage of the driver chip is used to provide a three-level driving power supply; The parasitic inductance is used to suppress current; The protection resistor is used to protect the circuit.

4. A driving method for improving the reliability of a power semiconductor gate as claimed in claim 3, characterized in that: The step of obtaining the excitation current based on the external circuit includes: Based on the fluctuation signal generated by the driving chip of the external circuit, the first switch tube and the second switch tube are controlled to be turned on and off; Based on the turning on and off of the first switch tube and the second switch tube, an excitation current is output through the gate of the first switch tube.

5. A driving method for improving the reliability of a power semiconductor gate as claimed in claim 4, characterized in that: The method of generating a first conduction voltage and a second conduction voltage respectively based on the second endpoint and the third endpoint through the excitation current comprises: Based on the driving chip of the external circuit, the second terminal voltage and the third terminal voltage are respectively obtained; The voltage difference between the second terminal voltage and the excitation current and the voltage difference between the third terminal voltage and the excitation current are calculated respectively to obtain a first conduction voltage and a second conduction voltage.

6. A driving method for improving the reliability of a power semiconductor gate as claimed in claim 5, characterized in that: If the first on-voltage satisfies the on-threshold voltage of the first transistor, controlling the first transistor to be on and transmitting the excitation current to the energy storage capacitor for storage, so as to control the voltage at the first end of the power semiconductor circuit to decrease, comprises: When the first on-voltage is greater than or equal to the on-threshold voltage of the first transistor, the first transistor is controlled to be on and the second transistor is controlled to be off; transmitting the excitation current to the energy storage capacitor through the first transistor so that the energy of the excitation current is stored in the energy storage capacitor; The energy of the excitation current is stored in the energy storage capacitor, so that the voltage at the first terminal of the power semiconductor circuit is reduced.

7. A driving method for improving the reliability of a power semiconductor gate as claimed in claim 6, characterized in that: If the second on-voltage satisfies the on-threshold voltage of the second transistor, the second transistor is controlled to be on and the energy stored in the energy storage capacitor is transferred to the first terminal, the excitation current is supplemented to control the voltage of the first terminal of the power semiconductor circuit to increase, including: When the second on-voltage is greater than or equal to the on-threshold voltage of the second transistor, the second transistor is controlled to be on and the first transistor is controlled to be off; The energy stored in the energy storage capacitor is transmitted to the first terminal through the second transistor, so that the energy of the excitation current is supplemented to the first terminal voltage of the power semiconductor circuit; The energy of the excitation current is supplemented to the first terminal voltage of the power semiconductor circuit, so that the first terminal voltage of the power semiconductor circuit is increased.

8. A driving system for improving the reliability of a power semiconductor gate, executing a driving method for improving the reliability of a power semiconductor gate as claimed in any one of claims 1 to 7, characterized in that: include: An excitation current acquisition module, a conduction voltage generation module, a first control module and a second control module; The excitation current acquisition module is used to acquire the excitation current based on the external circuit; The conduction voltage generating module is used to generate a first conduction voltage and a second conduction voltage respectively through the excitation current based on the second endpoint and the third endpoint; The first control module is used for controlling the first transistor to turn on and transmit the excitation current to the energy storage capacitor for storage if the first turn-on voltage meets the turn-on threshold voltage of the first transistor, so as to control the voltage at the first end of the power semiconductor circuit to decrease; The second control module is used to control the second transistor to turn on and transfer the energy stored in the energy storage capacitor to the first terminal if the second turn-on voltage meets the turn-on threshold voltage of the second transistor, so as to supplement the excitation current and control the voltage at the first terminal of the power semiconductor circuit to increase.

9. A driving system for improving the reliability of a power semiconductor gate as claimed in claim 8, characterized in that: The first control module is used to control the first transistor to turn on and transmit the excitation current to the energy storage capacitor for storage if the first turn-on voltage meets the turn-on threshold voltage of the first transistor, so as to control the voltage at the first end of the power semiconductor circuit to decrease, and also includes: A first threshold determination unit, an energy storage unit and a first voltage control unit; The threshold judgment unit is used for controlling the first transistor to be turned on and the second transistor to be turned off when the first turn-on voltage is greater than or equal to the turn-on threshold voltage of the first transistor; The energy storage unit is used to transmit the excitation current to the energy storage capacitor through the first transistor, so that the energy of the excitation current is stored in the energy storage capacitor; The first voltage control unit is used for reducing the voltage at the first terminal of the power semiconductor circuit by storing the energy of the excitation current in the energy storage capacitor.

10. A driving system for improving the reliability of a power semiconductor gate as claimed in claim 9, characterized in that: The second control module is used to control the second transistor to turn on and transfer the energy stored in the energy storage capacitor to the first terminal if the second turn-on voltage meets the turn-on threshold voltage of the second transistor, and supplement the excitation current to control the voltage of the first terminal of the power semiconductor circuit to increase, and also includes: a second threshold determination unit, an energy replenishment unit, and a second voltage control unit; The second threshold judgment unit is used to control the second transistor to be turned on and the first transistor to be turned off when the second turn-on voltage is greater than or equal to the turn-on threshold voltage of the second transistor; The energy supplement unit is used to transmit the energy stored in the energy storage capacitor to the first terminal through the second transistor, so that the energy of the excitation current is supplemented to the first terminal voltage of the power semiconductor circuit; The second voltage control unit is used for increasing the voltage at the first terminal of the power semiconductor circuit by supplementing the energy of the excitation current to the voltage at the first terminal of the power semiconductor circuit.

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