Bimodal driving method and driving circuit of IGBT (Insulated Gate Bipolar Translator)

Abstract

The invention discloses a bimodal driving method and driving circuit of an IGBT (Insulated Gate Bipolar Translator), and relates to the technical field of power device control. When the IGBT is switched from the rated working condition to the IGBT overload working condition, the IGBT is switched on / off through the higher driving voltage and the switch-on resistance / switch-off resistance, the driving parameters are dynamically switched between the rated working condition and the overload working condition, decoupling of the rated working condition and the overload working condition is achieved, and the reliability of the IGBT is improved. Under a rated condition, a driving parameter of a normal-scale state is adopted to ensure operation efficiency, a driving parameter of an overload mode is actively switched during overload, grid oscillation and collector-emitter overvoltage in a switching transient process are suppressed, on-state loss is reduced, and current performance and operation reliability of the IGBT under an instantaneous overload condition are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of power device control technology, and in particular to a dual-mode driving method and driving circuit for IGBTs. Background Technology

[0002] Currently, with the rapid development of "high-energy-consuming and high-polluting" power systems, new energy sources, represented by wind power and photovoltaics, are being connected to the grid on a large scale via power electronic converters. This leads to a decrease in system inertia and a weakening of system strength, posing a severe challenge to stable operation. Against this backdrop, power electronic converters, possessing functions such as fault ride-through and voltage and frequency support, place extremely high demands on the short-time overcurrent capability of the core component of the converter—the Insulated Gate Bipolar Transistor (IGBT).

[0003] Taking the typical operation of an IGBT full-bridge submodule employing carrier phase-shift modulation in a converter under high overload conditions as an example, the reliability of the devices in the submodule is severely threatened when the bridge arm current level increases under overload conditions. This manifests in two ways: First, in the on-state, the IGBT collector current increases and the on-state voltage drop rises, leading to a sharp increase in on-state losses and a severe lack of overload thermal margin. Second, during the switching process, the extremely high rates of change of current (di / dt) and voltage (dv / dt) cause severe oscillations, resulting in the gate voltage exceeding the upper limit specified in the datasheet. V GES During the turn-off process, the collector-emitter voltage spike exceeds the safety limit. V CES These problems seriously affect the reliability of IGBTs under overload conditions.

[0004] To address high overload demands, the prevailing approach in engineering and academia is to focus on system-level thermal management strategies, with reducing switching frequency being the most typical and widely adopted method. This method reduces switching losses by decreasing the number of switching operations, thereby providing a limited thermal margin to accommodate increased on-state current.

[0005] However, the "frequency reduction overload" strategy has limited effectiveness in addressing the problem of drastically increased conduction losses caused by overload current. In high-voltage, high-capacity converters, conduction losses are dominant, and relying solely on frequency reduction to improve overload capacity has significant limitations. Furthermore, this method cannot effectively suppress gate oscillations and collector-emitter overvoltages caused by extremely high di / dt and dv / dt during switching transients, leaving the device still at risk of overvoltage breakdown and gate failure. Summary of the Invention

[0006] Therefore, it is necessary to provide a dual-mode driving method and driving circuit for IGBTs to address the aforementioned technical problems.

[0007] The present invention adopts the following technical solution: This invention provides a dual-mode driving method for IGBTs. Under rated operating conditions, the IGBT is turned on based on a first positive voltage and a first turn-on resistor, or turned off based on a first negative voltage and a first turn-off resistor. Under IGBT overload conditions, the IGBT is turned on based on a second positive voltage and a second turn-on resistor, or turned off based on a second negative voltage and a second turn-off resistor. The second positive voltage is greater than the first positive voltage, and the second turn-on resistor is greater than the first turn-on resistor; the second negative voltage is greater than or equal to the first negative voltage, and the second turn-off resistor is greater than the first turn-off resistor.

[0008] This invention provides a driving circuit for an IGBT, comprising: First positive voltage terminal, first negative voltage terminal, second positive voltage terminal, second negative voltage terminal, first switch, second switch, third switch, fourth switch, first turn-on resistor, first turn-off resistor, second turn-on resistor, second turn-off resistor, four input terminals and one output terminal; the output terminal is connected to the gate of the IGBT; The first positive voltage is connected to the output terminal via the first switch and the first turn-on resistor in sequence, and the first input terminal is connected to the first switch; when the first control command is received, the first input terminal is at a high level, the other input terminals are at a low level, the first switch is turned on, and the IGBT is turned on based on the first positive voltage and the first turn-on resistor; The first negative voltage is connected to the output terminal via the second switch and the first turn-off resistor in sequence, and the second input terminal is connected to the second switch; when the second control command is received, the second input terminal is at a high level, the other input terminals are at a low level, the second switch is turned on, and the IGBT is turned off based on the first negative voltage and the first turn-off resistor; The second positive voltage is connected to the output terminal via the third switch and the first turn-on resistor in sequence, and the third input terminal is connected to the third switch; when the third control command is received, the third input terminal is at a high level, the other input terminals are at a low level, the third switch is turned on, and the IGBT is turned on based on the second positive voltage and the second turn-on resistor. The second negative voltage is connected to the output terminal via the fourth switch and the first turn-on resistor in sequence. The fourth input terminal is connected to the fourth switch. When the fourth control command is received, the fourth input terminal is at a high level, the other input terminals are at a low level, the fourth switch is turned on, and the IGBT is turned off based on the second negative voltage and the second turn-off resistor. Wherein, the second positive voltage is greater than the first positive voltage, and the second turn-on resistor is greater than the first turn-on resistor; the second negative voltage is greater than or equal to the first negative voltage, and the second turn-off resistor is greater than the first turn-off resistor.

[0009] The present invention provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described dual-mode driving method for IGBTs.

[0010] The present invention provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the above-described dual-mode driving method for IGBTs.

[0011] The above-mentioned at least one technical solution adopted in this invention can achieve the following beneficial effects: This invention enables the IGBT to switch on / off via a higher drive voltage and turn-on / turn-off resistor when switching from rated operating condition to IGBT overload operating condition. By dynamically switching drive parameters between rated and overload operating conditions, the invention achieves decoupling between the two conditions. Under rated operating conditions, constant-mode drive parameters are used to ensure operating efficiency. Under overload conditions, the drive parameters of the overload mode are actively switched to suppress gate oscillation and collector-emitter overvoltage during switching transients and reduce conduction losses, significantly improving the current performance and operational reliability of the IGBT under instantaneous overload conditions. Attached Figure Description

[0012] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings:

[0013] Figure 1 A schematic diagram illustrating the typical operation of an IGBT full-bridge submodule employing carrier phase-shift modulation in a converter under high overload conditions, as provided by the present invention. Figure 2 A schematic flowchart of a dual-mode driving method for an IGBT provided by the present invention; Figure 3 A schematic diagram of an IGBT dual-mode drive circuit provided by the present invention; Figure 4 This invention provides a comparative diagram of collector current, gate voltage, and collector-emitter voltage under overload conditions, comparing the constant mode and the overload mode under overload conditions. Figure 5 A schematic diagram of the cell structure of a trench gate IGBT provided by the present invention; Figure 6 A waveform diagram illustrating a typical IGBT turn-on and turn-off process provided by the present invention; Figure 7 This invention provides a schematic diagram of a driver board. Figure 8This invention provides a schematic diagram of the IGBT's off or on state. Figure 9 A schematic diagram of a dual-pulse experimental circuit provided by the present invention; Figure 10 A schematic diagram of the IGBT turn-on waveform for different turn-on resistances provided by the present invention; Figure 11 A schematic diagram of the IGBT turn-off waveform for different turn-off resistors provided by the present invention; Figure 12 This invention provides a schematic diagram of two IGBT full-bridge submodules used in a practical engineering SVG. Figure 13 This is a schematic diagram of an experimental result provided by the present invention. Detailed Implementation

[0014] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0015] Figure 1 This is a schematic diagram illustrating the typical operation of an IGBT full-bridge submodule employing carrier phase-shift modulation in a converter according to the present invention under high overload conditions. Figure 1 Part (a) is the full-bridge submodule. U C This refers to the capacitor voltage of the submodule. I arm This represents the converter bridge arm current. Figure 1 Part (b) shows in t set Once the overload condition is entered, the bridge arm current rises rapidly. The blue curve represents the rated condition, and the yellow curve represents the overload condition. Figure 1 Part (c) shows the operating waveforms of the IGBT in the submodule before and after overload. The yellow curves, from top to bottom, represent the collector current, collector-emitter voltage, and gate voltage under high overload conditions, while the blue curves, from top to bottom, represent the collector current, collector-emitter voltage, and gate voltage under rated conditions. I C For collector current, V CE This is the collector-emitter voltage. V CES This is the maximum rated value of the collector-emitter voltage. V GE Gate voltage,V GES This represents the maximum rated gate voltage. It is evident that under overload conditions, the increased bridge arm current level severely threatens the reliability of devices operating within the submodule.

[0016] Existing "frequency reduction overload" strategies still have limitations. Fundamentally, there is an essential conflict between the requirements of rated operation and overload operation on device performance: the former aims for high efficiency and low loss in long-term operation, and usually uses a smaller gate resistance to optimize switching losses; while the latter prioritizes safe ride-through of short-term faults, and in this case, it is necessary to appropriately increase the gate resistance to optimize switching electrical stress.

[0017] A fixed set of driving parameters always has its limitations, forcing system designers to adopt a conservative strategy of increasing device capacity. To address this, this invention proposes a dual-mode driving method: under rated operating conditions, conventional driving parameters are used for normal mode operation; under overload conditions, it actively switches to another set of driving parameters suitable for high overload conditions for overload mode operation. By switching between two independent driving modes, the rated and overload operating conditions are decoupled, significantly improving the current performance and operational reliability of IGBTs under instantaneous overload conditions.

[0018] The technical solutions provided by the various embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0019] Figure 2 This is a schematic diagram of a dual-mode driving method for IGBTs according to the present invention, which specifically includes the following steps: S101: Under the rated operating conditions of the IGBT, the IGBT is turned on based on the first positive voltage and the first turn-on resistor, or the IGBT is turned off based on the first negative voltage and the first turn-off resistor.

[0020] S102: Under IGBT overload conditions, the IGBT is turned on based on the second positive voltage and the second turn-on resistor, or the IGBT is turned off based on the second negative voltage and the second turn-off resistor.

[0021] Wherein, the second positive voltage is greater than the first positive voltage, and the second turn-on resistor is greater than the first turn-on resistor; the second negative voltage is greater than or equal to the first negative voltage, and the second turn-off resistor is greater than the first turn-off resistor.

[0022] This invention first explains the principle and operation mode of the dual-mode driving method. The core of the dual-mode driving method is to dynamically switch between two modes, normal and overload, according to the operating conditions: when the rated operation is running, the driving voltage and resistance parameters suitable for long-term operation are adopted; when an overload occurs, it automatically switches to a set of driving parameters with slightly higher voltage and slightly larger resistance to improve the instantaneous overcurrent capability and reliability of the device.

[0023] Figure 3 This is a schematic diagram of an IGBT dual-mode driving circuit in this invention. The blue and yellow parts correspond to the key circuits of the overload mode and the constant mode, respectively. The mode switching of the entire drive is implemented by the FPGA control chip.

[0024] Under rated operating conditions, the drive operates in a constant state. Based on the corresponding control commands issued by the FPGA control chip, when the IGBT device is turned on, S nl-on High level, other signals ( S nl-off , S ol-on , S ol-off When the voltage is low, the first positive voltage is applied. V nl-on With the first turn-on resistor R nl-on When shut down, S nl-off The voltage is high, and the rest are low. The first negative voltage is applied. V nl-off With the first turn-off resistor R nl-off .

[0025] When an overload condition occurs, the main controller sends an overload signal. S ol-set Based on the corresponding control commands issued by the FPGA control chip, the drive circuit actively switches to overload mode. When the IGBT device is turned on, S ol-on The voltage is high at all points, and low at the rest. A second positive voltage is applied. V ol-on With the second turn-on resistor R ol-on When shut down, S ol-off The voltage is high at one end and low at the other, then a second negative voltage is applied. V ol-off With the second turn-off resistor R ol-off .

[0026] Figure 4 This diagram illustrates a comparison of collector current, gate voltage, and collector-emitter voltage under overload conditions in this invention, comparing the conditions under normal operating conditions and those under overload conditions. It is evident that the method proposed in this invention effectively reduces the on-state voltage drop and losses of the IGBT by appropriately increasing the driving voltage, providing more thermal margin for overload operation. Simultaneously, by slightly increasing the driving resistance, it significantly suppresses current and voltage oscillations and overshoot during the switching process, ensuring the safe operation of the device under high overload conditions.

[0027] The following section provides a detailed explanation of the selection of driving voltage and turn-on / turn-off resistors. First, the mechanism of the influence of driving voltage on IGBT conduction loss and the selection method will be explained.

[0028] Figure 5 This is a schematic diagram of the cell structure of a trench gate IGBT according to the present invention. When the IGBT is turned on, its on-state voltage drop mainly includes the PN junction voltage drop. V PN The N-base region voltage drop, including the N-drift region and the N-buffer layer. V N Accumulation layer pressure drop V A Inversion layer channel pressure drop V T These four parts.

[0029] On-state pressure drop: (1).

[0030] like Figure 5 As shown, in the IGBT's on-state, from bottom to top, firstly, because conduction overcomes the heavy doping of P... + The built-in potential of the region and the N buffer layer, P + Voltage drop across the N junction: (2).

[0031] In the formula, k It is Boltzmann's constant. T Thermodynamic temperature q It is electron charge. p ( z p ) is P + Hole concentration at the boundary of the space charge layer. n ( z n ) is the electron concentration at the boundary of the space charge layer of the N-buffer layer. n i It is the concentration of intrinsic carriers.

[0032] Secondly, there is the voltage drop in the N-base region. Due to the large number of holes from the heavily doped P+ region entering the N-base region, the conductivity of the N-base region is greatly increased under the effect of conductivity modulation.

[0033] when Z N / Z a When the value is less than 1, the voltage drop in the N-base region is: (3).

[0034] when Z N / Za When the value is greater than 1, the voltage drop in the N-base region is: (4).

[0035] In the formula, Z N It is the depth of the N-base region. Z a It is the bipolar diffusion depth, where e is the natural base.

[0036] Next is the voltage drop of the accumulation layer. Because the positive gate voltage when the IGBT is turned on attracts electrons from the N-drift region, an accumulation layer forms next to the gate oxide layer. The voltage drop of the accumulation layer is: (5).

[0037] In the formula, J A It is the current density flowing through the accumulation layer. X cell It is the cell width. Z G It is the depth of the trench gate. Z P It is the depth of the P-base region. μ A It is the electron mobility of the accumulation layer. C ox It is the capacitance per unit area of ​​the gate oxide layer. V G It is the on-state gate voltage of the IGBT. V th It is the gate threshold voltage of the IGBT.

[0038] Finally, there's the inversion layer channel voltage drop. When the IGBT is turned on, the gate positive voltage is much higher than the MOS structure threshold voltage, creating a channel at the junction of the gate oxide layer and the P-base region, forming a strong inversion region. The voltage drop of the inversion layer channel is as follows: (6).

[0039] In the formula, J T It is the current density flowing through the inversion layer channel. Z ch It is the depth of the inversion layer channel. μ T It is the electron mobility of the inversion layer channel.

[0040] Power dissipation in the on-state when the IGBT is turned on: (7).

[0041] From equations (1) to (7), it can be seen that increasing the on-state gate voltage of the IGBT... V GIt can effectively reduce the voltage drop of the accumulation layer and the channel voltage drop of the inversion layer, thereby reducing the total on-state voltage drop and on-state power dissipation, and ultimately significantly reducing on-state losses. However, excessively high gate voltage will accelerate the aging of the gate oxide layer and even cause gate breakdown. Therefore, the selection of gate voltage needs to comprehensively weigh losses and reliability based on the operating conditions.

[0042] Under rated operating conditions, long-term reliability is the primary objective, and gate oxide aging is a key limiting factor. Therefore, the drive voltage under normal operating conditions should be reasonably selected while ensuring gate reliability. Under overload conditions, on the one hand, the main limiting factor for performance is heat accumulation, and appropriately increasing the gate voltage helps to reduce conduction losses and heat generation; on the other hand, since overload is a short-term transient process, the aging effect caused by increasing the gate voltage is negligible.

[0043] The mechanism of the influence of the driving resistor on the transient process of switching and the method of parameter selection. Figure 6 This is a waveform diagram illustrating a typical IGBT turn-on and turn-off process in this invention. Figure 6 middle, V on Positive gate drive voltage V mil The Miller plateau voltage, V off Negative gate drive voltage V peak To turn off peak voltage, V DC This refers to the capacitor voltage of the submodule. I peak To enable peak current, I load This is the load current.

[0044] 1. Mechanism and selection method of the influence of turn-on resistor on IGBT turn-on transient.

[0045] like Figure 6 As shown, in t 1~ t During the rapid current rise phase, the IGBT operates in the amplification region, and its collector current... I C It can be represented as: (8).

[0046] in, α It is the bipolar current gain of the IGBT. g m It is the transconductance of the channel in the IGBT gate MOS structure.

[0047] The IGBT turn-on process can be understood as driving a positive voltage input capacitor to the gate. C ies The charging process, therefore: (9).

[0048] in, I G This represents the gate current.

[0049] From equations (8) and (9), we can obtain: (10).

[0050] in, R on This is the turn-on resistor for gate drive.

[0051] The voltage drop during the IGBT turn-on phase can generally be understood as the drive passing through the gate to the Miller capacitance. C CG Reverse charging, therefore: (11).

[0052] For constant-mode operation, the selection of the turn-on resistor aims for high efficiency and low loss under rated conditions, and the recommended value from the datasheet is usually adopted directly. However, under overload conditions, transient reliability becomes the primary consideration.

[0053] like Figure 4 As shown, the current level increases significantly under overload. If a small turn-on resistor of constant mode is still used, it will lead to extremely high current and voltage change rates (di / dt and dv / dt), causing severe forced oscillations during the turn-on process and endangering device safety. From equations (10) and (11), it can be seen that with the increase in the gate drive turn-on resistor... R on As the current and voltage change rates decrease during the IGBT turn-on phase, the reduced current rise rate also decreases the reverse recovery rate of the complementary-side diode. Since the primary excitation source of forced oscillation is the drastic change in main circuit current and voltage, appropriately increasing the current in overload mode... R on This effectively suppresses oscillations by inhibiting the excitation amplitude, ensuring reliable turn-on process. Based on this, in one or more embodiments of the present invention, when determining the second turn-on resistor, the server aims to minimize turn-on losses and prevent oscillations during the IGBT overload process.

[0054] 2. Mechanism and selection method of the influence of the turn-off resistor on the IGBT turn-off transient.

[0055] like Figure 6 As shown, in t 3 ~ t 4 During the current-decreasing phase, the IGBT still operates in the amplification region, and the collector current also satisfies equation (8). Furthermore, during the turn-off phase, a negative driving voltage is applied to the gate input capacitor.C ies The discharge process also satisfies equation (9). Therefore, the rate of change of current during the turn-off phase can be derived similarly: (12).

[0056] in, R off This is the turn-off resistor for the gate drive.

[0057] During the voltage rise process in the turn-off phase, the capacitor CCG is positively charged through the turn-off resistor. The rate of change of the collector-emitter voltage at this time is: (13).

[0058] Because of the stray inductance in the circuit L stray The presence of leads to the generation of turn-off overvoltage spikes, which, combined with equation (12), yields: (14).

[0059] Similarly, under normal operating conditions, the turn-off resistor parameter can be selected based on the recommended value in the device's datasheet.

[0060] However, for the overload mode, by Figure 4 As shown, under overload conditions, forced oscillations occurred during the turn-off process; furthermore, the turn-off overvoltage spike exceeded the device's safe withstand voltage value specified in the datasheet. V CES From equations (12) to (14), it can be seen that as the turn-off resistor... R off With the increase of the voltage, current, and overvoltage spike during the IGBT turn-off phase all show a decreasing trend. Therefore, appropriately increasing the turn-off resistance under overload mode can limit voltage spikes within a safe range and also help suppress turn-off oscillations, improving the robustness of device operation. Based on this, in one or more embodiments of the present invention, the server can determine the second turn-off resistance with the goal of preventing oscillations during the turn-off process under IGBT overload conditions, ensuring that the collector-emitter voltage spike during turn-off is less than or equal to the safe limit, and minimizing turn-off losses.

[0061] based on Figure 2 The dual-mode driving method for IGBTs shown in this invention enables the IGBT to be turned on / off by using a higher driving voltage and turn-on / turn-off resistance when switching from rated operating condition to IGBT overload operating condition. By dynamically switching the driving parameters between rated and overload operating conditions, the rated and overload operating conditions are decoupled. Under rated operating conditions, constant mode driving parameters are used to ensure operating efficiency. Under overload conditions, the driving parameters of the overload mode are actively switched to suppress gate oscillation and collector-emitter overvoltage during switching transients and reduce conduction losses.

[0062] When applying the dual-mode driving method for IGBTs provided by this invention, it is not necessary to... Figure 1 The steps shown are executed in sequence. The specific execution order of each step can be determined as needed, and this invention does not impose any restrictions on it.

[0063] Furthermore, the present invention also provides embodiments of applying the method of the present invention: 1. Physical design of the driver board and verification of its active overload function.

[0064] Based on the above circuit principle, the hardware design of the driver board was completed, such as... Figure 7 As shown, Figure 7 This is a schematic diagram of a driver board according to the present invention. Overload signals are processed in real time via FPGA: when an overload command is received from the upper-level control, the system switches from normal mode to overload mode.

[0065] The double-pulse experiment verified the driving function, such as Figure 8 As shown, Figure 8 This is a schematic diagram illustrating the IGBT's off or on state in this invention. Figure 8 It is evident that the system can correctly switch modes regardless of whether an overload signal is sent in the IGBT off (different cycle) or on (same cycle) state, indicating that the designed driver has reliable active overload capability.

[0066] 2. Design of driving voltage and driving resistance parameters.

[0067] The FF300R17KE4 is a commonly used IGBT module in 10kV and 20kV voltage level converters in actual engineering. The parameter design of dual-mode drive in this section takes this device as an example.

[0068] For the standard driving voltage, refer to the driving voltage of this type of IGBT in actual engineering, and select a driving positive voltage of 15V and a driving negative voltage of -9V.

[0069] For overload mode driving voltage, increasing the positive driving voltage helps reduce the device's conduction losses. The maximum gate voltage specified in the IGBT datasheet is 20V. For IGBTs operating under high overload conditions, to minimize conduction losses and avoid issues such as gate oxide breakdown and aging, the positive driving voltage under overload mode can be appropriately increased. V ol-on The voltage is 20V. The negative driving voltage is to prevent mis-turn-on issues caused by interference when the device is off. Even under overload conditions, a -9V negative driving voltage is sufficient for a 1700V / 300A device; it should be consistent with the rated operating conditions.

[0070] For standard-state drive resistors, select the turn-on resistance parameter according to the recommended values ​​in the device datasheet.R nl-on 2.5Ω, turn-off resistor parameters R nl-off It is 2.5Ω.

[0071] To determine the overload mode drive resistance parameters, given a drive voltage of 20V / -9V, it is necessary to test the turn-on and turn-off waveforms of the IGBT in the FF300R17KE4 module. A sub-module from an actual engineering converter is then slightly modified. Figure 9 This is a schematic diagram of a dual-pulse experimental circuit in this invention.

[0072] Support capacitor C DC Three 470uF / 1200V metal film capacitors are connected in parallel. Equivalent load inductance. L load It is made by winding wire and has an inductance of 40uH.

[0073] To determine the turn-on resistance parameters under overload mode, considering the most stringent 3x current overload condition, turn-on resistances of 2.5Ω, 5Ω, 10Ω, and 15Ω were selected. Under the condition of a collector-emitter voltage of 1000V and a turn-on current of 900A, the turn-on waveforms of the IGBT at different turn-on resistances were measured sequentially, as shown below. Figure 10 As shown, Figure 10 In the diagram, (a) corresponds to a turn-on resistance of 2.5Ω, (b) to 5Ω, (c) to 10Ω, and (d) to 15Ω. The key factors influencing the selection of the turn-on resistance in the turn-on waveform are summarized in Table 1.

[0074] Table 1 Key Factors pass Figure 10 As shown in (a), if the same turn-on resistance parameter of 2.5Ω is used under overload conditions as under rated conditions, strong oscillations will occur during the IGBT turn-on process, which seriously threatens the safe operation of the device. As shown in Table 1, no oscillations occur during device turn-on when the turn-on resistance is 5Ω, 10Ω, or 15Ω, and the IGBT turn-on loss is relatively small when the turn-on resistance is 5Ω. To minimize turn-on losses while ensuring that the IGBT turn-on process does not oscillate under overload conditions, the turn-on resistance parameter for the overload mode can be optimized. R ol-on It is 5Ω.

[0075] To determine the turn-off resistor parameters under overload mode, turn-off resistors of 7.5Ω, 10Ω, 15Ω, and 20Ω were selected respectively. Under the condition of a collector-emitter voltage of 1000V and a turn-off current of 900A, the turn-off waveforms of the IGBTs with different turn-off resistors were measured sequentially, as shown below. Figure 11 As shown, Figure 11 In the diagram, (a) corresponds to a turn-off resistor of 7.5Ω, (b) to 10Ω, (c) to 15Ω, and (d) to 20Ω. The key factors influencing the selection of the turn-off resistor in the turn-off waveform are summarized in Table 2.

[0076] Table 2 Key Factors Depend on Figure 11 As shown in (a), compared to the rated operating condition turn-off resistance parameter of 2.5Ω, when the turn-off resistance is a larger value of 7.5Ω, the voltage spike during the IGBT turn-off process has exceeded the safe value of 1700V specified in the device datasheet. Furthermore, the turn-off process also experiences severe oscillations at this time. Therefore, the rated operating condition turn-off resistance parameter is no longer applicable to overload conditions.

[0077] Table 2 shows that as the turn-off resistance gradually increases from 7.5Ω to 20Ω, the oscillation during the turn-off process gradually weakens, and the turn-off voltage spike also gradually decreases. Under the premise of ensuring that the IGBT turn-off voltage spike does not exceed the limit under overload conditions, minimizing the device's turn-off losses and reducing the degree of oscillation during the turn-off process can optimize the turn-off resistance parameters for the overload mode. R ol-off It is 15Ω.

[0078] Furthermore, to illustrate the necessity of dual-mode operation, if the turn-on resistance is set to 5Ω and the turn-off resistance to 15Ω under rated operating conditions, this will increase the turn-on losses of the IGBT under rated operating conditions, and the rated operating junction temperature of the device will rise. On the one hand, a long-term increase in the operating temperature range will accelerate the aging of the IGBT and shorten the service life of the device; on the other hand, the increase in the rated operating junction temperature will result in insufficient thermal margin of the device, which is not conducive to the active overload of the IGBT.

[0079] Exploration of IGBT full-bridge submodule current overload boundary under dual-mode driving method: To illustrate the role of dual-mode actuation, such as Figure 12 As shown, Figure 12 This is a schematic diagram of two IGBT full-bridge submodules used in an actual engineering SVG in this invention. Figure 12 In this context, SSM represents the submodule under test, and SUT represents the submodule to be tested. C SIndicates the capacitance of the test submodule. C T This indicates the capacitance of the submodule under test. L It is an inductor.

[0080] Two IGBT full-bridge sub-modules used in actual engineering SVG were selected to explore the current overload boundary of the full-bridge sub-modules under gate drive overload mode. The device level of the sub-module under test is 1700V / 300A, and the parameters of the entire test are shown in Table 3.

[0081] Table 3 Parameters of the Torr experiment The capacitor voltages of the two submodules are 1000V. The bridge arm current is controlled by adjusting the phase angle of the voltage between the two submodules via the control board. With a rated operating condition of 300A for the effective value of the bridge arm current between the submodules, the experimental results are as follows: Figure 13 As shown, under the gate drive overload mode, the IGBT full-bridge submodule achieved a 1.5 times rated current overload within 10s and a 2 times rated current overload within 800ms.

[0082] This invention addresses the problems of increased conduction losses and excessive switching stress faced by IGBTs under high overload conditions by proposing a dual-mode driving method. Through theoretical derivation and experimental verification, the mechanisms of increasing the gate voltage to reduce conduction losses and increasing the driving resistance to suppress switching oscillations and overvoltages are clarified, and the driving parameters are optimized. Hardware experiments show that the designed driving board can respond to overload signals in real time and accurately switch modes. Finally, in the full-bridge submodule test, an overload capacity of 1.5 times the rated current within 10 seconds and 2 times the rated current within 800 ms was achieved, verifying the effectiveness of the proposed method in improving the instantaneous overload performance and operational reliability of IGBTs, and providing a new solution for IGBT driving design under high overload conditions.

[0083] The above describes a dual-mode driving method for IGBTs provided by one or more embodiments of the present invention. Based on the same idea, the present invention also provides a corresponding IGBT driving circuit, including: First positive voltage terminal, first negative voltage terminal, second positive voltage terminal, second negative voltage terminal, first switch, second switch, third switch, fourth switch, first turn-on resistor, first turn-off resistor, second turn-on resistor, second turn-off resistor, four input terminals and one output terminal; the output terminal is connected to the gate of the IGBT; The first positive voltage is connected to the output terminal via the first switch and the first turn-on resistor in sequence, and the first input terminal is connected to the first switch; when the first control command is received, the first input terminal is at a high level, the other input terminals are at a low level, the first switch is turned on, and the IGBT is turned on based on the first positive voltage and the first turn-on resistor; The first negative voltage is connected to the output terminal via the second switch and the first turn-off resistor in sequence, and the second input terminal is connected to the second switch; when the second control command is received, the second input terminal is at a high level, the other input terminals are at a low level, the second switch is turned on, and the IGBT is turned off based on the first negative voltage and the first turn-off resistor; The second positive voltage is connected to the output terminal via the third switch and the first turn-on resistor in sequence, and the third input terminal is connected to the third switch; when the third control command is received, the third input terminal is at a high level, the other input terminals are at a low level, the third switch is turned on, and the IGBT is turned on based on the second positive voltage and the second turn-on resistor. The second negative voltage is connected to the output terminal via the fourth switch and the first turn-on resistor in sequence. The fourth input terminal is connected to the fourth switch. When the fourth control command is received, the fourth input terminal is at a high level, the other input terminals are at a low level, the fourth switch is turned on, and the IGBT is turned off based on the second negative voltage and the second turn-off resistor. Wherein, the second positive voltage is greater than the first positive voltage, and the second turn-on resistor is greater than the first turn-on resistor; the second negative voltage is greater than or equal to the first negative voltage, and the second turn-off resistor is greater than the first turn-off resistor.

[0084] For specific limitations on the IGBT drive circuit, please refer to the limitations on the dual-mode drive method of IGBT mentioned above, which will not be repeated here.

[0085] The present invention also provides a computer-readable storage medium storing a computer program that can be used to execute the above-described... Figure 1 The provided method is a dual-mode driving method for IGBTs. Specifically, the computer-readable storage medium is not a physical form of an IGBT driving circuit, but rather stores control instructions for determining IGBT operating conditions and switching IGBT driving modes, and / or determining the second turn-on / turn-off resistor.

[0086] This invention also provides a computer device. At the hardware level, the computer device includes a processor, an internal bus, a network interface, memory, and non-volatile memory, and may also include other hardware required for various operations. The processor reads the corresponding computer program from the non-volatile memory into memory and then executes it to achieve the above-mentioned functions. Figure 1 The provided method provides a dual-mode driving method for IGBTs. Similar to computer-readable storage media, the computer program read and executed by the processor contains control instructions for determining IGBT operating conditions and switching IGBT driving modes, and / or determining the second turn-on / turn-off resistor.

[0087] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the methods described above. Any references to memory, storage, databases, or other media used in the embodiments provided by this invention can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, or optical storage, etc. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0088] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this invention.

Claims

1. A dual-mode driving method for IGBTs, characterized in that, include: Under the rated operating conditions of the IGBT, the IGBT is turned on based on the first positive voltage and the first turn-on resistor, or the IGBT is turned off based on the first negative voltage and the first turn-off resistor. Under IGBT overload conditions, the IGBT is turned on based on the second positive voltage and the second turn-on resistor, or the IGBT is turned off based on the second negative voltage and the second turn-off resistor. Wherein, the second positive voltage is greater than the first positive voltage, and the second turn-on resistor is greater than the first turn-on resistor; The second negative voltage is greater than or equal to the first negative voltage, and the second turn-off resistor is greater than the first turn-off resistor.

2. The dual-mode driving method for IGBT as described in claim 1, characterized in that, Determining the second turn-on resistor specifically includes: The second turn-on resistor is determined with the goal of preventing oscillation during the turn-on process under IGBT overload conditions and minimizing turn-on losses.

3. The dual-mode driving method for IGBT as described in claim 1, characterized in that, Determining the second turn-off resistor specifically includes: The second turn-off resistor is determined with the objectives of preventing oscillation during the turn-off process under IGBT overload conditions, ensuring that the collector-emitter voltage spike during turn-off is less than or equal to the safety limit, and minimizing turn-off losses.

4. The dual-mode driving method for IGBT as described in claim 1, characterized in that, The IGBT model is FF300R17KE4; The first positive voltage is 15V, the first negative voltage is -9V; the first turn-on resistor is 2.5Ω, and the first turn-off resistor is 2.5Ω. The second positive voltage is 20V, the second negative voltage is -9V; the second turn-on resistor is 5Ω, and the second turn-off resistor is 15Ω.

5. A driving circuit for an IGBT, characterized in that, include: First positive voltage terminal, first negative voltage terminal, second positive voltage terminal, second negative voltage terminal, first switch, second switch, third switch, fourth switch, first turn-on resistor, first turn-off resistor, second turn-on resistor, second turn-off resistor, four input terminals and one output terminal; the output terminal is connected to the gate of the IGBT; The first positive voltage is connected to the output terminal via the first switch and the first turn-on resistor in sequence, and the first input terminal is connected to the first switch; when the first control command is received, the first input terminal is at a high level, the other input terminals are at a low level, the first switch is turned on, and the IGBT is turned on based on the first positive voltage and the first turn-on resistor; The first negative voltage is connected to the output terminal via the second switch and the first turn-off resistor in sequence, and the second input terminal is connected to the second switch; when the second control command is received, the second input terminal is at a high level, the other input terminals are at a low level, the second switch is turned on, and the IGBT is turned off based on the first negative voltage and the first turn-off resistor; The second positive voltage is connected to the output terminal via the third switch and the first turn-on resistor in sequence, and the third input terminal is connected to the third switch; when the third control command is received, the third input terminal is at a high level, the other input terminals are at a low level, the third switch is turned on, and the IGBT is turned on based on the second positive voltage and the second turn-on resistor. The second negative voltage is connected to the output terminal via the fourth switch and the first turn-on resistor in sequence. The fourth input terminal is connected to the fourth switch. When the fourth control command is received, the fourth input terminal is at a high level, the other input terminals are at a low level, the fourth switch is turned on, and the IGBT is turned off based on the second negative voltage and the second turn-off resistor. Wherein, the second positive voltage is greater than the first positive voltage, and the second turn-on resistor is greater than the first turn-on resistor; The second negative voltage is greater than or equal to the first negative voltage, and the second turn-off resistor is greater than the first turn-off resistor.

6. A computer-readable storage medium, characterized in that, The storage medium stores a computer program that, when executed by a processor, implements the method as described in any one of claims 1 to 4.

7. A computer device, characterized in that, It includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the computer program, implements the method as described in any one of claims 1 to 4.

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