Circuit structure

Abstract

The utility model provides a circuit structure, comprising a first outer tube circuit which is provided with a first I-GBT (Insulated Gate Bipolar Transistor); the first IGBT is connected with the positive electrode of the power supply; the first inner tube circuit is provided with a second I-GBT (Insulated Gate Bipolar Transistor); the second I-GBT is connected in series with the first I-GBT; the second inner tube circuit is provided with a third I-GBT (Insulated Gate Bipolar Transistor); the third I-GBT is connected in series with the second I-GBT; the second outer tube circuit is provided with a fourth I-GBT (Insulated Gate Bipolar Transistor); the third I-GBT is connected in series with the second I-GBT; the fourth I-GBT is connected in series with the third I-GBT; the fourth IGBT is connected with the negative electrode of the power supply; the voltage absorption circuit is connected with the first IGBT and / or the fourth IGBT in parallel, and a voltage absorption assembly is arranged on the voltage absorption circuit; when the first outer tube circuit or the second outer tube circuit is switched on or switched off, the voltage absorption assembly is used for adjusting the voltage on the circuit structure, and the circuit structure solves the technical problem that the time setting of the I-GBT switch dead zone is unreasonable.

Description

Technical Field

[0001] The utility model relates to the technical field of IGBT control, in particular to a circuit structure. Background Art

[0002] The switching timing requirements for three-level IGBTs must ensure that the on / off timings of the internal and external tubes are complementary. The complementary relationship that must be met is that when one item is turned on, the other item must be turned off accordingly. Due to a certain delay in the hardware control loop, it is impossible to perfectly turn off one item and close the other item instantly. Therefore, the item that is being turned on must be turned off in advance before the other item is turned on. The interval between this turning on and off is the dead time we require.

[0003] The methods for controlling dead zone in the prior art include:

[0004] 1. Based on the performance parameter-time curve, the dead time at which the corresponding performance parameter does not exceed the set threshold is obtained as the candidate dead time. The maximum value among multiple candidate dead times is selected, with a certain margin left as the optimal dead time for the IGBT. The main advantage of this method is that the dead time setting can be increased based on the actual IGBT operating error value, increasing the dead time margin to achieve the ideal dead time. However, this method does not fundamentally solve the problem of dead time delay error.

[0005] 2. Real-time detection of the IGBT freewheeling current and control of the IGBT trigger signal through the freewheeling current detection circuit effectively shifts the IGBT trigger signal and dynamically adjusts the IGBT dead time. Although this method adjusts the IGBT dead time, there is a certain delay in adjusting the IGBT dead time through current detection.

[0006] Therefore, the prior art needs to be further developed. Utility Model Content

[0007] The purpose of the present invention is to overcome the above technical deficiencies and provide a circuit structure to solve the technical problem of unreasonable time setting of the IGBT switch dead zone in the related art.

[0008] To achieve the above technical objectives, the present invention adopts the following technical solutions: providing a circuit structure, comprising: a first outer tube circuit, on which a first IGBT is provided; the first IGBT is connected to the positive electrode of a power supply; a first inner tube circuit, on which a second IGBT is provided; the second IGBT is connected in series with the first IGBT; a second inner tube circuit, on which a third IGBT is provided; the third IGBT is connected in series with the second IGBT; a second outer tube circuit, on which a fourth IGBT is provided; the third IGBT is connected in series with the second IGBT; the fourth IGBT is connected in series with the third IGBT; the fourth IGBT is connected to the negative electrode of the power supply; a voltage absorption circuit, connected in parallel with the first IGBT and / or the fourth IGBT, the voltage absorption circuit being provided with a voltage absorption component; when the first outer tube circuit or the second outer tube circuit is turned on or off, the voltage absorption component is used to adjust the voltage on the circuit structure.

[0009] Furthermore, the voltage absorption circuit includes: a first voltage absorption circuit, one end of the first voltage absorption circuit is connected to the circuit between the positive pole of the power supply and the first IGBT, and the other end of the first voltage absorption circuit is connected to the circuit between the first IGBT and the second IGBT; the voltage absorption component is arranged on the first voltage absorption circuit.

[0010] Furthermore, the voltage absorption component includes a resistor R5, a capacitor C1 and a diode D3; the resistor R5, the capacitor C1 and the diode D3 are sequentially connected in series to the first voltage absorption circuit.

[0011] Furthermore, the capacitance of the capacitor C1 ranges from 1nF to 3nF; the withstand voltage range of the capacitor C1 is 500V to 1000V; and / or the resistance of the resistor R5 ranges from 5Ω to 10Ω; and / or the withstand voltage range of the diode D3 is 500V to 1000V.

[0012] Furthermore, the voltage absorption circuit includes: a second voltage absorption circuit, one end of the second voltage absorption circuit is connected to the circuit between the negative electrode of the power supply and the fourth IGBT, and the other end of the second voltage absorption circuit is connected to the circuit between the fourth IGBT and the third IGBT; the voltage absorption component is arranged on the second voltage absorption circuit.

[0013] Furthermore, the voltage absorption component includes a resistor R6, a capacitor C2 and a diode D4; the resistor R6, the capacitor C2 and the diode D4 are sequentially connected in series in the second voltage absorption circuit.

[0014] Furthermore, the capacitance of the capacitor C2 ranges from 1nF to 3nF; the withstand voltage range of the capacitor C1 ranges from 500V to 1000V; and / or the resistance of the resistor R6 ranges from 5Ω to 10Ω; and / or the withstand voltage range of the diode D4 ranges from 500V to 1000V.

[0015] Furthermore, the circuit structure includes: a first outer tube drive circuit, the first outer tube drive circuit is connected to the G pole of the first IGBT, and the first outer tube drive circuit is provided with a resistor R1 for driving the first IGBT to be turned on; a first inner tube drive circuit, the first inner tube drive circuit is connected to the G pole of the second IGBT, and the first inner tube drive circuit is provided with a resistor R3 for driving the second IGBT to be turned on; wherein the resistance value of the resistor R1 is smaller than the resistance value of the resistor R3.

[0016] Furthermore, the first outer tube drive circuit is provided with a resistor R2 and a diode D1 for driving the first IGBT to turn off; the resistor R2 and the diode D1 are both connected in parallel with the resistor R1; the first inner tube drive circuit is provided with a resistor R4 and a diode D2 for driving the second IGBT to turn off; the resistor R4 and the diode D2 are both connected in parallel with the resistor R3; wherein the resistance value of the resistor R1 and the resistor R2 connected in parallel is greater than the resistance value of the resistor R3 and the resistor R4 connected in parallel.

[0017] Furthermore, the circuit structure includes: a second outer tube drive circuit, the second outer tube drive circuit is connected to the G pole of the fourth IGBT, and the second outer tube drive circuit is provided with a resistor R7 for driving the fourth IGBT to be turned on; a second inner tube drive circuit, the second inner tube drive circuit is connected to the G pole of the third IGBT, and the second inner tube drive circuit is provided with a resistor R5 for driving the third IGBT to be turned on; wherein the resistance value of the resistor R7 is smaller than the resistance value of the resistor R5.

[0018] Furthermore, the second outer tube drive circuit is provided with a resistor R8 and a diode D4 for driving the fourth IGBT to turn off; the resistor R8 and the diode D4 are both connected in parallel with the resistor R7; the second inner tube drive circuit is provided with a resistor R6 and a diode D3 for driving the second IGBT to turn off; the resistor R6 and the diode D3 are connected in parallel with the resistor R5; wherein, the resistance of the resistor R7 and the resistor R8 connected in parallel is greater than the resistance of the resistor R5 and the resistor R6 connected in parallel.

[0019] Beneficial effects:

[0020] The circuit structure of the utility model includes a first outer tube circuit, on which a first IGBT is provided; the first IGBT is connected to the positive electrode of a power supply; a first inner tube circuit, on which a second IGBT is provided; the second IGBT is connected in series with the first IGBT; a second inner tube circuit, on which a third IGBT is provided; the third IGBT is connected in series with the second IGBT; a second outer tube circuit, on which a fourth IGBT is provided; the third IGBT is connected in series with the second IGBT; a fourth IGBT is connected in series with the third IGBT; the fourth IGBT is connected to the negative electrode of the power supply; a voltage absorption circuit, which is connected in parallel with the first IGBT and / or the fourth IGBT, and a voltage absorption component is provided on the voltage absorption circuit; when the first outer tube circuit or the second outer tube circuit is turned on or off, the voltage absorption component is used to adjust the voltage on the circuit structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural diagram of the circuit structure adopted in the embodiment of the present utility model;

[0022] Figure 2 This is a schematic structural diagram of a first inner tube driving circuit of the circuit structure adopted in an embodiment of the present utility model;

[0023] Figure 3 This is a schematic structural diagram of a second inner tube driving circuit of the circuit structure adopted in an embodiment of the present utility model;

[0024] Figure 4 This is a schematic structural diagram of a second inner tube driving circuit of the circuit structure adopted in an embodiment of the present utility model;

[0025] Figure 5 This is a schematic structural diagram of the second outer tube driving circuit of the circuit structure adopted in the embodiment of the present utility model;

[0026] Figure 6 Schematic diagram of voltage changes in each tube circuit of a three-level IGBT in the prior art;

[0027] Figure 7 This is a schematic diagram of the voltage changes of each tube circuit in the circuit structure of the utility model.

[0028] The above drawings include the following reference numerals:

[0029] 1. First outer tube circuit; 2. First inner tube circuit; 3. Second inner tube circuit; 4. Second outer tube circuit; 5. Voltage absorption circuit; 51. First voltage absorption circuit; 52. Second voltage absorption circuit; 6. First outer tube drive circuit; 7. First inner tube drive circuit; 8. Second inner tube drive circuit; 9. Second outer tube drive circuit. DETAILED DESCRIPTION

[0030] In order to enable those skilled in the art to better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings 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 in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of this application.

[0031] See also Figures 1 to 7 According to an embodiment of the present invention, a circuit structure is provided, including: a first outer tube circuit 1, on which a first IGBT is provided; the first IGBT is connected to the positive electrode of a power supply; a first inner tube circuit 2, on which a second IGBT is provided; the second IGBT is connected in series with the first IGBT; a second inner tube circuit 3, on which a third IGBT is provided; the third IGBT is connected in series with the second IGBT; a second outer tube circuit 4, on which a fourth IGBT is provided; the third IGBT is connected in series with the second IGBT; a fourth IGBT is connected in series with the third IGBT; the fourth IGBT is connected to the negative electrode of the power supply; a voltage absorption circuit 5, which is connected in parallel with the first IGBT and / or the fourth IGBT, and the voltage absorption circuit 5 is provided with a voltage absorption component; when the first outer tube circuit 1 or the second outer tube circuit 4 is turned on or off, the voltage absorption component is used to adjust the voltage on the circuit structure.

[0032] The switching timing requirements for three-level IGBTs require that the on / off timings of the inner and outer transistors complement each other, i.e., the first outer transistor circuit 1 complements the second inner transistor circuit 3, and the first inner transistor circuit 2 complements the second outer transistor circuit 4. The complementary relationship that must be satisfied is that when one item is turned on, the other item must be turned off accordingly. Due to a certain delay in the hardware control loop, it is impossible to perfectly turn off one item and close the other instantly. Therefore, the item being turned on must be turned off in advance before the other item is turned on. The interval between turning on and off is the required dead time.

[0033] See also Figure 6 、 Figure 7 Experimental results revealed that when the outer tubes (i.e., first outer tube circuit 1 and second outer tube circuit 4) are turned off, a delayed shutdown and a voltage step-down phenomenon occur. According to the characteristics of three-level IGBT switches, when the two complementary circuits perform complementary switching operations continuously, the other two circuits maintain continuous open-circuit operation. This causes fluctuations in the intermediate phase neutral line N from the continuous voltage conversion between AC and DC, resulting in a certain voltage inside the neutral line. When the outer tubes switch, the voltage still remains inside them, resulting in a step-like, gradual decrease in voltage. This delayed reduction, which leaves voltage, significantly affects the shutdown effect.

[0034] By adopting the circuit structure of this embodiment, freewheeling diodes are added to the two external tubes, and the residual voltage is absorbed by the voltage absorption circuit 5. From the hardware perspective, the dead zone interval is effectively widened, allowing the voltage to drop to a low level more smoothly when the tube is turned off. Then, the dead zone time is set, which solves the technical problem of unreasonable time setting of the IGBT switch dead zone in the related art.

[0035] In the circuit structure of this embodiment, see Figure 1 The voltage absorption circuit 5 includes a first voltage absorption circuit 51, one end of which is connected to the circuit between the positive electrode of the power supply and the first IGBT, and the other end of which is connected to the circuit between the first IGBT and the second IGBT. A voltage absorption component is provided on the first voltage absorption circuit 51. In this way, the step voltage generated at the first external tube circuit 1 can be precisely controlled.

[0036] See also Figure 1 In the circuit structure of this embodiment, the voltage absorption component includes a resistor R5, a capacitor C1, and a diode D3; these components are connected in series to the first voltage absorption circuit 51. Thus, capacitor C1 absorbs the step voltage generated in the first external tube circuit 1, and a freewheeling diode is added to the voltage absorption circuit 5 to prevent voltage backflow and affect current flow.

[0037] In the circuit structure of this embodiment, see Figure 1The capacitance of capacitor C1 ranges from 1nF to 3nF; the withstand voltage of capacitor C1 ranges from 500V to 1000V; and / or the resistance of resistor R5 ranges from 5Ω to 10Ω; and / or the withstand voltage of diode D3 ranges from 500V to 1000V. In this way, by controlling the parameters of the above-mentioned electrical components within a reasonable range, the step voltage can be eliminated without affecting the normal operation of the circuit.

[0038] See also Figure 1 In the circuit structure of this embodiment, the voltage absorption circuit 5 includes a second voltage absorption circuit 52, one end of which is connected to the circuit between the negative electrode of the power supply and the fourth IGBT, and the other end of which is connected to the circuit between the fourth IGBT and the third IGBT. The voltage absorption component is disposed on the second voltage absorption circuit 52. This allows for precise control of the step voltage generated at the second external tube circuit 4.

[0039] In the circuit structure of this embodiment, see Figure 1 The voltage absorption component includes a resistor R6, a capacitor C2, and a diode D4; these components are connected in series to the second voltage absorption circuit 52. Thus, capacitor C1 absorbs the step voltage generated in the first external tube circuit 1, and a freewheeling diode is added to the voltage absorption circuit 5 to prevent voltage backflow and affect the current flow.

[0040] In the circuit structure of this embodiment, the capacitance of capacitor C2 ranges from 1nF to 3nF; the withstand voltage of capacitor C1 ranges from 500V to 1000V; and / or the resistance of resistor R6 ranges from 5Ω to 10Ω; and / or the withstand voltage of diode D4 ranges from 500V to 1000V. In this way, by controlling the parameters of the above-mentioned electrical components within a reasonable range, the step voltage can be eliminated without affecting the normal operation of the circuit.

[0041] In the circuit structure of this embodiment, see Figure 3 、 Figure 4 The circuit structure includes: a first outer tube drive circuit 6, the first outer tube drive circuit 6 is connected to the G pole of the first IGBT, and the first outer tube drive circuit 6 is provided with a resistor R1 for driving the first IGBT to be turned on; a first inner tube drive circuit 7, the first inner tube drive circuit 7 is connected to the G pole of the second IGBT, and the first inner tube drive circuit 7 is provided with a resistor R3 for driving the second IGBT to be turned on; wherein the resistance value of the resistor R1 is smaller than the resistance value of the resistor R3.

[0042] Specifically, R1 is the outer resistor's off-state resistance, and R3 is the inner resistor's off-state resistance. To accelerate the outer resistor's off-state, the resistance should be smaller, meaning R1 < R3. This allows the outer resistor to turn off earlier, preventing it from affecting the circuit.

[0043] In the circuit structure of this embodiment, see Figure 2 、 Figure 3 The first outer tube driving circuit 6 is provided with a resistor R2 and a diode D1 for driving the first IGBT to turn off; the resistor R2 and the diode D1 are both connected in parallel with the resistor R1; the first inner tube driving circuit 7 is provided with a resistor R4 and a diode D2 for driving the second IGBT to turn off; the resistor R4 and the diode D2 are both connected in parallel with the resistor R3; wherein the resistance value of the resistor R1 and the resistor R2 connected in parallel is greater than the resistance value of the resistor R3 and the resistor R4 connected in parallel.

[0044] Specifically, as a three-level IGBT, the first turn-on timing must meet the requirement that the two inner transistors are turned on first and the two outer transistors are turned on later; therefore, the resistance requirement of the turn-on resistor is that the inner transistor is smaller than the outer transistor, that is, R1 and R2> R3 and R4, so as to meet the turn-on requirement.

[0045] In the circuit structure of this embodiment, see Figure 4 、 Figure 5 The circuit structure includes: a second outer transistor drive circuit 9, connected to the G terminal of the fourth IGBT and equipped with a resistor R7 for driving the fourth IGBT on; a second inner transistor drive circuit 8, connected to the G terminal of the third IGBT and equipped with a resistor R5 for driving the third IGBT on; wherein the resistance of resistor R7 is smaller than that of resistor R5. This allows the outer transistor to be turned off earlier, preventing the shutdown from affecting the circuit.

[0046] In the circuit structure of this embodiment, the second outer transistor drive circuit 9 is equipped with a resistor R8 and a diode D4 for driving the fourth IGBT off. Resistor R8 and diode D4 are connected in parallel with resistor R7. The second inner transistor drive circuit 8 is equipped with a resistor R6 and a diode D3 for driving the second IGBT off. Resistor R6 and diode D3 are connected in parallel with resistor R5. The resistance of resistors R7 and R8 in parallel is greater than the resistance of resistors R5 and R6 in parallel. This ensures that the turn-on resistance of the inner transistor is lower than that of the outer transistor, thereby meeting the turn-on requirements. The first turn-on sequence ensures that the two inner transistors turn on first, followed by the two outer transistors.

[0047] Example 1:

[0048] The switching timing requirements for three-level IGBTs require that the on / off timings of the inner and outer transistors complement each other, i.e., the first outer transistor circuit 1 complements the second inner transistor circuit 3, and the first inner transistor circuit 2 complements the second outer transistor circuit 4. The complementary relationship that must be satisfied is that when one item is turned on, the other item must be turned off accordingly. Due to a certain delay in the hardware control loop, it is impossible to perfectly turn off one item and close the other instantly. Therefore, the item being turned on must be turned off in advance before the other item is turned on. The interval between turning on and off is the required dead time.

[0049] See also Figure 6 、 Figure 7 Experimental results revealed that when the outer tubes (i.e., first outer tube circuit 1 and second outer tube circuit 4) are turned off, a delayed shutdown and a voltage step-down phenomenon occur. According to the characteristics of three-level IGBT switches, when the two complementary circuits perform complementary switching operations continuously, the other two circuits maintain continuous open-circuit operation. This causes fluctuations in the intermediate phase neutral line N from the continuous voltage conversion between AC and DC, resulting in a certain voltage inside the neutral line. When the outer tubes switch, the voltage still remains inside them, resulting in a step-like, gradual decrease in voltage. This delayed reduction, which leaves voltage, significantly affects the shutdown effect.

[0050] With the circuit structure of this embodiment, freewheeling diodes are added to the two outer tubes, and the residual voltage is absorbed by the voltage absorption circuit 5 .

[0051] As the voltage absorption circuit 5, the capacitance of C1 and C2 should not be too large. Too large will not only affect the efficiency but also slow down the absorption. Therefore, the capacitance range should be 1nF to 3nF, and the withstand voltage range should be 500V to 1000V. If the resistance of R5 and R6 is too large, it will also affect the absorption time. The resistance is required to be between 5Ω and 10Ω, and the withstand voltage range is also 500V to 1000V. The diode can also be selected with a withstand voltage range of 500V to 1000V.

[0052] In practice, the PWM control signal that controls the switching tube is generated by the control board and then processed by the IGBT. This long circuit may introduce a certain delay, resulting in incomplete dead-time control at the start of the switching tube operation. Therefore, we can optimize the time it takes for the control signal to reach the IGBT in the drive circuit. By combining diodes and resistors, we can delay the turn-on time and advance the turn-off time.

[0053] The relationship should meet the following conditions:

[0054] R1 is the turn-off resistor of the outer tube, and R3 is the turn-off resistor of the inner tube. In order to make the turn-off time of the outer tube earlier, the resistance value should be smaller, that is, R1<R3.

[0055] When the IGBT turns on by issuing a pulse, the diode conducts, connecting the two resistors in parallel. However, as a characteristic of a three-level IGBT, when two of the two transistors perform complementary continuous switching operations, the other two maintain continuous on-state. Therefore, after the first on-state after power-up, the two transistors that continue to turn on continue turning on, while the other two transistors that continue to switch on continue switching until the cycle ends. Therefore, after the first run command is issued after power-up, all four transistors must turn on. As with a three-level IGBT, the first turn-on sequence must ensure that the two inner transistors turn on first, followed by the two outer transistors. Therefore, the turn-on resistor value requirement is that the inner transistors must be smaller than the outer transistors, meaning R1 and R2 > R3 and R4.

[0056] For example, if R1 is 20Ω, R2 is 20Ω, R5 is 25Ω, and R6 is 15Ω, then the off-resistance of the outer and inner transistors is 20Ω to 25Ω; and the on-resistance of the outer and inner transistors is 10Ω to 9.375Ω, which meets the requirements. In actual operation, if the off-resistance of the inner transistor is slightly higher, it will shut down later. Similarly, if the on-resistance of the outer transistor is slightly higher, it will turn on later, ensuring synchronization with the inner transistor's shutdown.

[0057] The drive resistance range requirement should be determined according to the IGBT model and specification. The off-resistance range is between 15Ω and 35Ω, and the on-resistance range is between 9Ω and 15Ω. The above relationship must be maintained within this range.

[0058] Example 2:

[0059] Specifically, when the IGBT is off, diode D1 is non-conductive, and the drive signal enters the circuit through only one resistor, R1. When the IGBT is on, the front-end voltage is high, diode D1 conducts, and the total resistance of the drive circuit equals the parallel resistance of R1 and R2. The difference in resistance before and after the switch affects the switching timing.

[0060] R1 is 20Ω, R2 is 20Ω, R5 is 25Ω, and R6 is 15Ω. Therefore, the off-resistance of the outer tube T1 and the inner tube T3 is 20Ω to 25Ω. The smaller off-resistance of the outer tube T1 results in a faster turn-off. The on-resistance of the outer tube T1 and the inner tube T3 is 10Ω to 9.375Ω. The larger turn-on resistance of the outer tube T1 results in a later turn-on. Because the response time was less than 2µs before adjustment, this indicates that we need to increase the response time. The faster turn-off of the outer tube T1 results in an earlier response, while the turn-on resistance of the inner tube T3 remains the same, thus extending the dead time. The later turn-on of the outer tube T1 and the same turn-on resistance of the inner tube T3 also extend the dead time.

[0061] The drive resistance range requirement should be determined according to the IGBT model and specification. The off-resistance range is between 15Ω and 35Ω, and the on-resistance range is between 9Ω and 15Ω. The above relationship must be maintained within this range.

[0062] The current structure of this embodiment is described as follows:

[0063] See also Figure 6 The four channels represent the VCE switching waveforms of the four IGBTs, T1 (yellow), T2 (green), T3 (blue), and T4 (red); these waveforms adhere to the complementary relationship described above: T1 and T3 complement each other, and T2 and T4 complement each other. This diagram primarily illustrates the issues that occurred when switching T2 and T4 before rectification. When the voltage increase of the internal transistor T2 (green) is initiated (at the position of the vertical cursor X1), the complementary transistor T4 (red) should be completely at a low voltage. However, due to the stepped freewheeling voltage in the diagram, the complementary transistor does not turn off when T2 turns on, posing a safety hazard.

[0064] In addition, the distance ΔX between the position of the vertical cursor X2 and X1 is 2us, which is the dead time we require. However, the actual T4 shutdown action occurs after this, which means that the dead time during actual operation is less than 2us. If the control is shut down too quickly, there may be poor connection, which is also a safety hazard.

[0065] See also Figure 7 This figure shows the voltage profile of each transistor in the circuit structure of this embodiment. After adjustment, T4 (red), which previously exhibited a step-like shutdown pattern, now drops to a low level more smoothly. Its complementary transistor, T2 (green), also switches (raises its voltage) only after it has completely dropped to a low level. Comparing this with the previous figure, the interval ΔX between cursors X1 and X2 is 2µs, indicating that the switching interval meets the 2µs requirement, thus satisfying the dead-band setting. ΔX simply represents the difference between X1 and X2; its positive or negative value does not affect the actual measurement results.

[0066] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in a sequence other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0067] Optionally, the specific examples in this embodiment may refer to the examples described in the above embodiments, and this embodiment will not be described in detail here.

[0068] The serial numbers of the above embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0069] In the above embodiments of the present application, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments.

[0070] The above is only a preferred embodiment of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A circuit structure, characterized in that: include: A first external tube circuit (1), wherein a first IGBT is provided on the first external tube circuit (1); the first IGBT is connected to the positive electrode of a power supply; A first inner tube circuit (2), wherein a second IGBT is provided on the first inner tube circuit (2); the second IGBT is connected in series with the first IGBT; A second inner tube circuit (3), wherein a third IGBT is provided on the second inner tube circuit (3); the third IGBT is connected in series with the second IGBT; A second external tube circuit (4), wherein a fourth IGBT is provided on the second external tube circuit (4); the third IGBT is connected in series with the second IGBT; the fourth IGBT is connected in series with the third IGBT; and the fourth IGBT is connected to the negative electrode of the power supply; A voltage absorption circuit (5) is connected in parallel with the first IGBT and / or the fourth IGBT, and a voltage absorption component is provided on the voltage absorption circuit (5); when the first external tube circuit (1) or the second external tube circuit (4) is turned on or off, the voltage absorption component is used to adjust the voltage on the circuit structure.

2. The circuit structure according to claim 1, wherein: The voltage absorption circuit (5) comprises: A first voltage absorption circuit (51), one end of the first voltage absorption circuit (51) is connected to the circuit between the positive electrode of the power supply and the first IGBT, and the other end of the first voltage absorption circuit (51) is connected to the circuit between the first IGBT and the second IGBT; the voltage absorption component is arranged on the first voltage absorption circuit (51).

3. The circuit structure according to claim 2, wherein: The voltage absorption component includes a resistor R5, a capacitor C1, and a diode D3; the resistor R5, the capacitor C1, and the diode D3 are sequentially connected in series to the first voltage absorption circuit (51).

4. The circuit structure according to claim 3, wherein: The capacitance of the capacitor C1 ranges from 1nF to 3nF; the withstand voltage of the capacitor C1 ranges from 500V to 1000V; and / or, The resistance of the resistor R5 ranges from 5Ω to 10Ω; and / or, The withstand voltage range of the diode D3 is 500V to 1000V.

5. The circuit structure according to claim 1, wherein: The voltage absorption circuit (5) comprises: A second voltage absorption circuit (52), one end of the second voltage absorption circuit (52) is connected to the circuit between the negative electrode of the power supply and the fourth IGBT, and the other end of the second voltage absorption circuit (52) is connected to the circuit between the fourth IGBT and the third IGBT; the voltage absorption component is arranged on the second voltage absorption circuit (52).

6. The circuit structure according to claim 5, characterized in that: The voltage absorption component includes a resistor R6, a capacitor C2, and a diode D4; the resistor R6, the capacitor C2, and the diode D4 are sequentially connected in series to the second voltage absorption circuit (52).

7. The circuit structure according to claim 6, characterized in that: The capacitance of the capacitor C2 ranges from 1nF to 3nF; the withstand voltage of the capacitor C1 ranges from 500V to 1000V; and / or, The resistance of the resistor R6 ranges from 5Ω to 10Ω; and / or, The withstand voltage range of the diode D4 is 500V to 1000V.

8. The circuit structure according to claim 1, wherein: The circuit structure includes: a first external tube drive circuit (6), the first external tube drive circuit (6) being connected to the G pole of the first IGBT, and the first external tube drive circuit (6) being provided with a resistor R1 for driving the first IGBT to conduct; A first inner tube drive circuit (7) is connected to the G pole of the second IGBT, and a resistor R3 is provided on the first inner tube drive circuit (7) for driving the second IGBT to conduct; wherein the resistance value of the resistor R1 is smaller than the resistance value of the resistor R3.

9. The circuit structure according to claim 8, characterized in that: The first external tube driving circuit (6) is provided with a resistor R2 and a diode D1 for driving the first IGBT to turn off; the resistor R2 and the diode D1 are both connected in parallel with the resistor R1; The first inner tube driving circuit (7) is provided with a resistor R4 and a diode D2 for driving the second IGBT to turn off; the resistor R4 and the diode D2 are both connected in parallel with the resistor R3; wherein the resistance value of the resistor R1 connected in parallel with the resistor R2 is greater than the resistance value of the resistor R3 connected in parallel with the resistor R4.

10. The circuit structure according to claim 1, wherein: The circuit structure includes: a second external tube drive circuit (9), the second external tube drive circuit (9) being connected to the G pole of the fourth IGBT, and the second external tube drive circuit (9) being provided with a resistor R7 for driving the fourth IGBT to conduct; A second inner tube drive circuit (8), wherein the second inner tube drive circuit (8) is connected to the G pole of the third IGBT, and a resistor R5 for driving the third IGBT to conduct is provided on the second inner tube drive circuit (8); wherein the resistance value of the resistor R7 is smaller than the resistance value of the resistor R5.

11. The circuit structure according to claim 10, characterized in that: The second external tube driving circuit (9) is provided with a resistor R8 and a diode D4 for driving the fourth IGBT to turn off; the resistor R8 and the diode D4 are both connected in parallel with the resistor R7; The second inner tube driving circuit (8) is provided with a resistor R6 and a diode D3 for driving the second IGBT to turn off; the resistor R6 and the diode D3 are connected in parallel with the resistor R5; wherein the resistance value of the resistor R7 and the resistor R8 connected in parallel is greater than the resistance value of the resistor R5 and the resistor R6 connected in parallel.

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