Switching tube driving circuit with adjustable gate capacitance and load circuit

Abstract

The utility model relates to the field of power electronic testing, in particular to a switching tube driving circuit with adjustable gate capacitance and a load circuit, the switching tube driving circuit is connected with a switching tube and comprises a driving chip, an output end of the driving chip is connected with a gate electrode of the switching tube, and an acquisition end of the driving chip is connected with a collector electrode and an emitter electrode of the switching tube. Acquiring a voltage waveform to obtain a voltage change rate of the switching tube; the first end of the gate capacitor is connected with the gate electrode of the switching tube, the second end of the gate capacitor is connected with the emitting electrode of the switching tube, the driving chip outputs a capacitance control signal based on the voltage change rate, and the gate capacitor is controllably adjusted to a capacitance value corresponding to the capacitance control signal. According to the utility model, a fixed gate pole capacitor is changed into a gate pole capacitor with an adjustable capacitance value, so that the adjustable gate pole capacitor can be dynamically adjusted according to the numerical value of the voltage change rate under different working conditions, the switching loss and temperature rise are reduced, and the performance of a switching tube is improved.

Description

Technical Field

[0001] The utility model relates to the field of power electronic testing, in particular to a switch tube drive circuit and a load circuit. Background Art

[0002] IGBTs, as a mainstream power semiconductor device, are widely used in industries such as new energy vehicles, photovoltaics, and wind power generation. In practical applications, IGBT drivers often require fixed gate capacitance to reduce the voltage change rate (dv / dt) during switching. However, this increases switching losses, a significant drawback. Since the need to reduce dv / dt during switching is relatively rare in practical applications, making the gate capacitance of the IGBT driver circuit precisely adjustable is crucial.

[0003] Most common IGBT drive circuits on the market have fixed gate capacitance. In the actual application conditions of IGBT devices, it is equivalent to configuring gate capacitance in each operating condition that is only needed under the worst operating conditions. Therefore, the capacitance of the gate capacitance depends on the worst operating condition scenario, resulting in excessive capacitance in most scenarios, high overall switching loss and temperature rise, which is not conducive to the ultimate performance of the IGBT. Utility Model Content

[0004] The purpose of this utility model is to provide a switch tube driving circuit with adjustable gate capacitance to solve the above technical problems;

[0005] The purpose of the present utility model is also to provide a load circuit to solve the above technical problems.

[0006] The technical problem solved by the present invention can be achieved by adopting the following technical solutions:

[0007] A switch tube driving circuit with adjustable gate capacitance is connected to a switch tube, comprising:

[0008] A driver chip, wherein the output end of the driver chip is connected to the gate of the switch tube, and the acquisition end of the driver chip is connected to the collector and emitter of the switch tube to acquire the voltage waveform and obtain the voltage change rate of the switch tube;

[0009] A gate capacitor, wherein a first end of the gate capacitor is connected to the gate of the switching tube, and a second end of the gate capacitor is connected to the emitter of the switching tube. The driver chip outputs a capacitance control signal based on the voltage change rate, and the gate capacitor can be controllably adjusted to a capacitance value corresponding to the capacitance control signal.

[0010] Preferably, the gate capacitor has a plurality of numerical gears, the voltage change rate is divided into change intervals having the same number as the numerical gears, and each change interval corresponds to one numerical gear.

[0011] Preferably, the capacitance range of the gate capacitor is 0nF to 10nF.

[0012] Preferably, the voltage change rate of the switching tube ranges from 0V / us to 5000V / us.

[0013] Preferably, the driver chip includes a first collecting terminal and a second collecting terminal, the first collecting terminal of the driver chip is connected to the collector of the switch tube, and the second collecting terminal of the driver chip is connected to the emitter of the switch tube.

[0014] Preferably, a driving resistor is further included, and the output end of the driving chip is connected to the gate of the switching tube through the driving resistor.

[0015] Preferably, the switching tube is an IGBT tube.

[0016] A load circuit includes a switch branch, the switch branch including a first switch tube and a second switch tube connected between a first voltage terminal and a second voltage terminal, the collector of the first switch tube being connected to the first voltage terminal, the collector of the second switch tube being connected to the emitter of the first switch tube, the emitter of the second switch tube being connected to the second voltage terminal, the emitter of the first switch tube being the AC output terminal of the switch branch, the second switch tube being connected to the switch tube drive circuit, the output terminal of the driver chip being connected to the gate of the second switch tube, the acquisition terminal of the driver chip being connected to the collector and emitter of the second switch tube, the first terminal of the gate capacitor being connected to the gate of the second switch tube, and the second terminal of the gate capacitor being connected to the emitter of the second switch tube.

[0017] Preferably, the first switch tube is a normally closed switch tube.

[0018] Preferably, it also includes,

[0019] a voltage source, wherein a forward voltage terminal of the voltage source is the first voltage terminal, and a reverse voltage terminal of the voltage source is the second voltage terminal;

[0020] a bus capacitor, wherein a first end of the bus capacitor is connected to the first voltage end, and a second end of the bus capacitor is connected to the second voltage end;

[0021] A load branch, wherein a first end of the load branch is connected to the first voltage end, and a second end of the load branch is connected to the AC output end.

[0022] The beneficial effects of the present invention are as follows: due to the adoption of the above technical solution, the present invention changes the fixed gate capacitor into a gate capacitor with adjustable capacitance, so that the adjustable gate capacitor can be dynamically adjusted according to the numerical value of the voltage change rate under different working conditions, thereby reducing switching loss and temperature rise, and is beneficial to improving the performance of the switching tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of the structure of the switch tube driving circuit in an embodiment of the present utility model;

[0024] Figure 2 Schematic diagram of a load circuit in an embodiment of the present utility model;

[0025] Figure 3 Schematic diagram of a load circuit in the prior art. DETAILED DESCRIPTION

[0026] 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 embodiments described 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 making creative efforts are within the scope of protection of the present invention.

[0027] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features therein can be combined with each other.

[0028] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but they are not intended to limit the present invention.

[0029] A switch tube driving circuit 1 with adjustable gate capacitance, such as Figure 1 , Figure 2 As shown, a switch tube Q is connected, including:

[0030] Driver chip S1, the output end of driver chip S1 is connected to the gate of switch tube Q, and the acquisition end of driver chip S1 is connected to the collector and emitter of switch tube Q to collect voltage waveform and obtain the voltage change rate of switch tube Q;

[0031] A gate capacitor C1 with adjustable capacitance has its first end connected to the gate of the switch tube Q and its second end connected to the emitter of the switch tube Q. The driver chip S1 outputs a capacitance control signal based on the voltage change rate, and the gate capacitor C1 can be controllably adjusted to a capacitance value corresponding to the capacitance control signal.

[0032] The utility model provides a switch tube driving circuit 1 with adjustable gate capacitance, which can dynamically adjust the gate-level gate capacitance C1 according to the working state of the switch tube Q, specifically the voltage change rate, to optimize the driving performance and reduce the switching loss and temperature rise.

[0033] Specifically, the driver chip S1 is connected to the collector and emitter of the switch tube Q, and monitors the collector-emitter voltage (V CE ), by V CE By detecting the waveform, the driver chip S1 can calculate the voltage change rate dv / dt.

[0034] More specifically, the driver chip S1 determines the absolute value of the voltage change rate dv / dt in real time, and adjusts the gate capacitor C1 according to the value.

[0035] In a preferred embodiment, the gate capacitor C1 has several numerical gears, and the voltage change rate is divided into change intervals equal to the number of the numerical gears, and each change interval corresponds to a numerical gear.

[0036] In a preferred embodiment, the capacitance of the gate capacitor C1 ranges from 0nF to 10nF.

[0037] In a preferred embodiment, the voltage change rate of the switch tube Q ranges from 0V / us to 5000V / us.

[0038] Specifically, the capacitance of the gate capacitor C1 includes five numerical ranges, namely 0nF, 2.2nF, 4.7nF, 6.8nF, and 10nF.

[0039] The absolute value of the voltage change rate dv / dt in this utility model is divided into five intervals, which are

[0040] 0V / us<|dv / dt|≤1000V / us;

[0041] 1000V / us<|dv / dt|≤2000V / us;

[0042] 2000V / us<|dv / dt|≤3000V / us;

[0043] 3000V / us<|dv / dt|≤4000V / us;

[0044] 4000V / us<|dv / dt|≤5000V / us.

[0045] The corresponding relationship between the voltage change rate dv / dt and the numerical position of the gate capacitance C1 is:

[0046] 0V / us<|dv / dt|≤1000V / us corresponds to 0nF;

[0047] 1000V / us<|dv / dt|≤2000V / us corresponds to 2.2nF;

[0048] 2000V / us<|dv / dt|≤3000V / us corresponds to 4.7nF;

[0049] 3000V / us<|dv / dt|≤4000V / us corresponds to 6.8nF;

[0050] 4000V / us<|dv / dt|≤5000V / us corresponds to 10nF;

[0051] In a preferred embodiment, the driver chip S1 includes a first collecting terminal and a second collecting terminal. The first collecting terminal of the driver chip S1 is connected to the collector of the switch tube Q, and the second collecting terminal of the driver chip S1 is connected to the emitter of the switch tube Q.

[0052] In a preferred embodiment, a driving resistor R1 is further included, and the output end of the driving chip S1 is connected to the gate of the switch tube Q through the driving resistor R1.

[0053] In a preferred embodiment, the switch tube Q is an IGBT tube.

[0054] Specifically, the main function of the gate capacitor C1 is to control the voltage change rate during the IGBT switching process. The IGBT switching process includes two stages: turn-on and turn-off. The size of the gate capacitor C1 will directly affect the switching speed and switching loss. By adjusting the gate capacitor C1 according to the real-time voltage change rate, the switching process can be optimized under different working conditions to achieve lower switching losses.

[0055] A load circuit, such as Figure 2 As shown, a switch branch is included, which includes a first switch tube Q1 and a second switch tube Q2 connected between a first voltage terminal P1 and a second voltage terminal P2, a collector of the first switch tube Q1 is connected to the first voltage terminal P1, a collector of the second switch tube Q2 is connected to the emitter of the first switch tube Q1, an emitter of the second switch tube Q2 is connected to the second voltage terminal P2, and the emitter of the first switch tube Q1 is the AC output terminal P3 of the switch branch. It is characterized in that the second switch tube Q2 is connected to the switch tube driving circuit 1 in any embodiment, the output terminal of the driver chip S1 is connected to the gate of the second switch tube Q2, the collection terminal of the driver chip S1 is connected to the collector and emitter of the second switch tube Q2, the first terminal of the gate capacitor C1 is connected to the gate of the second switch tube Q2, and the second terminal of the gate capacitor C1 is connected to the emitter of the second switch tube Q2.

[0056] In a preferred embodiment, the first switch tube Q1 is a normally closed switch tube.

[0057] In a preferred embodiment, it also includes:

[0058] A voltage source DC, wherein a positive voltage terminal of the voltage source DC is a first voltage terminal P1, and a negative voltage terminal of the voltage source DC is a second voltage terminal P2;

[0059] A bus capacitor C2, wherein a first end of the bus capacitor C2 is connected to the first voltage terminal P1, and a second end of the bus capacitor C2 is connected to the second voltage terminal P2;

[0060] A load branch, wherein a first end of the load branch is connected to the first voltage terminal P1 , and a second end of the load branch is connected to the AC output terminal P3 .

[0061] Specifically, the switch tube driving circuit 1 of the present invention is applied to a load circuit. Figure 3 In the prior art shown, the gate capacitor C1 is a fixed value solution, and its capacitance value needs to meet the requirements under the most extreme working conditions. Therefore, the capacity of the gate capacitor C1 is too large most of the time, which increases the switching loss and temperature rise of the driving circuit and limits the performance of the switch tube Q; while the gate capacitor C1 of the present application and the utility model adopts a gate capacitor C1, which can dynamically adjust the gate-level gate capacitor C1 according to the working state of the switch tube Q, specifically the voltage change rate, to optimize the driving performance and reduce the switching loss and temperature rise.

[0062] The above description is only a preferred embodiment of the present invention and does not limit the implementation method and protection scope of the present invention. For those skilled in the art, it should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the description and illustrations of the present invention should be included in the protection scope of the present invention.

Claims

1. A switch tube drive circuit with adjustable gate capacitance, connected to a switch tube (Q), characterized in that: include, A driving chip (S1), wherein the output end of the driving chip (S1) is connected to the gate of the switching tube (Q), and the acquisition end of the driving chip (S1) is connected to the collector and emitter of the switching tube (Q), and collects a voltage waveform to obtain a voltage change rate of the switching tube (Q); A gate capacitor (C1), wherein a first end of the gate capacitor (C1) is connected to a gate of the switch tube (Q), a second end of the gate capacitor (C1) is connected to an emitter of the switch tube (Q), the driver chip (S1) outputs a capacitance control signal based on the voltage change rate, and the gate capacitor (C1) is controllably adjusted to a capacitance value corresponding to the capacitance control signal.

2. The switch tube driving circuit according to claim 1, characterized in that: The gate capacitor (C1) has a plurality of numerical gears, the voltage change rate is divided into change intervals having the same number as the numerical gears, and each change interval corresponds to one numerical gear.

3. The switch tube driving circuit according to claim 2, wherein: The capacitance value of the gate capacitor (C1) ranges from 0nF to 10nF.

4. The switch tube driving circuit according to claim 2, wherein: The voltage change rate of the switch tube (Q) ranges from 0V / us to 5000V / us.

5. The switch tube driving circuit according to claim 1, wherein: The driving chip (S1) comprises a first collecting end and a second collecting end, the first collecting end of the driving chip (S1) is connected to the collector of the switching tube (Q), and the second collecting end of the driving chip (S1) is connected to the emitter of the switching tube (Q).

6. The switch tube driving circuit according to claim 1, wherein: It also includes a driving resistor (R1), and the output end of the driving chip (S1) is connected to the gate of the switching tube (Q) through the driving resistor (R1).

7. The switch tube driving circuit according to claim 1, wherein: The switch tube (Q) is an IGBT tube.

8. A load circuit, comprising a switch branch, the switch branch comprising a first switch tube (Q1) and a second switch tube (Q2) connected between a first voltage terminal (P1) and a second voltage terminal (P2), the collector of the first switch tube (Q1) being connected to the first voltage terminal (P1), the collector of the second switch tube (Q2) being connected to the emitter of the first switch tube (Q1), the emitter of the second switch tube (Q2) being connected to the second voltage terminal (P2), the emitter of the first switch tube (Q1) being an AC output terminal (P3) of the switch branch, characterized in that: The second switch tube (Q2) is connected to the switch tube driving circuit (1) according to any one of claims 1 to 6, the output end of the driving chip (S1) is connected to the gate of the second switch tube (Q2), the acquisition end of the driving chip (S1) is connected to the collector and emitter of the second switch tube (Q2), the first end of the gate capacitor (C1) is connected to the gate of the second switch tube (Q2), and the second end of the gate capacitor (C1) is connected to the emitter of the second switch tube (Q2).

9. The load circuit according to claim 8, wherein: The first switch tube (Q1) is a normally closed switch tube.

10. The load circuit according to claim 8, wherein: Also includes, a voltage source (DC), wherein the forward voltage terminal of the voltage source (DC) is the first voltage terminal (P1), and the reverse voltage terminal of the voltage source (DC) is the second voltage terminal (P2); a bus capacitor (C2), wherein a first end of the bus capacitor (C2) is connected to the first voltage end (P1), and a second end of the bus capacitor (C2) is connected to the second voltage end (P2); A load branch, wherein a first end of the load branch is connected to the first voltage end (P1), and a second end of the load branch is connected to the AC output end (P3).

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