Kelvin source tandem type active gate drive circuit

Abstract

The invention discloses a Kelvin source series connection type active gate drive circuit, and belongs to the technical field of power generation, power transformation or power distribution. The circuit is composed of a signal conditioning circuit, a bidirectional follower circuit, a feedback capacitor, a gate driver and a power supply circuit thereof, and a driving resistor. The signal conditioning circuit is provided with two input ports and two output ports, the two input ports are respectively connected with a power source electrode and a feedback capacitor of the switching device, and the two output ports are connected with an input port of the bidirectional follower circuit. The bidirectional follower circuit is provided with two input ports and a modulation output port, and the modulation output port is connected with a reference point of the gate driver and the power supply circuit of the gate driver. The output port of the gate driver and power supply circuit is connected with the gate of the switching device after being connected with the driving resistor. On the basis of common gate drive, low-delay and real-time feedback closed-loop active gate drive is realized by changing a circuit connection structure and utilizing reference point voltage modulation, and the purpose of reducing voltage and current overshoot of a power device is achieved.

Description

Technical Field

[0001] The present invention relates to power electronics application technology, and discloses a kind of driving circuit for switching devices, in particular to a Kelvin source series type active gate driving circuit, belonging to the technical field of power generation, power transformation or power distribution. Background Art

[0002] In recent years, with the development of power electronics technology, the requirements of converters for semiconductor device driving circuits have been correspondingly improved. The high-speed characteristics of high-performance semiconductor switching devices make the problems of voltage and current overshoot more obvious. The traditional gate driving structure composed of a gate driving chip and a resistor can adjust the switching speed of the switching device to a certain extent, but limited by the waveform spontaneously generated during the switching instant of the device, the slopes of voltage and current follow a change pattern of slow first and then fast, and its adjustment ability needs to make a trade-off between voltage and current overshoot and switching loss, wasting the performance of the device and reducing the overall efficiency.

[0003] Active gate driving controls the driving signal actively, so that the characteristics during the switching instant of the device deviate from the waveform spontaneously generated under the traditional gate driving, and the slopes of voltage and current are controlled to achieve the purpose of reducing voltage and current overshoot. The existing active gate driving circuits can be divided into gate series type, gate parallel type and controllable source type active gate driving according to the circuit structure. Among them, the gate series type and gate parallel type active gate driving circuits are composed of a conventional gate driving part and an active modulation part. In the gate series type active gate driving circuit, the active modulation part is connected in series between the gate of the switching device and the conventional gate driving structure; in the gate parallel type active gate driving circuit, the active modulation part is connected in parallel between the gate and the source of the switching device. The controllable source type active gate driving directly uses operational amplifiers, linear power amplification circuits, etc. to realize a controllable voltage source or a controllable current source as the gate driving.

[0004] For the gate series type active gate driving, since its active modulation part is entirely on the gate line, the active modulation part has a common-mode voltage of the gate voltage waveform during the gate driving operation, and the current and voltage feedback signals cannot be directly transmitted to the active modulation part, and a level shift circuit is required to enable the feedback signals to be transmitted to the active modulation part. The level shift circuit will introduce delay, affecting the real-time feedback operation. This type of active gate driving generally adopts fixed timing control to avoid the delay problem.

[0005] For the gate parallel type active gate driving, since its working principle is to bypass a part of the gate driving current, it will inevitably generate a circulating current between the gate driving and the active modulation part, resulting in an increase in gate driving loss and an improvement in the requirements for the gate driving power supply.

[0006] For controllable-source type active gate drive, the operational amplifiers and linear power amplification circuits used are relatively complex, and the overall signal link from the gate drive signal to the gate drive output is relatively long. In addition to having a high delay, it is also vulnerable to interference. Similarly, due to its complex structure, this type of active gate drive has high requirements for the power, ripple, etc. of the gate drive power supply.

[0007] As drive methods such as optocouplers and isolated drive chips gradually replace pulse transformers, more reliable and better isolated gate drives are realized. Correspondingly, due to the isolation requirements of the switch device drive itself, the isolated power supply circuit of the gate drive has become increasingly mature. The gate drive and its power supply can achieve an extremely small common-mode capacitance, realizing an almost completely isolated effect of the signal and power supply, which makes some new gate drive circuit structures possible. Summary of the Invention

[0008] The invention object of the present invention is to overcome the deficiencies of the above background technology, and provide a Kelvin source series type active gate drive circuit. By changing the connection method of the active modulation part circuit with the gate drive and its power supply circuit, while realizing the basic functions of the gate series type active gate drive, voltage and current direct feedback are realized, making high-speed and real-time closed-loop control possible, enhancing the adaptability of the active gate drive to load changes, solving the technical problems of the complex structure and poor multi-load adaptability of the traditional active gate drive, and achieving the invention object of the flexible and reliable application of the active gate drive.

[0009] The present invention adopts the following technical solutions to achieve the above invention object:

[0010] Kelvin source series active gate drive circuit, comprising: a signal conditioning circuit, a bidirectional follower circuit, a feedback capacitor, a gate drive and its power supply circuit, and a drive resistor; the signal conditioning circuit has a voltage feedback input port, a current feedback input port, a first signal conditioning output port, and a second signal conditioning output port, the current feedback input port is connected to the power source electrode of the switching device, the first signal conditioning output port outputs a voltage response signal after conditioning the source current sampling signal and the drain voltage sampling signal of the switching device during the turn-off process of the switching device, and the second signal conditioning output port outputs a voltage response signal after conditioning the source current sampling signal and the drain voltage sampling signal of the switching device during the turn-on process of the switching device; two input ports of the bidirectional follower circuit are respectively connected to the first signal conditioning output port and the second signal conditioning output port, and after following the voltage response signal of the first signal conditioning output port or the voltage response signal of the second signal conditioning output port, outputs a floating ground port voltage; one pole of the feedback capacitor is connected to the drain of the switching device, and the other pole of the feedback capacitor is connected to the voltage feedback input port; the reference point of the gate drive and its power supply circuit is connected to the floating ground port voltage; one end of the drive resistor is connected to the output end of the gate drive and its power supply circuit, and the other end of the drive resistor is connected to the gate of the switching device.

[0011] As a further optimization scheme of the Kelvin source series active gate drive circuit, the signal conditioning circuit comprises: a first protection diode, a second protection diode, a first resistor network, and a second resistor network; the anode of the first protection diode is connected to the voltage feedback input port; the cathode of the second protection diode is connected to the voltage feedback input port; the first input end of the first resistor network is connected to the cathode of the first protection diode, the second input end of the first resistor network is connected to the current feedback input port, and outputs a voltage response signal after conditioning the source current sampling signal and the drain voltage sampling signal of the switching device during the turn-off process of the switching device to the first conditioning signal output port; the first input end of the second resistor network is connected to the anode of the second protection diode, the second input end of the second resistor network is connected to the current feedback input port, and outputs a voltage response signal after conditioning the source current sampling signal and the drain voltage sampling signal of the switching device during the turn-on process of the switching device to the second signal conditioning output port.

[0012] As a further optimization scheme of the Kelvin source series active gate drive circuit, the circuit structures of the first resistor network and the second resistor network are the same;

[0013] The first resistor network includes: a first protection resistor, a first conditioning resistor as the a-conditioning resistor, and a second conditioning resistor as the b-conditioning resistor; one end of the first protection resistor serves as the first input terminal of the first resistor network and is connected to the cathode of the first protection diode, and the other end of the first protection resistor is connected to the first signal conditioning output port; one end of the first conditioning resistor serves as the second input terminal of the first resistor network and is connected to the current feedback input port, and the other end of the first conditioning resistor is connected to the first signal conditioning output port; one end of the second conditioning resistor is connected to the first signal conditioning output port, and the other end of the second conditioning resistor is connected to the signal conditioning circuit reference point, and the signal conditioning circuit reference point is connected to the Kelvin source of the switching device;

[0014] The second resistor network includes: a second protection resistor, a third conditioning resistor as the a-conditioning resistor, and a fourth conditioning resistor as the b-conditioning resistor; one end of the second protection resistor serves as the first input terminal of the second resistor network and is connected to the anode of the second protection diode, and the other end of the second protection resistor is connected to the second signal conditioning output port; one end of the third conditioning resistor serves as the second input terminal of the second resistor network and is connected to the current feedback input port, and the other end of the third conditioning resistor is connected to the second signal conditioning output port; one end of the fourth conditioning resistor is connected to the second signal conditioning output port, and the other end of the fourth conditioning resistor is connected to the signal conditioning circuit reference point, and the signal conditioning circuit reference point is connected to the Kelvin source of the switching device.

[0015] As a further optimized solution of the Kelvin source series active gate drive circuit, the circuit structures of the first resistor network and the second resistor network are the same;

[0016] The first resistor network includes: a first protection resistor and a first resistor; one end of the first protection resistor serves as the first input terminal of the first resistor network and is connected to the cathode of the first protection diode, and the other end of the first protection resistor is connected to the first signal conditioning output port; one end of the first resistor is connected to the first signal conditioning output port, and the other end of the first resistor is connected to the signal conditioning circuit reference point, and the signal conditioning circuit reference point is connected to the power source of the switching device;

[0017] The first resistor network includes: a second protection resistor and a second resistor; one end of the second protection resistor serves as the first input terminal of the second resistor network and is connected to the anode of the second protection diode, and the other end of the second protection resistor is connected to the second signal conditioning output port; one end of the second resistor is connected to the second signal conditioning output port, and the other end of the second resistor is connected to the signal conditioning circuit reference point, and the signal conditioning circuit reference point is connected to the power source of the switching device.

[0018] As a further optimized solution for the Kelvin source series active gate drive circuit, the bidirectional follower circuit includes: an NPN transistor, a PNP transistor, a first Schottky diode, and a second Schottky diode; the emitter of the NPN transistor is connected to the reference point of the signal conditioning circuit, and the base of the NPN transistor is connected to the first conditioning signal output port; the emitter of the PNP transistor is connected to the reference point of the signal conditioning circuit, and the base of the PNP transistor is connected to the second conditioning signal output port; the cathode of the first Schottky diode is connected to the collector of the NPN transistor; the anode of the second Schottky diode is connected to the collector of the PNP transistor, and the cathode of the second Schottky diode is connected to the anode of the first Schottky diode and then used as the output terminal of the bidirectional follower circuit.

[0019] As a further optimized solution for the Kelvin source series active gate drive circuit, the drive resistor is a circuit structure including a single resistor or a circuit structure including an on-resistance and an off-resistance; when the drive circuit is a circuit structure including an on-resistance and an off-resistance, two resistors are respectively connected through a gate drive with separate push-pull outputs and its power supply circuit, or, through a gate drive circuit with a single output and its power supply circuit, the on-resistance and the off-resistance are respectively connected through two diodes with opposite directions.

[0020] As a further optimized solution for the Kelvin source series active gate drive circuit, the drive circuit is used for gate drive of voltage-driven switching devices including but not limited to MOSFET and IGBT.

[0021] The present invention adopts the above technical solutions and has the following beneficial effects:

[0022] (1) For the Kelvin source series active gate drive circuit proposed by the present invention, through the negative feedback loop formed by the signal conditioning circuit, the bidirectional follower circuit and the traditional gate drive, direct feedback of voltage and current is realized, ensuring its low switching delay and high switching speed. With high-speed and real-time closed-loop control, the adaptability of the active gate drive to load changes is enhanced.

[0023] (2) For the Kelvin source series active gate drive circuit proposed by the present invention, through the signal conditioning circuit, voltage and current hybrid closed-loop control is realized, which can reduce the voltage and current overshoot of the switching device. Compared with separate voltage or current closed-loop control, it has a better overshoot suppression effect, and at the same time has higher flexibility and expansion ability. Compared with the traditional gate drive with the same overshoot performance, it has lower switching losses.

[0024] (3) The structure of the Kelvin source series active gate drive circuit proposed by the present invention is based on the traditional gate drive, with a simple structure and is easy to replace from the traditional gate drive to the proposed active gate drive.

[0025] (4) The Kelvin source - series active gate - driving circuit proposed by the present invention can be reduced to a traditional gate - driving circuit by short - circuiting the active modulation part through a bypass switch, and has high robustness in the face of a scenario where the active modulation part fails. Brief Description of the Drawings

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, for those skilled in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0027] Figure 1 It is the basic circuit structure of the Kelvin source - series active gate - driving circuit.

[0028] Figure 2 It is the signal conditioning circuit structure for a switching device with a Kelvin source package.

[0029] Figure 3 It is the signal conditioning circuit structure for a switching device without a Kelvin source package.

[0030] Figure 4 It is the circuit structure of the bidirectional follower circuit, gate drive, and its power - supply circuit.

[0031] Figure 5 It is the switching waveform diagram of the proposed active gate - driving under an 800V, 20A load.

[0032] Figure 6 It is the switching waveform diagram of the traditional gate - driving under an 800V, 20A load.

[0033] Figure 7 It is the adjusted switching waveform diagram of the traditional gate - driving under an 800V, 20A load.

[0034] Figure 8 It is the waveform diagram of the voltage overshoot of the proposed active gate - driving under different load conditions.

[0035] Figure 9 It is the waveform diagram of the current overshoot of the proposed active gate - driving under different load conditions.

[0036] Explanation of the reference numerals in the figures: C fb , feedback capacitor, R g , driving resistor, R s1 , first protection resistor, R s2 , second protection resistor, R a1 , first conditioning resistor, R b1 , second conditioning resistor, R a2 , third conditioning resistor, Rb2 , the fourth conditioning resistor, R 1 , the first resistor, R 2 , the second resistor, D s1 , the first protection diode, D s2 , the second protection diode, D 1 , the first Schottky diode, D 2 , the second Schottky diode, Q 1 , the NPN transistor, Q 2 , the PNP transistor, v 1 , the first conditioning signal output port, v 2 , the second conditioning signal output port. Detailed implementation mode

[0037] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present invention.

[0038] In a specific embodiment, a Kelvin source series active gate drive circuit applicable to voltage-driven switching devices such as MOSFET and IGBT is as Figure 1 shown, and is composed of a signal conditioning circuit, a bidirectional follower circuit, a feedback capacitor, a gate drive and its power supply circuit, and a drive resistor.

[0039] The signal conditioning circuit has a voltage feedback input port, a current feedback input port, and two conditioning signal output ports. The current feedback input port is connected to the power source electrode of the switching device, and the two output ports are connected to the input ports of the bidirectional follower circuit; the feedback capacitor is connected between the drain electrode of the switching device and the voltage feedback input port of the signal conditioning circuit; the bidirectional follower circuit has two input ports and a modulation output port, and the modulation output port is connected to the reference point of the gate drive and its power supply circuit; after the output port of the gate drive and its power supply circuit is connected to the drive resistor, it is connected to the gate electrode of the switching device.

[0040] As Figure 2 shown, for a switching device with a Kelvin source package, the reference point of the signal conditioning circuit is connected to the Kelvin source of the switching device, and the Kelvin source series active gate drive circuit has the ability of voltage and current slope control. The signal conditioning circuit is composed of a first resistor network and a second resistor network with the same structure, and the first protection diode D s1 , the second protection diode D s2 constitute. The first resistor network is composed of the resistor first protection resistor R s1 , the first conditioning resistor R a1, the second conditioning resistor R b1 The voltage-dividing resistor network composed of s2 , the third conditioning resistor R a2 , the fourth conditioning resistor R b2 The second conditioning resistor R b1 , the fourth conditioning resistor R b2 One end is commonly connected to the reference point of the signal conditioning circuit. The second conditioning resistor R b1 , the fourth conditioning resistor R b2 The other ends are respectively connected to the first conditioning signal output port v 1 , the second conditioning signal output port v 2 ; The first conditioning resistor R a1 , the third conditioning resistor R a2 One end is commonly connected to the current feedback input port. The first conditioning resistor R a1 , the third conditioning resistor R a2 The other ends are respectively connected to the first conditioning signal output port v 1 , the second conditioning signal output port v 2 ; The first protection resistor R s1 , the second protection resistor R s2 One end is respectively connected to the cathode of the first protection diode D s1 , the anode of the second protection diode D s2 ; The first protection resistor R s1 , the second protection resistor R s2 The other ends are respectively connected to the first conditioning signal output port v 1 , the second conditioning signal output port v 2 ; The anode of the first protection diode D s1 , the cathode of the second protection diode D s2 Are commonly connected to one plate of the feedback capacitor C fb . The other plate of the feedback capacitor C fb Is connected to the drain of the switching device. The circuit connection method of the second resistor network is the same as that of the first resistor network, which will not be elaborated in this application.

[0041] For a switching device without a Kelvin source package, from the Figure 2 Generalized design of the signal conditioning circuit shown, obtain the improved signal conditioning circuit shown in Figure 3 . The reference point of the signal conditioning circuit is connected to the power source of the switching device. The Kelvin source series active gate drive circuit has the ability to control the voltage slope. The first conditioning resistor R a1 , the second conditioning resistor R b1 Are combined into the first resistor R 1 , the third conditioning resistor R a2 , the fourth conditioning resistor R b2Combined into the second resistor R 2 , the first resistor R 1 , the second resistor R 2 One end is connected to the reference point, the first resistor R 1 , the second resistor R 2 The other end is connected to the first conditioning signal output port v 1 , the second conditioning signal output port v 2 .

[0042] like Figure 4 As shown, the bidirectional follower circuit consists of an NPN transistor Q 1 、PNP transistor Q 2 、The first Schottky diode D 1 , the second Schottky diode D 2 Among them, the NPN transistor Q 1 、PNP transistor Q 2 The emitters of the NPN transistor Q are connected together to the reference point of the signal conditioning circuit. 1 、PNP transistor Q 2 The collector of the first Schottky diode D 1 Cathode, second Schottky diode D 2 Anode, NPN transistor Q 1 、PNP transistor Q 2 The bases of the first conditioned signal output ports are connected to 1 , the second conditioning signal output port v 2 , the first Schottky diode D 1 Anode, second Schottky diode D 2 The cathode is connected to the reference point of the gate drive and its power supply circuit, that is, the floating port v a . Driving resistance R g Connected between the output end of the gate drive and its power supply circuit and the gate of the switching device.

[0043] The gate drive and its power supply circuit adopt isolated signal transmission and isolated power supply. Signal transmission is not affected by the relative voltage between the gate drive reference point voltage and the signal input side, and power supply is not affected by the relative voltage between the gate drive reference point voltage and the power input side, ensuring that the active gate drive can work normally.

[0044] The driving resistor can adopt a single resistor or two resistors to bear the circuit structure of opening and closing the resistor respectively. If two resistors are used, a gate driver chip with separate push and pull outputs can be used to connect the two resistors, or a gate driver chip with a single output can be used with two diodes in opposite directions to achieve the effect of separating the two resistors.

[0045] The signal conditioning circuit is composed of two sets of resistor networks with the same structure. Taking one of them as an example, the working principle is as follows:

[0046] The signal conditioning circuit responds to di / dt to generate a current feedback signal, which is generated by the source parasitic inductance L of the switch device package. s Generally, the source inductance of the TO-247-4 package is about 10 nH, which can generate a large enough current feedback signal. When the current flowing through the source of the switch device changes, the voltage across the source parasitic inductance L s can be expressed as:

[0047]

[0048] The signal conditioning circuit responds to dv / dt to generate a voltage feedback signal, which is generated by the feedback capacitor C. fb When the drain voltage of the switch device changes, the voltage feedback signal generated by the current flowing through the feedback capacitor C fb acting on the first resistor network can be expressed as:

[0049]

[0050] R s1 is the first protection resistor, with a small value and hardly affecting the feedback signal. After being conditioned by the first conditioning resistor R a1 , the second conditioning resistor R b1 , the conditioned feedback signal is output to the first conditioning signal output port v 1 . The signal output from the first conditioning signal output port is:

[0051]

[0052] The feedback signals corresponding to the first conditioning resistor R a1 and the second conditioning resistor R b1 are output to the first conditioning signal output port v 1 . The feedback signals corresponding to the third conditioning resistor R a2 and the fourth conditioning resistor R b2 are output to the second conditioning signal output port v 2 . The first protection diode D s1 and the second protection diode D s2 ensure that the first conditioning signal output port v 1 responds only to the voltage signal during the turn-off process of the switch device, and the second conditioning signal output port v 2 responds only to the voltage signal during the turn-on process of the switch device.

[0053] When the gate drive and its power supply circuit receive the turn-on signal, its output voltage is from the turn-off voltage v Dr(off)Becomes the turn-on voltage v Dr(on) , the gate drive current flows to the gate of the switching device. At this time, the second Schottky diode D 2 conducts, and the first Schottky diode D 1 is cut off. The PNP transistor Q 2 operates in the mode of a follower. The emitter voltage of the PNP transistor Q 2 and the base voltage maintain a forward voltage drop of a PN junction, plus the voltage drop of the second Schottky diode D 2 , the voltage drop of the gate drive, etc., there is a relatively constant voltage drop V Drop , about 1.5V. The voltage at the output port of the gate drive and its power supply circuit is:

[0054] v o = v 2 + v Dr(off) + V Drop (4)

[0055] Similarly, when the gate drive and its power supply circuit receive a turn-off signal, the first Schottky diode D 1 conducts, and the first NPN transistor Q 1 operates in the mode of a follower. The voltage at the output port of the gate drive and its power supply circuit is:

[0056] v o = v 1 + v Dr(on) - V Drop (5)

[0057] For a switching device in the switching transient state, its gate voltage is approximately the Miller plateau voltage V mil . According to the parameters of the device such as C iss , C rss , g m , etc., according to Kirchhoff's principle, the following equation about the gate current can be listed:

[0058]

[0059] According to the above equations, the voltage and current change rates of the device when the proposed active gate drive works normally can be deduced. Among them, the gate drive resistance R g According to the actual usage situation, the form of independent drive resistances for turn-on and turn-off is usually adopted, which are R g(on) , R g(off) .

[0060]

[0061] Equation (7) represents the effect of the active gate drive in closed-loop operation. By adjusting various parameters, the rate of change of the voltage and current of the switching device can be adjusted to achieve the purpose of reducing voltage and current overshoots.

[0062] To verify the feasibility of this solution, a double-pulse test platform was built. The switching device selected was C3M0075120K (1200V / 75mΩ), the test bus voltage was 800V, and the test current was 20A. The test included three cases, namely traditional gate drive, traditional gate drive adjusted to have the same overshoot as the active gate drive, and the proposed active gate drive. The experimental waveforms are as Figure 5 、 Figure 6 、 Figure 7 shown.

[0063] The experimental results are compared in Table 1. It can be found that due to the application of the proposed active gate drive, the voltage and current overshoots are reduced. And because of the application of real-time closed-loop feedback, the turn-on and turn-off delays are not significantly increased, and the switching losses are significantly reduced compared with the traditional gate drive with reduced overshoot after adjustment.

[0064] Table 1 Comparison of experimental results

[0065] Parameter Conventional gate drive Conventional gate drive (slow) Active gate drive Turn-on delay 25 ns 44 ns 27 ns Turn-off delay 42 ns 89 ns 55 ns Turn-on loss 228.8 μJ 457.4 μJ 383.8 μJ Turn-off loss 136.5 μJ 319.0 μJ 230.0 μJ Voltage overshoot 1070V 1000V 990V Current overshoot 33A 27A 27A

[0066] To verify the closed-loop control effect of the proposed active gate drive, the experiment further verified the operating state of the proposed active gate drive under different load conditions. The experimental results are as Figure 8 、 Figure 9 shown. It can be considered that the proposed active gate drive shows stable effects under different load conditions. Under different load conditions, it can be seen from the result waveforms that the rise and fall times of the device current and voltage change, but their voltage and current slopes and overshoots are constant, indicating that the proposed active gate drive can well adapt to these changes, proving the effectiveness of the real-time closed-loop control of voltage and current.

[0067] In the description of this specification, the descriptions referring to terms such as "one embodiment", "example", "specific example", etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0068] The foregoing has shown and described the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and the descriptions in the above embodiments and the specification are only used to illustrate the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of protection claimed.

Claims

1. A Kelvin source series active gate drive circuit, characterized in that: include: A signal conditioning circuit, comprising a voltage feedback input port, a current feedback input port, a first signal conditioning output port and a second signal conditioning output port, wherein the current feedback input port is connected to a power source of a switching device, the first signal conditioning output port outputs a voltage response signal after conditioning a source current sampling signal and a drain voltage sampling signal of the switching device during a switching-off process of the switching device, and the second signal conditioning output port outputs a voltage response signal after conditioning a source current sampling signal and a drain voltage sampling signal of the switching device during a switching-on process of the switching device; A bidirectional follower circuit, wherein two input ports of the bidirectional follower circuit are respectively connected to the first signal conditioning output port and the second signal conditioning output port, and outputs a floating port voltage after following a voltage response signal of the first signal conditioning output port or a voltage response signal of the second signal conditioning output port; A feedback capacitor, one electrode of which is connected to the drain of the switching device, and the other electrode of which is connected to the voltage feedback input port; A gate drive circuit and a power supply circuit thereof, wherein a reference point thereof is connected to the floating port voltage; and A driving resistor, one end of which is connected to the gate drive and the output end of the power supply circuit, and the other end of which is connected to the gate of the switching device.

2. The Kelvin source series active gate drive circuit according to claim 1, characterized in that: The signal conditioning circuit comprises: A first protection diode, an anode of which is connected to the voltage feedback input port; A second protection diode, a cathode of which is connected to the voltage feedback input port; a first resistor network, whose first input end is connected to the cathode of the first protection diode, and whose second input end is connected to the current feedback input port, outputs a voltage response signal after conditioning the source current sampling signal and the drain voltage sampling signal of the switching device to the first conditioned signal output port during the shutdown process of the switching device; and, A second resistor network, whose first input end is connected to the anode of the second protection diode and whose second input end is connected to the current feedback input port, outputs a voltage response signal after conditioning the source current sampling signal and the drain voltage sampling signal of the switching device to the second signal conditioning output port during the switching device opening process.

3. The Kelvin source series active gate drive circuit according to claim 2, characterized in that: The first resistor network and the second resistor network have the same circuit structure, and both include: Protection resistor ( R s1 , R s2 ), one end of which is connected to the cathode of the first protection diode or the anode of the second protection diode as the first input end of the first / second resistance network, and the other end of which is connected to the first / second signal conditioning output port; a Conditioning resistor ( R a1 , R a2 ), one end of which is connected to the current feedback input port as the second input end of the first / second resistor network, and the other end of which is connected to the first / second signal conditioning output port; b Conditioning resistor ( R b1 , R b2 ), one end of which is connected to the first / second signal conditioning output port, and the other end of which is connected to the signal conditioning circuit reference point, and the signal conditioning circuit reference point is connected to the Kelvin source of the switching device.

4. The Kelvin source series active gate drive circuit according to claim 2, characterized in that: The first resistor network and the second resistor network have the same circuit structure, and both include: Protection resistor ( R s1 , R s2 ), one end of which is connected to the cathode of the first protection diode or the anode of the second protection diode as the first input end of the first / second resistance network, and the other end of which is connected to the first / second signal conditioning output port; and, Conditioning resistor ( R 1, R 2), one end of which is connected to the first / second signal conditioning output port, and the other end of which is connected to the signal conditioning circuit reference point, and the signal conditioning circuit reference point is connected to the power source of the switching device.

5. The Kelvin source series active gate drive circuit according to claim 3 or 4, characterized in that: The bidirectional follower circuit comprises: NPN transistor ( Q 1), its emitter is connected to the signal conditioning circuit reference point, and its base is connected to the first conditioning signal output port; PNP transistor ( Q 2), its emitter is connected to the signal conditioning circuit reference point, and its base is connected to the second conditioning signal output port; The first Schottky diode ( D 1), its cathode is connected to the NPN transistor ( Q 1) the collector; and, The second Schottky diode ( D 2) Its anode is connected to the PNP transistor ( Q 2) The collector and cathode of the first Schottky diode ( D 1) The anode is connected as the output terminal of the bidirectional follower circuit.

6. The Kelvin source series active gate drive circuit according to claim 5, characterized in that: The driving resistor is a circuit structure including a single resistor or a circuit structure including an on-resistance and an off-resistance; when the driving circuit is a circuit structure including an on-resistance and an off-resistance, the two resistors are respectively connected through a gate drive with separate push and pull outputs and a power supply circuit thereof, or, the on-resistance and the off-resistance are respectively connected through two diodes in opposite directions through a gate drive circuit with a single output and a power supply circuit thereof.

7. The Kelvin source series active gate drive circuit according to claim 5, characterized in that: Used for gate driving of voltage-driven switching devices including but not limited to MOSFET and IGBT.

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