High-voltage pulse leading edge steepening circuit based on H bridge

Abstract

The invention discloses a high-voltage pulse leading edge steepening circuit based on an H bridge, and belongs to the field of high-voltage electric field pulse ablation, the high-voltage pulse leading edge steepening circuit comprises a switch tube Q1, a switch tube Q2, a switch tube Q3, a switch tube Q4 and a load RL, the collector electrode of the switch tube Q1 is connected with a power supply VH; the emitter of the switch tube Q1 is connected with the collector of the switch tube Q2; the collector electrode of the switching tube Q4 is connected with the power supply VH; the emitter of the switch tube Q4 is connected with the collector of the switch tube Q3; the emitting electrode of the switch tube Q2 and the emitting electrode of the switch tube Q3 are grounded; one end of the load RL is connected with the emitter of the switch tube Q1, and the other end of the load RL is connected with the emitter of the switch tube Q4. Compared with a Marx circuit, the H-bridge circuit has the advantages of relatively simple control, high repetition frequency, small harmonic distortion and the like.

Description

Technical Field

[0001] The present invention relates to the field of high-voltage electric field pulse ablation, and specifically to a high-voltage pulse front steepening circuit based on an H-bridge. Background Art

[0002] High-voltage electric field pulse ablation is to apply microsecond- or even nanosecond-level high-voltage electric pulses to tissues, causing irreversible electroporation of cells, thereby leading to cell apoptosis or necrosis, achieving the purpose of ablating tissues. Compared with traditional ablation techniques such as radiofrequency ablation and cryoablation, this technology has the advantages of better tissue selectivity, higher safety, higher ablation efficiency, more persistent effectiveness, and less impact on physiological functions. Moreover, research shows that nanosecond-level pulses have weaker thermal effects, lower risk of muscle tremors, and milder inflammatory responses compared with microsecond-level pulses, and patients do not even need general anesthesia, only local anesthesia is required.

[0003] High-voltage electric field pulse ablation requires the ablation device to be able to generate nanosecond pulses. However, limited by the switching speed of high-voltage switching tubes such as IGBTs or SIC-MOSFETs, the pulse front will be relatively slow. The generated nanosecond pulses are not square waves but more similar to spikes, which are likely to cause problems such as relatively complex control and large harmonic distortion. Summary of the Invention

[0004] Regarding the above problems existing in the prior art, the purpose of the present invention is to provide a high-voltage pulse front steepening circuit based on an H-bridge to solve the problems raised in the above background art.

[0005] To achieve the above purpose, the present invention provides the following technical solutions:

[0006] The high-voltage pulse front steepening circuit based on an H-bridge includes switching tubes Q1, Q2, Q3, Q4, and a load RL. The collector of switching tube Q1 is connected to the power supply VH;

[0007] The emitter of switching tube Q1 is connected to the collector of switching tube Q2;

[0008] The collector of switching tube Q4 is connected to the power supply VH;

[0009] The emitter of switching tube Q4 is connected to the collector of switching tube Q3;

[0010] The emitters of switching tubes Q2 and Q3 are both grounded;

[0011] One end of the load RL is connected to the emitter of switching tube Q1, and the other end of the load RL is connected to the emitter of switching tube Q4.

[0012] As a further aspect of the present invention: the base of the switching transistor Q1 and the base of the switching transistor Q3 are connected to an external control signal; the base of the switching transistor Q2 and the base of the switching transistor Q4 are connected to another external control signal.

[0013] As a further aspect of the present invention: the emitter of the switching transistor Q1 is connected to the negative pole of the power supply VDC1; the positive pole of the power supply VDC1 is connected to one end of the current-limiting resistor Rd1, the other end of the current-limiting resistor Rd1 is connected to the positive pole of the steepening diode D1, and the negative pole of the steepening diode D1 is connected to the emitter of the switching transistor Q1.

[0014] As a further aspect of the present invention: the emitter of the switching transistor Q4 is connected to the negative pole of the power supply VDC2; the positive pole of the power supply VDC2 is connected to one end of the current-limiting resistor Rd2, the other end of the current-limiting resistor Rd2 is connected to the positive pole of the steepening diode D2, and the negative pole of the steepening diode D2 is connected to the emitter of the switching transistor Q4.

[0015] As a further aspect of the present invention: the positive pole of the steepening diode D1 is connected to one end of the buffer capacitor Cd, and the other end of the buffer capacitor Cd is connected to the positive pole of the steepening diode D2.

[0016] As a further aspect of the present invention: the switching transistors Q1, Q2, Q3, and Q4 are IGBTs or SIC-MOSFETs.

[0017] As a further aspect of the present invention: the steepening diode D1 and the steepening diode D2 are both composed of multiple groups of diodes connected in parallel.

[0018] As a further aspect of the present invention: the steepening diode D1 or the steepening diode D2 includes 6 groups of diode groups connected in parallel, and each diode group is composed of 3 two diodes connected in series.

[0019] As a further aspect of the present invention: the buffer capacitor Cd is composed of two 2000V / 1uF capacitors connected in series.

[0020] As a further aspect of the present invention: the current-limiting resistor Rd1 or the current-limiting resistor Rd2 is composed of two 50-ohm resistors connected in parallel.

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] This circuit is implemented based on the reverse recovery characteristics of diodes, and the steepening effect depends on the reverse recovery current of the steepening diodes. The required steepening effect can be achieved by adjusting the voltages of VDC1 and VDC2, the resistances of the current-limiting resistors Rd1 and Rd2, the number of parallel-connected steepening diodes D1 and D2, etc. Compared with the Marx circuit solution, the H-bridge circuit has the advantages of relatively simple control, high repetition frequency, and low harmonic distortion. Description of the Drawings

[0023] Figure 1 Schematic diagram of the circuit structure of the high-voltage pulse front steepening circuit based on the H-bridge disclosed in the embodiment.

[0024] Figure 2 Further schematic diagram of the circuit structure of the high-voltage pulse front steepening circuit based on the H-bridge disclosed in the embodiment.

[0025] Figure 3 Waveform diagram before steepening of the existing circuit.

[0026] Figure 4 Waveform diagram after steepening of the high-voltage pulse front steepening circuit based on the H-bridge disclosed in the embodiment. Detailed Embodiments

[0027] Next, the technical solutions in the embodiments 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 of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0028] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "installed", "provided with", "connected", and "connected" should be understood in a broad sense; for example, it can be a fixed connection, a detachable connection, or an integral connection, it can be a mechanical connection, an electrical connection, a direct connection, or an indirect connection through an intermediate medium, and it can be the internal communication of two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0029] Embodiment 1. Please refer to Figure 1 , the high-voltage pulse front steepening circuit based on the H-bridge includes a switching transistor Q1, a switching transistor Q2, a switching transistor Q3, a switching transistor Q4, and a load RL. The collector of the switching transistor Q1 is connected to the power supply VH;

[0030] The emitter of the switching transistor Q1 is connected to the collector of the switching transistor Q2;

[0031] The collector of switching transistor Q4 is connected to the power supply VH;

[0032] The emitter of switching transistor Q4 is connected to the collector of switching transistor Q3;

[0033] The emitters of switching transistors Q2 and Q3 are both grounded;

[0034] One end of the load RL is connected to the emitter of switching transistor Q1, and the other end of the load RL is connected to the emitter of switching transistor Q4.

[0035] The bases of switching transistors Q1 and Q3 are connected to an external control signal; the bases of switching transistors Q2 and Q4 are connected to another external control signal; during operation, the on / off states of switching transistors Q1, Q2, Q3, and Q4 are controlled by the external control signal at any time.

[0036] The switching transistors Q1, Q2, Q3, and Q4 are IGBTs or SIC-MOSFETs.

[0037] When switching transistors Q1 and Q3 are turned on and switching transistors Q2 and Q4 are turned off, a positive pulse is generated across the load RL; when switching transistors Q2 and Q4 are turned on and switching transistors Q1 and Q3 are turned off, a negative pulse is generated across the load RL.

[0038] Embodiment 2. Please refer to Figure 2 , a high-voltage pulse front-edge steepening circuit based on an H-bridge, including switching transistors Q1, Q2, Q3, Q4, load RL, steepening diodes D1, D2, buffer capacitor Cd, current-limiting resistors Rd1, Rd2, power supplies VDC1 and VDC2;

[0039] The collector of the switching transistor Q1 is connected to the power supply VH;

[0040] The emitter of switching transistor Q1 is connected to the collector of switching transistor Q2;

[0041] The collector of switching transistor Q4 is connected to the power supply VH;

[0042] The emitter of switching transistor Q4 is connected to the collector of switching transistor Q3;

[0043] The emitters of switching transistors Q2 and Q3 are both grounded;

[0044] One end of the load RL is connected to the emitter of switching transistor Q1, and the other end of the load RL is connected to the emitter of switching transistor Q4.

[0045] The base of switching transistor Q1 and the base of switching transistor Q3 are connected to an external control signal; the base of switching transistor Q2 and the base of switching transistor Q4 are connected to another external control signal; during operation, the on / off states of switching transistors Q1, Q2, Q3, and Q4 are controlled at any time through the external control signal.

[0046] The negative pole of power supply VDC1 is connected to the emitter of switching transistor Q1; the positive pole of power supply VDC1 is connected to one end of current-limiting resistor Rd1, the other end of current-limiting resistor Rd1 is connected to the positive pole of steepening diode D1, and the negative pole of steepening diode D1 is connected to the emitter of switching transistor Q1;

[0047] The negative pole of power supply VDC2 is connected to the emitter of switching transistor Q4; the positive pole of power supply VDC2 is connected to one end of current-limiting resistor Rd2, the other end of current-limiting resistor Rd2 is connected to the positive pole of steepening diode D2, and the negative pole of steepening diode D2 is connected to the emitter of switching transistor Q4;

[0048] One end of buffer capacitor Cd is connected to the positive pole of steepening diode D1, and the other end of buffer capacitor Cd is connected to the positive pole of steepening diode D2;

[0049] Buffer capacitor Cd can absorb or release energy to cope with sudden voltage fluctuations. When the voltage suddenly increases, the buffer capacitor will store the excess energy; when the voltage decreases, it will release the stored energy, thus maintaining the voltage stability.

[0050] Switching transistors Q1, Q2, Q3, and Q4 are IGBTs or SIC-MOSFETs. Switching transistors Q1, Q2, Q3, and Q4 control the conduction and cutoff of the circuit through electric field or current signals. The digital circuit acts as an electronic switch in the logic circuit to achieve signal routing. Signal amplification adjusts the source-drain current through the gate voltage to amplify weak signals. The switching transistor has characteristics such as fast response (i.e., nanosecond-level response), low conduction loss, high reliability, and no mechanical wear, making it the core component of modern electronic systems.

[0051] Figure 2The steepening diodes D1, D2, the buffer capacitor Cd, the current-limiting resistors Rd1, Rd2, the power supplies VDC1 and VDC2 form a bipolar pulse front steepening circuit. Its principle is to utilize the reverse recovery characteristic of the diode to achieve the steepening of the pulse output rising edge. When no high-voltage pulse is generated, that is, when the switching transistors Q1, Q2, Q3, and Q4 are all turned off, the power supply VDC1, the current-limiting resistor Rd1, and the steepening diode D1 form a forward conduction path, and there is a forward current flowing through the steepening diode D1. Correspondingly, the power supply VDC2, the current-limiting resistor Rd2, and the steepening diode D2 form a forward conduction path, and there is a forward current flowing through the steepening diode D2. To reduce current loss and the heating of the current-limiting resistors Rd1 and the power supply Rd2, a switch can also be added to control the output of VDC1 and VDC2, and just turn on the output of VDC1 and VDC2 in advance before the pulse output, and disconnect at other times.

[0052] When a positive pulse is generated, the switching transistors Q1 and Q3 are turned on. Due to the reverse recovery characteristic of the steepening diode D1, at the rising front edge of the pulse, the switching transistor Q1, the steepening diode D1, the buffer capacitor Cd, the steepening diode D2, and the switching transistor Q3 form a path, and the current flowing through the load RL decreases, that is, the voltage measured across the load RL decreases, which plays the role of steepening the front edge. As the reverse recovery of the steepening diode D1 ends and reaches the reverse cut-off state, the current flowing through D1 is 0, and the switching transistor Q1, the load RL, and the switching transistor Q3 form a conduction path.

[0053] Similarly, when a negative pulse is generated, the switching transistors Q2 and Q4 are turned on. Due to the reverse recovery characteristic of the steepening diode D2, at the rising edge of the pulse, the switching transistor Q4, the steepening diode D2, the buffer capacitor Cd, the steepening diode D1, and the switching transistor Q2 form a path, and the current flowing through the load RL also decreases. As the reverse recovery of the steepening diode D2 ends and reaches the reverse cut-off state, the current flowing through D2 is 0, and the switching transistor Q4, the load RL, and the switching transistor Q2 form a conduction path.

[0054] Since the solution given in this patent is based on the reverse recovery characteristic of the diode, the steepening effect depends on the reverse recovery current of the steepening diode. The required steepening effect can be achieved by adjusting the voltages of VDC1 and VDC2, the resistances of the current-limiting resistors Rd1 and Rd2, the number of parallel connections of the steepening diodes D1 and D2, etc.

[0055] Specifically, each path of the diodes uses 3 strings in parallel with 6 in each string, a total of 36 diodes. The buffer capacitor uses two 2000V / 1uF capacitors in series, and the current-limiting resistor uses two 50-ohm resistors in parallel, achieving the steepening waveform effect, as Figure 4 shown.

[0056] Both the steepening diode D1 and the steepening diode D2 are composed of multiple groups of diodes connected in parallel. The steepening diode D1 or the steepening diode D2 includes 6 groups of diode groups connected in parallel, and each diode group is composed of 3 series-connected 2 diodes.

[0057] Connecting diodes in parallel can effectively improve the reliability of the circuit. When one diode fails, the other parallel-connected diodes can continue to work, thus ensuring the overall stability of the circuit. Parallel diodes can share the current together, thereby increasing the current-carrying capacity of the entire circuit. This is particularly important in electronic devices that need to handle large currents, such as power supplies, motor drives, etc. By connecting multiple diodes in parallel, the damage caused by excessive current carried by a single diode can be effectively avoided, improving the safety and stability of the circuit. After multiple diodes are connected in parallel, their equivalent internal resistance will decrease accordingly. This helps to reduce the voltage drop in the circuit and improve the power supply efficiency. At the same time, it can also make the circuit more sensitive to changes in the external load and achieve a faster response.

[0058] Connecting diodes in series can significantly improve the voltage withstand capacity of the entire circuit. The series-connected diode combination can withstand a higher voltage, so it has important application value in high-voltage circuits. For example, in the power system, the insulation level of equipment can be improved by connecting diodes in series to ensure the safe operation of the power system. In a circuit that requires precise voltage control, more precise voltage regulation can be achieved by connecting diodes in series. Since the forward voltage drop of each diode is known, a predetermined voltage division effect can be achieved after series connection, thus meeting the requirements of specific applications. Series-connected diodes can also be used as protection components. When overvoltage or overcurrent occurs in the circuit, the diode will be damaged due to reverse breakdown or forward thermal breakdown, thereby cutting off the circuit and protecting other electronic components from damage. This application method is called diode sacrificial protection and is often used to protect expensive equipment or key circuits.

[0059] A steepened circuit can significantly improve the switching speed because the steepened pulse front can change the voltage state faster, thus reducing the switching time. A steepened circuit can reduce electromagnetic interference because the steepened pulse front and rear edge can reduce the generation of harmonics, thus reducing the interference to other electronic devices. In high-frequency applications, a steepened circuit can provide more stable signal transmission and lower signal distortion, thereby improving the overall performance of the system. In power supply design, a steepened circuit can improve the transient response of the power supply, reduce voltage fluctuations, and provide a more stable power output. A steepened circuit can reduce harmonic components, reduce electromagnetic interference, and improve the anti-interference ability of the system. In high-speed digital circuits, the steepened signal edges can reduce signal reflection and crosstalk, improving the signal integrity and transmission quality.

[0060] The main function of the high-voltage pulse front steepening circuit is to shorten the pulse rise time, make the pulse front steeper, that is, reach the peak faster, so as to improve the instantaneous power and accuracy of the pulse signal. Compress the originally gentle rising edge to the picosecond or sub-nanosecond level, generating a more ideal square-wave pulse. Filter out the low-frequency components of the pulse and retain the high-frequency components to make the waveform sharper. A steep pulse front can more accurately mark the moment when an event occurs, and is applicable to fields such as radar ranging, laser triggering, and particle detection that require high time accuracy. Shortening the rise time can achieve a higher instantaneous electric field strength at the same voltage; a fast switch can reduce the energy dissipation during the transition process and improve the system efficiency. When transmitting over a long distance or with poor load matching, a steep front can reduce the waveform broadening caused by dispersion or reflection.

[0061] Of course, it can also be further optimized by adjusting the number of diodes, the resistance value of the current-limiting resistor, and the capacitance value of the buffer capacitor. It is found in actual tests that the current-limiting resistor has a heating problem. In actual applications, it can be solved by increasing the switch to control the outputs of VDC1 and VDC2, and turning on the outputs of VDC1 and VDC2 in advance before the pulse output, and disconnecting them at other times.

[0062] This circuit is a high-voltage pulse generation circuit based on an H-bridge, rather than a Marx circuit. The H-bridge circuit has the advantages of relatively simple control, high repetition frequency, and low harmonic distortion compared to the Marx circuit solution.

[0063] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present invention, and any reference signs in the claims should not be regarded as limiting the claims involved.

[0064] In addition, it should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A high-voltage pulse front steepening circuit based on an H-bridge, characterized in that, It includes a switching transistor Q1, a switching transistor Q2, a switching transistor Q3, a switching transistor Q4, and a load RL. The collector of the switching transistor Q1 is connected to the power supply VH; the emitter of the switching transistor Q1 is connected to the collector of the switching transistor Q2; the collector of the switching transistor Q4 is connected to the power supply VH; the emitter of the switching transistor Q4 is connected to the collector of the switching transistor Q3; the emitters of the switching transistor Q2 and the switching transistor Q3 are both grounded; one end of the load RL is connected to the emitter of the switching transistor Q1, and the other end of the load RL is connected to the emitter of the switching transistor Q4.

2. The high-voltage pulse front steepening circuit based on an H-bridge according to claim 1, characterized in that, The base of the switching transistor Q1 and the base of the switching transistor Q3 are connected to an external control signal; the base of the switching transistor Q2 and the base of the switching transistor Q4 are connected to another external control signal.

3. The high-voltage pulse front steepening circuit based on an H-bridge according to claim 2, characterized in that, The emitter of the switching transistor Q1 is connected to the negative pole of the power supply VDC1; the positive pole of the power supply VDC1 is connected to one end of the current-limiting resistor Rd1, the other end of the current-limiting resistor Rd1 is connected to the positive pole of the steepening diode D1, and the negative pole of the steepening diode D1 is connected to the emitter of the switching transistor Q1.

4. The high-voltage pulse front steepening circuit based on an H-bridge according to claim 3, wherein The emitter of the switching transistor Q4 is connected to the negative pole of the power supply VDC2; the positive pole of the power supply VDC2 is connected to one end of the current-limiting resistor Rd2, the other end of the current-limiting resistor Rd2 is connected to the positive pole of the steepening diode D2, and the negative pole of the steepening diode D2 is connected to the emitter of the switching transistor Q4.

5. The high-voltage pulse front steepening circuit based on an H-bridge according to claim 4, wherein The positive pole of the steepening diode D1 is connected to one end of the buffer capacitor Cd, and the other end of the buffer capacitor Cd is connected to the positive pole of the steepening diode D2.

6. The high-voltage pulse front steepening circuit based on an H-bridge according to claim 5, characterized in that, The switching transistors Q1, Q2, Q3, and Q4 are IGBTs or SIC-MOSFETs.

7. The high-voltage pulse front steepening circuit based on an H-bridge according to claim 6, characterized in that, Both the steepening diode D1 and the steepening diode D2 are composed of multiple groups of diodes connected in parallel.

8. The high-voltage pulse front steepening circuit based on an H-bridge according to claim 7, wherein, The steepening diode D1 or the steepening diode D2 includes 6 groups of diode groups connected in parallel, and each diode group is composed of 3 two-diode series-connected structures.

9. The high-voltage pulse front steepening circuit based on an H-bridge according to claim 8, wherein The buffer capacitor Cd is composed of two 2000V / 1uF capacitors connected in series.

10. The high-voltage pulse front steepening circuit based on an H-bridge according to claim 9, characterized in that, The current-limiting resistor Rd1 or the current-limiting resistor Rd2 is composed of two 50-ohm resistors connected in parallel.

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