Low temperature plasma arc starting system and method

Abstract

The application discloses a low-temperature plasma arc starting system and an arc starting method, and belongs to the technical field of medical devices. A system main power module outputs a direct current voltage signal to a full-bridge output module, a controller controls a full-bridge driving waveform generating circuit to modulate an adjustable direct current voltage signal into a pulse signal with a predetermined pulse width, the full-bridge output module converts the pulse signal with the predetermined pulse width into a square wave pulse signal and outputs the square wave pulse signal to a resonant power amplifier module, and the resonant power amplifier module boosts the square wave pulse signal and outputs a predetermined resonant pulse signal to a load. Compared with a traditional sine wave output arc starting mode, the low-temperature plasma platform arc starting system and the arc starting method can greatly shorten the time from a wave peak to a wave trough in one period, significantly improve the energy concentration degree and the size of instantaneous energy, solve the problem of low arc starting probability under the condition of non-contact tissue when the electrode is in the sine wave output, and do not increase the cost of redundant hardware, so the method is easy to popularize and apply.

Description

TECHNICAL FIELD

[0001] The application relates to a low-temperature plasma arc starting system and an arc starting method, and belongs to the technical field of medical instruments. BACKGROUND

[0002] Low-temperature plasma ablation technology has been gradually developed and widely applied in the field of clinical medical treatment due to its great advantages. At present, the plasma energy platform is widely applied in urology. In the plasma energy platform, selecting appropriate discharge conditions to improve the discharge efficiency, especially the output current, voltage characteristics, electrode spacing and electrode relative area and other factors, has become a technical difficulty.

[0003] The traditional plasma energy platform needs to generate a sine wave at the output end of the electrode to ionize physiological saline, and then adjust the output according to different tissue impedance needs and clinical requirements. However, the ionization rate of the sine wave for physiological saline is low, and the rising and falling time of the wave crest and trough is long, which cannot start the arc at one time and is not conducive to the rapid generation of plasma, and cannot meet the actual needs of clinical cutting thin tissues or non-contact tissues in urology. In addition, the working temperature range of the traditional plasma energy platform is 40-70 DEG C, which has a certain risk for the application of the plasma energy platform in urology.

[0004] The application designs a low-temperature plasma rapid and accurate arc starting system and arc starting method. In the early stage of electrode arc starting, the output mode of the square wave is used in a short time, which solves the problem of long rising and falling time of the wave crest and trough in the early stage of electrode arc starting of the traditional sine wave, makes the dissipation power between the electrodes maximum, is more conducive to the generation of plasma, and the temperature of the plasma energy platform can be controlled within 45 DEG C, thereby reducing the risk of the system. SUMMARY

[0005] TECHNICAL PROBLEMS TO BE SOLVED BY THE INVENTION

[0006] The application proposes a low-temperature plasma arc starting system and arc starting method aiming at the problems of long arc starting time and slow plasma generation speed of the low-temperature plasma platform.

[0007] TECHNICAL SCHEME

[0008] To achieve the above-mentioned purpose, the first technical scheme of the application provides a low-temperature plasma arc starting system, which comprises

[0009] A main power module is used to output a direct-current voltage signal.

[0010] A controller is used to control the full-bridge driving waveform generating circuit to modulate the adjustable direct-current voltage signal into a pulse signal with a predetermined pulse width.

[0011] The full-bridge output module converts the pulse signal with the predetermined pulse width into a square wave pulse signal.

[0012] The resonant power amplifier module receives the square wave pulse signal and outputs a predetermined resonant pulse signal to a load.

[0013] Further, the resonant power amplifier module further comprises a transformer and a first DC blocking capacitor for blocking a DC component, the first DC blocking capacitor being arranged between the full-bridge output module and the transformer and being connected in series with a first winding of the transformer.

[0014] Further, the resonant power amplifier module further comprises a second matching capacitor and a third matching capacitor, one end of the second matching capacitor being connected in series with one end of a second winding of the transformer, and the other end of the second matching capacitor being a first resonant power amplifier output end; one end of the third matching capacitor being connected in series with the other end of the second winding of the transformer, and the other end of the third matching capacitor being a second resonant power amplifier output end.

[0015] Further, the resonant power amplifier module further comprises at least one load capacitor, one end of the load capacitor being connected to the first resonant power amplifier output end, and the other end of the load capacitor being connected to the second resonant power amplifier output end.

[0016] Further, the full-bridge drive waveform generation circuit comprises:

[0017] A first resistor, one end of which is connected to the controller, and the other end of which is connected to one end of a first NAND gate, the other end of the first NAND gate being connected to one end of a third NAND gate, and the other end of the third NAND gate being output to the full-bridge output module.

[0018] A second resistor, one end of which is connected to the controller, and the other end of which is connected to a second NAND gate, the other end of the second NAND gate being connected to one end of a fourth NAND gate, and the other end of the fourth NAND gate being output to the full-bridge output module.

[0019] The third NAND gate and the fourth NAND gate are connected.

[0020] A third resistor, one end of which is connected to the controller, and the other end of which is connected to the third NAND gate and the fourth NAND gate.

[0021] Further, a resonant output sampling module is further included, which collects signals of the resonant power amplifier module, and outputs the signals to the controller, and the controller adjusts the power output according to the signals.

[0022] Further, the resonant output sampling module is composed of a signal conversion module, a full-wave rectification module, and a signal amplification module connected in series.

[0023] The second technical solution provided by the application is an arc starting method of a low-temperature plasma arc starting system, comprising a main power module, a full-bridge output module, a resonant power amplifier module, a full-bridge driving waveform generation circuit, a resonant output sampling module, a controller and a load.

[0024] The main power module outputs a direct current voltage signal;

[0025] The direct current voltage signal is modulated into a pulse signal with a predetermined pulse width;

[0026] The pulse signal with the predetermined pulse width becomes a square wave pulse signal;

[0027] The square wave pulse signal is boosted to generate a high-voltage pulse square wave signal acting on the load;

[0028] The resonant output sampling module collects current and voltage signals and calculates an impedance value;

[0029] If the impedance value is greater than a set threshold value, the arc starting is successful;

[0030] Otherwise, the load continues to receive the high-voltage pulse square wave signal.

[0031] Further, the resonant output sampling module collects signals of the resonant power amplifier module, and the controller receives the collected signals, adjusts the output power of the power module, and the signals include at least one of current, voltage or power.

[0032] Advantages

[0033] Compared with the traditional sine wave output arc starting mode, the low-temperature plasma arc starting system and the arc starting method can greatly shorten the time from the wave peak to the wave trough in one period, significantly improve the energy concentration and the size of the instantaneous energy.

[0034] In actual clinical application, especially in the surgery of prostatic hyperplasia in urology, the one-time arc starting probability of the arc starting method on thin tissues or non-contact tissues is close to 100%, solving the problem of low arc starting probability in the case of non-contact tissues when the electrode outputs a sine wave.

[0035] Compared with the traditional sine wave arc starting time, the arc starting system has a short square wave arc starting time, small energy demand and no additional hardware cost, and is easy to popularize and apply. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 The figure is a composition block diagram of the low-temperature plasma energy platform arc starting system.

[0037] Figure 2 The figure is a circuit diagram of the system full-bridge output module and the resonant power amplifier module.

[0038] Figure 3 The circuit diagram for the system resonant output sampling module;

[0039] Figure 4 The circuit diagram for the full-bridge drive waveform generation circuit of the system is shown below.

[0040] Figure 5 The voltage waveform during the arc initiation phase of the ultrapulse generated by the low-temperature plasma system in the urology department;

[0041] Figure 6 This is a comparison diagram of a superpulse sine wave and a superpulse square wave. Detailed Implementation

[0042] To further understand the content of this invention, it will be described in detail with reference to the accompanying drawings and specific embodiments.

[0043] Example 1

[0044] like Figure 1 As shown, this invention provides a low-temperature plasma platform arc initiation system, including a main power supply module for outputting a DC voltage signal to a full-bridge output module; a controller controls a full-bridge drive waveform generation circuit to modulate the adjustable DC voltage signal into a pulse signal with a predetermined pulse width; the full-bridge output module converts the pulse signal with the predetermined pulse width into a square wave pulse signal and outputs it to a resonant power amplifier module; the resonant power amplifier module boosts the square wave pulse signal and outputs a predetermined resonant pulse signal to the load. Optionally, the voltage received by the main power supply module in this invention mainly comes from the AC voltage input from the mains power supply and is then converted into a DC voltage signal for output.

[0045] In this embodiment, the voltage pulse signal is 170VDC (volt direct voltage) / 13A (ampere), which can provide the energy to excite the plasma in 20ms.

[0046] Optionally, this embodiment also includes a resonant output sampling module, with the output terminal of the resonant power amplifier module connected to the input terminal of the resonant output sampling module. The resonant output sampling module samples at least one of the output voltage signal, current signal, or power signal of the resonant power amplifier module and outputs it to the controller.

[0047] The controller performs calculations and connects the results to the input of the power module via output terminal 1 to adjust the power output; it also connects to the input of the full-bridge drive waveform generator circuit via output terminal 2 to control the full-bridge drive waveform generator circuit, which modulates the DC voltage signal into a pulse signal with a predetermined pulse width.

[0048] The output of the full-bridge drive waveform generator circuit is connected to the input of the full-bridge output module.

[0049] like Figure 2The circuit diagram of full-bridge output module and resonant power amplifier module is shown. The full-bridge output module receives PWM1 and PWM2 output by full-bridge driving waveform generating circuit (such as Figure 4 The full-bridge output module is used to convert power supply voltage into alternating square wave of certain frequency, and the circuit thereof is composed of four triodes Q1-Q4. Triode Q1 is connected in series with triode Q2, and the source of triode Q1 is connected with the drain of triode Q2. Triode Q3 is connected in series with triode Q4, and the source of triode Q3 is connected with the drain of triode Q4. Triode Q1 / Q2 is connected in parallel with triode Q3 / Q4. The source of triode Q1 and the source of triode Q3 are two output ports of the full-bridge output module, and the output is used as the input of the resonant power amplifier. The source of triode Q3 is connected in series with the first DC blocking capacitor C6 in the resonant power amplifier module. One end of the first DC blocking capacitor C6 is connected with the first winding of transformer T1, and the other end of the first winding of transformer T1 is connected with the drain of triode Q2. The first DC blocking capacitor C6 is used to filter DC component.

[0050] As shown in Figure 2 In the resonant power amplifier module, one end of the second winding of transformer T1 is connected in series with one end of the second matching capacitor C3, and the other end is connected in series with one end of the third matching capacitor C2. The other end of the second matching capacitor C3 is the first resonant power amplifier output terminal A, and the other end of the third matching capacitor C2 is the second resonant power amplifier output terminal B. In this embodiment, C6, T1, C2 and C3 constitute a step-up resonant network, which is used to step up the alternating square wave output by the full-bridge output. The third matching capacitor C2 and the second matching capacitor C3 are used to adjust the output impedance characteristics. The resonant power amplifier module further comprises at least one load capacitor. In this embodiment, three load capacitors C1, C4 and C5 constitute a false load of the resonant power amplifier module output. One end of the load capacitor C1 is connected with the first resonant power amplifier output terminal A, and one end of the load capacitor C5 is connected with the second resonant power amplifier output terminal B. The load capacitors C1, C4 and C5 are connected in series. The resonant power amplifier output terminals A and B output square wave of certain frequency and Vp-p of 600V. The series connection of the load capacitors C1, C4 and C5 constitutes a false load for impedance matching of the resonant network output terminal.

[0051] As shown in Figure 3 The circuit diagram of the system resonant output sampling module is shown. The system resonant output sampling module is composed of a signal conversion module, a full-wave rectification module and a signal amplification module connected in series.

[0052] The signal conversion module is composed of a mutual inductor T1 and a resistor R6 connected in parallel. In this embodiment, T1 is a mutual inductor with a transformation ratio of 50:1, which is used to step down the current and voltage signals output by the resonant network. The resistor R6 is used to convert the current signal into a voltage signal.

[0053] Full-wave rectification module is mainly composed of operational amplifier U1B, D1, D2, R7, wherein D1, D2 is parallel relationship, in high frequency zero sine wave in alternate conduction with operational amplifier U1 constitutes negative feedback, resistance R7 and D1 series relationship, form the negative feedback loop of the negative part of the sine wave; resistance R4, R7, R1, R2 and operational amplifier U1A constitute signal amplification part, wherein resistance R1 and R2 parallel relationship, as signal amplification effect matching resistance.

[0054] Signal filtering part converts the DC signal amplified by the full-wave rectification part for the single-chip microcomputer sampling; wherein resistance R8, R9 is parallel for signal amplification coefficient matching effect; the third matching capacitor C2 and resistance R9 are connected in parallel for signal filtering.

[0055] As Figure 4 The full-bridge driving waveform generation circuit is shown in the circuit diagram, and the full-bridge driving waveform generation circuit is composed of four NAND gates U1-U4, first resistors R6, R12 and R13, wherein: one end of the first resistor R6 is connected to the output of the controller, the other end is connected to the input end of the first NAND gate U1, and the two are connected in series and then output to the third NAND gate U3, and the signal PWM1 is obtained after the third NAND gate U3 is processed; one end of the resistor R12 is connected to the output of the controller, and the other end is connected to the third NAND gate U3 and the fourth NAND gate U4; one end of the second resistor R13 is connected to the output of the controller, and the other end is connected to the input end of the second NAND gate U2, and the two are connected in series and then output to the fourth NAND gate U4, and the signal PWM2 is obtained after the fourth NAND gate U4 is processed; PWM1 and PWM2 are output to the full-bridge output module for driving the four triodes in the full-bridge output module in the system resonant network.

[0056] The four NAND gates U1, U2, U3 and U4 constitute a logic gate circuit; the first resistor R6 and the second resistor R13 are used for receiving the complementary square wave sent by the controller, and the third resistor R12 is used for receiving the PWM with variable duty cycle sent by the controller; after the logic gate, the complementary square wave with controllable duty cycle, namely PWM1 and PWM2, is output.

[0057] Embodiment two

[0058] The application also provides an arc starting method of a low-temperature plasma arc starting system, which comprises a main power module, a full-bridge output module, a resonant power amplifier module, a full-bridge driving waveform generation circuit, a resonant output sampling module, a controller and a load.

[0059] Step 1, the main power module receives the alternating current signal output by the mains, and outputs a direct current voltage signal to the full-bridge output module;

[0060] Step 2, the controller controls the full-bridge driving waveform generation circuit to modulate the direct current voltage signal into a pulse signal with a predetermined pulse width;

[0061] Step 3, the full-bridge output module converts the pulse signal with a predetermined pulse width into a square wave pulse signal, at which time the first voltage boost is performed.

[0062] Step 4, the resonant power amplifier module generates a high-voltage pulse square wave signal acting on the load after the square wave pulse signal is boosted again;

[0063] Step 5, the resonant output sampling module collects the current and voltage signals fed back by the resonant power amplifier module and calculates the impedance value;

[0064] Step 6, if the impedance value is greater than the set threshold value, the arc striking is successful, at which time the arc striking pulse of the system will become a stable arc pulse;

[0065] Step 7, if the impedance value is less than the set threshold value, it indicates that the arc striking is unsuccessful, and the load continues to receive the high-voltage pulse square wave signal until the arc striking is successful.

[0066] Optionally, the above technical solution two further comprises a resonant output sampling module for collecting the signals of the resonant power amplifier module, and the controller receives the collected signals, adjusts the output power of the power module, and the signals include at least one of current, voltage or power.

[0067] The urinary tract plasma system using the above technical solution one and technical solution two, when the system pedal instruction is in the cutting state, the controller starts to configure the power module to output 170V for the initial stage voltage of the super pulse arc striking, delays for 10ms, collects the voltage and current data of the resonant output for calculating the impedance value, and judges whether the physiological saline impedance reaches the set threshold value, if the value of the plasma state impedance is reached, the super pulse arc striking is successful, and the stable arc working maintaining state is performed. If the impedance value does not reach the value of the plasma state impedance, the controller continues to control the driving waveform generation circuit to modulate the pulse signal output by the power module into a pulse signal with a predetermined pulse width.

[0068] Figure 5 The voltage waveform of the super pulse arc striking process of the low-temperature plasma arc striking system is generated. In the figure, stage 1 is the super pulse arc striking start stage, stage 2 is the super pulse arc striking end stage, and stage 3 is the pulse maintaining stage. As can be seen from the figure, the time from the super pulse arc striking start to the end is about 20ms, the energy required by the super pulse is about 5 times of the maintaining, the energy required by the super pulse arc striking stage is about 600V, 13A; once the arc striking is successful, the energy required by the super pulse maintaining stage is only about 600V, 2A; the energy required by the super pulse arc striking and the voltage of the maintaining stage are both about 600V p-p peak voltage, but the current intensity of the super pulse arc striking stage is about 6-7 times of the maintaining stage.

[0069] The comparison chart of the super pulse sine wave and the super pulse square wave generated by the system is as follows Figure 6As shown in the figure, the left part of the figure shows a sine wave with a Vp-p (peak-peak value) of 600V and a frequency of 300K; the right part of the figure shows a square wave generated by the system of the application with a Vp-p (peak-peak value) of 600V and a frequency of 300K. As can be seen from the figure, the time from the Vp-p valley to the peak of the 300K sine wave is 1.5us; the time from the Vp-p valley to the peak of the 300K square wave is less than 5ns; the square wave is obviously superior to the sine wave in terms of energy concentration and size.

[0070] The system and method for rapid and accurate arc striking of the low-temperature plasma system for urology designed by the application adopts a square wave output mode in a short time at the initial stage of electrode arc striking, solves the problem of long rising and falling time from the wave peak to the wave valley of the traditional sine wave at the initial stage of electrode arc striking, maximizes the dissipated power between the electrodes, is more conducive to the generation of plasma, and can control the temperature of the plasma energy platform within 45℃. The low-temperature plasma system for urology designed by the application activates the urology electrode according to a certain frequency, and the water temperature data and time data records in a saline environment are as shown in Table 1:

[0071] Table 1 Water temperature data and time data records in a saline environment

[0072]

[0073] As can be seen from the test data in Table 1, under the condition of applying super pulse on the electrode, the electrode 1, the electrode 2 and the electrode 3 improve the arc striking ability, and the water temperature does not exceed 45℃ within 105min.

[0074] The low-temperature plasma system for urology designed by the application tests the arc temperature between the electrodes, adds control group 1 and control group 2, and the power and temperature are as shown in Table 2:

[0075]

[0076] Control group 1 is set to 50W, control group 2 is set to 100W, and cannot be arc struck at one time, resulting in a very high arc temperature between the electrodes. The low-temperature plasma system for urology designed by the application can realize one-time arc striking from 140W to 350W, and the arc temperature between the electrodes is very low.

[0077] The above description of the application and its embodiments is illustrative and not limiting, and the embodiments shown in the drawings are only one of the embodiments of the application, and the actual structure is not limited thereto. Therefore, if a person skilled in the art is inspired thereby, without departing from the purpose of the application, similar structural modes and embodiments can be designed without creativity, which shall belong to the protection scope of the application.

Claims

1. A low-temperature plasma arc initiation system, characterized in that, include The main power supply module is used to output DC voltage signals; The controller controls the full-bridge drive waveform generation circuit to modulate the DC voltage signal into a pulse signal with a predetermined pulse width; The full-bridge output module converts the pulse signal with a predetermined pulse width into a square wave pulse signal; The resonant power amplifier module is used to receive the square wave pulse signal and output a predetermined resonant pulse signal to the load. The resonant power amplifier module also includes a transformer and a first DC blocking capacitor for isolating the DC component. The first DC blocking capacitor is located between the full-bridge output module and the transformer and is connected in series with the first winding of the transformer.

2. The low-temperature plasma arc initiation system according to claim 1, characterized in that, The resonant power amplifier module further includes a second matching capacitor and a third matching capacitor. One end of the second matching capacitor is connected in series with one end of the second winding of the transformer, and the other end of the second matching capacitor is the output terminal of the first resonant power amplifier. One end of the third matching capacitor is connected in series with the other end of the second winding of the transformer, and the other end of the third matching capacitor is the output terminal of the second resonant power amplifier.

3. The low-temperature plasma arc initiation system according to claim 2, characterized in that, The resonant power amplifier module also includes at least one load capacitor, one end of which is connected to the output terminal of the first resonant power amplifier and the other end of which is connected to the output terminal of the second resonant power amplifier.

4. The low-temperature plasma arc initiation system according to claim 3, characterized in that, The full-bridge drive waveform generation circuit includes: The first resistor has one end connected to the controller and the other end connected to one end of the first NAND gate. The other end of the first NAND gate is connected to one end of the third NAND gate. The other end of the third NAND gate is output to the full-bridge output module. The second resistor has one end connected to the controller and the other end connected to the second NAND gate. The other end of the second NAND gate is connected to one end of the fourth NAND gate, and the other end of the fourth NAND gate is output to the full-bridge output module. The third NAND gate and the fourth NAND gate are connected; The third resistor has one end connected to the controller and the other end connected to the third NAND gate and the fourth NAND gate.

5. The low-temperature plasma arc initiation system according to any one of claims 2-4, characterized in that, The system also includes a resonant output sampling module, which collects the signal from the resonant power amplifier module. The resonant output sampling module outputs a signal to the controller, and the controller adjusts the output of the main power module according to the signal.

6. The low-temperature plasma arc initiation system according to claim 5, characterized in that, The resonant output sampling module is composed of a signal conversion module, a full-wave rectification module, and a signal amplification module connected in series.

7. A method for initiating an arc in a low-temperature plasma arc initiation system, characterized in that, The system includes a main power supply module, a full-bridge output module, a resonant power amplifier module, a full-bridge drive waveform generation circuit, a resonant output sampling module, a controller, and a load; The steps for initiating an arc are as follows: Step S1: Configure the main power module to output a DC voltage signal; Step S2, the DC voltage signal is modulated into a pulse signal with a predetermined pulse width; Step S3: The pulse signal with a predetermined pulse width is converted into a square wave pulse signal; Step S4: After the square wave pulse signal is boosted, a high-voltage pulse square wave signal is generated and applied to the load. Step S5: The resonant output sampling module acquires current and voltage signals and calculates the impedance value; Step S6: If the impedance value is greater than the set threshold, the arc initiation is successful; In step S7, if the impedance value is less than the set threshold, it indicates that the arc initiation was unsuccessful, and the load continues to receive the high-voltage pulse square wave signal.

8. The arc initiation method of the low-temperature plasma arc initiation system according to claim 7, characterized in that, The system also includes a resonant output sampling module to collect signals from the resonant power amplifier module. The controller receives the collected signals and adjusts the output power of the power supply module. The signals include at least one of current, voltage, or power.

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