Novel plasma operation device and control method

Abstract

The invention provides a novel plasma operation device and a control method, and solves the problems of low arcing rate and the like of an operation device plasma system, the novel plasma operation device comprises a power supply board and a main control board, a common-mode filtering and rectifying module is arranged in the power supply board, the common-mode filtering and rectifying module is connected with a power amplifier circuit through a full-bridge DC / DC module, and the power amplifier circuit is connected with the main control board. The power amplifier circuit is connected with the output connection electrode through the output resonance circuit; an MCU module is arranged in the main control board, the MCU module is connected with the full-bridge DC / DC module through a PWM controller, the MCU module is connected with the power amplifier circuit through an MOS driving module, the output resonance circuit is connected with the MCU module through a current sampling module and a voltage sampling module, an effective value conversion module is arranged between the output resonance circuit and the MCU module, and the output connection electrode is connected with the MCU module through an electrode identification module. The method has the advantages of being high in arcing rate, good in safety and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of plasma surgical equipment, and in particular relates to a novel plasma surgical device and a control method. Background Art

[0002] At present, plasma surgical equipment in the industry can realize plasma electrocuting and electrocoagulation operations on human soft tissues in a saline environment. The key lies in how to cut the tissue quickly and smoothly while causing less thermal damage to the tissue when using the plasma arc to perform electrocute. In actual applications, plasma surgery generally goes through the following process. After the plasma electrocute is started, the plasma surgical electrode first loads an initial power P0 to make the front end of the plasma surgical electrode output a plasma state, commonly known as arcing. After arcing, the load impedance increases, and the plasma surgical electrode continuously outputs the electrocute power P1 to cut the tissue. After the cutting is completed, the energy output is turned off. During the arc starting stage, an instantaneous power P0 that is much larger than the P1 output power is required to allow the front end of the plasma surgical electrode to quickly start an arc, generally between a few milliseconds and tens of milliseconds. A P0 power that is too small is not easy to start an arc or the arc starting time is too long, affecting the clinical effect. Similarly, during tissue cutting, the load impedance will change in real time, ranging from hundreds of ohms to thousands of ohms. If the entire load maintains a constant power before the impedance changes, especially during high impedance, an excessively high peak voltage will be output, causing excessive thermal damage to the tissue, and even carbonization, which cannot reflect the advantages of low-temperature electrosurgical cutting in plasma surgery. At the same time, excessive energy output will also increase safety risks.

[0003] In order to solve the deficiencies of the existing technology, people have conducted long-term exploration and proposed various solutions. For example, a Chinese patent document discloses a constant power circuit for a low-temperature plasma surgery system [201721465089.4], which samples the output current through a current transformer, converts the current signal into a voltage signal using a sampling resistor, and the two signals pass through a precision half-wave rectifier circuit and a filter circuit to obtain a DC current signal and a DC voltage signal. The two DC signals are respectively input to the single-chip microcomputer for AD conversion, and the single-chip microcomputer adjusts the voltage reference value, thereby changing the output voltage and current, so that no matter how the load changes, the output power is guaranteed to be constant.

[0004] The above solution solves the problem of output gear control to a certain extent, but the solution still has many shortcomings, such as low arc starting rate and other problems. Summary of the invention

[0005] The purpose of the present invention is to provide a new type of plasma surgical device with reasonable design and high arc starting rate in view of the above problems.

[0006] The object of the present invention is to provide a novel control method for a plasma surgical device with good operational safety in view of the above problems.

[0007] To achieve the above-mentioned purpose, the present invention adopts the following technical solutions: a new type of plasma surgical device, including a power board and a main control board, the power board has a built-in common-mode filtering and rectifying module, the common-mode filtering and rectifying module is connected to the power amplifier circuit through a full-bridge DC / DC module, and the power amplifier circuit is connected to the output connection electrode through an output resonant circuit; the main control board has a built-in MCU module, the MCU module is connected to the full-bridge DC / DC module through a PWM controller, the MCU module is connected to the power amplifier circuit through a MOS driving module, the output resonant circuit is connected to the MCU module through a current sampling module and a voltage sampling module, and an effective value conversion module is arranged between them, and the output connection electrode is connected to the MCU module through an electrode identification module.

[0008] In the above-mentioned novel plasma surgical device, the MCU module is connected to the speaker through the audio driver module.

[0009] In the above-mentioned novel plasma surgical device, the MCU module is connected to the touch screen and is connected to the foot switch via the foot detection module.

[0010] In the above-mentioned novel plasma surgical device, the main control board has a built-in isolated DC-DC module.

[0011] A novel control method for a plasma surgical device comprises the following steps:

[0012] S1: The AC220V power supply from the grid outputs +12V power to the low-voltage module through the switching power supply, and the other outputs +310V DC voltage through the common-mode filter and rectifier module on the power board;

[0013] S2: When the foot switch is pressed, the MCU module of the main control board controls the +310V voltage to output a digitally adjustable DC voltage VCT through the full-bridge DC / DC module isolation;

[0014] S3: The adjusted VCT voltage supplies power to the power amplifier circuit, and after being processed by the power amplifier circuit, it outputs a high-frequency and high-voltage square wave voltage to the output resonant circuit;

[0015] S4: After resonance, a high-voltage sinusoidal voltage of the corresponding frequency is output, and then the output connection electrode acts on human tissue to achieve electrocuting or electrocoagulation operation.

[0016] In the above-mentioned novel control method of plasma surgical device, the voltage of the DC voltage VCT in step S2 is set by the DA output module from the MCU module through the PWM controller.

[0017] In the above-mentioned novel control method of plasma surgical device, the voltage and current signals output by the output resonant circuit in step S4 are sampled and converted into effective values, and then transmitted to the AD sampling module inside the MCU module to realize digital sampling. The impedance and power parameters of the current load tissue are calculated through the MCU module, and compared with the preset gear parameters. The VCT voltage is adjusted through the DA output module, so that the output power reaches the expected target value.

[0018] In the above-mentioned novel control method of plasma surgical device, the VCT voltage output by the power amplifier circuit in step S4 is positively correlated with the power loaded on the load tissue, as follows:

[0019] V vct1 / V vct0 =V p1 / V p0 =I p1 / I p0 =SQRT(P p1 / P p0 );

[0020] V vct0 : The DC voltage output by VCT at time t0;

[0021] V vct1 : The DC voltage output by VCT at time t1;

[0022] V p0 : The effective value voltage applied to the patient at time t0;

[0023] V p1 : The effective value voltage applied to the patient at time t1;

[0024] I p0 : The effective current loaded to the patient at time t0;

[0025] I p1 : The effective current loaded to the patient at time t1;

[0026] P p0 : The power loaded to the patient at time t0;

[0027] P p1 : The power loaded to the patient at time t1;

[0028] SQRT(): Square root function.

[0029] In the above-mentioned novel control method of plasma surgical device, the output adjustment in step S4 is implemented in a segmented manner, and the electric cutting stage is controlled by a constant power and a constant voltage in parallel competition. The specific conversion is as follows:

[0030] V vct1_p =V vct0 *SQRT(P p1 / P p0 );

[0031] V vct1_v =V vct0 *V p1 / V p0；

[0032] V vct1_p : The VCT voltage that should be output at time t1 calculated using the constant power mode;

[0033] V vct1_v : The VCT voltage that should be output at time t1 calculated using the constant voltage mode.

[0034] In the above-mentioned novel control method of plasma surgical device, step S4 compares V vct1_p With V vct1_v The absolute value between them is the smaller one, and the smaller one wins the competition and obtains the control right, and controls the DA voltage of the DA output module corresponding to the VCT voltage. The VCT voltage is proportional to the DA voltage, as shown below:

[0035] V vct1 = k*V DA ;

[0036] V DA : DC voltage output by DA module;

[0037] k: gain coefficient.

[0038] Compared with the existing technology, the advantages of the present invention are: it adopts segmented power output control, which makes ionization arc starting faster, cutting smoother, thermal damage smaller, and clinical effect better; it has faster closed-loop control response, higher-precision output power control, small deviation between devices, and no need to manually adjust the expected power setting frequently during use, making operation more convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a schematic diagram of the device structure of the present invention;

[0040] In the figure, power board 1, main control board 2, audio drive module 21, speaker 22, touch screen 23, foot detection module 24, foot switch 25, isolation DC-DC module 26, common mode filtering and rectification module 3, full-bridge DC / DC module 4, power amplifier circuit 5, output resonant circuit 6, output connection electrode 7, MCU module 8, PWM controller 81, MOS drive module 82, current sampling module 83, voltage sampling module 84, electrode identification module 85, effective value conversion module 86. DETAILED DESCRIPTION

[0041] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0042] like Figure 1 As shown, a novel plasma surgical device includes a power board 1 and a main control board 2. The power board 1 has a built-in common-mode filtering and rectifying module 3. The common-mode filtering and rectifying module 3 is connected to the power amplifier circuit 5 through a full-bridge DC / DC module 4. The power amplifier circuit 5 is connected to the output connection electrode 7 through an output resonant circuit 6. The main control board 2 has a built-in MCU module 8. The MCU module 8 is connected to the full-bridge DC / DC module 4 through a PWM controller 81. The MCU module 8 is connected to the power amplifier circuit 5 through a MOS driving module 82. The output resonant circuit 6 is connected to the MCU module 8 through a current sampling module 83 and a voltage sampling module 84, and an effective value conversion module 86 is arranged between them. The output connection electrode 7 is connected to the MCU module 8 through an electrode identification module 85.

[0043] Specifically, the MCU module 8 is connected to the speaker 22 via the audio driver module 21. During electrocuting or electrocoagulation, sounds of different frequencies are output to remind the user. When the device fails, a sound alarm can also be used to remind the user.

[0044] In depth, the MCU module 8 is connected to a touch screen 23 and is connected to a foot switch 25 through a foot detection module 24. The touch screen 23 performs human-computer interaction with the user, and can realize data interaction with the main control board through a serial port or other communication methods. In addition, an electrode interface is also provided, through which the radio frequency energy generated by the device is output to the output connection electrode 7, and then acts on the patient's tissue through the output connection electrode 7 to realize the electrocute and electrocoagulate operation. The device is also provided with an interface for a foot switch 25, through which the foot switch 25 is connected, and the doctor can control the start and stop of the electrocute or electrocoagulation energy output of the device through the foot switch 25.

[0045] Furthermore, the main control board 2 has a built-in isolated DC-DC module 26. The power board 1 is provided with a power input interface, which is connected to the grid power to supply power to the device.

[0046] In this embodiment, the hardware circuits of the power board 1 and the main control board 2 are specially developed. The power board 1 adopts a full-bridge topology to realize the isolated output of the VCT DC voltage of the switching power supply part and the voltage output of the high-frequency AC sine wave of the power amplifier part. The key power transformer of the power amplifier transformer is wound with EE55 magnetic core, and the output inductor is wound with iron silicon aluminum magnetic ring. The circuit adopts high-power MOS tubes such as FDA24N50 to realize high-voltage and high-current switching. A dedicated PWM controller 81 such as UC3879DW is used to perform pulse width modulation of the VCT output voltage. The power amplifier circuit 5 outputs The output voltage adopts an isolation transformer with an optional UF16 core winding for voltage sampling, and the output current adopts a current transformer such as PE-51688NL to convert the current signal into voltage for sampling. The MCU module 8 adopts a general 32-bit ARM chip such as STM32F407, with AD sampling module and DA output module, the touch screen 23 adopts a general 7-inch capacitive touch serial port screen, the speaker 22 adopts an 8-ohm 2W general speaker, and the foot switch 25 input is isolated by an optical coupler such as TLP291 and then input to the MCU module 8 to realize foot level sampling. With the above circuit, the technology is relatively easy to implement, the components are easy to obtain, the cost is low, and the performance is stable and reliable.

[0047] A novel control method for a plasma surgical device comprises the following steps:

[0048] S1: The AC220V power supply from the grid outputs +12V power to the low-voltage module through the switching power supply, and outputs +310V DC voltage through the common-mode filter and rectifier module 3 on the power board 1; the low-voltage module includes the main control board 2, the touch screen 23, and the fan and other components;

[0049] S2: When the foot switch 25 is stepped on, the MCU module 8 of the main control board 2 controls the +310V voltage to be isolated and output as a digitally adjustable DC voltage VCT through the full-bridge DC / DC module 4;

[0050] S3: The adjusted VCT voltage supplies power to the power amplifier circuit 5, and after being processed by the power amplifier circuit 5, a high-frequency and high-voltage square wave voltage is output to the output resonant circuit 6;

[0051] S4: After resonance, a high-voltage sinusoidal voltage of a corresponding frequency is output, and then the voltage acts on human tissue through the output connection electrode 7 to achieve electrocuting or electrocoagulation operation.

[0052] In addition, the voltage level of the DC voltage VCT in step S2 is set by the DA output module from the MCU module 8 via the PWM controller 81 .

[0053] At the same time, in step S4, the voltage and current signals output by the output resonant circuit 6 are sampled and converted into effective values, and then transmitted to the AD sampling module inside the MCU module 8 to realize digital sampling. The impedance and power parameters of the current load organization are calculated through the MCU module 8, and compared with the preset gear parameters. The VCT voltage is adjusted through the DA output module, so that the output power reaches the expected target value.

[0054] It can be seen that the VCT voltage output by the power amplifier circuit 5 in step S4 is positively correlated with the power loaded on the load structure, as follows:

[0055] V vct1 / V vct0 =V p1 / V p0 =I p1 / I p0 =SQRT(P p1 / P p0 );

[0056] V vct0 : The DC voltage output by VCT at time t0;

[0057] V vct1 : The DC voltage output by VCT at time t1;

[0058] V p0 : The effective value voltage applied to the patient at time t0;

[0059] V p1 : The effective value voltage applied to the patient at time t1;

[0060] I p0 : The effective current loaded to the patient at time t0;

[0061] I p1 : The effective current loaded to the patient at time t1;

[0062] P p0 : The power loaded to the patient at time t0;

[0063] P p1 : The power loaded to the patient at time t1;

[0064] SQRT(): Square root function.

[0065] Obviously, the output adjustment in step S4 is implemented in a segmented manner. In the early stage of electrotomy, before arcing, the load impedance is low due to the influence of physiological saline, generally around 20-30 ohms. At this time, the output power P0 with a larger output is controlled. The instantaneous power of P0 can generally be selected between 700W and 1400W, and its duration period is between 20-100ms. After arcing is completed, the output impedance becomes larger, generally between hundreds of ohms and thousands of ohms. The electrotomy stage is controlled by a constant power and constant voltage parallel competition method. The specific conversion is as follows:

[0066] V vct1_p =V vct0 *SQRT(P p1 / P p0 );

[0067] V vct1_v =V vct0 *V p1 / V p0；

[0068] V vct1_p : The VCT voltage that should be output at time t1 calculated using the constant power mode;

[0069] V vct1_v : The VCT voltage that should be output at time t1 calculated using the constant voltage mode.

[0070] Preferably, step S4 compares V vct1_p With V vct1_v The absolute value between them is the smaller one, and the smaller one wins the competition and obtains the control right, and controls the DA voltage of the DA output module corresponding to the VCT voltage. The VCT voltage is proportional to the DA voltage, as shown below:

[0071] V vct1 = k*V DA ;

[0072] V DA : DC voltage output by DA module;

[0073] k: gain coefficient.

[0074] The DA module can be a digital-to-analog converter built into the MCU or an external dedicated digital-to-analog conversion chip or module. The output voltage value is controlled through communication between the MCU and the DA module, thereby controlling the size of the VCT DC voltage so that the energy loaded into the patient's tissue meets the expected setting.

[0075] Through the above-mentioned periodic closed-loop control, the energy loaded into the patient's tissue is output according to the value preset by the software, which improves the cutting smoothness while minimizing thermal damage and improving clinical effects. The periodic control interval time can generally be selected to be 1-10 milliseconds, and in this example, 2 milliseconds is preferred.

[0076] Compared with the existing technology, the output power is also controlled by MCU to achieve electrocautery and coagulation operations, but the mainstream technology on the market "controls the maximum power through the peak control circuit", which only controls the maximum output power at the initial stage of arc starting to protect the patient from greater harm, or "constant power circuit performs constant power control", which over-emphasizes constant power and does not consider that when the impedance is too high during electrocautery, the output voltage may be too high due to constant power control, causing greater thermal damage and increasing the safety risk of the patient.

[0077] This embodiment takes into account the actual operation of each stage of plasma electrosurgical cutting. In the early stage of arc starting, a large instantaneous power P0 is output. The instantaneous power is set by software. Under the condition of ensuring the safety of the patient, the Na ions in the physiological saline solution are ionized faster to complete the ionization arc starting action, and then enters a mode in which constant power and constant voltage compete for output. The constant power mode is mainly used for smooth cutting of tissues, and the constant voltage mode is mainly used to control the increased risk of thermal damage caused by excessive voltage when cutting and separating tissues. Through the implementation of this technology, the present device can achieve smoother plasma electrosurgical cutting, smooth cutting edges, less thermal damage, and better clinical effects.

[0078] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

[0079] Although this article uses more terms such as power board 1, main control board 2, audio drive module 21, speaker 22, touch screen 23, foot detection module 24, foot switch 25, isolated DC-DC module 26, common mode filtering and rectification module 3, full bridge DC / DC module 4, power amplifier circuit 5, output resonant circuit 6, output connection electrode 7, MCU module 8, PWM controller 81, MOS drive module 82, current sampling module 83, voltage sampling module 84, electrode identification module 85, effective value conversion module 86, etc., it does not exclude the possibility of using other terms. The use of these terms is only to more conveniently describe and explain the essence of the present invention; interpreting them as any additional restrictions is contrary to the spirit of the present invention.

Claims

1. A novel plasma surgical device, comprising a power board (1) and a main control board (2), characterized in that: The power board (1) has a built-in common-mode filtering and rectifying module (3), the common-mode filtering and rectifying module (3) is connected to a power amplifier circuit (5) via a full-bridge DC / DC module (4), and the power amplifier circuit (5) is connected to an output connection electrode (7) via an output resonant circuit (6); the main control board (2) has a built-in MCU module (8), the MCU module (8) is connected to the full-bridge DC / DC module (4) via a PWM controller (81), the MCU module (8) is connected to the power amplifier circuit (5) via a MOS driving module (82), the output resonant circuit (6) is connected to the MCU module (8) via a current sampling module (83) and a voltage sampling module (84), and an effective value conversion module (86) is provided therebetween, and the output connection electrode (7) is connected to the MCU module (8) via an electrode identification module (85).

2. A novel plasma surgical device according to claim 1, characterized in that: The MCU module (8) is connected to the speaker (22) via the audio driver module (21).

3. A novel plasma surgical device according to claim 1, characterized in that: The MCU module (8) is connected to a touch screen (23) and is connected to a foot switch (25) via a foot detection module (24).

4. A novel plasma surgical device according to claim 1, characterized in that: The main control board (2) has a built-in isolated DC-DC module (26).

5. A novel control method of a plasma surgical device, using the novel plasma surgical device as claimed in any one of claims 1 to 4, characterized in that: The steps include: S1: The AC220V power supply from the grid is used to output +12V power to the low-voltage module through the switching power supply, and the other way is used to output +310V DC voltage through the common-mode filter and rectifier module (3) on the power board (1); S2: When the foot switch (25) is stepped on, the MCU module (8) of the main control board (2) controls the +310V voltage to be isolated and output as a digitally adjustable DC voltage VCT via the full-bridge DC / DC module (4); S3: the adjusted VCT voltage supplies power to the power amplifier circuit (5), and after being processed by the power amplifier circuit (5), a high-frequency and high-voltage square wave voltage is output to the output resonant circuit (6); S4: After resonance, a high-voltage sinusoidal voltage of a corresponding frequency is output, and then the voltage acts on human tissue through the output connection electrode (7) to achieve electrocuting or electrocoagulation operation.

6. The novel control method of plasma surgical device according to claim 5, characterized in that: In the step S2, the voltage level of the DC voltage VCT is set by a DA output module from an MCU module (8) via a PWM controller (81).

7. The novel control method of plasma surgical device according to claim 5, characterized in that: In step S4, the voltage and current signals output by the output resonant circuit (6) are sampled and converted into effective values, and then transmitted to the AD sampling module inside the MCU module (8) to realize digital sampling. The impedance and power parameters of the current load organization are calculated through the MCU module (8), and compared with the preset gear parameters. The VCT voltage is adjusted through the DA output module, so that the output power reaches the expected target value.

8. The novel control method of plasma surgical device according to claim 7, characterized in that: The VCT voltage output by the power amplifier circuit (5) in step S4 is positively correlated with the power loaded on the load structure, as follows: V vct1 / V vct0 =V p1 / V p0 =I p1 / I p0 =SQRT(P p1 / P p0 ); V vct0 : The DC voltage output by VCT at time t0; V vct1 : DC voltage output by VCT at time t1; V p0 : The effective value voltage applied to the patient at time t0; V p1 : The effective voltage applied to the patient at time t1; I p0 : The effective current loaded to the patient at time t0; I p1 : The effective current loaded to the patient at time t1; P p0 : The power loaded to the patient at time t0; P p1 : The power loaded to the patient at time t1; SQRT(): Square root function.

9. The novel control method of plasma surgical device according to claim 7, characterized in that: The output adjustment in step S4 is implemented in a segmented manner, and the electric cutting stage is controlled by a constant power and a constant voltage in parallel competition. The specific conversion is as follows: V vct1_p =V vct0 *SQRT(P p1 / P p0 ); V vct1_v =V vct0 *V p1 / V p0； V vct1_p : The VCT voltage that should be output at time t1 calculated using the constant power mode; V vct1_v : The VCT voltage that should be output at time t1 calculated using the constant voltage mode.

10. The novel control method of plasma surgical device according to claim 9, characterized in that: The step S4 compares V vct1_p With V vct1_v The absolute value between them is the smaller one, and the smaller one wins the competition and obtains the control right, and controls the DA voltage of the DA output module corresponding to the VCT voltage. The VCT voltage is proportional to the DA voltage, as shown below: V vct1 =k*V DA ; V DA : DC voltage output by DA module; k: gain coefficient.

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