阅读说明：本技术 一种基于频率及功率跟踪的超声手术刀系统及其控制方法 (ultrasonic scalpel system based on frequency and power tracking and control method thereof ) 是由 刘富春 王松波 于 2019-07-29 设计创作，主要内容包括：本发明公开了一种基于频率及功率跟踪的超声手术刀系统及其控制方法,该超声手术刀系统包括主控MCU、基于DDS的信号发生控制模块、功率输出隔离模块、交互模块、医用开关电源,所述信号发生控制模块使用DDS芯片生成两路高精度、特定频率的PWM信号,通过基于时钟电路的数控半桥功率调整电路对功率进行控制；所述功率隔模块通过串联功率电感使感抗匹配,为超声刀具提供接口,并分别使用PID算法和ADRC算法实时控制功率输出和超声手术刀工作频率,达到对功率的实时控制和对谐振点频率的跟随控制。本发明具有控制精度高、响应速度块、手术效果好、能量利用率高、便于操作等优点,适用于在常见超声外科手术中驱动超声外科手术刀设备。(The invention discloses an ultrasonic scalpel system based on frequency and power tracking and a control method thereof, wherein the ultrasonic scalpel system comprises a master control MCU, a signal generation control module based on a DDS (direct digital synthesizer), a power output isolation module, an interaction module and a medical switching power supply, wherein the signal generation control module uses a DDS chip to generate two paths of PWM (pulse width modulation) signals with high precision and specific frequency, and controls the power through a numerical control half-bridge power adjusting circuit based on a clock circuit; the power isolation module enables inductive reactance to be matched through series connection of power inductors, provides an interface for the ultrasonic knife, and controls power output and the working frequency of the ultrasonic scalpel in real time by respectively using a PID algorithm and an ADRC algorithm, so that real-time control over power and follow-up control over resonant point frequency are achieved. The invention has the advantages of high control precision, high response speed, good operation effect, high energy utilization rate, convenient operation and the like, and is suitable for driving the ultrasonic surgical scalpel equipment in common ultrasonic surgical operations.)

1. An ultrasonic surgical blade system based on frequency and power tracking, comprising:

the signal generation control module is used for generating two paths of complementary PWM signals with high precision frequency by receiving an instruction of the main control MCU, reducing the duty ratio of the PWM signals according to target frequency, then carrying out power amplification on the signals, driving the push-pull circuit to be alternately conducted, leading the direct current signals to be in push-pull conduction, and transmitting the signals to the power driving isolation module through the high-frequency transformer;

a power output isolation module for resonating the transducer within an operating frequency range; collecting the amplitude and phase of current and voltage at the same time, processing and transmitting to the master control MCU;

the main control MCU is used for sending an instruction to the signal generation control module to generate two paths of complementary PWM signals with high precision frequency, receiving data acquired by the power output isolation module and comparing the data with the reference input of the system, realizing real-time accurate tracking control of output power and working frequency through a PID control algorithm and an ADRC control algorithm respectively, correspondingly adjusting the control instruction and finally realizing closed-loop automatic control of the system;

The interaction module is used for setting power and volume and outputting relevant state information when the equipment runs;

The medical switching power supply is used for providing a direct current power supply with corresponding voltage for each module.

2. the ultrasonic surgical blade system based on frequency and power tracking according to claim 1, wherein the signal generation control module comprises:

The signal generating circuit receives an instruction sent by the master control MCU through a DDS chip with the regulation precision of 0.1Hz, generates a square wave with the duty ratio of 50 percent and high-precision target frequency, and obtains two paths of complementary PWM signals through the action of a gate circuit;

the numerical control half-bridge power adjusting circuit comprises a numerical control potentiometer and a digital clock, wherein the resistance value of the numerical control potentiometer accessed to the digital clock circuit is controlled through a main control MCU (micro control unit), the frequency and the duty ratio of a generated reference clock signal are adjusted, the duty ratios of original two paths of complementary PWM (pulse width modulation) are changed through a trigger circuit, and then the power is adjusted;

The driving power amplifier circuit is used for improving the amplitude of the PWM signal so as to drive the push-pull output circuit to work;

and the push-pull MOSFET is used for enabling the +48V direct-current power supply to be in push-pull conduction, further enabling the transformer to work and transmitting the signal to the power driving isolation module.

3. the frequency and power tracking based ultrasonic surgical blade system of claim 1, wherein the power output isolation module comprises:

the power inductor is used for carrying out impedance matching with the ultrasonic transducer so that the transducer can work in a resonant mode near a rated frequency;

the feedback circuit divides voltage through a series-parallel resistance network, uses a multi-stage operational amplifier structure to continuously sample the current and the voltage of the working circuit, wherein the first stage output is directly transmitted to the master control MCU for detecting the signal amplitude, the second stage output is transmitted to the voltage comparison circuit, the comparison circuit compares the current and voltage signals with zero potential, outputs two paths of complementary PWM signals and transmits the two paths of complementary PWM signals to the master control MCU for detecting the phase difference between the current and the voltage in real time;

The ultrasonic scalpel interface circuit is used for providing a standard power interface for ultrasonic scalpel equipment, providing an accurate electric signal to drive the ultrasonic transducer to work, and further enabling the scalpel to enter a high-frequency vibration state;

and the key detection circuit is used for detecting the state of a trigger switch on the ultrasonic knife equipment, transmitting the corresponding level to the master control MCU and further controlling the working state of the ultrasonic scalpel equipment.

4. The ultrasonic surgical knife system based on frequency and power tracking according to claim 3, wherein the master MCU detects the phase difference between the current and the voltage in real time through an external timer.

5. the ultrasonic surgical blade system based on frequency and power tracking of claim 3, wherein the interaction module comprises:

The key interaction module detects the state of the independent key by using the key detection chip and transmits the key pressing information to the main control MCU by using the serial port;

The nixie tube interaction module receives a display instruction sent by the main control MCU by using a nixie tube driving chip and drives relevant state information of corresponding nixie tube display equipment during operation;

and the loudspeaker interaction module receives an output instruction sent by the main control MCU by using a loudspeaker driving chip, reads the audio file at the corresponding position from the FLASH chip, and drives the loudspeaker to output a corresponding audio signal after the operational amplifier of the loudspeaker driving chip.

6. the ultrasonic surgical blade system based on frequency and power tracking according to claim 3, wherein the medical switching power supply provides a DC power supply of +48V, +12V, -12V, +5V to each module.

7. the ultrasonic scalpel system based on frequency and power tracking of claim 1, wherein when the real-time accurate tracking control of the output power is realized through a PID control algorithm, the reference power is used as the input of a control system, the power is calculated by using the amplitude values of the acquired voltage and current as feedback information, and the accurate control of the power is realized by reducing the deviation value after being compared with the reference input;

when the real-time accurate tracking control of the working frequency is realized through the ADRC control algorithm, the phase difference of the operating knife at the resonance point is used as the target of the system and is input into a tracking differentiator of an ADRC control system, an extended state observer is used for observing the phase difference and the phase difference change rate of the voltage and the current of the working point in real time and observing disturbance in real time, and a state error feedback control law is used for carrying out control and disturbance compensation according to the phase error and the phase change rate error, so that the real-time control of the working frequency is finally realized.

8. a control method of an ultrasonic scalpel system based on frequency and power tracking is characterized by comprising the following steps:

step 1, initializing hardware equipment:

After the medical switching power supply is connected with alternating current, a hardware platform is powered on, and hardware functions are initialized;

step 2, detecting the access and the state of the ultrasonic cutter:

Judging whether a driving electric signal is generated or not by detecting the access state of the ultrasonic knife, acquiring the current of an interface circuit of the ultrasonic scalpel through a feedback circuit of a power output isolation module, if the current is in a normal range, accessing the knife and having a good state, and carrying out frequency sweep detection on the resonance point of the ultrasonic knife; if the current is not in the normal working range, the system does not access the cutter or the ultrasonic cutter is abnormal in state, corresponding information is prompted, and the ultrasonic cutter is waited to be inserted or replaced;

step 3, detecting the working resonance point of the ultrasonic cutter by frequency sweeping:

the method comprises the steps that the capture of a resonance working point is realized through frequency sweep operation, a master control MCU enables a signal generation circuit and a numerical control half-bridge power adjusting circuit of a signal generation control module, a regulation instruction is continuously sent to a DDS chip of the signal generation circuit, so that an output signal is subjected to frequency sweep operation with the step length of 0.1Hz within the working frequency range of a transducer, the master control MCU records the amplitude and the phase of current and voltage in a cutter interface circuit under each frequency, the frequency point when the phase difference is zero and the circuit power is maximum is selected as the no-load resonance frequency of the current ultrasonic cutter, the frequency sweep detection is finished, the ultrasonic cutter firstly works at the no-load resonance frequency, and then the tracking control of the resonance point is carried out when a load is accessed;

And step 4, entering a working state:

Initializing and outputting related hardware modules, and starting the system to enter a working state; the loudspeaker and the nixie tube display equipment perform corresponding initialization output to prompt a user that the ultrasonic scalpel equipment system can be used; the main control MCU realizes the display of specific power or the voice broadcast of the power by detecting the states of keys in the interactive module and the keys on the ultrasonic cutter equipment; when a key is pressed down on the ultrasonic cutter equipment, the main control MCU generates a driving electric signal with no-load resonance frequency through control, the power of the system is set to meet the requirement, the ultrasonic cutter is driven to start to enter a working state, and meanwhile, the ADC voltage and current acquisition function and the timer are used for detecting the current, the amplitude and the phase of the voltage of the ultrasonic cutter interface circuit in real time; when the load of the ultrasonic cutter changes or the environment changes, the phase and amplitude parameters of the voltage and the current of the interface circuit can deviate from the reference values, when the feedback system detects the deviation, the PID control algorithm is used for controlling the signal generating circuit to realize the accurate tracking of the output power, and meanwhile, the ADRC control algorithm is used for controlling the direct digital frequency synthesizer to adjust the working frequency in time, so that the ultrasonic cutter works in a resonance state, and the closed-loop control of the system is ensured;

And 5, closing the system: when the equipment system is closed, the equipment system is powered down by disconnecting the medical power switch so as to close the system.

9. The method of controlling an ultrasonic surgical blade system based on frequency and power tracking according to claim 8,

in step 1, the initializing a hardware function specifically includes: initializing communication interfaces of circuits in the signal generating circuit, the numerical control half-bridge power adjusting circuit and the interactive module, communicating with related chips to reset the communication interfaces, and initializing ADC and timer hardware to prepare for respectively collecting the amplitude and phase of an electric signal transmitted by the feedback measuring circuit.

10. The method of controlling a frequency and power tracking based ultrasonic surgical blade system according to claim 8, wherein the step 4 further comprises:

when the trigger key is released, the main control MCU sends an instruction to enable the DDS chip to enter a sleep state, and the equipment system stops generating an electric signal; when the trigger key is pressed down again, the main control MCU control system outputs the driving signal with no-load frequency again, and the process is repeated.

Technical Field

the invention relates to an ultrasonic scalpel system, in particular to an ultrasonic scalpel system based on frequency and power tracking and a control method thereof, which are used for driving a scalpel head to stably work at a resonance point.

background

the ultrasonic technology is a discipline with extremely strong comprehensiveness, and relates to a plurality of fields such as electronics, acoustics, materials, machinery, medical treatment and the like. An ultrasonic scalpel is one of medical instruments commonly used in surgical operations, and the operating principle of the ultrasonic scalpel is that an ultrasonic transducer is driven to convert electric energy into mechanical energy, the scalpel is driven to vibrate at a resonance frequency point at a high frequency, water in tissues is vaporized, protein hydrogen bonds are broken and denatured, cells are disintegrated, the tissues are cut or coagulated, and blood coagulation and hemostasis are performed during tissue separation and tissue cutting. The medical instrument has the advantages of less bleeding during operation, quick postoperative recovery and no trace, and has good reverberation and wide application in the medical field.

The ultrasonic scalpel equipment is formed by combining an ultrasonic power supply generating device and an ultrasonic scalpel. The ultrasonic scalpel mainly comprises an ultrasonic transducer, a scalpel head and a trigger circuit, and is connected to an ultrasonic power supply generating device through a connecting wire and a plug so as to obtain a driving signal for driving the scalpel head to work. As a core component of the ultrasonic scalpel equipment, the ultrasonic power supply generating device outputs an alternating current signal within a rated frequency range when the trigger button is pressed down, and drives the transducer to convert electric energy into mechanical energy, so that the scalpel head generates high-frequency vibration.

Because the access impedance characteristic of the ultrasonic transducer can change along with the change of mechanical load applied by the transducer, when the ultrasonic scalpel is loaded with different tool bits, acts on different objects or different parts, the resonant frequency of the ultrasonic scalpel can also change, if the frequency of an electric signal output by the power supply generating device is not adjusted in time, the transducer works in a resonant state, the tool bit can be damaged after a long time, and the quality and the effect of the operation are influenced.

at present, the power supply generating devices of a plurality of ultrasonic scalpel devices adopt open-loop control on the output of frequency and power, so that the working frequency of a scalpel and the output power of the device cannot be effectively tracked and controlled, and part of the ultrasonic scalpel devices can realize frequency tracking control. When the ultrasonic scalpel is provided with different scalpel heads or the circuit structure of the ultrasonic power supply generating device is different, the optimal adjusting parameter of the system can be correspondingly changed, and the problems of not high adjusting speed, large overshoot and low adjusting precision of frequency tracking control cannot be effectively solved by using a PID control algorithm. The problems all cause adverse effects on the frequency tracking performance of the power supply driving system of the ultrasonic scalpel, greatly reduce the service life of the ultrasonic scalpel and reduce the medical effect of the operation.

Therefore, it is one of the key issues in the related research field to effectively track and accurately control the frequency and power output by the power driving system of the ultrasonic scalpel.

disclosure of Invention

Based on the current situation and the problems, the invention provides the ultrasonic scalpel system based on frequency and power tracking and the control method thereof, which can effectively track the frequency and power output by the power supply driving system of the ultrasonic scalpel, realize accurate control and improve the service life of the ultrasonic scalpel and the medical effect of surgery.

The purpose of the invention is realized by at least one of the following technical schemes:

an ultrasonic surgical blade system based on frequency and power tracking, comprising:

The signal generation control module is used for generating two paths of complementary PWM signals with high precision frequency by receiving an instruction of the main control MCU, reducing the duty ratio of the PWM signals according to target frequency, then carrying out power amplification on the signals, driving the push-pull circuit to be alternately conducted, leading the direct current signals to be in push-pull conduction, and transmitting the signals to the power driving isolation module through the high-frequency transformer;

A power output isolation module for resonating the transducer within an operating frequency range; collecting the amplitude and phase of current and voltage at the same time, processing and transmitting to the master control MCU;

The main control MCU is used for sending an instruction to the signal generation control module to generate two paths of complementary PWM signals with high precision frequency, receiving data acquired by the power output isolation module and comparing the data with the reference input of the system, realizing real-time accurate tracking control of output power and working frequency through a PID control algorithm and an ADRC control algorithm respectively, correspondingly adjusting the control instruction and finally realizing closed-loop automatic control of the system;

The interaction module is used for setting power and volume and outputting relevant state information when the equipment runs;

the medical switching power supply is used for providing a direct current power supply with corresponding voltage for each module.

further, the signal generation control module comprises:

The signal generating circuit receives an instruction sent by the master control MCU through a DDS chip with the regulation precision of 0.1Hz, generates a square wave with the duty ratio of 50 percent and high-precision target frequency, and obtains two paths of complementary PWM signals through the action of a gate circuit;

the numerical control half-bridge power adjusting circuit comprises a numerical control potentiometer and a digital clock, wherein the resistance value of the numerical control potentiometer accessed to the digital clock circuit is controlled through a main control MCU (micro control unit), the frequency and the duty ratio of a generated reference clock signal are adjusted, the duty ratios of original two paths of complementary PWM (pulse width modulation) are changed through a trigger circuit, and then the power is adjusted;

the driving power amplifier circuit is used for improving the amplitude of the PWM signal so as to drive the push-pull output circuit to work;

and the push-pull MOSFET is used for enabling the +48V direct-current power supply to be in push-pull conduction, further enabling the transformer to work and transmitting the signal to the power driving isolation module.

Further, the power output isolation module comprises:

the power inductor is used for carrying out impedance matching with the ultrasonic transducer so that the transducer can work in a resonant mode near a rated frequency;

the feedback circuit divides voltage through a series-parallel resistance network, uses a multi-stage operational amplifier structure to continuously sample the current and the voltage of the working circuit, wherein the first stage output is directly transmitted to the master control MCU for detecting the signal amplitude, the second stage output is transmitted to the voltage comparison circuit, the comparison circuit compares the current and voltage signals with zero potential, outputs two paths of complementary PWM signals and transmits the two paths of complementary PWM signals to the master control MCU for detecting the phase difference between the current and the voltage in real time;

the ultrasonic scalpel interface circuit is used for providing a standard power interface for ultrasonic scalpel equipment, providing an accurate electric signal to drive the ultrasonic transducer to work, and further enabling the scalpel to enter a high-frequency vibration state;

And the key detection circuit is used for detecting the state of a trigger switch on the ultrasonic knife equipment, transmitting the corresponding level to the master control MCU and further controlling the working state of the ultrasonic scalpel equipment.

further, the master control MCU detects the phase difference between the current and the voltage in real time through an external timer.

further, the interaction module comprises:

the key interaction module detects the state of the independent key by using the key detection chip and transmits the key pressing information to the main control MCU by using the serial port;

the nixie tube interaction module receives a display instruction sent by the main control MCU by using a nixie tube driving chip and drives relevant state information of corresponding nixie tube display equipment during operation;

and the loudspeaker interaction module receives an output instruction sent by the main control MCU by using a loudspeaker driving chip, reads the audio file at the corresponding position from the FLASH chip, and drives the loudspeaker to output a corresponding audio signal after the operational amplifier of the loudspeaker driving chip.

further, the medical switching power supply provides +48V, +12V, -12V, +5V direct current power supply for each module.

Furthermore, when the real-time accurate tracking control of the output power is realized through a PID control algorithm, the reference power is used as the input of a control system, the power is calculated by utilizing the amplitude values of the acquired voltage and current and is used as feedback information, and the accurate control of the power is realized by reducing the deviation value after being compared with the reference input;

when the real-time accurate tracking control of the working frequency is realized through the ADRC control algorithm, the phase difference of the operating knife at the resonance point is used as the target of the system and is input into a tracking differentiator of an ADRC control system, an extended state observer is used for observing the phase difference and the phase difference change rate of the voltage and the current of the working point in real time and observing disturbance in real time, and a state error feedback control law is used for carrying out control and disturbance compensation according to the phase error and the phase change rate error, so that the real-time control of the working frequency is finally realized.

A control method of an ultrasonic scalpel system based on frequency and power tracking comprises the following steps:

step 1, initializing hardware equipment:

After the medical switching power supply is connected with alternating current, a hardware platform is powered on, and hardware functions are initialized;

step 2, detecting the access and the state of the ultrasonic cutter:

judging whether a driving electric signal is generated or not by detecting the access state of the ultrasonic knife, acquiring the current of an interface circuit of the ultrasonic scalpel through a feedback circuit of a power output isolation module, if the current is in a normal range, accessing the knife and having a good state, and carrying out frequency sweep detection on the resonance point of the ultrasonic knife; if the current is not in the normal working range, the system does not access the cutter or the ultrasonic cutter is abnormal in state, corresponding information is prompted, and the ultrasonic cutter is waited to be inserted or replaced;

step 3, detecting the working resonance point of the ultrasonic cutter by frequency sweeping:

the method comprises the steps that the capture of a resonance working point is realized through frequency sweep operation, a master control MCU enables a signal generation circuit and a numerical control half-bridge power adjusting circuit of a signal generation control module, a regulation instruction is continuously sent to a DDS chip of the signal generation circuit, so that an output signal is subjected to frequency sweep operation with the step length of 0.1Hz within the working frequency range of a transducer, the master control MCU records the amplitude and the phase of current and voltage in a cutter interface circuit under each frequency, the frequency point when the phase difference is zero and the circuit power is maximum is selected as the no-load resonance frequency of the current ultrasonic cutter, the frequency sweep detection is finished, the ultrasonic cutter firstly works at the no-load resonance frequency, and then the tracking control of the resonance point is carried out when a load is accessed;

And step 4, entering a working state:

initializing and outputting related hardware modules, and starting the system to enter a working state; the loudspeaker and the nixie tube display equipment perform corresponding initialization output to prompt a user that the ultrasonic scalpel equipment system can be used; the main control MCU realizes the display of specific power or the voice broadcast of the power by detecting the states of keys in the interactive module and the keys on the ultrasonic cutter equipment; when a key is pressed down on the ultrasonic cutter equipment, the main control MCU generates a driving electric signal with no-load resonance frequency through control, the power of the system is set to meet the requirement, the ultrasonic cutter is driven to start to enter a working state, and meanwhile, the ADC voltage and current acquisition function and the timer are used for detecting the current, the amplitude and the phase of the voltage of the ultrasonic cutter interface circuit in real time; when the load of the ultrasonic cutter changes or the environment changes, the phase and amplitude parameters of the voltage and the current of the interface circuit can deviate from the reference values, when the feedback system detects the deviation, the PID control algorithm is used for controlling the signal generating circuit to realize the accurate tracking of the output power, and meanwhile, the ADRC control algorithm is used for controlling the direct digital frequency synthesizer to adjust the working frequency in time, so that the ultrasonic cutter works in a resonance state, and the closed-loop control of the system is ensured;

and 5, closing the system: when the equipment system is closed, the equipment system is powered down by disconnecting the medical power switch so as to close the system.

further, in step 1, the initializing the hardware function specifically includes: initializing communication interfaces of circuits in the signal generating circuit, the numerical control half-bridge power adjusting circuit and the interactive module, communicating with related chips to reset the communication interfaces, and initializing ADC and timer hardware to prepare for respectively collecting the amplitude and phase of an electric signal transmitted by the feedback measuring circuit.

further, the step 4 further includes:

when the trigger key is released, the main control MCU sends an instruction to enable the DDS chip to enter a sleep state, and the equipment system stops generating an electric signal; when the trigger key is pressed down again, the main control MCU control system outputs the driving signal with no-load frequency again, and the process is repeated.

Compared with the prior art, the ultrasonic scalpel has the advantages that on the basis of realizing effective isolation of the driving signal and the electric signal, the phase and the amplitude of the acquired driving signal are used as feedback information of the system by using the precise sensing element, and a high-precision control algorithm is combined, so that when the load state of the ultrasonic scalpel changes, the frequency of the output electric signal can be timely adjusted with the adjusting precision of 0.1Hz, the ultrasonic transducer is maintained in a resonance state, and the output power is stabilized. Therefore, the invention has the advantages of short adjusting time, small system overshoot, high adjusting precision, high response speed, strong environmental adaptability, good operation effect, high energy utilization rate, convenient operation, high system safety and the like, and is widely suitable for driving the ultrasonic surgical scalpel equipment in common ultrasonic surgical operations.

drawings

fig. 1 is an overall configuration diagram of an ultrasonic surgical blade system according to an embodiment of the present invention.

FIG. 2 is a flow chart of PID power control of the ultrasonic surgical blade system according to an embodiment of the invention.

fig. 3 is a flow chart of the ADRC frequency control of the ultrasonic surgical blade system according to an embodiment of the present invention.

fig. 4 is a block diagram of a signal generation control circuit of the ultrasonic scalpel system according to the embodiment of the present invention.

Fig. 5 is a schematic diagram of output signals of a signal generating circuit and a power adjusting circuit of an ultrasonic scalpel system according to an embodiment of the present invention.

Fig. 6 is a circuit diagram of a power output isolation module of the ultrasonic scalpel system according to the embodiment of the invention.

Fig. 7 is a flowchart of a control method according to an embodiment of the invention.

Detailed Description

the invention is further described below with reference to the figures and examples.

as shown in fig. 1, an ultrasonic scalpel system based on frequency and power tracking comprises:

The signal generation control module is used for generating two paths of complementary PWM signals with high precision frequency by receiving an instruction of the main control MCU, reducing the duty ratio of the PWM signals according to target frequency, then carrying out power amplification on the signals, driving the push-pull circuit to be alternately conducted, leading the direct current signals to be in push-pull conduction, and transmitting the signals to the power driving isolation module through the high-frequency transformer;

a power output isolation module for resonating the transducer within an operating frequency range; collecting the amplitude and phase of current and voltage at the same time, processing and transmitting to the master control MCU;

The main control MCU is based on STM32F407 and is used for sending an instruction to the signal generation control module to generate two paths of complementary PWM signals with high precision frequency, receiving data acquired by the power output isolation module and comparing the data with reference input of a system, realizing real-time accurate tracking control of output power and working frequency through a PID control algorithm and an ADRC control algorithm respectively, carrying out corresponding adjustment on the control instruction and finally realizing closed-loop automatic control of the system;

The interaction module is used for setting power and volume and outputting relevant state information when the equipment runs;

the medical switching power supply is used for providing a direct current power supply with corresponding voltage for each module, providing a direct current power supply with +48V, +12V, -12V and +5V for each module, and improving the practicability of the system.

specifically, as shown in fig. 4, the signal generation control module includes:

The signal generating circuit receives an instruction sent by the master control MCU through a DDS chip with the regulation precision of 0.1Hz, generates a square wave with the duty ratio of 50 percent and high-precision target frequency, and obtains two paths of complementary PWM signals through the action of a gate circuit;

the numerical control half-bridge power adjusting circuit comprises a numerical control potentiometer and a digital clock, wherein the resistance value of the numerical control potentiometer accessed to the digital clock circuit is controlled through a main control MCU (micro control unit), the frequency and the duty ratio of a generated reference clock signal are adjusted, the duty ratios of two original paths of complementary PWM (pulse width modulation) are changed through a trigger circuit, and then the power is adjusted, wherein the waveform is shown in figure 5;

the driving power amplifier circuit is used for improving the amplitude of the PWM signal so as to drive the push-pull output circuit to work;

And the push-pull MOSFET is used for enabling the +48V direct-current power supply to be in push-pull conduction, further enabling the transformer to work and transmitting the signal to the power driving isolation module.

It should be understood that, in the signal generation control module, the signal generation circuit generates two complementary PWM signals with high precision frequency by receiving the instruction of the main control MCU. And the PWM signal passes through the numerical control half-bridge power adjusting circuit, and the duty ratio of the PWM signal is reduced according to the target frequency. The processed signals are subjected to power amplification through a power amplification circuit and then used for driving a push-pull circuit to be alternately conducted, so that the direct current +48V signals are in push-pull conduction, and the signals are transmitted to a power driving isolation module through a high-frequency transformer.

Specifically, as shown in fig. 6, the power output isolation module includes:

the power inductor is used for carrying out impedance matching with the ultrasonic transducer so that the transducer can work in a resonant mode near a rated frequency;

The feedback circuit divides voltage through a series-parallel resistance network, a multi-stage operational amplifier structure is used for continuously sampling current and voltage of a working circuit, wherein the first-stage output is directly transmitted to the master control MCU and used for detecting signal amplitude, the second-stage output is transmitted to the voltage comparison circuit, the comparison circuit compares current and voltage signals with zero potential, outputs two paths of complementary PWM signals and transmits the two paths of complementary PWM signals to the master control MCU, and the master control MCU detects the phase difference between the current and the voltage in real time through an external timer;

the ultrasonic scalpel interface circuit is used for providing a standard power interface for ultrasonic scalpel equipment, providing an accurate electric signal to drive the ultrasonic transducer to work, and further enabling the scalpel to enter a high-frequency vibration state;

And the key detection circuit is used for detecting the state of a trigger switch on the ultrasonic knife equipment, transmitting the corresponding level to the master control MCU and further controlling the working state of the ultrasonic scalpel equipment.

it should be appreciated that the power output isolation module is connected to the secondary side of the transformer, wherein the ultrasonic blade interface is impedance matched to the ultrasonic transducer by a series power inductor, enabling the transducer to resonate within the operating frequency range. Meanwhile, the power output isolation module is also provided with a feedback measurement circuit, a high-precision sensor is used for collecting the amplitude and the phase of the current and the voltage of the cutter interface circuit, the amplitude and the phase are transmitted to the main control MCU after being processed, and are compared with the reference input of the system, corresponding adjustment is carried out on a control instruction, real-time tracking of the output power and the working frequency is realized, and finally, the closed-loop automatic control of the system is realized.

specifically, the interaction module includes:

the key interaction module detects the state of the independent key by using the key detection chip and transmits the key pressing information to the main control MCU by using the serial port;

the nixie tube interaction module receives a display instruction sent by the main control MCU by using a nixie tube driving chip and drives relevant state information of corresponding nixie tube display equipment during operation;

and the loudspeaker interaction module receives an output instruction sent by the main control MCU by using a loudspeaker driving chip, reads the audio file at the corresponding position from the FLASH chip, and drives the loudspeaker to output a corresponding audio signal after the operational amplifier of the loudspeaker driving chip.

It should be understood that, a key circuit is designed in the interaction module, so that a user can set the output of the system accordingly, and hierarchical output of power can be realized through keys. The module is also provided with a liquid crystal nixie tube for displaying the set power and the real-time working frequency, and a loudspeaker for realizing voice broadcast of the power. The whole interaction process is realized by accurate data communication between the main control MCU and the corresponding control chip.

As shown in fig. 2, when the real-time accurate tracking control of the output power is realized by the PID control algorithm, the reference power is used as the input of the control system, the power is calculated by using the amplitude values of the collected voltage and current as the feedback information, and the accurate control of the power is realized by reducing the deviation after comparing with the reference input;

The PID control algorithm has the obvious defects in the real-time performance of the tracking of the working frequency because the response speed of the PID control algorithm to the input interference of the system is low and the compensation control cannot be realized in time.

specifically, as shown in fig. 3, when the real-time accurate tracking control of the working frequency is realized through the ADRC control algorithm, the phase difference of the scalpel working at the resonance point is input into a tracking differentiator of the ADRC control system as a target of the system, the phase difference and the phase difference change rate of the voltage and the current of the working point and the real-time observation of the disturbance are observed in real time by using the extended state observer, and the state error feedback control law performs control and disturbance compensation according to the phase error and the phase change rate error, so as to finally realize the real-time control of the working frequency.

The embodiment realizes real-time tracking and accurate control of the output power and the working frequency of the system through a high-precision device and a high-precision control algorithm respectively.

as shown in fig. 7, a method for controlling an ultrasonic scalpel system based on frequency and power tracking includes the steps of:

step 1, initializing hardware equipment:

After the medical switching power supply is connected with 220V alternating current, the hardware platform is powered on, and the hardware function is initialized, which specifically comprises the following steps: initializing communication interfaces of circuits in the signal generating circuit, the numerical control half-bridge power adjusting circuit and the interactive module, communicating with related chips to reset the communication interfaces, and initializing ADC (analog to digital converter) and timer hardware to prepare for respectively collecting the amplitude and phase of an electric signal transmitted by the feedback measuring circuit;

Step 2, detecting the access and the state of the ultrasonic cutter:

judging whether a driving electric signal is generated or not by detecting the access state of the ultrasonic knife, acquiring the current of an interface circuit of the ultrasonic scalpel through a feedback circuit of a power output isolation module, if the current is in a normal range, accessing the knife and having a good state, and carrying out frequency sweep detection on the resonance point of the ultrasonic knife; if the current is not in the normal working range, the system does not access the cutter or the ultrasonic cutter is abnormal in state, corresponding information is prompted, and the ultrasonic cutter is waited to be inserted or replaced;

step 3, detecting the working resonance point of the ultrasonic cutter by frequency sweeping:

the method comprises the steps that the capture of a resonance working point is realized through frequency sweep operation, a master control MCU enables a signal generation circuit and a numerical control half-bridge power adjusting circuit of a signal generation control module, a regulation instruction is continuously sent to a DDS chip of the signal generation circuit, so that an output signal is subjected to frequency sweep operation with the step length of 0.1Hz within the working frequency range of a transducer, the master control MCU records the amplitude and the phase of current and voltage in a cutter interface circuit under each frequency, the frequency point when the phase difference is zero and the circuit power is maximum is selected as the no-load resonance frequency of the current ultrasonic cutter, the frequency sweep detection is finished, the ultrasonic cutter firstly works at the no-load resonance frequency, and then the tracking control of the resonance point is carried out when a load is accessed;

And step 4, entering a working state:

Initializing and outputting related hardware modules, and starting the system to enter a working state; the loudspeaker and the nixie tube display equipment perform corresponding initialization output to prompt a user that the ultrasonic scalpel equipment system can be used; the main control MCU realizes the display of specific power or the voice broadcast of the power by detecting the states of keys in the interactive module and the keys on the ultrasonic cutter equipment; when a key is pressed down on the ultrasonic cutter equipment, the main control MCU generates a driving electric signal with no-load resonance frequency through control, the power of the system is set to meet the requirement, the ultrasonic cutter is driven to start to enter a working state, and meanwhile, the ADC voltage and current acquisition function and the timer are used for detecting the current, the amplitude and the phase of the voltage of the ultrasonic cutter interface circuit in real time; when the load of the ultrasonic cutter changes or the environment changes, the phase and amplitude parameters of the voltage and the current of the interface circuit can deviate from the reference values, when the feedback system detects the deviation, the PID control algorithm is used for controlling the signal generating circuit to realize the accurate tracking of the output power, and meanwhile, the ADRC control algorithm is used for controlling the direct digital frequency synthesizer to adjust the working frequency in time, so that the ultrasonic cutter works in a resonance state, and the closed-loop control of the system is ensured; when the trigger key is released, the main control MCU sends an instruction to enable the DDS chip to enter a sleep state, and the equipment system stops generating an electric signal; when the trigger key is pressed down again, the main control MCU control system outputs the driving signal with no-load frequency again, and the process is repeated.

And 5, closing the system: when the equipment system is closed, the equipment system is powered down by disconnecting the medical power switch so as to close the system.

The invention can be applied to surgical ultrasonic scalpel equipment, has higher precision in the aspects of power output and output working frequency tracking control, particularly in the aspect of tracking control of the working frequency of an ultrasonic scalpel, not only uses a DDS chip with the adjustment precision of 0.1Hz, but also uses an ADRC control algorithm with extremely high control precision and response speed, and realizes accurate tracking control of the working frequency of a system. The invention has the advantages of short adjusting time, small system overshoot, high adjusting precision, strong environmental adaptability, high system safety and the like.

the above description is only for the preferred embodiment of the present invention, and is not intended to limit the present invention in any way, and all simple modifications, equivalent changes and modifications made to the above embodiment according to the technical spirit of the present invention are within the scope of the technical solution of the present invention.