Study On Surgical System Of Radiofrequency Ablation

With the improvement of people's living standards,more and more attention is paid to medical care,and the medical equipment industry has been developed rapidly.Among them,radio frequency ablation equipment is a hot spot in various countries.Radiofrequency ablation as a modern surgical treatment,with the characteristics of fast cutting speed,good coagulation effect,simple operation and low cost,is widely used in a variety of minimally invasive surgery.A lot of foreign ablation equipment reach the frequency of MHz,however,because of the domestic technical level behind the country,the frequency of ablation equipment are mostly concentrated in the KHz.In the trend of high-frequency ablation equipment,it is very important to design an ablation system suitable for operating in ultrahigh frequency situations.The mechanism of radiofrequency ablation and the key parameters affecting the effect of electrocoagulation are introduced in this paper.According to the characteristics of these foundations,the design parameters and schemes of the system are determined.The topologies of common inverter circuits such as push-pull inverter,forward converter,half bridge inverter and full bridge inverter are analyzed and compared.The full bridge inverter topology is chosen as the main topology of RF energy generation circuit of radiofrequency ablation system.According to the requirements of adjustable output power of the system,the Buck converter circuit is selected as the power adjustment circuit of the RF power generation circuit by analyzing several modes.Combined with the advantages of traditional current source type of parallel load resonant full bridge inverter topology and voltage source type of series load resonance full bridge inverter topology,the topology of full bridge inverter circuit is improved,the input of which can absorb stray inductance,and the same bridge arm switch driving signal without setting the dead time.When the circuit with the resonance principle in proper working condition,the tube can break over with zero voltage,which can reduce the switching loss and work in the ultrahigh frequency.After analyzing the improved full-bridge inverter circuit,designing the circuit parameters and the feasibility of the scheme is verified by software simulation.Based on the improved full-bridge inverter circuit,the whole machine system is designed,including rectifier and filter circuit,Buck DC chopper,control loop circuit,energy control circuit,auxiliary power circuit and so on.The experimental results show that the design of radiofrequency ablation system based on full bridge inverter topology can achieve good electrocoagulation effect.