Electrosurgical Generator Multi-Modality Impedance Optimization
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Solution Overview
Problem
Conventional electrosurgical generators using phase-shifted full bridge resonant inverters are limited to operating in a single tissue modality due to their design, restricting their application to either vessel sealing or cutting.
Innovation Solution
An electrosurgical generator with a phase-shifted full bridge resonant inverter and a PWM controller that adjusts the frequency of PWM timing signals based on selected modalities, allowing operation in multiple tissue modalities by measuring tissue impedance and switching between different switching frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a phase-shifted full bridge resonant inverter with LCLC tank is designed for a specific tissue modality, then it achieves optimal performance for that modality, but it cannot operate in other tissue modalities
Solution Approach 1:
The patent implements dynamic switching between different tank circuits (first LCLC tank and second LCLC tank) based on the selected tissue modality. The system transitions from a static single-tank design to a dynamic multi-tank architecture, allowing the generator to adapt its resonant characteristics to match different tissue impedance requirements for various surgical modalities
Solution Approach 2:
The patent creates a universal electrosurgical generator that can perform multiple tissue modalities (vessel sealing, cutting, coagulation, etc.) by incorporating multiple LCLC tanks with different resonant frequencies. This multi-functional design eliminates the need for separate generators for each modality, allowing one system to serve multiple surgical purposes
2Adaptability or versatility
If multiple tank circuits are added to support multiple modalities, then adaptability improves, but device complexity increases
Solution Approach 1:
The patent combines multiple LCLC tank circuits into a single integrated resonant inverter system controlled by one PWM controller. Rather than using separate independent circuits for each modality, the design merges the tanks into a unified architecture where the PWM controller dynamically selects and switches between tanks, reducing overall system complexity while maintaining multi-modality capability
Solution Approach 2:
The patent changes the operating parameters (switching frequency, tank selection) based on the desired tissue modality. By adjusting the PWM frequency and selecting appropriate tanks with different resonant characteristics, the system adapts to different tissue impedances without requiring physical reconfiguration, simplifying the control mechanism while achieving versatility
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables the generator to operate in multiple modalities such as vessel sealing and electronic cutting, reducing costs by utilizing a single LCLC tank and improving surgical flexibility.
Implementation Method 1
Electrosurgical generators may use a phase-shifted full bridge resonant inverter to generate the electrosurgical energy needed to perform the electrosurgical procedure. One example of a resonant inverter uses a LCLC tank topology driven by an H-bridge
Implementation Method 2
One example of a resonant inverter uses a LCLC tank topology driven by an H-bridge having two pairs of field effect transistors (FETs)
Data Source
Figure 1
Figure 2~3
AI summary
The present disclosure is directed to an electrosurgical generator (100) including a resonant inverter (102) having an H-bridge (104) and a tank (106). The generator also includes a pulse width modulation (PWM) controller (110) configured to output PWM timing signals to the H-bridge (104). A switch (134) is configured to select a modality from among a plurality of modalities and the PWM controller (110) adjusts a frequency of the PWM timing signals based on the selected modality.