Resonant Isolated RF Inverter for Fast Electrosurgical Power Control
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Solution Overview
Problem
Existing electrosurgical units (ESUs) face limitations in response times and accuracy, leading to potential collateral tissue damage during procedures due to inadequate control over tissue thermal effects.
Innovation Solution
The implementation of a mixed signal controller with an analog inner loop and digital outer loop, combined with a resonant isolated transformer, to regulate power delivery and maintain precise control over tissue impedance and temperature, along with a direct control topology for single-stage power conversion, reduces size, cost, and power loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional electrosurgical units are used, then tissue thermal effects can be achieved, but response times are slow and accuracy is insufficient leading to collateral tissue damage
Solution Approach 1:
The control system is segmented into dual loops: an inner feedback loop for rapid real-time adjustments and an outer loop for overall therapy management. This segmentation allows the inner loop to respond quickly to temperature changes while the outer loop maintains strategic control, resolving the contradiction between fast response time and accurate temperature control.
Solution Approach 2:
A feedback mechanism continuously monitors tissue impedance and temperature, comparing actual values with target values. The controller automatically adjusts power delivery based on this feedback, enabling precise temperature control with rapid response to prevent both underheating and overheating, thus improving both accuracy and response time.
2Power
If multi-stage power conversion is used, then power control is achieved, but device size, cost, and power loss increase
Solution Approach 1:
Multiple power conversion functions are merged into a single integrated power conversion stage. This consolidation eliminates the need for separate conversion stages, reducing device size and complexity while maintaining effective power control capability through unified management of conversion operations.
Solution Approach 2:
The single power conversion stage is designed to perform multiple functions simultaneously: voltage conversion, current regulation, and power delivery control. This multi-functionality approach maintains comprehensive power control capability while reducing the number of dedicated components, thereby decreasing device complexity and power loss.
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
This approach enhances the responsiveness and accuracy of ESUs, allowing for safer and more precise tissue treatment by minimizing collateral damage and improving therapeutic efficacy.
Implementation Method 1
The RF inverter stage comprises a resonant isolated transformer circuit configured to receive a power signal and to provide gain and filtering adjustments to the power signal
Data Source
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Figure 3A~3C
AI summary
Examples described herein may include medical devices and electrosurgical generators with resonant isolated transformers to perform filtering and gain functions. An example electrosurgical generator includes a radio frequency (RF) inverter stage configured to receive an input signal and, in response to control feedback signals, to provide an output signal that provides power to a load. The RF inverter stage includes a resonant isolated transformer configured to receive the input signal and to provide gain and filtering adjustments to the input signal to provide the output signal.