Electrosurgical Generator Impedance Compensation Control
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Solution Overview
Problem
Existing electrosurgical generators face challenges in accurately delivering energy to patients due to impedance variations in cables and other components, which affect voltage and current measurements, and lack effective methods to compensate for energy loss and leakage current.
Innovation Solution
A control system with a processor-based algorithm that determines voltage, current, and phase information to calculate the actual energy delivered to the patient, using impedance data from components like cables, and adjusts the energy output accordingly to compensate for energy loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual control of energy application is used, then the generator can deliver energy to the patient, but the reliability in achieving the intended power level deteriorates due to impedance variations in cables and components
Solution Approach 1:
The control system continuously measures the actual power delivered to the patient using voltage and current sensors, compares it with the intended power level, and automatically adjusts the generator output to compensate for energy losses in the cable and components, thereby ensuring reliable achievement of the intended power level
Solution Approach 2:
The patent replaces manual control mechanisms with an automated electronic control system that uses digital processing and algorithmic adjustment to manage energy delivery, eliminating the unreliability of manual power setting in the presence of varying impedance conditions
2Power
If high current is delivered to achieve high power output, then the energy delivery capability is improved, but the voltage drop across the cable increases due to cable resistance, worsening measurement accuracy
Solution Approach 1:
The control system uses voltage sensors to continuously monitor the actual voltage at the patient end and feeds this information back to the control algorithm, which compensates for the voltage drop caused by cable resistance, thereby maintaining accurate voltage measurement and control despite high current delivery
Solution Approach 2:
The patent introduces intermediary measurement points and sensing circuitry that directly measure voltage and current at critical locations, providing accurate data to the control system without being affected by the cable's voltage drop, thus enabling precise power control
3Power
If high voltage is delivered to achieve high power output, then the energy delivery capability is improved, but the leakage current through cable capacitance increases, worsening the actual current delivered to patient
Solution Approach 1:
The control system measures the actual current delivered to the patient using current sensors and compares it with the intended current level, then automatically adjusts the generator output to compensate for leakage current through cable capacitance, ensuring accurate current delivery despite high voltage operation
Solution Approach 2:
The patent dynamically adjusts operating parameters such as frequency and voltage waveform characteristics to minimize capacitive leakage current while maintaining effective power delivery, optimizing the balance between power output and current accuracy
4Measurement precision
If impedance of cables and components is not compensated, then the system complexity is reduced, but the accuracy of energy delivery measurement deteriorates
Solution Approach 1:
The control system implements feedback loops that automatically measure and compensate for impedance effects, eliminating the need for complex manual calibration procedures while maintaining high measurement accuracy through continuous automated adjustment
Solution Approach 2:
The system performs self-calibration and self-compensation for cable and component impedance by automatically characterizing the energy delivery path and adjusting its output, eliminating the need for external calibration equipment or complex manual setup procedures
Data Source
AI summary
A control system for use with an electrosurgical generator which delivers electrosurgical energy to tissue has a control module. The module includes a processor executing an algorithm. The algorithm has the steps of determining a sensed voltage value corresponding to a sensed voltage signal output by the electrosurgical generator and determining a sensed current value corresponding to a sensed current signal output by the electrosurgical generator. The algorithm has the steps of determining phase information corresponding to a phase shift between the voltage signal and the current signal and determining a characteristic related to the electrosurgical energy delivered to the tissue using the phase information, the sensed voltage value and the sensed current value.