Electrosurgical Generator Signal Simulation Algorithm

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Solution Overview

Problem

Existing electrosurgical generators face challenges in accurately and rapidly controlling and monitoring electrosurgical output signals due to the complex, non-ideal characteristics of power output transformers, which lead to phase shifts, frequency distortion, and increased leakage current, resulting in inadequate power regulation and potential patient safety hazards.

Innovation Solution

The implementation of mathematical simulation algorithms using input voltage and current signals from the primary winding of the transformer to accurately simulate output voltage and current signals, compensating for distortion and allowing for rapid, precise control and monitoring without the need for separate sensors on the secondary winding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If output voltage and current sensors are connected to the conductor to monitor the electrosurgical output signal, then the voltage and current characteristics can be monitored, but the sensors impose additional capacitive, resistive and inductive loads on the output signal, changing its output characteristics and increasing leakage current

Engineering Contradiction:

Improveoutput signal monitoring accuracyVSAvoidleakage current

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent uses the transformer's primary winding as an intermediary to sense the output signal characteristics indirectly. By monitoring the primary winding voltage and current and using mathematical algorithms to calculate the secondary output characteristics, the system avoids directly connecting sensors to the output conductor, thereby eliminating the additional loads and leakage current while still achieving accurate monitoring

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a mathematical model (copy) of the transformer's behavior to simulate the secondary output characteristics based on primary winding measurements. This virtual copy allows accurate monitoring of output voltage, current, and impedance without physical sensors on the output side, avoiding the harmful effects of direct sensor connection

Inventive Principle:

Principle #26Copying

2Adaptability or versatility

If the electrosurgical generator delivers power to rapidly changing tissue impedance, then the desired electrosurgical effect can be maintained, but the variable impedance causes large and instantaneous changes in current delivery, degrading or creating excess tissue damage

Engineering Contradiction:

Improvetissue impedance adaptationVSAvoidcurrent control precision

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent implements a closed-loop feedback control system that continuously monitors the primary winding voltage and current, calculates the secondary output characteristics through mathematical algorithms, and uses this information to detect impedance changes and adjust the output signal in real-time, maintaining reliable current control despite rapid tissue impedance variations

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent performs preliminary calculations of the secondary output characteristics based on primary winding measurements before actual tissue interaction occurs. By having the mathematical model ready and pre-configured, the system can immediately respond to impedance changes without delay, maintaining current control precision during rapid transitions

Inventive Principle:

Principle #10Preliminary action

3Power

If the transformer is used to deliver electrosurgical output signal, then the voltage and current can be transformed, but the non-ideal characteristics of the transformer cause phase shifts, frequency distortion, and inaccurate representation of output signals

Engineering Contradiction:

Improveelectrosurgical output powerVSAvoidoutput signal accuracy

Core Design Contradiction:

PowerVSMeasurement precision

Solution Approach 1:

The patent applies parameter changes by using mathematical algorithms to correct the phase shifts, frequency distortion, and other non-ideal transformer characteristics. The system measures the primary winding parameters and transforms them into accurate secondary output parameters through calculated corrections, maintaining both power delivery and measurement precision

Inventive Principle:

Principle #35Parameter changes

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 enables highly responsive feedback control and precise power regulation, reducing control loop lag and enhancing monitoring of tissue impedance, thereby improving the accuracy and safety of electrosurgical procedures.

Implementation Method 1

a transformer having a primary winding and a secondary winding. The secondary winding conducts the output signal. The transformer induces voltage and current signals between the primary and secondary windings

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS7736358B2Electrosurgical generator and method for simulating output signals

Publication Date: 2010.06.15 CONMED CORP

AI summary

Voltage and current of an electrosurgical output signal which is conducted by a transformer are accurately simulated by executing a simulation algorithm to compensate for inherent distortion in the values of the current and voltage induced between primary and secondary windings of the transformer. The simulation algorithm is executed in response to voltage and current signals from a primary winding of the transformer, which may be a power output transformer or part of an electrosurgical output signal sensor.