Square-Wave HF Generator for Precise Electrosurgical Power Control
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Solution Overview
Problem
Existing high-frequency generators for electrosurgical instruments face challenges in accurately measuring and regulating voltage due to sinusoidal voltage, leading to potential nerve stimulation and complications like carbonization or scab formation during tissue coagulation or cutting, which can result in uncontrollable bleeding.
Innovation Solution
A high-frequency generator that converts alternating voltage to a high-frequency square-wave voltage using a transformer and a voltage conversion device, comprising a rectifier and H-bridge circuit, allowing for precise power control and measurement, thereby minimizing harmonics and power losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sinusoidal voltage is used in the high-frequency generator, then the transformer can be operated efficiently, but accurate voltage measurement and regulation become difficult leading to nerve stimulation and tissue damage
Solution Approach 1:
The patent changes the voltage waveform parameter from sinusoidal to square wave. This transformation enables accurate voltage measurement and regulation while maintaining safe operation. The square wave voltage allows for precise control of power delivery to tissue, preventing both nerve stimulation and excessive heating that could cause carbonization.
2Power
If high power components are used to achieve required voltage, then tissue treatment effectiveness is improved, but the components can only be operated digitally with hard switching causing numerous harmonics and interference
Solution Approach 1:
The patent employs periodic square wave voltage instead of continuous sinusoidal voltage. This periodic action with sharp transitions enables effective tissue treatment while the controlled switching reduces harmful harmonics. The square wave nature allows for precise duty cycle control to manage power delivery and minimize interference.
Solution Approach 2:
The patent introduces a voltage conversion device as an intermediary between the power source and the output. This device transforms the voltage waveform and enables soft switching operation, reducing harmonics and interference while maintaining the required power levels for effective tissue coagulation and cutting.
3Device complexity
If sinusoidal voltage is used, then the transformer operation is simplified, but precise power control and measurement are compromised leading to potential tissue damage
Solution Approach 1:
The patent changes the voltage waveform parameter from sinusoidal to square wave, which fundamentally improves power control precision. The square wave voltage provides clear on/off states that enable accurate measurement and regulation, allowing precise control of power delivery to tissue while maintaining manageable transformer operation through the voltage conversion device.
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 solution enables improved tissue sealing and cutting performance with reduced nerve stimulation and the risk of carbonization, allowing for more precise and controlled power delivery during electrosurgical procedures.
Implementation Method 1
a transformer (13) for coupling the primary circuit (11) to the secondary circuit (12) in a manner that is galvanically isolated from the secondary circuit (12)
Implementation Method 2
the voltage conversion device (14) comprises a rectifier (15) integrated into the secondary circuit (12) for converting the alternating voltage transmitted from the primary circuit (11) to the secondary circuit (12) by means of the transformer (13) into a rectified working voltage
Implementation Method 3
and an H-bridge circuit (16) integrated into the secondary circuit (12), to which the working voltage can be applied
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a high-frequency generator (10) comprising a primary circuit (11) to which an alternating voltage can be applied, a secondary circuit (12), a transformer (13) for coupling the primary circuit to the secondary circuit in a galvanically isolated manner, and a voltage conversion device (14) which is configured to generate a high-frequency square wave voltage from the alternating voltage transferred from the primary circuit to the secondary circuit by means of the transformer.