Electrosurgical Power Supply With Dual-Mode PWM Plasma Control
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Solution Overview
Problem
Existing electrosurgical systems face challenges in efficiently providing high-frequency voltage for tissue sealing with precise power control, particularly during plasma ignition and maintenance, requiring a cost-effective and safe power supply solution.
Innovation Solution
A power supply device utilizing multiple PWM stages and a transformer with a control device that switches between synchronous and staggered control modes to generate high-frequency voltage, optimizing efficiency and control accuracy during plasma ignition and maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single power supply circuit is used for both plasma ignition and maintenance, then device complexity is reduced, but it becomes difficult to optimize for both high power delivery during ignition and precise power control during maintenance
Solution Approach 1:
The power supply device dynamically switches between two control modes: synchronous control mode for plasma ignition (requiring high power) and staggered control mode for plasma maintenance (requiring precise power control). This dynamic adaptation allows a single circuit to optimize performance for both operating phases without requiring separate dedicated circuits for each phase.
Solution Approach 2:
The control device changes the control parameters of the PWM stages between operating phases. During ignition, all PWM stages are controlled synchronously with identical control signals to maximize power delivery. During maintenance, the control device switches to staggered control mode where PWM stages are controlled at different times with adjusted duty cycles to achieve precise power control and maintain plasma stability.
2Power
If multiple PWM stages are controlled synchronously, then high power is delivered for plasma ignition, but precise power control is lost during plasma maintenance
Solution Approach 1:
The control device dynamically adjusts the control strategy based on the operating phase. In synchronous control mode, all PWM stages are driven simultaneously to deliver maximum power for ignition. In staggered control mode, the control device introduces time offsets and adjusts duty cycles individually for each PWM stage, enabling precise power control during plasma maintenance while still utilizing all PWM stages for power delivery.
3Loss of energy
If a rectangular voltage waveform is used during plasma ignition, then high efficiency is achieved, but the waveform is unsuitable for precise power control during plasma maintenance
Solution Approach 1:
The power supply device dynamically adapts the output waveform characteristics to match the requirements of each operating phase. During ignition, the synchronous control of PWM stages produces a rectangular voltage waveform that maximizes power conversion efficiency. During maintenance, the staggered control mode generates a more sinusoidal waveform that enables precise power regulation while maintaining acceptable efficiency levels.
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
The solution provides efficient power supply with high efficiency during plasma ignition and precise control during maintenance, enabling compact and cost-effective operation of electrosurgical instruments.
Implementation Method 1
The transformer includes a primary side and a secondary side. A first terminal of the primary side of the transformer is electrically coupled to the common node of the multiple PWM stages... The transformer is further configured to provide a supply voltage for the electrosurgical instrument between a first connection point and a second connection point on the secondary side... an electrical output voltage that is galvanically isolated from the DC voltage source can be provided
Data Source
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AI summary
A power supply device for an electrosurgical instrument. It includes multiple operating phases. In a first operating phase, for igniting a plasma on the electrosurgical instrument, multiple PWM stages are controlled synchronously to generate a rectangular voltage waveform. In a second operating phase, for maintaining the plasma, the multiple PWM stages are controlled individually and, if necessary, with multiple switching operations per period of the output signal to be generated.