Multi-Level Inverter Control Using Datagram-Based HF Waveforms
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Solution Overview
Problem
Current electrosurgical generators with resonance converters face limitations in controlling frequency and amplitude, requiring high-speed and costly controllers for multi-level inverters, which increases bandwidth demands and operational complexity.
Innovation Solution
A multi-level inverter controlled by a datagram comprising a finite series of sequenced amplitude and frequency data vectors, reducing the need for expensive high-speed controllers and minimizing bandwidth requirements through a concise data format for generating high-frequency alternating voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If resonance converters are used for high voltage generation, then reliability is improved, but frequency and amplitude controllability deteriorates
Solution Approach 1:
The patent transforms the control approach by changing parameters from direct voltage control to frequency-based control. The control unit sends frequency information to the oscillating circuit, which then generates the reference signal. This allows frequency and amplitude to be adjusted by changing the input frequency rather than directly controlling voltage, resolving the contradiction between reliability and controllability.
2Adaptability or versatility
If multi-level inverters with high driving frequency are used, then adjustability of output signal is improved, but controller cost and complexity increases
Solution Approach 1:
The patent replaces the complex high-speed digital controller (FPGA) with an oscillating circuit that generates reference signals based on input frequency information. This substitution reduces controller complexity and cost while maintaining signal adjustability, as the oscillating circuit can generate various frequencies and amplitudes through analog or digital oscillation mechanisms rather than requiring high-speed digital processing.
Solution Approach 2:
The control strategy changes from time-domain pulse-width modulation to frequency-domain control. By controlling the output frequency rather than the timing of individual switches, the system achieves signal adjustability with a simpler controller that doesn't require high-speed processing capabilities.
3Speed
If high-speed controllers are used for multi-level inverters, then rapid changes of amplitude and frequency are possible, but bandwidth requirements and data processing demands increase
Solution Approach 1:
The patent extracts the essential control information (frequency) from complex time-domain control signals. Instead of transmitting detailed switch timing information at high speeds, only the frequency parameter needs to be communicated to the oscillating circuit, which then autonomously generates the appropriate reference signal. This extraction of essential parameters dramatically reduces bandwidth requirements and data processing demands while maintaining the ability to achieve rapid changes in amplitude and frequency.
Data Source
AI summary
Electrosurgical generator and method for outputting a high-frequency alternating voltage to an electrosurgical instrument, including an inverter that generates a high-frequency alternating voltage having variable frequency and amplitude which is fed to an output socket for the electrosurgical instrument. Ahe inverter is a multi-level inverter controlled by a reference signal defining shape of the generated HF alternating voltage, the reference signal being defined by a datagram including a finite series of sequenced amplitude and frequency data vectors for a defined number of periods. By such datagrams including descriptive data for the desired HF sinusoidal curve, data amount and bandwidth required can be reduced. Thereby a variety of modes can be described using a minimum of data which can be as low as just a few dozen bytes long. This allows for efficient control even of complex modes.