Marx Generator Pulse Control via Switch Synchronization
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Solution Overview
Problem
Marx generators face limitations in achieving high-power voltage pulses due to asynchronous switching of semiconductor switches, leading to asymmetrical voltage distribution and reduced pulse power efficiency.
Innovation Solution
Implementing a control method that measures and synchronizes the switch-on and switch-off time differences for each cell in a Marx generator, using semiconductor switches like IGBTs, to ensure simultaneous system responses and symmetrical current distribution across modules, thereby controlling the series or parallel connection of capacitors for optimized voltage pulse generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If semiconductor switches are used in Marx generator cells, then switching speed and control precision are improved, but asynchronous switching occurs leading to asymmetrical voltage distribution
Solution Approach 1:
The patent implements a feedback control system that measures the actual switching times of semiconductor switches in each cell and uses this information to adjust subsequent switching commands. This closed-loop approach compensates for timing variations and ensures synchronous switching across all cells, resolving the asymmetrical voltage distribution problem while maintaining high switching speed
Solution Approach 2:
The system performs preliminary measurement of switching time differences for each cell before the actual voltage pulse generation. Based on these pre-measured characteristics, the control unit calculates and applies appropriate time shifts to switching commands in advance, ensuring that all switches operate synchronously when the high-voltage pulse is generated
2Power
If multiple cells are connected in series to increase voltage, then output voltage is improved, but switching synchronization becomes more difficult leading to reduced efficiency
Solution Approach 1:
The patent applies individualized control to each cell based on its specific characteristics. The control unit stores switching time differences for each cell and applies cell-specific time shifts, allowing each component to operate optimally within the series-connected system. This localized approach maintains high efficiency while achieving the cumulative voltage effect of series connection
3Device complexity
If switching time differences are not compensated, then device complexity is reduced, but voltage pulse symmetry and quality deteriorate
Solution Approach 1:
The system performs preliminary measurement and characterization of each cell's switching behavior during an initialization phase. The switching time differences are stored in memory and used to pre-calculate compensation values. This preliminary action enables simple real-time compensation during operation without requiring complex real-time calculation hardware
Solution Approach 2:
The control unit acts as an intermediary that translates the measured switching time differences into appropriate time shift commands. Rather than directly modifying the switching hardware or using complex synchronization circuits, the system uses software-based time shift calculation to achieve precise synchronization with minimal additional hardware complexity
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 the generation of high-power voltage pulses with improved symmetry and efficiency, reducing downtimes and allowing for precise control of pulse characteristics suitable for medical applications like cancer treatment.
Implementation Method 1
Each cell has a capacitor for generating a voltage pulse through series connection and/or parallel connection of the capacitors
Implementation Method 2
Each cell includes a controllable semiconductor switch and a capacitor for generating a voltage pulse through series connection and/or parallel connection of the capacitors by the semiconductor switches
Data Source
AI summary
A method for controlling a pulse generator is provided. The method includes measuring a switch-on time difference for each cell and controlling the semiconductor switches of each cell for the voltage pulse as a function of the switch-on time difference. The switch-on time difference is measured between a switch-on signal for switching the respective semiconductor switch of the cell to a conducting state and a system response dependent on the switching to the conducting state. A second switch-on signal for each cell is generated in such a time-shifted manner that the system response of each cell occurs simultaneously. The system response is dependent on the switching to the conducting state.