DC-DC Converter Voltage Limiting for Plasma Short-Circuit Protection
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Solution Overview
Problem
Traditional switch-mode DC-DC converters struggle to handle rapid and extreme changes in current and voltage due to frequent short-circuits in plasma processes, leading to potential damage and instability.
Innovation Solution
Incorporating a voltage limiting circuit, charge control unidirectional elements, and a loop-current-inhibiting element to provide stable voltage control and effective current dampening, enhancing reliability and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional switch-mode DC-DC converters are used without additional protection circuits, then the device complexity is low, but the reliability deteriorates due to damage from voltage and current spikes during short-circuits
Solution Approach 1:
The voltage limiting capacitor and charge control unidirectional element are pre-configured in the circuit to automatically activate during short-circuit conditions. The capacitor is charged during normal operation and automatically discharges to limit voltage spikes when short-circuits occur, providing preliminary protection without requiring active control during fault conditions
Solution Approach 2:
The charge control unidirectional element acts as an intermediary between the energy accumulating inductance and the voltage limiting capacitor, controlling the charge and discharge paths. This intermediary component enables automatic current management during short-circuits without requiring complex control circuits
2Reliability
If voltage limiting capacitors and charge control elements are added to protect against short-circuits, then the reliability improves, but the device complexity increases
Solution Approach 1:
The protection circuit is designed to be self-regulating through the automatic charging and discharging of the voltage limiting capacitor controlled by the charge control unidirectional element. The circuit automatically responds to short-circuit conditions without requiring external control signals or complex monitoring systems
Solution Approach 2:
The protective functions are integrated into the existing converter structure by combining the voltage limiting capacitor and charge control unidirectional element with the energy accumulating inductance and switching elements, creating a unified circuit that provides both power conversion and protection functions
3Productivity
If the converter handles frequent short-circuits in plasma processes, then the productivity is maintained, but the reliability deteriorates due to repeated voltage and current spikes
Solution Approach 1:
The voltage limiting capacitor is pre-charged during normal operation to create an energy buffer that cushions against voltage spikes during short-circuits. This beforehand cushioning allows the converter to withstand repeated short-circuit events without damage, maintaining productivity while protecting reliability
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 improves stability and reliability, reducing the risk of damage from voltage and current spikes, and potentially lowers costs by effectively managing short-circuit conditions in plasma processes.
Implementation Method 1
an energy accumulating inductance, such as an inductor... The inductor stores energy in a magnetic field when current flows through it and provides energy transfer between input and output
Implementation Method 2
a capacitor stores energy in an electric field and helps to smooth out the voltage and reduce voltage ripple in the output
Implementation Method 3
a first charge control inductance... providing a path for current when the transistor switch is off
Data Source
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AI summary
Switch-mode DC-DC-converter (100), in particular as part of a switch-mode DC-DC-pulsing-converter (180) which may be a part of a plasma power supply (80), comprising: • a positive input connection (101), • a negative input connection (103), • a positive output connection (105), • a negative output connection (107), • a first energy accumulating inductance (111), • a first power control switching element (113), e.g., a transistor, • a first free-wheeling unidirectional element (115), e.g., a diode, • a first voltage limiting capacitor (117), • a first charge control unidirectional element (119), e.g., a diode, and • a first charge control inductance (116), and wherein the first energy accumulating inductance (111), the first power control switching element (113), and the first free-wheeling unidirectional element (115) are connected together with their respective first end in a first star-point-connection (110) and, with their respective second end, to one of the input and/or output connections, and wherein the first voltage limiting capacitor (117) and the charge control unidirectional element (119) connected together in an additional star-point-connection (120) and, on their other end, to one of the input and/or output connections, and wherein the first charge control inductance (116) is connected to the additional star-point-connection (120) and to a voltage reference point, e.g., the first star-point-connection (110) or one of the input and/or output connections.