High-Power DC Switch with Anti-Series Transistors and Resistor
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Solution Overview
Problem
Existing high-power DC circuit interruption technologies face challenges with residual energy dissipation and induced voltage/current peaks, leading to inefficiencies and potential damage, particularly in high-voltage direct current transmission systems like offshore wind farms and ship drives.
Innovation Solution
A high-performance switch with anti-series transistors and a switchable ohmic resistor is used to dissipate residual energy and dampen peaks, allowing for safe and efficient interruption of DC circuits by short-circuiting through the ohmic resistor, controlled by a unit that also manages transistor switching and voltage/current monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If mechanical switches are used to interrupt DC circuits, then the circuit can be disconnected, but the disconnection is slow and arcs require extensive design effort to extinguish
Solution Approach 1:
The patent replaces mechanical switches with semiconductor switches (IGBTs arranged anti-series) to eliminate mechanical moving parts and arc generation. The semiconductor switches provide contactless switching, achieving high-speed operation without the arc extinction problems inherent in mechanical switching systems.
2Speed
If semiconductor switches are used to interrupt high-power DC paths, then switching speed is high and no arcing occurs, but high levels of energy remain in the circuit leading to interruption problems
Solution Approach 1:
The patent extracts the energy dissipation function from the main switching path by introducing a separate energy dissipation path with a resistor. When the IGBTs open, the residual energy is redirected through this dedicated dissipation path, allowing the main switches to perform their interrupting function without being burdened by the energy that must be removed from the circuit.
Solution Approach 2:
The resistor acts as an intermediary element that mediates the energy transfer from the capacitive circuit elements to the ground. This intermediary provides a controlled path for energy dissipation, preventing voltage spikes and enabling safe interruption of the high-power DC path by the semiconductor switches.
3Reliability
If high-power DC circuits are interrupted, then current flow is stopped, but induced voltage and current peaks occur that can damage components
Solution Approach 1:
The patent implements beforehand cushioning by providing a dedicated energy dissipation path with a resistor that is ready to absorb induced voltage and current peaks when they occur during circuit interruption. This pre-configured protection path cushions the impact of transient overvoltages and protects the IGBTs and other components from damage.
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 enables quick and complete de-energization of current paths, preventing damage and ensuring operational reliability at high power levels, with compact design and low maintenance, suitable for high-power applications up to 30 kW.
Implementation Method 1
quickly dissipating the energy remaining in the current path via the ohmic resistor
Implementation Method 2
induced voltage and/or current peaks that occur during disconnection, which can occur due to the high voltages and currents even with low inductivities, are damped via the switchable ohmic resistance
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention relates to a high-power switch (1) for interrupting DC circuits, comprising two current paths (2a, 2b) for high power, wherein at least two transistors (3, 4) connected in an anti-series manner in one of the current paths are provided in such a way that each transistor can block or enable exactly one of the two possible flow directions and at least one control (5) is provided for controlling the transistors. The aim of providing a high-power switch for bidirectionally interrupting DC circuits, which enables an interruption of the circuit for current flow in both possible current directions and also reduces the risk of remaining residual energy in the circuits, is achieved in that a connectable (6') ohmic resistor (R), by means of which the circuit can be short-circuited, is provided between the anti-serial transistors of the current path.