DC Circuit Breaker Bypass Switch Actuation
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Solution Overview
Problem
Conventional DC protective switching devices require large and power-hungry power supplies to quickly open bypass switches during safety shutdowns, leading to increased size, power loss, and reduced service life due to constant recharging of capacitors, which is unnecessary for most operational conditions.
Innovation Solution
The DC protective switching device utilizes the smoothing capacitance present at the output of a rectifier as an energy source to drive the bypass switch, eliminating the need for a large power supply and allowing for rapid opening with a small number of turns in the bypass switch excitation coil, reducing inductance and opening time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a powerful power supply unit with large capacitors is used to quickly open the bypass switch, then the opening speed of the bypass switch is improved, but the device size and power loss increase significantly
Solution Approach 1:
The patent extracts the energy storage function from the internal power supply unit and relocates it to the rectifier's smoothing capacitor. This removes the need for large internal capacitors and powerful power supplies, significantly reducing device size while maintaining the ability to quickly open the bypass switch when needed.
Solution Approach 2:
The rectifier's smoothing capacitor serves dual purposes: it continues to perform its original function of smoothing rectified voltage, and simultaneously provides the energy storage needed to quickly actuate the bypass switch. This eliminates the need for separate dedicated energy storage components.
2Speed
If a powerful power supply unit is used to quickly open the bypass switch, then the opening speed is improved, but the power loss and cooling requirements increase
Solution Approach 1:
The power supply function for the bypass switch is extracted from the main power supply unit. The smoothing capacitor provides the necessary energy bursts without requiring the main power supply to be continuously powerful, reducing its size and associated power losses.
Solution Approach 2:
The power supply unit only needs to operate at high power during brief periods when the bypass switch needs to be opened quickly. Between these events, it operates at lower power levels, reducing average power loss and cooling requirements.
3Use of energy by moving object
If a bypass switch drive with high number of turns is used, then the required current is reduced, but the inductance increases and opening time is slowed down
Solution Approach 1:
The patent changes the voltage parameter instead of using high current. By providing high voltage from the smoothing capacitor, the system achieves the necessary energy delivery with fewer turns in the excitation coil, maintaining low inductance and fast response while still reducing current requirements.
4Loss of energy
If a choke is added to reduce current rise rate during short circuits, then the power loss is reduced, but the device size and ohmic losses increase
Solution Approach 1:
The patent removes the choke from the circuit by changing the energy delivery method. Instead of using a choke to limit current rise, the system uses the inherent capacitance of the smoothing capacitor to provide controlled energy discharge, eliminating the need for additional inductive components and their associated space and losses.
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 results in a compact, low-power DC protective switching device that can quickly switch off short circuits with reduced size, power loss, and extended service life of semiconductors, as the bypass switch can be opened faster and with less energy consumption.
Implementation Method 1
a mechanical bypass switch (8), having at least one bypass switch excitation coil (21)
Implementation Method 2
uses the smoothing capacitance present at the output of the rectifier or the at least one smoothing capacitor (18) as an energy source for driving the bypass switch (8)
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a direct current circuit breaker device (1) having a first current path (2) and a second current path (5), a mechanical bypass switch (8) being arranged in the first current path (2), the bypass switch (8) having at least one bypass switch exciter coil (21). A first semiconductor circuit assembly (11) of the direct current circuit breaker device (1) is connected in parallel with the bypass switch (8), an electronic control unit (13) of the direct current circuit breaker device (1) being designed to actuate the first semiconductor circuit assembly (11). The direct current circuit breaker device (1) has a second semiconductor circuit assembly (22) which is actuated by the control unit (13), and the second semiconductor circuit assembly (22) is connected to the bypass switch exciter coil (21) in terms of circuitry. The invention proposes that at least one terminal of the second semiconductor circuit assembly (22) is connected directly to the second supply terminal (6) in terms of circuitry.