Variable Resistance System for DC High-Voltage Switching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High voltage DC electrical circuits face significant challenges in managing inrush current peaks during re-engagement, which can exceed twice the maximum nominal current, potentially damaging components and blocking active components like IGBTs, and existing solutions for alternating currents are not directly transposable due to excessively long recovery times.
Innovation Solution
A controlled variable resistance system is introduced, capable of taking multiple resistance values, including an upper, intermediate, and lower value, to limit peak currents and facilitate faster capacitive charging, comprising discrete insertion resistors and switches controlled by an electronic unit to manage resistance values dynamically during the re-engagement process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an insertion resistor is used to limit inrush current, then peak current is reduced, but current recovery time becomes excessively long
Solution Approach 1:
The patent applies the dynamics principle by making the resistance value variable rather than fixed. The controlled variable resistance system dynamically adjusts its resistance value based on the charging state of the cable capacity, starting with high resistance to limit inrush current and then reducing resistance to enable rapid current recovery. This resolves the contradiction by allowing the system to have both current limiting and fast recovery capabilities through time-dependent resistance adjustment.
Solution Approach 2:
The patent applies parameter changes by varying the resistance parameter of the insertion resistor during the switching process. The resistance value is changed from a first value (limiting current) to a second value (enabling fast recovery) based on the charging progress of the cable capacity. This dynamic parameter adjustment allows the system to optimize both current protection and recovery speed, resolving the technical contradiction between limiting inrush current and maintaining fast current recovery.
2Device complexity
If a fixed resistance system is used, then current limiting is simple, but the system cannot adapt to different charging stages
Solution Approach 1:
The patent makes the resistance system dynamic by introducing a control device that adjusts the resistance value based on the charging stage of the cable capacity. The resistance transitions from a first value during initial charging to a second value during subsequent stages, allowing the system to adapt to different charging requirements. This dynamic approach balances the complexity of the control system with the need for adaptability across different operating conditions.
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 system effectively limits peak inrush currents to not exceed twice the maximum nominal value, preventing component damage and ensuring rapid re-establishment of nominal current, thereby supporting safe and efficient operation of high voltage DC electrical installations.
Implementation Method 1
A controlled variable resistance system is introduced, capable of taking multiple resistance values, including an upper, intermediate, and lower value, to limit peak currents
Data Source
Figure 1
Figure 2A~2D
Figure 3~6
AI summary
The invention relates to a DC high-voltage electrical installation comprising a switching device (22) for switching an electric current in the main circuit (24), and a method for controlling the closure of a switching device in such an installation, characterized in that the installation (23) includes a controlled variable resistor system (26) making it possible to modify the resistance value of the resistor system (26) seen by the current flowing through the main electrical circuit (24), said resistance value taking at least three distinct values: high, a lower value, and at least one nonzero intermediate value comprised between the high value and the low value. The installation includes a coordination device (32) making it possible to control switching times (T1, T2) of the resistance values of the resistor system (26).