Pre-charge Circuit Semiconductor Switch Relay In-rush Current
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Pre-charge circuits using solid state and/or electromechanical sub-relays in high voltage applications suffer from reliability issues due to fatigue and are expensive and large, limiting their use in space-constrained systems.
Innovation Solution
A pre-charge circuit for electromechanical relays that includes a semiconductor switch connected across the relay contacts in series with a resistor, powered by a driver, which pre-charges capacitors to limit in-rush current without mechanical switching components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If solid state and/or electromechanical sub-relays are used in pre-charge circuits, then in-rush current can be limited, but reliability deteriorates due to fatigue of moving switch parts
Solution Approach 1:
The patent replaces mechanical switching components (electromechanical sub-relays and solid state relays with moving parts) with a semiconductor switch that has no mechanical moving parts. This substitution eliminates fatigue of moving switch parts while maintaining the ability to limit in-rush current through the semiconductor switch's electrical control capabilities.
2Object-affected harmful factors
If solid state and/or electromechanical sub-relays are used in pre-charge circuits, then in-rush current can be limited, but device size increases
Solution Approach 1:
The semiconductor switch occupies significantly less space than traditional electromechanical sub-relays or solid state relays with moving parts. By eliminating the mechanical structure and associated components, the overall device size is reduced while maintaining the pre-charge functionality.
3Object-affected harmful factors
If solid state and/or electromechanical sub-relays are used in pre-charge circuits, then in-rush current can be limited, but manufacturing cost increases
Solution Approach 1:
The semiconductor switch eliminates the need for complex mechanical assemblies, moving parts, and associated housing structures required by electromechanical relays. This simplification reduces manufacturing complexity, assembly steps, and overall production costs while achieving the same in-rush current limiting function.
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 effectively prevents damage to relay contacts and capacitors by limiting in-rush current, enhancing reliability and reducing size and cost compared to traditional pre-charge modules.
Implementation Method 1
a resistor configured to be electrically connected in series with the semiconductor switch between the coil and the relay contacts of the electromechanical relay
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A pre-charge circuit (10) is provided for an electromechanical relay (12) having a coil (22) and relay contacts (26). The pre-charge circuit (10) includes a semiconductor switch (30) configured to be electrically connected across the relay contacts of the electromechanical relay. The pre-charge circuit includes a resistor (32) configured to be electrically connected in series with the semiconductor switch between the coil and the relay contacts of the electromechanical relay. The pre-charge circuit includes a driver (34) configured to be electrically connected between the coil of the electromechanical relay and the semiconductor switch such that the driver is configured to power operation of the semiconductor switch. The semiconductor switch is configured to pre-charge a capacitor (16) of a load (14) of the electromechanical relay with electrical current through the resistor for limiting in-rush electrical current supplied to the relay contacts of the electromechanical relay.