Capacitor-Based High-Voltage Contactor for Low-Heat Hold-In
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Solution Overview
Problem
Solenoid-based contactors in high voltage bus systems, such as those in electric vehicles, generate excessive heat due to the current required to maintain switch closure, which can be detrimental to temperature-sensitive equipment.
Innovation Solution
A capacitor-based contactor design featuring first and second capacitor elements with a dielectric element that moves under a bias force, allowing a controllable voltage to switch the contactor on without continuous current draw, utilizing a conductive element with flexible elements and a bias spring to establish and break contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solenoid-based contactor is used to switch high voltage, then the contactor can maintain switch closure, but excessive heat is generated due to continuous current draw
Solution Approach 1:
The patent replaces the electromagnetic solenoid system with a capacitor-based electrostatic system. Instead of using continuous current through a solenoid coil to maintain contact closure, the invention uses charged capacitor elements that create electrostatic forces to hold the dielectric element in position, thereby maintaining contact closure without continuous current draw and reducing heat generation
Solution Approach 2:
The patent employs periodic charging of the capacitor elements rather than continuous current flow. The capacitors are charged to store energy, and this stored energy is used to maintain the contactor in the closed state. This periodic energy input followed by energy storage and utilization eliminates the need for continuous current, thereby solving the heat generation problem while maintaining reliable switch closure
2Productivity
If a solenoid-based contactor is used to switch high voltage, then the contactor can connect and disconnect power, but high current is required to maintain activation
Solution Approach 1:
The patent replaces the electromagnetic solenoid system with a capacitor-based electrostatic system. Instead of using continuous current through a solenoid coil to maintain contact closure, the invention uses charged capacitor elements that create electrostatic forces to hold the dielectric element in position, thereby maintaining contact closure without continuous current draw and reducing heat generation
Solution Approach 2:
The patent changes the fundamental operating parameter from continuous electrical current (in solenoids) to stored electrical energy in capacitors. By transitioning from a current-driven electromagnetic system to an energy-stored electrostatic system, the contactor maintains switching capability while dramatically reducing ongoing current requirements to only what is needed for periodic capacitor recharging
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 capacitor-based contactor maintains the on-state without additional current, significantly reducing operating temperature compared to solenoid-based contactors, thus mitigating heat-related issues in high voltage systems.
Implementation Method 1
A controllable voltage source is operative to place an activating voltage across the first and second capacitor elements thereby causing the dielectric element to move in the gap
Implementation Method 2
A bias element is coupled to the dielectric element and urges the dielectric element toward a first position
Data Source
AI summary
An electrical contactor for use in a high voltage bus utilizes two capacitor plates and a dielectric element movable in a gap between the plates under a charging voltage applied to the plates. The dielectric element is biased to a contactor off, or open, position by a biasing element, such as a spring. Once activated, the contactor remains closed under the influence of the charging voltage across the capacitor plates, yet does not draw a current during this state. The contactor may be released by a controllable discharge circuit placed across the capacitor plates.