Contactor Position Feedback to Prevent High-Voltage Levitation
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Solution Overview
Problem
Existing electromagnetic switching devices for power electrical circuits are not suitable for high voltages above 300 V, as they experience unwanted opening due to levitation phenomena caused by short-circuit currents, leading to electrical arcs and degradation.
Innovation Solution
A switching device with a detection system to determine the position of the main contactor's paddle, generating signals to maintain the contactor in the closed state by increasing the actuator's force when levitation is detected, using sensors to measure voltage or distance, and a control power supply to adjust the control signal levels accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the main contactor is used in high voltage power electrical circuits (above 300 V), then the device can handle higher voltage and power applications, but levitation phenomena occur due to short-circuit currents causing unwanted opening of the contactor
Solution Approach 1:
The patent implements a detection system that continuously monitors the position of the main contactor's paddle and provides feedback to the control power supply. When levitation is detected (paddle moves away from terminal), the system generates a second signal that triggers the control power supply to increase the control signal level from the second level to the third level, thereby counteracting the levitation phenomenon and maintaining reliable contactor closure during high voltage operation.
Solution Approach 2:
The control power supply dynamically adjusts the control signal parameter (voltage or current level) based on the detected contactor position. The control signal has three distinct levels: first level for closing, second level for normal holding, and third level (higher than second) for counteracting levitation. This parameter change allows the contactor to operate reliably in high voltage circuits by adapting the holding force to combat electromagnetic repulsion during fault conditions.
2Reliability
If the control signal level is increased to counteract levitation phenomena, then the contactor remains closed during short-circuit conditions, but the energy consumption of the actuator increases
Solution Approach 1:
The control signal is applied in distinct phases: a first level for a given initial duration to close the contactor, then reduced to a second level for normal operation, and temporarily increased to a third level only when levitation is detected. This periodic and conditional application of energy minimizes overall consumption while maintaining reliability during critical moments.
Solution Approach 2:
The control power supply adjusts the control signal parameter dynamically based on operational needs and detection system feedback. By using a lower second level during normal operation and only increasing to the third level when necessary (upon detecting paddle displacement), the system optimizes energy consumption while ensuring reliable contactor maintenance during both normal and fault conditions.
3Reliability
If a detection system is added to monitor contactor position and prevent levitation, then the reliability of the switching device improves, but the device complexity increases
Solution Approach 1:
The control power supply performs multiple functions: it generates the control signal for the actuator, receives signals from the detection system, determines when levitation occurs, and adjusts the control signal level accordingly. By making the control power supply multi-functional, the patent avoids adding a separate dedicated control unit, thereby reducing overall device complexity while maintaining improved reliability through levitation detection and prevention.
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
Prevents levitation phenomena, maintains the contactor in the closed state during short-circuit conditions, optimizing device size and reliability by reducing electronic components and enhancing protection against short-circuit currents.
Implementation Method 1
a coil 18 configured to cause the main contactor 12 to close and to hold it in the closed state when the coil 18 is energized
Implementation Method 2
a spring 20 configured to cause the main contactor 12 to open and to hold it in the open state when the coil 18 is no longer energized
Implementation Method 3
the detection system includes at least one voltage sensor configured to measure a voltage between the contact and at least one of the first and second terminals
Data Source
Figure 1~2
Figure 3~8
AI summary
The invention relates to a switching device (30) comprising at least one main contactor (34), a control power supply (44) and an actuator (40) configured to cause a change from an open state to a closed state of the main contactor (34) upon encountering a force generated by a spring (42), said contactor (34) having a paddle (34.1) and at least one terminal (34.2), the paddle (34.1) being configured to occupy a position in contact with said terminal (34.2) and a position away from said terminal (34.2); characterized in that the switching device (30) comprises a detection system (48) configured to determine the position in contact or away from the paddle (34.1) of the main contactor (34), generate at least a second signal (50) as a function of the determined position of the paddle (34.1).1) of the main contactor (34) and transmit said second signal (50) to the control supply (44) and in that the control supply (44) is configured to generate a control signal intended to keep the main contactor (34) in the closed state upon receipt of the second signal (50).