Multi-Phase Relay Firing Angle Control for Low-Arcing Switching
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Solution Overview
Problem
Switching devices in industrial and commercial settings face challenges in consistently and efficiently connecting and disconnecting electric power due to non-instantaneous switching, leading to electric arcing and current oscillations, which can cause torque oscillations and reduce the lifespan of contacts.
Innovation Solution
A control system that includes a processor to determine harmonics data and generate a switching profile to control the movement of armatures in relay devices, using a higher voltage source than the rated voltage and a constant current source to minimize inductance variability and ensure consistent switching operations, and employing techniques like point-on-wave switching to reduce arcing and contact bounce.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional switching devices are used to connect and disconnect electric power, then the basic switching function is achieved, but electric arcing and current oscillations occur causing torque oscillations and reduced contact lifespan
Solution Approach 1:
The control system determines harmonics data and generates a switching profile before the actual switching operation. This preliminary analysis of the electrical waveform allows the system to predict the optimal switching moment and prepare the armature movement in advance, ensuring switching occurs at the precise point on the waveform that minimizes arcing and current oscillations.
Solution Approach 2:
The system continuously monitors electrical parameters and uses harmonics data to adjust the switching profile. By analyzing the feedback from the electrical system's harmonic content, the control algorithm optimizes the firing angle and armature movement timing to achieve consistent point-on-wave switching that eliminates harmful arcing effects.
2Reliability
If point-on-wave switching is implemented to reduce arcing, then contact wear is reduced, but precise timing control is required which increases device complexity
Solution Approach 1:
The patent replaces complex mechanical timing mechanisms with an electronic control system that uses processor-based harmonics analysis. Instead of mechanical clocks or timers, the system electronically determines the optimal switching point by analyzing electrical waveform harmonics, thereby achieving precise timing through computational methods rather than mechanical means.
Solution Approach 2:
The control system uses the electrical system's own harmonics data to automatically generate and adjust its switching profile. The system serves itself by utilizing the inherent electrical characteristics of the load and power source to determine the optimal switching moment, eliminating the need for external complex timing synchronization systems.
3Manufacturing precision
If a higher voltage source is used to drive the relay coil to ensure consistent armature movement, then switching time consistency is improved, but inductance variability causes firing angle deviations
Solution Approach 1:
The system dynamically adjusts the firing angle parameter based on real-time harmonics data analysis. By changing the firing angle to compensate for inductance variability, the control system ensures that the armature moves consistently despite variations in coil inductance. This parameter adjustment is calculated to maintain the desired point-on-wave switching timing.
Solution Approach 2:
The switching profile is made dynamic rather than static. The control system continuously adapts the armature movement timing and relay coil voltage based on the analyzed harmonics data, which reflects real-time changes in system inductance. This dynamic adjustment ensures consistent switching performance despite varying electrical 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 solution enables more consistent and efficient POW switching operations, reducing arcing and contact wear, and improving the reliability and lifespan of switching devices by ensuring precise timing and reduced variability in switching times.
Implementation Method 1
a relay coil to receive a driving voltage and generate a magnetic field to move the armature
Implementation Method 2
the switching devices may be opened and/or closed at specific points on the electric power waveform. Such carefully timed switching is sometimes referred to as 'point on wave' or 'POW' switching
Data Source
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AI summary
A control system may include a processor that may receive a first dataset associated with a current received at a load device coupled to a relay device. The processor may also determine harmonics data associated with the current and determine a switching profile to control moving a first armature of three armatures in the relay device based on the harmonics data. The switching profile is configured to control movement of the first armature between a first position and a second position, and wherein the switching profile comprises a firing angle for moving the first armature with respect to an electrical waveform, a second armature, and a third armature. The processor may then control a current provided to a relay coil of the relay device based on the switching profile, such that the relay coil causes the first armature to move.