Self-Learning Relay Turn-Off Control System
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Solution Overview
Problem
Existing relay turn-off systems face challenges in reliably turning off relays during zero-cross times of AC currents, leading to arcing and reduced relay lifespan, with existing solutions requiring complex algorithms, custom optical sensors, or random timing adjustments that do not effectively eliminate arcing.
Innovation Solution
A self-learning relay turn-off control system that uses a microprocessor to measure and adjust turn-off signal timing based on empirically determined duration times and modulo operations to ensure the relay opens during zero-cross periods, eliminating the need for custom components and reducing arcing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the relay turn-off timing is adjusted to open during zero-cross point, then the arcing is reduced and relay lifespan is extended, but a complicated algorithm is required to detect the true turn-off time due to signal bounce conditions
Solution Approach 1:
The system performs preliminary measurement of the relay turn-off duration time during initial operation phases. This pre-characterization of the relay's actual turn-off behavior is stored and subsequently used to calculate accurate zero-cross turn-off times, eliminating the need for complex real-time signal bounce analysis algorithms.
Solution Approach 2:
The system uses the measured turn-off duration time as feedback to continuously refine and adjust the turn-off signal timing. By incorporating this measured parameter into the timing calculation algorithm, the system achieves accurate zero-cross switching without requiring complex signal bounce detection and correction algorithms.
2Reliability
If an optical sensor is used to detect arcing and adjust turn-off timing, then arcing is minimized, but the cost increases due to custom components
Solution Approach 1:
The invention replaces optical sensing mechanisms with an electrical measurement approach. Instead of using optical sensors to detect arcing, the system measures the electrical turn-off duration time directly from the control signal and uses this electrical parameter to optimize turn-off timing, thereby eliminating costly custom optical components.
Solution Approach 2:
The system uses its own control signal and inherent timing capabilities to measure and determine the optimal turn-off duration. This self-measurement approach eliminates the need for external sensing components, reducing system cost while maintaining effective arc protection.
Data Source
AI summary
An exemplary embodiment is disclosed of a relay turn-off control system for use with an alternating-current (AC) signal input. The system may include a relay, a relay current load sensor connected to the relay, and a rectifier circuit connected to the relay current load sensor and having an output. A microprocessor may be connected to the rectifier circuit output. The microprocessor may be configured to set a relay turn-off signal output time based on an empirically determined duration time for the relay to turn-off and further based on determining a zero-cross period via use of a modulo operation.