Relay Welding Detection Using Universal Voltage Sensor
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Solution Overview
Problem
Conventional methods for determining welding in relays require multiple current or voltage sensors, increasing manufacturing costs due to the need for sensors proportional to the number of relays used in distributed power supply systems.
Innovation Solution
A controller that performs a series of welding checks across multiple relays using fewer sensors by strategically turning on and off relays and utilizing potential difference measurements to determine welding occurrences, allowing for efficient detection with reduced sensor requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple current sensors or voltage sensors are provided to determine welding in each relay, then welding detection accuracy is improved, but manufacturing cost increases
Solution Approach 1:
A single voltage sensor is made universal by measuring potential differences across multiple relay combinations through strategic switching. The sensor detects welding in relays R1-R6 by measuring voltage across different terminal pairs (e.g., T1-T2 for R1, T3-T4 for R2, etc.), allowing one sensor to perform the function of multiple sensors would have been needed in conventional approaches.
Solution Approach 2:
Switching relays are introduced as intermediary components that enable a single voltage sensor to access multiple measurement points. The switching relays act as mediators that connect the sensor to different relay terminals in sequence, allowing indirect measurement of welding conditions without requiring direct sensor placement at each relay location.
2Reliability
If welding checks are performed without proper sequencing, then detection completeness is improved, but risk of short circuit increases
Solution Approach 1:
The switching relays are turned off in advance before each voltage measurement is taken. This preliminary action ensures that only the target relay is energized during measurement, preventing simultaneous energization of multiple relays that could create short circuits. For example, before measuring voltage across T1-T2 to check relay R1, all other switching relays are ensured to be off.
Solution Approach 2:
Welding detection is performed periodically for each relay through sequential switching and measurement cycles. Each relay is checked in isolation through periodic activation of its corresponding switching relay, ensuring complete detection coverage while maintaining safety through time-separated measurements that prevent short circuit 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
Enables determination of welding in multiple relays using fewer sensors than conventional methods, reducing manufacturing costs and preventing unnecessary checks that could cause short circuits.
Implementation Method 1
Occurrence of welding in a relay can be determined based on a change in a potential difference between contact terminals at the time of turning on and off the relay
Implementation Method 2
the occurrence of welding in a relay can be determined based on a current value at a current sensor in the path of current flowing through the relay when the relay is turned off
Data Source
AI summary
A controller 10 performs a first welding check and a second welding check in any order, and then performs a third welding check before a fourth welding check and also performs a fifth welding check before a sixth welding check. The first welding check is performed by turning on a first relay 18. The second welding check is performed by turning on a second relay 19. The third welding check is performed by turning on an in-phase relay, a third relay 20, and a fourth relay 21. The fourth welding check is performed by turning on an out-of-phase relay, the third relay 20, and the fourth relay 21. The fifth welding check is performed by turning on the in-phase relay, a fifth relay 22, and a sixth relay 23. The sixth welding check is performed by turning on the out-of-phase relay, the fifth relay 22, and the sixth relay 23.