Relay Load Balancing Control for AC Switch Service Life
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Solution Overview
Problem
Current AC sensing controllers fail prematurely due to the limited rated switching life of relays, which restricts their use in applications like garages.
Innovation Solution
A sensing control device with a load balancing function that includes an input terminal, output terminal, switches, processing module, and sensing module, which estimates the aging value of each switch and selects the one with the lowest aging value for activation, using coefficients to accurately reflect the switch's condition and includes a current detection module for fault detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a relay is used as a switch in an AC sensing controller, then the device can be manufactured with simple structure and low cost, but the service life is limited to around 100,000 switching operations
Solution Approach 1:
The patent divides the switching function into multiple relays (first relay and second relay) that share the switching load. By segmenting the switching operations between multiple relays, the wear on each individual relay is reduced, extending the overall service life while maintaining the simplicity of using relay-based switching
2Duration of action of stationary object
If multiple switches are used to extend service life through load sharing, then the service life is extended, but the device complexity increases due to need for aging estimation and switch selection
Solution Approach 1:
The patent implements preliminary action by continuously monitoring and estimating the aging degree of each relay before switching operations occur. The microcontroller unit maintains aging degree information and uses it to proactively select which relay to use next, preventing overload before it occurs. This preliminary monitoring and selection mechanism simplifies the control logic compared to reactive approaches
3Ease of operation
If the relay is selected without considering aging, then the control logic is simple, but the relay may fail prematurely due to accumulated wear
Solution Approach 1:
The patent implements feedback by continuously monitoring the aging degree of relays and using this information to dynamically select which relay to activate. The microcontroller unit receives feedback from the aging estimation (based on switching counts and operating conditions) and adjusts relay selection accordingly, always choosing the relay with the lowest aging degree. This feedback loop maintains simple control logic while significantly improving reliability
Data Source
AI summary
A sensing control device includes an input terminal, an output terminal, a plurality of switches, a processing module and a sensing module. The input terminal is connected to a power source. The output terminal is connected to a controlled device. The switches are connected to the input terminal and the output terminal. The processing module is connected to the switches. The sensing module is connected to the processing module. The processing module executes an aging estimation process to estimate the aging value of each of the switches upon receiving a sensing signal from the sensing module. The processing module selects one of the switches based on the aging values of the switches, and turns on the selected switch to activate the controlled device.