Electromechanical Relay Control Using Optical Contact Detection
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Solution Overview
Problem
Electromechanical relays experience wear and reduced lifespan due to electric arcs during state changes, and existing control methods are costly and require specific components, limiting their efficiency and longevity.
Innovation Solution
A control device and method that detects the position of the electromechanical relay's contact using a conductive surface to generate a detection signal, determining the switching time to ensure the contact changes state when the alternating signal is zero, thereby avoiding electric arcs and extending the relay's lifespan without the need for expensive components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electromechanical relay is controlled to open or close without considering switching time, then the control is simple, but electric arcs occur at the contact causing wear and reduced lifespan
Solution Approach 1:
The patent uses an optical sensor to detect the actual position of the relay contact and feeds this information back to the control unit. The control unit compares the detected position with the commanded position and adjusts the control signal timing based on the measured switching time, creating a closed-loop feedback system that eliminates electric arcs while maintaining reliable operation.
Solution Approach 2:
The patent measures the switching time of the relay contact in advance and stores this information for use during normal operation. By knowing the switching time beforehand, the control unit can predict when the contact will actually change state and issue control signals at the appropriate time to ensure switching occurs at zero voltage, preventing electric arcs.
2Reliability
If an optical sensor is used to detect contact position and measure switching time, then the relay lifespan is extended by avoiding electric arcs, but the system becomes expensive
Solution Approach 1:
The patent replaces expensive specialized components with a combination of a simple optical sensor (such as a phototransistor or LED) and a microcontroller. This substitution uses readily available, low-cost electronic components to achieve the same function of detecting contact position and measuring switching time, significantly reducing manufacturing costs while maintaining the ability to extend relay lifespan.
Solution Approach 2:
The system uses the relay's own switching characteristics to generate the control signals needed for optimal operation. By measuring the actual switching time and using this information to timing the control signals, the system essentially controls itself without requiring external expensive components or complex external control circuits.
3Reliability
If a triac is arranged in parallel with the electromechanical relay to control switching, then the relay lifespan is extended, but the supply power of the load is limited and space is consumed
Solution Approach 1:
The patent extracts the power control function from the triac-based system and transfers it to the electromechanical relay itself. By using the optical sensor to detect contact position and the microcontroller to timing control signals based on measured switching time, the system eliminates the need for a parallel triac, freeing up load power capability and reducing space requirements on the electronic card.
Solution Approach 2:
The electromechanical relay is made multi-functional by using it both as the power switching device and as the subject of control optimization. The same relay that switches the load power is also the device whose switching characteristics are measured and used to generate control signals, eliminating the need for separate triac components and their associated limitations.
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 effectively extends the lifespan of electromechanical relays by ensuring state changes occur when the alternating signal is zero, reducing wear and eliminating electric arcs, while using generic components to lower costs and improve reliability.
Implementation Method 1
detection means comprising a conductive surface, and are configured to generate the detection signal on the conductive surface when the contact passes from the open position to the closed position or vice versa
Data Source
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Figure 5a~5b
AI summary
A control device for an electromechanical relay (1), the electromechanical relay (1) being disposed between a load (3) and an alternating signal (VA) and having a movable contact (20) between an open and a closed position, comprises control means for the electromechanical relay (2) configured to control the opening or closing of the electromechanical relay taking into account a switching time, such that the contact (20) is in the open or closed position when the alternating signal (VA) is substantially equal to zero, the control device (1') being characterized in that it comprises: - means for detecting the open or closed position of the contact (20); and - means for determining said switching time. Particularly suitable for use in household appliances.