Contactor Control Unit for Energy-Efficient Closing
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Solution Overview
Problem
Electromagnetically operated contactors in electrical networks waste energy due to high current usage during the closing process, leading to increased temperature and reduced operational time, as well as higher costs and energy inefficiency.
Innovation Solution
A control unit method that estimates model parameters based on coil current and voltage measurements to predict the behavior of the contactor, allowing for reduced pull-in energy consumption by detecting the exact time of contact closure and switching to a lower hold current, thereby minimizing energy waste and prolonging operational time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high current is applied to the coil for a fixed period of time including a safety margin to secure reliable contact making, then the contactor closing reliability is improved, but energy consumption increases and coil temperature rises
Solution Approach 1:
The control unit continuously monitors the actual coil current and compares it with the expected current from a model prediction. When the difference between measured and predicted current exceeds a threshold, the system detects that closing has occurred and immediately reduces the current to hold level, eliminating the need for a fixed safety margin period.
Solution Approach 2:
The system transitions from a static fixed-time control approach to a dynamic adaptive control approach. The coil current is adjusted in real-time based on actual closing detection, allowing the system to optimize the current profile dynamically rather than using a predetermined fixed duration.
2Reliability
If high current is applied to the coil for a fixed period of time including a safety margin to secure reliable contact making, then the contactor closing reliability is improved, but coil temperature increases adversely affecting functionality
Solution Approach 1:
By implementing feedback-based closing detection through current monitoring and model comparison, the system can immediately detect when closing has occurred and reduce the current accordingly, preventing excessive temperature rise while maintaining reliable closing.
Solution Approach 2:
The system uses a model to predict the expected current behavior before closing occurs. By comparing actual current with predicted current in advance, the system can detect closing at the optimal moment and avoid unnecessary high current application that would increase temperature.
3Reliability
If high current is applied after the contactor has closed to provide a safety margin, then contact making reliability is improved, but unnecessary energy is wasted
Solution Approach 1:
The system eliminates the fixed safety margin period by using feedback-based detection. The control unit monitors the current and immediately detects when closing has occurred, switching to hold current at the precise moment of closing rather than waiting for a predetermined time period to elapse.
Solution Approach 2:
The system uses its own operational characteristics (the change in coil current) to detect closing automatically. By monitoring its own current consumption and comparing it with predicted values, the contactor system can self-detect the closing state and adjust its power consumption accordingly without external intervention.
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
This approach reduces energy consumption, lowers operational costs, and extends the lifespan of electronics by minimizing energy waste and allowing for higher operating frequencies.
Implementation Method 1
Operation of such contactor entails applying a current to the coil, whereby a magnetic flux is produced in the electromagnet.
Implementation Method 2
The magnetic flux attracts the armature, which forces contacts of the contactor to close.
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The present teachings relate to a method 60 in a control unit 12 for closing a contactor device 1. The control unit 12 is configured to enable the movement between the closed position and the open position by energizing a coil 6 of an electromagnetic circuit. The method 60 comprises applying 61 a voltage over the coil 6; determining 62, during a first period of time, current through the coil 6 and voltage over the coil 6 and estimating based thereon model parameters for a model predicting the behavior of the current through the coil 6 if the contactor device 1 were to stay in an open position, and measuring 63, after the ending of the first period of time, current through the coil 6 and determining 64 a difference between, on the one hand the measured current and, on the other hand a predicted current of the model, and repeating the measuring 63 and determining 64 until a state change from open position to closed position is detected by the difference in current.