Contactor Coil Control Using Dual Magnetic Units to Cut Heating
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Solution Overview
Problem
Conventional contactors face issues with high energy consumption and coil heating due to uncontrolled current flow, leading to limited control and reduced contact life, and existing solutions like flyback circuits are complex and costly.
Innovation Solution
A control device with a high side control unit and two low side control units, along with a freewheeling unit, manages current flow through two magnetic units to optimize inrush and hold phases, reducing power consumption and simplifying control logic.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a larger current is ensured to flow through the coil for reliable pull-in, then the contactor engagement is reliable, but energy consumption increases and coil heating occurs
Solution Approach 1:
The patent implements a two-phase control strategy where the coil is energized with high current only during the inrush phase for a limited time to ensure reliable contactor engagement, then transitions to a hold phase with reduced current. This periodic action pattern ensures reliable pull-in while minimizing energy consumption during the sustained operating period.
Solution Approach 2:
The patent dynamically switches between two control modes: an inrush control mode that provides high current for reliable engagement, and a hold control mode that maintains engagement with lower current. This dynamic adaptation of control parameters resolves the contradiction between ensuring reliable engagement and minimizing energy consumption.
2Device complexity
If one switch controls one coil with uncontrolled current, then the control circuit is simple, but the movable contacts strike frequently causing damage and short life
Solution Approach 1:
The patent segments the control function into two separate switches: a first switch controlling the inrush phase and a second switch controlling the hold phase. This segmentation allows independent optimization of each phase, reducing unnecessary switching operations during the hold phase and thereby extending contact life while maintaining acceptable control complexity.
3Use of energy by moving object
If a flyback circuit based coil control scheme is used, then coil current is controlled, but the solution becomes complex and costly
Solution Approach 1:
The patent extracts the energy recovery function from a complex flyback circuit and implements it using simpler components: two switches working in coordination with the coil's inherent inductance. The first switch handles inrush current while the second switch manages the hold phase, achieving energy control without requiring a flyback circuit.
4Use of energy by moving object
If a buck circuit is designed to hold the coil, then energy consumption is reduced, but the design difficulty is large and validation period is long
Solution Approach 1:
The patent replaces the complex, difficult-to-validate buck circuit with a simpler switch-based control approach using readily available semiconductor switches. This substitution achieves similar energy savings while dramatically reducing design complexity and validation requirements, making the solution more manufacturable.
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 power consumption, extends contactor life by minimizing switching frequency, and simplifies control logic while maintaining reliable contact operation.
Implementation Method 1
When the contactor coil is energized, the coil current may generate a magnetic field. The generated magnetic field causes the static magnetic core to generate electromagnetic suction to attract the movable magnetic core.
Data Source
AI summary
The present disclosure relates to contactor, and device and method for controlling same. A control device for a contactor comprises a high side control unit, a first low side control unit, a second low side control unit, a freewheeling unit, and a controller. The high side control unit is configured to switch on or switch off the connection of the first magnetic unit and the second magnetic unit of the contactor with a power supply. The first low side control unit is configured to switch on or switch off the connection of the first magnetic unit with the reference voltage node. The second low side control unit is configured to switch on or switch off the connection of the second magnetic unit with the reference voltage node. The freewheeling unit is connected across a branch comprising a first magnetic unit and a first low side control unit and connected across a branch comprising a second magnetic unit and a second low side control unit. The controller is configured to control the operation of the high side control unit, the first low side control unit, and the second low side control unit. Embodiments of the present disclosure may enable intelligent control of contactors with simple control logic.