Contactor Coil Control With Freewheel Current for Lower Heat
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Solution Overview
Problem
Conventional contactor coil control solutions, such as flyback and low-side coil control, result in high power consumption and short service life due to rapid temperature rise, and are difficult to design with effective diagnostic functions.
Innovation Solution
A control device comprising high-side and low-side control units, a freewheel unit, and a controller that manages the operation of these components to optimize energy transfer and consumption during inrush and holding phases, reducing power usage and enhancing performance by using a freewheel diode and voltage stabilization protection units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional flyback circuit-based coil control solution or low side coil control solution is employed, then the contactor can be controlled to close contacts and achieve load control, but the power consumption is large causing rapid temperature rise which shortens service life
Solution Approach 1:
The patent implements periodic switching control where the first high-side control unit and first low-side control unit are switched on during an inrush phase, then switched off during a freewheel phase, and subsequently switched on again during a holding phase. This periodic action allows the magnetic unit to be energized only when necessary, reducing continuous power consumption and heat generation while maintaining contactor reliability
Solution Approach 2:
The patent extracts the freewheeling function by introducing a dedicated freewheel unit that provides a separate current path for the magnetic unit. By taking out the freewheeling function from the main power supply path, the system allows current to circulate through the freewheel unit during the freewheel phase without drawing power from the main supply, thereby reducing power consumption while maintaining magnetic field integrity
2Ease of manufacture
If conventional flyback circuit-based coil control solution or low side coil control solution is employed, then the contactor can be controlled, but the design is difficult and verification cycle is long making diagnostic function difficult to achieve
Solution Approach 1:
The control device is segmented into distinct functional units: first high-side control unit, first low-side control unit, freewheel unit, second high-side control unit, and second low-side control unit. Each unit has a specific function and can be independently controlled by the controller. This segmentation simplifies the design process by breaking down the complex control circuit into manageable modules, each with defined responsibilities, making verification and diagnostic function implementation more straightforward
Solution Approach 2:
The controller acts as an intermediary that coordinates the operation of all control units. By centralizing the control logic in the controller, the patent simplifies the overall system design and verification process. The controller manages the switching sequences, monitors operational states, and can implement diagnostic functions, thereby reducing the complexity burden on individual control units and facilitating easier manufacturing and testing
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 reduces energy consumption and optimizes the working performance of the contactor, prolonging its service life and lowering operational costs while enabling more efficient diagnostic capabilities.
Implementation Method 1
by allowing an electrical current to flow through a coil to generate a magnetic field
Implementation Method 2
a current of the at least one magnetic unit flows through the freewheel unit
Data Source
AI summary
Embodiments of the present disclosure relate to a control device and method for a contactor. The control device comprises a first high-side control unit, a second high-side control unit, a first low-side control unit and a second low-side control unit. The first high-side control unit and the second high-side control unit respectively connect a first magnetic unit and a second magnetic unit of the contactor to a power supply. The first low-side control unit is connected between the first magnetic unit and a reference voltage node, and the second low-side control unit is connected between the second magnetic unit and the reference voltage node. The control device further comprises a freewheel unit connected to the first magnetic unit and the second magnetic unit. The control device further comprises a controller. The controller is used to control operations of the control units so that in a state that at least one magnetic unit of the first magnetic unit and the second magnetic unit is disconnected from the power supply, a current of the at least one magnetic unit flows through the freewheel unit. According to embodiments of the present disclosure, the contactor may be made more energy-saving, and the operation cost may be reduced.