Power supply circuit of contactor coil

Abstract

The invention discloses a power supply circuit of a contactor coil. The power supply circuit of the contactor coil comprises a direct-current to direct-current conversion unit, an alternating-current to direct-current conversion unit, a selection unit, an energy storage unit, a first switch and the contactor coil, wherein when the first switch is turned on and first direct-current voltage is larger than second direct-current voltage, the selection unit selects the first direct-current voltage and the energy storage unit to jointly supply power to the contactor coil; when the first switch is turned on and the first direct-current voltage is smaller than the second direct-current voltage, the selection unit selects the second direct-current voltage and the energy storage unit to jointly supply power to the contactor coil; and when the first switch is turned on and the first direct-current voltage is equal to the second direct-current voltage, the selection unit selects the first direct-current voltage, the second direct-current voltage and the energy storage unit to jointly supply power to the contactor coil. The power supply circuit provided by the invention has the advantage that the reliability of power supply to the contactor coil is high.

Description

technical field [0001] The present application relates to the field of circuits, in particular to a power supply circuit of a contactor wire package. Background technique [0002] The contactor is a breaking and closing device that can frequently close, carry and break the normal current and the specified overload current, and is one of the important components in the automatic control system. Contactors are often used to control the start and stop of motors, fans, water pumps and other equipment. When the contactor is opened and closed, it is generally realized by controlling the power supply circuit of the contactor wire pack in the contactor to energize and de-energize the contactor wire pack. When the wire package of the contactor is energized, a strong magnetic field will be generated, which will cause the pull-in magnet in the contactor to move and drive the contactor to close. When the wire pack of the contactor is powered off, the pull-in magnet will separate and dr...

AI Technical Summary

Problems solved by technology

[0004] The inventor found that in the prior art, when the DC voltage converted from the grid voltage is used to supply power to the contactor package, if there is a problem with the grid voltage, such as a large fluctuation range of the grid voltage, or a low voltage ride through (LVRT, Low Voltage Ride Through) In the event of an accident, the power supply circuit may not be able to supply power to the contactor wire package normally, or even a power failure occurs, so the reliability of the power supply for the contactor wire package is poor

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