Input relay phase selection pull-in control method

By obtaining the zero-crossing point of the three-phase voltage, the pull-in delay of the soft-start relay and the main power relay of the charging module is inferred and controlled, thus solving the problem of surge current during relay startup and improving the durability of the relay and the reliability of the charging module.

CN121749442APending Publication Date: 2026-03-27SHENZHEN UU GREEN POWER CO LTD
View PDF 0 Cites 1 Cited by

Patent Information

Application Number
CN202512009438.7
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2025-12-29
Publication Date
2026-03-27

AI Technical Summary

Technical Problem

During startup, the input relay of the existing charging module has a random phase between the control signal and the AC power grid voltage, causing the relay contacts to close near the peak voltage of the AC power, generating a huge surge current, which severely burns the relay and shortens its mechanical and electrical life.

Method used

By obtaining the zero-crossing points of the three-phase voltages, the zero-crossing points of the pull-in voltage and the pre-charge current of the soft-start relay and the main power relay are inferred. Their pull-in delay is calculated, and the relays are controlled to pull in sequentially at specific and optimized phase moments to suppress inrush current.

Benefits of technology

It significantly improves the durability and stability of the relay and charging module, reduces losses, and enhances the reliability of the charging module.

✦ Generated by Eureka AI based on patent content.

Smart Images

  • Figure CN121749442A_ABST
    Figure CN121749442A_ABST
Patent Text Reader

Abstract

The invention relates to a relay phase selection pull-in control method. The method comprises the following steps: acquiring a first phase voltage zero crossing point, a second phase voltage zero crossing point and a third phase voltage zero crossing point; speculating pull-in voltage zero crossing points of the first soft start relay and the second soft start relay based on the third phase voltage zero crossing point, and speculating pull-in time delay of the first soft start relay and the second soft start relay based on the pull-in voltage zero crossing points; speculating a first pre-charging zero crossing point based on the first phase voltage zero crossing point, and speculating the pull-in time delay of the first main power relay based on the first pre-charging zero crossing point; and a second pre-charge zero crossing point is speculated based on the second phase voltage zero crossing point, and the pull-in time delay of the second main power relay is speculated based on the second pre-charge zero crossing point. Inrush current can be suppressed, loss is reduced, and the service life of the relay is prolonged.
Need to check novelty before this filing date? Find Prior Art

Citation Information

Cited By

  • Method and device for suppressing magnetizing inrush current of transformer and electronic equipment

    CN122118622A