Electrical Performance Design for Circuit Breakers Based on Multi-domain Sequential Coupling

This paper presents an electrical performance design method of mechatronic circuit breakers (CB) based on multi-domain sequential coupling (MSC). Firstly, the attraction force of electromagnetic trip mechanism is obtained by Maxwell formula and Ampere’s circuital law. The multi-body kinematics and dynamics model of CB are built by recursive Euler–Lagrange partial differential equations using generalized coordinates. The electrical performance optimization model of CB is built to obtain the optimal opening angle, clearance and over-travel of the contact. The MSC piecewisely combines one field with another field according to the variation and sensitivity of the unstable field to perform multiphysics simulation  such as magnetohydro-dynamics (MHD). The physical experiment of rated short-circuit capacity is carried out to verify the proposed method using infrared thermogram. The peak voltage, Joule integral and on–off time of the CB are optimized and shortened with maximum change of ratio 8.13% which proves that the CB has better reliability with longer mean time between failures.