Cosimulation of Bistable Permanent Magnet Circuit Breakers

Abstract

The breaking and closing coils of bi-stable permanent magnet circuit breaker (PMCB) shares magnetic circuit, which leads to the fast time-varying nonlinear coupling relationship between the permanent magnetic field and the electromagnetic field, and between the breaking and closing magnetic circuits, which brings difficulty to its simulation. Aiming at the difficulty, this paper designs a new co-simulation method: First, the equivalent magnetic circuit of the bi-stable permanent magnet actuator (PMA) is established, and the ternary correspondence relationship of its electromechanical parameters is proved analytically for the first time. Then, the “equivalent electric circuit” of magnetic circuit in dynamic process of bi-stable PMA is proposed for the first time by analogy with the transformer model, and the calculation method of the time-varying parameters in this model is given. Finally, the “equivalent electric circuit” of magnetic circuit is used as a link, so the hardware circuit, software strategy and PMCB are connected together to form a point-by-point closed-loop co-simulation method. This simulation method can reflect the dynamic interaction between the electromagnetic field and the permanent magnetic field of the breaking and closing magnetic circuits, and also can reflect the dynamic interaction between the control module and the PMCB. So this method lays the foundation for simulation design of the high-performance bi-stable PMCB.