Calculation and analyses of permanent magnetic actuator dynamic behavior

The study of dynamic behavior of permanent magnetic actuator (PMA) involves solution of an electrically, magnetically and mechanically coupled problem. Based on the establishment of mathematic model, this paper solves the electric circuit equation, electromagnetic equation and mechanic equation simultaneously to obtain the PMA dynamic behavior by adopting four-order Runge-Kutta method and finite element method. In the calculation, both the nonlinear material properties and the magnetic leakage are considered. By calculating dynamic behavior of vacuum circuit breakers equipped with bistable and monostable PMA respectively, a few curves such as current across the coil and movable contact velocity are obtained. And related experiments are also carried out. In the test, the open and closing speed of contacts are measured and the current curves in open and closing coil are also obtained. The comparison of theoretical and experimental results shows that the calculation results are correct and reliable.