Virtual prototyping and parameter optimization of differential electromagnetic relays with double permanent magnets

The differential electromagnetic relay with double permanent magnets has advantages of low voltage, high sensitivity and fast action. However, slow breaking velocity and closed bounce result in its short life. Based on the differential electromagnetic system with double permanent magnets and the mathematical model of the relay's dynamic characteristics, a finite element method (FEM) static simulation model of the electromagnetic system and the multi-body dynamics model of the contact spring system were built. Finally, the virtual prototyping model of the relay was built to realize dynamic characteristics simulations. The test data validate the simulation results. Then, the influence of key parameters on the force characteristics was studied using the static simulation model and the optimized values of the key parameters were achieved by entropy weight, grey relational analysis and orthogonal experiment. Through dynamic characteristics simulation, the breaking velocities of N.C. contacts and N.O. contacts are increased by 53.20% and 5.76% respectively, and simultaneously the making velocity of N.C. contacts is decreased by 2.56% compared with the velocities before optimization. Finally, the goals of lightening arc erosion during contacts breaking and contacts closing bounce and improving the life of relays are reached by verifying the validity of this parameter optimization method.