Research On Optimization Of Direct-acting Double-breakpoint MCCB Operating Mechanism Based On Virtual Prototype

With the vigorous construction of new energy power systems and smart grids,the requirements for MCCB(Molded Case Circuit Breaker)are also constantly improving.Designing and developing MCCB according to the traditional physical prototype process,high material cost and longer development cycle will weaken the competitiveness of the product.This paper takes RMM2-630 direct-acting double-breakpoint MCCB as the research object,and studies the simplification of MCCB single-stage virtual prototype model,the electrodynamic characteristics of the contact system,the optimal design of the operating mechanism and the stress analysis of the member,the main works has been carried out as follows:1)Aiming at the problem of large workload and long simulation time when establishing a three-level or even four-level MCCB virtual prototype model in ADAMS.A model simplification method is proposed to calculate the mass of the contact mechanism to the middle level and to expand the stiffness coefficient of the contact spring.The effectiveness of this method is verified by comparing the simulation results.2)Based on Maxwell to study the dynamic characteristics of the direct drive type electrical double-break contact mechanism.Calculate the Lorentz force of the contact mechanism under different current and clearance between open contacts,and according to the formula and data,the Holm force at the touched contacts is obtained.In the ADAMS,the obtained electromotive force is applied to the dynamic contact bridge in the form of force by an interpolation function.The dynamic simulation of the type of circuit breaker breaking short-circuit current is realized,and the mechanical characteristics of the operating mechanism in this state are analyzed.3)Set the objective function,establish the mathematical model of the operating mechanism,and use the analytical method to determine the design variables used in the optimization design.A parametric model was built in ADAMS,and the results of ADAMS/View design study and ADAMS/Insight design of experiments were combined to determine the design variables that had the greatest impact on the objective function.The ADAMS embedded optimization function is used to optimize the design of the operating mechanism,which improves the spindle speed and reduces the free tripping action time.4)Co-simulation based on ANSYS/APDL and ADAMS/Durability,a rigid-flexible coupled virtual prototype model of the optimized operating mechanism is established.The dynamic stresses and distribution of the flexible body members such as jumpers and lower links during the tripping action are studied.The strength of the bars after optimization is in accordance with the design requirements.The research shows that the virtual prototyping technology can effectively simulate,optimize the design and stress analysis of the directacting double-breakpoint MCCB.