Design And Control Of Permanent Magnetic Mechanism For 12KV Vacuum Circuit Breaker

Due to the complex environment under the mine,various faults such as electric leakage and short circuits often occur in the power grid.If they cannot be quickly removed,it is easy to cause serious consequences for the production and personal safety.Vacuum circuit breaker is one of the most important equipment of underground power distribution system,its performance will directly affect the safety and production efficiency of coal mine.A key component that determines the performance of vacuum circuit breaker is operation mechanism.The traditional operation mechanism has a complex structure and many components.In the process of action,it not only has low reliability,but also has large dispersion of breaking and closing time.In recent years,the emergence of permanent magnets has received widespread attention.It has a simple structure and only one moving part,and the operation is coordinated by permanent magnetic maintenance and electromagnetic operation,and is completed by electronic control.It is not only high in reliability,but also short in operation time and small in time dispersion.The research on the design method and control technology of permanent magnet mechanism can not only improve its own static and dynamic characteristics of the permanent magnet,but also help the development of synchronous closing technology.This thesis optimizes the design of permanent magnet mechanism of 12KV vacuum circuit breaker that used in underground 11.4KV central substation.The permanent magnetic mechanism is maintained by permanent magnets and the excitation control systems realize the action of breaking and closing,so the design of this thesis is mainly from two aspects:the first is to design the structure of the permanent magnet mechanism,and the second is to design the external excitation control part.Firstly,the design object is the bistable permanent magnet mechanism which is easy to control.Then,the size and material of each part of the object are selected and calculated,and the two-dimensional model of permanent magnetic mechanism is created by the finite element software Ansys Maxwell for the simulation calculation of static and dynamic characteristics.Secondly,a control concept based on the coil current PID hysteresis control of the permanent magnet mechanism is adopted for the decentralization of the breaking and closing time in the synchronous closing control.The Matlab software is used to simulate the control model,so that the output of the breaking and closing current curve of the permanent magnetic mechanism can quickly track the given current curve,so as to ensure that the dispersion of the breaking and closing time becomes smaller.On this basis,the hardware and software of the permanent magnet mechanism control system are analyzed and designed.Finally,the no-load experiment is carried out on the model,which verifies that the design meets the requirements.