Analysis Of A Permanent Magnet Intelligent Circuit Breaker And Controller Design

With the rapid development of the national economy and the "energy conservation" policy, the permanent magnet intelligent circuit breakers are important parts in power system to protect the electrical distribution network and industrial equipment from being short-circuit, overload, the leakage and other hazards of key electrical equipment failure. The research of permanent magnet intelligent circuit breakers is presented in this paper. This paper demonstrates the composition of permanent magnet intelligent circuit breaker and main characteristics, and focus on the design of the intelligent controller to realize intelligent circuit-breaker protection. According to the characteristics of circuit breakers and permanent magnet manipulation, high-performance DSP chip TMS320F2812 is applied as the central processor with modular designing concept to design the intelligent controller hardware and software in detail. This paper focus on the hardware circuit design for data acquisition, power supply, communications, trip execution, temperature detection, keyboard input, and these liquid crystal display modules, and each module is given a key part of the circuit diagram and brief design method; considering the characteristics of hardware circuit and permanent magnet intelligent circuit breaker controller , software part is divided into sampling, communications, FFT calculation, three sections-current protection, keyboard input and LCD display module , for each module design idea is introduced and software flow chart presented . In view of the harsh electromagnetic environment for circuit breakers, the paper introduces some hardware and software measures to improve anti-interference ability of the controller.Currently, most intelligent controller is designed based on SCM considering its low price and simplicity,in order to meet Grid's requirements for rapid response and high precision, DSP is applied to design the intelligent controller in this paper. Instantaneous short-current algorithm based on three-point sliding window fits DSP and can unify reliability and fast response.The intelligent controller designed in this paper is applied to an intelligent circuit breaker for the test of three sections-current protection and other experiments. The results show that the design of the permanent magnet intelligent circuit breaker controller basically achieves the desired design goals.