Research On Control System Of Motor Operating Mechanism Of High Voltage Circuit Breaker

With the rapid development of modern power electronic technology and communication technology,requirements for the intelligent development of power grids are put forward.High-voltage circuit breakers play an important role in the protection and control of power grid operation in the power system.This paper takes the 126 k V three-phase high-voltage circuit breaker as the research object,selects the brushless DC motor operating mechanism to develop a better control scheme,and then meets the requirements for the intelligentization of high-voltage switchgear.In order to improve the operation level of the motor operating mechanism,this paper attempts to compare the characteristics of the moving contact control of the motor operating mechanism by using different control algorithms and different energy storage and discharge circuits.The main research work is as follows:（1）Theoretical analysis is carried out from two parts of brushless DC drive motor and operating mechanism transmission device respectively.According to the internal mathematical relationship and technical parameters of the brushless DC motor,build the Matlab simulation model of the brushless DC motor.Then,according to the principle and technical parameters of the transmission mechanism of the operating mechanism,the mathematical relationship of displacement,speed,load reaction force and opening and closing energy during the movement of the operating mechanism is established,and the corresponding moving contact displacement and time curve and load reaction curve.（2）Based on the establishment and application of traditional PI control algorithm,the application of fuzzy control algorithm and fuzzy neural network algorithm to the control system of motor operating mechanism is proposed by giving the opening characteristic curve with shorter time under ideal conditions.By adding the controllers of the three algorithms to the simulation model,the obtained speed follows the curve.It can be concluded that the speed error obtained by the fuzzy control algorithm and the fuzzy neural network algorithm is smaller and more stable,which reflects the fuzzy control algorithm and fuzzy neural network.The network algorithm has the characteristics of small overshoot,better stability and robustness,and higher control precision.（3）Design and build the hardware circuit of the motor operating mechanism.The hardware circuit of the entire control device takes the DSP chip as the core controller,mainly including the rectifier and inverter circuit,the isolation drive circuit,the signal acquisition circuit and other modules.According to the designed hardware circuit,write the corresponding software flow diagram to enable the realization of the circuit function,and complete the assembly and debugging of the control experiment platform.First,two opening and closing stability tests are carried out respectively.From the two opening and closing experiments,the time difference between the just-closing and just-closing of the circuit breaker is 0.3ms and 0.6ms respectively,which can prove that the circuit breaker control system has good stability.After that,under the same voltage and other environments,the traditional energy storage circuit and the switched capacitor bank circuit were used to carry out the opening and closing experiments.The use of the switched capacitor bank can shorten the response time of the motor closing by 5.3ms and the total closing time by 27.2ms.,the current amplitude has also been doubled;During the opening process,the switched capacitor circuit is used to increase the current extremely rapidly at the beginning of the motor,and the immediate response of the motor shortens the total opening time by 23.8ms.The results show that the switched capacitor bank circuit can increase the energy of the opening and closing experiment by multiplying the voltage,thereby increasing the opening and closing speed and shortening the opening and closing time,which has certain advantages.