Research On Displacement Tracking Control Of Vacuum Switch Contact

In the process of power equipment input and removal,the electromagnetic transient process will be generated in the power system.Large inrush currents and transient overvoltages will be found due to inappropriate switching time points,which in turn will have a huge impact on power equipment,and the insulation strength and service life of equipment will be affected.The controlled switch technology is adopted to switch on and off is the most cost-effective method to solve this problem.Vacuum switches are widely used in 10 kV power systems because of their high reliability,good insulation properties,and pollution-free characteristics.Therefore,the vacuum switch is taken as the research object,and the combination of modern control technology and power electronic technology is used to control the displacement of the vacuum switch contact.First of all,the current shortcomings of the traditional operating mechanism of switch are introduced in this article.The principles,advantages and control methods of the permanent magnet actuator(PMA)are analyzed.The dynamic process of PMA is studied,the numerical simulation analysis is performed,and the factors that affect the dynamic process of the PMA are analyzed,including capacitor voltage,idle time,temperature and so on.Secondly,it is divided into excitation phase control and motion phase control according to the operating characteristics of PMA.Secondly,it is divided into excitation phase control and motion phase control according to the operating characteristics of the PMA.PID current tracking is used as the excitation stage controller.The non-linear relationship space between the electromagnetic force,coil current and contact displacement is introduced to simplify the PMA mathematical model,and then the double closed-loop control is adopted to improve the control method in the motion stage.After that,a numerical simulation analysis was carried out,and compared with the traditional black box control method,it was verified that the double closed-loop control is more effective.Thirdly,the overall hardware control system of PMA was designed,DSP28335 was used as the control system hardware experiment platform,and the hardware and software design of the system was carried out.The two parts of control and driving are taken as the hardware main body,the sensor is selected and the hardware circuit is designed.The timer interrupt strategy is adopted to realize both timing and algorithm procedures in parallel,thereby ensuring the accuracy of the control time.At the same time,the acquisition,filtering,controller and PWM wave output programs are added to realize the software design of double closed loop control.Finally,the vacuum switch experimental platform is designed,the actual electromagnetic force characteristics of PMA are measured using the designed experimental platform,and the nonlinear space of electromagnetic force is extended by BP neural network algorithm.The control algorithm proposed in this paper has been verified by experiments.When the capacitor voltage,capacitance and load are changed,the controller can achieve the dispersion of the closing time of the circuit breaker within ± 0.5ms.