Hardware Design And Implementation Of Intelligent Contactor Control System Based On ARM

AC contactor is a switch control electrical appliance which is widely applied in low voltage power distribution system.Due to frequent operation on the AC contactor in power distribution system,the reliability of contactor control is related to the safety operation for power system.The main factor which restricts the service life of contactor is that the electric arc caused by contacts bounce which brings about erosion.It is also the bottleneck for AC contactor development.Researchers at home and abroad have done lots of work based on theories analysis with few improvements and applications on products.Concerning the deficiencies on existing AC contactors products,an intelligent control system has been proposed and devised while experiments have been done on prototype system.To begin with,the thesis introduces the fundamental structure and principle of traditional electromagnetic AC contactor and analyzes attractive force,spring force and contact kinetic energy during switching process.According to the theory and data contrast,it is obvious that traditional AC contactor control methods exit deficiencies.In view of this,it is proposed to apply more intellectual and improved control methods which substitute DC excitation power for AC excitation power.Electromagnetic coil is exerted by high voltage power during switch-on period while low voltage power during holding period.Pulse Width Modulation control is put to use in the light of experimental situation which is effective to make the combination of attractive force and spring force more sensible as well as optimize switch-on dynamic process.Thyristor is paralleled to the ends of contacts for shunting the current which could reduce the erosion caused by electric arc during switch-off period.As a result,it is able to prolong the service life of contactor.Besides,combined with application occasions and control requirements,this thesis puts forward and designs an AC contactor intelligent system based on S3C6410 chip.With modularization thought,the peripheral hardware circuits conformed to the functional requirements are designed consisting of coil drive circuit,thyristor drive circuit,three-phase voltage acquisition circuit and three-phase current acquisition circuit.On the basis of theory analysis and software and hardware design,the circuits boards for certain functions are printed.Finally,in allusion to optimal issues,experiments have been carried out to verify the performances based on Delixi CDC6-400 AC contactor prototype system.The experimental results show that the intelligent AC contactor control system put forward in this thesis could effectively improve the dynamic performance of contactor in three aspects including switch-on,switch-off period and condition monitoring.The AC contactor control system designed in this thesis has certain practical application value.