Design And Implementation Of Intelligent Control System For AC Contactor

The AC contactors are low voltage electrical appliances which are widely used in motor control and distribution systems.With the advancement of science and technology and the increase in demand for electricity,the market has put forward higher requirements for the performance of the AC contactor.The traditional AC contactor has obvious bounce during the closing process,high energy consumption during the closed process,arcing during the breaking process,and no abnormal protection and remote monitoring functions.Therefore,in view of the problems existing in traditional AC contactors,under the premise of reasonable control system cost,this thesis optimizes and designs an AC contactor intelligent control system and verifies its function.Firstly,this thesis studies the development status and development trend of the contactor industry.On the basis of mastering the working principle of the AC contactor,the mathematical model analysis of the contactor working process is carried out with the contact state as the entry point,and the factors affecting the working performance of contactors are discussed.Based on the above analysis,the overall design scheme of the AC contactor intelligent control system is proposed.Secondly,combined with the overall scheme design,the hardware system and software system of the intelligent control system are optimized respectively.For the hardware system,the thyristor drive circuit,the coil drive circuit and the three-phase electric signal acquisition circuit are optimized respectively,which improves the anti-interference ability of the hardware circuit.For the software system,the algorithm flow of each sub-task is optimized,the code volume is reduced,and the stability and reliability of the software system are improved.Through the interaction between the software system and the hardware system,the DC high voltage applied to both ends of the coil is controlled by PWM(Pulse Width Modulation)to reduce the contact bounce phenomenon in the closing process of the contactor;Energy-saving and noise-reduction of the AC contactor holding process is realized by controlling the DC small voltage applied across the coil with a high level;the contact erosion problem of the AC contactor breaking process is solved by the thyristor driving circuit;the working process of the AC contactor is completed by the STM32F103 controller In the opening and closing control,data acquisition,local display,abnormal protection and network communication functions.Finally,for the test prototype CDC6-400 AC contactor,the functions of the intelligent control system were tested and analyzed,and the function realization of the intelligent control system was verified,which has certain practical application value.