A new low-cost electronic control circuit actuator is proposed for minimizing the bouncing times of an AC permanent magnet (PM) contactor after two contacts closing. The proposed new actuator overcomes the bouncing problem of an uncontrollable restrictions imposed by previously conventional AC electromagnetic (EM) contactor based on the minimization of kinetic energy prior to two contacts impact. By choosing the closing phase angle of coil voltage on purpose, the bouncing problems of the movable contact during the closing process are then overcome. The using life of contacts is then prolonged and their operating reliability is improved as well. In order to validate the feasibility and effectiveness of the proposed method here, several simulation and experimental procedures were performed on a prototype of AC PM contactor in the laboratory. Testing results actually showed that bouncing problem of contactor's contacts during the closing process was to be controlled by using the proposed technology.
This paper focuses on a novel control algorithm and its implementation method for providing voltage compensation to the coil of an AC electromagnetic contactor during voltage sags. Firstly, a new diagnosis algorithm is designed for correctly and timely detecting the voltage-sag event. When this new algorithm is embedded in the voltage compensation circuit and in series with the AC core of the contactor, the abnormal disengagement of the contactor contacts during voltage sag event could be eliminated through several experimental results. Another one designing point is that the dynamic position of armature can only be determined by a simple estimation method. In addition, the estimated position of armature and the applied voltage and coil current are taken as inputs by a single-chip based controller and provide the compensation voltage as output if voltage-sag event occurs. The above-mentioned new algorithm has been implemented in the laboratory.
This paper aims at studying the energy distribution in each subsystem during the closing process based on the equivalent electrical and mechanical models of contactor. On one hand, the more dynamic behaviors are related to contactor can be obtained; on the other hand, the end result is helpful to improve the performance of contactor. Based on easy modeling and high calculating efficiency, the magnetic circuit analysis method is adopted as the establishing approach of contactor model. The simulation model of contactor is implemented by using Matlab/Simulink software tool. The simulation results showed that the energy distribution in each subsystem critically depends on the initial phase angle of ac voltage source. If the contactor is supplied to some ac voltage source at a specified initial voltage phase angle, the moving velocity or kinetic energy of movable contact prior to collision is allowed to be effectively controlled. Therefore, the rebounding time of contacts after the first time close with fixed contact can then be reduced greatly.
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