Research of selection phase angle and dynamic control for closing process of intelligent AC contactors

摘要

The closing process of intelligent AC contactor can be affected by selection phase angle and the dynamic control strategy. A control strategy is proposed to compensate the influence of closing process at different phase angles. The mathematical model of the closing process is established by analyzing the dynamic characteristics of the contactor. Simulation and experimental comparisons show that the proposed model can predict the dynamic response of the closing process effectively. The relationship between the closing phase angle and the end speed is analyzed by using the experimental measurements. The selection phase angle and dynamic control is implemented by combining voltage zero crossing and PWM section control technology. The input voltage and the zero-crossing signal are taken as the control input while the PWM duty cycles and the strong excitation time are taken as the control output. The control strategy is implemented by using the lookup table. Experimental results show that by using the proposed strategy, the contactors can be closed with the same phase angle. Therefore the consistency of the dynamic closing process of the intelligent contactors can be guaranteed. Also, the movable armature end speed of the closing is reduced 31.5% and the closing time is decreased 15.6%. The mechanical life of the contactor has been increased about 4 times in the durability test.