Affiliations: [a] The Key Laboratory of Low-Voltage Apparatus
Intellectual Technology of Zhejiang, Wenzhou University, Wenzhou, Zhejiang, China | [b] Wenzhou Juchuang Electrical Technology Co., Ltd., Wenzhou, Zhejiang, China
Correspondence:
[*]
Corresponding author: Guichu Wu, The Key Laboratory of
Low-Voltage Apparatus Intellectual Technology of Zhejiang, Wenzhou University,
Wenzhou 325027, Zhejiang, China. E-mail: wgc@wzu.edu.cn
Abstract: 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.
Keywords: PWM, selection phase angle control, intelligent contactor, voltage zero crossing
