The Study And Exploitation Of Fully Digital Explosion-Proof AC Motor Soft Starter

Among the modern industrial control fields, the research of AC motor start control is an important task. AC motor soft starter, with its soft starting, small impulse current, no contacts, and energy saving, has gained widely use in electric transmission. In this paper, contraposing to the special demand of explosion-proof, it presents a kind of comparatively ideal design scheme of fully digital explosion-proof AC motor soft starter, which has been validated through the experiments.Firstly, the paper introduces the development of AC motor soft starter. Then, on the base of analysis and compare, it brings forward a new way to accomplish the motor soft starting. In addition, it gives an expatiation of the soft starter, including the operation principle, the main circuit design and the design of its explosion-proof structure.The application of multiple digital phase-locked technology and the high frequency complementary symmetrical pulse technology is the key content discussed in the paper. Centering on this, the paper analyses the phase-locked loop, the characteristics and application of HEF-4046BT, the circuit constitute of 8254, and the elimination of interference in the control system.Furthermore, the paper introduces some other characteristics of the soft starter, the hardware experimental circuits of its MCU control system and the whole design philosophy of its software, together with the main program flow chart.