The Study Of Motor Soft Starter Based On CAN Field Bus

The motor soft starter is a new technique of the fastest development, which can not only adjust the motor current of start and stop, but also rectify starting torque and perform soft-stop. It has outstanding performance in the face of protection of driving gear and maintenance the quality of electric network. However, at present, the asynchronous motor soft starters of local production have mostly not communication interface. Even some have communication interface, which is either RS232 or RS485.These serial buses are not suitable for industrial field control because of their characteristics. Those hold back the further development of motor network and the realization of management integrated with control and synthetic automation. Field-bus technology is hotspot talked about by all over world. And fully digital control system based on field bus is the mainstream of automatic-control system in the 21st century. As a kind of rising field bus technology, Controller Area Network (CAN) delivers data by use shorter frame and filter mechanism. CAN has the specialty of high dependability, high real time and flexile performance. The distributed network based on CAN bus can be conveniently construct and meet demand of practical engineering in lower cost. On the basis of study the shortage soft starters of local production and good quality of field bus, a design scheme of asynchronous motor soft starter based on CAN is proposed. In this paper, firstly, starting method of asynchronous motor and the CAN protocol are studied. Then software and hardware of digital soft starter embedded CAN interface is design. At the same time, design is feasible and performance is stable by practice. Key words: Field bus, Asynchronous motor, Soft starter, CAN bus...