Abstract：With the increasing application of VVVF technology and constantly improving applied level, the accuracy requirement of VVVF control system is getting higher and higher. First, this paper presents a brief introduce to the VVVF system’s principle of work, theoretically analyzed the VVVF system's mechanical characteristics. Then the thesis deals with a rationale and realizable method of coming true the induction motor’s VVVF by PLC. Virtually, the PLC is a specialized computer of industrial control, it adopts the trapezoidal chart as the programming language and easily to learn. Furthermore, PLC also is an industrial control installment of taking the microprocessor as the core. It applies flexibly, operates easily, maintains simply, and the anti-jamming is strong, all these characteristic causes entire control system is enhanced greatly.
