Research And Design Of Large Capacity Separation Frequency Conversion Intelligent Soft Starter

Asynchronous motor is one of the important part of intelligent thyristor of intelligent control,because of the traditional electric chance to generate excessive current,it affect safe operation of power grid.The hierarchical variable frequency soft starter is a kind of electronic motor control equipment.Based on thyristor controlled asynchronous motor adopts synchronous open circuit technology,weakened the motor starting voltage,avoid the excessive current damage.It make intelligent thyristor control rapidly applied to practice.In this paper.the characteristics of induction motor and the frequency conversion strategy are analzed.Using MATLAB to establish a model for different starting modes of the motor,the starting current and the starting torque are seen by the wavefonn diagram.Soft-start system is composed of hardware and software components and are introduced separately in these two parts.The soft starter to dsPIC30F6014A as the control core,the PIC minimum system,the system power supply voltage supply circuit,drive control circuit,zero-crossing detection circuit and communication circuit were designed in detail,according to the principle of harmonic interference classification to solve the various circuit modules interference problem.Software design based on PIC MPLAB software platform,it use of C language programming mode to improve the speed of operation.Completed A/D sampling design,current-limiting starting design,initialization and synchronization signal interruption,etc.The linear FIR filter algorithm part design,gives the specific procedures for zero value algorithm design.The simulation results show that the soft starter can obviously improve the asynchronous motor starting performance,reduce to the impact of the power grid,smooth and reliable starting.Finally,the paper summarizes the full text work deficiency and prospected.