Research On Asynchronous Servo Driver For The Injection Molding Machine

An Injection molding machine consists of two main parts, an injection unit anda clamping unit.The injection molding process consist of shut of mold,injection,plasticmelt,opening mold,and so on.Traditional injection molding machines use generalasynchronous motor to drag oil pump,the motor runs on rated speed.In other words,the followof oil pump is always maximal,redundant oil returns tank through spill valve.As the powerconsumtion is proportional to the follow and pressure of oil pump,a large amount of power (aslarge as30%~70%) is wasted.By the use of sensorless vector control technique,the speed ofmotor can be changed along with the follow signal of injection molding machine in time.Inthis way,power consumption can be reduced dramaticly.To insure production efficiency,t hespeed of motor must be adjusted quickly enough.At the same time, it’s only the pressure ofthe hydraulic system being kept large enough that the quality of products can beguaranteed,so the motor must output enough torque.In the first,this paper states the background,importance and current situation ofasynchronous servo driver for injection molding machine,then discusses it’s performancerequerements according to injection technology.In the next,this paper starts from the dynamicmathematical model of asynchronous machine,uses space vector theory to explain theprinciple of field oriented control of induction machine,and introduces the structure ofasynchronous servo driver for injection molding machine.Then this paper narrates thedesigning process of high-performance asynchronous motor driving system for injectionmolding machine,which consists of some techniques,such as speed and flux identificationbased on MRAS,parameter auto designing for PI regulators,and so on.In this paper,various control techniques are also explained by simulation based on Matlab/Simulink.The realizationof hardware and software of high-performance asynchronous motor driving system forinjection molding machine are illustrated simply.After stating the dynamic mathematical model of asynchronous machine、field-oriented-control of induction machine and key technologies in detail,this paperintroduces the realization of hardware and software of the system,and includes the results ofexperiments.