注塑机改造中 PWM波形的电压转换方法研究

摘要

讨论在传统液压型注塑机改造为混合型注塑机过程中将PWM信号转换为0～10 V线性直流电压供伺服调速使用的方法，提出RC转换电路和单片机采样电路两种转换方案，通过分析实验数据比较采用这两种方法时PWM波形的脉冲宽度变化时的跟踪特性、纹波特性，可知单片机采样系统具有更快的跟随特性、更小的纹波系数。最终在实际应用中取得了良好效果。%A method applied to the equipment reform from traditional type hydraulic injection molding machine to mixed injection machine was discussed,which could be used to convert pulse width modulation (PWM)signal to 0~10 V linear DC voltage. The DC voltage could be used to control and change the speed of servo motor. Two transformation schemes:RC conversion circuit and singlechip microcomputer (MCU)sampling circuit were put forward. By analyzing the experimental data,the characteristics of tracking and rippling were compared during changing of the pulse width of PWM waves in application of these two methods. It is concluded that the MCU sampling circuit has better characteristics than RC conversion circuit for its faster tracking speed and smaller ripple coefficient. The MCU sampling circuit has been applied in practice and good result is achieved.