基于SPWM的正弦波设计与实现

Design and Realization Based on the SPWM Sine Wave

PWM是D/A转换的一种方法,当PWM中的调制信号为正弦波时,得到的是SPWM波形。采样控制理论中有一个重要结论是冲量相等而形状不同的窄脉冲加在具有惯性的环节上时,其效果基本相同。SPWM法就是以该结论为理论基础。通过面积等效法确定SPWM的脉冲宽度,运用数学软件MAPLE进行运算,按照严格的时序控制输出波形。采用VHDL硬件描述语言进行设计实现并使用Max+PlusⅡ进行仿真验证,得到一组随着脉宽变化的数字信号。根据D/A转换器原理,把SPWM波形转换成正弦波输出。

PWM is one method of D/A transformation. When PWM modulation signal is sine wave, SPWM waveform is obtained. In sampling control theory, there is an important theory that its effect is basic same when the pulse with the impulse are equal but the shape is different. The principle of SPWM takes the conclusion as the ratlonale. The pluse width of SPWM is determined by method of equiralent area it carries on the operation using mathematics software MAPLE,according to strict sequential control output wave shape. Using the VHDL hardware description language to carry on the design to realize and use Max＋Plus Ⅱ to carry on the simulation confirmation,obtalning a group dlaital signal along with pulse width change. According to the D/A switch principle ,to make the SPWM profile tranforms into the sine wave and then output.