说明：  pid控制单片机编程 DA模块两路（OUT1、OUT2）输出三角波经AD10次采样并与 之比较经数字滤波、双闭环PID调节后PWM生成以及经逆变后 电压控制
(pid control of single-chip programming two-way DA module (OUT1, OUT2) output triangle wave by AD10 and compared with samples by the digital filter, double-loop PID regulator as well as after the PWM inverter generates voltage control after)