zero time reference

A real-time current detection based on FBD ( Fryze-Buchholz-Dpenbrock) method is pre-sented to detect the harmonic, negative-sequent and zero-sequent currents in three-phase four-wire system, and the essential of the method is the projection transformation of reference voltage.

为了快速、有效地检测出三相四线制电力系统中的谐波、负序和零序电流，提出了一种基于FBD法的电流实时检测方法。

MCU get timing reference by zero-crossing detection. It compare the current speed feedback with the object feedback, and control the conduction phase and time using PWM mode to realize the stable speed-regulating of AC PG-motor.

单片机通过过零检测获取计时基准，比较当前转速反馈与目标反馈，采用脉宽调制PWM方式来控制三端双向可控硅开关器件的导通相位角及导通时间，实现交流PG电机的平稳调速。