The Design Of The Commutating Logic Circuit Without Circumfluence And The Digital Pulse Flip-flop

Based on investigating the theory of the model of the synchronous motor and vector control, this thesis designed the measuring device for detecting current crossing zero, the commutating logic circuit without circumfluence, the digital pulse flip-flop circuit. The measuring device for current crossing zero presented the characteristic of quick response, good sensitiveness. Due to the introduction of the CPLD, the commutating logic circuit without circumfluence and the digital pulse flip-flop circuit represented to be more rapid, more flexible and good performance.The commutating device measuring for detecting current crossing zero in this thesis is to detect the voltage drop. When the thyristor switches on, the voltage drop is zero. And when the thyristor switches off, the voltage drop is non-zero. So if none of the six arms is zero, it indicates the state of non-zero. However, if the voltage of one arm is zero, it indicates the state of zero.Due to the real-time requirement of the commutating logic circuit without circumfluence, the two levels delay is very short, the logic is simple, so it is not fit to use software. The thesis adopted CPLD to accomplish it.