Research and Design of Discrete Frequency Conversion Soft Start

Aiming at the problem of high impulse current and low initial torque of three-phase asynchronous motor under the traditional starting modes, the soft starting technology of discrete frequency conversion is adopted to realize the full or heavy load starting of the motor. For the different trigger modes of the thyristor, a five-pulse sequence trigger mode is adopted, that is, five-pulse sequences are used instead of the wide pulse, which solves the problem that the conventional trigger modes cannot trigger effectively. Finally, the system simulation model is built and the hardware system based on DSP is constructed, which verifies the correctness of the theory.