Discrete variable frequency stepless voltage regulation soft starting device based on speedless sensor

The utility model discloses a discrete variable frequency stepless voltage regulation soft starting device based on a speedless sensor, which belongs to the technical field of starting of motors and mainly solves the problems that a starting torque must be seriously reduced when a starting voltage of the conventional soft starting device is reduced and the soft starting device is difficult to start with a heavy load. The device is mainly characterized by comprising a main loop and a main loop control circuit, wherein the main loop is formed by sequentially connecting five groups of conversed-paralleled controlled silicon, the main loop control circuit comprises a digital signal processor (DSP) controller, a current signal zero-crossing detection circuit, a voltage sampling circuit, a current sampling circuit, a synchronous signal acquisition circuit and drive circuits, the voltage sampling circuit and the synchronous signal acquisition circuit are connected between the main loop and a DSP, the current sampling circuit and the current signal zero-crossing detection circuit are connected between the main loop and the DSP, and the drive circuits are connected between control ends of the controlled silicon of the main loop and the DSP. The discrete variable frequency stepless voltage regulation soft starting device has the characteristics of low starting current, high starting torque and smooth switching according to frequency ranges, and is mainly suitable for a starting occasion of a three-phase asynchronous motor with the heady load.