Soft starter for line-start permanent magnet synchronous motor (LS-PMSM)

Abstract

The invention discloses a soft starter for an LS-PMSM. The soft starter is characterized in that the output end of a starting and halting control circuit and the input end of a thyristor drive circuit are respectively connected with the I / O port of a microprocessor circuit; the output end of the thyristor drive circuit is connected with the drive input end of a thyristor module; the output end of a three-phase power supply circuit is connected with the power supply end of the microprocessor circuit through a power-switching circuit; the output end of a soft starting and direct starting control circuit is connected with the control input end of a switching circuit; the output end of the switching circuit is connected with the drive input end of a thyristor module; and the output end of the three-phase power supply circuit is connected with a power supply system of a grid. According to the soft starter for the LS-PMSM, the problem of great impact on the grid and mechanical equipment caused by large starting current during a direct starting of the LS-PMSM is solved, the starting current is reduced, and applied range of PMSM is increased.

Description

technical field [0001] The invention relates to the technical field of motor starting, in particular to a soft starting circuit device capable of controlling the starting current of an asynchronous starting permanent magnet synchronous motor and automatically reducing the starting current. Background technique [0002] Three-phase induction motors are widely used in industrial and agricultural production and daily life. The main characteristics of three-phase induction motors are: ①Simple structure, convenient manufacture, low price, and reliable operation; ②There is no strict fixed relationship between the speed and power frequency, and the speed changes with the load, but the range of change is not large; ③Absorbed from the power grid Lagging reactive power, power factor is always lagging; ④ Efficiency and power factor vary greatly with the load, at light load, the efficiency and power factor are low, and the economical operation range is not wide. [0003] During the per...

AI Technical Summary

Problems solved by technology

[0006] In order to solve the problem in the prior art that when the asynchronous start permanent magnet synchronous motor is directly started, the starting current is large, causing a large impact on the power grid and mechanical equipment. During the step-down starting process of the motor, if it is detected that the load current has an obvious downward trend, the working voltage of the motor will be increased rapidly to increase the output torque of the motor.

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