The selection of low-voltage general-purpose ac drives includes two aspects: type selection and capacity selection. The principle of selection is: first of all, its functional characteristics can ensure reliable realization of process requirements, and secondly, to obtain a better performance-price ratio.

A frequency converter is a power control device that converts a power frequency power supply into another frequency by using the on-off function of a power semiconductor device. First, the power frequency AC power is converted into DC power through the rectifier, and then the DC power is converted into AC power with controllable frequency and voltage to supply the motor.