with the rapid development of power electronic technology and new semiconductor devices, ac speed regulation technology has been continuously improved and improved. the gradually improved frequency converter has been widely used in ac motor with its good output waveform and excellent performance price ratio. for example, ac variable frequency speed regulation motors have been successively used in large motors, medium and small roller table motors, traction motors for railway and urban rail transit, elevator motors, lifting motors for container lifting equipment, motors for water pumps and fans, compressors, motors for household appliances, etc. in steel mills, and good results have been achieved.
working principle of variable frequency motor: the main circuit is the power conversion part that provides voltage and frequency regulation power supply for asynchronous motor. the main circuit of variable frequency motor can be generally divided into two categories: voltage type is the variable frequency motor that converts the dc of voltage source into ac, and the filter of dc circuit is capacitor. current mode is a variable frequency motor that converts the dc of current source into ac, and its dc circuit filter is inductance. it consists of three parts, which converts power frequency power supply into dc power ldquo; rectifier;, absorb voltage pulsations generated in converters and inverters ldquo; smoothing circuit;, and converting dc power into ac power ldquo; inverter rdquo;.