With the continuous development of cranes, it is difficult for traditional control technology to meet the increasingly high speed regulation and control requirements of cranes. Today, with the rapid development of electronic technology, the combination of crane and electronic technology is becoming more and more close, and the AC variable frequency speed control device replaces the traditional motor rotor series resistance speed control method. Among many AC variable frequency speed control devices, D32 frequency converter has made it widely used in various applications due to its stability of performance, richness of option expansion functions, flexibility of programming environment, excellent torque characteristics and adaptability to use in different occasions. Inverter occupies a very important position in the high-end market.