Control circuit design of AC frequency conversion systems for speed governing

According to the development of power electronic and control technology, the performance of AC frequency conversion system is as well as the DC system, and the former is substituting the later. The control system of AC frequency conversion for governing speed is evolving into digital system, gradually, with the introduction of microprocessor. This article elaborates the control circuit design of AC frequency conversion system for governing speed, which employs SCM(Single Chip Microcomputer) as its core, including hardware circuit design and software design. This design can make an immediate response to such abnormal phenomena on electrical machines as over voltage, over current, voltage deficiency and open circuit, and judge the breakdown type. After the breakdown is eliminated, the electrical machines automatically resume running. Wave shape is good in different frequency.