Hardware such as domestic DC servo motor and drive technology matures, in soft form exists in the control chip restricting our servo control technology in high performance permanent magnet DC motor technology and product development bottleneck. With the rapid development of modern industry, marking the appropriate equipment such as a country's industrial strength precision machine tools, industrial robots, such as on the "driver"-these are the permanent magnet DC motor is an increasingly high demand. Permanent magnet DC motor based on sinusoidal EMF for outstanding performance have become increasingly electrical servo system of motor "mainstream". Modern power electronics, microelectronics and computer technology, supporting the rapid development of technology, as the executing agency for permanent magnet DC motor AC servo drive system development greatly. However permanent magnet AC servo system of DC motor control technology is to determine the performance of one of the key technologies, is a major part of foreign exchange servo technique blocked.