A Rotor Position Detecting Method Based on Signal Injection for LCI Fed Electrically Excited Synchronous Motors

A new rotor position sensorless detecting method based on high power electrically excited synchronous motors is proposed. The central idea is the back electromotive forces contain the information of rotor position, when a high frequency signal is injected in the rotor by excitation part. So the rotor position can be obtained by detection and calculation of motor back electromotive forces. By experimental verification, high frequency signal injection method has a very good effect and can eliminate the negative impact of opposite rotating direction and pulsation problem at the early in the starting process.